Incyte’s first bid to build a better Jakafi regimen has ended in failure. A phase 3 trial of parsaclisib and Jakafi has come screeching to a halt ahead of schedule after an independent data monitoring committee found it was on course to miss its primary endpoint.
The LIMBER-304 study tested the effect of parsaclisib in people with the bone marrow cancer myelofibrosis. Incyte’s Jakafi is already used to treat the condition, but in two phase 3 monotherapy trials it failed (PDF) to trigger a 35% or greater fall in spleen volume in 35% and 59% of patients. The search for options for non-responders to Jakafi led Incyte to combine its approved drug with the investigational parsaclisib.
Adding the PI3Kδ inhibitor to Jakafi failed to have the desired effect. At a preplanned interim analysis, the independent data monitoring committee found the study is unlikely to meet its primary endpoint and recommended stopping the trial early. The recommendation is not because of safety. Incyte is now working to wind up the clinical trial.
The biopharma company is yet to share data from the trial but plans to do so at an upcoming scientific meeting. As well as spleen volume, Incyte was looking at changes in symptom scores, overall survival and adverse events across a set of secondary endpoints.
Incyte’s statement makes no mention of the development of parsaclisib in other indications. Other phase 3 trials are testing the drug candidate as a monotherapy in patients with warm autoimmune hemolytic anemia—a disease for which there are no approved drugs—and in combination with Jakafi as a first-line treatment for myelofibrosis. Incyte abandoned plans to seek approval in lymphoma early last year.
The failure of parsaclisib to help non-responders to Jakafi still leaves Incyte with open R&D avenues. In the second half of the year, the company expects to share updated data from trials that are evaluating the effect of adding an ALK2 inhibitor, zilurgisertib, and a BET inhibitor, INCB057643, to Jakafi.