The U.S. Food & Drug Administration declined to approve two China-tested cancer treatments on Monday, raising concerns over the future of drugs tested in single-country trials.

The decisions could add pressure on Chinese stocks, especially biotech companies, at a time shares of several U.S.-listed Chinese companies have been falling on the potential risk of being de-listed.

The FDA sent a so-called Complete Response Letter to Hutchmed Ltd  stating its treatment for neuroendocrine tumors requires data from a trial that is more representative of the U.S. patient population.

Separately, the FDA also declined to approve Coherus BioSciences Inc  and Chinese partner Shanghai Junshi Biosciences Co Ltd’s cancer drug to treat a type of nasopharyngeal carcinoma, citing the need for quality process changes.

However, Coherus said the FDA indicated existing data on the drug, toripalimab, supports a re-submission of the application.

Coherus’ Chief Executive Officer Denny Lanfear said:

The FDA has stated this indication warrants regulatory flexibility with respect to the sufficiency of single-country clinical data.

Coherus and Shanghai Junshi plan to meet with the FDA and re-submit their application for the drug’s approval by mid-summer 2022, the companies said.

The regulator also cited issues concerning inspection of facilities for both the treatments due to delayed travel during the COVID-19 pandemic.

It has raised concerns over lack of population diversity in single-country trials, citing the need for conducting studies applicable to the U.S. population.

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 said in February.