8 The Rate of Contemporary Drug Discovery BARRY M . B L O O M M e d i c a l Research Laboratories, Pfizer Pharmaceuticals, Groton, C o n n . 06340
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While
the rate at which
received
regulatory
new single
approval
and
United
States during
until the early 1960's, it has declined by drug category,
ately
preceding
Law
Amendments,
that appear while certain
One
important vascular
vexing
and
approval, medical
vitally problems
and pulmonary
newly introduced
cancer
drug
the con-
since.
periods
immedi-
1962
Drug
for the
decline
U.S.
observation
central
drugs
in
sharply
to the evolving
particularly
products
increased
of the
some reasons
types of drugs, notably
antibiotics,
regulatory
passage
to be attributable
tory climate. agents,
identifies
1941-1970
comparing
and following
drug
introduced
tinually
An analysis
the period
entity
were
regulais that
nervous
continue
system to
gain
needed types of agents for
other
of our time,
such
diseases, are notably
as
cardio-
absent
among
products.
T n t r y i n g to u n d e r s t a n d the m e c h a n i s m of a process, chemists often A
find
i t e n l i g h t e n i n g to a n a l y z e the rates i n v o l v e d . I n l i k e f a s h i o n , n e w
insights i n t o the nature of c o n t e m p o r a r y d r u g d i s c o v e r y m i g h t b e o b t a i n e d if w e c o u l d l e a r n about the rate at w h i c h that process has o c c u r r e d i n recent years.
T h e r e has b e e n m u c h discussion r e c e n t l y about a d e c l i n e
i n the rate at w h i c h n e w d r u g s are b e i n g d i s c o v e r e d a n d m a d e a v a i l a b l e for m e d i c a l use. T h i s p a p e r assesses the rate of n e w d r u g p r o d u c t i n t r o d u c t i o n over the last 30 years, a p e r i o d w h i c h corresponds essentially to the entire m o d e r n era of d r u g research. T h e a p p r o a c h is to a n a l y z e a list of the basic n e w agents i n t r o d u c e d to m e d i c a l p r a c t i c e i n the U . S . since 1941, u s i n g t h e D e H a e n " N e w P r o d u c t S u r v e y " a n d " N o n - P r o p r i e t a r y N a m e I n d e x " as p r i m a r y source materials ( J ) .
T h e D e H a e n lists, w h i c h c o n t a i n m a n y k i n d s of n e w d r u g
p r o d u c t s , h a v e b e e n c u l l e d a c c o r d i n g to a set of e x c l u s i o n rules w e h a v e d e v i s e d to m a k e t h e m a m o r e m e a n i n g f u l i n d e x o f t h e rate of bona drug discovery. 176
Bloom and Ullyot; Drug Discovery Advances in Chemistry; American Chemical Society: Washington, DC, 1971.
fide
8.
BLOOM
Contemporary
Drug
177
Discovery
A c c o r d i n g to these rules, a d r u g p r o d u c t w a s i n c l u d e d i n o u r e d i t e d list o n l y i f i t was, at the t i m e of m a r k e t i n t r o d u c t i o n , a n e w , single c h e m i c a l e n t i t y i n t e n d e d f o r h u m a n t h e r a p e u t i c use, that d i d n o t f a l l into a n y of the f o l l o w i n g , e x c l u d e d categories: b i o l o g i c a l s s u c h as vaccines; d i a g nostic aids; h o s p i t a l solutions; n o n - a b s o r b e d h i g h m o l e c u l a r w e i g h t c o m p o u n d s ; i m p u r e extracts of n a t u r a l o r i g i n ; n e w uses a n d / o r f o r m u l a t i o n s of p r e v i o u s l y m a r k e t e d d r u g s ; n e w single components i n c l u d e d i n p r e v i o u s l y m a r k e t e d mixtures; a n d n e w salts of p r e v i o u s l y m a r k e t e d d r u g s . A l t h o u g h n e w salts have b e e n e x c l u d e d , o u r e d i t e d list does i n c l u d e n e w esters a n d other c o v a l e n t l y b o n d e d derivatives of p r e v i o u s l y m a r k e t e d drugs. Downloaded by CORNELL UNIV on September 27, 2016 | http://pubs.acs.org Publication Date: June 1, 1971 | doi: 10.1021/ba-1971-0108.ch008
T h e i n h e r e n t l i m i t a t i o n s of this a p p r o a c h are r e a d i l y apparent. B e cause i t is the o n l y f o r m i n w h i c h c o m p r e h e n s i v e data are a v a i l a b l e to us, w e h a v e h a d to use dates of U . S . n e w p r o d u c t i n t r o d u c t i o n s as a n i n d e x of the rate at w h i c h n e w d r u g s are b e i n g d i s c o v e r e d t h r o u g h o u t the w o r l d . T h e justification f o r a s s u m i n g that there is a c o r r e l a t i o n b e t w e e n the t i m e w h e n a d r u g is first d i s c o v e r e d a n d the date w h e n i t is i n t r o d u c e d i n the U . S . m a r k e t derives f r o m the c o n s i d e r a t i o n that, i n a l l l i k e l i h o o d , the sponsors of a n y significant n e w d r u g t o d a y w i l l b e s t r o n g l y m o t i v a t e d to m a k e i t a v a i l a b l e c o m m e r c i a l l y i n the U n i t e d States as soon as possible. R e c o g n i z i n g that the t i m e p e r i o d f r o m d i s c o v e r y to U . S . m a r k e t introd u c t i o n is l i k e l y to differ s i g n i f i c a n t l y f r o m case to case, w e have sought to m i n i m i z e this p o t e n t i a l source of error b y r e s t r i c t i n g the analyses to comparisons i n v o l v i n g p e r i o d s of n o less t h a n five years. A n y effort to d e t e r m i n e w h i c h d r u g p r o d u c t s deserve to b e o n a list restricted to n e w , single c h e m i c a l entities is b o u n d to l e a d to a f e w quest i o n a b l e j u d g m e n t s , a n d the s i m p l e exclusion rules w e u s e d are n o exception. H o w e v e r , the n u m b e r of d e b a t a b l e cases i n this study is too s m a l l to cause a n y serious c o n c e r n . W e have n o t a t t e m p t e d to d i s t i n g u i s h the d i f f e r i n g degrees of i n n o v a t i o n that i n d i v i d u a l discoveries represent.
W e treat a n u n i m p o s i n g
m o l e c u l a r m o d i f i c a t i o n of a w e l l - e s t a b l i s h e d t h e r a p e u t i c p r i n c i p l e as i f i t w e r e e n t i r e l y e q u i v a l e n t to the d i s c o v e r y of p e n i c i l l i n G or cortisone. A t t e m p t s to assess c o m p a r a t i v e degrees of i n n o v a t i o n a n d m e d i c a l significance objectively are so d i f f i c u l t that despite the p o t e n t i a l v a l u e of s u c h j u d g m e n t s i n a s t u d y l i k e this one, efforts to d o so m u s t r e m a i n outside the scope of this p a p e r .
Analyses of Data W e have a n a l y z e d o u r e d i t e d list to see i f i t supports t h e w i d e l y h e l d c o n c l u s i o n that the rate of n e w p r o d u c t i n t r o d u c t i o n has s l o w e d signific a n t l y of late.
T a b l e I gives clear e v i d e n c e that this is true.
W e have
c a r r i e d o u r analysis t h r o u g h A u g u s t 1970 a n d b r o k e n t h e 30-year p e r i o d u n d e r s t u d y into
five-year
segments.
Bloom and Ullyot; Drug Discovery Advances in Chemistry; American Chemical Society: Washington, DC, 1971.
178
DRUG
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Table I.
DISCOVERY
Rate of N e w Product Introductions By Category Five-Year Period
A v e r a g e N u m b e r of Basic New Agents Introduced Per Year
1941-45 1946-50 1951-55 1956-60 1961-65 1966-70 ( t h r o u g h A u g u s t )
10 18 31 39 20 12
T h e rate that p r e v a i l e d d u r i n g t h e w a r years (1941-45)
increased
steadily to a m a x i m u m d u r i n g t h e last h a l f of t h e 1950's, w h e n n e w entities w e r e b e i n g i n t r o d u c e d at a n average rate o f almost 40 p e r year. T h e r e w a s a sharp d e c l i n e i n 1962, c o i n c i d i n g w i t h t h e passage o f t h e K e f a u v e r - H a r r i s A m e n d m e n t s to t h e F o o d a n d D r u g s A c t late that year. T h e n e t effect w a s a decrease b y h a l f of the rate o f n e w p r o d u c t i n t r o ductions
d u r i n g the p e r i o d 1961-65 i n c o m p a r i s o n w i t h t h e p r e v i o u s
p e r i o d . T h e rate d e c l i n e d f u r t h e r , b y almost h a l f a g a i n , i n t h e present five-year
p e r i o d , r e a c h i n g a l o w i n 1969, w h e n o n l y seven
a p p e a r o n t h e list. U.S.
compounds
( O n t h e other h a n d , 11 b a s i c n e w agents g a i n e d
r e g u l a t o r y a p p r o v a l d u r i n g the first eight m o n t h s of 1 9 7 0 ) . N e x t , w e c o m p a r e d the p r o d u c t i v i t y o f each five-year p e r i o d t o deter-
m i n e w h e t h e r a n y factors that m i g h t b e responsible f o r i n d u c i n g i m p o r tant changes i n t h e rate o f e m e r g e n c e of n e w p r o d u c t s w e r e d i s c e r n i b l e . A l t h o u g h t h e conclusions w i l l h a r d l y p r o v e s u r p r i s i n g , they d o offer a means o f e n h a n c i n g o u r p e r s p e c t i v e o n t h e e v o l u t i o n o f the m o d e r n d r u g d i s c o v e r y effort. G o i n g b a c k to t h e first five-year p e r i o d — 1 9 4 1 - 4 5 — t h e o v e r - a l l l e v e l of research a c t i v i t y w a s s i g n i f i c a n t l y l o w e r t h a n that of today.
M u c h of
the t e c h n o l o g y r e q u i r e d to s u p p o r t operations o f the efficiency a n d sophist i c a t i o n that are n o w c o m m o n p l a c e w a s n o t y e t a v a i l a b l e . T h e N e w D r u g A p p l i c a t i o n h a d a l r e a d y c o m e into existence a f e w years earlier, i n 1938, f o l l o w i n g t h e e l i x i r of s u l f a n i l a m i d e tragedy, a n d certification h a d b e g u n —first, w i t h i n s u l i n i n 1941 a n d s u b s e q u e n t l y w i t h p e n i c i l l i n i n 1945. I n a d d i t i o n , there w e r e t h e m a n y c o m p l i c a t i o n s t h a t t h e w a r itself i n t r o duced.
D e s p i t e a l l of this, t h e research effort o f t h e p e r i o d p r o v e d r e -
markably productive.
These were
t h e e x c i t i n g years w h e n A m e r i c a n
m e d i c i n e first g a i n e d t h e use o f antibiotics l i k e p e n i c i l l i n a n d streptom y c i n , a n d the first of the i m p r o v e d s u l f a d r u g s . R e s e a r c h at this t i m e w a s h i g h l y eclectic. an
unprecedented
Research
Chemists were applying
effort to p r o b i n g , e m u l a t i n g , a n d e x p l o i t i n g nature.
o n v i t a m i n s , a m i n o acids, a n d other n u t r i t i o n a l factors w a s
highly productive.
Efforts to i m p r o v e u p o n s u c h hormones as e p i n e p h -
Bloom and Ullyot; Drug Discovery Advances in Chemistry; American Chemical Society: Washington, DC, 1971.
8.
BLOOM
Contemporary
Drug
179
Discovery
rine, e s t r a d i o l , a n d testosterone w e r e b e g i n n i n g to b e a r f r u i t . M o l e c u l a r m o d i f i c a t i o n , w h i c h some c o n s i d e r a r e l a t i v e l y n e w f o r m of
research
endeavor, was a l r e a d y a w e l l - p r a c t i c e d art, a n d the p r e v a i l i n g s t a n d a r d of t h e r a p y that scientists sought to supersede w a s often p r e t t y l o w . E v e n at this e a r l y t i m e , i m p r o v e d analogs of m o r e t h a n a d o z e n different m a j o r classes of drugs w e r e b e g i n n i n g to b e d e v e l o p e d a n d m a r k e t e d , i n c l u d i n g the b a r b i t u r a t e h y p n o t i c s , analgesics, a n t i p y r e t i c s , l o c a l anesthetics, m u s cle relaxants, pressor amines, m e r c u r i a l d i u r e t i c s , xanthines, p a r a s y m pathomimetic
drugs,
sex
hormones,
sulfonamide
antibacterials,
and
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antimalarials. T h i s k i n d of p r o d u c t i v i t y b r o u g h t a b o u t g r o w t h i n d r u g
research
o r g a n i z a t i o n s , a n d the i n c r e a s e d l e v e l of research a c t i v i t y w a s c e r t a i n l y a c o n t r i b u t i n g factor when
major
breakthroughs
d u r i n g the e n s u i n g p e r i o d
occurred in
an
almost
(1946-50),
almost constant
stream.
W i d e s p r e a d screening of f e r m e n t a t i o n broths, p r o m p t e d b y the d r a m a t i c success of p e n i c i l l i n G , p r o d u c e d , i n r a p i d succession, the
first
three
b r o a d - s p e c t r u m a n t i b i o t i c s ( c h l o r t e t r a c y c l i n e , c h l o r a m p h e n i c o l , a n d oxyt e t r a c y c l i n e ). H o r m o n e research, e x p l o i t i n g a g r o w i n g base of k n o w l e d g e a b o u t s t e r o i d c h e m i s t r y , s u d d e n l y y i e l d e d r i c h d i v i d e n d s w i t h the d e m o n stration of the m e d i c a l i m p o r t a n c e of cortisone.
There were
notable
successes i n b o t h the search f o r i m p r o v e d analogs of e s t a b l i s h e d m e d i c i nals a n d the d i s c o v e r y of e n t i r e l y n e w d r u g classes a n d p r o t o t y p e s . first
antihistamines a p p e a r e d , as d i d the first s y n t h e t i c
The
anticholinergic
d r u g s . I s o p r o t e r e n o l was m a d e a v a i l a b l e to m e d i c a l p r a c t i c e , as w e r e the forebears of n i t r o f u r a n antibacterials, n i t r o g e n m u s t a r d s , a d r e n e r g i c , a n d g a n g l i o n i c b l o c k i n g agents, a m o n g others. E a c h n e w research t r i u m p h f o l l o w e d close u p o n the heels of the last. T h e n u m b e r of i m p o r t a n t goals for d i s c o v e r y research r e c o g n i z a b l e to m e d i c i n a l chemists a n d p h a r m a c o l o g i s t s v i r t u a l l y d o u b l e d w i t h i n a f e w short years, a n d it is h a r d l y d i f f i c u l t to a p p r e c i a t e , i n retrospect,
how
these e x h i l a r a t i n g achievements set the stage f o r the p e a k rate of p r o d u c t i n t r o d u c t i o n that o c c u r r e d a b o u t a d e c a d e later. T h e next
five-year
period (1951-55) saw a continuing parade
of
i m p o r t a n t n e w a n t i b i o t i c s p r o d u c e d d i r e c t l y b y f e r m e n t a t i o n , s u c h as p e n i c i l l i n V , n e o m y c i n , p o l y m y x i n , a n d the m e d i u m - s p e c t r u m m a c r o l i d e s . T h e massive c h e m i c a l effort m o u n t e d i n the c o r t i c o s t e r o i d field, f o l l o w i n g r e c o g n i t i o n of the m e d i c a l i m p o r t a n c e of cortisone, q u i c k l y l e d to g r e a t l y i m p r o v e d c o m p o u n d s , as first h y d r o c o r t i s o n e a n d t h e n p r e d n i s o l o n e , a t r i u m p h of a n a l o g research, b e c a m e a v a i l a b l e i n c o m m e r c i a l quantities, h e l p e d b y a major i n f u s i o n of n e w t e c h n o l o g y , the d e v e l o p m e n t of p r a c t i c a l m i c r o b i o l o g i c a l methods for effecting 11-oxygenation of the s t e r o i d nucleus.
C o m p e l l i n g e v i d e n c e that one c o u l d create v a l u a b l e synthetic
m o d i f i c a t i o n s i n the a n t i b i o t i c field also a p p e a r e d w i t h the synthesis of
Bloom and Ullyot; Drug Discovery Advances in Chemistry; American Chemical Society: Washington, DC, 1971.
180
DRUG
tetracycline
b y h y d r o g e n o l y s i s of c h l o r t e t r a c y c l i n e .
n o w , to take some of these achievements
DISCOVERY
Perhaps
we
tend,
for g r a n t e d , b u t the p a t h to
successful d i s c o v e r y i n these fields was a n y t h i n g b u t clear at the t i m e . H o w m a n y scientists w o u l d h a v e a c c u r a t e l y p r e d i c t e d i n the e a r l y 1950's that k n o w l e d g e of the r e l a t i v e l y s i m p l e structure of the a n t i b i o t i c , Chlorom y c e t i n , w o u l d not l e a d to the d i s c o v e r y of a single significant a n a l o g , w h i l e d e c i p h e r i n g the n a t u r e of o x y t e t r a c y c l i n e w o u l d u l t i m a t e l y a l l o w c h e m i c a l m o d i f i c a t i o n of that c o m p l e x , m u l t i f u n c t i o n a l m o l e c u l e to afford a n u m b e r of m e d i c a l l y u s e f u l n e w d r u g s ?
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M e a n w h i l e , the era of t r a n q u i l i z e r t h e r a p y w a s d a w n i n g as successf u l i s o l a t i o n of c r y s t a l l i n e reserpine f a c i l i t a t e d the d i s c o v e r y of its u n i q u e effects o n m e n t a l f u n c t i o n , w h i l e m o r e or less c o n c u r r e n t l y , astute c l i n i c a l research
revealed
the
then
unique
psychotherapeutic
properties
of
chlorpromazine. S t i l l other i m p o r t a n t a n d i n n o v a t i v e n e w drugs w e r e i n t r o d u c e d d u r i n g the
same p e r i o d , i n c l u d i n g the
antihypertensive
hydralazine,
a n t i - i n f l a m m a t o r y d r u g p h e n y l b u t a z o n e , the c a r b o n i c a n h y d r a s e
the
inhibi-
t o r / d i u r e t i c a c e t a z o l a m i d e , a n d i s o n i a z i d for the treatment of tuberculosis. H o w e v e r , the p e r i o d of p e a k p r o d u c t i v i t y ( 1 9 5 5 - 6 0 ) s t i l l l a y a h e a d . I n retrospect,
it is a p p a r e n t that b r e a k t h r o u g h discoveries, c a p a b l e
of
c r e a t i n g entirely n e w fields of research, w e r e no l o n g e r o c c u r r i n g freq u e n t l y , a l t h o u g h i n t r o d u c t i o n of the first o r a l c o n t r a c e p t i v e was yet to come (1957).
Instead, a m o n g the n e w p r o d u c t s i n t r o d u c e d d u r i n g this
p r o l i f i c p e r i o d a n u n u s u a l l y h i g h p e r c e n t a g e of d r u g s r e p r e s e n t e d
major
i m p r o v e m e n t s over the t h e n e x i s t i n g standards of t h e r a p y . V a l u a b l e n e w antibiotics, both direct fermentation products, and important
synthetic
m o d i f i c a t i o n s l i k e the m a c r o l i d e esters a n d the first penicillinase-resistant penicillins appeared.
I n a d d i t i o n to "the p i l l , " s t e r o i d research p r o v i d e d
a specific antagonist to the h o r m o n e , aldosterone, a n d s u p e r i o r n e w t o p i c a l corticosteroids.
Useful new
tranquilizers, including chlordiazepoxide,
a p p e a r e d , a l o n g w i t h a p r o f u s i o n of d r u g s f o r t r e a t i n g m e n t a l d e p r e s s i o n : i m i p r a m i n e a n d v a r i o u s m o n o a m i n e oxidase i n h i b i t o r s . R e s e a r c h t o w a r d n o v e l s u l f o n a m i d e d e r i v a t i v e s , a process that h a d b e g u n 20 years earlier, r e a c h e d its c u l m i n a t i o n w i t h the i n t r o d u c t i o n of two i m p o r t a n t n e w p r o t o t y p e d r u g s : the d i u r e t i c c h l o r t h i a z i d e a n d the h y p o g l y c e m i c d r u g t o l b u t a m i d e ; a host of other i n n o v a t i v e p r o d u c t s also a p p e a r e d at this t i m e , i n c l u d i n g the a n t i h y p e r t e n s i v e d r u g g u a n e t h i d i n e a n d the
antidiabetic
agent p h e n f o r m i n . Then
the
t r e n d s h i f t e d rather
abruptly.
During
the
succeeding
p e r i o d ( 1 9 6 1 - 6 5 ) the average y e a r l y rate of n e w p r o d u c t i n t r o d u c t i o n s d r o p p e d b y half.
W h a t h a p p e n e d i n the m i d s t of a p e r i o d of u n p r e c e -
d e n t e d p r o d u c t i v i t y to b r i n g about s u c h a sharp d e c l i n e ?
The
decline
set i n at just a b o u t the t i m e of the t h a l i d o m i d e t r a g e d y a n d the passage
Bloom and Ullyot; Drug Discovery Advances in Chemistry; American Chemical Society: Washington, DC, 1971.
8.
BLOOM
Contemporary
Drug
181
Discovery
of l e g i s l a t i o n r e q u i r i n g that p r o d u c t efficacy, as w e l l as safety, b e d e m o n strated t o t h e satisfaction of F D A . But what actually happened?
W e set a b o u t to t r y to a n s w e r this
q u e s t i o n b y c o m p a r i n g t h e rate of n e w p r o d u c t i n t r o d u c t i o n s b y d r u g category, f o r the five-year p e r i o d s i m m e d i a t e l y p r e c e d i n g ( 1 9 5 S - 6 2 ) a n d f o l l o w i n g (1963-67) establishment
of the n e w F D A regulations.
It is
r e a d i l y d e m o n s t r a b l e , as s h o w n b y T a b l e I I , that i n v a r i o u s w e l l - e s t a b l i s h e d d r u g categories,
where a number of adequately
u s e f u l agents
a l r e a d y existed, t h e d e v e l o p m e n t of n e w p r o d u c t s to t h e p o i n t o f o b t a i n i n g
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FDA
m a r k e t i n g a p p r o v a l either ceased altogether
or declined sharply
f o l l o w i n g i n t r o d u c t i o n of the n e w regulations. Table II.
Pre- and Post-1962 D r u g L a w Amendments
Product Category
Period
1957-62
1963-67
9 4 7 8 10 5 4 14 3
0 0 2 0 2 0 1 3 1
64
9
Antihistamines Antitussives Antispasmodics M u s c l e relaxants/antiparkinson drugs Thiazide-type diuretics Sulfonamide antibacterials Antiobesity drugs V o r t i c o s t e r o i d s (systemic a n d topical) Antinauseants Totals
Since the same p h e n o m e n o n o c c u r r e d i n a n u m b e r of other, m i n o r classifications that w e h a v e n o t a t t e m p t e d to tabulate, a p p r e c i a b l y m o r e t h a n h a l f of the d e c l i n e i n the rate of n e w p r o d u c t i n t r o d u c t i o n s that o c c u r r e d after passage of t h e 1962 a m e n d m e n t s ,
c a m e about
i n this
manner. T h e t r e n d i n three other, major d r u g categories w a s s o m e w h a t d i f ferent, h o w e v e r ( T a b l e I I I ) . I n t h e v a r i e g a t e d category, t h e n r e l a t i v e l y Table III.
Pre- and Post-1962 D r u g L a w Amendments
Product Category
Period
1957-62 Psychotherapeutic drugs tranquilizers psychostimulants Antibiotics (antibacterial, antifungal) Cancer chemotherapy Totals
16 9
25
1963-67 7 4
11
13 5
10 5
43
26
Bloom and Ullyot; Drug Discovery Advances in Chemistry; American Chemical Society: Washington, DC, 1971.
182
DRUG
n e w , c o m p r i s i n g the different types of p s y c h o t h e r a p e u t i c
DISCOVERY
d r u g s , there
was a f a l l off i n n e w p r o d u c t i n t r o d u c t i o n s , b u t not n e a r l y to the extent o b s e r v e d w i t h the m o r e exhaustively researched classes of d r u g s t a b u l a t e d above. T h e r e was v i r t u a l l y no d e c l i n e i n the i n t r o d u c t i o n of n e w antibiotics. T h i s was p a r t l y caused b y the e m e r g e n c e of a n u m b e r of i m p o r t a n t n e w semisynthetic
β-lactam a n d t e t r a c y c l i n e
compounds.
Research
in
the
p e n i c i l l i n a n d c e p h a l o s p o r i n fields h a d b e e n p r o f o u n d l y s t i m u l a t e d b y the d e v e l o p m e n t a f e w years earlier of the first p r a c t i c a l m e t h o d for
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p r e p a r i n g large quantities of 6 - a m i n o p e n i c i l l a n i c a c i d , a n d this techno l o g i c a l b r e a k t h r o u g h , a l o n g w i t h some b r i l l i a n t n e w c e p h a l o s p o r i n c h e m istry, affected the 1962-66 p e r i o d to a degree that h e l p e d offset any c o n s t r a i n i n g influence the n e w regulations m i g h t h a v e h a d . I n fact, the i n t r o d u c t i o n of i m p o r t a n t semisynthetic β-lactam p r o d u c t s l i k e a m p i c i l l i n a n d c e p h a l o t h i n i n 1963-64 has u n d o u b t e d l y s t i m u l a t e d a h i g h l e v e l of research a c t i v i t y i n those fields t h r o u g h o u t the d e c a d e a n d o n i n t o the 1970's. W i t h the c a n c e r c h e m o t h e r a p e u t i c
agents, w e are p r o b a b l y seeing
the c u m u l a t i v e effect of a joint effort o n the p a r t of government, u n i v e r s i ties, a n d the p h a r m a c e u t i c a l i n d u s t r y to c u r b this d r e a d disease.
Because
d r u g s of this t y p e t e n d , u n f o r t u n a t e l y , to have a rather n a r r o w r a n g e of usefulness, a large n u m b e r of t h e m are d e v e l o p e d . T h e t r e n d t o w a r d i n t r o d u c i n g m o r e n e w p r o d u c t s i n this category has c o n t i n u e d to present,
a n d d u r i n g 1969
the
no less t h a n three of the seven n e w drugs
m a r k e t e d i n the U . S . w e r e f o r t r e a t i n g various f o r m s of
cancer.
A s i d e f r o m a f e w situations l i k e these, the rate of n e w p r o d u c t i n t r o d u c t i o n i n this c o u n t r y has d e c l i n e d s u b s t a n t i a l l y d u r i n g the 1960's. A n analysis of the list of n e w d r u g s i n t r o d u c e d i n the U . S . b e t w e e n 1966 a n d the present c e r t a i n l y underscores this c o n c l u s i o n . agents m a d e a v a i l a b l e d u r i n g this most recent
O f the 58 b a s i c n e w
five-year
p e r i o d , no less
t h a n 41 ( 7 1 % ) w e r e for t r e a t i n g c e n t r a l nervous system i n d i c a t i o n s infectious diseases (12)
or c a n c e r ( 9 ) .
(20),
M o r e striking still, a n d certainly
m o r e v e x i n g , is the fact that d u r i n g this most recent h a l f - d e c a d e a t o t a l of o n l y seven n e w drugs w e r e i n t r o d u c e d for t r e a t i n g the host of other i m p o r t a n t c h r o n i c diseases that p l a g u e m o d e r n m a n , diseases l i k e h y p e r tension,
angina
pectoris,
r h e u m a t o i d arthritis. two
noteworthy
atherosclerosis,
diabetes,
emphysema,
and
A l t h o u g h the p e r i o d d i d see the i n t r o d u c t i o n of
l i p i d - r e g u l a t i n g drugs, t w o
valuable
diuretics,
a
β-
a d r e n e r g i c b l o c k i n g agent a p p r o v e d for t r e a t i n g c a r d i a c a r r h y t h m i a s , a n d a n o v e l agent for the treatment of gout, not one n e w d r u g for t r e a t i n g h i g h b l o o d pressure o b t a i n e d U . S . r e g u l a t o r y clearance. t h a n some d i u r e t i c s ) since 1963.
N o r has one
N o t one n e w single e n t i t y
d i l a t o r p r o d u c t has c o m e onto the U . S . m a r k e t since 1961.
(other
broncho-
( A mucolytic
Bloom and Ullyot; Drug Discovery Advances in Chemistry; American Chemical Society: Washington, DC, 1971.
8.
BLOOM
Contemporary
Drug
183
Discovery
agent i n t r o d u c e d i n 1963 is the o n l y recent single entity p u l m o n a r y d r u g . ) N o t one n e w n o n - s t e r o i d a l agent for the treatment of r h e u m a t o i d arthritis has b e e n m a d e a v a i l a b l e since
1965.
Prospects for the Future O n e c o u l d r e a c h the r a t h e r q u e s t i o n a b l e c o n c l u s i o n that the process of d i s c o v e r y of significant n e w agents i n these classes has g r o u n d to a halt, b u t a p e r u s a l of the c u r r e n t w o r l d m e d i c a l literature reveals
that
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potentially important n e w drugs have been discovered recently i n each of these classes, a n d several of these n e w d r u g s are a l r e a d y a v a i l a b l e to p h y s i c i a n s elsewhere i n the w o r l d . strong inference
that
current
T h i s makes a l l b u t u n a v o i d a b l e the
U . S . r e g u l a t o r y attitudes
governing
the
d e m o n s t r a t i o n of c l i n i c a l efficacy a n d safety r e q u i r e d f o r N D A a p p r o v a l h a v e p r o v e d so i n o r d i n a t e l y d e m a n d i n g a n d b u r d e n s o m e as to seriously i m p e d e d r u g d e v e l o p m e n t a n d stifle p r o d u c t i v i t y . C a r l D j e r a s s i , w h o h e l p e d p i o n e e r o r a l c o n t r a c e p t i v e d r u g s , has rep e a t e d l y stated i n the most c o n v i n c i n g terms that this is p r e c i s e l y w h a t has a l r e a d y h a p p e n e d i n the field of f e r t i l i t y c o n t r o l research
(2).
T h e present analysis offers other e v i d e n c e that r e g u l a t o r y factors are c o n t r i b u t i n g i m p o r t a n t l y to the s l o w d o w n . C a n it be e n t i r e l y fortuitous that n e w a n t i b i o t i c s , t r a n q u i l i z e r s , a n d c a n c e r d r u g s c o n t i n u e to g a i n F D A a p p r o v a l w i t h some r e g u l a r i t y , w h i l e n e w p r o d u c t s f o r the treatment of i m p o r t a n t , c h r o n i c m e t a b o l i c diseases are c o n s p i c u o u s o n l y b y t h e i r absence? T h o s e f a m i l i a r w i t h c l i n i c a l p h a r m a c o l o g y are w e l l a w a r e that the d i f f i c u l t y of e s t a b l i s h i n g efficacy a n d safety of a n e w
antibacterial
d r u g is i n n o w a y c o m p a r a b l e w i t h the c o r r e s p o n d i n g task i n v o l v i n g a n agent f o r the treatment of a disease l i k e a n g i n a pectoris, f o r e x a m p l e . P r o p r a n o l o l , the o n l y n e w single e n t i t y c a r d i o v a s c u l a r d r u g to r e a c h the U . S . m a r k e t d u r i n g the last three years, has yet to b e a p p r o v e d f o r use i n the treatment of a n g i n a , its m a i n a p p l i c a t i o n f o r s e v e r a l years n o w i n other m e d i c a l l y s o p h i s t i c a t e d countries l i k e the U n i t e d K i n g d o m .
Perhaps
w h a t recent events suggest is that b u r d e n s o m e regulations m a y be r e l a t i v e l y tolerable i n the t e c h n i c a l l y easier fields, b u t p r o v e to b e the " s t r a w that breaks the camel's b a c k " i n the m o r e d e m a n d i n g
fields.
W e c l e a r l y h a v e m u c h to w o r r y a b o u t w i t h r e g a r d to the effect of the present r e g u l a t o r y c l i m a t e o n the process of t r a n s l a t i n g n e w d r u g discoveries into p r o d u c t s that c a n be m a d e a v a i l a b l e to o u r h e a l t h c a r e system. H o w e v e r , it is a p p r o p r i a t e to ask also a b o u t the l i k e l y i m p a c t of the c u r r e n t regulations u p o n the process of d i s c o v e r y itself.
T h i s is a n
issue that defies rigorous analysis, b u t one c a n r e a s o n a b l y speculate
that
i n a s e l f - s t i m u l a t i n g process of the sort this s t u d y c l e a r l y suggests d r u g d i s c o v e r y research to be, any factor, s u c h as restrictive r e g u l a t i o n s , w h i c h
Bloom and Ullyot; Drug Discovery Advances in Chemistry; American Chemical Society: Washington, DC, 1971.
184
DRUG DISCOVERY
decreases t h e rate at w h i c h v i t a l n e w i n f o r m a t i o n flows f r o m t h e c l i n i c b a c k to the l a b o r a t o r y w i l l h a v e a p r o f o u n d depressant effect o n t h e rate of d i s c o v e r y . Since w e d o n o t k n o w h o w l o n g i t s h o u l d take f o r a n i m p o r tant n e g a t i v e influence o f this sort to exert its f u l l effect o n s l o w i n g d o w n the rate o f d i s c o v e r y o f i n n o v a t i v e n e w d r u g s , o n e c a n o n l y h o p e ( a n d p r a y ) that w e h a v e a l r e a d y seen the w o r s t of i t . James S h a n n o n , f o r m e r h e a d of N I H , has r e m i n d e d us r e c e n t l y that the great a n d s u b s t a n t i a l d r u g i n n o v a t i o n s of the 1940s a n d 1950s w e r e m a d e u n d e r a m o r e "laissez f a i r e " attitude of r e g u l a t o r y l a w ( 3 ) . A n
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analysis of t h e sort u n d e r t a k e n i n this p a p e r helps o n e a p p r e c i a t e h o w r a p i d l y benefits o f d r a m a t i c m a g n i t u d e a c c r u e d to society f r o m d r u g research d u r i n g that p e r i o d . A t t h e same t i m e , i t generates a c e r t a i n p e s s i m i s m about t h e f u t u r e , b y m a k i n g so c l e a r l y e v i d e n t t h e p r o f o u n d n e g a t i v e i m p a c t o n research p r o d u c t i v i t y that r e s t r i c t i v e r e g u l a t o r y atti tudes h a v e a l r e a d y h a d i n this c o u n t r y d u r i n g the b r i e f p e r i o d since 1962. J o s e p h C o o p e r o f A m e r i c a n U n i v e r s i t y , w r i t i n g o n " T h e S o c i o l o g y of I n n o v a t i o n i n M e d i c i n e , " points out that " a l l progress tends to b e i n h i b i t e d b y spontaneously a r i s i n g n e g a t i v e forces w h i c h . . . e v e n t u a l l y offset o r k i l l t h e progress w i t h w h i c h t h e y are a s s o c i a t e d " ( 4 ) . O n e c a n o n l y h o p e that society w i l l r e a l i z e q u i c k l y that i t is to its o w n great d e t r i m e n t to f a i l to p l a c e i n t o p r o p e r p e r s p e c t i v e t h e p r o b l e m s o f benefit a n d r i s k i n e v i t a b l y associated w i t h t h e d e v e l o p m e n t a n d use o f n e w d r u g s . A s this s t u d y so c l e a r l y reveals, recent progress i n m a k i n g n e w d r u g s a v a i l able f o r t r e a t i n g t h e i m p o r t a n t c h r o n i c diseases o f m a n k i n d h a s b e e n p i t i f u l l y s l o w . Society c a n i l l afford to legislate a w a y o n e o f t h e most i m p o r t a n t sources o f its o w n w e l l b e i n g .
Literature Cited (1) Paul deHaen, Inc., 11 W. 42nd Street, New York, Ν. Y. 10036. (2) Djerassi, C., Science (1969) 166, 468; (1970) 169, 941. (3) Shannon, J. Α., M.D., "The Economics of Drug Innovation," p. 83, The American University Center for the Study of Private Enterprise, Wash ington, D. C. (4) Cooper J. D., Proc. Roy. Soc. Med. (1969) 62, 48. RECEIVED
November 5, 1970.
Bloom and Ullyot; Drug Discovery Advances in Chemistry; American Chemical Society: Washington, DC, 1971.
Discussion Leland Chinn (to S. Morris K u p c h a n ) : T h e d e v e l o p m e n t of c h e m o t h e r a p e u t i c agents f r o m p l a n t sources i n the past was b a s e d m a i n l y o n f o l k l o r e a n d g e n e r a l screening p r o g r a m s .
C o u l d this a p p r o a c h b e m a d e
m o r e efficient a n d i n t e l l e c t u a l l y m o r e a p p e a l i n g b y d e v o t i n g a greater Downloaded by CORNELL UNIV on September 27, 2016 | http://pubs.acs.org Publication Date: June 1, 1971 | doi: 10.1021/ba-1971-0108.ch008
effort to u n d e r s t a n d i n g the f u n c t i o n w h i c h these agents serve plants themselves?
in
the
F o r e x a m p l e , w h a t role does reserpine p l a y in the
p l a n t that w o u l d correlate w i t h its a n t i h y p e r t e n s i v e effect i n a n i m a l s ? W h a t is the f u n c t i o n of d i g i t a l i s i n the p l a n t that w o u l d justify its use as a c a r d i o t o n i c agent? D r . Kupchan: I t h i n k it would be f a s c i n a t i n g , just as a s t u d y in basic science, to k n o w w h a t reserpine does i n r a u w o l f i a a n d d i g i t a l i s does i n foxglove, b u t I ' m not sure just h o w m u c h this w o u l d c a r r y over to the r o l e these agents p l a y i n a n i m a l tissues.
W e have h a d some
experience
i n this r e g a r d , in c o l l a b o r a t i v e efforts w i t h p l a n t physiologists a n d p l a n t pathologists to answer the q u e s t i o n as to w h a t some c o m p l e x n a t u r a l p r o d u c t s m a y be d o i n g i n the p l a n t .
I n general, it appears that p l a n t
biologists are s o m e w h a t less a d v a n c e d t h a n a n i m a l biologists i n e x p e r i m e n t a l approaches to m e c h a n i s m of action. So, in response to y o u r quest i o n , it w o u l d be most interesting to l e a r n m o r e a b o u t the f u n c t i o n of c o m p l e x p l a n t - d e r i v e d c o m p o u n d s , b u t I d o u b t that this a p p r o a c h w o u l d constitute a m o r e effective p a t h w a y to d i s c o v e r y of n e w n a t u r a l p r o d u c t s w i t h n o t e w o r t h y b i o l o g i c a l a c t i v i t y i n animals. Glenn Ullyot (to D r . K u p c h a n ) : T h e logistics of s u p p l y of a d e q u a t e quantities of p l a n t m a t e r i a l is a major factor i n seeking d r u g s f r o m p l a n t sources.
T i m e delays, expense of c o l l e c t i n g , a n d p r o b l e m s of i d e n t i f i c a -
t i o n m u s t be f a c e d . W h a t has b e e n y o u r experience w i t h these p r a c t i c a l considerations? D r . Kupchan: A c t u a l l y , w e ' v e b e e n v e r y fortunate. W e have enjoyed the close c o l l a b o r a t i o n w i t h the g r o u p u n d e r R o b e r t E . P e r d u e , Jr.,
at
the U n i t e d States D e p a r t m e n t of A g r i c u l t u r e . W h i l e there c e r t a i n l y h a v e b e e n delays a n d the logistics p r o b l e m s h a v e b e e n c o n s i d e r a b l e , not b e e n o v e r w h e l m i n g , b y a n y means. a r e l a t i v e l y accessible source
they've
I n d e e d , the p l a n t k i n g d o m offers
of c o m p o u n d s .
Certainly, plant-derived
c o m p o u n d s are less accessible t h a n synthetic p r o d u c t s , b u t they are v a s t l y m o r e accessible t h a n , for instance, p r o d u c t s f r o m m a r i n e sources. 185
Bloom and Ullyot; Drug Discovery Advances in Chemistry; American Chemical Society: Washington, DC, 1971.
186
DRUG
DISCOVERY
H . C . Caldwell (to Lloyd Conover): Please discuss p e n i c i l l i n a l l e r g i c t y p e reactions i n the c e p h a l o s p o r i n s .
Is there a crossover, a n d w h a t is
the prognosis for allergy-free c e p h a l o s p o r i n s ? D r . Conover: I'd l i k e to i n t r o d u c e m y comments w i t h the i n t r o d u c t o r y phrase, "It is m y i m p r e s s i o n that . . . ," rather t h a n c l a i m to speak f r o m the fullness of precise k n o w l e d g e . T h e r e m a y be someone here w h o can a m p l i f y w h a t I say or p o s s i b l y correct m e .
It's m y i m p r e s s i o n that the
a l l e r g i c effects w h i c h f o l l o w a d m i n i s t r a t i o n of ^ - l a c t a m a n t i b i o t i c s
are
caused b y the f o r m a t i o n of a c o v a l e n t b o n d b e t w e e n the a n t i b i o t i c or Downloaded by CORNELL UNIV on September 27, 2016 | http://pubs.acs.org Publication Date: June 1, 1971 | doi: 10.1021/ba-1971-0108.ch008
its d e g r a d a t i o n p r o d u c t a n d s e r u m p r o t e i n or tissue p r o t e i n . T h i s p e n i c i l l o y l or c e p h a l o s p o r o y l p r o t e i n is r e c o g n i z e d b y the b o d y as f o r e i g n (i.e., a n t i g e n i c ) , a n d antibodies are f o r m e d . T h e r e are r e a l l y t w o factors to be c o n s i d e r e d .
F i r s t , the c a p a b i l i t y
of a p a r t i c u l a r d r u g to cause the event w h i c h I just d e s c r i b e d , a n d sec o n d l y the c a p a b i l i t y of a d r u g a d m i n i s t e r e d to a p e r s o n i n w h i c h this process has t a k e n p l a c e to be i m m e d i a t e l y r e c o g n i z e d as a n t i g e n i c a n d to e l i c i t an a n a p h y l a c t i c r e a c t i o n . A n u m b e r of different c h e m i c a l reac tions have b e e n associated w i t h this p h e n o m e n o n . O n e of t h e m is s i m p l e a c y l a t i o n of p r o t e i n b y the ^ - l a c t a m .
I n a s m u c h as the m e c h a n i s m
of
a c t i o n of b o t h the p e n i c i l l i n s a n d c e p h a l o s p o r i n s is also t h o u g h t to i n v o l v e a c y l a t i o n b y the ^ - l a c t a m , I t h i n k that it is v e r y u n l i k e l y that there w i l l ever be a β-lactam a n t i b i o t i c w h i c h is active a n d w h i c h w i l l not i n some patients
f o r m a n t i g e n i c m a t e r i a l b y this same m e c h a n i s m .
It
is m y
i m p r e s s i o n that c e p h a l o s p o r i n s have a lesser t e n d e n c y to sensitize t h a n some p e n i c i l l i n s a n d that not a l l p e n i c i l l i n - s e n s i t i v e p e o p l e react to a g i v e n c e p h a l o s p o r i n . T h e differences are p r o b a b l y q u a n t i t a t i v e a n d w i l l never be q u a l i t a t i v e . Barry M . Bloom: I s h o u l d l i k e to address a q u e s t i o n to D r . B i e l . J o h n , as the s p o k e s m a n f o r o r g a n i c synthesis o n o u r p a n e l , y o u gave several examples of rationales that h a v e g u i d e d synthesis efforts to successful d r u g discovery, but I recall relatively little comment about total unabashedly e m p i r i c a l a p p r o a c h e s to e x p l o i t i n g the f r u i t s of the o r g a n i c chemist's l a b o r . T h i s q u e s t i o n is r e a l l y a request to t e l l it l i k e it is. W h a t percentage of successful d r u g discoveries a m o n g synthetic c o m p o u n d s d o y o u suppose is a t t r i b u t a b l e to p e o p l e w h e are just s y n t h e s i z i n g i n t e r e s t i n g structures a n d m a k i n g them available for biological evaluation i n various screening pro grams w i t h o u t a n y p a r t i c u l a r l y significant u n d e r l y i n g rationale? John Biel: A v e r y g o o d statistical analysis was d o n e d u r i n g the days of the A r m y p r o g r a m o n i n c a p a c i t a t i n g d r u g s , a n d those p r o g r a m s that w e r e b a s e d o n b l i n d screening of c h e m i c a l s y i e l d e d about three active c o m p o u n d s i n 10,000 w h i l e m i s s i o n - o r i e n t e d t y p e d r u g research d u c e d p r o b a b l y 10 active c o m p o u n d s p e r 3000.
Bloom and Ullyot; Drug Discovery Advances in Chemistry; American Chemical Society: Washington, DC, 1971.
pro
187
DISCUSSION
D r . Bloom: T h i s is r e a l l y an interesting q u e s t i o n to a lot of us, I t h i n k . M o r r i s , w o u l d y o u l i k e to c o m m e n t o n it? D r . Kupchan: I w o u l d suggest m o d i f i c a t i o n of J o h n B i d ' s o t h e r w i s e v e r y b e a u t i f u l slide c o n c e r n i n g " r a t i o n a l d r u g d e s i g n " i n the d i s c o v e r y of n e w drugs. S p e c i f i c a l l y , a clear d i s t i n c t i o n s h o u l d b e d r a w n b e t w e e n the l i m i t e d past c o n t r i b u t i o n s of r a t i o n a l d r u g d e s i g n to the d i s c o v e r y of n e w s t r u c t u r a l prototypes, a n d , i n contrast, the extensive c o n t r i b u t i o n s to the m o l e c u l a r m o d i f i c a t i o n of p r o t o t y p e d r u g s . A c r i t i c a l r e v i e w of the literature reveals that the vast m a j o r i t y of p r o t o t y p e d r u g s i n v a r i o u s
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areas have c o m e f r o m systematic screening a n d / o r fortuitous a n d serend i p i t o u s d i s c o v e r y rather t h a n f r o m r a t i o n a l d e s i g n f r o m first p r i n c i p l e s . W o u l d n ' t y o u agree, J o h n , that, i n fact, r a t i o n a l d r u g d e s i g n has p l a y e d a f a r greater role i n the m o l e c u l a r m o d i f i c a t i o n of p r o t o t y p e s t h a n i n the d i s c o v e r y of n e w prototypes? D r . Biel: I t h i n k that s e r e n d i p i t y has to be p l a n n e d . U n l e s s y o u h a v e a research person w h o is p r i m e d to m a k e a d i s c o v e r y , he w i l l not m a k e a d i s c o v e r y . T h e r e are other factors that p l a y into the h a n d s of s e r e n d i p i t y ; that's one i t e m I h a d to leave out because of the pressure of time, b u t a d r u g d i s c o v e r y is r e a l l y s o m e t h i n g relative.
T h e t e r m d i s c o v e r y is r e l a -
tive i n the sense that other d i s c i p l i n e s h a v e to b e r e a d y to r e c o g n i z e the discovery. I t h i n k L i b r i u m a n d V a l i u m are prefect examples of that thesis; h a d they b e e n d i s c o v e r e d 20 to 30 years earlier, neither the m e d i c a l , c u l t u r a l , nor s o c i o l o g i c a l c l i m a t e w o u l d h a v e b e e n r e a d y to s t a m p this
finding
as
a major d i s c o v e r y . T h e c o n c e p t of t r e a t i n g anxiety b e c a m e r e a l l y f a s h i o n a b l e after the w o r l d w a r . It was the a c c e p t a n c e b y the m e d i c a l p r o f e s s i o n a n d the a d m i s s i o n b y the p a t i e n t that he is anxious that c o n t r i b u t e d to the d i s c o v e r y of anti-anxiety drugs. So i n answer to D r . K u p c h a n ' s question, I t h i n k there are factors
many
that n e e d to be i n t e g r a t e d for a p e r s o n to b e c o m e i n t u i t i v e .
Y o u ' r e not just i n t u i t i v e because you're b o r n that w a y , b u t i t does r e q u i r e a k n o w l e d g e of a c e r t a i n n u m b e r of facts that n e e d to b e
integrated
into m a k i n g a d i s c o v e r y . D r . Bloom: C h e t , d o y o u h a v e a c o m m e n t o n this question? Chester Cavallito: A s w i t h m a n y differences of o p i n i o n , the differences are m o r e s e m a n t i c a l l y b a s e d t h a n issue based. b y rational?
W h a t do w e mean
I don't b e l i e v e y o u r q u e s t i o n has b e e n a n s w e r e d
satisfac-
t o r i l y because w e ' r e not a l l u s i n g the t e r m r a t i o n a l i n the same sense. D r . Bloom: O n the a s s u m p t i o n that some of y o u i n the a u d i e n c e m a y feel q u i t e strongly o n the subject, is there anyone else w h o w o u l d l i k e to make a brief comment? Saul Neidleman: I t h i n k i n one sense the t w o d i s t i n g u i s h e d panelists h a v e b e e n c o m p a r i n g peaches a n d apples.
It is one t h i n g to talk a b o u t
Bloom and Ullyot; Drug Discovery Advances in Chemistry; American Chemical Society: Washington, DC, 1971.
188
DRUG DISCOVERY
10,000 p u r e c o m p o u n d s a n d q u i t e another t h i n g to t a l k a b o u t 300
fer-
m e n t a t i o n broths or 300 p l a n t extracts w h e r e y o u r e a l l y don't k n o w h o w m a n y c o m p o u n d s are i n v o l v e d . I w o u l d suggest that y o u c o u l d , b y m a k i n g a p p r o p r i a t e mixtures of 10,000 c o m p o u n d s , b e a b l e to w o r k
the
statistics to y o u r a d v a n t a g e to m a k e it l o o k as t h o u g h r a n d o m s c r e e n i n g is better t h a n r a t i o n a l screening. I w o u l d agree that it is m o r e a s e m a n t i c d i f f i c u l t y t h a n a n y t h i n g else.
Y o u h a v e to define p r e c i s e l y w h a t i t is
y o u ' r e t e s t i n g — p r e c i s e l y w h a t i t is y o u ' r e l o o k i n g a t — o r else the questions a n d answers h a v e r e l a t i v e l y little m e a n i n g .
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James McFarland (to William P u r c e l l ) : T h e r e is a n a i r of m y s t i c i s m i n the use of m o l e c u l a r o r b i t a l parameters. parameters
D o y o u f e e l that
these
relate to b i o l o g i c a l processes that w e are a l r e a d y f a m i l i a r
w i t h or d o t h e y p e r h a p s relate to s o m e t h i n g w e d o n ' t yet u n d e r s t a n d a b o u t h o w d r u g s act? If it is the f o r m e r , w o u l d y o u elaborate o n h o w w e m i g h t i n t e r p r e t successful correlations w i t h s u c h terms as
"highest
occupied molecular orbital," "lowest unoccupied molecular orbital," and "frontier orbital"? D r . Purcell: A c t u a l l y , there is a b l a c k box a r o u n d the m o l e c u l a r orbital calculations.
T h i s is w h y I p u r p o s e l y t h r e w the w h o l e t h i n g
together this a f t e r n o o n to t r y to m a k e it clear that there s h o u l d n ' t b e this distinction, i n m y m i n d anyway, between a calculated parameter
and
one w h i c h is m e a s u r e d . W i t h r e g a r d to the correlations a n d t h e i r m e a n i n g , i f one suspects that e l e c t r o n - d o n a t i n g properties are i m p o r t a n t , one m i g h t l o o k f o r correlations w i t h the energies of the highest o c c u p i e d m o l e c u l a r orbitals. y o u measure
A n d I d o n ' t t h i n k it makes a n y difference w h e t h e r
this p o l a r o g r a p h i c a l l y or w h e t h e r y o u c a l c u l a t e
molecular orbital calculations.
it f r o m
If the p a r a m e t e r is there a n d it is sig-
nificant a n d it is a factor i n the b i o l o g i c a l process, I t h i n k it is q u i t e l e g i t i m a t e to correlate it.
Y o u h a v e to r e l y o n statistics to
determine
w h e t h e r there is a c o r r e l a t i o n or not. I h a d a q u e s t i o n the other d a y , " Y o u k n o w w h a t I ' d l i k e to d o , I'd l i k e to see a H a n s c h analysis o n a series of c o m p o u n d s a n d t h e n I ' d l i k e to see some m o l e c u l a r o r b i t a l calculations o n the same series." T h e p o i n t is that y o u don't c o m p a r e this t y p e of c o r r e l a t i o n w i t h that t y p e of correl a t i o n i n this sense.
R a t h e r I t h i n k it is m o r e i m p o r t a n t to l o o k at a
p a r t i c u l a r m o d e l a n d t h e n use w h a t e v e r t e c h n i q u e s y o u n e e d to get the parameters
that go into that m o d e l , w h e t h e r y o u measure
the d i p o l e
m o m e n t or w h e t h e r y o u c a l c u l a t e it f r o m w a v e f u n c t i o n s or w h e t h e r y o u take the c h a r g e densities f r o m pK measurements or w h e t h e r y o u c a l c u l a t e the c h a r g e density.
It is not the H a n s c h m o d e l vs. m o l e c u l a r orbitals.
T h a t makes no sense to me. R a t h e r it is u s i n g m o l e c u l a r o r b i t a l c a l c u l a tions to get at f u n d a m e n t a l properties of the m o l e c u l e s — t h e same w a y that y o u w o u l d get at t h e m if y o u m e a s u r e d the i n f r a r e d a b s o r p t i o n of
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189
DISCUSSION
the c a r b o n y l to get at the stretch f r e q u e n c y a n d t h e n use that d a t u m i f it has a n y m e a n i n g i n the m o d e l f o r the c o r r e l a t i o n . D r . Bloom: I n v i e w of the w a y that w e h a v e s o l i c i t e d questions f o r the p a n e l , i t is o b v i o u s that the a u d i e n c e hasn't h a d m u c h of a c h a n c e to s u b m i t a n y t h i n g w i t h r e g a r d to the last f e w papers, b u t let m e i n v i t e c o m m e n t s or questions f r o m the floor w i t h r e g a r d to D r . Burns's p a p e r . A r e there a n y questions for J o h n ? D r . Ullyot: J o h n , y o u t a l k e d a b o u t setting u p the institute i n w h i c h you're g o i n g into the i n v e s t i g a t i o n of b a s i c b i o l o g y . D o y o u t h i n k that i n Downloaded by CORNELL UNIV on September 27, 2016 | http://pubs.acs.org Publication Date: June 1, 1971 | doi: 10.1021/ba-1971-0108.ch008
itself w i l l l a y the basis f o r r a t i o n a l d e s i g n of d r u g s , or is it a source of k n o w l e d g e of b i o l o g i c a l systems w h i c h w e c a n c o n t r o l a n d influence a n d use i n s e e k i n g n e w d r u g s ? John J. Burns: T h e first t h i n g I s h o u l d say is that the d r u g d e v e l o p ment procedure should have proper balance.
W e hear a lot a b o u t b a s i c
vs. a p p l i e d research, a n d it is v e r y h a r d f o r m e to define w h a t is b a s i c a n d w h a t is a p p l i e d . W h a t is b a s i c t o d a y m a y be a p p l i e d t o m o r r o w , or vice-versa.
It w o u l d be a serious m i s t a k e to go o v e r b o a r d o n a n y one
specific t y p e of a p p r o a c h . T h e r e are c e r t a i n things w h i c h w e find most e x c i t i n g , a n d the fact that w e find t h e m most e x c i t i n g p e r h a p s
means
that they s h o u l d b e most p r o d u c t i v e . M y o w n f e e l i n g o n the subject is that i f one is g o i n g to h a v e a b r o a d l y b a s e d d r u g d e v e l o p m e n t p r o g r a m , one must have a g o o d b a l a n c e b e t w e e n b a s i c a n d a p p l i e d research. T h e q u e s t i o n of r a n d o m s c r e e n i n g came u p earlier.
When I
first
w e n t i n t o i n d u s t r y I was v e r y s k e p t i c a l a b o u t r a n d o m screening.
I
t h o u g h t it a waste of t i m e a n d effort to m a k e thousands of c o m p o u n d s a n d t h e n to screen t h e m b y thousands a n d thousands of tests.
There
must be a better w a y , or to use a better t e r m , a m o r e r a t i o n a l w a y of finding
a n e w d r u g . B u t I t h i n k it w o u l d be a m i s t a k e o n the p a r t of a n y
d r u g d e v e l o p m e n t o r g a n i z a t i o n to d o a w a y w i t h r a n d o m screening.
One
doesn't h a v e to justify r a n d o m s c r e e n i n g because it has c e r t a i n l y g i v e n us leads, b u t to m a k e it p a y , y o u h a v e to h a v e g o o d biologists, a n d t h e y n e e d a p r o p e r scientific e n v i r o n m e n t to c a r r y out t h e i r w o r k . I n the o l d days at the N I H t h e y w o u l d say " n o w w h y don't w e set u p d r u g testing facilities for m e d i c i n a l chemists w h o h a p p e n to be s y n t h e s i z i n g c o m p o u n d s u n d e r N I H grants so that w e c a n get together
a
lot of b i o l o g i c a l d a t a so w e ' l l k n o w w h a t these c o m p o u n d s are d o i n g . " I a l w a y s t h o u g h t this w o u l d be a waste of t i m e because to m a k e r a n d o m s c r e e n i n g w o r k , y o u must h a v e the necessary p h a r m a c o l o g i c a l b a c k - u p . If a c o m p o u n d shows a n i n t e r e s t i n g p h a r m a c o l o g i c effect i n an a n i m a l , y o u have to h a v e g o o d biologists a r o u n d to s t u d y it. F u r t h e r m o r e , y o u must have g o o d f e e d b a c k to the chemists.
If y o u don't h a v e g o o d f e e d -
back, biologists-to-chemists, a n d chemists-to-biologists, a n d have t h e m i n
Bloom and Ullyot; Drug Discovery Advances in Chemistry; American Chemical Society: Washington, DC, 1971.
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DRUG DISCOVERY
a p o s i t i o n w h e r e t h e y c a n t a l k to each other, y o u ' r e not g o i n g to h a v e the proper environment. G e t t i n g to y o u r q u e s t i o n a b o u t the d e v e l o p m e n t of a n Institute, there are a lot of things w e don't k n o w , a n d i n o r d e r to k n o w these t h i n g s , we're g o i n g to h a v e to take a r e l a t i v e l y l o n g range a p p r o a c h . I m e n t i o n e d i n m y presentation the q u e s t i o n of l o o k i n g for a n e w d r u g f o r v i r u s disease, b u t i f y o u l o o k at the effort w h i c h has gone i n t o v i r a l r e s e a r c h over the past 20 years a n d the p r o d u c t of this effort, it's r a t h e r d i s c o u r aging.
O n e of o u r p r o b l e m s is that w e don't k n o w e n o u g h a b o u t
the
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q u e s t i o n of v i r a l r e p l i c a t i o n , h o w c h e m i c a l s m a y interfere w i t h p e n e t r a t i o n of v i r u s i n t o cells, etc. balance between approach)
W h a t w e n e e d is a p r o g r a m w h i c h a l l o w s a
b a s i c research
( i n the sense of a m o l e c u l a r b i o l o g y
a n d a p p l i e d research
a l o n g w i t h g o o d chemists
and good
biologists, w h o are i n a p o s i t i o n to d o the necessary e v a l u a t i o n . D r . Cavallito (to D r . B u r n s ) : W e ' v e h e a r d a great d e a l a b o u t m o l e c u l a r b i o l o g y i n the last decade.
W h e n I r e a d the journals, I find i t
h a r d to d i s t i n g u i s h this f r o m n u c l e i c a c i d c h e m i s t r y .
I am wondering,
J o h n , if y o u c o u l d t e l l us w h a t is y o u r c o n c e p t of m o l e c u l a r b i o l o g y , w h i c h p e r h a p s is b r o a d e r t h a n n u c l e i c a c i d c h e m i s t r y , a n d h o w
that
differs f r o m w h a t was t e r m e d b i o c h e m i s t r y 15 or 20 years ago? D r . Burns: T h e t e r m " m o l e c u l a r b i o l o g y " w a s c o i n e d a n u m b e r of years back.
Institutes of m o l e c u l a r b i o l o g y h a v e b e e n set u p i n v a r i o u s
universities a n d n e w d e p a r t m e n t s of m o l e c u l a r b i o l o g y i n m e d i c a l schools. T h e major emphasis i n m o l e c u l a r b i o l o g y is o n n u c l e i c a c i d
research,
a l t h o u g h m o r e b r o a d l y it is the s t u d y of b i o l o g i c a l processes at a m o l e c u lar
level,
and
I
would
certainly
not
try
to
d i s t i n g u i s h that
from
biochemistry. A . A . Larsen: I sometimes r e g a r d the issue of b i o l o g i c a l k n o w l e d g e as a cop-out.
F r o m w h a t J o h n B i e l has s a i d earlier, there are
many
examples of d r u g s w h i c h w e r e d i s c o v e r e d b e f o r e w e w e r e f u l l y a w a r e of the details of t h e i r m e c h a n i s m . T h e r e is p e r h a p s a l i n k b e t w e e n the suggested b i o l o g i c a l g a p a n d the situation B a r r y just m e n t i o n e d r e g a r d i n g the great effort necessary to get a m e d i c a m e n t t h r o u g h the F D A . I h a v e k n o w n biologists, w h o i f g i v e n the chance, w o u l d go a w a y f o r 20 years to investigate one c h e m i c a l i n one p a r t i c u l a r b i o l o g i c a l system. Question from the floor (to Bernard R. Belleau): I n c o n n e c t i o n w i t h t h r e e - d i m e n s i o n a l m o l e c u l e structure, i f one obtains
d a t a u s i n g x-ray
c r y s t a l l o g r a p h y or some other t o o l , c a n y o u a p p l y these data d i r e c t l y to systems w h e r e the d r u g is u s e d i n s o l u t i o n or in vivo? tions, i n t e r a t o m i c
distances,
a n d b o n d angles
under
D o the c o n f o r m a such
conditions
c o r r e s p o n d to the c r y s t a l l i n e state? D r . Belleau: T h e r e are a n u m b e r of examples w h e r e i n the tertiary structure is k n o w n t h r o u g h x-ray c r y s t a l l o g r a p h y , a n d i t appears that i n
Bloom and Ullyot; Drug Discovery Advances in Chemistry; American Chemical Society: Washington, DC, 1971.
191
DISCUSSION
s o l u t i o n the a c t i v e site at least seems to r e t a i n m a n y of the same p r o p e r ties. H o w e v e r , there is also o p p o s i t e e v i d e n c e t h a t i n s o l u t i o n i n t e r a c t i o n s w i t h the solvent w i l l m o d i f y the structure a p p r e c i a b l y .
N o w the b i g
q u e s t i o n a l w a y s arises w h e n w o r k i n g w i t h p u r e e n z y m e s or p u r e p r o teins as m o d e l s : are y o u not f u r t h e r f r o m r e a l i t y the p u r e r y o u r substances are? W h e n w e are u s i n g a n e n z y m e i n s o l u t i o n , w e h a v e e v i d e n c e that its s p e c i f i c i t y w i l l d e p e n d u p o n its state of a g g r e g a t i o n . differ w h e n it is a t t a c h e d say to a m e m b r a n e .
T h i s w i l l also
T h e r e are changes w h i c h
o c c u r that are q u i t e serious, a n d this is a field f o r f u t u r e research.
We
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are just b e g i n n i n g to a p p r e c i a t e the m a g n i t u d e of the p r o b l e m . Paul Craig (to D r . P u r c e l l ) : T o c o n t i n u e a l o n g the same l i n e , is not w h a t w e just s a i d e v e n d o u b l y true f o r q u a n t u m m e c h a n i c a l c a l c u l a t i o n s , w h i c h i n essence c a l c u l a t e a m o l e c u l e i n i s o l a t i o n ? D r . Purcell: There's no a r g u m e n t a b o u t that.
I w o n ' t t r y to d e f e n d
the w o r k that K i e r is d o i n g . If he w e r e here, I ' m sure h e ' d h a v e s o m e t h i n g to say a b o u t it. H i s p o i n t is that i n d o i n g these c a l c u l a t i o n s y o u h a v e to start s o m e w h e r e , a n d y o u start w i t h a n i s o l a t e d m o l e c u l e , a n d y o u r e c o g n i z e that that m o l e c u l e is i n q u i t e a different e n v i r o n m e n t i n the b i o l o g i c a l system, b u t that's i n b o l d face t y p e at the b e g i n n i n g — t h e r e ' s n o a t t e m p t to say y o u ' r e d o i n g the c a l c u l a t i o n i n a b i o l o g i c a l e n v i r o n m e n t . D r . Cavallito: I w a n t to ask a q u e s t i o n of o u r c h a i r m a n r e l a t i v e to his
v e r y fine c l o s i n g p r e s e n t a t i o n .
B e t w e e n 1938
a n d 1962
the F D A
officially h a d the statutory basis f o r r e q u i r i n g e v i d e n c e of safety.
How-
ever, those i n d i v i d u a l s w h o dealt w i t h the F D A are q u i t e a c q u a i n t e d w i t h the fact that a b o u t 1960, i n other w o r d s t w o years b e f o r e the
1962
a m e n d m e n t s , there w a s a n i m p l i e d request f o r e v i d e n c e of efficacy o n the basis of the a r g u m e n t that safety i n the absence of efficacy w a s meaningless. N o w let's project that i n t o o u r present state. T h e '62 statute specifically d i d n o t g i v e the F D A a u t h o r i t y to request c o m p a r a t i v e efficacy. H o w e v e r , there are some g r u m b l i n g s that p e r h a p s w e are b e g i n n i n g to see the b e g i n n i n g of this k i n d of r e q u i r e m e n t . D o y o u h a v e a n y c o m ments o n that a n d w h a t that w o u l d d o to the d r u g i n n o v a t i o n process? D r . Bloom: Y o u p u t it e u p h e m i s t i c a l l y , i n m y o p i n i o n . I t h i n k there are a n u m b e r of f a m i l i a r examples that are h a r d to i n t e r p r e t i n other w a y s t h a n that the F D A is b e g i n n i n g to c o n c e r n itself w i t h matters of r e l a t i v e efficacy. Frank Weisenborn: I n D r . Biel's d i s c u s s i o n of the r a t i o n a l a p p r o a c h , I s t i l l don't t h i n k a n y o n e has r e a l l y s a i d h o w it is or p u t it a l l together. I t h i n k it is a m i x t u r e of r a t i o n a l i t y a n d h o p e i n that i n m a n y fields of m e d i c i n a l c h e m i s t r y w e l o o k f o r the s o p h i s t i c a t e d o r g a n i c c h e m i s t b u i l d a n e w h e t e r o c y c l i c m o l e c u l e because
to
w e w a n t to b u i l d a b r o a d
p r o t e c t i o n i n terms of a patentable area, a n d t h e n w e l o o k f o r a n e x p e r i e n c e d m e d i c i n a l c h e m i s t to a t t a c h the a p p r o p r i a t e side chains.
Bloom and Ullyot; Drug Discovery Advances in Chemistry; American Chemical Society: Washington, DC, 1971.
It is a
192
DRUG DISCOVERY
m i x t u r e of r a t i o n a l i t y a n d h o p e , b u t w e d o l o o k m o r e t o w a r d s the econ o m i c side t h a n w a s expressed b y m e m b e r s of the p a n e l . John Fried: It's d i f f i c u l t to a d d a n y t h i n g r e a l l y significant to the v e r y excellent thesis p r e s e n t e d b y D r . B l o o m a b o u t the rate of c o n t e m p o r a r y d r u g d i s c o v e r y , b u t one p o i n t m i g h t be m a d e w h i c h makes his analysis even m o r e w o r r i s o m e . If one considers that the rate of d r u g d i s c o v e r y has decreased b y a factor of 3 a n d expenditures h a v e gone u p b y at least a factor of 2, the average cost of d e v e l o p m e n t of a n e w d r u g has i n c r e a s e d b y a p p r o x i m a t e l y a factor of 6.
N o w i f one extends this analysis, the
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t i m e m a y not be too f a r a w a y before p h a r m a c e u t i c a l c o m p a n i e s
decide
that t h e i r r e t u r n o n i n v e s t m e n t for f u n d s spent i n research are s u c h that those f u n d s m i g h t v e r y w e l l be spent elsewhere.
T h i s is o b v i o u s l y a most
u n f o r t u n a t e c o n c l u s i o n , b u t it is s o m t h i n g that needs to be b o r n e i n m i n d w h e n w e talk a b o u t d r u g d i s c o v e r y . D r . Bloom: T h i s is c e r t a i n l y a n i m p o r t a n t c o m m e n t , a n d I ' m sure, J o h n , y o u w o u l d d i r e c t people's attention i n this r e g a r d to the a r t i c l e b y C a r l D j e r a s s i i n Science
recent
w h i c h offers some s t a r t l i n g t i m e a n d
cost projections f o r the d e v e l o p m e n t of n e w o r a l c o n t r a c e p t i v e John Topliss: I ' d l i k e to c o m m e n t o n y o u r excellent
agents.
presentation.
W h i l e I c e r t a i n l y agree w i t h the thrust of y o u r conclusions, I w o n d e r i f y o u p e r h a p s s i d e - s t e p p e d one p a r t of the analysis w h i c h a d m i t t e d l y is very difficult but w h i c h w o u l d have made your conclusions a little more rigorous.
O n e s h o u l d t r y to estimate the i n d i v i d u a l w o r t h of the d r u g
discoveries w h i c h y o u m e n t i o n e d o n l y i n terms
of n u m b e r s .
In
one
p e r i o d y o u h a d , I t h i n k , 39 n e w entities, b u t w e a l l k n o w i n t h a t p e r i o d m a n y of t h e m w e r e r e l a t i v e l y m i n o r m o d i f i c a t i o n s .
O n e r e a l l y has to
estimate w h a t e a c h d r u g a d d s to the t o t a l v a l u e of t h e r a p y i n t h a t area i n o r d e r to m a k e a f a i r c o m p a r i s o n of the i m p a c t o n m e d i c i n e as a w h o l e . P e r h a p s one m i g h t c o m e u p w i t h the same sort of answers i n this m o r e r i g o r o u s analysis, b u t p e r h a p s the results m i g h t not h a v e l o o k e d so i m pressive i n terms of the changes w h i c h h a v e t a k e n p l a c e . D r . Bloom: A s far as I ' m c o n c e r n e d y o u r c o m m e n t s are f a i r l y t a k e n . I d o t h i n k , h o w e v e r , that m y m a i n thesis w o u l d not b e d i s p r o v e d b y an analysis of that sort.
O u r efforts so f a r stimulate m e to w a n t to t r y to
d o exactly the sort of t h i n g that y o u ' r e t a l k i n g about, b u t I h a v e w a t c h e d others t r y , a n d I've t r i e d a l i t t l e b i t myself. So far, I just don't see a w a y to d o the analysis o b j e c t i v e l y .
It's w o r t h t h i n k i n g about, a n d I
hope
others w i l l a t t e m p t s u c h a n analysis themselves. Robert Cox: Just a c o m m e n t , B a r r y , o n y o u r remarks a n d those of C h e t C a v a l l i t o r e g a r d i n g the present a t t i t u d e of the F D A t o w a r d N e w D r u g A p p l i c a t i o n s . I c e r t a i n l y agree that there is the i m p l i c a t i o n of r e l a t i v e efficacy, not just efficacy p e r se i n some N A S - N R C dations a n d subsequent F D A decisions.
recommen-
I t h i n k t h a t the F D A is o f t e n
Bloom and Ullyot; Drug Discovery Advances in Chemistry; American Chemical Society: Washington, DC, 1971.
193
DISCUSSION
m a k i n g judgments
based
upon comparative
therapeutic
ratios
a n d is
m o v i n g t o w a r d rejection of some N D A submissions i f s u c h cannot justified via
be
a m o r e attractive t h e r a p e u t i c r a t i o t h a n that of p r o d u c t s
a l r e a d y m a r k e t e d for p e r t i n e n t i n d i c a t i o n s . D r . Bloom: D r . U l l y o t , d o y o u w a n t to c o m m e n t o n that? D r . U l l y o t : O n t h e next p a n e l w e l l h a v e a n F D A m a n here, a n d I h o p e some of these questions w i l l b e r a i s e d then.
P e r h a p s i t is a l i t t l e
u n f a i r to go i n t o these questions v e r y extensively w i t h o u t g i v i n g h i m a c h a n c e to hear t h e m .
I ' d r e a l l y l i k e to h a v e h i m c o m m e n t as a repre-
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sentative of the F D A . D r . Bloom: D r . C o n o v e r , w h a t d o the results of y o u r q u e s t i o n n a i r e or a n y other i n f o r m a t i o n that y o u m a y have suggest w i t h r e g a r d to the present l e v e l of research a c t i v i t y d i r e c t e d to finding n e w antibiotics a n d f e r m e n t a t i o n broths?
H a s this k i n d of research d e c l i n e d i n the last 10
years a n d w i l l it d e c l i n e i n the f u t u r e ? D r . Conover: O n e of the illustrations that I presented c a r r i e d c u m u lative totals t h r o u g h 1965,
a n d to that p o i n t the t o t a l n u m b e r of n e w
antibiotics r e p o r t e d for a
five-year
Dr.
p e r i o d h a d c o n t i n u e d to
P e r l m a n of W i s c o n s i n has a s u m m a r y w h i c h extends,
1968.
increase.
I t h i n k , to
T h i s makes it a p p e a r that there has b e e n a l e v e l l i n g off, b u t at a
m u c h h i g h e r l e v e l t h a n that of the 1940's a n d 1950's. T h e t o t a l n u m b e r of n e w a n t i b i o t i c entities r e p o r t e d has not d r o p p e d to a l e v e l that is l o w c o m p a r e d w i t h the p e r i o d w h e n i m p o r t a n t discoveries w e r e b e i n g m a d e at a m u c h faster rate.
I w o u l d l i k e to t h i n k that b y b r o a d e n i n g
the target, as I t r i e d to suggest i n m y talk, activities d i r e c t e d t o w a r d finding
d r u g s of m o r e different k i n d s f r o m m i c r o b i o l o g i c a l sources
will
increase. D r . Bloom: W e w i l l close b y a s k i n g D r . B u r n s to r e s p o n d to a question f r o m D r . L a u g h l i n : " M o d e r n drugs a i m to increase the l e v e l of w e l l b e i n g of i n d i v i d u a l organisms, e s p e c i a l l y those w h o c o u l d not o t h e r w i s e f u n c t i o n or s u r v i v e i n their e n v i r o n m e n t .
Is this g o a l t r u l y
w i t h the best interests of f u t u r e m e m b e r s of the
consistent
species?"
D r . Burns: B r i e f l y , I t h i n k w e are f a c e d w i t h c e r t a i n e t h i c a l c o n s i d erations.
If w e are able i n the next 10, 15, or 20 years to extend l i f e f o r
another 10 or 20 years, or p e r h a p s to a l l o w p e o p l e to l i v e w h o n o r m a l l y w o u l d d i e n o w w i t h genetic disease, b u t p e r h a p s to l i v e i n a w a y that w o u l d be i n c o m p a t i b l e w i t h a g o o d life, are w e d o i n g s o m e t h i n g good? I w o u l d say that this is the t y p e of q u e s t i o n I w o u l d rather see p o s e d to a p a n e l of p h i l o s o p h e r s , theologians, a n d m e d i c a l p e o p l e . T h e r e is another q u e s t i o n w h i c h has c o m e u p that relates to
the
F D A , a n d I w o u l d l i k e to c o m m e n t o n it. W e get ourselves i n t o t r o u b l e if w e t e n d to t h i n k that this p r o b l e m is b a s i c a l l y one i n g e t t i n g a n e w d r u g a p p r o v e d . T h e r e is another v e r y i m p o r t a n t issue here.
W h e n we
Bloom and Ullyot; Drug Discovery Advances in Chemistry; American Chemical Society: Washington, DC, 1971.
194
DRUG
DISCOVERY
l o o k at the 1950's there w e r e c e r t a i n things that w e d i d i n the b i o l o g i c a l testing of n e w d r u g s i n terms of t o x i c i t y , etc., b u t n o w w e m u s t d o m u c h more. It is not just that the F D A is t e l l i n g us to d o these things, b u t w e h a v e to d o t h e m because the w h o l e l e v e l of m e d i c a l science has a d v a n c e d . T h e d o c t o r is e x p e c t i n g m o r e i n f o r m a t i o n o n d r u g s . T h e m e d i c a l students are b e i n g t a u g h t a different k i n d of p h a r m a c o l o g y t h a n they w e r e
10
years ago. T h e t y p e of i n f o r m a t i o n w e h a v e to s u p p l y o n drugs is m u c h m o r e costly, a n d it is o b v i o u s l y g o i n g to have a n effect o n the d e v e l o p m e n t process.
It is not just a question of the F D A g i v i n g us p r o b l e m s
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i n r e q u i r i n g n e w tests, b u t the tests m u s t be d o n e to satisfy o u r o w n feelings o n w h a t is necessary for a d e q u a t e b i o l o g i c a l i n f o r m a t i o n o n a new drug. Dr.
B l o o m : O n e of the m a i n thrusts, if not the m a i n thrust, of m y
a r g u m e n t is that a n y t h i n g w h i c h serves to i m p e d e the rate at w h i c h n e w k n o w l e d g e is generated i n c l i n i c a l p h a r m a c o l o g y is b o u n d i n the e n d to suppress the w h o l e process.
So r e a l l y w e r e b o t h a r g u i n g f o r the n e e d
for more knowledge.
Bloom and Ullyot; Drug Discovery Advances in Chemistry; American Chemical Society: Washington, DC, 1971.