While adjuvant axitinib failed to improve disease-free survival in a recent phase 3 renal cell carcinoma (RCC) trial, the highest-risk subgroup appeared to benefit, according to a report on the study.
The phase 3 ATLAS trial was stopped early because of a lack of benefit for axitinib versus placebo in the study, which included patients with locoregional RCC at risk of recurrence after nephrectomy.
However, a prespecified analysis showed that axitinib reduced risk of disease-free survival events by about one-third in the highest-risk subset of patients, according to investigator David I. Quinn, MD, USC Norris Comprehensive Cancer Center, Los Angeles, and colleagues.
That finding tracks with results of the earlier S-TRAC trial, in which patients at high risk of tumor recurrence after nephrectomy had significantly longer disease-free survival with sunitinib versus placebo, Dr. Quinn and coauthors said.
“Taken together, these results support that patients at highest risk for RCC recurrence benefit from adjuvant treatment,” they wrote in.
In the ATLAS trial, Dr. Quinn and coinvestigators at 137 centers in eight countries enrolled 724 adults with newly diagnosed renal cell carcinoma (greater than or equal to pT2 and/or N+, any Fuhrman grade) with Eastern Cooperative Oncology Group status of 0 or 1 and prior nephrectomy.
Patients were randomly assigned to oral, twice-daily axitinib 5 mg or placebo for up to 3 years of treatment, and at least 1 year of treatment provided there was no recurrence, substantial toxicity, or withdrawal of consent.
For the primary endpoint, disease-free survival per independent review committee assessment, the hazard ratio was 0.870 (95% confidence interval, 0.660-1.147; P = .3211), according to the report. Disease-free survival as rated by investigators showed a somewhat larger but still not statistically significant reduction in risk of an event, Dr. Quinn and colleagues said.
However, in the prespecified subgroup analyses, the patients at highest risk (pT3 with Fuhrman grade greater than or equal to 3 or pT4 and/or N+, any T, any Fuhrman grade) had a reduction of risk with hazard ratios of 0.735 per independent review committee (P = .0704) and 0.641 per investigator (P = .0051).
The ATLAS study was designed before results of the S-TRAC study were known, and so patients at lower risk of recurrence were included, said Dr. Quinn and coauthors.
Ongoing trials are looking at sorafenib, everolimus, and immune checkpoint inhibitors in the adjuvant RCC setting, they noted in their discussion of ATLAS, S-TRAC, and other investigations.
Results from these trials may provide clarification on the future of adjuvant treatment for RCC, and whether angiogenesis inhibition is the key mechanism to obtain a reduction in risk of relapse after nephrectomy,” they said.
The study was sponsored by Pfizer and SFJ Pharmaceuticals. Dr. Quinn reported providing advisory board services for Pfizer, Bayer, Novartis, Bristol-Myers Squibb, Merck, Exelixis, Genentech, Roche, AstraZeneca, and Astellas. Coauthors reported disclosures related to Bristol-Myers Squibb, Ipsen, MSD, Novartis, Pfizer, and Roche, among others.
SOURCE: Quinn DI et al. Ann Oncol. 2018 Oct 20. .