After a high-profile rejection for Innovent Biologics’ Tyvyt, another China-made PD-1 inhibitor is starting a bid to win an FDA approval.

Elevar Therapeutics has filed to the FDA an application for a combination of Jiangsu Hengrui Pharma’s PD-1 inhibitor camrelizumab and VEGFR inhibitor rivoceranib, also known as apatinib, in newly diagnosed unresectable liver cancer, the company said Wednesday.

Both drugs have been approved in China, including in the first-line liver cancer indication in February. But neither are approved in the U.S.

If approved, Elevar and Hengrui will go after Roche’s PD-L1/VEGF pairing of Tecentriq and Avastin, which is currently the only FDA-approved immunotherapy for front-line liver cancer.

Elevar’s application is mainly based on data from the phase 3 CARES 310 study. The PD-1/TKI combo significantly slashed the risk of death by 38% over Bayer’s old standard Nexavar. Patients who took the combo lived a median 22.1 months, versus 15.2 months for the Nexavar group.

The filing faces a couple important challenges. First, for any combo therapy, the FDA requires proof of a meaningful contribution from each component. Given that neither camrelizumab nor rivoceranib are available in the U.S., no FDA-approved evidence exists to back their power.

But during an interview with Fierce Pharma back in October, then-Elevar Chief Medical Officer Jan Van Tornout pointed out the two drugs have single-agent data in advanced liver cancer in Chinese patients.

Another problem with CARES 310 is its high representation of Asian patients. The study enrolled 17.3% non-Asian patients, below the FDA’s desire of 20%, because of COVID disruptions, according to Van Tornout.

It’s a bold move for Elevar and Hengrui to target a relatively large cancer indication for a PD-1 inhibitor’s first approval in the U.S. Two other China-made PD-1s—tislelizumab by BeiGene and Novartis and toripalimab by Junshi and Coherus—are initially angling for niche indications and are both awaiting long-delayed FDA decisions.