By Randall Osborne
The day after Seragen Inc. filed a biologics license application (BLA) with the FDA for its pioneering lymphoma treatment, the company presented results from the Phase III trial on which the application was based, and the data are strongly positive.
"Earlier, we thought the time frame [between filing and making the data public] would be a little wider," said Jean Nichols, president and chief technology officer of Seragen, shortly before she presented the Phase III data to the annual meeting of the American Society of Hematology in San Diego. "We've been working on the submission for a while."
Seragen's Interleukin-2 (IL-2) Fusion Protein to treat recurrent or persistent cutaneous T cell lymphoma (CTCL) is not only the first BLA to be filed by the company; if approved, it also will be the only drug marketed against the deadly and disfiguring disease. (See BioWorld Today, Dec. 9, 1997, p. 1.)
"We're not saying we have a cure," Nichols said of IL-2 Fusion Protein, or DAB389IL-2. "I'm saying it's a critical medical need area, and there's nothing approved." Seragen, of Hopkinton, Mass., has asked the FDA for expedited consideration of the filing.
The Phase III trial was designed to measure the safety and efficacy of treatment for CTCL patients whose disease recurs or persists despite prior treatments, such as chemotherapy, light therapy, electron beam radiation, interferon, or some combination.
"Most therapies are considered palliative, especially in the later-stage disease," Nichols said.
The trial studied 71 patients in whom an average of five prior therapies had failed, and used a range of criteria. "We're looking at classic methods to measure reduction of tumor burden, but we've also incorporated a number of measures of symptomatology," including improvement in quality of life, Nichols said.
"The whole body can be involved," she added. "The face can be very disfigured."
Overall, preliminary analysis of the data suggests that 30 percent of patients treated with DAB389IL-2 showed a 50 percent or greater reduction in tumor burden lasting at least six weeks, which is consistent with the findings of the earlier Phase I/II study. These patients were classified as responders. About 10 percent showed complete resolution of all evidence of tumor.
Symptoms improved in all responders, and in 80 percent of those who did not fall in the responder category. Statistically significant differences were noted in four measures of quality of life for responders as compared with non-responders.
Adverse events, however, were noted. These included hypersensitivity and infusion-related effects, flu-like symptoms and a vascular leak disorder. Acute cases were treated by slowing the rate of drug infusion and administering antihistamines. Some patients developed rashes.
Patients mostly were older people with advanced-stage disease who had undergone multiple prior therapies, and 37 percent of them withdrew because of adverse events including infections, cardiovascular changes such as unstable angina and arrhythmia, and neurological changes such as confusion and amnesia.
Seragen's stock (OTC Bulletin Board:SRGN) closed Tuesday at $0.490, unchanged. *