Avelumab in Patients With Gestational Trophoblastic Tumors With Resistance to Single-Agent Chemotherapy: Cohort A of the TROPHIMMUN Phase II Trial
Benoît You, Pierre‐Adrien Bolze, Jean‐Pierre Lotz, Jérôme Massardier, Laurence Gladieff, Florence Joly, Touria Hajri, Delphine Maucort‐Boulch, Sylvie Bin, Pascal Rousset, Mojgan Devouassoux‐Shisheboran, Adeline Roux, Marine Alves-Ferreira, D. Grazziotin-Soares, Carole Langlois‐Jacques, Catherine Mercier, Laurent Villeneuve, Gilles Freyer, François Golfier
Abstract
PURPOSE: Women with gestational trophoblastic tumors (GTT) resistant to single-agent chemotherapy receive alternative chemotherapy regimens, which, although effective, cause considerable toxicity. All GTT subtypes express programmed death-ligand 1 (PD-L1), and natural killer (NK) cells are involved in trophoblast immunosurveillance. Avelumab (anti-PD-L1) induces NK cell-mediated cytotoxicity. The TROPHIMMUN trial assessed avelumab in women with chemotherapy-resistant GTT. METHODS: In this phase II multicenter trial (ClinicalTrials.gov identifier: NCT03135769), women with GTT who experienced disease progression after single-agent chemotherapy received avelumab 10 mg/kg intravenously every 2 weeks until human chorionic gonadotropin (hCG) normalization, followed by 3 consolidation cycles. Rate of hCG normalization was the primary endpoint (2-step Simon design). RESULTS: Between December 2016 and September 2018, 15 patients were treated. Median age was 34 years; disease stage was I or III in 53.3% and 46.7% of women, respectively; and International Federation of Gynecology and Obstetrics (FIGO) score was 0-4 in 33.3%, 5-6 in 46.7%, and ≥ 7 in 20% of patients. Prior treatment included methotrexate (100%) and actinomycin D (7%). Median follow-up was 25 months, and median number of avelumab cycles was 8 (range, 2-11). Grade 1-2 treatment-related adverse events occurred in 93% of patients, most commonly (≥ 25%) fatigue (33.3%), nausea/vomiting (33.3%), and infusion-related reaction (26.7%). One patient had grade 3 uterine bleeding (treatment unrelated). Eight patients (53.3%) had hCG normalization after a median of 9 avelumab cycles; none subsequently relapsed. Probability of normalization was not associated with disease stage, FIGO score, or baseline hCG. One patient subsequently had a healthy pregnancy. In avelumab-resistant patients (46.7%), hCG was normalized with actinomycin D (42.3%) or combination chemotherapy/surgery (57.1%). CONCLUSION: In patients with single-agent chemotherapy-resistant GTT, avelumab had a favorable safety profile and cured approximately 50% of patients. Avelumab could be a new therapeutic option, particularly in patients who would otherwise receive combination chemotherapy.