Prophylactic Immunoglobulin, Vaccinations May Reduce Infections in Hematologic Malignancies

Certain approaches for preventing infection may be effective in patients with hematological malignancies, say findings from a new study published in Blood Advances.

The systematic review and meta-analysis of published data on 3 approaches to preventing acquired hypogammaglobulinemia in patients with chronic lymphocytic leukemia (CLL), non-Hodgkin lymphoma (NHL), and multiple myeloma found that prophylactic immunoglobin (Ig) and vaccinations may lower the risk of clinically documented infections in these patients. The third approach investigated was antibiotic use.

“Strategies to reduce infection are important for quality of life and mortality and are rated highly by patient and public involvement groups and in research prioritization exercises,” explained the researchers. “There is a need to understand how to prevent infections given increasing concerns about emerging antimicrobial resistance and pandemics. Interventions commonly used to prevent infections include prophylactic immunoglobulin, antibiotics, and vaccinations, but the relative effects of these approaches is unclear and assessment is difficult, given considerable variation in clinical practice.”

The researchers noted that their findings should be taken with caution, as there were low amounts of patients and a high risk of bias (RoB) across the 21 completed studies and 1 ongoing randomized controlled trial included in their analysis. All trials included in the analysis assessed the effectiveness of prophylactic immunoglobulin, vaccinations, or antibiotics.

Notably, none of the 3 approaches was found to reduce mortality.

There were 8 studies on prophylactic immunoglobulin (n = 370 patients), 7 of which were published before 2000. Five studies reported on clinically documented infections (CDIs), which showed a 28% reduced risk (risk ratio [RR], 0.72; 95% CI, 0.54-0.96) associated with the approach. The trials were moderately heterogenous. Data from 2 trials (n = 99 patients) showed that prophylactic immunoglobulin reduced the risk of at least 3 infections by 58% (RR, 0.42; 95% CI, 0.21-0.84). However, the approach significantly increased the risk of adverse events (AEs) (RR, 2.23; 95% CI ,1.67-2.99) based on data from 3 trials (n = 205 patients). AEs included fever, chills, headache, and hypotension.

The researchers noted low confidence in these findings due to the RoB assessments and the limited number of patients included in the trials, which they say were not powered to determine differences in outcomes.

They found that vaccinations, which included varicella zoster virus vaccines and flu vaccines, also lowered the risk of CDIs, with a reduced risk of 63% (RR, 0.37; 95% CI, 0.30-0.45) based on data from 6 studies (n = 3565 patients). Since the systematic review, the researchers identified 5 new trials, which similarly showed that the vaccines did not reduce mortality but significantly lowered the risk of infections.

Based on data from 5 trials (n =1567 patients), the researchers found no significant reduction in CDIs associated with antibiotics in patients who had at least 1 CDI (RR, 0.93; 95% CI, 0.79-1.08). None of these studies included patients with CLL or NHL. Similarly, data from 4 trials (n = 599 patients) showed no significant difference in infections among patients who had at least 1 serious infection (RR, 0.84; 95% CI, 0.34-2.09). The researchers noted there was statistical evidence of moderate heterogeneity.

The group also found that the approach, which included treatment with clarithromycin and bortezomib, significantly increased the risk of AEs (RR, 1.75; 95% CI, 1.01-3.03) based on data from 4 trials (n =398 patients), which has statistical evidence of moderate heterogeneity.

Reference

Chai KL, Wong JWK, Weinkove R, et al. Interventions to reduce infections in patients with hematological malignancies: a systematic review and meta-analysis. Blood Adv. Published online July 26, 2022. doi:10.1182/bloodadvances.2022008073