Reducing prostate cancer treatment dosage alleviates downsides while remaining effective
Reducing the dose of radiopharmaceutical therapy for prostate cancer patients improves tolerability without sacrificing efficacy, according to new research published in the Journal of Nuclear Medicine.
For the work, a team examined the effects of differing doses of 225Ac-PSMA-617 or a cocktail therapy of 177Lu/225Ac-PSMA-617 specifically. According to their research, reducing these treatment doses by around 25% and 50% still maintains PSA response rates, but eliminates some of the unwanted side effects often associated with therapy, such as dry mouth, experts involved in the research noted.
“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,” Hendrik Rathke, MD, from the Department of Nuclear Medicine at Heidelberg University Hospital in Heidelberg, Germany, and colleagues wrote. “Preliminary data from other studies has shown that reduced doses of PSMA treatment result in lower rates of dry mouth while still maintaining promising anti-tumor activity.”
The typical dose for 225Ac-PSMA targeted radiopharmaceutical alpha-therapy is 100 kBq per kilogram of body weight, or around eight MBq. For the study, one group of participants (144) received a reduced dose of around six MBq, while another (129 total) was given a lower dose of 4 MBq of a 177Lu/225Ac-PSMA-617 cocktail therapy. PSA responses and overall survival rates were used to measure treatment efficacy.
In the group that received 225Ac-PSMA monotherapy, a PSA response rate of at least 50% was observed in 53% of participants, while 57% of the cocktail therapy group achieved the same response. The monotherapy group recorded a median overall survival of nine months; the overall survival in the cocktail group was a bit longer, at 15 months, but the team noted that after adjusting for prognostic baseline characteristics, the differences between the groups were insignificant.
“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,” the group explained. “This leads to the assumption that patients with late stage prostate cancer can benefit from targeted radiopharmaceutical alpha-therapy.”
Encouragingly, none of the patients discontinued treatment due to side effects related to dry mouth.
The study abstract is available here.
In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She began covering the medical imaging industry for Innovate Healthcare in 2021.