ZymoGenetics, Inc. (ZGEN) announced that an oral presentation and 2 posters concerning Interleukin 21 (IL-21), a potential treatment for cancer, were given at the recent American Society of Clinical Oncology (ASCO) 2005 annual meeting held in Orlando, Florida.

Brendan Curti, MD, of Providence Portland Medical Center, summarized results from the treatment of the first 12 patients in a phase 1 study of IL-21 as treatment for metastatic melanoma and renal cell carcinoma.

Curti reported that IL-21, administered in an outpatient setting, showed evidence of anti-tumor activity and was reasonably well tolerated with reversible toxicities. One patient with metastatic renal cell carcinoma achieved a partial response that continues at more than 7 months of follow-up and 6 patients had at least stable tumor measurements after 2 cycles of treatment.

No antibody response against IL-21 was detected, and there was dose dependent immune cell activation that was consistent with nonclinical studies. Dose escalation in the phase 1 study is continuing to determine the maximally tolerated dose of IL-21.

Primary objectives of the open label phase 1 dose escalation study are to assess safety and determine the maximum tolerated dose of IL-21. Secondary objectives are to assess pharmacokinetics, immunogenicity and other clinical or biological parameters that may correlate with anti-tumor activity. All 12 patients treated had tumors that had metastasized (stage IV); 8 of the 12 had malignant melanoma and 4 had renal cell carcinoma. Two cycles of 5 daily intravenous doses of 3, 10 or 30 micrograms per kilogram were separated by a 9 to 16 day rest period. Two of the twelve patients were given 2 additional 5-day cycles of IL-21, for a total of 4 cycles.

For patients receiving 2 dose cycles, all of the drug-related adverse events were mild to moderate and were completely reversible. One patient who received 4 cycles of treatment at the highest dose developed acute hepatic injury at the end of the fourth cycle, which resolved completely, with hepatic function returning to normal, after drug administration was stopped.

Curti's presentation, "Preliminary tolerability and anti-tumor activity of intravenous recombinant human Interleukin 21 (IL-21) in patients with metastatic melanoma and metastatic renal cell carcinoma," is listed as ASCO Abstract No: 2502.

ZymoGenetics is a biopharmaceutical company focused on the discovery, development and commercialization of therapeutic proteins for the prevention or treatment of human diseases. This article was prepared by Drug Week editors from staff and other reports. Copyright 2005, Drug Week via NewsRx.com.

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