Tesaro shares jumped nearly 15 percent to $27.51 in premarket trading, after the company said the drug, rolapitant, achieved statistical significance over standard therapy in 532 cancer patients.
The most frequently observed adverse events in both groups included fatigue, constipation and loss of appetite, the drug developer said on Monday.
In December Tesaro had said rolapitant, one of its lead compounds, was also found to be effective for chemotherapy-induced nausea and vomiting (CINV) in two other late-stage trials.
Tesaro’s stock, however, had fallen then as rolapitant failed to show enough benefit to give it an edge over competing drugs like Merck & Co Inc’s Emend.
Emend is approved to treat CINV and can help prevent it for up to five days from when chemotherapy starts.
Rolapitant and Emend belong to the same class of drugs known as NK-1 receptor antagonists, which work by blocking a substance in the brain that stimulates vomiting reflex.
Over 70 percent of patients undergoing chemotherapy suffer from nausea and vomiting that may result in a delay or discontinuation of treatment. Prolonged nausea and vomiting can also lead to weight loss, dehydration and malnutrition.
Waltham, Massachusetts-based Tesaro acquired the development and marketing rights to rolapitant from Opko Health Inc in December 2010 for up to $121 million, including up-front and milestone payments.