Aug 28 (Reuters) - The U.S. Food and Drug Administration

(FDA) sought more data from Telix Pharmaceuticals ( TLX ) 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.