Noxopharm (ASX:NOX) has released details of the radiographic review of its DARRT-1 clinical study and says it shows a major benefit from a combination of Veyonda and low-dose radiotherapy.
The company is using the DARRT trial to study the use of a low dose of radiation to trigger an immune response to the cancer in one particular tumour, with Veyonda then promoting a generalised spread of that immune response to tumours elsewhere in the body.
Dr Graham Kelly, Noxopharm CEO, said, “This is an exciting outcome that vindicates our belief in the anticancer properties of Veyonda.
“There is growing interest in using combination targeted radiotherapy and immunotherapy drugs such as checkpoint inhibitors, with reports of some abscopal responses being obtained in certain cancers such as breast, lung and urological cancers and melanoma.
"But to our knowledge, this is the first time that anyone has been able to obtain a meaningful abscopal response rate in prostate cancer. Prostate cancer has developed a reputation as a cancer with poor immune responsiveness, but this DARRT-1 data suggests that this isn’t the case.
"Today’s result positions Veyonda at the forefront of this emerging area of oncology and suggests that we have an exciting new prospective treatment for end-stage prostate cancer.”
DARRT-1 patients were selected for having both soft tissue and bone secondary tumours. Radiation was delivered to one or two symptomatic lesions – be they soft tissue or bone lesions. Then all measurable lesions, both irradiated and non-irradiated, were followed up.
To qualify as an abscopal response, the non-irradiated lesion(s) need to be outside the radiation field.
Radiation was delivered by low-dose external beam to one or two lesions at a dose of 20Gy for 5 days. Veyonda was given daily for 10-14 days.
According to Dr Gisela Mautner, Noxopharm chief medical officer, “Abscopal responses are a very rare occurrence, so to see it in 4 of 15 patients is a remarkable result. Considering that this was an early phase study with only a short course of Veyonda, these results become even more exciting.
“Taking all the results together that we have seen in the DARRT-study, i.e. the pain reductions, the PSA responses and the responses in the tumour sizes, we can certainly say that many of the patients derived a great benefit from Veyonda. This makes the next DARRT study even more urgent as there are many prostate cancer patients out there waiting for better treatment options and hoping to live longer."