FDA panel to weigh up GSK, Merck sarcoma drugs tomorrow

GlaxoSmithKline and Merck & Co are both hoping to persuade an FDA advisory committee tomorrow that their sarcoma drugs are worthy of approval, despite limited effects on survival.

GSK's angiogenesis inhibitor Votrient (pazopanib) will be first up before the Oncologic Drugs Advisory Committee (ODAC) tomorrow, with the panel considering the firm's application to market the drug for advanced soft tissue sarcoma in patients who have already received chemotherapy.

Thereafter, they will consider Merck's application for mTOR inhibitor Taltorvic (ridaforolimus) in patients with metastatic soft tissue sarcoma or bone sarcoma who have completed at least four cycles of prior chemotherapy.

FDA reviewers posted their own appraisals of the two applications on Friday, noting that in a clinical trial Votrient achieved progression-free survival (PFS) of 4.6 months versus 1.6 months for placebo, although it provided no improvement in overall survival and had significant side effects that have led to therapy discontinuation or death.

Meanwhile, the reviewers said data submitted by Merck in support of Taltorvic found that patients receiving the drug had a median PFS of 17.7 weeks, versus 14.6 weeks for placebo), with no effect on overall survival. The FDA said its own analyses had concluded that the increase in PFS was just two weeks (16.1 weeks versus 14.0 weeks, and had to be considered in the context of the drug's safety profile.

Around 14 per cent of patients discontinuing therapy due to side effects including kidney failure, infections and lung complications, compared to 2 per cent of patients on placebo.

The National Cancer Institute estimates about 11,000 Americans were diagnosed with soft tissue sarcoma in 2011, and about 4,000 died from the disease. The median survival time for patients diagnosed with advanced or metastatic disease is typically around 12 months.

Votrient is already approved in the US to treat renal cell carcinoma - bringing in £100m ($160m) in this indication last year - and is also in phase III testing for ovarian cancer. Analysts have suggested the drug could achieve turnover of more than $500m at peak. Meanwhile, Taltorvic has been predicted to make around $300m a year if approved.