Improved tolerability and quality of life with maintained efficacy using twice‐daily low‐dose interferon‐α‐2b

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Abstract
BACKGROUND.: In vivo data have shown a more potent antiangiogenic effect and a higher antitumor activity of low‐dose interferon (IFN) given twice daily. In a randomized Phase II trial, the authors tested the hypothesis that twice‐daily low‐dose IFN is more effective than daily intermediate‐dose IFN in patients with metastatic renal cell cancer (MRCC).METHODS.: A total of 118 patients (59 per arm) were randomly assigned to receive IFN at a dose of 0.5 million units (MU) given subcutaneously twice daily (IFN1) or IFN at a dose of 5 MU given subcutaneously daily (IFN5). The primary endpoint was progression‐free survival (PFS). Secondary endpoints included response rate (RR), overall survival (OS), toxicity, and quality of life (QOL).RESULTS.: There were no significant differences in either PFS or OS between IFN1 and IFN5 (median of 3.7 months and median of 3.4 months PFS, respectively; median of 25.5 months and median of 17.5 months OS, respectively). The RRs were identical in the 2 arms (6.7%; 95% confidence interval [95% CI], 1.8–16.5%). Two patients, 1 in each arm, remained in complete remission at the time of last follow‐up, at 45+ and 38+ months from treatment. Thirty‐two patients receiving IFN5 and 19 patients receiving IFN1 experienced Grade 3 or higher adverse events (graded using the National Cancer Institute Common Toxicity Criteria [version 2.0]) (P= .025). Eighteen patients receiving IFN5 and 4 patients receiving IFN1 had dose reductions (P= .002). There was a significant deterioration in QOL and an increase in depression associated with IFN5 but no change was noted with IFN1.CONCLUSIONS.: Compared with IFN5, IFN1 is neither more nor less effective but is less toxic, with a better reported QOL. These results may have implications for the design of combination regimens incorporating IFN with targeted agents. Cancer 2006. © 2006 American Cancer Society.