8-K: Vor Bio Announces Positive Clinical Data for Trem-cel and New Preclinical Asset

Vor Biopharma reports promising clinical data from its Phase 1/2 trial of trem-cel combined with Mylotarg, demonstrating reliable engraftment, shielding, and early signs of patient benefit, along with the introduction of a new preclinical asset, VADC45.

Summary

• Vor Biopharma has released updated clinical data from its Phase 1/2 VBP101 study, which involves patients with relapsed/refractory AML receiving trem-cel followed by Mylotarg.
• The study included 18 patients treated with trem-cel, with 10 of those receiving Mylotarg as of the July 19, 2024 data cut-off.
• The data showed 100% of patients achieved primary neutrophil engraftment with a median of 9 days, and robust platelet recovery with a median of 16.5 days.
• High CD33 editing efficiency was observed, with a median of 89% and a range of 71-94%, and full myeloid chimerism was achieved by Day 28.
• The study demonstrated shielding of the blood system, with maintained neutrophil and platelet counts across multiple Mylotarg doses.
• The therapeutic index for Mylotarg was broadened, with drug exposure consistent with labeled doses and maximal concentrations well below the known toxic range.
• Early evidence suggests patient benefit, with only four patients relapsing, two before Mylotarg treatment and two after, both with TP53 mutations.
• Vor Bio plans to explore a registrational trial for trem-cel and Mylotarg while continuing to develop other therapies like VCAR33ALLO and VADC45.
• The VBP301 study for VCAR33ALLO is ongoing, with encouraging in vivo CAR-T expansion data from three patients at the lowest dose of 1 x 106 CAR+ cells/kg.
• A new preclinical asset, VADC45, targeting the CD45 protein, has been announced with potential applications in oncology, gene therapy, and autoimmune disorders.

Sentiment

Score: 8

Explanation: The document presents very positive clinical data, a new preclinical asset, and a clear path forward, indicating strong potential for the company's technology. The only negative is the relapse of two patients with TP53 mutations, but overall the sentiment is very positive.

Positives

• The clinical data shows reliable engraftment and robust platelet recovery.
• High CD33 editing efficiency indicates the effectiveness of the gene editing technology.
• The shielding of the blood system allows for the use of Mylotarg without significant toxicity.
• The broadened therapeutic index for Mylotarg suggests improved safety and efficacy.
• Early evidence of patient benefit indicates the potential for improved outcomes.
• The VCAR33ALLO program shows encouraging in vivo CAR-T expansion data.
• The new preclinical asset, VADC45, has potential in multiple therapeutic areas.

Negatives

• Two patients relapsed following Mylotarg treatment, both with TP53 mutations, indicating a potential limitation of the therapy in this specific patient subgroup.
• The data is from a Phase 1/2 study, and further trials are needed to confirm these results.

Risks

• The success of the clinical trials is not guaranteed, and results may not be consistent in larger studies.
• Regulatory approvals for the therapies are not certain.
• The company's ability to manufacture the therapies at scale is a risk.
• The company's financial stability and ability to fund operations is a risk.
• The company may not achieve the plans, intentions, or expectations disclosed in forward-looking statements.

Future Outlook

Vor Bio plans to explore a registrational trial for trem-cel and Mylotarg, continue enrolling patients in the VCAR33ALLO study, and progress IND-enabling studies for VADC45, with the aim of changing the standard of care for patients with blood cancers.

Management Comments

• Dr. Eyal Attar, Vor Bio's Chief Medical Officer, stated that they are encouraged by the data and the potential benefit that trem-cel in combination with Mylotarg may offer to patients.
• Guenther Koehne, MD, PhD, an investigator on the VBP101 study, expressed support for the safety of the approach and looks forward to treating more patients on the trial.

Industry Context

This announcement is significant in the context of the broader industry trend towards developing targeted therapies for blood cancers, particularly in the post-transplant setting. The use of gene editing and cell therapies is gaining traction, and Vor Bio's approach of shielding stem cells to enable more aggressive treatments is innovative.

Comparison to Industry Standards

• The reported 100% neutrophil engraftment and median of 9 days is comparable to or better than standard allogeneic hematopoietic stem cell transplant (HSCT) outcomes, where engraftment can be variable and take longer.
• The median platelet recovery of 16.5 days is also within the expected range for HSCT, but the robust nature of the recovery is a positive sign.
• The CD33 editing efficiency of 89% is high, indicating a successful gene editing process, which is a key differentiator for Vor Bio's approach compared to traditional transplants.
• The broadened therapeutic index for Mylotarg, with drug exposure consistent with labeled doses and maximal concentrations well below the known toxic range, is a significant improvement over standard Mylotarg use, which is often limited by toxicity.
• The early evidence of patient benefit, with a low relapse rate compared to published high-risk AML comparators, suggests a potential advantage over standard treatments, such as those described in Araki et al. JCO 2016 and Jentzsch et al. Blood Cancer Journal 2022.
• The in vivo CAR-T expansion data for VCAR33ALLO is encouraging, as it suggests the potential for this therapy to be effective in the post-transplant setting, similar to the autologous CAR-T results reported by Shah et al. ASH 2023.

Stakeholder Impact

• Shareholders will likely react positively to the promising clinical data and new asset announcement.
• Patients with relapsed/refractory AML may benefit from the potential new treatment options.
• Employees may be motivated by the positive progress and potential impact of their work.
• The company's success could lead to increased demand for its services and products from suppliers and partners.

Next Steps

• Vor Bio plans to explore a registrational trial for trem-cel and Mylotarg.
• The company will continue enrolling patients in the VBP301 study for VCAR33ALLO.
• Vor Bio will progress IND-enabling studies for VADC45 to enable future Phase 1 studies.
• The company plans to approach the FDA to discuss a pivotal trial design for trem-cel + Mylotarg by around year end.

Key Dates

Keywords

Trem-cel, Mylotarg, VCAR33ALLO, VADC45, AML, CD33, CD45, Hematopoietic Stem Cell Transplant, Gene Therapy, CAR-T, Antibody Drug Conjugate, Oncology