Axitinib shows survival benefits in metastatic RCC
medwireNews: Axitinib treatment appears to lengthen progression-free survival (PFS) compared with sorafenib, making it a viable second-line treatment option for patients with metastatic renal cell carcinoma (RCC), say investigators.
They note that overall survival, a secondary endpoint of their study, did not differ significantly between the two groups, whereas median investigator-assessed PFS was 8.3 months among patients treated with axitinib, compared with 5.7 months among those taking sorafenib.
"Results of this study substantiate axitinib as a treatment option in previously treated patients with metastatic renal cell carcinoma…, and showed axitinib to have better efficacy in PFS compared with an active competitor, sorafenib," investigator Robert Motzer (Memorial Sloan-Kettering Cancer Center, New York, USA) and colleagues comment.
The researchers analyzed data on 723 patients with metastatic RCC who were participating in the randomized phase III Axitinib Second-line (AXIS) trial. The patients were randomly assigned to receive axitinib (n=361) 5 mg twice daily or sorafenib (n=362) 400 mg twice daily.
The median overall survival was 20.1 months for patients treated with axitinib and 19.2 months for those treated with sorafenib. In both treatment groups, overall survival seemed longer in patients who had received previous cytokine treatment compared with previous sunitinib treatment.
The researchers found that both tyrosine kinase inhibitors demonstrated favorable safety profiles, but they detected differences in the relative incidence of some treatment-related adverse events. For example, those occurring most commonly in axitinib-treated patients were diarrhea, hypertension, and fatigue, whereas in sorafenib-treated patients, they were diarrhea, hypertension, and hand-foot syndrome.
Patient-reported outcomes as assessed by the Functional Assessment of Cancer Therapy Kidney Symptom Index (FKSI-15) and FKSI-Disease-related Symptoms subscale were similar between the two treatment groups at baseline and were maintained during treatment, but decreased toward the end of treatment.
"Therefore, an improvement in symptoms or quality of life would not be expected," say the researchers in TheLancet Oncology. "Because patients treated with axitinib had longer PFS than did those treated with sorafenib, patients in the axitinib group seemed to have longer symptom maintenance or control."
Patients who developed hypertension - diastolic blood pressure of 90 mmHg or above and systolic blood pressure above 140 mmHg - during the first 8 to 12 weeks of treatment were a respective significant 37% and 51% more likely than patients with lower blood pressure values to survive longer, but there was no effect on PFS.
Other possible prognostic variables were identified but rather than being treatment related were "indicative of a more aggressive underlying renal cell carcinoma phenotype," says the team, and therefore "not yet applicable for choosing one agent versus another."
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By Lucy Piper, Senior medwireNews Reporter