Roche’s Genentech subsidiary today trumpeted successful second-stage Phase III results for its GA101 or obinutuzumab for the blood cancer chronic lymphocytic leukemia (CLL), saying the drug candidate plus chlorambucil resulted in “significantly” longer progression-free survival (PFS) compared with its previous-generation version, Rituxan (rituximab) plus chlorambucil.
Genentech did not detail what PFS was in the second stage of its CLL11 study, saying those results have been submitted for presentation at the 55th Annual Meeting of the American Society of Hematology, to be held December 7–10 in New Orleans. The company did say, however, that the study’s independent data monitoring committee determined that the study met its primary endpoint—and that final data on the improvement shown by obinutuzumab plus chlorambucil arrived well ahead of the study’s 2014 target completion date “as a result of the magnitude of difference seen between the two study arms.”
“The positive final results from the CLL11 study show the promise that GA101 could hold for people with CLL,” Hal Barron, M.D., Genentech’s CMO and head, Global Product Development, said in a statement. “It is important to explore the potential of this medicine in other types of blood cancer, and our broad development program includes studies in aggressive and indolent lymphoma that compare GA101 with Rituxan.”
The second-stage study assessed 781 previously untreated people with CLL and co-existing medical conditions who are in need of therapy. Earlier this year, Genentech released first-stage Phase III results showing that in 589 patients studied, obinutuzumab plus chlorambucil more than doubled the PFS of chlorambucil alone, 23 months compared with 10.9 months. CLL11 was a multicenter, open-label, randomized three-arm study conducted in cooperation with the German CLL Study Group.
The first-stage results were promising enough for Genentech to gain both a Breakthrough Therapy Designation and Priority Review from FDA. Genentech submitted marketing applications for obinutuzumab to FDA and the European Medicines Agency in April, following release of the first-stage results.
According to Genentech, obinutuzumab is the first glycoengineered type II anti-CD20 medicine, with changes to the structure of sugar molecules designed to improve interaction with immune cells and create an antibody that acts as an immunotherapy against cancerous cells. The drug candidate is intended to induce direct cell death by binding to CD20.
Rituxan generated CHF 6.7 billion (about $7.2 billion) in sales for Roche last year—a figure expected to fall in coming years due to expected competition from biosimilar drugs. Obinutuzumab’s strong Phase III results in CLL “bode well for a potential efficacy in other types of blood cancer,” Helvea analyst Odile Rundquist told investors in a note reported by Bloomberg that also estimated GA101 will rack up CHF 1.15 billion ($1.23 billion) in annual sales.