Pharma BD Deal Intelligence
A $150M oncology bet that became a near-total write-off within one quarter. Biogen expensed $123.1M of the purchase price immediately after closing its Conforma acquisition, and both Hsp90 inhibitor assets—CNF1010 and CNF2024/BIIB021—were discontinued as Biogen abandoned oncology altogether.
A $150M oncology bet that turned into a near-total write-off within one quarter, and both lead assets were dead within a few years as Biogen abandoned oncology altogether
Full analysis, sources & comparables →The deal — $150M closing plus $100M in milestones — gives Biogen Idec an oncology platform around HSP90 antagonists and integrates Conforma's 40 employees into…
Conforma's VP of corporate development said the $250M buyout grew out of strategic partnership discussions rather than financing necessity — Conforma was…
Despite roughly two decades of clinical development across multiple sponsors, no HSP90 inhibitor has achieved FDA approval, with hepatic and ocular toxicities…
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Oncology HSP90 inhibitors; $150M upfront + up to $100M milestones
A $150M oncology bet that turned into a near-total write-off within one quarter, and both lead assets were dead within a few years as Biogen abandoned oncology altogether
Assessment window: 15yr post-close.
HSP90 is a molecular chaperone that stabilizes a wide range of oncoproteins (HER2, BRAF, EGFR, BCR-ABL, AKT). Inhibiting HSP90 should trigger client-protein degradation across multiple tumor types simultaneously — an attractive theory that has repeatedly failed to translate into a marketed drug due to liver and ocular toxicity and modest single-agent activity.
At deal time (May 2006), the HSP90 inhibitor field was crowded: Kosan Biosciences had tanespimycin (17-AAG, KOS-953); Infinity Pharmaceuticals had IPI-504 (retaspimycin); Synta had ganetespib; and Pfizer/Serenex had SNX-2112. Conforma's CNF1010 (a 17-AAG analog) and oral CNF2024 (BIIB021) sat alongside these in early clinical development. The deal aimed to extend Biogen Idec's oncology footprint beyond Rituxan/lymphoma into solid tumors at the company's San Diego oncology center of excellence. The HSP90 class as a whole subsequently disappointed: Kosan's tanespimycin program was discontinued by Bristol-Myers Squibb after the 2008 Kosan acquisition; Synta's GALAXY-2 trial of ganetespib failed in NSCLC in 2014; and as of 2026 no HSP90 inhibitor has been approved. Biogen Idec ultimately deprioritized small-molecule oncology, and the $100M milestone tier was never paid out.
| Deal | Year | Value | Outcome |
|---|---|---|---|
| Biogen Idec Inc. / Conforma Therapeutics Corporation (this deal) | 2006 | $250M | 11 |
| Biogen Idec Inc. / Elan Corporation plc (Tysabri rights) | 2013 | $3.2B | 77 |
| Eli Lilly and Company / ICOS Corporation | 2006 | $2.3B | 87 |
| Crucell N.V. / Berna Biotech AG | 2006 | $450M | 85 |
| Lonza Group AG / Cambrex Bioproducts and Biopharma businesses | 2006 | $460M | 83 |
| Reckitt Benckiser plc / Boots Healthcare International | 2006 | $3.4B | 82 |
| Genentech, Inc. (Roche Group) / Tanox Inc. | 2006 | $919M | 80 |
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