WASHINGTON: Drugmaker Hutchmed Ltd said on Monday the US Food and Drug Administration has declined to approve its cancer drug which was tested mainly in China, citing the need for a multi-regional clinical trial.

In its so-called Complete Response Letter to the company, the US regulator said current data, based on two trials in China and one bridging study in the United States, does not support an approval in the US at this time.

A multi-regional clinical trial that includes subjects more representative of the US patient population and aligned to current US medical practices is required, the FDA wrote in the letter.

The decision is a setback for Hutchmed and raises concerns for some other Chinese drugmakers who have been seeking to bring their products to the US market at lower costs by conducting a single-country clinical trial.

The FDA has raised concerns over lack of population diversity in single-country trials, citing need for conducting studies applicable to the US population.

In March, the US regulator declined to approve Eli Lilly and partner Innovent Biologics Inc’s lung cancer drug that had been studied only in China.

There are at least 25 applications from China in drug development phases, planned to be submitted or already under review by the FDA, that are predominantly or solely based on trial data from China, the regulator had said in February.