Puma Biotechnology said its experimental breast cancer drug met its main goal in a late-stage trial, but the options market is smelling something "fishy."
Shares of the company, which doesn't have any drug in the market, spiked nearly 300 percent on Wednesday. (Click here to see how Puma shares are trading).
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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.
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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.
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Meanwhile, someone seems to have bet big in the options market that Puma would be a winner in the days before the positive results.
Whether the trading on July 15 is suspicious or not, the report showing a Puma drug's success against breast cancer in a late stage study clearly surprised some Wall Street analysts. Stifel reportedly had predicted a "grim" outlook for neratinib, and Cowen said the report showed surprisingly positive data.
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Neratinib, licensed from Pfizer, is also being studied in patients with non-small cell lung cancer and other solid tumors that have a HER2 mutation.
"It could be a biotech fund taking that big shot. The timing's great though," said OptionsMonster co-founder Jon Najarian, who pointed out options activity and called it "fishy." The stock was trading at $216 at mid-morning Wednesday, up 159 points or 242 percent.
The U.S. Securities and Exchange Commission declined to provide comment to CNBC on the options activity.
Puma did not respond to CNBC's request for comment.
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.
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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.
— By Reuters. CNBC.com contributed to this report.