The LUNAR study was a single center randomized phase 2 trial that we conducted at UCLA with my buddy and colleague Amar Kishan, radiation oncologist, main PI. I serve as the co-PI on the nuclear medicine side. We wanted to test the hypothesis of adding two cycles of lutetium PSMA therapy before SBRT in patients with oligometastatic recurrent hormone-sensitive prostate cancer...
The LUNAR study was a single center randomized phase 2 trial that we conducted at UCLA with my buddy and colleague Amar Kishan, radiation oncologist, main PI. I serve as the co-PI on the nuclear medicine side. We wanted to test the hypothesis of adding two cycles of lutetium PSMA therapy before SBRT in patients with oligometastatic recurrent hormone-sensitive prostate cancer. So we randomized patients into two groups, 45 patients per group. And in the control group, patients had standard of care SBRT. And in the intervention group, patients had lutetium PSMA, two cycles neoadjuvant plus SBRT. And then we followed up the patients in both groups with PSA every three months. And interestingly, with PSMA PET scan systematically at 12 months and at 24 months and at each PSA rise. The main findings, the PFS, which was the primary endpoint based on PSMA PET scan, was 17 months in the investigational group versus seven months in the control group. So the hazard ratio was 0.37. Of note, all the progression events were mostly new lesions outside of the fields. Another main finding of the study is the hormonal therapy-free survival. Hormonal therapy-free survival was initiated in case of new lesions on a PSMA-PET scan or a PSA above 10 if there were no new lesions. And it was 24 months in the investigation group versus 16 months in the control group. So a hazard ratio of 0.40. So this is, I think, very relevant for patients who are trying to avoid ADT and delay the initiation of ADT. In terms of toxicity, it was very well tolerated. It was a low dosing schedule, 6.8 gigabecquerel, eight weeks time interval, so pretty much on the lower range in terms of dosing. And so there were a little bit of grade one, bone marrow toxicity, dry eyes, dry mouth, and diarrhea, but low frequency, no more than 5%. So as a conclusion, in this phase two randomized trial, we show that by PSMA PET-based progression for survival, two cycles of Lutetium PSMA therapy neoadjuvant to SBRT was improved in comparison to SBRT only. The toxicity profile was very good. I think the effect is mostly that Lutetium PSMA is treating the microscopic disease that we don’t see on the PSMA PET scan. The visible lesions on the PSMA PET scan, they were covered by radiation therapy. Still, we can do better. There were 60% of the patients in the investigation group who progressed ultimately. So maybe we can improve the dosing schedule. Maybe we can also use alpha emitters rather than beta emitters because they are more suitable for treating microscopic disease. Next phase, we will try to go to the phase three. And so we’re designing that now.
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