Myeloid Therapeutics: Clinical Stage mRNA-Immunotherapy Company Inks $73 Million In Funding

By Noah Long • Jun 4, 2023

Myeloid Therapeutics – a clinical-stage mRNA-immunotherapy company – announced the completion of a $73 million financing led by Hatteras Investment Partners with participation from new investors ARCH Venture Partners and Moore Strategic Ventures. All existing investors, including Newpath Partners, 8VC, and Alexandria Venture Investments, also participated in the round.

The proceeds from the financing will support the continued clinical development of MT-101, Myeloid’s lead cell therapy program in Phase 1/2 for T cell lymphoma, and will accelerate the development of MT-302, a first-in-class TROP2-FcA mRNA-LNP product, into a Phase 1/2 study for TROP2-expressing tumors. And additional in vivo programming candidates are also advancing to the clinic.

MT-302: Emerging from the company’s proprietary ATAK CAR receptor library, Myeloid’s novel in vivo engineering platform specifically targets and activates myeloid cells to elicit broader anti-tumor adaptive immunity. And through this approach, Myeloid demonstrates that delivery of lipid-nanoparticles (LNPs) encapsulating mRNA results in uptake and selective expression by myeloid cells in vivo, leading to potent tumor killing in multiple cold tumor models.

The company’s lead in vivo program MT-302 is a TROP2-targeting in vivo CAR designed for expression within the myeloid compartment. And TROP2 is a tumor-associated antigen expressed widely on epithelial tumors, including some of the most difficult-to-treat cancers. The treatment with MT-302 has demonstrated monotherapy activity in a TROP2/TNBC model, confirming the potency of programmed myeloid cells in the absence of T cells. Myeloid believes that MT-302 has significant advantages over TROP2-ADC approaches through its ability to engage the full immune response. In 2023, Myeloid expects to initiate a Phase 1/2 clinical study with MT-302 for patients with TROP2-expressing tumors.

MT-101: MT-101 is the company’s first autologous CAR monocyte. And this candidate was derived from the Company’s proprietary ATAK platform and designed to harness the ability of myeloid cells to penetrate into tumors and promote broad anti-tumor activity. Plus MT-101 targets CD5, a surface receptor that is present in greater than 75% of peripheral T cell lymphomas. To create MT-101, the patient’s cells are engineered ex vivo with the mRNA-strand coding for the CAR. The engineered cells are delivered back to the patient within a vein-to-vein time of eight days. The ATAK CAR is proprietary to Myeloid and manufactured using the Company’s patented processes.

The IMAGINE study (NCT05138458) is a Phase 1/2, multicenter, open-label, first-in-human, multiple ascending dose study to evaluate MT-101 in patients with refractory or relapsed PTCL and CTCL. The dose-escalation portion of this study, conducted with and without conditioning therapy, is open and enrolling patients.

RetroT: Retrotransposons are genetic elements that replicate through reverse transcription of an RNA transposition intermediate. And retrotransposons contribute to structural changes and more importantly, to gene regulation. Myeloid’s RetroT technology relies on a single-strand mRNA to deliver genetic sequences and integration enzymes.

This breakthrough technology offers the potential to deliver gene-sized pieces of DNA into the genome in a virus-free manner. And the payload realizable with RetroT is larger than currently possible with all known existing gene editing technologies. As a result, the company’s RetroT platform holds the potential to significantly expand the type and scope of genetic errors that can be reversed in situ. In March 2022, Myeloid entered into an exclusive option and research collaboration agreement with Prime Medicine to develop and accelerate RetroT.

KEY QUOTES:

“Myeloid continues to make significant progress across all aspects of our business. We are pioneering the convergence of immunology and RNA science to build a clinical-stage portfolio of products, starting with the significant unmet needs of cancer patients. We are pleased that such high-quality investors have joined with us to accelerate this effort.”

— Daniel Getts, Ph.D., Chief Executive Officer of Myeloid

“Hatteras focuses on investments in cutting-edge companies that are disrupting the status quo and accelerating the pace of innovation. We are highly encouraged by the innovation, execution and clinical development progress demonstrated by Myeloid. We are proud to support this field-leading Company through its next phase of growth and are optimistic that these approaches will drive a meaningful clinical outcome for patients.”

— Clay B. Thorp, General Partner at Hatteras