Myeloid Therapeutics brought a second in vivo cell therapy program into the clinic, once again taking aim at hard-to-treat solid tumors, the Cambridge, MA-based biotech exclusively told Endpoints News.
Myeloid is one of a handful of startups attempting to expand upon the success of cell therapies, which were first approved in the US in 2017 but rely on a costly and complicated ex vivo process to edit a patient’s cells.
The biotech is going a step further by advancing an in vivo therapy given via intravenous infusion and also treating patients with solid tumors. The first approved cell therapies are wildly successful against certain types of blood cancers, but less so in solid cancers. The startup is hoping its unique focus on the specific group of immune cells called myeloid cells will make the difference.
“The current state of play with T cell targeting technologies hasn’t gotten us to where we need to go,” Myeloid CEO Daniel Getts said in an interview. “If we want to overcome where we are today, we need novel approaches.”
Myeloid’s approach is to use messenger RNA and lipid nanoparticles — the same approach as some of the Covid-19 vaccines — to reach myeloid cells in the body. Getts called myeloid cells the orchestrators and first responders of the body’s immune response. The hope is these cells will take up Myeloid’s medicine after it’s infused and produce a particular protein with cancer-fighting effects. The company was founded in 2019 and last year raised a $73 million Series A2 round that included ARCH Venture Partners.
Myeloid’s newest clinical program, called MT-303, targets GPC3, a protein that is overexpressed in many liver cancer patients. Myeloid’s study is enrolling patients with the most prevalent type of liver cancer, called hepatocellular carcinoma, who also overexpress GPC3.
The biotech decided to advance the GPC3 program in December. At the same board meeting, Myeloid decided to terminate MT-101, a clinical-stage ex vivo program that engineered monocytes, a particular type of myeloid cells, Getts said. He added the decision was more driven by the cost of the ex vivo therapy and progress with its in vivo research rather than poor clinical data.
“It was expensive, and when we started to do more head-to-head comparisons with the in vivo approach, we’re actually getting better outcomes,” Getts said. “We can’t ignore the cost of goods. We have to be very cognizant of the pharma model.”
Myeloid also has a TROP2-targeting in vivo program called MT-302 that entered human testing last year. Myeloid’s leaders declined to provide a timeline for a clinical readout.
“We’re encouraged by the initial clinical data, both the initial tolerability and clinical activity that we’re seeing, and we’re continuing to dose escalate,” Myeloid’s chief medical officer Matthew Maurer said. “That program is still full bore ahead.”
The in vivo field has gotten more crowded in recent years, with several others approaching the clinic. Interius BioTherapeutics said earlier this month it received an OK in Australia to start a Phase 1 trial of INT2104, an in vivo CAR-T therapy. Umoja Biopharma also announced Wednesday morning it received an IND clearance for its in vivo CAR-T called UB-VV111. Other in vivo cell therapy startups still in the preclinical stages include Orna Therapeutics, Capstan Therapeutics and Asgard Therapeutics.
Getts noted a key difference between Myeloid and much of the field is his biotech’s focus on myeloid cells rather than T cells. Interius’ and Umoja’s lead programs also target blood cancers.
“These T cells, in my opinion, they’re not solving for the problem we’ve already got with other T-cell technologies,” Getts said, referencing challenges with the cold tumor microenvironment and getting T cells into the tumor.
Perhaps most similar to Myeloid, Carisma Therapeutics recently announced its own GPC3-targeted in vivo cell therapy that is partnered with Moderna. The Philadelphia-based biotech says it is targeting monocytes and macrophages, two types of myeloid cells. Carisma went public via reverse merger last year and has since struggled. It has discontinued drug programs and laid off staff. Getts noted that Carisma has also had issues with manufacturing and started its research with a narrower focus on macrophages.
“We’re just a very different company,” Getts said, “because we were an RNA company at our heart, and they were a macrophage company to begin with.”