Having announced top-line results earlier this year, Aveo Pharmaceuticals and Astellas Pharma have published the full data set from a late-stage trial which show that their kidney cancer treatment tivozanib has a more favourable safety and tolerability profile than Bayer's approved therapy Nexavar.

In January, initial data from TIVO-1 showed that tivozanib beat Nexavar (sorafenib) with a longer median progression-free survival (PFS) rate in both the overall study population as well as the large subgroup of treatment naive population. Aveo and Astellas also noted that tivozanib recorded the longest median PFS ever reported in a Phase III trial for the treatment-naive population (70% of patients) at 12.7 months.

The latest data, to be presented at next month's American Society of Clinical Oncology meeting in Chicago, highlighted the tolerability of the oral, once-daily, investigational tyrosine kinase inhibitor "as evidenced by a distinctively low rate of dose interruptions and reductions". A total of 517 patients were randomised to tivozanib (260) or Nexavar (257) and 18% of those on the Aveo/Astellas drug needed dosing interruptions due to side effects, compared with 35% on the Bayer treatment.

The rate of patients requiring dose reductions was 14% for tivozanib compared with 44% for Nexavar. Aveo and Astellas quoted Duke University's Daniel George as saying that “despite recent advances in the treatment of kidney cancer, patients are in need of new options which are effective and well-tolerated. He added that “the superior PFS and favourable tolerability demonstrated by tivozanib in TIVO-1 represents an important potential step forward".

The companies plan to file for US and European approval for tivozanib to treat renal cell carcinoma later this year.