Use of CAR-Transduced Natural Killer Cells in CD19-Positive Lymphoid Tumors.

BACKGROUND: Anti-CD19 chimeric antigen receptor (CAR) T-cell therapy has shown remarkable clinical efficacy in B-cell cancers. However, CAR T cells can induce substantial toxic effects, and the manufacture of the cells is complex. Natural killer (NK) cells that have been modified to express an anti-CD19 CAR have the potential to overcome these limitations. METHODS: In this phase 1 and 2 trial, we administered HLA-mismatched anti-CD19 CAR-NK cells derived from cord blood to 11 patients with relapsed or refractory CD19-positive cancers (non-Hodgkin's lymphoma or chronic lymphocytic leukemia [CLL]). NK cells were transduced with a retroviral vector expressing genes that encode anti-CD19 CAR, interleukin-15, and inducible caspase 9 as a safety switch. The cells were expanded ex vivo and administered in a single infusion at one of three doses (1×105, 1×106, or 1×107 CAR-NK cells per kilogram of body weight) after lymphodepleting chemotherapy. RESULTS: The administration of CAR-NK cells was not associated with the development of cytokine release syndrome, neurotoxicity, or graft-versus-host disease, and there was no increase in the levels of inflammatory cytokines, including interleukin-6, over baseline. The maximum tolerated dose was not reached. Of the 11 patients who were treated, 8 (73%) had a response; of these patients, 7 (4 with lymphoma and 3 with CLL) had a complete remission, and 1 had remission of the Richter's transformation component but had persistent CLL. Responses were rapid and seen within 30 days after infusion at all dose levels. The infused CAR-NK cells expanded and persisted at low levels for at least 12 months. CONCLUSIONS: Among 11 patients with relapsed or refractory CD19-positive cancers, a majority had a response to treatment with CAR-NK cells without the development of major toxic effects. (Funded by the M.D. Anderson Cancer Center CLL and Lymphoma Moonshot and the National Institutes of Health; ClinicalTrials.gov number, NCT03056339.).

A prospective phase 2 clinical trial of a C5a complement inhibitor for acute GVHD with lower GI tract involvement.

Involvement of lower gastrointestinal tract (LGI) occurs in 60% of patients with graft-versus-host-disease (GVHD). Complement components C3 and C5 are involved in GVHD pathogenesis. In this phase 2a study, we evaluated the safety and efficacy of ALXN1007, a monoclonal antibody against C5a, in patients with newly diagnosed LGI acute GVHD receiving concomitant corticosteroid. Twenty-five patients were enrolled; one was excluded from the efficacy analysis based upon negative biopsy. Most patients (16/25, 64%) had acute leukemia; 52% (13/25) had an HLA-matched unrelated donor; and 68% (17/25) received myeloablative conditioning. Half the patients (12/24) had a high biomarker profile, Ann Arbor score 3; 42% (10/24) had high-risk GVHD per Minnesota classification. Day-28 overall response was 58% (13/24 complete response, 1/24 partial response), and 63% by Day-56 (all complete responses). Day-28 overall response was 50% (5/10) in Minnesota high-risk and 42% (5/12) in high-risk Ann Arbor patients, increasing to 58% (7/12) by Day-56. Non-relapse mortality at 6-months was 24% (95% CI 11-53). The most common treatment-related adverse event was infection (6/25, 24%). Neither baseline complement levels (except for C5), activity, nor inhibition of C5a with ALXN1007 correlated with GVHD severity or responses. Further studies are needed to evaluate the role of complement inhibition in GVHD treatment.

Randomized phase II trial of extracorporeal phototherapy and steroids vs. steroids alone for newly diagnosed acute GVHD.

Steroids remain the initial therapy for acute graft-vs.-host disease (AGVHD). Strategies to improve response and minimize steroid exposure are needed. We report results of a randomized, adaptive, Bayesian-designed, phase II trial of prednisone with or without extracorporeal photopheresis (ECP) as an initial therapy for patients with newly diagnosed AGVHD. The primary endpoint was success at day 56 defined as: alive, in remission, achieving AGVHD response without additional therapy, and on <1 mg/kg at day 28 and <0.5 mg/kg on day 56 of steroids. Eighty-one patients were randomized to the ECP arm (n = 51) or steroids alone (n = 30). Median age was 54 years (range: 17-75); 90% had grade II AGVHD and 10% had grades III and IV AGVHD, with skin (85%), upper (22%)/lower (22%) gastrointestinal, and liver (10%) involvement. The ECP arm had a higher probability of success (0.815) and exceeded the predefined threshold for determining the investigational arm promising. ECP was potentially more beneficial than steroids-alone in skin-only AGVHD (response rate: 72% vs. 57%, respectively) than for visceral-organ AGVHD (47% vs. 43%, respectively). The addition of ECP to steroids may result in higher GVHD response as initial therapy for AGVHD, especially for patients with skin-only involvement.