Efficacy of anti-PD-1 drugs on cancer regression

This review provided the long-term outcomes of the first human trial of the anti-PD-1 drug BMS-936558. It also evaluated whether restarting therapy for cancer recurrences can be effective. Results showed that anti-PD-1 drugs have clinical potential.

The PD-1 protein (or "programmed cell death-1" protein) plays a major role in the body's ability to mount an immune response against cancer. High levels of PD-1 are associated with weaker immunity, while low levels lead to excessive immune responses. Drugs aimed at blocking PD-1 are currently under investigation for the treatment of various cancers, as modulators of the body's own defenses against tumors. It is hypothesized that a stronger immune response might help fight the cancer.

BMS-936558, a drug that specifically blocks PD-1 was administered for the first time in a human study. Participants had various types of metastatic cancers, including colorectal. In 3 of the 39 patients who received the treatment, the tumors were significantly reduced. One of the durable responses was in a patient with metastatic colorectal cancer (spread to distant organs) and multiple previous chemotherapy regimens. After 5 doses of the anti-PD-1 drug, there was a complete disappearance of all signs of cancer. 3 years after treatment there was no recurrence of the disease.

In conclusion, the successful application of PD-1 blockers underscores the importance of immunotheraphy, especially in CRC. Data from this study should stimulate further research investigating the PD-1 levels as a predictor of therapy response.

While these results are encouraging, it is important to note the small number of participants and the fact that only one patient achieved a complete response. The safety of anti-PD-1 drugs still needs to be assessed in larger trials.