Shares in Incyte were trading up nearly 34% yesterday after posting promising mid-stage data for its pancreatic cancer therapy.

Top-line results from a Phase II trial showed that its JAK inhibitor Jakafi (ruxolitinib), in combination with Roche's Xeloda (capecitabine), improved survival in some patients with recurrent or treatment refractory advanced pancreatic cancer.

A pre-specified subgroup analysis in patients identified beforehand as most likely to benefit from JAK pathway inhibition showed that six-month survival in those given Jakafi was 42% versus 11% for placebo.

In addition, durable tumour responses were only observed in patients taking the drug, and it also achieved a significant improvement in body weight relative to placebo, the firm said.

On the safety side, the drug was generally well tolerated, with 12% of patients receiving the Jakafi regimen dropping out of the trial because of an adverse event compared with 20% who took Xeloda alone.

Data from the trial "provide the first evidence that JAK inhibition is active in this disease and suggest a demonstrable survival benefit in a well-defined group of patients with refractory metastatic pancreatic cancer who can be identified without the development of a companion diagnostic test," said Paul Friedman, Incyte’s President and Chief Executive.

Jakafi is already approved for the treatment of the blood cancer myelofibrosis, pulling in sales of around $136 million a year for Incyte. However, Wells Fargo & Co analyst Brian Abrahams believes that widening the drug's use could push its revenue up to $950 million in 2017, according to Bloomberg.

Novartis markets the drug outside US under the brand name Jakavi.