The research reveals the effectiveness of the mixture of radionuclide remedy and immunotherapy within the prostate most cancers mannequin

A combination of radionuclide therapy and immunotherapy has been shown to be successful in slowing the progression of prostate cancer and increasing survival time. This is evident from new research published in the February issue of the Journal of Nuclear Medicine. The results of the mouse study show that radionuclide therapy enhances the immunogenicity of prostate cancer and elicits a cellular response that makes the tumors more susceptible to immunotherapy.

Prostate cancer is widely viewed as an immunological cold cancer for which immunotherapies have had only moderate success. However, increasing the immunogenicity of prostate cancer with prostate specific membrane antigen (PSMA) radionuclide therapy could make immunotherapy more successful. In our research, we tried to exploit this effect by combining radionuclide therapy with immunotherapy in a mouse model of prostate cancer. "

Katharina Lückerath, PhD, Assistant Professor of Preclinical Theranostics, University of California, Los Angeles, California

In the study, mice with prostate cancer tumors received one of four treatments: an isotope control antibody, a 225Ac-PSMA617 radionuclide therapy, an anti-PD-1 antibody, or both 225Ac-PSMA617 radionuclide therapies and an anti-PD-1 antibody. The therapeutic efficacy was assessed by measuring tumor volume (with computed tomography), time to progression, and survival.

While 225Ac-PSMA617 radionuclide therapy and PD-1 blockade alone tended to increase the time to progression compared to isotope control (30 days and 33.5 days versus 25 days, respectively), 225Ac-PSMA617 radionuclide therapy combined and PD-1 blockade significantly improved time to progression (47.5 days). Survival time also increased significantly for the joint therapeutic approach (51.5 days) compared to radionuclide therapy with 225Ac-PSMA617 (32 days), anti-PD-1 (37 days) and the control (28 days).

"These results suggest that radionuclide therapy can have a profound impact on the tumor immune microenvironment that can facilitate immunotherapies in prostate cancer," noted Lückerath. "Radionuclide therapy and immunotherapy combinations are promising therapeutic options for prostate cancer patients, and the data reported in our study support the clinical translation of radionuclide therapy-immunotherapy combination regimens."

In addition to this study, recently launched clinical trials on the treatment of prostate cancer and new tracers designed to map immune responses underscore the keen interest in studying immunity using molecular imaging and in combining radionuclide therapy with immunotherapy. According to Lückerath, these initiatives could expand the scope of nuclear medicine to include immunology and strengthen nuclear medicine 's ability to offer powerful and versatile treatment options.

This study was made available online in July 2020 before being finally published in print in February 2021.

Source:

Society for Nuclear Medicine and Molecular Imaging

Journal reference:

J. Czernin et al. (2021) Blocking the immune checkpoint improves the efficacy of 225Ac-PSMA617 in a mouse model of prostate cancer. Nuclear Medicine Journal. doi.org/10.2967/jnumed.120.246041.

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