乌鸦传媒

MIAMI -- There was no statistically significant difference in survival outcomes between axitinib (Inlyta) and cabozantinib (Cabometyx) in metastatic renal cell carcinoma (mRCC) patients refractory to sunitinib (Sutent), researchers reported here.

A matching adjusted indirect comparison (MAIC) was used to adjust for imbalances in baseline characteristics between the axitinib arm of the AXIS trial and the cabozantinib arm of the METEOR trial, explained Irina Proskorovsky, of the research firm Evidera in Montreal, Canada, in a presentation at the International Kidney Cancer Symposium.

Her group compared progression-free survival (PFS) and overall survival (OS) in sunitinib-refractory patients. After matching, baseline characteristics were balanced between axitinib and cabozantinib patients, and no statistical difference was found in the estimated median PFS (7.8 and 9.1 months, respectively) and median OS (23.8 and 21.4 months, respectively).

Both agents are approved for second-line targeted therapy for mRCC, but there are no head-to-head trials that compare the relative efficacy of these agents, the authors pointed out.

They adjusted for differences in the two trial populations were adjusted for with MAIC. For example, in the AXIS trial, 74% of the participants were men, but after matching, the male participation was 79% to meet the demographic of the METEOR trial.

"Since Karnofsky performance score (KPS) was not collected in AXIS, a conversion from European Cooperative Oncology Group (ECOG) performance status was done to derive Memorial Sloan Kettering Cancer Center (MSKCC) score in order to compare patient prognosis between AXIS and METEOR," the authors stated.

They reported that, in sensitivity analysis, fewer AXIS patients fell into the MSKCC poor risk category and the estimated treatment effect for both PFS and OS trended towards favoring cabozantinib, but the results were not statistically significant.

Sumanta Pal, MD, of the City of Hope Comprehensive Cancer Center, Duarte, California, and scientific co-chair of the symposium told 乌鸦传媒 "I don't think that this is an optimal level of comparison, but it is what we have given the paucity of comparative data. I would suggest that in doing the sensitivity analysis, you are trying to correct for whatever difference there may be between these two populations to the best of your ability. This may be all that we ever have in this context."

"You really aren't supposed to compare across trials, but it is fun to do it," said Bradley Leibovich, MD, of the Mayo Clinic in Rochester, Minnesota, "However, in this case, the exercise may have found that one drug is better than another, but it may not really be relevant to how we are going to be practicing medicine in the near future."

Leibovich, who was not involved in the study, told 乌鸦传媒 that the field is moving to combining targeted agents and the the idea of using monotherapy in second-line treatment of metastatic renal cell carcinoma may be moot.