On July 8, 2022 MacroGenics, Inc. (NASDAQ: MGNX), a biopharmaceutical company focused on developing and commercializing innovative antibody-based therapeutics for the treatment of cancer, reported that effective as of July 7, 2022, the Company closed the Phase 2 study (CP-MGA271-06) evaluating the investigational regimen of enoblituzumab (Fc-optimized B7-H3-directed monoclonal antibody) in combination with either retifanlimab (anti-PD-1 monoclonal antibody) or tebotelimab (PD-1 × LAG-3 bispecific DART molecule) in the first-line treatment of patients with recurrent or metastatic squamous cell carcinoma of the head and neck (SCCHN) (Press release, MacroGenics, JUL 8, 2022, View Source [SID1234616572]).
Schedule your 30 min Free 1stOncology Demo!
Discover why more than 1,500 members use 1stOncology™ to excel in:
Early/Late Stage Pipeline Development - Target Scouting - Clinical Biomarkers - Indication Selection & Expansion - BD&L Contacts - Conference Reports - Combinatorial Drug Settings - Companion Diagnostics - Drug Repositioning - First-in-class Analysis - Competitive Analysis - Deals & Licensing
Schedule Your 30 min Free Demo!
The decision to discontinue the study was based on an internal review of safety data, which included the occurrence of seven fatalities potentially associated with hemorrhagic events in both arms of the study (of 62 total patients treated). Six of the seven fatal events observed in the CP-MGA271-06 study were assessed by investigators as secondary to disease progression and/or unrelated to the study treatment, and one event was assessed as possibly related. Fatal tumor-related hemorrhages and airway obstruction are known risks in patients with SCCHN. The incidence of fatal events observed in the study that were potentially hemorrhagic in origin was higher than what has been reported for this patient population in the medical literature (i.e., 1 – 3.6% as per Argiris, et al., J Clin Oncol. 2019 Dec 1, 37(34):3266) and in the context of a risk : benefit analysis, prompted the Company’s decision to close the study. Accordingly, the Company informed investigators and the U.S. Food and Drug Administration (FDA) of the study closure and instructed investigators that no additional patients in the study were to be enrolled or receive further treatments as of July 7, 2022.
MacroGenics continues to investigate and monitor these events, and an analysis of the data is ongoing. There were no hemorrhagic events or coagulopathies observed in nonclinical toxicology studies of enoblituzumab, and the incidence of any fatal hemorrhage reported in earlier studies of enoblituzumab evaluated in over 340 patients across a broad range of tumor types was less than 1%.
"Our top concern in conducting clinical trials is the safety of study participants," said Scott Koenig, M.D., Ph.D., President and CEO of MacroGenics. "We were surprised by the emergence of these events in first-line SCCHN patients, as we had not observed any such events in an earlier, smaller study in patients with later-line SCCHN disease who were treated with enoblituzumab in combination with an anti-PD-1 antibody. Similar safety events have not been reported in patients treated with MGC018, our B7-H3-targeted ADC molecule, and the decision to close the CP-MGA271-06 study does not impact our ongoing MGC018 study activities. We’d like to thank all patients, their families and caregivers who participated in the CP-MGA271-06 study."
About Enoblituzumab
Enoblituzumab is an investigational anti-B7-H3 monoclonal antibody that incorporates an immunoglobulin G1 fragment crystallizable (Fc) domain designed to enhance Fcγ receptor-mediated antibody-dependent cellular cytotoxicity. B7-H3, a protein in the B7 family of immune regulator proteins, is widely expressed by a number of different tumor types and may play a key role in regulating the immune response to various types of cancer.
About Retifanlimab
Retifanlimab is an investigational anti-PD-1 monoclonal antibody being developed for use as monotherapy as well as in combination with other potential cancer therapeutics. Retifanlimab was licensed to Incyte Corporation in 2017 under a global collaboration and license agreement. MacroGenics retains the right to develop the molecule in combination with product candidates from its pipeline.
About Tebotelimab
Tebotelimab is an investigational, bispecific DART molecule designed to block PD-1 and lymphocyte-activation gene 3 (LAG-3) checkpoint molecules to sustain or restore the function of exhausted T cells.