Shares of AnaptysBio are down more than 16% after imsidolimab failed to meet the endpoint in a Phase II trial assessing its efficacy in hidradenitis suppurativa.
Shares of AnaptysBio are down more than 16% after it announced its Phase II trial assessing imsidolimab for the treatment of moderate-to-severe hidradenitis suppurativa (HS) failed to meet primary and secondary endpoints.
Imsidolimab, an anti-IL-36 receptor, did not demonstrate improvement over placebo in the Phase II HARP study. As a result, AnaptysBio will discontinue clinical development of imsidolimab in HS, a chronic skin condition that causes small, painful lumps to form under the skin.
The trial included 149 patients diagnosed with moderate to severe HS. The patients all had at least 5 inflammatory nodule and abscess (AN) lesion counts, less than 20 draining fistulas and were at least at Hurley stage 2, the company noted.
The primary endpoint was the mean change in AN lesion count from baseline after 16 weeks of treatment. A secondary endpoint, the Hidradenitis Suppurativa Clinical Response (HiSCR) measure, was used to measure improvement in HS.
Despite missing endpoints, imsidolimab was safe and tolerable, the company stated.
Paul Lizzul, chief medical officer of AnaptysBio, called the results of the Phase II study “disappointing.”
While the company has canceled the clinical development of imsidolimab as a potential treatment for HS, it remains focused on ongoing studies in generalized pustular psoriasis. Imsidolimab is currently being assessed in the GALLOP Phase II study for this indication, for which it earned Orphan Drug designation from the FDA in 2020.
A life-threatening illness, generalized pustular psoriasis is associated with uncontrolled IL-36R signaling. Enrollment in the Phase III GEMINI-1 GPP is ongoing and topline data is expected in the fourth quarter of 2023.
Daniel Faga, who took over as interim president and CEO of AnaptysBio in March, said the company remains optimistic about imsidolimab for generalized pustular psoriasis. However, given the company’s ongoing strategic portfolio review, it has decided to out-license imsidolimab prior to potential FDA approval, Faga said.
Now, R&D efforts will focus on AnaptysBio’s novel immune cell modulator pipeline, including its two checkpoint agonists in clinical-stage development, rosnilimab and ANB032. Rosnilimab, a PD-1 agonist antibody, is being assessed in the AZURE Phase II study for moderate-to-severe alopecia areata. Data from that study are expected in the first quarter of 2023, the company announced.
Additionally, AnaptysBio expects to file an Investigational New Drug application for an initial Phase II trial assessing ANB032, a BTLA agonist antibody, in the fourth quarter of this year.
With $570 million in available cash, Faga said AnaptysBio is well-financed to support the development of these two assets.
“We believe their mechanisms of action, acting directly on cell types mediating disease pathology, have the potential to treat a broad range of autoimmune and inflammatory disorders,” he said in a statement.
