Atara Biotherapeutics, Inc. (Nasdaq: ATRA), a leader in T-cell immunotherapy, leveraging its novel allogeneic Epstein-Barr virus (EBV) T-cell platform to develop transformative therapies for patients with cancer and autoimmune diseases, today announced the U.S. Food and Drug Administration (FDA) has cleared an Investigational New Drug (IND) application for ATA3219, an allogeneic, anti-CD19 chimeric antigen receptor (CAR) T-cell monotherapy for the treatment of systemic lupus erythematosus (SLE) with kidney involvement (lupus nephritis [LN]).

“Expanding upon an extensive clinical experience encompassing the treatment of over 600 patients using our allogeneic T-cell platform in both oncology and autoimmune diseases, we are excited to clinically evaluate the potential of our differentiated allogeneic CAR T-cell approach. We are eager to address the significant unmet need in lupus nephritis as we initiate our Phase 1 trial,” said Pascal Touchon, President and Chief Executive Officer of Atara. “We look forward to bringing the promise and accessibility of a potentially curative off-the-shelf cell therapy option to patients with severe autoimmune diseases, potentially eliminating the burdens of autologous CAR T therapies like costly infrastructure and treatment delays.”

The multi-center, Phase 1, open-label, single-arm, dose-escalation study will evaluate the safety and preliminary efficacy of ATA3219 in subjects with LN. Subjects will receive lymphodepletion treatment followed by ATA3219 at a dose of 40, 80, or 160 x 10⁶ CAR+ T cells. ATA3219 is designed to be given as a one-time infusion and followed for safety and efficacy. Each dose level is designed to enroll 3-6 patients, with the first subject expected to be enrolled in the second half of 2024.

“Existing therapeutic agents for lupus nephritis yield suboptimal responses and have limitations due to their requirement for ongoing administration, susceptibility to treatment failures, and limited accessibility to inflamed tissues resulting in incomplete depletion of B cells,” said Rajani Dinavahi, Chief Medical Officer at Atara. “CAR T cells can naturally infiltrate deep into target tissues to mediate B-cell depletion and produce durable responses. Building on the encouraging academic data in lupus nephritis with autologous CD19 CAR T, ATA3219 is an off-the-shelf therapy that could significantly reduce constraints for patients and physicians like leukapheresis and long waiting times, therefore potentially improving access to a large population of patients.”

Proof of concept for a CD19 CAR T approach in autoimmune disease was first demonstrated in early academic results from an investigator-sponsored study showing 100% (8/8) of LN patients rapidly attaining drug-free, durable remission with an autologous CD19-targeted CAR T therapy. The therapy eliminated the pathogenic, autoreactive B cells and allowed healthy B cells to return after treatment, enabling the patients’ immune system to function normally again with associated improvement of clinical symptoms.¹ These early proof of concept clinical data with CD19 targeted CAR T support further development of CAR T for LN with differentiated and off-the-shelf allogeneic approaches.

The ATA3219 IND submission included in vitro data reflecting the CD19 antigen-specific functional activity of ATA3219 and CAR-mediated activity against B cells from SLE patients. ATA3219 led to robust CD19-specific B-cell depletion compared to controls.

LN is a serious and most common complication of SLE, a chronic multisystem autoimmune disease. The prevalence of SLE in the U.S. is 73 per 100,000 people, afflicting more than 200,000 U.S. patients alone, and occurs in women much more commonly than men. Up to 60% of adult patients with SLE develop renal disease during the course of their illness, and up to 70% of patients with LN are refractory to standard immunosuppressive therapies. Despite recent advances in treatment strategies, the response rate using existing therapies remains low, with significant risk of long-term morbidity and mortality associated with refractory LN.