Pharma BD Deal Intelligence

Pfizer Inc. / Arena Pharmaceuticals

2021 · Acquisition/Merger · $6.7B · Complete

Pfizer's $6.7B cash acquisition of Arena Pharmaceuticals paid off on thesis: etrasimod won FDA approval as VELSIPITY for ulcerative colitis in October 2023, with EU approval following in 2024. Pfizer has since pruned the broader program, dropping Phase 2 atopic dermatitis and alopecia areata studies in May 2024 to narrow focus onto the approved GI indication.

CALLED IT — OFF BY 20
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The coverage arc

Jul 15, 2002 Wikipedia Neutral

Pfizer acquired Arena Pharmaceuticals for $6.7B.

Mar 14, 2022 Pfizer concludes Arena Pharmaceuticals acquisition for $6.7bn - Pharmaceutical Technology Bullish

Pfizer completed its $6.7 billion acquisition of Arena Pharmaceuticals, gaining etrasimod, an oral selective S1P receptor modulator in development for…

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Pfizer acquired Arena Pharmaceuticals for $6.7 billion in cash ($100.00/share) via a tender offer plus second-step merger, announced December 13, 2021 and completed March 11, 2022. The strategic rationale was Arena's immuno-inflammatory pipeline, led by etrasimod, an oral, once-daily, selective sphingosine-1-phosphate (S1P) receptor modulator. Etrasimod won U.S. FDA approval as VELSIPITY for moderately-to-severely active ulcerative colitis on October 12, 2023, followed by EU approval in 2024 — validating the deal's core thesis. Pfizer subsequently pruned the broader etrasimod program, discontinuing Phase 2 studies in atopic dermatitis and alopecia areata in May 2024 as part of a cost-and-pipeline review, narrowing the asset toward its approved UC indication and adjacent GI development.

Key facts

Disease & market context

Ulcerative Colitis

900K US cases/yr · $12.0B Global UC Market (2024)

Disease Overview

Ulcerative colitis is a chronic inflammatory bowel disease affecting the colon. The treatment landscape includes aminosalicylates, steroids, biologics (anti-TNF, anti-integrin, anti-IL-12/23), JAK inhibitors, and S1P modulators. Velsipity offers oral once-daily convenience as the second S1P modulator approved for UC.

S1P Modulator Class

Velsipity (etrasimod) FDA-approved October 2023. Phase 3 showed 27-32% remission vs 7% placebo. Competes with Zeposia (ozanimod) from BMS as well as JAK inhibitors Xeljanz and Rinvoq. Oral convenience differentiates from injectable biologics like Entyvio and Stelara.

Deal timeline

Related deals — scored

DealYearValueOutcome
Pfizer Inc. / Arena Pharmaceuticals (this deal)2021$6.7B63
Pfizer Inc. / BioNTech SE2020$748M100
Pfizer Inc. / FoldRx Pharmaceuticals201099
Pfizer Inc. / Medivation Inc.2016$14.0B86
Pfizer Inc. / Wyeth2009$68.0B86
Pfizer Inc. / Warner-Lambert Company2000$90.0B83
Pfizer Inc. / Arvinas, Inc.2021$2.4B77

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