Posttraumatic stress disorder (PTSD) is a prevalent mental health condition with substantial impact on daily functioning that lacks sufficient treatment options. In Europe, lifetime PTSD prevalence ranges from 0.56% to 6.67% in the general population. MDMA-assisted therapy (MDMA-AT) has proven to be both efficacious and safe among participants with severe PTSD in clinical trials that primarily focused on U.S. samples. These results warrant further investigation among diverse populations for wider dissemination. A multi-site open-label Phase 2 study in up to 40 participants to explore the safety and effectiveness of MDMA-AT in at least severe PTSD is currently ongoing in the Czech Republic, Netherlands, Norway, Germany, United Kingdom, Portugal and Spain. The treatment protocol consists of 3 preparatory sessions, and 2 monthly 8-hour experimental sessions using an 80 or 120 mg MDMA dose and supplemental 40 or 60 mg MDMA half-dose followed by 3 integrative sessions each. The Phase 2 study provides the opportunity for clinical supervision of new therapy teams, cross-cultural validation of an updated Clinician Administered PTSD Scale for DSM-5 (CAPS-5) and serves as a lead-in to a larger Phase 3 study in Europe anticipated to start in the fall of 2022. This randomized, double-blind, placebo-controlled, multicenter Phase 3 Study will investigate the efficacy and safety of MDMA-AT compared to therapy plus placebo for the treatment of at least moderate PTSD. During the session preliminary findings of the Phase-2 trial and design of the Phase-3 trial will be presented.Corine de Boer, M.D., Ph.D. is the Chief Medical Officer at MAPS Public Benefit Corporation. She received her MD from Radboud University in Nijmegen, the Netherlands and completed residency and fellowship training in pediatrics and pediatric nephrology. Her Ph.D. was focused on peritoneal dialysis in children, and she joined the academic staff at the Radboud University after completing her training. Before moving to the United States in 2000, she worked as a Pediatrician in the largest inner-city hospital (OLVG) in Amsterdam where she was responsible for in- and outpatient care in a multi-racial patient population. For the last 20+years, she has contributed to the development of meningococcal and hepatitis vaccines during her tenure at GSK vaccines (formerly Novartis Vaccines and Chiron Corporation) and Dynavax prior to starting her own consulting company where she provided strategic advice and support for a variety of clients working on biologics, small molecule/polymer therapeutics and vaccines. She formally joined MPBC in early 2020 after assisting them previously in the development of the Pediatric Plans for MDMA-AT. The opportunity that psychedelics provide in the treatment of PTSD and other indications is an exciting scientific field where she feels honored to play a small part in.