Helsinn Petition Seeks Block on Aloxi Copycat Product

Helsinn Healthcare has petitioned FDA to not approve a recently submitted 505(b)(2) NDA from Exela Pharma Sciences referencing Helsinn’s Aloxi (palonosetron hydrochloride) injection, indicated for preventing chemotherapy-induced nausea and vomiting. Submitted on behalf of the company by the law firm Hogan Lovells, the petition argues that the copycat version has a significantly different formulation than Aloxi and it raises safety and effectiveness issues.

In particular, the petition says, “Exela proposes to change the Aloxi formulation by more than doubling the drug concentration. Exela’s proposed high concentration would create a risk of confusion and medication error, particularly for pediatric patients who are dosed based on weight, where the volume of drug to be measured would be less than half of that with Aloxi.”

Helsinn contends that in similar situations, FDA previously has refused to approve products presenting new concentrations of known products due to confusion and medication error risks. “The agency should come to the same conclusion here,” it says. “In addition to the much higher concentration, the proposed Exela formulation does not have the same excipients as Aloxi. The proposed excipient changes affect key product characteristics, such as osmolality, associated with adverse events. Aloxi is formulated with an osmolality range that provides an isotonic solution. In patent certification notice letters to Helsinn, Exela has said that its product formulation ‘does not have an osmolality anywhere near [Aloxi’s] range’ and ‘is not isotonic. Exela’s formulation changes also may affect other key product characteristics, such as pH level and stability, that implicate potential safety issues and therefore require careful investigation.”

Moreover, the petition argues, Exela formulation changes have the potential to affect the product’s pharmacokinetics. If FDA considers approving the submission, Exela must bridge its proposed product to Aloxi with bioequivalence data because it seeks to rely on FDA’s finding of safety and effectiveness for Aloxi, it says, adding: “Because of formulation differences, there is no basis for FDA to presume that Exela’s product is bioequivalent to Aloxi, and in vivo data is therefore necessary.”