PureTech Founded Entity Vor Bio Announces New Clinical Data Validating Approach of Using Shielded Transplants to Deliver Targeted Therapies

Trem-cel + Mylotarg demonstrated engraftment, shielding, broadened therapeutic window, and patient benefit

VCAR33^ALLO demonstrates encouraging biomarker data at lowest dose

New asset VADC45 with significant potential opportunities across oncology, gene therapy, and autoimmune disorders

PureTech Health plc (Nasdaq: PRTC, LSE: PRTC) ("PureTech" or the "Company"), a clinical-stage biotherapeutics company dedicated to changing the lives of patients with devastating diseases, noted that its Founded Entity, Vor Bio (Nasdaq: VOR), a clinical-stage cell and genome engineering company, announced new clinical data from its ongoing Phase 1/2 VBP101 study of patients with relapsed/refractory AML receiving trem-cel followed by Mylotarg™. The data demonstrated reliable engraftment, shielding from Mylotarg on-target toxicity, a broadened Mylotarg therapeutic window, and early evidence of patient benefit.

The full text of the announcement from Vor is as follows:

New Clinical Data Validates Vor Bio’s Approach of Using Shielded Transplants to Deliver Targeted Therapies

Trem-cel + Mylotarg demonstrated engraftment, shielding, broadened therapeutic window, and patient benefit

VCAR33^ALLO demonstrates encouraging biomarker data at lowest dose

New asset VADC45 with significant potential opportunities across oncology, gene therapy, and autoimmune disorders

CAMBRIDGE, Mass., Sept. 05, 2024 -- Vor Bio (Nasdaq: VOR), a clinical-stage cell and genome engineering company, today announced new clinical data from its ongoing Phase 1/2 VBP101 study of patients with relapsed/refractory AML receiving trem-cel followed by Mylotarg™. The data demonstrated reliable engraftment, shielding from Mylotarg on-target toxicity, a broadened Mylotarg therapeutic window, and early evidence of patient benefit.

“We are encouraged by this data and the potential benefit that trem-cel in combination with Mylotarg may offer to patients in a disease that has extremely poor outcomes even after transplant,” said Dr. Eyal Attar, Vor Bio’s Chief Medical Officer. “With this data, we plan to explore a registrational trial while we continue to pursue other synergistic opportunities for Vor Bio’s platform such as VCAR33^ALLO and VADC45.”  

The data released today included 18 patients treated with trem-cel of which ten had received Mylotarg as of the data cut-off date of July 19, 2024. The data demonstrated:

• Reliable engraftment, with 100% of patients achieving primary neutrophil engraftment​ (median 9 days) and robust platelet recovery (median 16.5 days)​. High CD33 editing efficiency (median 89%, range 71-94%)​ and full myeloid chimerism ​at Day 28.
• Shielding of the blood system, with maintained neutrophil and platelet counts across multiple Mylotarg doses of 0.5, 1, and 2 mg/m².
• Broadened therapeutic index for Mylotarg with drug exposure represented by AUC which is related to efficacy, consistent with labeled Mylotarg doses, and with maximal concentrations, measured by C_max and related to veno-occlusive disease, well below known toxic range.
• Early evidence suggesting patient benefit as measured by relapse-free survival when compared to published high-risk AML comparators¹.

“All the hope I had in the safety of this approach has been supported by the data from this trial thus far,” said Guenther Koehne, MD, PhD, an investigator on the VBP101 study and Deputy Director and Chief of Blood & Marrow Transplant and Hematologic Oncology at Miami Cancer Institute of Baptist Health South Florida. “I look forward to treating my next patients at high risk of relapse on this trial as their outcomes are otherwise limited with standard transplants.”

Vor Bio plans to approach the U.S. Food & Drug Administration to discuss a pivotal trial design for trem-cel + Mylotarg by around year end.

Continued progress with VCAR33^ALLO

• VCAR33^ALLO represents another potentially significant synergistic treatment option after trem-cel.
• The VBP301 study continues enrolling patients with initial focus on relapsed/refractory AML post-transplant.
• Vor Bio is encouraged by in vivo CAR-T expansion data from three patients treated to date, all at the lowest dose of 1 x 10⁶ CAR+ cells/kg.

Vor Bio announced today, a new preclinical asset, VADC45, which has a number of potential opportunities in oncology, gene therapy, and autoimmune disorders.

• VADC45 is an ADC that targets the CD45 protein. CD45 is a well-validated target for a wide variety of blood cancers with clinical proof of concept. The linker-payload used in VADC45 is also clinically validated.
• VADC45 has the potential to treat a number of diseases, including treatment of hematologic malignancies, as a targeted conditioning agent for gene therapies such as for sickle cell disease, holistic immune reset for autoimmune disorders, and for Vor Bio’s approach of combining this asset with epitope modification of CD45 to shield healthy stem cells.
• Vor Bio already has robust preclinical data for VADC45 and is progressing IND-enabling studies to enable future Phase 1 studies.

About Vor Bio
Vor Bio is a clinical-stage cell and genome engineering company that aims to change the standard of care for patients with blood cancers by engineering hematopoietic stem cells to enable targeted therapies post-transplant. For more information, visit: www.vorbio.com.