Dublin, Ireland – 14^th 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 10-13^th).

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.”

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

Online publication: https://doi.org/10.1016/j.jtct.2022.10.029

Dublin, Ireland – 13^th June 2022 – Priothera, a late-clinical stage biotechnology company pioneering the development of its S1P receptor modulator compound, mocravimod, presented first clinical data on mocravimod (also known as KRP203) in hematological malignancies patients undergoing allogeneic hematopoietic stem cell transplant (HSCT) at the European Hematology Association (EHA) 2022 Congress, which was held in Vienna, Austria, June 9-12^th, 2022.

The oral presentation, which took place on 12^th June, was entitled A two-part, single- and two-arm randomized, open-label study to evaluate the safety, tolerability and pharmacokinetics of KRP203 in subjects with hematological malignancies undergoing allogeneic hematopoietic stem cell transplantation. The study showed that in the Phase 1b/2a study mocravimod was safe and well tolerated with promising overall survival.

Key take aways from the data presentation were:

• The study provided first ever human data of a S1P receptor modulator administered to patients undergoing allogeneic HSCT
• S1PR modulator class effects, such as bradycardia, were of no clinical concern
• Promising overall survival (OS) data
• Limited number of relapses, acute and chronic graft-versus-host disease (GVHD)
• Data supportive for conducting the planned MO-TRANS pivotal study to investigate efficacy (Relapse-free survival and OS) and GVHD in AML patients undergoing allogeneic HSCT

Priothera is initiating the pivotal MO-TRANS global Phase 2b/3 study in Europe, US and Japan, to assess the efficacy and safety of mocravimod as an adjunctive and maintenance therapy in adult AML patients undergoing allogeneic HSCT. The study is expected to start in the second half of 2022 and preliminary data from this study are expected by the end of 2024.

Florent Gros, Co-Founder and CEO of Priothera, said: “We are delighted to have been given the opportunity to present the full first human clinical data on mocravimod at the European Hematology Association Congress this year. Based on these results mocravimod has the potential to be a first-in-class therapy in maintaining graft-versus-leukemia responses while preventing graft-versus-host disease. This novel approach would provide a tremendous benefit to AML patients undergoing an allogeneic hematopoietic stem cell transplant. We are excited about mocravimod which leverages a well-described mode of action in a hematology/oncology setting and has been successfully used in autoimmune indications. Pre-clinical and clinical proof of concept studies have herewith demonstrated mocravimod’s ability to improve survival outcomes for this devastating disease. We look forward to advancing the global pivotal Phase 2/3 trial which is due to start in the second half of 2022.”  

Priothera’s abstract is available on EHA2022 Congress Abstract Book, here: https://journals.lww.com/hemasphere/Documents/EHA2022%20Congress%20Abstract%20Book.pdf

Dublin, Ireland – 31^st May 2022 – Priothera, a late-clinical stage biotechnology company pioneering the development of its S1P receptor modulator compound, mocravimod, today announces that the U.S. Food and Drug Administration (FDA) has granted Fast Track designation (FTD) for mocravimod in combination with allogeneic Hematopoietic Stem Cell Transplant (HSCT) for post remission therapy of Acute Myeloid Leukemia (AML) patients. FDA’s Fast Track designation is designed to facilitate the development and expedite the review of new drugs that are intended to treat serious or life-threatening diseases and that demonstrate the potential to address unmet medical needs.

Priothera is working to initiate the MO-TRANS global Phase 2b/3 study in Europe, US and Japan, to assess the efficacy and safety of mocravimod as an adjunctive and maintenance therapy in adult AML patients undergoing allogeneic HSCT. The MO-TRANS study is expected to start in the second half of 2022 and preliminary data from this study are expected by the end of 2024.

Karen Von Graevenitz, Head of Regulatory Affair at Priothera, commented ““The Fast Track designation grant for mocravimod in combination with allogeneic HSCT is an important milestoneand underlines the significant unmet need in AML patients undergoing HSCT, a serious disease where currently no available therapy exists. The designation means mocravimod will be eligible for expedited review and we will work closely with the US FDA to advance the global Phase 2/3 trial which is due to start in the second half of 2022.”