A year after Abcuro raised $200 million to fund a phase 2/3 muscle disease trial of its anti-KLRG1 antibody, the study has flunked all its main goals.
The Massachusetts-based biotech was evaluating the antibody, called ulviprubart, in a phase 2/3 trial of 272 patients with inclusion body myositis (IBM), a muscle-wasting disease that affects about 50,000 people across the U.S. and Europe. Abcuro had a lot riding on the study, with plans to file an approval application with the FDA if the study were a success.
Unfortunately for Abcuro, things haven’t gone to plan. The study missed its primary endpoint of a statistically significant change in IBM Functional Rating Scale (IBMFRS) total score at Week 76 compared to placebo. The secondary endpoints didn’t offer any more comfort, with the trial missing key tests of muscle and hand grip strength.
Grasping for a silver lining, Abcuro pointed to a prespecified subgroup analysis of patients with mild to moderate disease who showed an improvement in their IBMFRS score and in secondary endpoints. These “suggest the potential of ulviprubart’s disease-modifying activity in such patients,” the biotech said in its Feb. 24 release.
“While we are disappointed that the Muscle trial did not reach statistical significance in the overall study population, we are encouraged by the clear and meaningful magnitude of improvements observed in patients with mild to moderate disease, as well as its favorable safety and tolerability profile overall,” Abcuro Chief Medical Officer H. Jeffrey Wilkins, M.D., said in the release.
Abcuro is targeting KLRG1 to drive the depletion of cytotoxic T cells in autoimmune diseases. While other players in the space are targeting CD25, CD2, CD52 and ICOS with the same goal in mind, Abcuro has been betting on KLRG1 because expression is restricted to highly cytotoxic late-differentiated effector memory and effector T cells.
The idea is that ulviprubart will deplete cells that drive autoimmune disease without affecting regulatory T cells and central memory T cells.
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Abcuro isn’t ready to give up on ulviprubart yet, with Wilkins adding in this morning’s release that the company plans to discuss a path forward with the FDA.
“This is the first study to investigate this mechanism of action in IBM, and we believe further study of ulviprubart in patients with less severe disease is an important next step towards being able to provide an effective treatment option for patients with IBM,” the CMO said.
Still, the big-name backers that took part in Abcuro’s $200 million series B round last year—including Sanofi Ventures, RA Capital and Bain Capital Life Sciences—may be disappointed with what they got for their money.
