The use of immunotherapies in the treatment of metastatic cancers has significantly advanced oncology. However, due to safety concerns, solid organ transplant recipients (SOTRs) are routinely excluded from immunotherapy trials; thus, there is limited data for these agents in this population.

A systematic review was performed to evaluate the safety and efficacy of immunotherapies in SOTRs with metastatic cancers. Fisher's exact test and Kruskal-Wallis test were used for analysis.

In total, 37% of patients experienced organ rejection, and 14% died as a result of graft rejection. Nivolumab was associated with the highest rejection rate (52.2%), followed by pembrolizumab (26.7%) and ipilimumab (25%; P = .1774). The highest rejection rate was seen in patients with kidney transplants (40.1%), then liver (35%) and heart (20%) transplants (P = .775), and 64% of patients succumbed to the progression of malignancy. For all cases, rates of progression or death secondary to disease were highest for ipilimumab (75%), followed by nivolumab (43%) and pembrolizumab (40%; P = .1892). The overall response rate was highest for pembrolizumab (40%), followed by nivolumab (30%) and ipilimumab (25%; P = .7929).

The small sample size.

Physicians must be cautious when administering immunotherapy to SOTRs. However, rejection is not the most common cause for death in this population.