NEJM original articles

Background. Exagamglogene autotemcel (exa-cel) is a cell therapy in which autologous CD34+ hematopoietic cells are engineered through ex vivo clustered regularly interspaced short palindromic repeats-Cas9 editing of the erythroid-specific enhancer region of BCL11A to express fetal hemoglobin. In phase 3 studies involving participants 12 to 35 years of age with sickle cell disease or transfusion-dependent β-thalassemia, exa-cel eliminated vaso-occlusive crises and the need for red-cell transfusions.

Methods. In two ongoing, phase 3, open-label, single-group studies, we evaluated exa-cel in children 5 to 11 years of age with transfusion-dependent β-thalassemia or sickle cell disease. Before exa-cel infusion, participants underwent myeloablative conditioning with pharmacokinetically dose-adjusted busulfan. The primary end points were transfusion independence for at least 12 consecutive months in children with transfusion-dependent β-thalassemia and freedom from severe vaso-occlusive crises for at least 12 consecutive months in children with sickle cell disease.

Results. A total of 15 children with transfusion-dependent β-thalassemia and 11 with sickle cell disease received exa-cel; median follow-up was 16.0 months (range, 2.2 to 32.1) and 16.9 months (range, 7.6 to 33.1), respectively. Of 8 children with transfusion-dependent β-thalassemia who were followed to at least 16 months, 8 were transfusion independent; the status of the remaining 7 was not yet evaluable. Of 8 children with sickle cell disease who were followed to at least 16 months, 8 were free of vaso-occlusive crises; the status of the remaining 3 was not yet evaluable. All the children had at least one grade 3 or 4 adverse event; 2 children with transfusion-dependent β-thalassemia had severe veno-occlusive liver disease that was assessed as being related to busulfan conditioning, 1 of whom died.

Conclusions. Exa-cel therapy resulted in transfusion independence or freedom from severe vaso-occlusive crises in participants with transfusion-dependent β-thalassemia or sickle cell disease, respectively, who were followed for at least 16 months. All the participants had grade 3 or 4 adverse events. (Funded by Vertex Pharmaceuticals and CRISPR Therapeutics; CLIMB THAL-141 ClinicalTrials.gov number, NCT05356195; CLIMB SCD-151 ClinicalTrials.gov number, NCT05329649.).

Background. Studies of obinutuzumab, a type II anti-CD20 antibody, have shown efficacy in the treatment of hematologic cancers and autoimmune diseases. An evaluation of the efficacy and safety of obinutuzumab in patients with primary membranous nephropathy is needed.

Methods. In a phase 3 trial, we randomly assigned adults with primary membranous nephropathy in a 1:1 ratio to receive intravenous obinutuzumab or oral tacrolimus. The primary end point was complete remission (defined as a urinary protein-to-creatinine ratio of 0.3 or lower and a stable estimated glomerular filtration rate [eGFR]) at week 104. Key secondary end points were complete or partial remission at week 104, complete remission at week 76, a sustained reduction in the eGFR of at least 30%, duration of complete remission, and change in the Patient-Reported Outcomes Measurement Information System Fatigue T score from baseline to week 104. Fixed-sequence hierarchical testing was performed. Safety was assessed.

Results. A total of 142 patients underwent randomization. At week 104, complete remission was observed in 26 of 71 patients in the obinutuzumab group and in 4 of 70 patients in the tacrolimus group (37% vs. 6% with multiple imputation for missing data; adjusted difference, 31 percentage points; 95% CI, 18 to 44; P<0.001). The analyses of complete or partial remission at week 104 and complete remission at week 76 also showed a significant treatment effect. The analysis of a sustained eGFR reduction did not show a significant treatment effect; thus, subsequent end points in the hierarchy were not formally tested for significance. Adverse events of grade 3 or higher were reported in 16 patients (22%) in the obinutuzumab group and in 13 patients (19%) in the tacrolimus group; serious adverse events occurred in 12 (17%) and 10 (14%), respectively. There were 61 and 57 infections per 100 patient-years in the obinutuzumab and tacrolimus groups, respectively; 3 and 4 serious infections per 100 patient-years; and 11 and 14 serious adverse events per 100 patient-years. Adverse drug reactions with obinutuzumab included infusion-related reactions, respiratory tract infections, and neutropenia. One patient in each group died during escape therapy.

Conclusions. Obinutuzumab was superior to tacrolimus in inducing complete remission in patients with primary membranous nephropathy. (Funded by F. Hoffmann-La Roche; MAJESTY ClinicalTrials.gov number, NCT04629248.).

Background. Complete coronary-artery revascularization is recommended in patients with ST-segment elevation myocardial infarction (STEMI) and multivessel disease, but the preferred strategy for identifying nonculprit lesions that warrant treatment remains uncertain.

Methods. In this international, randomized trial, we assigned patients with STEMI and multivessel disease in whom the culprit lesion had been successfully treated to undergo complete coronary-artery revascularization guided by functional coronary angiography (physiology-guided group) or by conventional angiography (angiography-guided group). The primary outcome was a composite of death from any cause, myocardial infarction, cerebrovascular accident (stroke or transient ischemic attack), or ischemia-driven revascularization, assessed in a time-to-event analysis. The primary safety outcome was a composite of contrast-associated acute kidney injury or major bleeding.

Results. A total of 1823 patients underwent randomization; 913 were assigned to the physiology-guided group and 910 assigned to the angiography-guided group. The median age of the patients was 66 years (interquartile range, 58 to 76), and 24% were women. At a median follow-up of 17.9 months, a primary-outcome event had occurred in 81 patients (8.9%) in the physiology-guided group and in 125 patients (13.7%) in the angiography-guided group (hazard ratio, 0.62; 95% confidence interval [CI], 0.47 to 0.83; P<0.001). A primary-safety-outcome event occurred in 42 patients (4.6%) in the physiology-guided group and in 65 patients (7.1%) in the angiography-guided group (hazard ratio, 0.63; 95% CI, 0.43 to 0.93; P = 0.02).

Conclusions. In patients with STEMI and multivessel coronary artery disease, a strategy of complete coronary-artery revascularization guided by functional coronary angiography resulted in a lower risk of a primary-outcome event (death, myocardial infarction, cerebrovascular accident, or ischemia-driven revascularization) than a strategy guided by conventional angiography. (Funded by the Italian Health Ministry and others; AIR-STEMI ClinicalTrials.gov number, NCT05818475.).

Background. Migrants crossing the Central Mediterranean sea route travel in overcrowded vessels, where fuel may leak and contaminate seawater accumulating on the vessel floor, resulting in prolonged dermal exposure and fuel-related skin injuries. Since March 2024, clusters of cases of severe acquired methemoglobinemia with no apparent cause have been identified by clinicians in Lampedusa at disembarkation among migrants arriving in Italy.

Methods. We conducted a coordinated clinical and toxicologic investigation to characterize these cases and identify the underlying cause. Biologic samples were obtained from a subset of patients and analyzed for methemoglobin-inducing agents. A fuel sample from a vessel associated with one of the case clusters was also analyzed.

Results. Between March 2024 and December 2025, a total of 82 patients with severe acquired methemoglobinemia were identified, 90% of whom were male; the median age of the patients was 22.5 years (interquartile range, 19.5 to 28.0). The median methemoglobin level at presentation was 44.6% (interquartile range, 32.0 to 55.7), with 43% of the patients having a level of 50% or greater. Methylene blue therapy was used in 90% of the patients, often in repeated doses. Hemolytic anemia occurred as a delayed complication in 38 patients, frequently leading to blood transfusion. Two patients died. Toxicologic analysis identified N-methylaniline (a gasoline additive) or its metabolites in 37 of 39 tested patients (95%) and N-methylaniline at a concentration of 1.1% in the fuel sample from the vessel.

Conclusions. This investigation identified dermal absorption of the gasoline additive N-methylaniline from fuel-contaminated seawater as the likely cause of recurrent, life-threatening methemoglobinemia associated with maritime migration. These findings underscore the importance of methylene blue availability and frontline diagnostic capacity in settings where similar exposure conditions may occur.