New injectable immunotherapy treatment for rare form of triple negative breast cancer
People with triple negative breast cancer that has spread to other parts of the body may soon benefit from pembrolizumab in combination with chemotherapy.
Pembrolizumab is used with chemotherapy in adults with triple negative breast cancer whose tumours express PD-L1 with a combined positive score (CPS - the number of PD-L1 positive cells in relation to tumour cells) greater than or equal to 10 who have not had chemotherapy for metastatic disease and where surgery to remove the tumour is not possible.
Clinical trial evidence shows that, compared with paclitaxel, pembrolizumab combination increases how long people have before their cancer gets worse and how long they live.
NICE already recommends atezolizumab in combination with chemotherapy for untreated PD-L1-positive, locally advanced or metastatic, triple-negative breast cancer. The population covered by NICE’s appraisal of pembrolizumab in combination with chemotherapy covers some, but not all, of those who are eligible to have atezolizumab in combination with chemotherapy. This is because for atezolizumab, PD-L1 expression is measured using a slightly different method called immune cell staining (IC). Atezolizumab combination is recommended by NICE for people with IC equal to or greater than 1%. This means that some people who can’t have atezolizumab combination could be eligible for pembrolizumab combination.
Following consultation on the previous draft guidance the company proposed that the pembrolizumab combination should be restricted to people whose tumours express PD-L1 with a CPS greater than or equal to 10 and IC <1%. This means that atezolizumab combination is no longer a direct comparator, thereby removing a key barrier to its approval by NICE and making pembrolizumab combination an alternative treatment for people who cannot have atezolizumab combination.
NICE’s independent appraisal committee also agreed that the pembrolizumab combination meets the higher cost-effectiveness threshold for life-extending treatments for people with a short life expectancy.
Given by injection every 3 weeks, pembrolizumab (also called Keytruda and made by Merck Sharp and Dohme) is a type of immunotherapy that specifically targets triple negative breast cancer. It works by blocking the activity of a protein known as PD-L1 which is produced in larger amounts on cancerous cells than normal cells. By blocking PD-L1 it helps the person’s own immune cells to attack the cancer.
The company estimates that the pembrolizumab combination will now be available to around 100 people a year with triple negative breast cancer that has spread to other parts of the body.
NICE has made positive recommendations in all 11 of its completed appraisals of breast cancer medicines since March 2018. On completion of this appraisal that number will be 12. These are all now available for clinicians to use in the treatment of NHS patients.