Seragen Inc. and BioCryst Pharmaceuticals Inc. presentedinformation Thursday on their psoriasis drug candidates, and bothcompany's stock prices increased on the updates.
Data from Seragen's interleukin-2 (IL-2) fusion toxin molecule werepresented at the Cytokine Therapy Conference in Washington. Theinvestigator reported on four patients treated with 300 kU/kg doses,the highest for which data is available, who had a 53 percent meanreduction from baseline in disease severity scores at the end of threecourses.
BioCryst, of Birmingham, Ala., presented additional data on its drug,BCX-34, for psoriasis and cutaneous T cell lymphoma (CTCL) _ aswell as interim data from an open-label study in CTCL _ at adermatology seminar in Hawaii.
While the product candidates from Seragen and BioCryst have anumber of differences, they both target T cells. A number ofcompanies discontinued development of psoriasis candidates in thepast few years, including Chemex Pharmaceuticals Inc., of Fort Lee,N.J., Agouron Pharmaceuticals Inc., of La Jolla, Calif., and SphinxPharmaceuticals Corp., of Durham, N.C.
Seragen's stock (NASDAQ:SRGN) was up 50 cents Thursday,closing at $5.50. BioCryst (NASDAQ:BCRX) was up 38 cents to$6.50.
One interesting aspect of Seragen's Phase I/II the BioCryst study wasthat specific cleared skin sites appear to have been restored tonormal, unlike other therapies in which clearing did not result innormal cellular structure, said James Krueger, who conducted thetrial at the Rockefeller University Laboratory for InvestigativeDermatology.
Overall, in all patients at all dose levels, the Psoriasis Area andSeverity Index (PASI) scores decreased from baseline by a mean of32 percent after two courses. The PASI score decreased by a mean of46 in the 12 people who completed three courses. Those tested hadreceived an average of five other therapies before treatment with theIL-2 fusion toxin.
Fusion toxins consist of a toxin fragment genetically fused to ahormone or growth factor that targets specific cell-surface receptorsor disease-causing cells. Seragen, of Hopkinton, Mass., iscollaborating with Eli Lilly and Co., of Indianapolis, on all cancerindications, including CTCL, where they are just starting a Phase IIIstudy of IL-2 fusion toxins. Seragen, of Hopkinton, Mass., has rightsin dermatological areas.
"The four patients treated with the higher dose had very goodresults," said Helen Maslocka, Seragen's vice president for investorrelations/corporate communications. "We're excited about that,particularly because these patients had failed everything else."
She said Seragen hopes to be in a controlled Phase II study by mid-year that would be finished by the end of the year.
BioCryst has Phase II trials ongoing of BCX-34 in psoriasis andCTCL. It is a small molecule designed to inhibit proliferation of Tcells by targeting the enzyme, purine nucleoside phosphorylase.
John Higgins, BioCryst's director of corporate development, saidparameters such as redness, scaling, thickness, patients' evaluations_ rolled into a global score _ showed a 56 percent improvement vs.baseline among 34 evaluable patients.
BioCryst tested four doses ranging from .1 to 5 percent, and didn'tsee any significant differences in the doses. Therefore, he said,another Phase II study is being planned in which lower doses will beanalyzed. The trial is expected to be larger and longer than the initialPhase II, Higgins said. He said another Phase II would have beenconducted regardless of the results.
At the end of the CTCL study, 25 of 29 patients volunteered to go oninto an open-label study. Nineteen patients had reached the three-month mark. Higgins said four of those had cleared completely, threeare almost clear (greater than 75 percent), eight have definiteimprovement, three possible improvement, none had no change andone is possibly worse.
The drug was granted orphan status for the CTCL indication. "Wewould like to pick a dose from this trial we believe is dependable toinitiate a Phase II/III study," Higgins said. n
-- Jim Shrine
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