GSK, partner iTeos scrap development of lung cancer therapy

By Kamal Choudhury

May 13 (Reuters) - Britain's GSK GSK.L and drug developer iTeos Therapeutics ITOS.O said on Tuesday they have stopped developing an experimental lung cancer drug, belrestotug, after it failed to stop the disease from progressing in two studies.

The discontinued drug belongs to a class of treatments focused on the TIGIT receptor that has fallen out of favor in recent years after a spate of clinical setbacks due to low efficacy.

Similar drugs developed by Merck MRK.N, Roche ROG.S and BeiGene 688235.SS have failed clinical trials in recent months as they could not slow disease progression or improve overall patient survival.

Emily Field, an analyst at Barclays, noted that the TIGIT class is met with indifference by investors as "no one really cares" since it was already considered "dead".

Belrestotug, which was being tested in combination with GSK's dostarlimab for treating advanced non-small cell lung cancer (NSCLC), did not demonstrate sufficient efficacy, leading to the termination of the collaboration, the companies said.

"We are truly disappointed by the results," iTeos Chief Executive Officer Michel Detheux said.

The companies will now cease enrolling new patients in the ongoing late-stage lung cancer trial.

NSCLC is the most common type of lung cancer in the United States, accounting for about 87% of all cases, according to the American Cancer Society.

Current treatment options for advanced NSCLC patients include Merck's MRK.N Keytruda and AstraZeneca's AZN.L Tagrisso, which belong to different classes of drugs.

ITeos said it has initiated a targeted review of strategic alternatives to enhance shareholder value, while GSK said it would now focus on other cancer programs, including antibody-drug conjugates.

In afternoon trading, U.S.-listed shares of GSK fell 3%.

However, shares of iTeos climbed 19% after the company said its cash reserves of $624.3 million as of March 31, significantly exceeded its market capitalization of $264.9 million as of the last close.