UPDATE 1-XenoPort posts narrower-than-expected Q1 loss

* Q1 loss/shr $0.10 vs estimates of $0.31

* Q1 loss narrower on higher collaboration rev

May 5 (Reuters) - Biopharmaceutical company XenoPort Inc (XNPT.O) posted a narrower-than-expected quarterly loss, helped by higher milestone revenue from one of its products.

For the first quarter, the company posted a net loss of $2.7 million, or 10 cents a share, compared with a net loss of $7.3 million, or 29 cents a share, a year ago.

Revenue increased to $26.3 million from milestone payments on submission for marketing approval of its experimental drug to treat restless legs syndrome, XP13512, or Solzira.

Analysts, on an average, were expecting a loss of 31 cents, excluding items, on revenue of $20.4 million, according to Reuters Estimates.

XenoPort has licensed rights to develop and commercialize Solzira to Astellas Pharma Inc (4503.T) in Japan and five Asian countries and to GlaxoSmithKline (GSK.L) in all other regions of the world.

Shares of the Santa Clara, California-based company closed at $14.78 Tuesday on Nasdaq. (Reporting by Vidya L Nathan in Bangalore; Editing by Jarshad Kakkrakandy)