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

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.”