Immune-Related Sclerosing Cholangitis and Subsequent Pyogenic Liver Abscesses in Two Patients With Melanoma Treated by Triplet Therapy: A Case Report.

Immune checkpoint inhibitors have improved the treatment of many cancers. However, immune-related (IR) adverse events can limit their use. A rare but potentially severe IR adverse event is IR-cholangitis, which is mostly induced by anti-programmed cell death 1 (PD1) antibodies and is often corticosteroid-resistant. Consequently, immunosuppressive therapy is increased, which interferes with the antitumor response and bears the risk of infection. We report on 2 patients with BRAF V600E mutant melanoma, who presented with IR-sclerosing cholangitis under triplet therapy with atezolizumab [anti-programmed cell death ligand 1 (PD-L1) antibody], vemurafenib (BRAF inhibitor), and cobimetinib (MEK inhibitor). In both cases, the administration of corticosteroids initially resulted in a marginal improvement but was followed by a rebound of biliary enzymes and the subsequent emergence of pyogenic liver abscesses with bacteremia. Liver abscesses developed without preceding invasive procedures, which implies that a more restrictive approach to immunosuppressive therapy for IR-cholangitis should be considered. To our knowledge, we report the first 2 cases of IR-cholangitis and subsequent liver abscesses without prior invasive intervention, the first cases of IR-cholangitis induced by triplet therapy, and 2 of the few anti-PD-L1 induced cases contributing to the evidence that both anti-PD1 and anti-PD-L1 antibodies induce IR-cholangitis. Treatment strategies for IR-cholangitis need to be improved to prevent life-threatening infectious complications.