Ofatumumab Treatment for Refractory Generalized Myasthenia Gravis Post-Lung Adenocarcinoma Resection: A Case Report...

Myasthenia gravis (MG), an autoimmune neuromuscular disorder, may rarely coexist with malignancies such as lung cancer.

This case report presents the first documented use of ofatumumab, a fully human anti-CD20 monoclonal antibody, in a 75-year-old female with acetylcholine receptor (AChR)-antibody-positive generalized MG (gMG) following lung adenocarcinoma resection. Initially diagnosed with ocular MG (MGFA Class I), the patient progressed to refractory gMG (MGFA Class IIIa) post-thymectomy and tumor resection, unresponsive to corticosteroids, tacrolimus, and intravenous immunoglobulin. Due to persistent symptoms and steroid-induced complications, subcutaneous ofatumumab (20 mg on Days 1, 7, and 14) was administered off-label. Rapid clinical improvement was observed, with Myasthenia Gravis Composite (MGC) and MG Activities of Daily Living (MG-ADL) scores declining from 20 to 10 and 17 to 10, respectively, within weeks. Minimal manifestation status (MMS) was sustained for 2 years with intermittent ofatumumab re-administration (triggered by CD19/CD20 + B-cell reconstitution > 1%), alongside no tumor recurrence or adverse events.

This case highlights ofatumumab's potential efficacy and safety in managing refractory gMG post-cancer resection, possibly via robust B-cell depletion and reduced immunogenicity. These findings advocate for targeted B-cell therapies as a viable strategy in complex, refractory MG cases, particularly where conventional immunosuppressants pose oncological concerns.