Checkpoint inhibitors continue to show signs of hope in the treatment of patients with non-small cell lung cancer (NSCLC), yet researchers are now exploring the efficacy of these agents when mixed with radiation therapy (RT).
This is similar to the synergistic effect of immunotherapy and chemotherapy combined in these patients, as experts are questioning whether administering RT while patients are receiving treatment with a PD-1/PD-L1 inhibitor could improve the significant, albeit often short, responses seen with checkpoint blockade.
“We are only beginning to scratch the surface with regards to combining these two independently potent modalities,” said Sagus Sampath, M.D. “Secondly, this is touching all stages of lung cancer…which is exciting. We are not just talking a small population of lung cancer patients who could benefit from this; this could really touch all of lung cancer.”
In an interview with CURE, Sampath, an associate clinical professor of radiation oncology, City of Hope, discussed the ongoing studies exploring checkpoint inhibitions with RT and the promise of integrating these two treatments in the field of NSCLC.
What combinations are being studied with these two modalities?
Basically, there are two main classes of immunotherapies. Now, people are focused on the PD-1/PD-L1 pathway so the drug therapies that are out there are mainly using mainly that two ligand and receptors. Targeting that with radiation is essentially where we are headed. It has been tested in a few clinical trials [across] a few patient populations. I spoke about that and the exciting possibilities of combining the two treatments, perhaps in stage IV patients.
Why might be there synergy with checkpoint inhibitors and RT?
A lot of individuals are not well informed about RT, other than it sounds really scary. However, it’s a focused treatment that is usually directed to a specific area in the body. For example, for lung cancer, the intuitive thing is to usually treat the chest. However, as we know, lung cancer can go to different places and, once that happens, we want to figure out — besides just giving drug therapies — is there something else we can give to make the systemic therapy better?
What we are trying to scratch the surface of is to understand, hopefully, more as time goes on, is if we give RT to a distant spot at the same time the patient is getting their systemic therapy, perhaps we could make the drug therapy work even better. That [involves] understanding the biology and the underlying mechanisms behind that; that is where the current research is being done. It’s an exciting time.
There is a lot there that we don’t really understand. Will we be able to extend patients’ lives? That will be the bottom line as to how this combination gets judged. In the next three to five years, we will be able to have an answer.