By Randall Osborne
An independent panel reviewed early data from Ribi ImmunoChem Research Inc.'s Phase III trial of its Melacine melanoma therapeutic vaccine combined with Intron A (interferon alpha-2b) and said the study should continue.
The unanimous vote by the Data and Safety Monitoring Board came just over a week after Hamilton, Mont.-based Ribi sealed a potential $30 million marketing deal with Schering-Plough Corp., of Madison, N.J., for Melacine as a monotherapy. (See BioWorld Today, March 17, 1998, p. 1.)
"We get very good results in those people who are responders [to Melacine alone]," said Robert Ivy, president and CEO of Ribi. "The problem is the response rate runs about 20 percent."
Schering already markets Intron A, which is approved for early-stage melanoma, as well as various viral diseases and cancers.
At the time of the interim review of data, the study of Melacine with Intron A had accrued 168 patients with Stage IV melanoma, which is the most advanced form of the malignancy.
The monitoring board reported no safety concerns, and full accrual is expected by the end of this year, with final analysis 12 months later.
In the combination therapy study, the primary endpoint is overall survival. Secondary endpoints include clinical response rates as measured by tumor regression, safety and toxicity, in addition to quality of life.
An already completed Phase III study of Melacine as a monotherapy in Stage IV melanoma patients showed improved quality of life, but not survival. (See BioWorld Today, May 21, 1997, p. 1.)
"Intron [alone] is associated with a lousy quality of life," Ivy said.
"The combination, by inference, is working better [than monotherapy]," he said. "It's not that we're going to look to one or the other. What we're trying to do is cover the waterfront, and maintain quality of life. We're titrating up to the maximum tolerable dose, and then backing off a little bit."
Ivy said the best treatment strategy will likely turn out to be Melacine as a monotherapy first, adding Intron A if the response is not adequate. Ribi has filed for approval of Melacine as a monotherapy in Stage IV melanoma in Canada and Europe.
"We'll file with the FDA mid-year [for the monotherapy], and have it on the market in 1999 in the U.S.," Ivy said.
Ribi's stock (NASDAQ:RIBI) closed Wednesday at $5.187, down $0.375. *