Study confirms low testosterone in crizotinib patients

A new multinational study confirms the impact of the recently-approved lung cancer medication, crizotinib, on testosterone. The study was published online first in the April 12, 2013, issue of Cancer.

A previous study by the University of the Colorado Cancer Center reported the common side effect of low testosterone in men treated with crizotinib. The new Cancer study, led by Andrew J. Weickhardt, Division of Medical Oncology, department of medicine, at the University of Colorado Anschutz Medical Campus in Aurora, Colo., confirmed these findings in a study that included researchers in the United States, Hong Kong, Italy, and the United Kingdom.

Researchers found that, in 84% of men treated with crizotinib, testosterone levels were below the lower limit of normal. In addition, approximately 80% of the men had symptoms associated with low testosterone, such as sexual dysfunction or depression.

“We’re starting to see drugs being approved more quickly and based on the results from far smaller numbers of patients than ever before. That’s great….however, it also puts the onus on clinicians who then start using these drugs in day-to-day practice to recognize either subtle or later onset side effects that may have been missed during the initial testing,” said Ross Camidge, MD, PhD, senior author of the paper and director of the thoracic oncology clinical program at the University of Colorado Hospital.

The researchers found that testosterone levels fell because the proteins albumin and SHBG that bind testosterone in the blood and act as a storage depot for the hormone dropped rapidly with crizotinib.

When clinicians find low testosterone levels, testosterone therapy may alleviate these symptoms, the researchers wrote. “Symptoms of androgen deficiency and free or total/ free testosterone levels should be tracked in male patients on crizotinib with consideration of testosterone replacement as appropriate,” the researchers wrote.