(WXYZ) — A new pill is giving some people with advanced breast cancer more time before their disease worsens. The treatment is guided by a blood test that can spot resistance before a scan does.
The Food and Drug Administration has approved a new daily pill called Etcamah, also known as camizestrant. It’s for a specific group of patients who have advanced breast cancer, meaning that the cancer has spread beyond the breast. The cancer also uses the hormone estrogen to grow, but it doesn’t have high levels of a protein called HER2.
Now, treatment can involve drugs that block estrogen. But sometimes, the cancer finds a way around that treatment because tumors can adapt. One way is through a change in a gene called ESR1, which can allow cancer cells to keep growing even when estrogen is blocked. And that’s where Etcamah comes in. It’s designed to target those resistant tumors. It’s taken with one of three existing medicines called CDK4/6 inhibitors.
But one of the things that makes this new treatment different is the newly authorized blood test — Guardant360 CDx. What it does is look for tiny pieces of tumor DNA in the bloodstream. That can reveal the ESR1 change before a scan shows the cancer growing. And that gives patients an earlier chance to change treatment.
The results were encouraging. In the clinical trial, patients who switched to Etcamah went about 16 months before their cancer worsened, compared with about nine months for those who stayed on their original treatment. So, that’s roughly seven extra months before the cancer worsened.
As for side effects, the prescribing information includes a boxed warning about the risk of irregular heart rhythm. There are also warnings about an abnormally slow heart rate and potential harm to an unborn baby.
Now, the FDA granted accelerated approval based on the drug providing more time before the cancer worsened, rather than proof that patients live longer. The drugmaker, AstraZeneca, still needs to conduct additional studies to confirm that the treatment provides a meaningful benefit.
