Network Meta-Analysis: TMP-SMX May Need Reassessment as First-Line Therapy for PCP in People With HIV

Background: Pneumocystis jirovecii pneumonia (PCP) remains a severe opportunistic infection in people living with HIV (PWH), especially those with low CD4 counts. Trimethoprim–sulfamethoxazole (TMP-SMX) is widely recommended as first-line therapy; however, its toxicity profile can limit use. Alternative regimens such as dapsone–trimethoprim, clindamycin–primaquine, atovaquone, and pentamidine have been explored, but comprehensive comparative data are scarce.

Objective: This systematic review and network meta-analysis aimed to compare the efficacy (treatment failure, mortality) and tolerability (treatment change due to toxicity) of PCP treatment regimens in PWH. The goal was to determine whether TMP-SMX maintains superiority across these outcomes or if alternative regimens offer similar efficacy with improved safety profiles.

Methods: Researchers systematically searched Embase, Medline, and CENTRAL (inception through 3 February 2024) for randomized controlled trials (RCTs) comparing at least two PCP treatment regimens in PWH. Independent reviewers screened titles/abstracts and performed full-text reviews. Data extraction included population demographics, treatment arms, outcomes (treatment failure, all-cause mortality, treatment change), and risk-of-bias assessments using the Cochrane Risk-of-Bias 2 tool. A network meta-analysis using a frequentist random-effects model was performed to integrate direct and indirect comparisons, estimating relative treatment effects (risk ratios with 95% confidence intervals) and generating rankings via the surface under the cumulative ranking curve (SUCRA).

Results: Fourteen RCTs (1983–1996) with 1,788 participants across 27 treatment arms were included. No regimen demonstrated significant superiority over TMP-SMX in direct comparisons, although TMP-SMX outperformed atovaquone and trimetrexate plus folinic acid in reducing treatment failure. In the network analysis, clindamycin–primaquine, intravenous pentamidine, and TMP-SMX all had favorable SUCRA values for preventing treatment failure. For all-cause mortality, dapsone–trimethoprim and intravenous pentamidine ranked highest, while TMP-SMX was better than atovaquone in direct comparison. Notably, for tolerability, all alternative regimens tended to be safer than TMP-SMX, which ranked worst for toxicity. Inhaled pentamidine, trimetrexate plus folinic acid, and atovaquone were the best-tolerated therapies.

Conclusions: These findings suggest that TMP-SMX, although commonly used, might not be universally superior to all other regimens when balancing efficacy and safety in PWH with PCP. When the risk of renal or hematologic complications is high, considering clindamycin–primaquine or intravenous pentamidine may provide comparable efficacy with a more favorable safety profile. Inhaled pentamidine or atovaquone may offer good tolerability but should be carefully assessed for efficacy in moderate-to-severe disease.

Implications for Practice: When managing PCP in PWH, TMP-SMX may not always be the ideal standalone first-line choice, especially in patients at high risk for renal or hematologic complications. Clindamycin–primaquine and intravenous pentamidine could represent viable alternatives for clinicians seeking to balance efficacy with improved safety. Inhaled pentamidine or atovaquone may offer strong tolerability but should be carefully evaluated for their effectiveness in moderate-to-severe disease.

Study Strengths and Limitations: Strengths include a robust search strategy, strict inclusion criteria of RCTs, and the use of a network meta-analysis to integrate direct and indirect comparisons. Limitations involve the older timeframe of the included trials (most conducted before the modern ART era) and heterogeneous definitions of treatment failure, which may limit generalizability to broader contemporary clinical settings. Women and other high-risk populations were underrepresented, presenting another limitation.

Future Research: Contemporary RCTs should address the optimal dose and duration of TMP-SMX and alternative agents, include underrepresented groups (women, older adults, patients with renal impairment), and consider modern management of HIV and critical care practices. Ongoing investigations of novel agents like rezafungin may further refine first-line PCP treatment strategies.

Reference: Hatzl S, Posch F, Scholz L, … Bassetti M, Hoenigl M, Krause R. Comparative efficacy and safety of treatment regimens for Pneumocystis jirovecii pneumonia in people living with HIV: a systematic review and network meta-analysis of randomized controlled trials. Clinical Microbiology and Infection, Published online December 26, 2024. DOI: http://doi.org/10.1016/j.cmi.2024.12.024