Efficacy and Safety of Glembatumumab Vedotin in Patients With Advanced or Metastatic Squamous Cell Carcinoma of the Lung (PrECOG 0504)

Introduction Glycoprotein NMB is a transmembrane protein linked with poor prognosis and is expressed in most squamous lung cancer. Glembatumumab vedotin is an antibody-drug conjugate targeting glycoprotein NMB, administered intravenously every 3 weeks in this phase 1 study to determine the safety, tolerability, and maximum tolerated dose in patients who had progressed on any number of previous therapies. Results A total of 13 patients were enrolled; adverse events (of any grade) including dyspnea, neutropenia, respiratory failure, anemia, increased aspartate transaminase/alanine transaminase, diarrhea, and hypophosphatemia were seen in 15% of patients. Grade 5 events included two cases of respiratory failure, either completely or partially attributed to cancer progression. The only other grade 5 event was “disease progression.” The most common adverse events (23%) were decreased appetite, fatigue, rash, and weight loss.The median overall and progression-free survivals were 5.7 months (90% confidence interval: 2.5–16.8) and 2.5 months (90% confidence interval: 1.6–5.8) respectively. Conclusions Glembatumumab vedotin exhibited no serious or unexpected toxicity in this heavily pretreated population, except those caused by disease progression. Modest anticancer activity was observed with a recommendation for a phase 2 dose of 1.9 mg/kg. This portion of the study was not undertaken owing to the company’s decision to discontinue drug development.