Australian clinical-stage drug development company Noxopharm Limited (ASX:NOX) has unveiled two developments relating to the use of Veyondaâ to enhance the survival benefit of 177lutetium-PSMA-617 (LuPSMA) treatment in men with metastatic castrate-resistant prostate cancer.
The first of these developments is important pre-clinical evidence confirming the ability of Veyonda to enhance the cancer-killing effect of LuPSMA treatment. The study was conducted by a research group led by Professor Kristofer Thurecht at The University of Queensland and had the aim of separating a combination effect (Veyonda + LuPSMA) from that of either drug alone.
The combination of Veyonda with LuPSMA exhibited an impressive synergistic therapeutic response, with sustained and almost complete regression of the tumour and minimally-observed systemic toxicity,” Professor Thurecht said.
“This combined response was not observed in any of the animals treated with monotherapy.” The study involved mice bearing tumours of human PSMA-positive prostate cancer (PC3-PIP) cells. LuPSMA was dosed on a single occasion with the equivalent of a human dose; idronoxil was dosed (rectally) twice daily for 10 days.
“Tumour size was recorded and mice were euthanised when tumours reached a pre-determined size, leading to a calculation of median overall survival (time when 50% of animals had died). LuPSMA alone had a clear anti-cancer effect in this model, slowing down tumour growth and extending survival substantially.
“However, the addition of Veyonda had an even more profound anti-cancer effect, going beyond blocking tumour growth into full regression of most of the tumours, to the extent that median overall survival could not be determined.”
LuPIN trial
The second development is the publication of the LuPIN phase I/II clinical trial data in the highly respected The Journal of Nuclear Medicine
Noxopharm CEO , Graham Kelly, said the data is the more detailed version of a presentation in February 2021 to the American Society of Clinical Oncology (ASCO) GU meeting and reported to the ASX on 15 February 2021. The final tumour response data for this phase I/II study in 56 men is: 86% had a reduction in PSA levels; 61% had a PSA reduction >50%; median PSA progression-free survival was 7.5 months; median overall survival was 19.7 months.
“Men with prostate cancer that has spread and stopped responding to all available therapies have very limited survival prospects, generally in the order of five to eight months,” Mr Kelly said.
“Which is why a median overall survival outcome of 19.7 months in the LuPIN trial was so impressive. Based on the published survival experience of LuPSMA therapy alone, we were in little doubt that Veyonda had played a major role in that outcome.
“However, for some, the question of a combination effect versus a LuPSMA therapy alone effect remained, a question we are confident now has gone a long way to being answered by the animal study. In that study, LuPSMA on its own had an impressive anticancer effect, but nothing like the effect when Veyonda was added and the tumours mostly disappeared.
“We see Veyonda having a major commercial future in the rapidly growing field of radioligand therapy, not just in prostate cancer, but across the broad cancer spectrum. With a wide and growing number of companies developing novel radioligand drugs, this is a commercial opportunity that the Company is able to carve out as a separate market segment while it undertakes the other 3 programs, IONIC, DARRT and CEP, in its 4-pillars strategy.”
