The firm, which makes treatments for cancer pain and multiple sclerosis, said revenues for the six months to 31 March rose to £12.9 million, from £11.1m a year earlier.
Revenues were boosted by an increase in research and development fees charged to Japanese partner Otsuka, which has the exclusive rights to develop and market GW’s Sativex cancer pain treatment in the US.
The increase in revenues helped GW post a profit of £124,000 for the first half, compared with a loss of £3.2m a year ago.
GW also said it has raised £19.5m from its flotation on the Nasdaq exchange in the US last month, which chief executive Justin Gover said was a “significant corporate milestone” for the firm.
He added: “With Sativex advancing through phase three trials in the US for cancer pain, commercialisation continuing in Europe and other parts of the world, four new clinical trials commencing in a highly promising cannabinoid product pipeline, and a strong balance sheet, we are very excited about the next phase in our company’s evolution.”