USFDA rejects Amneal Pharma Parkinson's drug over safety concerns

The health regulator, in a complete response letter, has requested additional data as it was not convinced beyond doubt about the safety of one of the ingredient, carbidopa, used in the drug, even though some studies have demonstrated the safety of the other component, levodopa, the company said.

The agency has not identified efficacy or manufacturing issues with the treatment.

The drug is a new formulation of carbidopa-levodopa, the standard of care for Parkinson's, and is designed to allow it to remain in the small intestine for a longer period, helping in its consistent absorption.

The company said it would work with the FDA to address the issues.

The complete response letter comes as a surprise, said Barclays analyst Balaji Prasad. The decision will likely delay a launch to until at least the first half of 2024, he added.

Amneal has been looking to rake in more than $500 million in revenues from its specialty business by 2027.

The decision does not impact 2023 forecast as it did not include the revenue from the drug, the company said.

Amneal has another Parkinson's drug, Rytary, on the market but has been struggling to gain a foothold in the treatment space. Only 4% of patients use the drug since its approval in 2015, as per company estimates.

Parkinson's is a brain disorder that causes unintended or uncontrollable movements and is the second most-deadly neurodegenerative disease after Alzheimer's.

There is no cure currently, but medicines and other therapies can help relieve symptoms.