Perhaps if we delve deeper into the performance of TLX591 on the study I referenced (so that we are not accused of being selective by simply presenting what's on the abstract), here are some highlights from the full report.
The primary endpoint was safety, and the secondary endpoint is stated as: '... the rate of disease progression based on follow-up PSA levels and PSMA-PET imaging ...' I wrote this in bold because some of my TLX friends have changed their minds! They are now dismissing the value of PSA levels as a measure of disease progression, when it was ok to use it on the studies they quote as showing better or similar results to Pluvicto!
The drug administration was as follows;
a) Cycle 1: 1.08–2.68 GBq of Lu-TLX591 based on their baseline blood results and clinical frailty.
b) Cycle 2 - depending on the patient’s reported side effects and laboratory toxicity after the first cycle: 1.01–2.85 GBq of Lu-TLX591
c) Cycle 3 - In the absence of dose-limiting toxicity (DLT), a single repeat dose was administered after 14 days.
(I know someone who would have said straightaway that this dosing schedule wont work - its rushing an underdosed drug to market - Clarity don't do that)!
COMMENTS: For comparison: 1) Pluvicto was dosing at 7.8GBq in their trials
2) Clarity dosing was at 4GBq to Cohort 1, 8GBq to Cohort 2, and 12GBq to Cohort 3.
RESULTS
SAFETY
I wont focus on safety simply because - IF the treatment had worked, then perhaps it would have been worthwhile!
But in short, over 50% had hematological adverse effects, and one had DLT.
EFFECTIVENESS
PSA as a marker of response to treatment
- 38% had ANY PSA decline! (versus 100% in SECURE)
- 33% had NO change
- 38.9% got worse
Imaging (using 68Ga-PSAMA-11)
- 1 patient improved
- 50% had no change
- 41% got worse
For comparison: The still small SECURE STUDY has already had more successes than this 18 patient cohort that evaluated TLX591!
REFERENCE
Nguyen H, Hird K, Cardaci J, Smith S, Lenzo NP. Lutetium-177 Labelled Anti-PSMA Monoclonal Antibody (Lu-TLX591) Therapy for Metastatic Prostate Cancer: Treatment Toxicity and Outcomes. Mol Diagn Ther. 2024 May;28(3):291-299. doi: 10.1007/s40291-024-00699-w. Epub 2024 Mar 6. PMID: 38446353; PMCID: PMC11068829.
(20min delay)