The EURE-CART project as a prototype model for CAR T-cell immunotherapy in Europe

CAR T-cell therapy in autoimmune diseases

Despite the tremendous progress in the clinical management of autoimmune diseases, many patients do not respond to the currently used treatments. Autoreactive B cells play a key role in the pathogenesis of autoimmune diseases, such as systemic lupus erythematosus, rheumatoid arthritis, and multiple sclerosis. B-cell-depleting monoclonal antibodies, such as rituximab, have poor therapeutic efficacy in autoimmune diseases, mainly due to the persistence of autoreactive B cells in lymphatic organs and inflamed tissues. The adoptive transfer of T cells engineered to target tumour cells via chimeric antigen receptors (CARs) has emerged as an effective treatment modality in B-cell malignancies. In the last 2 years treatment with autologous CAR T cells directed against the CD19 antigen has been introduced in therapy of autoimmune disease. CD19 CAR T cells induced a rapid and sustained depletion of circulating B cells, as well as in a complete clinical and serological remission of refractory systemic lupus erythematosus and dermatomyositis. In this paper, we discuss the evolving strategies for targeting autoreactive B cells via CAR T cells, which might be used for targeted therapy in autoimmune diseases.

Anti-CD19 CAR T cell therapy for refractory systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a life-threatening autoimmune disease characterized by adaptive immune system activation, formation of double-stranded DNA autoantibodies and organ inflammation. Five patients with SLE (four women and one man) with a median (range) age of 22 (6) years, median (range) disease duration of 4 (8) years and active disease (median (range) SLE disease activity index Systemic Lupus Erythematosus Disease Activity Index: 16 (8)) refractory to several immunosuppressive drug treatments were enrolled in a compassionate-use chimeric antigen receptor (CAR) T cell program. Autologous T cells from patients with SLE were transduced with a lentiviral anti-CD19 CAR vector, expanded and reinfused at a dose of 1 × 10⁶ CAR T cells per kg body weight into the patients after lymphodepletion with fludarabine and cyclophosphamide. CAR T cells expanded in vivo, led to deep depletion of B cells, improvement of clinical symptoms and normalization of laboratory parameters including seroconversion of anti-double-stranded DNA antibodies. Remission of SLE according to DORIS criteria was achieved in all five patients after 3 months and the median (range) Systemic Lupus Erythematosus Disease Activity Index score after 3 months was 0 (2). Drug-free remission was maintained during longer follow-up (median (range) of 8 (12) months after CAR T cell administration) and even after the reappearance of B cells, which was observed after a mean (±s.d.) of 110 ± 32 d after CAR T cell treatment. Reappearing B cells were naïve and showed non-class-switched B cell receptors. CAR T cell treatment was well tolerated with only mild cytokine-release syndrome. These data suggest that CD19 CAR T cell transfer is feasible, tolerable and highly effective in SLE.

New targets and technologies for CAR-T cells

PURPOSE OF REVIEW

Immunotherapy with gene-engineered chimeric antigen receptor (CAR)-T cells has curative potential in advanced malignancies and undergoes a surging preclinical and clinical development. Here, we present a selection of new targets and technologies that illustrate the progress that is being made with the aspiration to make CAR-T cell therapy a universally applicable and effective treatment in cancer medicine.

RECENT FINDINGS

There is a rich pipeline of new target antigens for CAR-T cells in hematology and oncology that are rated based on uniformity but also stability of expression on tumor cells under therapeutic pressure. New technologies in CAR-T cell engineering are directed at neutralizing inhibitory ligands and factors in the tumor microenvironment, preventing CAR-T cell exhaustion and enhancing selectivity for tumor cells with 'smart' CAR designs. The manufacture of CAR-T cells using virus-free protocols is anticipated to reduce supply-chain complexity and to improve patient access.

SUMMARY

CD19 CAR-T cell therapy is an approved treatment for B-cell leukemia and -lymphoma and considering the current 'target and technology' pipeline, we anticipate that additional CAR-T cell products will accomplish their 'breakthrough' and clinical proof-of-concept in other indications in hematology and in oncology. Technologies to enhance therapeutic index and facilitate manufacturing will be key for assuring availability and accessibility of CAR-T cell products and their implementation into routine clinical practice.