GTx developed a chemical that acts like testosterone but is specific for muscle growth, so it doesn't trigger the side effects. In an early trial, 159 people with various cancers received the drug, enobosarm, or a placebo in addition to their normal cancer treatment. Those who took enobosarm for four months held on to their muscle and even gained a few pounds — the equivalent of a "50-ounce steak," Steiner says. They were also better at climbing a dozen stairs. For the average-sized person, the improvement would be akin to toting an extra 13 pounds up the steps, he says. GTx presented the results at cancer meetings in 2009 and 2010.
GTx is now testing enobosarm in two trials, each involving 300 patients with non-small cell lung cancer, the most common type of lung cancer. Lung cancer is the biggest cancer killer and frequently comes with severe cachexia. Steiner expects results in 2013 and, if all goes well, predicts the drug could be available at the beginning of 2014. He envisions enobosarm being prescribed not only to treat cachexia but also to prevent or delay the wasting.
GTx's approach is exciting, says Del Fabbro of M.D. Anderson, as is that taken by Helsinn. That company's drug, anamorelin, is designed to mimic the effects of the "hunger hormone" ghrelin, which boosts appetite, builds muscle, pushes food through the digestive system and cuts inflammation.
More than 300 people with cancer have taken anamorelin for up to three months, says Dr. John Friend, a family medicine physician and senior vice president for research and development at Helsinn. They gained weight and reported improved quality of life on questionnaires. Helsinn reported early trial results at an oncology meeting in 2007.
Helsinn is now enrolling about 950 people in two trials, which Friend expects to complete in 2013. With good results, he hopes Helsinn could release the drug in 2015 or 2016.
If they are successful with non-small cell lung cancer, Helsinn and GTx are interested in expanding their drugs to other cancers and cachexia conditions.
The most exciting approach to cachexia is to interfere with the biological systems directly causing it, Natale says. For example, natural body chemicals called myostatin and activin normally prevent muscle buildup. Some researchers hope to treat muscle loss with drugs that sponge up myostatin or activin.
As reported in a 2010 study in the journal Cell, scientists from Amgen Research in Thousand Oaks reversed muscle wasting in cancer-ridden mice using a medicine that sticks to activin, preventing it from acting on muscle. Harvard's Goldberg, who worked on the study, was excited to see that not only did the treatment reverse the low appetite and weight loss but also "the animals lived much longer, despite having an enormous tumor," he says. (Amgen declined to comment on any further work.)
It's too early to say whether people, like the mice, would live longer if their cachexia were controlled with medication. Gralla would be happy if the drugs just make the time they have more enjoyable; increasing survival would be a "bonus," he says.