Verastem approval proves toxic


Verastem followed yesterday’s US approval of Copiktra (duvelisib) with a China licensing deal, but the company needs to deliver more than regional partners to build confidence in its product. Shares in the biotech slumped 20% yesterday in the wake of the FDA’s green light; “sell the news” was probably partly to blame, though a lengthy black box on the drug’s prescribing label, warning of several significant toxicities, also unsettled investors. The warnings are largely in line with another PI3K inhibitor, Zydelig from Gilead. The sellside jumped to Verastem’s defense and claimed that on measures such as hepatotoxicity Copiktra could actually have an advantage. But it is incontrovertible that both of these drugs are highly toxic, and will surely remain last resort options – a fact that has caused expectations for Zydelig to be substantially reined in over the last couple of years. Analysts covering Verastem expect Copiktra to overtake Zydelig by 2024, according to EvaluatePharma’s consensus, a view that seems highly optimistic given the relative sizes of their owners. Perhaps this was the reality that dawned on investors yesterday.

Outlook for marketed PI3K inhibitors
    Annual sales ($m)
Product Company 2018e 2020e 2022e 2024e
Aliqopa (copanlisib)* Bayer 67 211 382 572
Zydelig (idelalisib) Gilead Sciences 152 170 205 241
Copiktra (duvelisib) Verastem 1 91 225 326
Source: EvaluatePharma. *Aliqopa label does not have any black box warnings.

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