GTx Inc., FDA to Begin Trials on Cancer Drug

By Aisling Maki

GTx Inc., a Memphis-based pharmaceutical company, has announced an agreement with the U.S. Food and Drug Administration to begin Phase III clinical trials to evaluate Ostarine, a drug designed to prevent and treat muscle wasting in cancer patients.

McDavid Stillwell, GTx director of corporate communications, said the FDA and GTx worked together for about six months to arrive at an agreement for the Phase III clinical development program.

“Going into that period, there were a number of things that were uncertain that now are certain and that are exciting,” Stillwell said. “We at first weren’t able to tell investors whether we’d be going into Phase III studies or whether there was more Phase II work to be done. The FDA made it clear to us that this asset is ready for Phase III registration clinical studies.”

GTx will initiate the Ostarine Power1 and Power2 Phase III clinical trials in July, with an expected completion date in the fourth quarter of 2012.

Also in July, the company plans to initiate Ostarine Phase III international clinical trials – placebo-controlled, double-blind clinical trials involving 300 patients with late stage non-small cell lung cancer entering their first line of chemotherapy.

Stillwell said about half of the study sites will be in the U.S., while the other half will be in Europe and South America.

Patients will be administered either placebo or three milligrams of Ostarine, and the effects of the drug on lean body mass will be determined by measuring bone mineral density and assessing physical function at three-month and five-month endpoints.

Stillwell said GTx, whose office is Downtown at 175 Toyota Plaza, at first didn’t know what duration of trials the FDA would require initially thinking the study duration would be 12 months.

However, the FDA said that because patients had median life expectancies of eight to 11 months, a 12-month study would leave them with too much missing data, and the administration decided on five-month study duration with a three-month endpoint.

GTx stock shares have continued to rise – double the price in March – since the company announced Ostarine had taken a step moving it closer to market.

“The company has had a number of things happen over the last six months that have been exciting, and the first is that our Ostarine clinical development program has been given direction – and that’s substantial,” Stillwell said.

“Investors now know that this program is moving forward for an important indication, and they also understand that these are timelines that are close. Under our timelines, the last patient’s last visit for both studies will be at the end of 2012. In the biotech industry, that’s a near-term event, so, suddenly this program becomes one that has the potential to get on the market soon.”

Stillwell said three studies now have shown that Ostarine treatment results in increased muscle mass and improvements in physical function for patients with non-small cell lung cancer.

Muscle wasting is a common cancer-related problem resulting in decline in physical function, and limitations in physical function predict the ability of a non-small cell lung cancer patient to tolerate chemotherapy.

Patients with functional limitations are less likely to be administered treatment, and functional status is also a predictor of survival.

About half of patients with advanced non-small cell lung cancer suffer severe muscle loss, and muscle weakness and functional limitations are highly prevalent, with 88 percent of patients reporting difficulty climbing stairs, lifting and carrying small loads, walking short distances and stopping, crouching or kneeling.

Muscle wasting and weakness are also side effects of many chemotherapy drugs, and there are presently no drugs approved for the prevention and treatment of muscle wasting in cancer patients.

“Muscle wasting, which is so common in lung cancer patients, along with the associated weakness and fatigue, can result in diminished quality of life, loss of independence, and decreased ability to tolerate and benefit from cancer treatment,” Dr. Jeffrey Crawford, chief of Medical Oncology at Duke University Medical Center and lead investigator of the Power clinical trials, said in a statement. “A medical intervention which helps non-small cell lung cancer patients stay strong would be an important addition to the treatment armamentarium.”

Stillwell said the hope is that Ostarine treatment can begin as soon as patients are diagnosed, at the same time first-line chemo is initiated, to delay the loss of muscle mass and make patients stronger.