UPDATED: Endo finally wins a Low-T drug nod, but safety dispute could snarl its launch

Endo CEO Rajiv De Silva--FiercePharma file photo

For Endo's ($ENDP) testosterone therapy Aveed, the third time wasn't the charm with the FDA--but the fourth time was. After a trio of rejections, the FDA has given the thumbs up to the Low-T drug, and the Malvern, PA-based company expects to launch it this month. But amid the safety questions surrounding testosterone drugs, doing so may not be so easy.

Thursday, the FDA approved Aveed as an injection given once to begin therapy, once four weeks later, and every 10 weeks after that. The green light was welcome news for the company, whose regulatory setbacks spurred a $325 million cost-cutting drive and 700 layoffs last year.

"With Aveed, Endo can now offer men living with hypogonadism different treatment options to raise testosterone levels," CEO Rajiv De Silva said in a statement. "We are focused on getting Aveed to market to ensure that appropriate patients have access to it."

As Reuters notes, the FDA's most recent Aveed snub came last May, with the agency demanding a better plan from Endo to manage the drug's associated risks. The regulator focused on the risk of castor oil, part of the formulation, which has been linked to blood-vessel blockages in the lungs and other post-injection complications.

Activists, however, have focused not on the risks associated with castor oil, but on the risks associated with low-testosterone treatments in general. Public Citizen--the same consumer advocacy group that recently petitioned the FDA to add black box warnings to every testosterone drug sold in the U.S.--late last month asked the agency to stall its approval decision on Endo's drug, and Thursday it sent a letter to FDA Comissioner Margaret Hamburg urging her to reverse Aveed's go-ahead.

"I am writing to strongly protest and urge that you reverse the FDA's decision, announced by Endo this morning, to approve a very long-acting injectable form of testosterone (Aveed), because it will likely greatly expand the use of testosterone, now found to increase the risk of heart attacks and other cardiovascular diseases," Public Citizen founder Sidney Wolfe wrote in the letter.

So far, the FDA says it hasn't drawn any conclusions on whether testosterone treatments increase the risk of stroke, heart attack or death, as activists allege, though it did this year agree to reassess the issue after two years of monitoring. During that time, a marketing blitz has sent sales of testosterone products soaring, with critics blaming advertising for steering men toward using the drugs as lifestyle treatments.

But recent studies have turned up results that could spell trouble for Endo and other testosterone treatment-makers, such as AbbVie ($ABBV) and Eli Lilly ($LLY). Last November, a study published in the Journal of the American Medical Association found that using testosterone increased the risk of death from heart attack or stroke by 29% in men with or without a history of heart disease. And last month, the FDA said a separate study had found an increased risk of death among men with preexisting heart disease, regardless of age.

- read the release
- get more from Reuters
see Public Citizen's letter

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Editor's note: This story has been updated to include a letter from Public Citizen.