Washington Editor

GPC Biotech AG said the FDA gave it the go-ahead to begin a Phase III registration trial for its lead compound, satraplatin, as second-line chemotherapy in hormone-refractory prostate cancer.

If all goes according to plan, GPC and its co-development partner, Spectrum Pharmaceuticals (formerly NeoTherapeutics Inc.), expect to file a new drug application in 2006.

Tuesday's news followed a successful special protocol assessment and "end of Phase II" meeting with the FDA, in which the company and government discussed the safety of the drug regimen and the proposed Phase III.

Satraplatin, an oral drug, is part of the platinum family of compounds. GPC's pending Phase III will match satraplatin plus prednisone against prednisone alone in a trial expected to enroll patients numbering in the mid-to-high hundreds. Prednisone is a synthetic hormone often used to treat advanced cancer.

"Hormone-refractory prostate cancer represents an area of major unmet medical need," Marcel Rozencweig, senior vice president, drug development of Munich, Germany-based GPC Biotech, said in a prepared statement. "For patients with this disease who fail one chemotherapeutic regimen, there are currently no approved treatment options. Together with our colleagues at Spectrum Pharmaceuticals, GPC Biotech is moving forward aggressively with the development and registrational plans for satraplatin."

Company officials believe Phase III data will provide enough information for regulatory filing, particularly since satraplatin performed well in a previous smaller Phase III.

Laurie Doyle, GPC's senior manager, investor relations and corporate communications, told BioWorld Today satraplatin plus prednisone produced statistically significant results in a 50-patient Phase III trial conducted by the European Organization for Research and Treatment of Cancer. Results were presented at the American Society of Clinical Oncology annual meeting in June.

Doyle said the 50-patient, randomized trial evaluated satraplatin as a first line of chemotherapy. The median time to disease progression was 5.2 months in the treatment arm vs. 2.5 in the control arm, she said.

At six months, 41 percent of the patients in the treatment arm were progression-free vs. 22 percent in the control arm.

The pending Phase III is modeled after the smaller trial with an accelerated approval endpoint of time to disease progression. The study's objectives also will include the evaluation of pain control and survival, as well as an assessment of drug safety in this population.

The first dosing will trigger a $1 million cash payment and $1 million equity payment from GPC to Spectrum.

Spectrum licensed satraplatin, a third-generation platinum analogue, to GPC in a deal valued at $22 million in October. GPC, which owns worldwide rights to satraplatin, paid a $2 million up-front fee. (See BioWorld Today, Oct. 2, 2002.)

Spectrum, under the name NeoTherapeutics, acquired satraplatin in September 2001 from Johnson Matthey plc, a London-based company that developed the compound in conjunction with Bristol-Myers Squibb Co., of New York.

Spectrum restructured its business about a year ago, cutting about half its staff while reducing the burn rate to about $500,000 per month. The company's trouble started when its Alzheimer's candidate, Neotrofin (leteprinim potassium), failed to meet its primary endpoints in a 12-week pivotal Phase III trial. (See BioWorld Today, Aug. 23, 2002, and April 30, 2002.)

Doyle said GPC likely will seek one or more marketing partners for satraplatin.