Drug Annotation pubs.acs.org/jmc
Discovery of (R)‑1-(3-((2-Chloro-4-(((2-hydroxy-2-(8-hydroxy-2-oxo1,2-dihydroquinolin-5-yl)ethyl)amino)methyl)-5methoxyphenyl)amino)-3-oxopropyl)piperidin-4-yl [1,1′-Biphenyl]-2ylcarbamate (TD-5959, GSK961081, Batefenterol): First-in-Class Dual Pharmacology Multivalent Muscarinic Antagonist and β2 Agonist (MABA) for the Treatment of Chronic Obstructive Pulmonary Disease (COPD) Adam D. Hughes,*,† Yan Chen,† Sharath S. Hegde,‡ Jeffrey R. Jasper,∥ Sarah Jaw-Tsai,§ Tae-Weon Lee,∥ Alexander McNamara,‡ M. Teresa Pulido-Rios,‡ Tod Steinfeld,∥ and Mathai Mammen† Departments of †Medicinal Chemistry, ‡Pharmacology, §Drug Metabolism and Pharmacokinetics, and ∥Molecular and Cellular Biology, Theravance Biopharma, Inc., 901 Gateway Boulevard, South San Francisco, California 94080, United States S Supporting Information *
ABSTRACT: Through application of our multivalent approach to drug discovery we previously reported the first discovery of dual pharmacology MABA bronchodilators, exemplified by 1. Herein we describe the subsequent lead optimization of both muscarinic antagonist and β2 agonist activities, through modification of the linker motif, to achieve 24 h duration of action in a guinea pig bronchoprotection model. Concomitantly we targeted high lung selectivities, low systemic exposures and identified crystalline forms suitable for inhalation devices. This article culminates with the discovery of our first clinical candidate 12f (TD5959, GSK961081, batefenterol). In a phase 2b trial, batefenterol produced statistical and clinically significant differences compared to placebo and numerically greater improvements in the primary end point of trough FEV1 compared to salmeterol after 4 weeks of dosing in patients with moderate to severe chronic obstructive pulmonary disease (COPD).
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INTRODUCTION Chronic obstructive pulmonary disease (COPD) is now recognized as a global health problem and is projected to be the third leading cause of death worldwide by 2020. The pulmonary component of this debilitating disease is characterized by persistent and progressive airflow limitation. A combination of small airways disease (obstructive bronchiolitis) and parenchymal destruction (emphysema) are responsible for the airflow limitation component of COPD, with relative contributions varying across the patient population.1 Bronchodilators are recommended at all stages of COPD, with muscarinic acetylcholine receptor antagonists (MAs) and β2 adrenergic receptor agonists (BAs) being the most frequently used. For more advanced stages of the disease, long acting (LA) bronchodilators such as tiotropium (LAMA) and indacaterol © XXXX American Chemical Society
(LABA) are more desirable because of their 24 h duration of action controlling disease symptoms and improved patient compliance owing to their once-daily dosing regimen (Chart 1).2 Binary combinations of these agents, such as QVA149 (glycopyrronium plus indacaterol)3 and ANORO (umeclidinium bromide and vilanterol),4 show even greater improvements in lung function, while “triple therapy”, through the addition of an inhaled corticosteroid (ICS), is recommended in COPD patients at high risk for exacerbations. Historically inhaler devices have been limited to binary combinations though several companies are now applying their specific technologies to enable the formulation of three components.5 Received: December 10, 2014
A
DOI: 10.1021/jm501915g J. Med. Chem. XXXX, XXX, XXX−XXX
Drug Annotation
Journal of Medicinal Chemistry
simultaneously and achieve the appropriate balance of activities.9 In our first reported MABA drug discovery efforts, we identified an optimal linker length of nine atoms between the amine atoms of the biphenyl carbamate muscarinic and carbostyril pharmacophores, culminating in the early lead compound 1 (THRX-198321) (Chart 2).10 Further elaboration of this nonylalkyl chain to introduce additional functionalities such as secondary and tertiary amides, carbo- and heterocycles, while maintaining the overall nine atom linker length, proved to be well tolerated in vitro and in vivo.11 While a napadisylate crystalline form12 of 1 was identified, all attempts to crystallize the amide-linked MABAs 2 (THRX-109156) and 3 (THRX494732) (Chart 2) failed despite their promising biological profiles. In contrast, arylamide linked MABAs 4 and 5 (Chart 3) showed promising crystalline properties but lacked 24 h duration of action as β2 agonists in vivo. Using these compounds as a foundation for achieving suitable crystalline forms, in this article we describe the optimization of their biological properties toward the discovery of the clinical candidate 12f (TD-5959).
Chart 1. Once-Daily Long-Acting Bronchodilator Reference Standards
However, the regulatory path forward becomes even more complex with three, rather than two, agents. One possible solution is to combine two of the pharmacologies in a single molecule. Preclinical data support the hypothesis that muscarinic (M2, M3) and β2 receptors in the lung act through complementary pathways6 such that the resulting MABA would offer a desirable solution to achieving “triple therapy” in a single device, concomitantly matching the pharmacokinetics and pharmacodynamics of two of the three components. This project presented two significant drug discovery challenges: (1) designing compounds suitable for inhaled delivery with low systemic exposures; (2) designing dual pharmacology compounds such that both mechanisms of action demonstrate matched duration of action in vivo. To ensure minimal systemic exposure, an inhaled drug requires a low dose and poor oral bioavailability, since up to 90% of the dose may be swallowed.7 Antedrug approaches, such that the drug is rapidly metabolized upon reaching the bloodstream, further control for low systemic exposures.8 Current inhalation devices require highly crystalline material, and therefore, early screening for suitable crystalline forms in the discovery effort is critical. Dual pharmacology molecules are attractive because of the prospect of greater efficacy over single pharmacology agents and simplified pharmacokinetics over fixed dose combinations, but the challenges in early drug discovery are much greater because of the need to optimize both pharmacologies
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CHEMISTRY The synthetic route for compounds 4 and 12a−j (Scheme 1) began with the 1,4-addition of our biphenyl carbamate muscarinic orthostere 7, formed in one step from commercially available starting materials, to the appropriately aryl-substituted acrylamide 6. Lithium borohydride mediated reduction of the aryl ester afforded the alcohol, which was then subsequently oxidized to the aldehyde 10. Reductive amination with protected carbostyrilamine orthostere 1113 and subsequent removal of the silyl protecting group gave the MABA compounds 4, 12a−j. Reverse amides 5 and 19a−c were synthesized from amine building blocks 13 and 16 (Scheme 2). Primary amine 13 was prepared by alkylation of 7 with BOC-protected aminoethyl bromide, followed by BOC removal under standard conditions. Secondary amine 16 was accessed from amino alcohol 14, after Cbz protection and subsequent oxidation; this material was further used in a reductive amination with 7, and after hydrogenation of the Cbz group, 16 was isolated. Amines 13 and 16 were then individually coupled with commercially
Chart 2. Previously Described Theravance MABAs
B
DOI: 10.1021/jm501915g J. Med. Chem. XXXX, XXX, XXX−XXX
Drug Annotation
Journal of Medicinal Chemistry Chart 3. Unsubstituted Arylamide Linked MABAs
Scheme 1. Synthesis of Compounds 4, 12a−ja
Reagents: (a) DIPEA, 0 °C, DCM, 67%; (b) (i) 70 °C, 12 h; (ii) 50 °C EtOH, 6 M HCl; (iii) NH4HCO2, Pd/C (10 wt %), 40 °C, 12 h, 100%; (c) 6, 50 °C, THF/MeOH (9:1), 70−80%; (d) LiBH4, 0 °C, THF/MeOH (9:1) 20−80%; (e) DMSO, DIPEA, Py·SO3, −20 to 0 °C, DCM; (f) (i) 11, Na(OAc)3BH, DCM/MeOH (1:1); (ii) Et3N·3HF, DCM, 25−40% over three steps.
a
available benzoic acid 17 and oxidized to give 18. The desired MABA compounds 5, 19a−c were isolated upon subjection of 18 to reductive amination with the carbostyrilamine 11 and silyl group removal. N-Methyl compounds 24a−c were accessed through two different pathways depending on the availability of the substituted aryl ring (Scheme 3). Commercially available anilines were methylated by way of formylation and then reduced to give methylanilines 21. The acrylamide was then formed to facilitate a 1,4-addition of 7 to give intermediate 22. Aryl iodide (path A) was converted to benzaldehyde 23 using a palladium-mediated reaction with acetic formic anhydride. Aryl esters (path B) were converted to aldehyde 23, as described previously, through reduction to the alcohol and then oxidation. Reductive amination and silyl group removal completed the syntheses of MABAs 24a−c.
The meta-substituted anilides 30a−c were prepared in four steps from commercially available amino esters 25. The esters were converted to the acrylamides 26 and used in a 1,4-addition with the muscarinic orthostere 7. The resulting esters 27 were reduced to the alcohol and nosylated to give intermediate 28. The nosylate activation of the alcohols was the most viable route for the synthesis of these compounds, since the corresponding aldehyde was unstable because of its propensity to polymerize. Alkylation of the benzyl protected carbostyril building block 2912 with 28 followed by benzyl and silyl protecting group removal gave the MABA compounds 30a−c (Scheme 4).
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RESULTS AND DISCUSSION In a study of physical properties of inhaled drugs, high molecular weight and high total polar surface area (tPSA) were C
DOI: 10.1021/jm501915g J. Med. Chem. XXXX, XXX, XXX−XXX
Drug Annotation
Journal of Medicinal Chemistry Scheme 2. General Syntheses of Compounds 5, 19a−ca
a Reagents: (a) (i) 2-tert-butoxycarbonylaminoethyl bromide, DIPEA, MeCN, 50 °C; (ii) TFA/DCM (1:3), 70% over two steps; (b) (i) benzyl chloroformate, aq Na2CO3, THF; (ii) DMSO, DIPEA, Py·SO3, −20 to 0 °C, DCM, 95% over two steps; (c) (i) 7, Na(OAc)3BH, MeOH; (ii) Pd/C (10 wt %), H2(g), MeOH, 44% over two steps; (d) (i) HATU, DIPEA, DMF; (ii) DMSO, DIPEA, Py·SO3, −20 to 0 °C, DCM, 50% over two steps; (e) (i) 11, Na(OAc)3BH, DCM/MeOH (1:1); (ii) Et3N·3HF, DCM, 6−20% over two steps.
Scheme 3. Synthesis of Compounds 24a−ca
a Reagents: (a) (i) HCO2H, Ac2O; (ii) BH3·Me2S, THF, 80−90%; (b) (i) acryloyl chloride, NaHCO3, DCM; (ii) 7, DCM/EtOH (1:1), 90−95%; (c) AcOCHO, Et3SiH, DIPEA, Pd2dba3, dppe, MeCN, 78%; (d) (i) LiAlH4, THF; (ii) DMSO, DIPEA, Py·SO3, −20 to 0 °C, DCM, 69−82%; (e) (i) 11, Na(OAc)3BH, MeOH/DCM (1:1); (ii) Et3N·3HF, DMF/DCM (1:9), 26−52% over two steps.
identified as the key drivers for achieving long acting lung retained compounds.14 More recently, increases in basicity have been proposed to extend pharmacokinetic duration and favor lung, rather than systemic, exposure.7 Long residence time on
the receptor is also a precedented design feature for achieving long duration of action, with tiotropium often believed to be the best example to date in the inhaled drug space.15 However, while some elegant postrationalization to understand the D
DOI: 10.1021/jm501915g J. Med. Chem. XXXX, XXX, XXX−XXX
Drug Annotation
Journal of Medicinal Chemistry Scheme 4. General Syntheses of Compounds 30a−ca
a Reagents: (a) acryloyl chloride, NaHCO3, DCM, 95%; (b) 7, DCM/iPrOH (1:1), 60 °C, 90%; (c) (i) LiAlH4, THF, 0 °C; (ii) DABCO, DCM, nosyl chloride; (d) (i) NaHCO3, MeCN, 43% over three steps; (ii) Pd(OH)2, H2(g), AcOH, MeOH; (iii) Et3N·3HF, DMF/DCM (1:9), 59% over two steps.
the behavior of established once-daily compounds such as tiotropium and indacaterol. The 2-substituted compounds 12a, 12b, and 12g improved BA activity in vivo relative to 4 but failed to meet our BA criterion at 24 h (Table 5). However, the 3-methoxy compounds 12d and 12f both displayed significant BA bronchoprotection and pleasingly also retained MA activity. Our model also enabled us to assess the two activities working in union as MABAs. Greater bronchoprotection was observed than either MA or BA alone, demonstrating the cooperation between the M3 and β2 pathways. A more limited investigation of aryl ring substitution effects, due to the availability of commercial starting materials, was performed on the reverse amide 5 (Table 2). In this case, reduction in M3 potency was observed for both 3-methoxy 19a and 2,5-dimethyl 19b derivatives. The unsubstituted N-methyl analog 19c recovered M3 potency; however, this compound failed to produce crystalline forms in our early screens. Our general methodology for screening for crystalline compounds is described in detail in the Supporting Information; however, this was usually conducted in three stages: broad counterion screening in different solvent systems using evaporative crystallizations, identification of optimal crystallization conditions (e.g., vapor diffusion, antisolvent additions), and finally scale up and characterization of promising salt forms. Over the course of the MABA program the selection of the initial screen’s counterions was adapted as we learned more about the general properties of these molecules. Methylation of a selection of anilides from Table 1 offered mixed effects on M3 and β2 activities in vitro (Table 3). While M3 potency increased for the 2-chloro, 5-methoxy derivative 24a, the 3-methoxy 24b and 2-methyl 24c compounds displayed weaker M3 activity and marked reductions in β2 activity. In vivo, 24a demonstrated 24 h duration of action as a MA at 30 μg/mL; however, the lack of crystalline forms halted any further characterization of this compound.
features contributing to long residence times may be possible, it still remains challenging to prospectively design for slow offrate kinetics.16 Additionally, tiotropium has recently been shown to have much shorter off-rate kinetics under physiological versus nonphysiological conditions (46 and 462 min, respectively) than previously reported, suggesting that the molecule’s physical properties play a significant role in its duration of action.17 Compounds 4 and 5 possessed good physical property starting points for designing compounds with long duration of action given their high molecular weight (676 Da) and tPSA (156 Å2). Given the proximity of the linker aryl group to the carbostyril β2 orthostere, we decided to investigate the effect of modulating the ring electronics on the BA in vivo properties. A survey of electron donating and withdrawing groups and combinations thereof revealed some interesting trends in vitro (Table 1). The addition of chlorine in both the 2- and 3positions (12a and 12c, respectively) retained potency at both targets, while the 2-methoxy compound 12b exhibited reduced M3 potency, compared to its 3-substituted counterpart 12d. In contrast methyl substitution at the 2-position 12g was preferred for high M3 potency. Given these small structural changes are somewhat distal to the biphenyl carbamate orthostere, it is quite remarkable what effects are bestowed on the M3 potency profiles, highlighting the contributions these linker moieties are making toward in vitro activity on both targets. Retaining the optimal 3-methoxy group and adding the chlorine or methyl groups to either ortho position (to the anilide) also gave compounds 12e, 12f, 12i, and 12j worthy of further evaluation. Compounds 12a, 12b, 12d, 12f, and 12g were progressed into our in vivo bronchoprotection model18 after showing early signs of crystallinity and offering a good representation of the substituents surveyed. Our criteria for this assay were to achieve 40% or greater bronchoprotection at 24 h on both MA and BA activities. From our earlier MABA work, this threshold was considered a robust, reproducible response and consistent with E
DOI: 10.1021/jm501915g J. Med. Chem. XXXX, XXX, XXX−XXX
Drug Annotation
Journal of Medicinal Chemistry Table 1. M3, β2 Potency, β1 Selectivity, tPSA, and MW for Compounds 12a−ja
M3 Ki was measured at a time point where equilibrium was reached (either 1 or 6 h; see Supporting Information). Log sel. β1/β2 EC50 is described in the Experimental Section. a
F
DOI: 10.1021/jm501915g J. Med. Chem. XXXX, XXX, XXX−XXX
Drug Annotation
Journal of Medicinal Chemistry Table 2. M3, β2 Potency, β1 Selectivity for Compounds 19a−c
Table 3. M3, β2 Potency, β1 Selectivity for Compounds 24a−c
30b and 30c. In vivo, robust MA, BA, and MABA efficacies were demonstrated at 24 h, warranting further characterization of this compound (Table 5). Having identified 12d, 12f, and 30a as early in vitro leads with 24 h MA and BA duration of action in vivo, we conducted further characterization to assess onset of bronchoprotection and lung selectivity. All of these compounds demonstrated fast onset of action with significant and maximal MA and BA
We also investigated meta-substituted anilides that retained the nine-atom linker length between the orthosteric nitrogen atoms (Table 4). This phenylethyl substituted β2 orthostere motif is present in marketed LABAs such as arformoterol19 and indacaterol. In contrast to the benzylamides described earlier (Tables 1−3), the most interesting compound from this small set was the unsubstituted 30a, which offered the best in vitro profile when compared to the methoxy-substituted compounds G
DOI: 10.1021/jm501915g J. Med. Chem. XXXX, XXX, XXX−XXX
Drug Annotation
Journal of Medicinal Chemistry Table 4. M3, β2 Potency, β1 Selectivity for Compounds 30a−c
Table 5. Guinea Pig Einthoven Model of Bronchoprotection Data at 24 h for Compounds 1, 4, 5, 12a, 12b, 12d, 12f, 12g, 30aa 24 h, % bronchoprotection MA compd
dose, μg/mL
tiotropium indacaterol 1 4 12a 12b 12d 12f 5 12g 30a
10 100 100 100 100 100 100 100 100 100 100
75 ± NA 72 ± 98 ± NT 22 ± 81 ± 48 ± 74 ± 92 ± 51 ±
BA n=6
7 6 0.3
n=6 n=5
16 3 9 3 3 14
n n n n n n
= = = = = =
NA 43 ± 3 10 ± 8 −2 ± 3 25 ± 13 33 ± 20 72 ± 4 47 ± 5 20 ± 1 20 ± 7 46 ± 6
3 6 8 3 6 5
MABA
n n n n n n n n n n
= = = = = = = = = =
NA NA
6 6 6 4 3 6 8 3 6 6
77 ± 4
n=8
96 ± 1 72 ± 4
n=6 n=6
a
The TFA salt form was dosed in all of the initial experiments. The edisylate salt form of 12f did not alter the efficacy or dose concentration delivered to the animals when compared with the TFA salt form.
Table 6. Guinea Pig Einthoven Model of Bronchoprotection and Pilocarpine Induced Salivation Data at 1.5 h for Compounds 1, 4, 12d, 12f, 30a 1.5 h, % bronchoprotection MA compd
dose, μg/mL
tiotropium indacaterol 1 4 12d 12f 30a
10 100 100 100 100 100 100
90 ± NA 94 ± NT 94 ± 75 ± 77 ±
2 1 1 5 6
BA n=6 n=6 n=6 n=8 n=6
NA 74 ± 63 ± 47 ± 70 ± 73 ± 80 ±
6 5 5 5 4 7
MABA
n n n n n n
= = = = = =
6 6 6 6 8 6
NA NA NT NT NT 92 ± 3 93 ± 2
1.5 h, % inh of pilocarpine
n=8 n=6
dose, μg/mL
% inh
100 NA
99 ± 0.3
n=6
NT 82 ± 5 −3 ± 12 4 ± 12 23 ± 5
n n n n
300 450 500 500
= = = =
6 6 5 6
evaluating the sialagogue response to pilocarpine in guinea pigs after pretreatment with various doses of the test compound.21 Dry mouth is the most common side effect of tiotropium.22 At 1.5 h postdose, 12d, 12f, and 30a all displayed significantly reduced effects when compared with tiotropium and the unsubstituted arylamide 4 in inhibiting sialagogue responses to pilocarpine. While a crystalline edisylate salt form of 12f had been discovered,23 no crystal forms of 12d or 30a had been
activities at the earliest time point measured (1.5 h) (Table 6). Interestingly, both compounds (1 and 4) that lacked BA duration at 24 h showed substantial BA bronchoprotection at this early time point. One explanation for this observation might be that tachyphylaxis is occurring via the β-arrestin pathway; however, the biased agonism nature of these molecules has not been characterized.20 The lung retention and selectivity of our MABA compounds were measured by H
DOI: 10.1021/jm501915g J. Med. Chem. XXXX, XXX, XXX−XXX
Drug Annotation
Journal of Medicinal Chemistry Table 7. In Vitro and in Vivo Pharmacokinetics for 12f in Rats in vitro data
iv
compd
CACO-2 Papp × 10−6 (cm/s)
HLM T1/2 (min)
rat in vivo PK, dose (mg/kg)
CL (L h−1 kg−1)
Vdss (L/kg)
T1/2 (h)
po, F (%)
12f
