A Phase III trial of Ribi ImmunoChem Research Inc.'s Melacinemelanoma theraccine demonstrated no significant statistical advantageover a four-drug chemotherapy regimen in treating patients withdisseminated, or stage IV, melanoma.The study, with 70 patients in each arm, did not show significance ineither median survival or quality of life, Jeff McDowell, Ribi'scorporate information manager, told BioWorld."It was an important study, although it didn't turn out the way weanticipated, but the data is worthwhile," McDowell said. "I wouldguess that information will be prepared for publication."The news, released late Thursday, caused the company's stock(NASDAQ:RIBI) to drop 47 percent on Friday, from $7.50 to $4 pershare. The stock gained one-eighth Tuesday before closing down 6cents Wednesday at $4.06. Ribi has about 16.5 million sharesoutstanding."The market overreacted to the news," Wole Fayemi, seniorbiotechnology analyst for Hambrecht & Quist Inc., told BioWorld."Although this was the company's lead proprietary product, the core ofthe business is its vaccine adjuvant business, which from our projectionis responsible for the lion's share of revenue potential."Robert Ivy, the company's president, chairman and CEO, said Ribi hasabout $30 million in cash and equivalents, and pointed out it hasadjuvant licensing agreements with SmithKline Beecham plc andAmerican Cyanamid Co. McDowell said Ribi had about $1 million inrevenues last year from various licenses and other fees.Recurrence Trial Still ProceedingRibi, of Hamilton, Mont., has a separate, ongoing Phase III trial ofMelacine testing its ability to prevent recurrence of melanoma in stagetwo patients who have melanoma lesions surgically removed and inwhich the disease has not advanced. That trial is being sponsored bythe National Cancer Institute and conducted by the SouthwestOncology Group.McDowell said more than half of the 420 people in the study have beenenrolled. Half will receive Melacine; the control in the study isobservation. He said an interim analysis may be available by late 1995.Melacine also is being evaluated in combination with interferon alpha2-B (Schering-Plough Corp.'s Intron-A). A small study conducted atthe University of Southern California showed the combinationextended survival and enhanced tumor regression in late-stagemelanoma patients, compared with individual use of the agents.Melacine incorporates Ribi's Detox adjuvant with antigen derived fromhuman melanoma tumor cell lysates. It is intended to provoke an activeimmune response against melanoma.The stage IV patients treated with Melacine in the promising Phase IItrial had a median survival of about 20 months, McDowell said,compared to historic controls of about 12 months.Andrew Heyward, an analyst with Ragen MacKenzie Inc., of Seattle,told BioWorld the fact that the control group was not part of therandomized study "made the results less compelling." Fayemi said partof the problem came from the clinical trial structure."The company set overly aggressive endpoints, hoping for a 50 percentimprovement over the chemotherapy arm," Fayemi said. He said theresults didn't necessarily kill Melacine, or the possibility that Ribi willenter a partnership with Schering-Plough Corp. for the product. n

-- Jim Shrine

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