November 2022

Priothera – Positive mocravimod Phase 1b clinical data published in Transplantation and Cellular Therapy

Mocravimod is safe and well-tolerated in allogeneic hematopoietic cell transplantation (HCT) patients

Mocravimod significantly reduced circulating lymphocyte numbers and did not affect engraftment

Dublin, Ireland – 14th November 2022 – Priothera, a late-clinical stage biotechnology company pioneering the development of its S1P receptor modulator compound mocravimod, announces that positive data from the Phase 1b clinical trial evaluating mocravimod in allogeneic hematopoietic cell transplantation patients has been published in Transplantation and Cellular Therapy.

The study assessed the safety and tolerability of mocravimod in patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) for hematological malignancies. The secondary objectives were to determine the pharmacokinetic profile of mocravimod in this patient group as well as to assess GvHD-free, relapse-free survival at 6 months after last treatment.

The study found that mocravimod can safely be added to standard treatment regimens in patients with hematological malignancies requiring allo-HCT. CD4+ T cells were more sensitive to mocravimod treatment than CD8+ T cells. Mocravimod resulted in a significant reduction of circulating lymphocyte numbers and had no negative impact on engraftment and transplant outcomes.

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 HCT.

A global Phase 2b/3 study assessing the efficacy and safety of mocravimod as an adjunctive and maintenance therapy in acute myeloid leukemia (AML) patients undergoing allo-HCT is planned to start in the coming months. The trial design for this study will be published as an online abstract as part of the 2022 American Society of Hematology (ASH) conference (December 10-13th).

Florent Gros, Co-Founder and CEO of Priothera, said: “The positive Phase 1b data reinforce the potential for mocravimod to improve survival outcomes for patients with hematological malignancies requiring HCT. We’re looking forward to building upon this foundation with our upcoming pivotal Phase 2b/3 trial and advancing our lead asset towards its next significant milestones.”

Elisabeth Kueenburg, M.D., Chief Medical Officer at Priothera, commented: “Mocravimod’s mode of action has already been well established in autoimmune indications, and the Phase 1b trial shows that its potential also extends to hematology. We believe mocravimod has the potential to be a first-in-class therapy in maintaining graft-versus-leukemia responses, one of the most serious complications of allogeneic HCT, while preventing graft-versus-host disease.”

S. Dertschnig et al. Mocravimod, a selective S1PR modulator in allogeneic hematopoietic stem cell transplantation for malignancy, Transplantation and Cellular Therapy.

Online publication:

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 – commonly known as leukemias and lymphomas – led Priothera to further develop mocravimod for the treatment of blood cancers and the improvement of CAR-T cell therapy.

Mocravimod is being investigated as an adjunctive and maintenance treatment in a Phase 2b/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 intends to add quality life to patients.


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.

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Florent Gros, CEO

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