NEW YORK (

TheStreet

) --

XenoPort

(XNPT)

was the biggest gainer among small-caps Thursday after the biotech company won approval for its first drug Horizant used to treat moderate-to-severe restless leg syndrome. The stock was up 66% at $10.64 on volumes of more than 17 million shares.

Shares of

Immunogen

(IMGN) - Get Report

jumped 21% to $11.28 after an experimental breast cancer drug that it is developing with

Roche

was found to be more successful than the standard treatment in a mid-stage study.

Retail stocks were buzzing after stronger-than-expected same-store sales data.

Pier 1 Imports

(PIR) - Get Report

saw its shares climb 9% to $11.52 after it reported better-than-expected results. Sales rose 7.7% to $426.6 million, beating the analysts' average estimate of $425.6 million. Sales at stores open at least a year rose 8.9%.

Rite Aid

(RAD) - Get Report

was up 6.6% to $1.13 after it posted a narrower-than-expected loss and its sales stabilized. The company said it may narrow its losses significantly in fiscal 2012, and forecasted stronger revenue than analysts expected.

Express

(EXPR) - Get Report

shares were climbing 4.5% to $20.23. The company announced the pricing of the offering of 19,800,000 common shares by certain stockholders at $19 a share, reflecting an upsize from the previously announced offering of 16.5 million shares.

Shares of

Intersil

(ISIL)

rose rising 5.8% to $14.09.

Stocks of semiconductor companies were climbing after

Texas instruments (TXN) - Get Report

said earlier this week it will acquire

National Semiconductor

(NSM)

for $6.5 billion.

Shares of

Rare Element Resources

(REE)

and

Avalon Rare Metals

(AVL)

were soaring 10.7% and 4.9%, respectively. A bill was introduced Wednesday that would benefit U.S. rare earth miners, according to a

release from the U.S. Magnetic Materials Association.

--Written by Shanthi Bharatwaj in New York

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Shanthi Bharatwaj

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