US approves breast cancer drug pair that delayed progression

Adults with a specific type of advanced breast cancer have a newly approved treatment option in the United States. On 18 September, the Food and Drug Administration granted full approval to Inluriyo plus Verzenio, a two-drug treatment that delayed cancer progression in a clinical trial.

The approval covers adults whose cancer worsened after at least one hormone treatment. Their tumours must be driven by oestrogen, lack high levels of the HER2 protein and carry an ESR1 gene mutation linked to hormone-treatment resistance. An FDA-authorised test must confirm the mutation.

In an exploratory analysis of 159 patients with the mutation in the Lilly-sponsored EMBER-3 trial, the median time before cancer worsened or death occurred was 11.1 months with the combination, compared with 5.5 months with Inluriyo alone. Whether patients live longer overall has not yet been established.

Both medicines are pills: Inluriyo blocks and breaks down oestrogen receptors that help some tumours grow, while Verzenio slows cancer-cell division.

The combination can cause serious side effects, including severe diarrhoea, low white blood cell counts, lung inflammation, liver problems and blood clots. Blood counts and liver function require regular monitoring. Lilly says the treatment is available immediately in the US.