By Mary Welch
On the advice of an independent monitoring board, Berlex Laboratories Inc. halted a Phase IV U.S. trial of Betaseron (interferon beta-1b) for secondary-progressive multiple sclerosis (SPMS), but the company can't quite say if that was good news or bad news.
"It's sort of middle-of-the road news," said Wendy Neininger, director of corporate communications at Montville, N.J.-based Berlex.
"When we got the letter from the board, I called up the chairman and asked what it meant," said Jeffrey Latts, vice president of clinical research and development at Berlex. "It's ambiguous. I asked if they were stopping it because the trial was good or bad and he said he wasn't saying."
Betaseron was approved in 1993 for relapsing-remitting multiple sclerosis. It is partnered with Chiron Corp., of Emeryville, Calif. However, about half of those patients develop SPMS, a more severe and debilitating form of multiple sclerosis.
The companies started a trial testing Betaseron for SPMS in 1996 with a parallel study in Europe. The European trial was stopped early when it showed highly significant benefit. Upon the success of that trial, Berlex and Chiron filed a supplemental new drug application for the indication.
However, the U.S. trial was still under way, with a completion date of March 2000. Some 935 patients were to be enrolled in the three-arm trial.
The monitoring board determined the probability was very small that the primary outcome would change much if preliminary data were released now instead of in March. Therefore, the board recommended that the placebo-controlled study continue until every patient received the final dosage.
As a result of the ruling, clinical investigators will continue to compile data until all patients make their final visits.
In addition, the board recommended that all patients enrolled in the study be given the opportunity to receive Betaseron and will be medically monitored. Berlex is providing Betaseron at no cost to those patients.
"What they're saying is that the best way to preserve the credibility of the final trial is for no one to know its outcome until all the data are compiled. We're about halfway through all the patients having their final visits," Latts said. "I can understand that. I'm curious about the data but we decided to take their advice. But there has been a lot of money spent on this trial and we want it to be as strong as possible."
After the trial is completed and the results unblinded, they will be given at a major scientific meeting by mid-summer, Latts said.
"We've already filed with the FDA, and it is possible that they could act on the European results," he said. "But, more likely, the FDA will wait for our results. We're keeping the door open."
Berlex is a subsidiary of Schering AG, of Frankfurt, Germany. Chiron's stock (NASDAQ:CHIR) gained 3 cents Monday to close at $34.812.