Pfizer Inc. has reported that phase 3 study of Inlyta (axitinib) did not meet its primary endpoint of demonstrating statistically significantly longer progression-free survival (PFS), versus sorafenib, in treatment-naïve patients with advanced renal cell carcinoma (RCC).

A preliminary review of the data showed that overall the median PFS for Inlyta exceeded the median PFS for sorafenib, but did not meet statistical significance. In a pre-specified subgroup of patients classified as good Performance Status (ECOG PS 0), the median PFS for Inlyta exceeded the median PFS for sorafenib. In another pre-specified subgroup of patients classified as intermediate Performance Status (ECOG PS 1), there was no difference between Inlyta and sorafenib.

Adverse events for Inlyta were generally consistent with previous findings in Inlyta patients with advanced RCC who had been treated with a prior systemic therapy.

These data will be further analysed and presented at an upcoming medical congress.

“We narrowly missed the primary endpoint in this trial,” said Dr Mace Rothenberg, senior vice president of clinical development and medical affairs for Pfizer's Oncology Business Unit. “We are analysing the study findings to determine whether further evaluation of Inlyta in specific sub-populations of treatment-naïve patients with advanced RCC would be warranted.”

AGILE 1051, a trial of more than 280 treatment-naïve patients with advanced RCC, was powered to show a 78 per cent improvement in PFS benefit with Inlyta over sorafenib. The primary endpoint of the study was PFS. The secondary endpoints of the study included overall survival, response rate and safety. Pre-specified subgroups were also analyzed and included patients with either good Performance Status (ECOG PS 0) or intermediate Performance Status (ECOG PS 1). ECOG performance status is a standard measure used to assess functional status of patients and these were stratification factors at randomization.

Earlier this year, Inlyta was approved for patients with previously treated advanced RCC in the US, EU, Japan, Switzerland, Canada, Korea, and Australia. In its registrational phase III AXIS trial, Inlyta significantly extended PFS with a median PFS of 6.7 months as compared to 4.7 months for those treated with sorafenib. The differences in PFS observed in the subgroups in the AXIS trial favoured Inlyta over sorafenib, including in the ECOG PS 0 and ECOG PS 1 subgroups.

“We set a high bar in our Inlyta trials to understand how it compares to another VEGF-targeted therapy,” said Dr Rothenberg. “Since approval, Inlyta has established its utility in the second-line setting where it is an important treatment option for many patients with advanced kidney cancer.”

Pfizer is also investigating axitinib in the AGILE 1046 study, a randomized phase II clinical trial in treatment-naïve patients with advanced RCC. Blinded efficacy data from this ongoing study were presented at ASCO earlier this year. Axitinib is also being studied in a randomized phase II clinical trial for the treatment of hepatocellular carcinoma (HCC), which is currently closed to enrollment. Additionally, under a collaborative development agreement between Pfizer and SFJ Pharma Ltd. II, SFJ is conducting a Phase 3 clinical trial in Asia studying axitinib for adjuvant treatment of patients at high risk of recurrent RCC following nephrectomy (kidney removal).

Inlyta is indicated for the treatment of advanced RCC after failure of one prior systemic therapy. Inlyta, a kinase inhibitor, is an oral therapy that is designed to inhibit tyrosine kinases, including vascular endothelial growth factor (VEGF) receptors 1, 2 and 3; these receptors can influence tumour growth, vascular angiogenesis and progression of cancer (the spread of tumours).