Checkpoint inhibitors are now frequently used for oncologic conditions. The impact of these therapies in solid organ transplant recipients was not assessed in clinical trials. Subsequent case reports highlight the major detrimental interactions of checkpoint inhibitors and the high risk of allograft rejection with their use, although patient outcomes have not yet been assessed in long-term follow-up.

We conducted a retrospective review of kidney transplant recipients with metastatic cancer who received checkpoint inhibitors at a single center between April 2015 and May 2018.

Six kidney transplant recipients with metastatic cancers that were not responding to first-line treatments met study criteria. These include two with squamous cell cancers, two with melanoma, one with renal cell cancer, and one with adenocarcinoma of the lung. Four patients received anti-programmed cell death protein-1 (PD-1) antibody and two received a combination of anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and anti-PD-1 antibodies. Three out of six patients developed acute kidney injury. Two were biopsy-proven acute rejections with subsequent graft failures. The third was attributed to rejection, but improved after discontinuing the checkpoint inhibitor. Five out of six patients had cancer progression and only one patient had remission.

Providers and patients need to be aware of the high risk of rejection and the poor remission rate with the use of checkpoint inhibitors in kidney transplant patients. More research is warranted to assess the optimal maintenance immunosuppression during the use of checkpoint inhibitor therapy that would not diminish the chances of remission.

Transplantation. 2019 Aug 09 [Epub ahead of print]

Karthik Venkatachalam, Andrew F Malone, Brittany Heady, Rowena Delos Santos, Tarek Alhamad