UPDATE 2-Xenoport payments delayed by NDA withdrawal

(Adds details, analysts' comments, updates share movement)

BANGALORE, Nov 10 (Reuters) - XenoPort Inc (XNPT.O) said about $23 million in milestone payments from its partners would be delayed, after the new drug application for a drug to treat restless legs syndrome was withdrawn, sending its shares down to a new 52-week low.

XenoPort is developing Solzira, its lead product candidate, in partnership with GlaxoSmithKline (GSK.L) and Astellas Pharma (4503.T).

Glaxo and XenoPort said they would resubmit the new drug application for the drug after U.S Food and Drug Administration (FDA) requested the data in a single study to be reformatted.

"In our view, the decision to withdraw and resubmit the Solzira's NDA is appropriate, likely to maintain in good terms the relationship with the FDA and the fastest alternative," Ladenburg Thalmann and Co analyst Juan Sanchez said.

Reformatting of the dataset does not change the outcome of the endpoint and management was clear that the NDA withdrawal does not relate to the content of the filing, he said.

Glaxo will also conduct a review of other trial data sets taking the U.S. health regulators' input into account and plans to resubmit the NDA once this work is complete.

"Our best guess is the NDA is refilled by the end of first-quarter of 2009, based on the standard 4-6 month industry timeframe for writing an entire NDA," Cowen and Co analyst Rachel McMinn said. She has an "outperform" rating on the stock.

Ladenburg Thalmann's Sanchez maintained a "buy" rating on the stock but cut the price target to $50 from $55 as he delayed Solzira's related cash flows in his model by 5 months.

Under the deal, Astellas Pharma holds the development and marketing rights of Solzira in Japan and five Asian countries, while Glaxo has the rights for the rest of the world.

Shares of XenoPort were trading down about 13 percent at $34.54 in afternoon trade on Nasdaq. They had earlier touched a low of $30.10. (Reporting by Aradhana Aravindan and Esha Dey in Bangalore; Editing by Pratish Narayanan, Anil D'Silva)