Knight gains rights to IPX203, for off times, in Canada and Latin America

Extended-release carbidopa/levodopa combo showed benefits in Phase 3 trial

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by Andrea Lobo |

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Knight Therapeutics has entered into an exclusive license agreement with Amneal Pharmaceuticals giving it rights to apply for  regulatory approval of IPX203 in Canada and across Latin America, and, if granted, to market the Parkinson’s disease treatment there.

IPX203 is an investigational, extended-release oral formulation of carbidopa/levodopa, intended to ease Parkinson’s motor symptoms.

“We have found in Knight an equally committed partner who will work with us to advance IPX203 and bring it to patients across Canada and Latin America,” Chirag and Chintu Patel, Amneal’s co-CEOs, said in a company press release. “We see IPX203 as a critical innovation that can meaningfully advance the standard of care for Parkinson’s patients.”

Financial terms of the agreement were not disclosed.

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IPX203 aims for sustained motor control, less frequent levodopa doses

Parkinson’s is caused by the progressive loss of nerve cells that produce dopamine, a major signaling molecule involved in the control of voluntary movements. Carbidopa/levodopa combination is a mainstay disease treatment, working to increase dopamine levels in the brain and ease motor symptoms.

Levodopa is a precursor of dopamine that can enter the brain, where it is used to produce dopamine; carbidopa works to prevent levodopa from being converted into dopamine before it reaches the brain. Various carbidopa/levodopa treatments are available, but the prolonged levodopa use is tied to off episodes, periods when treatment effects wear off between doses and dyskinesia (involuntary movements) and other motor symptoms return.

IPX203 is a new capsule formulation of extended-release carbidopa/levodopa, designed to maintain steady levels of the molecules in the body and improve absorption. It contains immediate-release granules of carbidopa and levodopa, as well as extended-release beads of levodopa alone.

The therapy was evaluated in the Phase 3 RISE-PD trial (NCT03670953) that enrolled 506 people with advanced Parkinson’s and motor fluctuations at sites in the U.S. and Europe. Patients were randomized to 13 weeks of treatment with IPX203 or a generic immediate-release carbidopa/levodopa formulation.

Results showed that IPX203 was better at prolonging daily on periods — times when motor symptoms are controlled — and reducing off periods than the immediate-release therapy.

These benefits were achieved with fewer daily doses: an average of three doses with IPX203 and an average of five doses with the immediate-release formulation. Trial results also were published last year.

FDA requested more safety data for carbidopa in Amneal’s formulation

A nine-month and open-label extension study that followed in 419 of these patients, (NCT03877510), found that IPX203 remained safe and effective in controlling motor fluctuations over time, with a stable mean of three daily doses.

“There is a high unmet medical need in the treatment of Parkinson’s disease and we are confident that, with IPX203, we will be bringing a much needed novel treatment option to Parkinson’s patients,” said Samira Sakhia, Knight’s president and CEO.

Amneal applied to the U.S. Food and Drug Administration (FDA) for IPX203’s approval in August 2022. But in a complete response letter issued in July 2023, the FDA asked for more safety information before making a final decision.

Specifically, the agency found sufficient evidence to support the safety of levodopa in the formulation, but not in establishing the safety of carbidopa. No questions were raised regarding IPX203’s effectiveness or production.