(Reuters) - GlaxoSmithKline Plc GSK.L has agreed a deal worth more than $350 million (209 million pounds) with British biotech company Adaptimmune to develop cancer drugs based on novel cell-based therapies.

Adaptimmune said on Monday it would collaborate with GSK on its lead clinical program, which it said had already generated encouraging results in multiple myeloma, melanoma, sarcoma and ovarian cancer in trials in the United States.

The privately-owned company said it could receive payments in excess of $350 million over the next seven years from the tie-up, subject to development goals being met, and significant development and commercialization payments in subsequent years.

Adaptimmune said it would also receive sales royalties, ranging from single to double digits on net sales, on any products that reach market.

The company's cancer therapies work by re-engineering the patient's own t-cells, a type of white blood cell, to target and destroy cancerous or infected cells.

(Reporting by Aashika Jain in Bangalore and Paul Sandle in London; Editing by Eric Walsh and Kate Holton)