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July 22 (Reuters) - Puma Biotechnology Inc said its experimental breast cancer drug met its main goal in a late-stage trial.
Shares of the company, which doesn't have any drug in the market, tripled to $176.94 in extended trading.
Puma said on Tuesday it plans to file for marketing approval of neratinib, codenamed PB272, in the first half of 2015.
Adjuvant treatment with the drug showed a statistically significant improvement in disease-free survival of 33 percent versus patients on placebo, according to trial data.
Adjuvant treatment, or additional treatment, is given after the primary treatment.
Patients in the trial were treated with neratinib after adjuvant treatment with cancer drug trastuzumab in women with early-stage HER2-positive breast cancer.
Cancer cells with above-normal levels of the HER2 protein increases breast cancer risks.
Breast cancer is the leading cause of cancer deaths among women worldwide, with about one million new cases reported each year.
Neratinib, licensed from Pfizer Inc, is also being studied in patients with non-small cell lung cancer and other solid tumors that have a HER2 mutation.
Puma also said it has amended its licensing agreement with Pfizer under which it will have to pay the larger drugmaker annual royalties on net sales of neratinib at a fixed rate in low- to mid-teen percentage rate.
Puma was obligated to pay Pfizer incremental annual royalties between 10 and 20 percent of net sales of neratinib, under the original agreement.
Under the amended agreement, Puma will be solely responsible for ongoing clinical trials expenses.
Puma said it expects research and development expenses to increase by about $30 million.
(Reporting by Shailesh Kuber in Bangalore; Editing by Joyjeet Das)