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Crop Protection Discovery – Is Being the First Best? Thomas C. Sparks, James E Hunter, Beth A. Lorsbach, Greg Hanger, Roger Gast, Greg Kemmitt, and Robert J Bryant J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.8b03484 • Publication Date (Web): 11 Sep 2018 Downloaded from http://pubs.acs.org on September 13, 2018
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Journal of Agricultural and Food Chemistry
For: Journal of Agricultural and Food Chemistry Review
Crop Protection Discovery – Is Being the First Best? Thomas C. Sparks*, James E. Hunter, Beth A. Lorsbach, Greg Hanger, Roger E. Gast, Greg Kemmitt, Robert J. Bryant** Corteva Agrisciences™, Agriculture Division of DowDuPont™, Dow AgroSciences. Discovery Research 9330 Zionsville Road, Indianapolis, IN 46268 **Agranova, Orpington, Kent BR6 9AP UK
*Corresponding Author: Ph: 317-337-3064 Fax 317-337-3205 E-mail:
[email protected] ACS Paragon Plus Environment
Journal of Agricultural and Food Chemistry
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ABSTRACT
2
Current crop protection chemicals span an array of chemistry classes and modes of
3
action.
4
active ingredients competing with each other for market position. In this competition,
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the first product to market in a new class or mode of action may or may not have an
6
advantage depending on a number of parameters including relative efficacy against the
7
target pests, pest resistance, regulatory pressures, synthetic complexity, and marketing
8
effectiveness.
9
protection compounds has been declining, and patenting strategies have gotten more
10
sophisticated, making it more challenging to break into an existing area of chemistry.
11
One result is new classes of chemistry tend to be smaller, making first to market more
12
beneficial than in the past.
13
chemistry has the opportunity to set positioning and expectations.
14 15 16 17
Keywords Agrochemical discovery, Crop protection compounds, Pesticide
18 19 20 21 22 23 24 25 26 27
Typically, within each chemistry class there are multiple chemically distinct
The number of companies involved in the discovery of new crop
Additionally, the first into a market with a new class of
Abbreviations used ALS - acetolactate synthase inhibitor DMI – demethylase Inhibitor EPSPS - enolpyruvyl-3-shikimate phosphate synthase FRAC – Fungicide Resistance Action Committee GM – genetically modified HRAC –Herbicide Resistance Action Committee IRAC – Insecticide Resistance Action Committee MoA - mode of action SDHI - succinate dehydrogenase inhibitors
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INTRODUCTION
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The increasing global population1 requires expanded production of food to feed the
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additional two billion people expected on this planet by 2050.
32
pathogens and weeds that negatively impact crop productivity remains an ongoing,
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essential component to successful and economical food production. However, pest and
34
pathogen resistance to existing commercial pesticides continues to expand3,4 and
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escalating regulatory and environmental requirements4,5 limit the utility of many
36
established classes of chemistry. Thus, there remains a need for new and novel crop
37
protection products creating opportunities for innovation to address grower and
38
consumer needs.
Controlling insects,
39 40
Although there has been substantial consolidation in the crop protection agrochemical
41
industry, especially among companies involved in the basic research and development
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of new crop protection products,4,5 new active ingredients
43
and developed (Figure 1)6 representing a range of classes. A long standing and central
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approach in crop protection discovery programs is the utilization of competitor patents
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as a source of inspiration for new agrochemcials as well as the further evolution of a
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chemical class by the originating company seeking to expand the spectrum and
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utility.4,7,8 This enduring approach in discovery programs9 has led to a long line of crop
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protection active ingredients belonging to common chemical families and manifesting
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their bioactivity via the same mode of action.
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introduction of the once revolutionary organophosphate insecticide, parathion, in the
continue to be discovered
For example, the discovery and
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1940’s, lead to a diverse range of organophosphate insecticides10 over the next 70
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years with an excess of 150 different active ingrediants.11 Similar, but less extreme
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examples exist for a range of existing chemical classes of insecticides (N-methyl
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carbamates, cyclodienes, pyrethroids, neonicotinoids), fungicides (triazoles, strobilurins)
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and herbicides (aryloxyphenoxys, sulfonyl ureas / sulfonamides).
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the first molecule that becomes a product in a particular agrochemical class remained
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the primary molecule in that class and market in spite of numerous other chemically
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analogous products being introduced.
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neonicotinoid developed and has maintained its sales lead for more than 20 years, in
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spite of the introduction of several other neonicotinoids (Table 1).
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leading product of some classes emerged only after the first molecule was introduced.
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This was the case for the α-cyano-pyrethroids, cypermethrin and deltamethrin, which
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quickly displaced permethrin,12 one of the very first photostable pyrethroids
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commercialized.
In some instances
Imidacloprid, for example, was the first
Conversely, the
65 66
Slightly more than half of global pesticide sales are derived from active ingredients
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introduced since 1991, about evenly divided between fungicides, herbicides and
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insecticides (Figure 2), clearly demonstrating the value of newer products in the
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marketplace.
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chemicals, with some highs and lows, over the past 25 years (Figure 1). As such, this
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analysis will focus on the metrics for active ingredients launched post-1990 since data is
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more readily available and the aim is to better understand the newer areas of chemistry,
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and hence more recent driving forces in the current marketplace. From this data an
Since 1991, there has been a continuous flow of new crop protection
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effort is made to identify attributes that allow for the continued success of some first to
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market crop protection products, as well as the attributes that become opportunities for
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follow-on crop protection compounds to build on and surpass their forerunner(s) in
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terms of sales. In the second part of this perspective a number of case studies are
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presented which illustrate the relative importance of the factors in governing how the
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first to market may fare, and how important those attributes may be in determining new
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modes of action (MoAs) offering success in future years.
81 82
DATA
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In an attempt to identify the most important and relevant factors that make a compound
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a sales leader within a class of chemistry, data from selected classes of the nearly 300
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herbicidal, fungicidal and insecticidal active ingredients registered in the last 25 years
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was used in the analysis.
87
defined by the Fungicide Resistance Action Committee (FRAC),13 Herbicide Resistance
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Action Committee (HRAC), 14 and the Insecticide Resistance Action Committee (IRAC).
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15
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sales / volume data.16 Since many of the active ingredients launched in the last 25 years
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are still new to the market and have not yet seen significant sales, active ingredients
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included in the analysis had to have 2016 sales of at least $50 million, and have at least
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one member of the class had to have sales of >$100 million for that class to be
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included.
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greater than $50 million in sales, only the top in sales are recorded in Table 1. Lastly,
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compounds belonging to any of the unknown MoA classes, or those with a multisite
Crop protection chemical classes were based on those
The data for the analysis was derived, in part, from launch date and 2016 end-user
If more than five a.is within a class were launched since 1991 and had
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designation were omitted. Some classes were included wherein the first member was
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launched prior to 1991.
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classes / subclasses, with nine of the ten first to market herbicides falling into this
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category. In these cases, the data for the first to launch agrochemical was added back
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to the analysis. Any pre-1991 launched product which was a sales or volume leader
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was added back. Finally, an approximate product launch order is provided in Table 1.
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Pre-1991 compounds within the class as well as those with sales less than $50 million
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were considered when assigning a launch order to a product. No attempt was made to
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distinguish the product launched within the same calendar year and they are treated as
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being introduced into the marketplace concurrently. The resulting 27 crop protection
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chemical classes used for the analysis (Table 1) represent a useful sampling of the
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defined crop protection compound classes, accounting for just under half ($30.2 billion;
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47.8%) of the $63.3 billion 2016 end-user value of the crop protection chemical market.
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Table 1 also includes eight of the top ten products by sales. Most notably missing is the
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number one crop protection product in terms of both sales and volume, glyphosate,
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since it was launched in 1974 and has not had any follow-up analogs that have become
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products. Finally, in addition to data from Agranova,16 for some specific analyses, an
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internal proprietary database was used representing Manufacturer Level Sales
115
providing a fair representation of overall market value for the most widely used actives
116
and products.
117
ANALYSIS.
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Each product area was evaluated, and in doing so it is important to note that there are
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some distinct market differences between herbicides, fungicides and insecticides that
This situation was especially prevalent among herbicide
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influence the value and success of an active ingredient. First, the global herbicide
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market in 2016, at ~$27 billion was roughly 50% larger than either the global fungicide
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(~$18 billion) or insecticide markets (~$16 billion) (Figure 3). Secondly, the herbicide
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and fungicide markets, more so than the current insecticide market, are dependent on
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mixtures of active ingredients, primarily to gain the necessary spectrum to address the
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weed or pathogen complexes in many crop systems.
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product is sold containing a single active ingredient it is often formulated so that the
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grower can easily tank mix it with other pesticidal products. The commercial objective is
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to give the grower a convenient single solution that provides the spectrum of control
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they require. This means that the breadth of spectrum and efficacy of a single herbicide
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or fungicide active ingredient is important, but also how its strengths and weaknesses
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complement the strength and weaknesses of another herbicide and / or fungicide
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selected for tank mixing or developed as a pre-mixture. It is increasingly important to
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understand that the relative efficacy of an herbicide or a fungicide may shift with time
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due to resistance development, which presents opportunities for development of new
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active ingredients and / or mixing partners.
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herbicide area where the cornerstone of a market segment may be the control of a
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single or a few key weed species within a geography, that are no long effectively
138
controlled by existing active ingredients
139
Also impacting crop protection chemistry use patterns are the changing farm practices
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that have evolved over the last 25 years that have affected the herbicide, fungicide and
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insecticide markets unequally. Specifically, genetically modified (GM) crops been most
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impactful in the herbicide market and least impactful on the fungicide business. Recent
If an herbicidal or fungicidal
This has been especially true in the
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studies suggest GM insect resistant crops have reduced the amount of insecticides
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used on cotton and maize,17,18 impacting the value of these markets for insecticides. In
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contrast, GM crops with herbicide tolerance simply resulted in a significant shift in the
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types of herbicides applied.
147
fungicides and insecticides in the seed treatment market.19 The attributes required for a
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successful foliar and seed applied pesticide are not identical, but can at times be met by
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a single active ingredient, as in the case of the insecticide imidacloprid.20 The flexibility
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to use imidacloprid in both market segments contributes to its continued success
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relative to other neonicotinoids.
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One commonality among all three markets is that the agronomic and environmental
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attributes (i.e. soil and water residual, non-target toxicity, bioaccumulation, etc.) of an
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active ingredient do not solely determine its commercial success. The global reach of
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the offering company; registration; marketing; and sales strategies and well as out
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licensing agreements can all impact the trajectory of an active ingredient’s adoption by
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growers. Although important, due to their complexity, and company specific nature,
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these factors (sales, marketing, etc.) are beyond the scope of the present analysis.
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However, regardless of business strategy and its execution, crop protection active
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ingredients which best meet the grower’s and increasingly consumer / societal needs,
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are most likely to have the largest impact in the market.
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HERBICIDES.
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Within the three acetolactate synthase (ALS) inhibitor subclasses (HRAC B1, B2 and
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B3) (Table 1) and the seven other herbicidal MoAs examined, no first to market product
Somewhat tied to GM crops is the growing use of
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currently leads in sales or volume. Three factors have played a role in this. First, the
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nine MoAs in this analysis cover selective herbicides.
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controls unwanted plants, but is safe to the traditionally bred crops. Most often this is
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accomplished by taking advantage of differential metabolism of the active ingredient.21
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Secondly, the coupling of non-selective herbicides, primarily glyphosate and glufosinate,
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with GM row crops expressing resistance to these two herbicides, greatly altered
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herbicide use patterns in the associated crops supplanting a number of selective
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herbicides, and also affecting interest in the discovery and development of new
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herbicides.21
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impacted equally. Those selective herbicides developed for weed control within corn,
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cotton or soybean, in regions accepting GM organisms, like the Americas, were
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impacted to a larger extent than those targeting non-GM crops like rice or wheat.
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However, the recent appearance of weed resistance to a number of herbicides,
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especially glyphosate, has re-kindled interest in new herbicide discovery. Although no
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new herbicidal MoA has been brought to the market in over 25 years,22,23 researchers
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have looked for and found innovative solutions through new active ingredients that act
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within established MoA classes, providing improved attributes over existing options to
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meet growers continually evolving needs. These products were not just targeted for
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non-GM market segments. A newer best-in-class product may exhibit improved efficacy
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or broader spectrum of weed control which could include controlling undesired
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broadleaves or grasses that have developed resistance to other herbicides,24,25
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including the previously mentioned non-selective herbicides. Technology which offers
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the grower increased flexibility is also rewarded in this space.
That is, the active ingredient
Furthermore, not all selective herbicides within a MoA class were
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That could include
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improved selectivity to a single crop, expanding selectivity to cover multiple crops, or a
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shorter soil half-life in the environment that may positively affect crop rotation flexibility
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allowing growers greater leeway to adjust planting decisions based on factors such as
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commodity crop prices.
192
FUNGICIDES.
193
Unlike herbicides, there has been substantial innovation within the fungicide space in
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bringing new MoAs to the marketplace, and GM fungicide resistant crops have not yet
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been a disruptive technology. Of the eight FRAC target site groups shown in Table 1,
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all active ingredients within five of the MoA classes were launched within the last 25
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years. Within the three groups in which the first to market active ingredient was
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launched pre-1990, none remain as sales leaders, including metalaxyl.
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the factors making sales leaders of particular follow-on herbicides, superior efficacy and
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environmental fate attributes26,27 of the follower, mefenoxam, drove its success. It is a
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somewhat unique example though, in that mefenoxam [R methyl-N-2-(methoxyacetyl)-
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N-(2.6-xylyl)-alanate)] is simply the bioactive (R)-isomer of metalaxyl. In addition to the
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active ingredient within mefenoxam, half of the material within metalaxyl is its
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stereochemical isomer with the S-configuration, which is ~1000 times less potent.27
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Interestingly, the innovation in this instance is really the heterogeneous chemical
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catalysis process that allowed for the multi-ton preparation of the key chiral
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intermediate, methyl R N-(2,6-dimethylphenylalanate), on route to mefonaxam.28
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The evolution of succinate dehydrogenase inhibitors (SDHI) is also illustrative of factors
209
influencing the success of a.is within a class over time. Carboxin the first commercial
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Analogous to
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SDHI was launched primarily as a seed treatment in 1966. The utility of the SDHI MoA
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against additional fungal market segments was demonstrated with thifluzamide (Rohm
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& Haas, 1997), which could be applied foliarly as well as via seed treatment, and then
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followed by boscalid (BASF, 2003) which offered additional spectrum. Changing pest
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pressure has also impacted this chemical class. Since 2000, Asian soybean rust, which
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many SDHI fungicides perform well against, has become a major problem with >US$ 2
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billion being spent annually in Brazil alone on chemical control of this pathogen.29
217
Almost 50 years after the launch of a product in this FRAC group, agrochemical
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discovery groups continue to mine this well-established MoA area as shown by the
219
recent registration submissions for impyrfluxam.30
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Within the MoA classes where the first to market active ingredient was launched within
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the last 25 years, three of the five offerings remain market sales and volume leaders.
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Two offerings, ametoctradin and fludioxonil, FRAC categories C8 and E2 respectively,
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represent molecules used in products leading to significant market value, but without
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apparent competitive fast-follow molecules.
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competitors were not using these early entries as templates for follow-on innovation, but
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the lack of new innovation around these particular fungicide classes may be due to a
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number of factors that coalesced to limit a.is that act via these MoAs and possess
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properties that would allow them to be commercially competitive in more economically
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valuable fungicide market segments. This has not been the case within the chemistries
230
that act at the mitochondrial electron transport complex III Q0 site as shown by the
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research / patent activity in the late 1980s and 1990s.31,32 A number of major
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agrochemical companies of the time (Zeneca Agrochemicals,33 BASF,34 Novartis35 and
This should not be interpreted that
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DuPont36) saw the value proposition around the mitochondrial electron transport
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complex III Q0 site inhibitors and their research resulted in four products being launched
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in quick succession in 1998 and 1999. Azoxystrobin (Zeneca), launched in 1998 clearly
236
differentiated from kresoxim-methyl in terms of pathogen spectrum and global crop
237
utility, which is reflected in its current (2016) higher standing in sales (Table 1).
238 239
INSECTICIDES.
240
In this arena the crop protection industry has been the most prolific in bringing new
241
MoAs to the market place. Of the two subgroups and seven other major insecticidal
242
MoA groupings in this analysis (Table 1), products in all but two were launched after
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1991. Also striking is the number of first to market active ingredients which remain a
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market leader. Abamectin launched before 1991, as well as six of the seven first to
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market MoA products launched post-1990, have held on to their number one sales and
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volume leadership, four of these are doing so even 20 years after launch. Like the
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fungicide azoxystrobin, excellent spectrum and global crop utility is key to keeping them
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best-in-class. In addition two of the insecticides, spinosad and abamectin, are unique
249
among all market leaders in that these two are complex natural products produced via
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fermentation rather than chemical synthesis. Many of the technologies, capabilities and
251
infrastructure to discover and bring to market fermentation derived products differ from
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those required for traditional synthetic crop protection products.
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AgroSciences further capitalized on those competitive advantages by developing semi-
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synthetic derivatives, emamectin benzoate37 and spinetoram,38 respectively, which
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provided an altered or enhanced spectrum coupled with improved efficacy.
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Merck and Dow
Both of
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these active ingredients became successful insecticides, but in 2016 had not yet
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eclipsed their natural product predecessors (Table 1).
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insecticides fewer followers within a class is observed, relative to what is observed
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among herbicides and to a lesser extent fungicides.
260
competition within the molecules of a MoA class, which contributes to some extent to
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the number of first to market active ingredients that remain leaders within their grouping.
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There may be a number of reasons for fewer follow-on chemistries among insecticides.
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First, of the seven MoA groupings comprised of synthetically manufactured active
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ingredients, all members within six of the groupings were launched less than 25 year
265
ago, thus the time window for research organizations to discover and develop follow-on
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chemistry within many of the insecticidal MoA classes has been shorter when compared
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to the more mature herbicide and fungicide MoA classes. Second, the fact that there are
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fewer discovery organizations to follow-on due to industry consolidation over this same
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time period has likely played a role as well.4,5 Also, in the case of the two insecticidal
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voltage dependent sodium channel blockers indoxacarb (IRAC Group 22A)38 and
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metaflumizone (IRAC Group 22B),40 there are no class followers despite being an active
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area of research by a number of companies.41,42 In this space, environmental fate
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issues as well as identifying blockers with high insect efficacy and an acceptable
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therapeutic index vs. homologous target site of non-target animal species was a
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challenge.41
276 277
SELECTED CASE STUDIES
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Even among synthetic
Fewer followers mean less
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The following case studies were selected to highlight the factors which enabled the first
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to market within a chemical class / MoA group to remain the economic winner
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(glyphosate and spinosad) or makes it vulnerable to being supplanted by a follow-on
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offering (demethylase Inhibitor (DMI) class of fungicides and cyclic ketoenols).
282 283
Glyphosate (HRAC G). Glyphosate, launched as the first commercial herbicidal 5-
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enolpyruvyl-3-shikimate phosphate synthase (EPSPS) inhibitor remains the market
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leader within its MoA class after 45 years. Based solely on this active ingredient
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effectiveness at controlling a broad spectrum of perennial weeds and favorable
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environmental profile vs. many other hericides,43 one might expect some difficulty in
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dethroning it as the market leader within the EPSPS class.
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EPSPS class, discounting the trimesium salt of glyphosate, is no other HRAC-
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recognized EPSPS herbicide has been launched within this time span. That after all
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these years no other commercially efficacious active ingredient in this space has been
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launched speaks to the very narrow structure activity requirements about the EPSPS
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target site.
294
Glyphosate, in the context of coupling an herbicidal MoA with a transgenic herbicide
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resistant crop was actually a fast follower behind bromoxynil resistant cotton and
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glufosinate resistant canola.44
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introduced in 1996. By 2015 half the acreage of genetically modified crops contained a
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glyphosate resistance trait, and over half the volume of glyphosate used that year was
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applied to those crops.23 The previously mentioned spectrum of glyphosate, favorable
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environmental properties, plus technological advancements that allowed for improved
What is unique about the
Glyphosate resistant canola and soybean were
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crop tolerance traits to be incorporated in elite row crop lines without yield drag23,44
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propelled and kept glyphosate as the leader in this segment. In the upcoming years
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glyphosate, in relation to its use against genetically modified crops, may come under
304
pressure from other non-selective herbicides as weed resistance to glyphosate grows
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and new herbicidal resistant traits (2,4-D, etc.) come on line.
306
C-14 Demethylase Inhibitor Fungicides (FRAC G1). The clearest example of a first to
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launch fungicide being surpassed by later entrants in the same MoA is shown by the
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Demethylase Inhibitor (DMI) class of fungicides.
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with an initial focus on cucurbits, fruits and ornamentals in 1969.
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pyrimidine-carbinol DMI fungicide followed in 197545 with registrations in tree fruits and
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vines.
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innovations by a number research companies. The result, a succession of 25 triazole
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DMI fungicides having been launched since 1976,46 producing over this period of time a
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series of new fungicidal DMI market leaders, starting with triadimefon and progressing
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from propiconazole, to tebuconazole and prothioconazole.46
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chemistry were explored, newer molecules brought forward properties that not only
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broadened the spectrum of pathogens controlled, but also increased the overall crop
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utility and thus sales. No database captures the total breadth of crops in which DMI’s
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are used, however, one would just need to look at a label for triforine compared to
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tebuconazole to see the incredible expansion in utility that has occurred with continued
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innovation. Clearly, the earliest DMI patents opened the door for decades of innovation
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that continues today with recent announcements from BASF for mefentrifluconazole
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(trade name Revysol™)47 which is reported to be more intrinsically active at the target
Triforine was the first registered DMI Fenarimol, a
Initial triazole discoveries by Janssen Pharmaceuticals led to a series of
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As new avenues of
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site than other azoles and effective against many resistant pathogen strains48 that have
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eroded the overall effectiveness of the DMI fungicides through the years. Over the last
326
decade the environmental impact versus economic importance of many members of this
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class have been a contentious issue, especially in Europe.49
328
opportunity may exist for yet a new DMI market leader with attributes that are more
329
closely aligned with the economic and environmental goals of the stakeholders in this
330
debate.
331
Spinosyns (IRAC Group 5). The spinosyns are fermentation derived natural products
332
(NP) discovered through a NP screening program in the mid-1980s.50,51 Launched in
333
1997, spinosad is a naturally occurring mixture of two of the most insecticidal spinosyns,
334
spinosyns, A and D.51 Spinosad acts at an allosteric site on the α6 subunit of the insect
335
nicotinic acetylcholine receptor,52 the first class of insecticidal chemistry to exhibit this
336
MoA.
337
because of its effectiveness in controlling a range of chewing insect pests, novel MoA
338
and very favorable environmental and toxicological profile.51
339
spinosyn-based product was launched, spinetoram, a semi-synthetic derivative with an
340
improved spectrum and efficacy.52 Spinetoram is the result of an extensive structure
341
activity exploration, ultimately successfully driven by an artificial intelligence-based
342
quantitative structure activity approach.38 Thus far, spinosad has retained its market
343
leadership in this small class of insecticides, primarily due to the complexities
344
associated with a challenging fermentation process and associated strain improvement.
345
However, it is anticipated that in the near future spinetoram could become the market
346
leader in this novel class of insecticides. While other spinosyn derivatives have been
Going forward, the
Spinosad is widely used in organic as well as conventional farming in part
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In 2007 a second
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investigated,53 to date only spinosad and spinetoram have been commercialized.
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Although there have been a number of published synthetic approaches to the spinosyn
349
core,54 the excessive number of chemical and / or enzymatic steps (29–44) involved
350
makes synthetic production of the spinosyn macrolide an unattractive route to support
351
even a limited SAR program, let alone serving as a basis for a production route.
352
Hence, thus far, production of the spinosyns has remained through fermentation.
353
However, two decades after the launch of spinosad, the successful de novo design of
354
synthetic spinosyn mimics has been reported wherein the spinosyn macrolide core has
355
been replaced by a simple triaryl ring system; the first time that a synthetic mimic of a
356
macrolide NP has been successfully simplified in either crop protection of
357
pharmaceuticals.55
358
class of insecticides.
359
Cyclic Ketoenols. The cyclic ketoenols are a novel group of tetronic and tetramic acid
360
derivatives effective on a range of mite and sap-feeding insects currently composed of
361
spirodiclofen,
362
development). The first compound in this class, spirodiclofen, appeared in the ISO
363
common names listing in 200056 and was registered in 2002. Spirodiclofen came out of
364
a research program on herbicidal protoporphyrinogen-IX-oxidase inhibitors that
365
morphed into a series of herbicidal acetyl CoA carboxylase inhibitors, which in turn
366
further morphed into the tetronic acids which were then found to exhibit miticidal
367
activity.57 Further exploration of this area of chemistry then lead to spiromesifen, a new
368
analog with good activity on whiteflies (i.e. Bemisa tabaci), as well as mites,58 launched
369
a year after spirodiclofen in 2003.
Thus the possibility exists for new future additions to the spinosyn
spiromesifen,
spirotetramat
and
most
recently
spiropidion
(in
A third molecule in this series (spirotetramat) that
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has become the class market leader, resulted from a parallel discovery effort around
371
tetramic acids,58 exhibiting a broad spectrum of activity against sap-feeding insects and
372
both phloem and xylem mobility.57,58 Launched in 2008, spirotetramat has had a far
373
larger impact on the market (based on sales) than the other members of this class
374
(Table 1) with sales (2016 end user, USD) of $326 million versus $181 million and $81
375
million for spiromesifen and spirodiclofen, respectively. In this case the broad spectrum
376
sap-feeding insect activity has been an important factor in the greater use of
377
spirotetramat, especially as a control option for sap-feeding insects resistant to
378
mainstream insecticides such as the neonicotinoids. Other new potential products in
379
this class of insecticides are being investigated by other companies (i.e. spiropidion56 by
380
Syngenta).
381
382
FUTURE PROSPECTS FOR FIRST TO MARKET PESTICIDES
383
As outlined above, there are a number of parameters that can and have impacted
384
whether the first active ingredient in a new class remains the market leader or is
385
supplanted by a later follow-on compound. The relative importance of these parameters
386
will vary based on the nature of the active ingredient, its target therapeutic area,
387
intended crop(s) and company goals / emphasis. These factors can include;
388
1 – Resistance or shifting pest spectrum in the market place.
389
2 – Regulatory or other significant advantage: i.e. new MoA, improved environmental or
390 391
toxicological profile. 3 – Improved efficacy
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4 – New technology to allow exploitation: i.e. coupling with transgenic plants, new delivery options or other tools. 5 - Speed of follow-up: i.e. fast follow (within a year or two) vs. slow follow (5 to 10 years after initial product).
396
6 – Barriers to entry: such as complex chemistry or fermentation
397
7 – Improvements in synthetic routes or synthetic building blocks allowing new options.
398
8 – Marketing effectiveness of a company.
399 400
These parameters, and likely others, can have an effect singly, or in many instances it is
401
a combination of several of these factors that leads to market significance.
402 403
The consolidation that has occurred in the agrochemical side of the crop protection
404
industry has resulted in fewer, but far larger companies,5 that are capable of funding the
405
increasing costs of discovery, development and registration of new crop protection
406
chemicals.5,7 One potential consequence is that the number of competing active
407
ingredients in a new class of chemistry is likely to be smaller than in the past11 due to
408
fewer different companies exploring a particular area. As such, the first compound in a
409
new class may have an advantage if it provides a suitable combination of efficacy,
410
spectrum, affordability and favorable regulatory / environmental profile. Since any new
411
product is by necessity an attempt to balance these parameters, the relative success at
412
addressing all of these components will influence the relative ease or difficultly for
413
competing active ingredients to make inroads.
414
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415
In reviewing the data in Table 1, it is notable that the majority of the companies listed
416
are US and European, and few from Asia (e.g. Japan). In part this is an artifact of
417
selection criteria used, coupled with listing only the top five molecules in a class. As
418
noted earlier, many crop protection classes are rather large, especially those that have
419
been around for some time including a number of herbicides: sulfonylureas (39),
420
triazines (34), auxins (25+);59 fungicides: strobilurins (20), SDHIs (21), triazoles (31);59
421
and insecticides: carbamates (42), pyrethroids (80), organophosphates (165).11
422
many instances Japanese companies have also developed products for these and other
423
classes; however, due to the their smaller corporate size and the rising cost of
424
development, especially for global registrations, some of these companies need to co-
425
develop or license out their discoveries,5 thus losing some of the benefits of being first
426
to market.
In
427 428
As noted above, only one class of herbicides that fit our analysis parameters, was
429
developed since 1991 (triazolopyrimidines, ALS inhibitors) and the first product in that
430
class has been eclipsed by a number of more recently developed analogs (Table 1). All
431
other herbicides belong to classes which had their origins prior to 1991, and in all cases
432
the first compound in that class is now far exceeded in terms of sales by more recent
433
class members. The situation is similar for fungicides, with the exception of the largest
434
class of fungicides, the strobilurins, wherein the first member of the class, azoxystrobin,
435
has remained the market leader (Table 1).
436
resistance was slower to emerge as a problem, especially when compared to the
437
insecticides.3,5
For both herbicides and fungicides,
However, the increasing rise of both herbicide and fungicide
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438
resistance,3,60 will likely alter the current landscape making any new fungicide with a
439
new MoA, or especially a new herbicide with a new MoA, a difficult molecule to easily
440
displace.
441
Also as noted above, it is only in the insecticide arena that most first to market
442
molecules developed since 1991 have retained their market leading positions (Table 1).
443
It is also among the insecticides where several new classes with new MoAs have been
444
developed since 1991.11 In part this state of affairs is in response to a combination of
445
expanding insecticide resistance,3,5 desire for more environmentally favorable
446
compounds5,11 coupled with the need to find suitable replacements for many members
447
of older classes of chemistry.
448
that the size of new and future classes of chemistry are likely to remain small, with only
449
a few members. Thus, for insecticides there appears to be a greater likelihood for the
450
first molecule in a class to remain the prevailing product for some period of time.
451
Thus as outlined above, perhaps now more than in the past, the prospects for the first
452
molecule in any one of the therapeutic areas is likely to have a significant advantage.
453
Although the first into a new area of chemistry has to work out all of the issues for that
454
chemistry, potentially forging a path for others to follow, that company also captures an
455
initial patent estate for that chemistry. Patents from each company have gotten larger,
456
more numerous, and more complex, making it that much more challenging to break into
457
an area of chemistry, although it is obviously occurring. That is why, in many instances,
458
the time investment in discovering a new area of chemistry is no greater than trying to
459
break into an existing area of chemistry.4
460
market space and gets to set the stage for grower use, perception and consumer
As noted previously,11 it is also within the insecticides
Additionally, first to market captures the
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461
acceptance. Conversely, next generation molecules can potentially be positioned to
462
address gaps in spectrum, show efficacy increases and provide additional convenience
463
for the grower, all assuming that the first molecule leaves such gaps open.
464
ACKNOWLEDGEMENTS
465
The authors thank Drs. Jeffrey Nelson and Michael Loso for useful discussions and
466
comments during the preparation of this article.
467
reviewers and especially the Editor for their very useful suggestions.
We also thank the anonymous
468
469
The authors declare no competing financial interest.
470
Author Contributions: BAL & TCS defined the project, JEH & TCS with assistance from
471
RJB, GH, GK & REG conducted the data analysis; all authors contributed to organizing,
472
writing and editing the manuscript.
473
474
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Figure Legends
650
Figure 1. Product areas of new active ingredients launched since 1991. Data derived
651
from launch dates.16
652 653
Figure 2. Global value of new active ingredients launched before and after 1991, and
654
among fungicide, herbicides and insecticides launched since 1991. Data derived from
655
2016 end user sales.16
656 657
Figure 3. Distribution of the global crop protection chemicals market – 2016 end user
658
sales.16
659 660
Figure 4. Total modes of action as defined by FRAC13, HRAC14 and IRAC.15 Excludes
661
unknown, multisite inhibitors or target site subgroups.
662
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Figure 1.
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Figure 2.
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Figure 3.
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Figure 4.
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Table 1. Year of Launch and End User Sales for Selected HRAC, FRAC and IRAC Mode of Action Groups
Herbicides HRAC
B1
B2
B3
C1
E
F2
Class / Compound
Company
Launch Year & 1 (Discovery Company)
2
Launch 3 Order
Acetyl CoA carboxylase inhibitors diclofop-methyl 4 fenoxaprop-P-ethyl* clodinafop-propargyl haloxyfop-P-methyl cyhalofop-butyl 5 pinoxaden
Bayer CropScience Bayer CropScience Syngenta Dow AgroSciences Dow AgroSciences Syngenta
1975 (Hoeschst) 1990 (Hoeschst) 1995 (Ciba-Geigy) 1995 (Dow) 1996 (Dow) 2006 (Syngenta)
54 326 345 103 114 369
1 9 12 12 14 17
Sulfonylureas chlorsulfuron primisulfuron-methyl nicosulfuron* iodosulfuron-methyl sodium mesosulfuron-methyl trifloxysulfuron-sodium
Du Pont Syngenta Ishihara Sangyo Kaisha Bayer CropScience Bayer CropScience Syngenta
1982 (DuPont) 1991 (Ciba-Geigy) 6 1992 (ISK) 1999 (AgrEvo) 2001 (AgrEvo) 2001 (Ciba-Geigy)
28 116 373 214 419 151
1 9 12 26 27 27
Imidazolinones imazapyr imazethapyr* imazapic imazamox
BASF BASF BASF BASF
1985 (AmCy) 1989 (AmCy) 1996 (AmCy) 1997 (AmCy)
90 250 56 163
1 4 5 6
Triazolopyrimides flumetsulam diclosulam florasulam penoxsulam pyroxsulam thiencarbazone-methyl
Dow AgroSciences Dow AgroSciences Dow AgroSciences Dow AgroSciences Dow AgroSciences Bayer CropScience
1994 (Dow) 1998 (Dow) 1999 (Dow) 8 2004 (DAS) 2008 (DAS) 2008 (DAS)
55 167 236 276 220 209
1 7 9 13 14 14
Triazines simazine atrazine* amicarbazone
Syngenta Syngenta Arysta LifeScience
1955 (Geigy) 1957 (Geigy) 2004 (Bayer)
47 210 64
1 2 17
PPO inhibitors oxadiazon flumioxazin sulfentrazone carfentrazone-ethyl* saflufenacil pyraclonil
Bayer CropScience Sumitomo Chemical FMC FMC BASF Bayer CropScience
1969 (AgrEvo) 1992 (Sumitomo) 1996 (FMC) 1997 (FMC) 2009 (BASF) 2009 (AgrEvo)
87 239 325 291 271 96
1 8 11 13 20 20
Triketones pyrazoxyfen isoxaflutole mesotrione* topramezone tembotrione pyrasulfotole
Ishihara Sangyo Kaisha Bayer CropScience Syngenta BASF Bayer CropScience Bayer CropScience
1986 (ISK) 1998 (Rhône-Poulenc) 2001 (Syngenta) 2006 (BASF) 2007 (Bayer) 2008 (Bayer)
7 239 865 166 246 180
1 5 6 8 9 10
7
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Journal of Agricultural and Food Chemistry
K3
L
O
Benzamides propachlor acetochlor* metazachlor S-metolachlor flufenacet dimethenamid-P
Monsanto Monsanto BASF Syngenta Bayer CropScience BASF
1965 (Monsanto) 1991 (Monsanto) 1993 (BASF) 1997 (Ciba-Geigy) 1998 (Bayer) 2000 (Sandoz)
7 494 146 530 144 271
1 11 12 16 17 18
CBI inhibitors dichlobenil quinclorac* indaziflam
Generic BASF Bayer CropScience
1960 (Philips-Duphar) 1991 (BASF) 2010 (Bayer)
4 55 133
1 3 4
Auxins MCPA 2,4-D* aminopyralid
Generic Generic Dow AgroSciences
1940s (multiple) 9 1940s (multiple) 2006 (DowElanco)
91 569 192
1 4 23
9
Fungicides FRAC
C2
C3
C8
D1
E2
G1
Class / Compound
Company
Launch Year (Discovery company)
Sales
Launch order
Phenylamides metalaxyl* mefenoxam
Syngenta Syngenta
1983 (Ciba-Geigy) 1996 (Ciba-Geigy)
162 240
1 5
SDHIs carboxin boscalid* penthiopyrad isopyrazam bixafen fluxapyroxad
Chemtura (Crompton) BASF Mitsui Chemicals Agro Syngenta Bayer CropScience BASF
1966 (Uniroyal) 2003 (BASF) 2008 (Mitsui) 2010 (Syngenta) 2011 (Bayer) 2011 (BASF)
70 433 134 280 280 154
1 7 8 9 10 10
Strobilurins azoxystrobin* kresoxim-methyl trifloxystrobin pyraclostrobin picoxystrobin fluoxastrobin
Syngenta BASF Bayer CropScience BASF Syngenta Bayer CropScience
1998 (Zeneca) 1998 (BASF) 1999 (Novartis) 2001 (BASF) 2001 (Zeneca) 2005 (Bayer)
1,758 276 1,110 1,402 169 405
1 1 4 7 7 11
Triazolopyrimidyl amines ametoctradin*
BASF
2010 (BASF)
101
1
Anilinopyrimidines pyrimethanil* cyprodinil
BASF Syngenta
1994 (Schering) 1995 (Ciba-Geigy)
60 173
1 2
Phenylpyrroles fludioxonil*
Syngenta
1995 (Ciba-Geigy)
190
1
C14-Demethylase inhibitors triforine prochloraz* difenoconazole
BASF BASF Syngenta
1969 (Celamerck) 1983 (Boots) 1991 (Ciba-Geigy)
2 95 395
1 5 18
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tetraconazole epoxiconazole prothioconazole
Isagro-Ricerca BASF Bayer CropScience
1993 (Agrimont) 1995 (BASF) 2004 (Bayer)
104 443 729
20 27 33
Carboxylic acid amides dimethomorph* iprovalicarb mandipropamid
BASF Bayer CropScience Syngenta
1994 (Celamerck) 1998 (Bayer) 2008 (Syngenta)
142 53 238
1 2 5
Company
Launch Year (Discovery company)
Insecticides IRAC
Class / Compound
2B
Phenylpyrazoles
fipronil* ethiprole 4A
05
06
22A 22B 23
28
1
Sales
Launch order
BASF
1994 (Rhône-Poulenc)
616
1
Bayer CropScience
2005 (Rhône Poulenc)
66
2
Neonicotinoids imidacloprid* acetamiprid thiamethoxam thiacloprid clothianidin dinotefuran
Bayer CropScience Nippon Soda Syngenta Bayer CropScience Sumitomo Chemical Mitsui Chemicals Agro
1994 (Nihon Bayer) 1996 (Nippon Soda) 1997 (Syngenta) 2000 (Nihon Bayer) 2002 (Takada) 2002 (Mitsui)
1,322 377 1,302 165 565 105
1 2 4 5 6 6
Spinosyns spinosad* spinetoram
Dow AgroSciences Dow AgroSciences
1997 (Elanco) 2008 (DAS)
293 125
1 2
AvermectinsMilbemycins abamectin* milbemectin emamectin benzoate
Syngenta Mitsui Chemicals Agro Syngenta
1988 (Merck) 1992 (Sankyo Agro) 1998 (Merck)
1,040 74 185
1 2 3
Oxadiazines Indoxacarb*
DuPont
1998 (DuPont)
212
1
Semicarbazones metaflumizone*
BASF
2007 (Nihon Nohyaku)
111
1
Ketoenols spirodiclofen spiromesifen spirotetramat*
Bayer CropScience Bayer CropScience Bayer CropScience
2002 (Bayer) 2003 (Bayer) 2008 (Bayer)
81 181 326
1 2 3
Diamides flubendiamide chlorantraniliprole* cyantranilaprole
Nihon Nohyaku / Bayer Du Pont Du Pont
2007 (Nihon Nohyaku) 2007 (DuPont) 2012 (DuPont)
392 1,235 62
1 1 3
16
61
Data adapted in part from Agranova and The Pesticide Manual 16 Millions USD, data from Agranova 3 The estimated order in which a compound was launched relative to the first compound listed 4 * = volume leader 5 Bold = sales leader 6 Ishihara Sangyo Kaisha 2
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Journal of Agricultural and Food Chemistry
7
American Cyanamid Dow AgroSciences 9 62 Discovered simultaneously and independently by several different groups / companies 8
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Graphical Abstract
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