BioWorld International Correspondent
Responding to last week's rebuff by the FDA's Oncologic Drugs Advisory Committee (ODAC), GPC Biotech AG withdrew its NDA for accelerated approval of satraplatin in hormone refractory prostate cancer.
The Martinsried, Germany-based firm said Monday it would resubmit an NDA with overall survival data from its 950-patient Phase III clinical trial, following ODAC's 12-0 vote against recommending approval of the drug based on progression-free survival data.
"Administratively, we think that it's the best and cleanest approach to submit a new application," GPC director of investor relations and corporate communications, Martin Braendle, told BioWorld International. "A new application would allow us to refocus the data around overall survival."
The company also is digesting the wider implications of the setback. "We are evaluating potential cost-cutting measures," Braendle said. "I cannot go into details here."
GPC's bid to obtain accelerated approval for satraplatin, based on progression-free survival, foundered on the FDA's decision not to accept the novel composite PFS endpoint designed by GPC, even though individual elements of it had been employed in prior drug approvals.
The move will have little impact on the timing of the approval process, Braendle added. The ongoing Phase III trial is powered to demonstrate an impact on overall survival once 700 deaths have occurred in the study group. "We expect to have topline overall survival data from the required 700 deaths available in the next six months," he said. Approximately 650 deaths already have occurred.
If those data are favorable, approval could follow in another six months - about one year later than the company's original expectations. Earlier this year, GPC raised €33.6 million (US$43.7 million) in a private placing to fund the creation of a sales and marketing organization in advance of an anticipated launch of satraplatin.
Although initially surprised by the move, Martin Possienke, analyst at Frankfurt, Germany-based Equinet Institutional Services AG, saw merit in the move. "It makes sense to me that they prefer to supply the FDA with a clean document," he told BioWorld International. The company will be able to build its lines of argument around the survival data - and that will be particularly important, he added, if the data fail to demonstrate statistical significance, while demonstrating clear trends in support of survival.
The recent collapse in GPC's share price (Frankfurt: GPC; NASDAQ:GPCB) - it dropped from €23.14 to a low of €7.57 in Frankfurt over the past two weeks - has opened up a potential buying opportunity on the stock. "I think the stock was definitely overvalued before," Possienke said. "Maybe the current pricing is not fair."
Prior to the ODAC hearing, he had a hold recommendation on the stock, with a target price of €20, based on an 80 percent probability of satraplatin reaching the market. He now has a target price of €16, based on a 60 percent probability of success. "The drug is not dead; it's just postponed."
By late afternoon Tuesday, GPC's stock was trading at €9.64 in Frankfurt, up more than 9 percent on Monday's close of €8.78.