UK drug developer Adaptimmune slip after IPO prices at high end of expectations, raising $191M

Shares of cancer drug developer Adaptimmune are up slightly after the British company's initial public offering raised $191.3 million.

Adaptimmune sold 11.3 million U.S.-traded shares, more than it originally expected. The shares priced at $17 each, at the high end of Adaptimmune's expectations.

The stock advanced as much as 15 percent in morning trading before turning lower. They were trading at $16.69 in late morning trading Wednesday, down 31 cents.

Adaptimmune Therapeutics PLC is developing immune therapies designed to target and destroy cancer cells. The company is running several clinical trials of a drug called NY-ESO TCR through a partnership with GlaxoSmithKline PLC. Adaptimmune could get $350 million in payments through 2021, and additional payments based on development and sales.

The shares are trading on the Nasdaq Global Market under the symbol "ADAP."