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Medicine Matters oncology

The VISION trial will be reported at ASCO. And it's a very positive trial. And clinicians, like myself, are excited to have a new treatment for our patients with advanced metastatic castration-resistant prostate cancer.



When talking to patients about the VISION trial, several things will be important to understand. The first is that patients, one, on this trial were required to have a specialized type of PET scan called a PSMA PET scan. PSMA is a protein on the surface of prostate cancer cells. The majority of patients by the definition of a positive scan in the VISION trial were positive.



About 87% of them were positive. So in all likelihood, your patients when they screen and have the PET scan, will be eligible for this type of treatment. The patients, in general, who are on the VISION trial had been previously treated with one second generation, at least one second generation androgen-receptor access inhibitors, such as abiraterone or enzalutamide, and at least one chemotherapy, such as docetaxel or cabazitaxel.



And patients who fit that category, positive PET scan previously treated with abi or enza and chemotherapy would be good candidates to consider for radiopharmaceutical treatment. In this case, particularly with PSMA lutetium. And what the study showed was that the median overall survival of the patients who were treated with lutetium PSMA improved by four months. So for some patients, it may be a little less and for some patients a little more, but that's what it was in this particular group of patients who were fairly advanced in their disease course.



The survival of the control group was 11 months. In addition, a very positive aspect of this treatment is that the radiographic progression-free survival was improved by almost six months. In addition, there was a high PSA response rate.



So I believe that a patient's quality-of-life is significantly improved when they know a treatment is working against their cancer by direct readouts that we have, such as PSA and stable or improving scans. So that's a nice benefit of this type of treatment. The side effects that we're seeing on this treatment were, in my opinion, fairly tolerable for cancer therapy.



There was some fatigue seen, some dry mouth, and some nausea, very occasionally vomiting. And there has to be a discussion with patients about potential bone marrow toxicity, because this type of treatment does affect the blood counts, especially in patients who've been previously treated with chemotherapy, but it was quite manageable. And I myself had about a dozen patients on this trial.



And what we're seeing in the trial was about 13% of patients needed a blood transfusion. And that was compared to 5% in the control. So we do see blood transfusions given in this population of patients, in general.



So with the new data that we presented at ASCO, it will be published in the New England Journal of Medicine. It's just the beginning. There's a lot to learn about this compound, in particular, and radiopharmaceuticals, in general, in prostate cancer and in lots of other cancers. The majority of cancers would be suitable for this type of targeted radiotherapy.



For prostate cancer, in particular, we have questions surrounding would this treatment be more effective if given earlier in the course of prostate cancer? Could we improve efficacy by combining it with other treatments? Other treatments could be external beam radiation, immunotherapy, PARP inhibitors.



So I think we'll see a lot of trials asking these questions over time. And I have a personal interest in the dosing. It's one of the reasons for failure that we're not getting enough radiation into prostate cancer that's in little nests of cancer cells in a dense form of bone marrow. So I think a lot of questions need to be answered as progress unfolds in this area about the right dosing and schedule to adequately kill cancer cells in the bone, in the bone marrow in the case of prostate cancer.