Trimethoprim–sulfamethoxazole reduces severe infections following rituximab for vasculitis
medwireNews: A study looking at risk factors for the development of severe infections in patients with antineutrophil cytoplasm antibody-associated vasculitis (AAV) following rituximab has found that trimethoprim–sulfamethoxazole prophylaxis may be of benefit.
Prophylactic trimethoprim–sulfamethoxazole significantly reduced the risk for severe (grade ≥3) infections in rituximab-treated patients with AAV by 70%.
Conversely, older age, endobronchial involvement, the presence of chronic obstructive pulmonary disease, and the administration of alemtuzumab prior to rituximab all significantly increased the risk for severe infections, with hazard ratios (HRs) of 1.03, 2.21, 6.30, and 3.97, respectively.
Respiratory tract infections accounted for two-thirds of all infections, and a separate analysis found that significant independent risk factors were endobronchial involvement (HR=4.30), severe bronchiectasis (HR=7.48), increased neutrophil count at baseline (HR=1.19), and major relapse (HR=2.65).
“Comorbidities, either attributable to active disease or immunosuppression, remain a major issue in the management of AAV,” write Andreas Kronbichler (Addenbrooke’s Hospital, Cambridge, UK) and colleagues in the Annals of the Rheumatic Diseases, with infections being a primary cause of death.
And although rituximab has shown efficacy in inducing remission in patients with AAV, the researchers note that several observational studies have reported severe or life-threatening infectious complications following rituximab therapy.
A total of 192 patients with rituximab-treated AAV were included in the analysis and were followed up for a mean of 22.7 months after starting rituximab treatment.
Overall, 49 (25.5%) patients experienced 95 severe infections, giving an overall event rate of 26.06 per 100 person–years.
Antibiotic prophylaxis with trimethoprim–sulfamethoxazole was given to 73 (38%) of the 192 individuals, with most patients (38.4%) receiving 480 mg on alternate days. Although the therapy was stopped in five patients because of adverse events, those who tolerated trimethoprim–sulfamethoxazole prophylaxis remained on it for a mean of 14.7 months.
While the current results require confirmation, the researchers conclude that “they support [the] routine use of trimethoprim–sulfamethoxazole in rituximab-treated patients.”
By Catherine Booth
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