Orphan drug specialist Amicus Therapeutics is paying Dimerix $30 million cash for U.S. rights to the phase 3 prospect DMX-200, establishing it as a challenger to Travere Therapeutics in a rare kidney disease.
New Jersey-based Amicus’ hunt for de-risked assets that could address a significant unmet medical need led it to Australia. Melbourne-based Dimerix began a phase 3 study of the CCR2 inhibitor DMX-200 in focal segmental glomerulosclerosis (FSGS) kidney disease in 2022.
The Australian biotech recently aligned with the FDA on the use of proteinuria as an appropriate primary endpoint for traditional approval. Dimerix reported interim results on the effect of DMX-200 on proteinuria last year. With enrollment well underway and another interim analysis coming up, data that could support filings for FDA approval is in sight.
As the program advances, Amicus could pay Dimerix up to $75 million in development and regulatory milestones. A further $35 million is tied to the first sale of the drug. Beyond that, Amicus has committed up to $410 million in sales milestones and $40 million tied to potential future indications.
The FDA is yet to approve a therapy specifically for FSGS. That could change soon. Travere filed for FDA approval of Filspari in the indication this March. Amicus’ willingness to bet on DMX-200 despite the potential of a rival that is near approval reflects a belief that there is room for multiple approaches in FSGS.
Jeffrey Castelli, chief development officer at Amicus, said on an earnings call Thursday that DMX-200 “is specifically targeting the inflammatory signaling in the damaged kidney.” Other molecules, in contrast, are focused on hemodynamics. Some patients will respond better to one drug than the other, Castelli said, and physicians will try to figure out which is the right approach for each individual.
“With DMX-200, there are ways you can look at how much the inflammatory component is driving things. Those are going to be the patients we're going to see respond best in the trials, and those are going to be the patients that I think doctors will want to focus on,” Castelli said.
ChemoCentryx, now part of Amgen, was developing a CCR2 inhibitor with Vifor Fresenius Medical Care Renal Pharma until a phase 2 flop scuttled the FSGS program in 2020. Castelli discussed the differences between DMX-200 and earlier candidates, contrasting attempts to directly inhibit MCP-1 binding to the downstream approach of Dimerix’s molecule.
“What happened with traditional binding inhibitors is MCP-1 couldn't dock. It actually led to a rebound effect where MCP-1 levels dramatically increase, which then would compete with the inhibitor and kind of lead to a muting effect,” Castelli said. “The beauty of the downstream blocking is that MCP-1 can still dock. That leads to MCP-1 degradation.”
Amicus believes the mechanism of DMX-200 will “really maximize the ability to shut down the monocyte inflammation,” Castelli said. The downstream effects will also allow “monocytes to continue their job elsewhere ... so they can still fight infections as they should outside of the kidney.”