Anaptysbio fails to excite ahead of pivotal push


Anaptysbio’s attempts to recover from the painful failure of its eczema candidate etokimab have taken a knock: the biggest trial conducted so far on its next pipeline hope, imsidolimab, has bombed. The anti-IL-36R project was tested in 59 patients with moderate to severe palmoplantar pustulosis (PPP), but the company could only muster various numerical improvements over placebo; on the primary endpoint the study was a clear bust. PPP is a non-fatal form of pustular psoriasis that, like other manifestations of the disease, is thought to be driven by IL-36 signalling. Generalised pustular psoriasis (GPP) is the big prize here, a setting in which Anaptysbio is pushing into phase III on the back of data in eight patients. The competitor to watch is Boehringer Ingelheim, which claimed a win in GPP with a similarly targeted MAb, spesolimab, a couple of years ago. The private group has also run trials in PPP but has been cagey about results, suggesting a benefit here is harder to tease out. Still, Anaptysbio investors were clearly hoping for stronger signals from imsidolimab in PPP before the push into pivotal trials; shares in the biotech plunged 39% in early trade.

Topline Ph2 Poplar data with imsidolimab/ANB019
LSMD PPPASI Relative to baseline Imsidolimab Placebo Difference p-value
Week 4 -3.1 -3.1 0.0 0.99
Week 8 -4.6 -3.7 -0.9 0.62
Week 12 -5.6 -3.4 -2.2 0.25
Week 16 (primary endpoint) -6.1 -6.3 0.2 0.93
LSMD; least-squares mean difference, PPPASI = palmoplantar pustular psoriasis area severity index. Source: press release.

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