767 - Acute Onset Peripheral Neuropathy Associated with Monoclonal Antibody Treatment Pembrolizumab

Friday, February 23, 2024

5:00 PM – 6:30 PM EDT

Presenting Author(s)

AG

Alyson Galanga, BS

Medical Student
McGovern Medical School UT Health Houston
Houston, Texas, United States

Co-Author(s)

PV

Peter D. Vu, MD

Resident Physician
University of Texas Heath Science Center at Houston, TIRR Memorial Hermann
Houston, Texas, United States
CG

Carolina Gutierrez, MD

Physician
McGovern Medical School
Houston, Texas, United States

Case Diagnosis: We present a case of a 53-year-old male with stable stage four bladder cancer, receiving a commonly used monoclonal antibody treatment, pembrolizumab, who developed acute onset rapidly progressing peripheral neuropathy and weakness in bilateral upper and lower extremities.

Case Description: The patient is a 53 year old male with a history of Neurofibromatosis Type 1 (NF1) and stable bladder, who was referred to Physical Medicine and Rehabilitation (PM&R) clinic. Patient described 5 months of progressive foot drop, gait instability, and abnormal sensation in bilateral lower extremities. Previous electromyography (EMG) findings suggested a demyelinating process, likely secondary to pembrolizumab-induced peripheral neuropathy. The patient had no prior neurological deficits and was independent in all activities of daily living (ADLs) and instrumental activities of daily living (iADLs).The patient received intravenous immunoglobulin (IVIG) without complications. Lumbar puncture showed normal glucose and protein levels. After the second dose of IVIG, the patient reported mild improvement in the right foot and toe dorsiflexion.

Discussions: Pembrolizumab is a monoclonal antibody used in cancer immunotherapy. While chemotherapy-induced peripheral neuropathy is a well-known phenomenon, the occurrence of similar symptoms with monoclonal antibody therapy is rare. This case highlights the significance of recognizing the potential side effects of pembrolizumab, particularly in patients with pre-existing peripheral sheath pathologies like NF1.

Conclusions: This case underscores the importance of considering pembrolizumab as a potential cause of acute onset peripheral neuropathy in patients receiving monoclonal antibody therapy. In the realm of cancer rehabilitation, the identification and management of treatment-related side effects are essential. Although pembrolizumab is not a traditional chemotherapy agent, the side effect of peripheral neuropathy observed in this case can have profound implications for functional independence and rehabilitation outcomes. Rehabilitation professionals should be vigilant in monitoring patients undergoing immunotherapy for any signs or symptoms suggestive of peripheral neuropathy.