FILE PHOTO: Signage is seen outside of the Food and Drug Administration (FDA) headquarters in White Oak, Maryland, U.S., August 29, 2020. REUTERS/Andrew Kelly/File Photo

By Kumar Tanishk and Sameer Manekar

(Reuters) -The U.S. Food and Drug Administration (FDA) sought more data from Telix Pharmaceuticals on its drug to detect a form of kidney cancer, the Australian cancer diagnostics firm said on Thursday.

Telix's Sydney-listed shares plunged as much as 24%, its worst intraday fall on record. It ended 18.8% lower at A$14.95 and was the weakest performer on the near-flat ASX 200 benchmark.

In December, Telix submitted an application to the FDA to approve its drug for kidney cancer imaging for commercial use.

The company said on Thursday that the FDA cited deficiencies and requested additional data to prove that the scaled-up commercial manufacturing process is comparable to the one used in clinical trials.

"Telix believes these concerns are readily addressable and submission remediation will begin immediately," the company said in an exchange filing.

The drug, branded Zircaix, would be used to help detect a specific type of kidney cancer known as clear cell renal cell carcinoma (ccRCC) via positron emission tomography (PET) scans.

Renal cell carcinoma affects more than 430,000 people worldwide, according to NIH data and ccRCC is the most common form of the disease. Two other types are chromophobe renal cell carcinoma and papillary renal cell carcinoma.

If the drug is approved, it would be the first PET scan-based drug specifically designed for kidney cancer in the United States and would enable easier and more accurate diagnosis without the need for invasive procedures.

Jun Bei Liu, portfolio manager at Ten Cap, said the regulator's concerns could materially impact any biotech's prospects in the U.S., a valuable market for healthcare firms.

"I don't think this delay changes long-term competitiveness, but if it turns out to be further issues with the manufacturing process, then it could be far more significant," Liu said.

(Reporting by Sameer Manekar, Kumar Tanishk, Padmanabhan Ananthan and Puyaan Singh in Bengaluru; Editing by Rashmi Aich and Harikrishnan Nair)