The National Institute for Health and Care Excellence issued draft guidelines turning down Amgen’s Imlygic as an option for people with melanoma that has spread and can’t be surgically removed, because of uncertainty over its effect on survival compared with other treatments.

The therapy, which is also known as T-Vec (talimogene laherparepvec), is a modified form of the herpes simplex virus type-1 approved by European regulators last year as the first oncolytic immunotherapy to treat adults with unresectable melanoma that is regionally or distantly metastatic with no bone, brain, lung or other visceral disease.

Imlygic is injected directly into tumour tissue and then replicates until the membrane of the cancer cells rupture, thereby destroying them. The virus contained in these cells is then released locally in the tumour tissue along with granulocyte-macrophage colony-stimulating factor (GM-CSF), a white blood cell growth factor that the virus is engineered to express, which kill tumour cells throughout the body.

Data from one clinical trial showed a 50% or greater reduction in size in 64% of injected tumours, one-third of uninjected non-visceral tumours, and 15% of visceral tumours were also reduced by at least 50%. Also, there were 35 melanoma-related surgeries performed during this trial of which 30% successfully removed all residual disease.

While melanoma is curable when detected in the early stages, metastatic melanoma continues to be one of the most difficult-to-treat cancers because it is highly aggressive and complex. Even with recent new options in immune-oncology, a large number of patients still fail to respond to treatment, highlighting the remaining unmet need.

Carole Longson, director of the Centre for Health Technology Evaluation at NICE, noted that Imlygic represents an innovative approach to treating the disease, and that the committee heard from the patient and clinical experts that because it has fewer side effects than other drugs for advanced melanoma, it would be particularly valuable to some people with this condition. 

“However, the committee concluded that there was not enough evidence to be able to say whether talimogene laherparepvec is as clinically effective as other drugs used to treat advanced melanoma,” she said. “Given the uncertainty about its effect on overall survival compared with these drugs it was not possible to recommend talimogene laherparepvec as a cost-effective use of NHS resources.”