US Regulators Approve Female Sexual Pain Drug with Boxed Warning

The US Food and Drug Administration (FDA) has approved a new drug manufactured by New Jersey-based Shionogi  that is indicated for the treatment of dyspareunia, a condition that causes some women to experience moderate to severe pain during sexual intercourse.

The condition, brought on by hormonal changes during menopause, leaves vaginal tissues thinner, drier and more fragile, FDA explained. Those changes result in pain, but Shionogi's drug Osphena (ospemifene) acts like estrogen to reverse these changes.

Victoria Kusiak, deputy director of the Office of Drug Evaluation III in FDA's Center for Drug Evaluation Research (CDER), explained in a statement that the condition is "among the problems most frequently reported by postmenopausal women." The condition is thought to affect approximately half of all women in the US at some point in their lives.

Black Box Warning, But With Relatively Low Risk

The drug was approved by FDA on 26 February 2013, and marks FDA's fifth approval of the calendar year. According to Shionogi, it is the "first and only oral treatment alternative to vaginal or oral steroidal estrogens," and its clinical trials demonstrated "significant improvements" in both the reduction in pain and physical improvements.

But while the 1,800-woman placebo-controlled trial showed "significant improvement" according to both FDA and Shionogi, the trial also uncovered some significant risks that have left the product with a so-called "boxed warning."

That warning, also called a Black Box warning, prominently indicates in the patient labeling that a product represents higher-than-usual risks to a patient, which they should be aware of before starting a regimen of the product.

Osphena's warning notes elevated risks of endometrial cancer and cardiovascular disorders, and in particular strokes and blood clots.

Approximately one in every thousand women taking Osphena will experience a thrombotic or hemorrhagic stroke, and 3 women per 2,000 are expected to experience deep vein thrombosis. While those risks are significant, FDA noted that they are "low risks in contrast to the increased risks of stroke and deep vein thrombosis seen with estrogen-alone therapy," which is the current standard of treatment.

Shionogi noted that " more commonly reported adverse reactions (greater than or equal to 1%) in patients treated with Osphena 60 mg compared to placebo were:

• hot flush (7.5 percent vs. 2.6 percent)
• vaginal discharge (3.8 percent vs. 0.3 percent)
• muscle spasms (3.2 percent vs. 0.9 percent)
• hyperhidrosis (1.6 percent vs. 0.6 percent)
• genital discharge (1.3 percent vs. 0.1 percent)