(P-TA-10) Role Of Therapeutic Plasma Exchange In Immune Checkpoint Inhibitor Therapy-Induced Adverse Events

Background/Case Studies: Immune checkpoint inhibitors (ICI) are immunomodulatory antibodies with a promising anticancer role. However, there is an exponential rise in immune-related adverse events (irAE) with ICI use given autoreactive T-cells activation. We aim to study the role of therapeutic plasma exchange (TPE) in the treatment of refractory ICI-induced adverse events among cancer patients.

Study

Design/Methods: Six patients (5 females, 1 male) with ICI-induced adverse events were presented to our apheresis center between May 2022 to December 2022. A retrospective chart review was done for demographics, clinical history, TPE procedure details, and outcomes.

Results/Findings: The median age was 68.5 years (range: 41-92). Only 5 patients were treated with TPE. 1 patient died before TPE consideration. ICI-related adverse events included myocarditis (83%), myositis (33%), Myasthenia Gravis (MG) exacerbation (33%), hepatitis (16%), and Steven Johnson Syndrome (SJS)/toxic epidermal necrolysis (TEN) (16%). One patient (Patient #3) had a classic Triple “M” Syndrome: a triad of MG, myositis, and myocarditis presenting together. All patients were refractory to steroid treatment, while 50% were also treated with intravenous immunoglobulin (IVIG). TPE was done using 5% albumin as replacement fluid. Both MG patients (Patients #2 and #3) had significant neurological improvement. The triple “M” syndrome patient didn’t require additional TPE after initial 5 sessions. However, she experienced recurrent triple “M” syndrome 6 months later and still achieved full neurological recovery after 4 TPE sessions. The remaining, 3 patients had 2-3 TPE sessions each. Post TPE treatment, 3 patients were discharged to home or a step-down facility, 1 patient was discharged to hospice, and 1 patient died. None of the patients were retreated with ICIs. No procedure associated complications were noted.

Conclusions: We present cases with rare ICI-induced irAEs, such as recurrent triple “M” syndrome and SJS/TEN, to enrich the literature. Patients with MG-like presentation responded favorably to TPE treatment, even for recurrent symptoms although the neurological improvement seems optimal with the treatment conducted earlier.

Importance of research: ICIs have revolutionized the treatment of several advanced malignancies leading to durable remission in a subset of patients. Their rapidly expanding use has led to an increased frequency of immune-related adverse events (irAEs). PLEX may attenuate ongoing irAEs and prevent delayed irAEs by accelerating clearance of the ICI, or by acutely removing pathogenic antibodies, cytokines, and chemokines. Here, we summarize cases with spectrum of irAEs treated successfully with PLEX at our institution.