FDA Rejects Testosterone Autoinjector Xyosted

Marlene Busko

October 23, 2017

The US Food and Drug Administration (FDA) has declined to approve a new drug application (NDA) for testosterone enanthate (Xyosted, Antares Pharma) in a proprietary autoinjector and has raised two clinical concerns.

Antares Pharma had applied for approval of the product for men with physician-determined hypogonadism. The prefilled, single-use injector enables patients to self-administer testosterone at home instead of applying a patch or gel or having an intramuscular injection in a doctor's office.

The FDA identified two safety concerns, said the company in a statement: first, that Xyosted could cause a clinically meaningful increase in blood pressure; and second, it is concerned about the occurrence of depression and suicidality.

The next step will be to request a meeting with the FDA to further evaluate the deficiencies raised and agree upon a path forward for potential approval, the company said.

"We are disappointed with the outcome of the review and are assessing the content of the complete response letter, including the information that may be needed to resolve the deficiencies,” noted Robert F Apple, president and chief executive officer of Antares Pharma.

"The company remains committed to bringing Xyosted to market and will work closely with the FDA to determine the appropriate responses to the deficiencies noted in the letter,” he added.

The complete response letter did not cite any chemistry, manufacturing and controls, device, or efficacy issues.

STEADY Testosterone Levels, but Serious Adverse Events Concern FDA

In 2015, the FDA asked Antares Pharma for additional safety data after a patient developed hives in a midstage trial. The company eventually submitted the NDA for review in December last year under the product name QuickShot Testosterone, which was renamed Xyosted.

First-line results from the phase 3 Subcutaneous Testosterone Enanthate Safety in Adult Men Diagnosed With Hypogonadism (STEADY) trial, presented at ENDO 2017: The Endocrine Society Annual Meeting in April and American Urological Association (AUA) 2017 Annual Meeting in May, showed that men using Xyosted attained steady testosterone levels in the blood, the company says.

The proprietary autoinjector, the company notes, is "designed to allow rapid subcutaneous self-administration of highly viscous drugs such as testosterone and biologics using high spring pressure through a fine-gauge needle" and "can also provide the patient with the ease and speed of self-administration, comfort, and discretion," according to the company.

The most common adverse reactions that occurred in 5% or more of patients were increased hematocrit, hypertension, increased prostate-specific antigen, upper respiratory tract infection, sinusitis, injection-site bruising, and headache.

Reported serious adverse events included one case each of worsening depression, vertigo, and suicide that were not considered related to the study drug, although the suicide could not be ruled out as potentially related.

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