Update: Abbott says atrasentan trial misses endpoint

Abbott Laboratories has halted a Phase III trial of one its late-stagepipeline drugs, atrasentan for prostate cancer, after the study failed to meet its primary endpoint. Atrasentan, formerly known as ABT-627, is an investigational selective endothelin-A receptor antagonist.

Abbott said that the drug failed to show an improvement in time to disease progression in the 810-patient study, which enrolled individuals with end-stage, metastatic, hormone-refractory prostate cancer. However, the company said that other Phase III trials of atrasentan in this indication, and Phase II studies in other tumor types, will continue.

Abbott said there were some signs of a positive effect in the study, particularly on prostate-specific antigen bone markers of the disease, and pointed out that those enrolled were very sick and in the end-stage of their illness. The news came as a disappointment, though, as atrasentan has been held up as part of a trinity of new drugs that Abbott expects to drive growth over the next few years. The others are Humira (adalimumab), its recently-approved anti-tumor necrosis factor antibody for rheumatoid arthritis, and the HIV protease inhibitor Kaletra (lopinavir plus ritonavir).