Clinical Trials on Pembrolizumab (Keytruda) with metastatic prostate cancer have been mixed with 80% of patients seeing no real benefit and just 5% of patients doing very well.
In particular, those men having mutations in DNA repair genes seemed to respond better. About 5% of the 258 men in the study’s report (meaning other patients with side-effects or negative results may have fallen out during the study), saw their tumours shrink or disappear, while 19% of the total saw some signs of response. The 5% were dubbed ‘super-responders’.
The Phase II Clinical Trial was a global study led by the Institute of Cancer Research in London, and funded by the Royal Marsden Foundation.
The reports in the mass media that immunotherapy can beat prostate cancer border on hype and Professor Paul Workman, CEO of the Institute of Cancer Research, in London said he preferred to wait for the results of a larger scale trial.
Professor Johann de Bono at the Institute of Cancer Research, who led the trial however seemed excited by the results and the finding that, however small, there was a group of ‘super-responders’ to the immunotherapy, and these could live for a couple of extra years.
The Research was reported in the Journal of Clinical Oncology.
The men all had advanced metastatic prostate cancer and had used orthodox therapies. It is well known (2) that prostate cancer is less responsive to the immune system, has higher levels of cancer stem cells and more mutations present.
In a previous small scale trial of 28 patients (Keynote – 028; July 2018: 3) with metastatic prostate cancer, no patient had total response with 17.4% having partial response. In another (4) study of 38 men with metastatic prostate cancer, response was noted in men with lower PSA scores only.
Go to: CANCERactive overview on immunotherapy
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References
- https://medicalxpress.com/news/2019-11-prostate-cancer-super-years-immunotherapy.html
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6447686/
- Annals of Oncology July 2018; https://academic.oup.com/annonc/article/29/8/1807/5050822
- https://ascopubs.org/doi/abs/10.1200/JCO.2018.36.6_suppl.250