Background: Sabatolimab Sabatolimab: Sabatolimab (MBG453) is a novel immuno-myeloid therapy that binds to TIM-3 on immune cells, facilitating antileukemic immune activation and phagocytic killing of leukemic cells. Sabatolimab also binds to TIM-3 on leukemic cells, potentially impeding self-renewal of LSCs via inhibition of TIM3… is an immunotherapy targeting T-cell immunoglobulin domain and mucin domain-3 (TIM-3), an immuno-myeloid regulator expressed on immune cells and leukaemic stem cells stem cells: Cells in the body that develop into other cells. There are two main sources of stem cells. Embryonic stem cells come from human embryos and are used in medical research. Adult stem cells in the body repair and maintain the organ or tissue in which they are found. Blood-forming (hemapoietic) stem… . In this trial, we compared the efficacy and safety of sabatolimab plus hypomethylating agent with placebo placebo: A placebo is an inactive pill, liquid, or powder that has no treatment value. plus hypomethylating agents in previously untreated patients with higher-risk myelodysplastic syndromes myelodysplastic syndromes: (my-eh-lo-diss-PLASS-tik SIN-dromez) A group of disorders where the bone marrow does not work well, and the bone marrow cells fail to make enough healthy blood cells. Myelo refers to the bone marrow. Dysplastic means abnormal growth or development. People with MDS have low blood cell count for at… .
Methods: STIMULUS-MDS1 was a multicentre, randomised, double-blind, placebo-controlled, phase 2 study done at 54 investigational sites in 17 countries. Adult patients (aged ≥18 years) with intermediate-risk, high-risk, and very high-risk myelodysplastic syndromes (according to Revised International Prognostic Scoring System International Prognostic Scoring System: A system that turns patient data into a score. The score tells how quickly a myelodysplastic syndrome (MDS) case is progressing and helps predict what may happen with the patient's MDS in the future. Also called IPSS. criteria) who had not received previous treatment were included. Patients were randomly assigned (1:1) to intravenous sabatolimab (400 mg on day 8 and 22) or placebo plus a hypomethylating agent (intravenous decitabine decitabine: It works by reducing the amount of methylation in the body. Methylation is a process that acts like a switch to turn off or “silence” genes in certain cells. When these genes (called tumor suppressor genes) are turned off, MDS cells and cancer cells can grow freely. Decitabine is approved by the U… 20 mg/m2 on day 1-5 or intravenous or subcutaneous azacitidine azacitidine: It works by reducing the amount of methylation in the body. Methylation is a process that acts like a switch to turn off or “silence” genes in certain cells. When these genes (called tumor suppressor genes) are turned off, MDS cells and cancer cells can grow freely. Azacitidine is approved by the U… 75 mg/m2 on day 1-7 or day 1-5 and day 8 and 9) every 28 days until treatment discontinuation. The two primary endpoints were complete response rate and progression-free survival, assessed in the full analysis set, which included all randomly assigned patients. Complete response was analysed, as prespecified, 7 months after the last patient was randomly assigned. All other analyses presented, including progression-free survival, were done at the final data cutoff prespecified via a protocol protocol: An action plan that describes what will be done in a clinical trial and how it will be carried out. This plan is reviewed and approved by a committee at each place doing the clinical trial. This committee is known as the Institutional Review Board. amendment on Sept 2, 2021. Safety was assessed in in all patients who received at least one dose of study treatment. This study is registered with ClinicalTrials.gov, NCT03946670, and is ongoing.
Findings: Between July 29, 2019, and Aug 10, 2020, 127 patients were randomly assigned to sabatolimab plus a hypomethylating agent group (sabatolimab group; n=65) or placebo plus a hypomethylating agent (placebo group; n=62). The median age of participants was 73 years (IQR 69-77), of whom 86 (68%) of 127 patients were male and 77 (61%) were White. The primary endpoints were not met. Complete response (cutoff date of March 10, 2021) was achieved in 14 (22%; 95% CI 12·3-33·5) of 65 patients in the sabatolimab group vs 11 (18%; 9·2-29·5) of 62 patients in the placebo group (p=0·77). At the cutoff date of the final analysis (March 1, 2022), median follow-up for progression-free survival was 17·8 months (IQR 16·6-19·4) in the sabatolimab group and 19·2 months (17·7-22·3) in the placebo group, and the median progression-free survival was 11·1 months (95% CI 7·6-17·6) in the sabatolimab group vs 8·5 months (6·9-11·3) in the placebo group (hazard ratio 0·75 [95% CI 0·48-1·17]; p=0·1022). The most common adverse events of any grade were neutropenia neutropenia: (noo-truh-PEE-nee-uh) A condition in which there is a shortage of neutrophils in the bloodstream. Neutrophils are a type of white blood cell. This results in a low white blood cell count. (35 [56%] of 62 patients in the sabatolimab group vs 43 [68%] of 63 patients in the placebo group), thrombocytopenia thrombocytopenia: (throm-buh-sie-tuh-PEE-nee-uh) A condition in which there is a shortage of platelets in the bloodstream. This results in a low platelet count. Bleeding and bruising often occur with thrombocytopenia. (30 [48%] vs 32 [51%]), constipation (29 [47%] vs 24 [38%]), diarrhoea (27 [44%] vs 14 [22%]), anaemia (22 [35%] vs 34 [54%]), febrile neutropenia (22 [35%] vs 15 [24%]), and leukopenia (15 [24%] vs 20 [32%]). One patient developed a serious potential treatment-related immune-mediated adverse event in the sabatolimab group. There was one treatment-related death in the sabatolimab group due to pneumonitis.
Interpretation: The addition of sabatolimab to hypomethylating agents in this study did not result in a significant improvement in complete response rates or progression-free survival. Sabatolimab had a manageable safety in most patients with higher-risk myelodysplastic syndromes. A randomised phase 3 trial is ongoing to assess the potential benefit of sabatolimab plus azacitidine on overall survival in this setting.
Funding: Novartis Pharmaceuticals.