The good news:
The FDA approved Imjudo® (tremelimumab) plus Imfinzi® (durvalumab) and chemotherapy based upon the Poseidon trial, which showed that 4 cycles of Imjudo/Imfinzi/chemotherapy significantly improved overall survival compared with 6 cycles of chemotherapy alone. A median overall survival of 14 months was reported in the combined treatment group and 11.7 months in the chemotherapy alone group. Overall response rates, progression-free survival and duration of response were also higher with Imjudo/Imfinzi/chemotherapy compared to chemotherapy alone.
Why it’s significant:
Imjudo and Imfinzi are immune checkpoint inhibitors – drugs which boost the immune system by different mechanisms. Unlike in other chemotherapy/immunotherapy trials, the survival benefit was seen regardless of how much PD-L1 was in the tumor, although patients whose tumors had more than 50% PD-L1 benefited the most.
The advantage of this regimen over others:
This study shows that Imjudo, which boosts the immune system by blocking a protein called CTLA4, is active against this disease. (Most other immunotherapies used in lung cancer block either PDL or PD-L1.)
So, what’s the rub?
The results of the Poseidon trial are similar to other studies which compared one or two immunotherapies plus two chemotherapies, so experts have called this a “me too” regimen. In addition, four-drug regimens cost more than a three-drug regimen, and have more side effects. This represents another treatment option but not necessarily a better one.