Lower dose prostate cancer treatments found to retain efficacy while improving tolerability

Medical Xpress / Society of Nuclear Medicine and Molecular Imaging / Journal of Nuclear Medicine ^ | July 24, 2024 | Hendrik Rathke et al

[ConservativeMind]

Two reduced dose radiopharmaceutical therapy approaches for advanced stage metastatic castrate-resistant prostate cancer have been shown to be just as effective as the standard dose, according to research.

Treatment with deescalated 225Ac-PSMA-617 or a cocktail therapy of 177Lu/225Ac-PSMA-617 resulted in similar median overall survival and prostate specific antigen (PSA) response rates as the standard 225Ac-PSMA-617 dose and was better-tolerated.

The standard dose for 225Ac-PSMA targeted radiopharmaceutical alpha-therapy is 100 kBq per kilogram of body weight or an approximation of eight MBq.

"Preliminary data has shown that reduced doses result in lower rates of dry mouth while still maintaining promising anti-tumor activity," said Hendrik Rathke, MD.

"In our study we aimed to determine the tolerability, PSA response rate, and overall survival observed in patients who received a regimen of less than 100 kBq of 225Ac-PSMA or an 177Lu/225Ac-PSMA-617 cocktail therapy."

Researchers conducted a retrospective analysis of 233 patients who were treated with 225Ac-PSMA at Heidelberg University Hospital from 2014-2022; 104 received a median of six MBq of 225Ac-PSMA monotherapy and 129 received an 177Lu/225Ac-PSMA-617 cocktail therapy.

Of the patients who received 225Ac-PSMA monotherapy, 55 patients (53%) presented with a best PSA response of at least 50%. In the 177Lu/225Ac-PSMA-617 cocktail group, a best PSA response of at least 50% was observed in 74 patients (57%). The median overall survival was nine months in the 225Ac-PSMA monotherapy and was 15 months in the 177Lu/225Ac-PSMA-617 cocktail group. The efficacy of both regimens was not significantly different.

"The baseline prognostic characteristics of patients in this study are worse than patients who were recruited to the VISION clinical trial, yet the median overall survival and PSA response rates are equivalent," noted Rathke. "This leads to the assumption that patients with late stage prostate cancer can benefit from targeted radiopharmaceutical alpha-therapy."

[ConservativeMind]

Sometimes, therapy still works fine, when reduced, while providing fewer side effects.

It looks like advanced prostate cancer has one such example.

[ConservativeMind]

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[Sacajaweau]

My son is undergoing a treatment for bladder cancer...and they have been reducing the dose....and much more tolerable now. Hoping the efficacy results are similar to this. Another Pet Scan soon...