Animal health drugmaker Aratana Therapeutics Inc said its experimental appetite-stimulating drug was found effective in dogs in a pivotal study.
Aratana shares jumped 21 per cent in extended trading on Friday.
The study showed that an oral 3 mg/kg dose of the drug, AT-002, given daily for four days significantly increased appetite in dogs, compared with those on placebo.
The company said it plans to submit the results to the US Food and Drug Administration as it seeks marketing approval, and expects to start commercializing the drug in 2016.
The company's pipeline includes a string of experimental drugs for pets with serious medical illness such as cancer, viral diseases and allergies.
The Kansas City-based company's shares were trading at $16.25 after the bell.