Immunotherapy Drug Shows ‘Dramatic Responses’ for Some Men With Prostate Cancer
Fri, December 3, 2021

Immunotherapy Drug Shows ‘Dramatic Responses’ for Some Men With Prostate Cancer

Some men living with prostate cancer could extend their lives by at least two years with immunotherapy drugs, results from a new clinical trial show / Photo by: Image Point Fr via Shutterstock

 

Some men living with prostate cancer could extend their lives by at least two years with immunotherapy drugs, results from a new clinical trial show.

Published in the Journal of Clinical Oncology, the study showed that immunotherapy can work for some patients with end-stage prostate cancer and debunked the previous notion that the method wouldn't work for this cancer type.

While the turnout was relatively small, the researchers from the Institute for Cancer Research (ICR) noted the "dramatic response" that helped some of the patients gain additional years even after the clinical trial ended.

 

Treatment With Immunotherapy

There isn't much activity observed in the immune system when it comes to prostate tumors, which is why many experts believed immunotherapy won't work for the condition. However, the recent study proved that this doesn't apply to certain men with end-stage cancer, who were found to respond and do very well after treatment.

In their study, the researchers recruited 258 men with advanced prostate cancer and became resistant after treatment with androgen deprivation therapy and docetaxel chemotherapy. They were given pembrolizumab (also known as Keytruda).

The results of the trial showed the tumors of the 5% of the men treated with immunotherapy shrunk or disappeared. Another 19% also had some evidence of tumor response from the treatment, Science Focus reports. Science Focus is BBC's monthly magazine on science and technology providing the latest news for general readers and those with knowledge in science.

It adds that the study also found an average length of survival of 8.1 months among the 166 patients with an advanced stage of the disease and high prostate-specific antigen (PSA) levels. Notable results were found in nine of these patients, who saw their disease either partly or completely disappear.

Among those nine patients, four were considered "super-responders" after remaining on the treatment at the end of the study follow-up and found that the effects lasted for at least 22 months. Another group with lower PSA levels, but whose disease had spread to the bone, lived for an average of 14.1 months.

The researchers concluded that pembrolizumab was well-tolerated, according to Science Focus, as 60% of patients reported any side effects and merely 15% had grade three to five side-effects.

In their study, the researchers recruited 258 men with advanced prostate cancer and became resistant after treatment with androgen deprivation therapy and docetaxel chemotherapy / Photo by: Tyler Olson via Shutterstock

 

An Emerging Goal

The results of the study were significant despite only a small number of the patients responding positively to the treatment. For other cancer patients, immunotherapy has provided tremendous benefits during their treatment and "it's fantastic news" that it can also reap the same outcomes for a proportion of men with prostate cancer, according to ICR chief executive Paul Workman.

Now, the researchers are looking to determine why these few "super-responders" had significant responses to pembrolizumab when it didn't work for most of the other patients. Last year, the same team reported that men who had defects in certain proteins involved in repairing DNA seemed to also respond well to the immunotherapy drug.

"We found that men with mutations in DNA repair genes respond especially well to immunotherapy, including two of my own patients who have now been on the drug for more than two years," said Johann de Bono, Regius Professor of Cancer Research at the ICR, as per business magazine Forbes.

De Bono noted that a larger-scale clinical trial is currently being conducted to investigate this.

Forbes reports that the ICR team hopes they can accurately distinguish patients who will and won't responsive to the drugs by determining the reason for the outcomes of the few men in their study. It adds that ongoing trials that combine pembrolizumab with other drugs targeting DNA repair processes may help in allowing some non-responders to be more sensitive to the immunotherapy.

Significant Need for Effective Treatment

Prostate cancer is the second most common cancer among men and the fifth leading cause of death worldwide. Global estimates show that 1,276,106 new cases were recorded in 2018, with developed countries showing higher prevalence, representing 1.7% of all cancers in men.

While only 1 in 350 men below 50 years old will be diagnosed with the disease, the incidence rate climbs up to 1 in every 52 men aged 50 to 59. Prevalence will continue to climb with rates reaching nearly 60% in men over 65 years old.

Prostate cancer is highly treatable, but only in its early stages. The ICR says the treatment of early-stage prostate cancer shows a five-year survival rate of nearly 100%, the Daily Mail reports. However, advanced prostate cancer—when cancer has spread to another body part—lowers the five-year survival rate down to less than 30%.

This highlights the significant need for more effective treatment of the advanced stage of the disease, the Daily Mail notes. With the findings of the ICR study, that need may come into realization after larger studies are conducted and develop new immunotherapy approaches that work for more men.