Cell-based Therapy to Improve Muscle Strength to Get Clinical Trial

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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MuSK-CAART | Myasthenia Gravis News | Illustration of a clinical trial

Cabaletta Bio has been cleared by the U.S. Food and Drug Administration (FDA) to start first-in-human clinical testing of MuSK-CAART, a cell-based therapy being developed to improve muscle strength in people with MuSK antibody-positive myasthenia gravis and help them in their activities of daily living.

“We look forward to initiating our first-in-human trial later this year,” David Chang, MD, Cabaletta’s chief medical officer, said in a press release.

The upcoming trial will consist of two phases, according to Cabaletta. In the first part, consecutively enrolled participants will be given increasing doses of the experimental therapy, with two participants per dose. The starting dose is 100 million cells, given via an infusion directly into the bloodstream.

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The purpose of the first phase is to identify the maximum tolerated dose, or the highest dose that can be safely given without unreasonable side effects. Based on those results, a single dose will be selected for testing in about 20 participants in the second phase.

The FDA also granted MuSK-CAAR fast track designation, which gives Cabaletta the opportunity to interact more frequently with the FDA during the development process. This designation is given to help hasten the development and review of treatments for serious conditions.

“We believe the FDA’s decision to grant Fast Track Designation highlights the need for a treatment capable of potentially delivering deep and durable responses for patients living with MuSK-associated MG,” Chang said.

MG is caused by self-reactive antibodies that interfere with the communication between nerve and muscle cells, ultimately leading to muscle weakness. Antibodies are immunological proteins made by immune cells called B-cells. In roughly 7.5% of patients, MG is specifically driven by antibodies that target a protein called muscle-specific kinase, or MuSK.

MuSK-CAART is a CAR T-cell therapy, a therapeutic technology first developed to treat blood cancers. T-cells are immune cells that are able to recognize a specific molecular pattern — for example, a piece of a virus — and kill cells that express that pattern, such as a virus-infected cell. A chimeric antigen receptor (CAR) is an artificially designed T-cell receptor that can direct these cells to kill a particular cell type of interest.

Specifically, MuSK-CAART contains T-cells with CARS that are designed to target and kill the B-cells that make MuSK-targeting antibodies.

Preclinical studies have suggested the therapy can effectively kill these disease-driving B-cells without impacting healthy B-cells, according to Cabaletta.

2021 Myasthenia Gravis Survey Results

BioNews Survey Infographic

Myasthenia Gravis News conducted a survey from Feb. 11-March 28 to gain greater insight into the characteristics of the MG community and disease management. Results of the survey have now been published. Click on the image to view the infographic, and click here to read the story.