Drug Development

Roche, Prothena hustle to PhII with their disease-modifying Parkinson’s drug targeting alpha-synuclein

Joseph Jankovic, Baylor

Prothena turned up at the big Alzheimer’s/Parkinson’s conference in Vienna over the weekend to detail early-stage data showing how its Roche-partnered drug PRX002/RG7935 can flush out toxic clusters of alpha-synuclein in Parkinson’s patients. And they used the occasion to note the launch of their Phase II study.

Investigators in the Phase Ib trial used multiple ascending doses of PRX002/RG7935 in Parkinson’s patients and found that a single dose could slash free serum alpha-synuclein levels by up to 97%, with the response maintained after two monthly doses.

That’s a snapshot of biomarker activity, which is certainly no guarantee of success in mid-stage trials. Companies like Roche have been trying, without success over the last 14 years, to modify Alzheimer’s by removing amyloid beta in the brain — which is a related strategy. But it’s what these two partners were looking for before moving into Phase II.

The drug is a standout in the field, which has been centered heavily on add-on drugs to the symptomatic therapy levodopa in reducing “OFF” times. Newron just obtained an approval for Xadago, which fits into the new class of symptomatic add-ons.

Roche and Prothena $PRTA will now launch the Phase II in the second quarter, looking for efficacy data for an antibody that targets alpha-synuclein, which some believe triggers Parkinson’s after it aggregates in the brain, causing pathological changes in healthy neurons.

“We showed a robust target engagement” with a dose dependent response, Baylor’s Joseph Jankovic, the primary investigator, told analysts on Sunday.

Roche inked a $600 million deal on this drug in 2013.

Prothena certainly isn’t alone in focusing on alpha-synuclein, and several of its rivals are also targeting Alzheimer’s. Switzerland’s AC Immune, partnered with Roche on AD, and Sweden’s BioArctic are focused on the same target, along with Prana and Proclara.


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