CHICAGO—Axitinib may provide better outcomes than sorafenib as second-line treatment for patients with metastatic renal cell carcinoma (mRCC) previously treated with cytokines, according to a new study.

In a phase 3 trial, patients who received axitinib experienced a near doubling of median progression-free survival (PFS) compared with those who received sorafenib, investigators reported at the American Society of Clinical Oncology annual meeting.

“The take-home message is that axitinib is a second-generation TKI [tyrosine kinase inhibitor] that is very active in the treatment of metastatic renal cell carcinoma and should be strongly considered as a standard of care for patients with advanced renal cancer,” said lead study investigator M. Dror Michaelson, MD, Assistant Professor of Medicine at Massachusetts General Hospital Cancer Center in Boston. “It has very impressive efficacy and it generally very well tolerated by the patients.”

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He noted that this study is one of the first to compared two TKIs head to head.

Dr. Michaelson and his colleagues presented findings of a subset analysis of mRCC patients who received cytokines as first-line therapy. The researchers enrolled 723 patients with clear-cell mRCC and progressive disease after one systemic therapy. Among these patients, 251 received prior interleukin-2 (IL-2) or interferon-α (IFN-α).  Patients were randomized to receive axitinib (5 mg twice daily starting dose) or sorafenib (400 mg twice daily). The mean age of the patients in the axitinib group was 61 years (range 20-82 years) and 75% were male. The mean age of the patients in the sorafenib group was 60 years (range 35-79 years) and 69% were male.

As of June 2, 2011, the median PFS for cytokine-treated patients was 12.0 months (range 10.1- 13.9) with axitinib versus 6.6 months (range 6.4- 8.3 months) with sorafenib.  For those treated with an IL-2-containing regimen, the median PFS was 15.7 months (range 8.3-19.4) with axitinib versus 8.3 months (range 4.7-15.7 months) with sorafenib.

For those treated with IFN-α alone, the median PFS was 12.0 months (range 10.0 -13.8) with axitinib versus 6.5 months (range 6.4-8.2) with sorafenib. As of November 1, 2011, the median overall survival in the cytokine-treated subgroup was 29.4 months with axitinib compared with 27.8 months with sorafenib.

With respect to adverse events, fatigue, dysphonia, and hypothyroidism were more common with axitinib, whereas hand–foot syndrome, alopecia, and rash were more common with sorafenib.  In all, seven patients (5.6%) previously treated with cytokines discontinued axitinib and nine (7.3%) discontinued sorafenib due to toxicity. Of patients previously treated with cytokines who discontinued treatment with axitinib or sorafenib, 46% in each arm received follow-up systemic therapy.