# Clark Still

W. Clark Still is an American chemistry professor at Columbia University who co-founded [Pharmacopeia Inc.](https://www.edgepedia.org/pharmacopeia-inc), a combinatorial-chemistry drug-discovery company, in 1993.<sup>[1](https://www.bioworld.com/articles/490766)</sup> Pharmacopeia applied the encoded combinatorial library method developed in Still's Columbia laboratory to synthesize and screen very large collections of small molecules for pharmaceutical partners; it went public in December 1995, and its drug-discovery business was ultimately acquired by Ligand Pharmaceuticals in 2008.<sup>[2](https://www.sec.gov/Archives/edgar/data/1002388/000103605097001016/0001036050-97-001016.txt)</sup><sup> • </sup><sup>[3](https://www.genengnews.com/news/ligand-inks-stock-for-stock-purchase-deal-with-pharmacopeia-worth-55m/)</sup>

| Key fact | Detail |
|---|---|
| Founded | Pharmacopeia, Inc., incorporated March 1993<sup>[2](https://www.sec.gov/Archives/edgar/data/1002388/000103605097001016/0001036050-97-001016.txt)</sup> |
| Scientific founders | W. Clark Still (Columbia University) and Michael Wigler (Cold Spring Harbor Laboratory), with Paul Bartlett, Bertram Rowland, and Lawrence Bock<sup>[1](https://www.bioworld.com/articles/490766)</sup> |
| Initial financing | $7 million from Avalon Ventures, Institutional Venture Partners, and Kleiner Perkins Caufield & Byers (1993)<sup>[1](https://www.bioworld.com/articles/490766)</sup> |
| IPO | December 5, 1995; 2,990,000 shares at $16 per share<sup>[2](https://www.sec.gov/Archives/edgar/data/1002388/000103605097001016/0001036050-97-001016.txt)</sup> |
| Core technology | ECLiPS, encoded combinatorial libraries on polymeric support, licensed from Columbia and Cold Spring Harbor<sup>[4](https://www.sec.gov/Archives/edgar/data/1002388/000110465903005131/j8559_10k.htm)</sup> |
| Peak scale | More than seven million compounds synthesized; 687 employees at end of 2002<sup>[4](https://www.sec.gov/Archives/edgar/data/1002388/000110465903005131/j8559_10k.htm)</sup> |
| Outcome | Stock fell from about $5 to $1.19 in 2008; acquired by Ligand at a 52% premium in stock<sup>[3](https://www.genengnews.com/news/ligand-inks-stock-for-stock-purchase-deal-with-pharmacopeia-worth-55m/)</sup> |

## Scientific work behind the company

Still's research at Columbia on sequence-selective peptide binding by synthetic receptors using encoded combinatorial libraries, published in *Accounts of Chemical Research* in September 1995, described the encoded-library approach that underpinned Pharmacopeia's platform.<sup>[5](https://doi.org/10.1021/ar950166i)</sup> The American Chemical Society's author profile lists Still with an h-index of 65 and 29,654 citations as corresponding author of that paper, a measure of how widely the work was read.<sup>[5](https://doi.org/10.1021/ar950166i)</sup>

He was also a named inventor on the underlying patents. US patent 7067326 B2, filed January 13, 1995, names W. Clark Still, Ge Li, and [Helma Wennemers](https://www.edgepedia.org/helma-wennemers) as inventors and was assigned to Columbia University and later to Pharmacopeia LLC.<sup>[6](https://www.google.com.pg/patents/US7067326)</sup> The exclusive license of this tagging technology from Columbia University and [Cold Spring Harbor Laboratory](https://www.edgepedia.org/cold-spring-harbor-laboratory) became the intellectual property core of the company.<sup>[4](https://www.sec.gov/Archives/edgar/data/1002388/000110465903005131/j8559_10k.htm)</sup>

## Founding Pharmacopeia Inc.

Pharmacopeia, Inc. was incorporated in March 1993 to conduct drug-discovery research and produce chemical libraries for collaborations and for its own use.<sup>[2](https://www.sec.gov/Archives/edgar/data/1002388/000103605097001016/0001036050-97-001016.txt)</sup> Its screening technology was developed by Still at Columbia and [Michael Wigler](https://www.edgepedia.org/michael-wigler) at Cold Spring Harbor Laboratory, who were the company's scientific founders; Paul Bartlett of UC Berkeley and Bertram Rowland were also founders, and [Avalon Ventures](https://www.edgepedia.org/avalon-ventures) general partner Lawrence Bock was a founder as well.<sup>[1](https://www.bioworld.com/articles/490766)</sup>

**Early funding** came quickly: in November 1993 the company announced $7 million in venture financing from Avalon Ventures, Institutional Venture Partners, and Kleiner Perkins Caufield & Byers, on top of roughly half a million dollars in seed financing from Avalon.<sup>[1](https://www.bioworld.com/articles/490766)</sup> From inception through September 30, 1997, Pharmacopeia received $101.9 million in net equity financing proceeds and $49.4 million in collaborative research, license fee, and milestone payments, with an accumulated deficit of $33.3 million and working capital of $51.3 million at that date.<sup>[2](https://www.sec.gov/Archives/edgar/data/1002388/000103605097001016/0001036050-97-001016.txt)</sup>

## Technology and business model

ECLiPS, or Encoded Combinatorial Libraries on Polymeric Support, synthesized compounds on tiny plastic beads carrying proprietary chemical tags that identified any compound active in a biological screening assay. Using a "Direct Divide" method, a library of 10,000 to 500,000 or more small-molecule compounds could be built with only 50 to 200 individual chemical reactions.<sup>[4](https://www.sec.gov/Archives/edgar/data/1002388/000110465903005131/j8559_10k.htm)</sup> At its launch the company reported it could create a library of more than 100,000 compounds attached to beads, and claimed its scientists could prepare pools of tens of millions of compounds and screen them within days.<sup>[1](https://www.bioworld.com/articles/490766)</sup>

The company made money through collaborative drug-discovery deals with pharmaceutical partners. Its sixth such collaboration, with Akzo Nobel/NV Organon, was worth $19 million in equity investments, license fees, and R&D funding, with potentially tens of millions more in milestone payments plus royalties; by that point collaborations with Daiichi, Bayer, Schering-Plough, Berlex, and Sandoz carried about $58 million in committed license-fee and R&D funding, $37 million in equity investments, and potential target milestones of another $88 million.<sup>[7](https://www.bioworld.com/articles/486676)</sup> Pharmacopeia also operated a software segment, Accelrys Inc., alongside its Drug Discovery segment.<sup>[4](https://www.sec.gov/Archives/edgar/data/1002388/000110465903005131/j8559_10k.htm)</sup>

## IPO, growth and scale

Pharmacopeia's IPO offering date was December 5, 1995, with 2,990,000 common shares registered and Alex. Brown & Sons, Cowen & Company, and UBS Securities as underwriters.<sup>[2](https://www.sec.gov/Archives/edgar/data/1002388/000103605097001016/0001036050-97-001016.txt)</sup> The stock priced at $16 per share and closed at $23.25 on its first trading day.<sup>[7](https://www.bioworld.com/articles/486676)</sup> Net offering proceeds of $43.757 million were allocated to laboratory expansion ($10.622 million), library creation, and screening ($17.055 million), debt repayment ($1.139 million), and working capital ($14.941 million).<sup>[2](https://www.sec.gov/Archives/edgar/data/1002388/000103605097001016/0001036050-97-001016.txt)</sup>

By the end of 2002, Pharmacopeia Drug Discovery's scientists had synthesized more than seven million diverse small molecules with drug-like characteristics using ECLiPS.<sup>[4](https://www.sec.gov/Archives/edgar/data/1002388/000110465903005131/j8559_10k.htm)</sup> That year PDD performed discovery work for customers including Schering-Plough, Novartis, AstraZeneca, and Takeda, with one customer accounting for roughly 50% of PDD's revenue and 12% of consolidated revenue.<sup>[4](https://www.sec.gov/Archives/edgar/data/1002388/000110465903005131/j8559_10k.htm)</sup> The company had 687 regular employees at December 31, 2002, including 263 chemists, biologists, and engineers holding doctorates.<sup>[4](https://www.sec.gov/Archives/edgar/data/1002388/000110465903005131/j8559_10k.htm)</sup>

## By the numbers

- $7 million initial venture round, 1993, plus about $0.5 million seed from Avalon<sup>[1](https://www.bioworld.com/articles/490766)</sup>
- IPO, December 5, 1995: 2,990,000 shares at $16; first-day close $23.25<sup>[2](https://www.sec.gov/Archives/edgar/data/1002388/000103605097001016/0001036050-97-001016.txt)</sup><sup> • </sup><sup>[7](https://www.bioworld.com/articles/486676)</sup>
- Cumulative funding to September 30, 1997: $101.9 million equity proceeds plus $49.4 million collaboration payments<sup>[2](https://www.sec.gov/Archives/edgar/data/1002388/000103605097001016/0001036050-97-001016.txt)</sup>
- More than seven million compounds synthesized by end of 2002<sup>[4](https://www.sec.gov/Archives/edgar/data/1002388/000110465903005131/j8559_10k.htm)</sup>
- 687 employees, including 263 doctorate holders, at December 31, 2002<sup>[4](https://www.sec.gov/Archives/edgar/data/1002388/000110465903005131/j8559_10k.htm)</sup>
- 2008 share price slide: about $5 in early 2008 to a $1.19 close before Ligand's offer<sup>[3](https://www.genengnews.com/news/ligand-inks-stock-for-stock-purchase-deal-with-pharmacopeia-worth-55m/)</sup>

## Restructuring, sale to Ligand and aftermath

Pharmacopeia, headquartered in [Princeton, New Jersey](https://www.edgepedia.org/princeton-new-jersey) and incorporated in Delaware, operated its Drug Discovery business as a division from its 1993 inception; a 2003 [Form 10-K](https://www.edgepedia.org/form-10-k) states the segment's assets, operations, and business were spun into a new wholly owned subsidiary, Pharmacopeia Drug Discovery, Inc. (PDD), while the same filing elsewhere references the transfer occurring in May 2002.<sup>[4](https://www.sec.gov/Archives/edgar/data/1002388/000110465903005131/j8559_10k.htm)</sup>

In 2008 the company restructured, cutting 15% of its workforce in May and a further 40% in August; its shares, trading around $5 at the start of the year, closed at $1.19 before Ligand Pharmaceuticals announced a stock-for-stock acquisition representing a 52% premium, and Pharmacopeia stock rose to $1.47 in early trading on the announcement.<sup>[3](https://www.genengnews.com/news/ligand-inks-stock-for-stock-purchase-deal-with-pharmacopeia-worth-55m/)</sup> The patent record shows the corporate end of the line: on July 7, 2009 an assignment recorded the merger of Pharmacopeia, Inc., via Latour Acquisition, LLC, into Pharmacopeia LLC, which became assignee of the Still patents.<sup>[6](https://www.google.com.pg/patents/US7067326)</sup>

## References

1. BioWorld: Pharmacopeia garners $7M in initial financing (November 29, 1993). https://www.bioworld.com/articles/490766
2. Pharmacopeia, Inc. SEC filing (1997). https://www.sec.gov/Archives/edgar/data/1002388/000103605097001016/0001036050-97-001016.txt
3. GEN: Ligand Inks Stock-for-Stock Purchase Deal with Pharmacopeia Worth $55M. https://www.genengnews.com/news/ligand-inks-stock-for-stock-purchase-deal-with-pharmacopeia-worth-55m/
4. Pharmacopeia, Inc. Form 10-K (2003). https://www.sec.gov/Archives/edgar/data/1002388/000110465903005131/j8559_10k.htm
5. Discovery of Sequence-Selective Peptide Binding by Synthetic Receptors Using Encoded Combinatorial Libraries, Accounts of Chemical Research. https://doi.org/10.1021/ar950166i
6. US7067326B2, Synthetic receptors, libraries and uses thereof, Google Patents. https://www.google.com.pg/patents/US7067326
7. BioWorld: Pharmacopeia–Organon collaboration. https://www.bioworld.com/articles/486676

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*Topic: Encyclopedia › Society and history › Economics and business › Founders, operators, and investors › Life-science and healthcare founders and companies › Biotechnology and therapeutics › Scientific and physician founders*

*Initially written Sep 19, 2026 · Reviewed: Sep 19, 2026; Sep 30, 2026 · Edited: Sep 30, 2026 · Last review: Sep 30, 2026*

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