FDA gives go-ahead to first cancer drug based on genetics

The first cancer drug based on a specific genetic feature has been approved by the US drugs regulator.

The fast-tracked approval by the FDA marks a step forward in precision or personalised medicine, where therapy is based on individual genetics, rather than the facets of the disease such as location of the cancer.

'This is an important first for the cancer community,' said Dr Richard Pazdur, director of the FDA’s Oncology Center of Excellence. 'Until now, the FDA has approved cancer treatments based on where in the body the cancer started—for example, lung or breast cancers. We have now approved a drug based on a tumour's biomarker without regard to the tumour’s original location.'

Last week, the FDA, gave the go-ahead for Keytruda (pembrolizumab) to be used in the treatment of adult and child patients with solid tumours which have not responded to other therapies, or spread through the body.

The drug, made by pharmaceutical company Merck & Co based in New Jersey, targets tumours that contain a specific biomarker known as microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR).

Tumours with these markers have abnormalities which affect the repair of DNA inside the cell. Keytruda works by blocking a specific cellular pathway which cancer cells use to evade the body's immune system. By doing this, the drug may make the tumour more vulnerable to the body's own defences.

'It's exciting,' Dr Trever Bivona of the University of California, San Francisco told Nature News. 'It'll signal a very clear shift in the way the whole ecosystem operates: the FDA, the companies and the oncologists.'

Dr Drew Pardoll, director of the Johns Hopkins Bloomberg-Kimmel Institute that led the trial that was pivotal in Keytruda's approval, told Reuters that about four percent of advanced cancers, or 15,000 to 20,000 cases every year in the United States, carry the genetic trait for which the drug has just received approval.