By Mary Welch
Chiron Corp. said the R.W. Johnson Pharmaceutical Research Institute stopped enrollment of a Phase III efficacy study of Regranex (becaplermin) gel for pressure ulcers.
Although no specifics were given, Chiron, based in Emeryville, Calif., said the decision was based on interim data from a Phase III study that do not support the previous positive Phase II results.
"The enrollment has been halted but, because there were no safety issues involved, the blinded study will continue in order to collect additional data which will be used to assess how to move forward," said Julie Wood, director of investor relations and corporate communications for Chiron. "The reason it was stopped was that the interim data do not support the efficacy data from the Phase II. They are inconsistent and so no conclusions can be drawn until we collect more information. It's premature to speculate as to when we'll make a decision on how to proceed."
Regranex was approved by the FDA in 1997 for the treatment of diabetic foot ulcers or sores, the first genetically engineered would-healing agent. Regranex was developed by Chiron and Ortho McNeil Pharmaceutical, of Raritan, N.J. - like R.W. Johnson a subsidiary of Johnson & Johnson, of New Brunswick, N.J. Chiron supplies the active ingredient, which is a recombinant human platelet- derived growth factor (PDGF). (See BioWorld Today, Dec. 18, 1999, p. 1.)
"It's disappointing," said David Molowa, senior analyst with Bears Stearn & Co. Inc. in New York. "It definitely limits the drug's ultimate marketing potential. Pressure ulcers are a sizeable part of the wound-healing market. Obviously they will not be using the gel for this indication and any off-label usage, which was based on the positive Phase II results, will have to stop."
The efficacy results were inconsistent with the Phase II results that were published in the May-June issue of Wound Repair and Regeneration. Article reprints on the study will no longer be distributed, the company said.
Molowa did not know the exact reason why the trial was stopped but he allowed, "It's a very difficult area because of the high placebo rates. If you take good care of a wound, they tend to heal better, which makes it difficult to statistically prove the effect of the drug. I'm not sure if that is the case here, but similar situations have occurred with previous drugs for wounds."
Chiron's stock (NASDAQ:CHIR) closed Tuesday at $28.312, down $3.562, or 11 percent.