From NEJM review:
Immune checkpoint blockade is an increasingly important cancer treatment. Several studies have shown that it has a better safety profile than chemotherapy.
Immune checkpoint blockade increases antitumor immunity by blocking intrinsic down-regulators of immunity, such as:
- cytotoxic T-lymphocyte antigen 4 (CTLA-4) (1 antibody approved by FDA)
- programmed cell death 1 (PD-1) (2 antibodies)
- programmed cell death ligand 1 (PD-L1) (3 antibodies)
CTLA-4 inhibits an immune response in several ways, including attenuating T-cell activation at a proximal step in the immune response. In contrast, PD-1 inhibits T cells at later stages of the immune response in peripheral tissues.
Most of the toxic effects are reversible, aside from effects on the endocrine system, which may be permanent.
The NEJM review discussed the adverse effects of these medications in detail (see the link below).
Immune-Related Adverse Events Associated with Immune Checkpoint Blockade — NEJM http://bit.ly/2qX9Nhc