Phase II study of interferon alfa-2a, recombinant (Roferon-A) in metastatic renal cell carcinoma.

In an attempt to decrease toxicity without compromising efficacy, 22 patients with locally advanced or metastatic renal cell carcinoma (RCC) were treated with recombinant interferon alfa-2a (rIFN alpha 2a, Roferon-A; Hoffman-LaRoche, Nutley, NJ) intramuscularly (IM) beginning at a dose of 3 X 10(6) U/d with incremental dose escalations to the highest dose of 36 X 10(6) U/d if tolerated, for a total induction period of 10 weeks. Patients demonstrating complete (CR), partial (PR), or minor (MR) responses or stabilization were continued on a maintenance regimen of the highest tolerated dose administered three times weekly until disease progression. Doses administered during maintenance were individually determined as the maximum dose that resulted in only mild toxicity. No CRs were achieved. Partial responses were observed in 23% of the patients with a median duration of response of 8.0 months (range, 1 to 17+). The majority of interferon side effects were seen during the induction phase, which was also the period requiring the most frequent adjustments in dose. In comparison to another study using similar toxicity criteria, overall toxicity was reduced in severity, most probably due to the study design, which allowed individual tailoring of doses. The use of an initial induction phase employing rapid dose escalation followed by a well-tolerated maintenance phase appeared to be a reasonable strategy. The therapeutic results to date represent a modest advance. An optimal dosage, route, and schedule for interferon administration for metastatic renal cancer is not yet clearly established.