We conclude that APR-246 is safe at predicted therapeutic plasma levels, shows a favorable pharmacokinetic profile, and can induce p53-dependent biologic effects in tumor cells in vivo.

Abstract Azacitidine treatment of myelodysplastic syndromes (MDSs) generally exacerbates thrombocytopenia during the first treatment cycles. A Study of Eltrombopag in Myelodysplastic Syndromes Receiving Azacitidine (SUPPORT), a phase 3, randomized, double-blind, placebo-controlled study, investigated the platelet supportive effects of eltrombopag given concomitantly with azacitidine. International Prognostic Scoring System intermediate-1, intermediate-2, or high-risk MDS patients with baseline platelets <75 × 109/L were randomized 1:1 to eltrombopag (start, 200 mg/d [East Asians, 100 mg/d], maximum, 300 mg/d [East Asians, 150 mg/d]) or placebo, plus azacitidine (75 mg/m2 subcutaneously once daily for 7 days every 28 days). The primary end point was the proportion of patients platelet transfusion-free during cycles 1 through 4 of azacitidine therapy. Based on planned interim analyses, an independent data monitoring committee recommended stopping the study prematurely because efficacy outcomes crossed the predefined futility threshold and for safety reasons. At termination, 28/179 (16%) eltrombopag and 55/177 (31%) placebo patients met the primary end point. Overall response (International Working Group criteria; complete, marrow, or partial response) occurred in 20% and 35% of eltrombopag and placebo patients, respectively, by investigator assessment. There was no difference in hematologic improvement in any cell lineage between the 2 arms. There was no improvement in overall or progression-free survival. Adverse events with ≥10% occurrence in the eltrombopag vs placebo arm were febrile neutropenia and diarrhea. Compared with azacitidine alone, eltrombopag plus azacitidine worsened platelet recovery, with lower response rates and a trend toward increased progression to acute myeloid leukemia. This trial was registered at www.clinicaltrials.gov as #NCT02158936.

In the last decade, Chimeric Antigen Receptor (CAR)-T cell therapy has emerged as a promising immunotherapeutic approach to fight cancers. This approach consists of genetically engineered immune cells expressing a surface receptor, called CAR, that specifically targets antigens expressed on the surface of tumor cells. In hematological malignancies like leukemias, myeloma, and non-Hodgkin B-cell lymphomas, adoptive CAR-T cell therapy has shown efficacy in treating chemotherapy refractory patients. However, the value of this therapy remains inconclusive in the context of solid tumors and is restrained by several obstacles including limited tumor trafficking and infiltration, the presence of an immunosuppressive tumor microenvironment, as well as adverse events associated with such therapy. Recently, CAR-Natural Killer (CAR-NK) and CAR-macrophages (CAR-M) were introduced as a complement/alternative to CAR-T cell therapy for solid tumors. CAR-NK cells could be a favorable substitute for CAR-T cells since they do not require HLA compatibility and have limited toxicity. Additionally, CAR-NK cells might be generated in large scale from several sources which would suggest them as promising off-the-shelf product. CAR-M immunotherapy with its capabilities of phagocytosis, tumor-antigen presentation, and broad tumor infiltration, is currently being investigated. Here, we discuss the emerging role of CAR-T, CAR-NK, and CAR-M cells in solid tumors. We also highlight the advantages and drawbacks of CAR-NK and CAR-M cells compared to CAR-T cells. Finally, we suggest prospective solutions such as potential combination therapies to enhance the efficacy of CAR-cells immunotherapy.

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