Immune-checkpoint-inhibitor (ICI)–associated myotoxicity involves the heart (myocarditis) and skeletal muscles (myositis), which frequently occur concurrently and are highly fatal. We report the results of a strategy that included identification of individuals with severe ICI myocarditis by also screening for and managing concomitant respiratory muscle involvement with mechanical ventilation, as well as treatment with the CTLA4 fusion protein abatacept and the JAK inhibitor ruxolitinib. Forty cases with definite ICI myocarditis were included with pathologic confirmation of concomitant myositis in the majority of patients. In the first 10 patients, using recommended guidelines, myotoxicity-related fatality occurred in 60%, consistent with historical controls. In the subsequent 30 cases, we instituted systematic screening for respiratory muscle involvement coupled with active ventilation and treatment using ruxolitinib and abatacept. The abatacept dose was adjusted using CD86 receptor occupancy on circulating monocytes. The myotoxicity-related fatality rate was 3.4% (1/30) in these 30 patients versus 60% in the first quartile (P < 0.0001). These clinical results are hypothesis-generating and need further evaluation. Significance: Early management of respiratory muscle failure using mechanical ventilation and high-dose abatacept with CD86 receptor occupancy monitoring combined with ruxolitinib may be promising to mitigate high fatality rates in severe ICI myocarditis. See related commentary by Dougan, p. 1040. This article is highlighted in the In This Issue feature, p. 1027

Background: Colistin often remains the only active agent against multidrug-resistant Gram-negative pathogens. The aim of the study was to assess efficacy of nebulized colistin for treating ventilator-associated pneumonia (VAP) caused by multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii. Methods: One hundred and sixty-five patients with VAP caused by P. aeruginosa and A. baumannii were enrolled in a prospective, observational, and comparative study. The sensitive strain group included 122 patients with VAP caused by P. aeruginosa and A. baumannii susceptible to β-lactams, aminoglycosides, or quinolones and treated with intravenous antibiotics for 14 days. The multidrug-resistant strain group included 43 patients with VAP caused by multidrug-resistant P. aeruginosa and A. baumannii and treated with nebulized colistin (5 million international units every 8 h) either in monotherapy (n=28) or combined to a 3-day intravenous aminoglycosides for 7-19 days. The primary endpoint was clinical cure rate. Aerosol was delivered using vibrating plate nebulizer. Results: After treatment, clinical cure rate was 66% in sensitive strain group and 67% in multidrug-resistant strain group (difference -1%, lower limit of 95% CI for difference -12.6%). Mortality was not different between groups (23 vs. 16%). Among 16 patients with persisting or recurrent P. aeruginosa infection, colistin minimum inhibitory concentration increased in two patients. Conclusion: Nebulization of high-dose colistin was effective to treat VAP caused by multidrug-resistant P. aeruginosa or A. baumannii. Its therapeutic effect was noninferior to intravenous β-lactams associated with aminoglycosides or quinolones for treating VAP caused by susceptible P. aeruginosa and A. baumannii.

Introduction: Systemic lupus erythematosus (SLE) is a T and B cell-dependent autoimmune disease characterized by the appearance of autoantibodies, a global regulatory T cells (Tregs) depletion and an increase in Th17 cells. Recent studies have shown the multifaceted immunomodulatory effects of vitamin D, notably the expansion of Tregs and the decrease of Th1 and Th17 cells. A significant correlation between higher disease activity and lower serum 25-hydroxyvitamin D levels [25(OH)D] was also shown. Methods: In this prospective study, we evaluated the safety and the immunological effects of vitamin D supplementation (100 000 IU of cholecalciferol per week for 4 weeks, followed by 100 000 IU of cholecalciferol per month for 6 months.) in 20 SLE patients with hypovitaminosis D. Results: Serum 25(OH)D levels dramatically increased under vitamin D supplementation from 18.7±6.7 at day 0 to 51.4±14.1 (p<0.001) at 2 months and 41.5±10.1 ng/mL (p<0.001) at 6 months. Vitamin D was well tolerated and induced a preferential increase of naïve CD4⁺ T cells, an increase of regulatory T cells and a decrease of effector Th1 and Th17 cells. Vitamin D also induced a decrease of memory B cells and anti-DNA antibodies. No modification of the prednisone dosage or initiation of new immunosuppressant agents was needed in all patients. We did not observe SLE flare during the 6 months follow-up period. Conclusions: This preliminary study suggests the beneficial role of vitamin D in SLE patients and needs to be confirmed in randomized controlled trials.

Oral antimalarial agents, most commonly hydroxychloroquine sulfate, are considered the first-line systemic treatment for cutaneous lupus erythematosus (CLE).¹ The prescribed hydroxychloroquine sulfate dosage theoretically depends on the patient's weight, with a maximal daily dose of 6.0 to 6.5 mg/kg adjusted to the ideal body weight (calculated in daily use as [body length in centimeters − 100] − 10% for men and [body length in centimeters− 100] − 15% for women).² Nonetheless, the standard daily dosage in France is frequently 2 tablets of hydroxychloroquine sulfate (ie, 400 mg/d), regardless of the patient's height and weight. The few studies that have addressed the pharmacokinetic variables underlying the management of hydroxychloroquine therapy in systemic diseases such as rheumatoid arthritis and systemic lupus erythematosus (SLE)^3-5 reveal great interindividual variability in blood hydroxychloroquine concentrations and thus raise the question of a relation between concentration and efficacy and of the utility of monitoring these concentrations. We have reported that a low blood hydroxychloroquine concentration is a marker of SLE activity and a predictor of lupus flares in patients with this disease and suggested a target blood hydroxychloroquine level of 1000 ng/mL for them.⁵

Objective: Blood concentrations of hydroxychloroquine (HCQ) vary widely among patients with systemic lupus erythematosus (SLE). A pharmacokinetic/pharmacodynamic relationship has been found in different situations, and a very low blood concentration of HCQ is a simple marker of nonadherence to treatment. Therefore, interest in blood HCQ concentration measurement has increased, but little is known about factors that influence blood HCQ concentration variability. This study was undertaken to analyze determinants of blood HCQ concentrations.Methods: We conducted a retrospective analysis of patient data, including data from the Plaquenil Lupus Systemic (PLUS) study, to determine the association of epidemiologic, clinical, and biologic factors with blood HCQ concentrations. Data for nonadherent patients (blood HCQ concentration <200 ng/ml) were excluded.Results: To examine homogeneous pharmacologic data, we restricted the analyses of the PLUS data to the 509 SLE patients receiving 400 mg/day. We found no association of ethnicity or smoking with blood HCQ concentrations and no pharmacokinetic drug–drug interaction with antacids or with inhibitors or inducers of cytochrome P450 enzymes. On multivariate analysis, high body mass index (P = 0.008), no treatment with corticosteroids (P = 0.04), increased time between the last tablet intake and measurement of blood HCQ concentrations (P = 0.017), low platelet count (P < 0.001), low neutrophil count (P < 0.001), and high estimated creatinine clearance (P < 0.001) were associated with low blood HCQ concentrations. In 22 SLE patients with chronic renal insufficiency (median serum creatinine clearance 52 ml/minute [range 23–58 ml/minute]) who received 400 mg/day HCQ, the median blood HCQ concentration was significantly higher than that in the 509 patients from the PLUS study (1,338 ng/ml [range 504–2,229 ng/ml] versus 917 ng/ml [range 208–3316 ng/ml]) (P < 0.001).Conclusion: We provide a comprehensive analysis of determinants of blood HCQ concentrations. Because this measurement is increasingly being used, these data might be useful for clinicians.