Updated from 7:38 a.m. EST
suspended new recruitment in a year-old trial of its Avastin drug in colon cancer after several patients in the study died.
Genentech and its majority owner,
of Switzerland, announced the suspension of the international trial enrollment after seeing a higher incidence of deaths unrelated to colon cancer in subjects taking Avastin plus a chemotherapy regimen called Xelox.
The study, dubbed "Avant," was designed to measure Avastin's efficacy in conjunction with two chemotherapies, Xelox and Folfox, and on its own.
According to Genentech, the data safety monitoring board recommended that the company halt enrollment based on a higher number of deaths in the Xelox/Avastin arm of the study compared with the other two arms of the study, Avastin by itself and with the chemotherapy regimen Folfox.
"Due to the rapid enrollment of patients in the Avant study and the ongoing need to carefully monitor safety, we believe that the data safety monitoring board's recommendation to temporarily suspend enrollment in the study is the right thing to do for patients in order to enable a more detailed analysis of safety data," Genentech said.
Four deaths were reported in patients taking Folfox alone, and three were reported in the Folfox plus Avastin group. Seven deaths occurred in the Avastin and Xelox arm of the trial.
Studies are ongoing in more than 2,000 patients recruited into the phase III trial since December 2004.
While it's possible that the company could decide to discontinue the Xelox arm of the trial, some analysts say it might not even come to that because the number of additional deaths in that arm aren't significant.
"The seven cases would not be beyond the safety threshold to discontinue the arm or the trial," Ron Ellis, a biotech analyst at Prudential Equity Group, wrote in a research report Monday.
Ellis expects the trial to reopen for enrollment after a 60-day review. Genentech will still follow through with a U.S. trial of Avastin plus Folfox, compared with Folfox alone, in a group of post-surgery later-stage colorectal cancer patients. Unlike the Avant study, this trial doesn't include a Xelox arm.
"This decision further underscores the belief that the safety concerns seen in Avant are limited to Xelox plus Avastin," according to Rodman & Renshaw's Mike King.
Avastin is already approved as a first-line treatment of metastatic colorectal cancer. The suspended study was reviewing the drug as a so-called adjuvant therapy designed to prevent the cancer from recurring.
Genentech's shares fell $2.04, or 2.4%, to $81.48 Monday.