When we expect of radiation therapy, we often picture tumor treatment with a machine positioned outside the body. Now imagine a unique scenario – one through which radioactive particles entering the bloodstream hunt down and destroy individual cancer cells, while leaving healthy cells unharmed.
medicine
One such “radiolgand” is already available for some prostate cancer patients. Called Lu-PSMA-617 (trade name Pluvicto), it comprises a lethal payload of radioactive atoms. The drug binds to a cell protein called prostate-specific membrane antigen (PSMA), which is abundant on most prostate cancer cells but absent from most traditional cells. After binding to this protein, Lu-PSMA-617 delivers its radioactive cargo, after which the targeted cell dies.
As it currently stands, Lu-PSMA-617 is simply approved for one specific situation: eligible patients should have already been treated with chemotherapy for metastatic castration-resistant prostate cancer (mCRPC). During this advanced stage of the disease, prostate-specific antigen (PSA) levels rise despite treatments that block testosterone, a hormone that fuels prostate cancer growth (a rising PSA indicates It happens that the cancer is growing).
Doctors often respond by switching to other hormonal treatments that block testosterone in other ways. If those drugs don't work or turn into ineffective, chemotherapy will likely be the subsequent option.
But can men with mCRPC bypass chemotherapy — with its difficult unwanted effects — and begin Lu-PSMA-617 straight away? Investigators evaluated this potential strategy during a newly accomplished clinical trial.
the study
The first phase 3 trial of PSMA enrolled 468 men with mCRPC. All men had PSMA-positive tumors, and every had already been treated with a second-line testosterone blocker. For most men, that drug was abiraterone. The rest were treated with a drug called enzalutamide. None of the lads had yet received chemotherapy.
Investigators randomized all enrolled men into two groups. Men within the treatment group got an infusion of Lu-PSMA-617, while men within the control group were switched to a different testosterone blocker that they had not yet received.
Facts and evidence
After a few yr and a half of follow-up, the Lu-PSMA-617 treatment developed. Promising results. Importantly, the treated men avoided further cancer progression for a median of 1 yr, which was six months longer than the progression within the control group.
Lu-PSMA-617 also produced a big decrease in PSA: in 58% of men treated with Lu-PSMA-617, PSA levels dropped by half or more. Only 20% of men within the control group experienced a comparable decrease in PSA. Lu-PSMA-617 was also well tolerated. The most typical unwanted effects were dry mouth and minor gastrointestinal symptoms, and treated men also reported less pain and a greater quality of life.
Tafsir
Dr. Garnick added, “This study marks one other advance in our emerging treatment options for men with advanced prostate cancer, and sheds light on the mechanisms of pharmaceutical development. When recent treatments are introduced , in order that they are studied in patients in whom treatment options are limited. Fortunately, Lu-PSMA-617 has shown excellent leads to this population, and the study described here suggests that this treatment could also be transferrable to early types of advanced prostate cancer, we anxiously await long-term follow-up of this necessary research.”