As the industry's competition in the rare kidney disease IgA nephropathy (IgAN) heats up in the U.S., Roche’s Chugai Pharmaceutical is making an M&A play to advance a leading contender across the globe. 

With a deal to buy out Tokyo’s Renalys Pharma for 15 billion yen ($98 million) upfront—plus up to 16 billion yen ($104 million) in milestones—Chugai is picking up rights to IgAN medicine sparsentan in Japan, South Korea and Taiwan. 

Sparsentan, developed by Travere Therapeutics, is already approved by the U.S. FDA as a treatment for certain patients with IgAN. Early last year, Renalys picked up rights to the drug in several Asian nations in exchange for an undisclosed upfront payment and up to $120 million in milestones. Travere obtained a minority stake in Renalys as part of the deal. 

Now, Chugai is swooping in to take over sparsentan efforts in the countries covered by the Travere-Renalys licensing deal. The deal comes as Renalys nears a phase 3 data readout this quarter for an IgAN trial of the drug in Japan.

"Renalys was built to close Asia's drug lag with a simple promise: Patients should not have to wait years for proven therapies,” Renalys CEO BT Slingsby, M.D., Ph.D., said in a statement. “By advancing sparsentan in Japan, we proved that the model works. Partnering with Chugai now scales it—accelerating access across Japan and the region and setting a new standard for how innovative renal medicines reach patients." 

A progressive autoimmune disease, IgAN occurs when immunoglobulin A builds up in patients' kidneys, causing inflammation that makes it more difficult for the organs to function. Many patients eventually progress to kidney failure. Supportive care and symptom management alone usually don't slow progression, demonstrating the need for targeted therapies. 

Besides IgAN, sparsentan has gained momentum as a promising therapy for focal segmental glomerulosclerosis (FSGS). In the U.S., Travere is awaiting the FDA’s decision in the use, which could be a blockbuster opportunity in itself, according to analysts.

In Japan, Renalys has obtained regulatory alignment on registrational trial plans for FSGS and Alport syndrome, according to the company's Oct. 24 release. 

The M&A deal comes as Travere and other players in the IgAN space vie for dominance in the U.S. market. Travere’s drug, marketed as Filspari in the U.S., carries a full FDA approval to slow kidney function decline in adults with primary IgAN who are at risk of disease progression. 

Rival Novartis has several irons in the fire for IgAN. Fabhalta, the company's first medicine to gain an accelerated FDA approval in the disease, recently prevailed in a phase 3 trial, setting up plans for a full approval application.

In addition, Novartis has a second approved IgAN drug, Vanrafia, and another late-stage asset in the pipeline.  

Besides those two players, Calliditas Therapeutics’ Tarpeyo is also cleared to treat patients with IgAN who are at risk of disease progression.