March 2023

Priothera cleared to begin Japanese arm of pivotal Phase 3 study with mocravimod in patients with Acute Myeloid Leukemia undergoing allogeneic Hematopoietic Cell Transplant

Mocravimod is the only S1PR modulator being developed as an adjunctive and maintenance treatment for blood cancers

Dublin, Ireland – February 27th, 2023 – Priothera, a late-clinical stage biotechnology company pioneering the development of its S1P receptor modulator compound mocravimod, today announced that it received clearance from the Pharmaceuticals and Medical Devices Agency (PMDA) in Japan for the pivotal global MO-TRANS Phase 3 study evaluating mocravimod in Acute Myeloid Leukemia (AML) patients undergoing allogeneic hematopoietic cell transplant (HCT).

Elisabeth Kueenburg, M.D., Chief Medical Officer at Priothera, said: “We are grateful for the clearance from the PMDA to start our MO-TRANS Phase 3 study in Japan as we believe mocravimod has the potential to address a significant unmet need for Japanese patients with AML undergoing allogeneic HCT. We look forward to enrolling the first patients in several sites across Japan in the coming months.

Priothera is conducting the pivotal MO-TRANS study – now classified as a global Phase 3 trial following acceptance by regulatory authorities – in 15 countries, including the US, Japan, Israel, France, and in additional European, Asian and Latin American countries, to assess the efficacy and safety of mocravimod as an adjunctive and maintenance therapy in AML patients undergoing allogeneic HCT. The double-blind, placebo-controlled study assesses relapse-free and overall survival of two dose levels of mocravimod in comparison to placebo. Topline data from this study are expected in 2025.

Dr. Takanori Teshima, M.D., is the Principal Investigator in Japan for the MO-TRANS global Phase 3 trial. Dr. Teshima is Professor of Medicine in the Division of Hematology and Deputy-director of Hokkaido University Hospital. He serves as a president of the Japanese Society of Hematopoietic Cell Transplantation (JSHCT), an executive director of Japanese Society of Hematology (JSH) and Japan Society of Transfusion Medicine and Cell Therapy (JSTMCT).

Dr. Teshima, M.D., commented: “AML is the most common acute leukemia in Japan accounting for approximately 70% of all myeloid leukemias. Despite advances in the use of HCT in Japan, patients are still at risk of relapse with resulting poor prognosis. Any new treatment that can enhance the curative potential of this approach would offer a significant benefit to patients. I am therefore delighted that Japan will be part of the MO-TRANS global Phase 3 study investigating mocravimod as an innovative potential new adjunctive and maintenance therapy for patients with AML undergoing allogeneic Hematopoietic Cell Transplant.”

Mocravimod, a sphingosine 1 phosphate (S1P) receptor modulator which has been previously tested in multiple autoimmune indications, is being developed to enhance the curative potential of allogeneic HCT. Mocravimod has shown a clinically relevant benefit in an early clinical study in patients with hematologic malignancies undergoing allogeneic HCT.

Florent Gros, Co-Founder and CEO of Priothera, added: “Japan represents an important potential market for us and one we see as a priority as we advance the development of mocravimod in AML patients undergoing allogeneic HCT globally. With this clearance we anticipate a further uptake in patient enrollment in our MO-TRANS trial. We look forward to seeing topline results from MO-TRANS in 2025.” 

About mocravimod

Mocravimod (also known as KRP203) is a synthetic, sphingosine 1-phosphate receptor (S1PR) modulator. This novel investigational drug has been assessed in Phase 1 and Phase 2 trials for safety and tolerability, as well as for efficacy in several autoimmune indications. Promising data from a Phase 1b/2a clinical study in patients with hematological malignancies led Priothera to further develop mocravimod for the treatment of blood cancers and the improvement of CAR-T cell therapy.

Mocravimod is currently being investigated as an adjunctive and maintenance treatment in a Phase 3 study for patients with Acute Myeloid Leukemia (AML) receiving allogeneic hematopoietic cell transplantation (HCT). Allogeneic HCT is the only potentially curative approach for AML patients, but current treatments have unacceptably high mortality and morbidity rates.

Priothera leverages mocravimod’s unique mode of action to maintain the beneficial graft-versus leukemia (GVL) activity, while reducing tissue damage resulting from graft-versus-host disease (GVHD), both a consequence of allogeneic HCT. This novel treatment approach – mocravimod being the only S1PR modulator treating blood cancers – tackles a high unmet medical need and aims to improve patients’ quality of life.


About Priothera

Priothera is leading the way in developing orally applied sphingosine-1-phosphate (S1P) receptor modulators for the treatment of hematological malignancies and for the improvement of CAR-T cell therapies. S1P receptor modulators are known to largely reduce egress of T cells from lymphatic tissues. Unlike immunosuppressive drugs, mocravimod does not suppress the graft-versus-leukemia (GVL) benefits in patients receiving HCT while inhibiting graft-versus-host-disease (GVHD).

Priothera was founded in 2020 by an experienced team of drug development experts and is headquartered in Dublin, Ireland, and with a subsidiary in Saint-Louis, France. The Company is backed by international founding investors Fountain Healthcare Partners (Dublin, Ireland), funds managed by Tekla Capital Management, LLC (Boston, Massachusetts), HealthCap (Stockholm, Sweden), EarlyBird Venture Capital (Berlin, Germany), as well as non-dilutive financing in the form of loans from the European Investment Bank under its Venture Debt Instrument and Bpifrance (Grand Est Bpifrance) in the form of a R&D innovation loan.

For more information please visit: or follow Priothera on LinkedIn


Florent Gros, CEO

MEDiSTRAVA Consulting
Sylvie Berrebi, Sandi Greenwood, Frazer Hall
T: +44 (0) 203 928 6900