Cabaletta Bio now has the key fast track designation in hand as the biotech gears up for a Phase I/II trial in systemic lupus erythematosus (SLE).

The US Food and Drug Administration (FDA) granted a fast track designation for Cabaletta’s cell therapy CABA-201 in SLE, the company announced on May 1. Cabaletta plans to initiate an open-label Phase I/II trial of CABA-202 in SLE after earning the regulatory go-ahead.

With its planned Phase I/II trial, Cabaletta enters a crowded field of competitors vying to develop therapies for SLE. Most patients with SLE receive hydroxychloroquine and corticosteroids, with some patients receiving GSK’s antibody Benlysta (belimumab). Experts say the disease heterogeneity and variable standard of care makes it notoriously difficult to sensitively track disease progression in clinical trials.

While several companies are investigating antibodies and small molecules, cell therapies provide an alternate approach to treating SLE, where early studies have shown some success.  However, as the CAR-T cell therapy approach continues to gain steam, the field is turning toward broader questions surrounding patient access and supply. Meanwhile, the SLE space faces growing challenges in addressing the high racial disparities in treatment access and trial enrolment.

As Cabaletta navigates through these drug development challenges, the FDA fast track designation could provide a much-needed lift. The regulatory marker, which is designed for serious diseases with high unmet patient needs, will grant Cabaletta more frequent meetings and expedited reviews from the FDA.

Cabaletta’s CAR-T therapy in lupus

CABA-201 is a chimeric antigen receptor T cell (CAR-T) therapy targeting CD19, designed as a single-time infusion. The Phase I/II study will test CABA-201 in six patients with SLE and active lupus nephritis, as well as six patients with SLE and no renal involvement. There is no ClinicalTrials.gov listing for the trial as of publication.

SLE is an autoimmune disease that causes the body to attack its own tissues, and lupus nephritis is a type of kidney disease caused by SLE. An estimated 1.5 million people in the US and 5 million people worldwide have lupus, of which SLE is the most common type.