Comparative efficacy and safety of Pneumocystis jirovecii pneumonia prophylaxis regimens for people living with HIV: a systematic review and network meta-analysis of randomized controlled trials.

BACKGROUND: Pneumocystis jirovecii pneumonia (PCP) is a common opportunistic infection among people living with HIV (PWH), particularly among new and untreated cases. Several regimens are available for the prophylaxis of PCP, including trimethoprim-sulfamethoxazole (TMP-SMX), dapsone-based regimens (DBRs), aerosolized pentamidine (AP), and atovaquone. OBJECTIVES: To compare the efficacy and safety of PCP prophylaxis regimens in PWH by network meta-analysis. METHODS: DATA SOURCES: Embase, MEDLINE, and CENTRAL from inception to June 21, 2023. STUDY ELIGIBILITY CRITERIA: Comparative randomized controlled trials (RCTs). PARTICIPANTS: PWH. INTERVENTIONS: Regimens for PCP prophylaxis either compared head-to-head or versus no treatment/placebo. ASSESSMENT OF RISK OF BIAS: Cochrane risk-of-bias tool for RCTs 2. METHODS OF DATA SYNTHESIS: Title or abstract and full-text screening and data extraction were performed in duplicate by two independent reviewers. Data on PCP incidence, all-cause mortality, and discontinuation due to toxicity were pooled and ranked by network meta-analysis. Subgroup analyses of primary versus secondary prophylaxis, by year, and by dosage were performed. RESULTS: A total of 26 RCTs, comprising 55 treatment arms involving 7516 PWH were included. For the prevention of PCP, TMP-SMX was ranked the most favourable agent and was superior to DBRs (risk ratio [RR] = 0.54; 95% CI, 0.36-0.83) and AP (RR = 0.53; 95% CI, 0.36-0.77). TMP-SMX was also the only agent with a mortality benefit compared with no treatment/placebo (RR = 0.79; 95% CI, 0.64-0.98). However, TMP-SMX was also ranked as the most toxic agent with a greater risk of discontinuation than DBRs (RR = 1.25; 95% CI, 1.01-1.54) and AP (7.20; 95% CI, 5.37-9.66). No significant differences in PCP prevention or mortality were detected among the other regimens. The findings remained consistent within subgroups. CONCLUSIONS: TMP-SMX is the most effective agent for PCP prophylaxis in PWH and the only agent to confer a mortality benefit; consequently, it should continue to be recommended as the first-line agent. Further studies are necessary to determine the optimal dosing of TMP-SMX to maximize efficacy and minimize toxicity.

A retrospective study of intravenous pentamidine for Pneumocystis jirovecii pneumonia prophylaxis in adult patients with hematologic malignancies-its utility during respiratory virus pandemics.

OBJECTIVES: In hematology, prophylaxis for Pneumocystis jirovecii pneumonia (PCP) is recommended for patients undergoing hematopoietic stem cell transplantation and in selected categories of intensive chemotherapy for hematologic malignancies. Trimethoprim-sulfamethoxazole (TMP-SMX) is the recommended first-line agent; however, its use is not straightforward. Inhaled pentamidine is the recommended second-line agent; however, aerosolized medications were discouraged during respiratory virus outbreaks, especially during the COVID-19 pandemic, in view of potential contamination risks. Intravenous (IV) pentamidine is a potential alternative agent. We evaluated the effectiveness and tolerability of IV pentamidine use for PCP prophylaxis in adult allogeneic hematopoietic stem cell transplantation recipients and patients with hematologic malignancies during COVID-19. RESULTS: A total of 202 unique patients who received 239 courses of IV pentamidine, with a median of three doses received (1-29). The largest group of the patients (49.5%) who received IV pentamidine were undergoing or had received a hematopoietic stem cell transplant. The most common reason for not using TMP-SMX prophylaxis was cytopenia (34.7%). We have no patients who had breakthrough PCP infection while on IV pentamidine. None of the patients developed an infusion reaction or experienced adverse effects from IV pentamidine. CONCLUSIONS: Pentamidine administered IV monthly is safe and effective.

Acanthamoeba keratitis - A review.

This is a comprehensive review after a thorough literature search in PubMed-indexed journals, incorporating current information on the pathophysiology, clinical features, diagnosis, medical and surgical therapy, as well as outcomes of Acanthamoeba keratitis (AK). AK is a significant cause of ocular morbidity, and early diagnosis with timely institution of appropriate therapy is the key to obtaining good outcomes. The varied presentations result in frequent misdiagnosis, and co-infections can increase the morbidity of the disease. The first line of therapy continues to be biguanides and diamidines, with surgery as a last resort.

Effect of Pneumocystis jirovecii pneumonia prophylaxis on hematologic toxicity in patients receiving chemoradiation for primary brain tumors.

PURPOSE: Diffuse gliomas are managed with radiation and temozolomide; however, this therapy often results in hematologic toxicities. Patients undergoing chemoradiation also risk contracting Pneumocystis jirovecii pneumonia (PJP), and frequently receive prophylaxis against PJP during treatment. Independent of chemoradiation, some PJP prophylaxis drugs have the potential to cause myelosuppression, which could require cessation of chemotherapy. Here, we evaluate differences in the frequency of hematologic toxicities during chemoradiation when patients receive PJP prophylaxis. METHODS: This retrospective chart review evaluated patients with primary brain tumors treated with radiation and concurrent temozolomide. Analyses were performed to assess the effect of the type of PJP prophylaxis on risk for neutropenia, lymphopenia, or thrombocytopenia and the severity of these adverse effects as defined using the Common Terminology Criteria for Adverse Events. RESULTS: Of the 217 patients included in this analysis, 144 received trimethoprim-sulfamethoxazole (TMP/SMX) and 69 received pentamidine. Of the patients who received TMP/SMX, 15.3% developed an absolute neutrophil count < 1500 cells/µL compared with 7.2% of patients receiving pentamidine (p = 0.10). Platelet count < 100,000/µL occurred in 18.1% of patients who received TMP/SMX and 20.3% of patients who received pentamidine (p = 0.70). No significant differences in lymphocyte counts between therapies were seen. Severity of hematologic toxicities were similar between PJP prophylaxis groups. CONCLUSION: These findings suggest that the type of PJP prophylaxis does not significantly affect the risk for hematologic toxicity in brain tumor patients receiving radiation and temozolomide. Additional studies are merited to evaluate the higher rate of neutropenia in patients on TMP/SMX observed in this study.

Treatment of cutaneous leishmaniasis with a sequential scheme of pentamidine and tamoxifen in an area with a predominance of Leishmania (Viannia) guyanensis: A randomised, non-inferiority clinical trial.

OBJECTIVE: To determine whether a combination of a single intramuscular (IM) dose of pentamidine (7 mg/kg) followed by oral tamoxifen 40 mg/day for 20 days is non-inferior to three IM doses of pentamidine 7 mg/kg in the treatment of cutaneous leishmaniasis with a margin of 15%. METHODS: Phase II, randomised, controlled, open-label, non-inferiority clinical trial. Primary outcome was the complete healing of the lesions 6 months after starting treatment. Secondary outcomes were healing 3 months after starting treatment and determining the presence and severity of adverse effects (AE). RESULTS: The research was concluded with 49 patients; Leishmania (Viannia) guyanensis was the most frequent species isolated. In the primary outcome, 18 (72%) (95% CI: 52.4%-85.7%) of the 25 patients allocated to the intervention group and 24 (100%) (95% CI: 86.2%-100%) of the control group (p = 0.015) met the established criteria of cure. There was no AE with tamoxifen. CONCLUSION: Although a 72% cure rate presented by the combination of tamoxifen and pentamidine was lower than in the control group that achieved a 100% cure, it is still a safe and is a clinically relevant result. It indicates that the therapeutic scheme evaluated may be a promising option for populations in remote areas, however it should be further studied, in order to include a larger number of patients.

Therapeutic potential of pentamidine for glioma-initiating cells and glioma cells through multimodal antitumor effects.

Glioma-initiating cells, which comprise a heterogeneous population of glioblastomas, contribute to resistance against aggressive chemoradiotherapy. Using drug reposition, we investigated a therapeutic drug for glioma-initiating cells. Drug screening was undertaken to select candidate agents that inhibit proliferation of two different glioma-initiating cells lines. The alteration of proliferation and stemness of the two glioma-initiating cell lines, and proliferation, migration, cell cycle, and survival of these two differentiated glioma-initiating cell lines and three different glioblastoma cell lines treated with the candidate agent were evaluated. We also used a xenograft glioma mouse model to evaluate anticancer effects of treated glioma cell lines. Among the 1301 agents, pentamidine-an antibiotic for Pneumocystis jirovecii-emerged as a successful antiglioma agent. Pentamidine treatment suppressed proliferation and stemness in glioma-initiating cell lines. Proliferation and migration were inhibited in all differentiated glioma-initiating cells and glioblastoma cell lines, with cell cycle arrest and caspase-dependent apoptosis induction. The in vivo study reproduced the same findings as the in vitro studies. Pentamidine showed a stronger antiproliferative effect on glioma-initiating cells than on differentiated cells. Western blot analysis revealed pentamidine inhibited phosphorylation of signal transducer and activator of transcription 3 in all cell lines, whereas Akt expression was suppressed in glioma-initiating cells but not in differentiated lines. In the present study, we identified pentamidine as a potential therapeutic drug for glioma. Pentamidine could be promising for the treatment of glioblastomas by targeting both glioma-initiating cells and differentiated cells through its multifaceted antiglioma effects.

A Systematic Review of Drug-Carrying Nanosystems Used in the Treatment of Leishmaniasis.

Leishmaniasis is an infectious disease responsible for a huge rate of morbidity and mortality in humans. Chemotherapy consists of the use of pentavalent antimonial, amphotericin B, pentamidine, miltefosine, and paromomycin. However, these drugs are associated with some drawbacks such as high toxicity, administration by parenteral route, and most seriously the resistance of some strains of the parasite to them. Several strategies have been used to increase the therapeutic index and reduce the toxic effects of these drugs. Among them, the use of nanosystems that have great potential as a site-specific drug delivery system stands out. This review aims to compile results from studies that were carried out using first- and second-line antileishmanial drug-carrying nanosystems. The articles referred to here were published between 2011 and 2021. This study shows the promise of effective applicability of drug-carrying nanosystems in the field of antileishmanial therapeutics, with the perspective of providing better patient adherence to treatment, increased therapeutic efficacy, reduced toxicity of conventional drugs, as well as the potential to efficiently improve the treatment of leishmaniasis.

Bioanalytical methods for pharmacokinetic studies of antileishmanial drugs.

Bioanalytical method development and validation for the quantification of antileishmanial drugs are pivotal to support clinical trials and provide the data necessary to conduct pharmacokinetic (PK) analysis. This review provides a comprehensive overview of published validated bioanalytical assays for the quantification of antileishmanial drugs amphotericin B, miltefosine, paromomycin, pentamidine, and pentavalent antimonials in human matrices. The applicability of the assays for leishmaniasis clinical trials as well as their relevance to PK studies with emphasis on the choice of matrix, calibration range, sample volume, sample preparation, choice of internal standards, separation, and detection was discussed for each antileishmanial drug. Given that no published bioanalytical methods included multiple antileishmanial drugs in a single assay although antileishmanial shortened combination regimens currently were under investigation, it was recommended to combine various drugs in a single bioanalytical method. Furthermore, bioanalytical method development regarding target site matrix as well as applying microsampling strategies was recommended to optimize future clinical PK studies in leishmaniasis.

Pentamidine inhibits proliferation, migration and invasion in endometrial cancer via the PI3K/AKT signaling pathway.

BACKGROUND: Pentamidine has been reported to have many pharmacological effects including anti- protozoal, anti-inflammatory, and anti-tumor activities. The aim of this study is to investigate the potential therapeutic role of Pentamidine and molecular mechanisms of Pentamidine on PI3K/AKT signaling pathway underlying the anti-tumor properties in endometrial cancer. METHODS: Our study was carried out in the central laboratory of Harbin Medical University from 2019 to 2021. Human endometrial cancer cell lines Ishikawa and HEC-1A were treated with Pentamidine. The proliferation ability of cells was investigated by MTS and colony formation assays. The cell cycle distribution was detected by flow cytometry. Cell migration and invasion were analyzed by using the wound healing assay and Transwell assay. Western blotting was performed to measure the levels of AKT, p-AKT, MMP-2, and MMP-9. RESULTS: Our results revealed that treatment of Pentamidine inhibited proliferation, migration and invasion of Ishikawa and HEC-1A endometrial cancer cells. Mechanistic investigation showed that Pentamidine inhibited PI3K/AKT signaling pathway and also reduced the expression of MMP-2 and MMP-9. In addition, co-treatment with PI3K kinase inhibitor LY294002 and Pentamidine leaded to increased repression of cell viability and the protein expression of p-AKT in Ishikawa cells. CONCLUSIONS: Pentamidine suppresses PI3K/AKT signaling pathway, and inhibits proliferation, migration and invasion of EC cells. These findings suggested that Pentamidine might be a potential candidate for treating EC through PI3K/AKT pathway.

Pneumocystis jirovecii Pneumonia Prophylaxis with Intravenous Pentamidine in Adult Allogeneic Hematopoietic Stem Cell Transplant Patients.

The purpose of this single-center retrospective case series was to evaluate the efficacy and safety of 300-mg once-monthly intravenous (IV) pentamidine prophylaxis in 702 adult allogeneic hematopoietic stem cell transplant (HSCT) patients. We observed no cases of Pneumocystis jirovecii pneumonia (PJP) following IV pentamidine administration. Breakthrough Nocardia and Toxoplasma infections were observed in 7 (1%) and 5 (0.7%) patients, respectively. The most commonly reported adverse event was nausea. Monthly IV pentamidine is a reasonable alternative to trimethoprim-sulfamethoxazole (TMP-SMX).

Ninety Years of Pentamidine: The Development and Applications of Pentamidine and its Analogs.

Pentamidine, an FDA-approved human drug for many protozoal infections, was initially synthesized in the late 1930s and first reported to be curative for parasitosis in the 1940s. After ninety years of sometimes quiet growth, pentamidine and its derivatives have gone far beyond antibacterial agents, including but not limited to the ligands of DNA minor groove, modulators of PPIs (protein-protein interactions) of the transmembrane domain 5 of lateral membrane protein 1, and the blockers of the SARS-CoV-2 3a channel. This mini-review highlights the development and applications of pentamidine and its analogs, aiming to provide insights for further developing pentamidine derivatives in the following decades.

Evaluation of in vitro activity of five antimicrobial agents on Acanthamoeba isolates and their toxicity on human corneal epithelium.

BACKGROUND: Acanthamoeba keratitis (AK) is an important cause of ocular morbidity in both contact lens wearers and non wearers. Medical management comprises prolonged empiric treatment with multiple drugs, leading to adverse effects and suboptimal cure. The present study evaluated the efficiency and safety of common antimicrobial agents used in treatment of AK. METHODS: Six Acanthamoeba isolates (four AK, two water samples) were axenized and subjected to in vitro susceptibility testing against chlorhexidine, pentamidine isethionate, polymyxin B, miltefosine, and fluconazole to check for trophocidal and cysticidal activity. The safety profile was analysed by observing the cytotoxicity of the highest cidal concentration toward human corneal epithelial cell (HCEC) line. RESULTS: Chlorhexidine had the lowest cidal concentration against both cysts and trophozoites (range 4.16-25 µg/ml) followed by pentamidine isethionate (range 25-166.7 µg/ml). Both agents were nontoxic to HCEC. Polymyxin B (range 25-200 µg/ml) and fluconazole (range 64-512 µg/ml) had relatively higher minimum inhibitory concentrations (MIC); fluconazole was nontoxic even at 1024 µg/ml, but cytotoxicity was observed at 400 µg/ml with polymyxin B. Miltefosine was not effective against cysts at tested concentrations. A. castellanii were more susceptible to all agents (except pentamidine isethionate) than A. lenticulata. Clinical isolates were less susceptible to polymyxin B and fluconazole than environmental isolates, reverse was true for miltefosine. CONCLUSION: Chlorhexidine and pentamidine isethionate were the most effective and safe agents against both trophozoites and cysts forms of our Acanthamoeba isolates. Fluconazole had higher MIC but was nontoxic. Polymyxin B was effective at high MIC but therapeutic dose was found toxic. Miltefosine, at tested concentrations, could not inhibit cysts of Acanthamoeba. Clinical isolates had higher MICs for polymyxin B and fluconazole.

Case Report: Intravenous Pentamidine Rescue Treatment for Active Chronic Visceral Leishmaniasis in an HIV-1 Infected Patient.

The management of visceral leishmaniasis (VL) in HIV-infected patients is complex because of high mortality rates, toxic drug-related side effects, and a high risk of treatment failure and relapse. We report a case of active chronic VL in an HIV-1-infected woman presenting multiple secondary VL episodes over 7 years leading to massive splenomegaly and blood transfusion-dependent anemia despite several treatment courses and secondary prophylaxis. The patient was finally successfully treated with rescue treatment based on intravenous pentamidine. Twenty months after discontinuation of pentamidine the patient presented complete clinical and parasitological response. In patients with active chronic VL, treatment with intravenous pentamidine can be effective and should be considered as rescue treatment.

Drug reformulation for a neglected disease. The NANOHAT project to develop a safer more effective sleeping sickness drug.

BACKGROUND: Human African trypanosomiasis (HAT or sleeping sickness) is caused by the parasite Trypanosoma brucei sspp. The disease has two stages, a haemolymphatic stage after the bite of an infected tsetse fly, followed by a central nervous system stage where the parasite penetrates the brain, causing death if untreated. Treatment is stage-specific, due to the blood-brain barrier, with less toxic drugs such as pentamidine used to treat stage 1. The objective of our research programme was to develop an intravenous formulation of pentamidine which increases CNS exposure by some 10-100 fold, leading to efficacy against a model of stage 2 HAT. This target candidate profile is in line with drugs for neglected diseases inititative recommendations. METHODOLOGY: To do this, we evaluated the physicochemical and structural characteristics of formulations of pentamidine with Pluronic micelles (triblock-copolymers of polyethylene-oxide and polypropylene oxide), selected candidates for efficacy and toxicity evaluation in vitro, quantified pentamidine CNS delivery of a sub-set of formulations in vitro and in vivo, and progressed one pentamidine-Pluronic formulation for further evaluation using an in vivo single dose brain penetration study. PRINCIPAL FINDINGS: Screening pentamidine against 40 CNS targets did not reveal any major neurotoxicity concerns, however, pentamidine had a high affinity for the imidazoline2 receptor. The reduction in insulin secretion in MIN6 ß-cells by pentamidine may be secondary to pentamidine-mediated activation of ß-cell imidazoline receptors and impairment of cell viability. Pluronic F68 (0.01%w/v)-pentamidine formulation had a similar inhibitory effect on insulin secretion as pentamidine alone and an additive trypanocidal effect in vitro. However, all Pluronics tested (P85, P105 and F68) did not significantly enhance brain exposure of pentamidine. SIGNIFICANCE: These results are relevant to further developing block-copolymers as nanocarriers, improving BBB drug penetration and understanding the side effects of pentamidine.

Treatment of tegumentary leishmaniasis in two hemodialysis patients with end-stage renal disease using two series of pentamidine.

In this study, we present two cases of cutaneous leishmaniasis in patients with end-stage renal disease, who were treated solely with intramuscular pentamidine. In such cases, treatment implies a fine line between therapeutic efficacy and toxicity. This is suggestive of a knowledge gap; however, findings indicate that this is still the fastest and safest alternative to the treatment with antimonials. Also, it can help avoid the side effects that occur upon using antimonials.

Leishmaniavirus genetic diversity is not related to leishmaniasis treatment failure.

OBJECTIVES: The outcome of American tegumentary leishmaniasis (ATL) may depend on the presence of the Leishmania RNA virus (LRV). This virus may be involved in treatment failure. We aimed to determine whether genetic clusters of LRV1 are involved in this therapeutic outcome. METHODS: The presence of LRV1 was assessed in 129 Leishmania guyanensis isolates from patients treated with pentamidine in French Guiana. Among the 115 (89%) isolates found to carry LRV1, 96 were successfully genotyped. Patient clinical data were linked to the LRV data. RESULTS: The rate of treatment failure for LRV1-positive isolates was 37% (15/41) versus 40% (2/5) among LRV1-negative isolates (p 0.88). Concerning LRV1 genotypes, two predominant LRV1 groups emerged, groups A (23% (22/96)) and B (70% (67/96)). The treatment failure rate was 37% (3/8) for group A and 45% (9/20) for group B (p 0.31). DISCUSSION: Neither the presence nor genotype of LRV1 in patients with L. guyanensis seemed to correlate with pentamidine treatment failure.

Treatment of tegumentary leishmaniasis in two hemodialysis patients with end-stage renal disease using two series of pentamidine

Abstract In this study, we present two cases of cutaneous leishmaniasis in patients with end-stage renal disease, who were treated solely with intramuscular pentamidine. In such cases, treatment implies a fine line between therapeutic efficacy and toxicity. This is suggestive of a knowledge gap; however, findings indicate that this is still the fastest and safest alternative to the treatment with antimonials. Also, it can help avoid the side effects that occur upon using antimonials.

Distribution, treatment outcome and genetic diversity of Leishmania species in military personnel from Colombia with cutaneous leishmaniasis.

BACKGROUND: Leishmaniasis is one of the most important infectious diseases affecting the Colombian National Army due to the high number of reported cases and exposure throughout military operations in endemic areas. The main aim of this study was to estimate the geographical distribution along with the genetic diversity and treatment outcome of Leishmania species in Colombian military personnel. METHODS: Skin lesion samples by smear and aspirate were collected in 136 patients having parasitological cutaneous leishmaniasis (CL) diagnosis. DNA was extracted, the nuclear marker heat shock protein 70 (HSP70) was amplified by PCR and sequenced. Leishmania species were identified by BLASTn. The geo-spatial distribution of the identified parasites was determined according to the possible site of infection. Gene tree was constructed by maximum likelihood (ML), diversity indices (π, h) were estimated and haplotype network was constructed under the Templeton-Crandall-Sing algorithm in order to determine the geographic relationships of the genetic variants of Leishmania species circulating in Colombian military population. RESULTS: The species were identified in 77.94% of the samples, with a predominance of L. braziliensis (65.09%), followed by L. panamensis (31.13%), L. naiffi by the first time reported in Colombia in two patients (1.89%) as well as L. lindenbergi in a single patient (0.945%) with possible infection in the municipality of Miraflores, Guaviare and L. infantum in a single patient (0.945%) notified with CL in the municipality of Tumaco, Nariño. The phylogenetic analysis was consistent according to bootstrap, showing four strongly differentiated clades. CONCLUSIONS: The geo-spatial distribution suggested that L. braziliensis has a greater abundance, while L. panamensis has a greater dispersion. The phylogenetic relationships of Leishmania species in Colombian military personnel was estimated with the confirmation of two new species circulating without prior report in the country and a species with no background for CL in the Colombian army. A substantial genetic diversity of Leishmania braziliensis was defined. This study contributes through the understanding of the molecular epidemiology to the CL transmission in Colombia.

Higher risk of urinary tract infections in renal transplant recipients receiving pentamidine versus trimethoprim-sulfamethoxazole (TMP-SMX) for Pneumocystis pneumonia prophylaxis.

Urinary tract infection (UTI) is one of the most common infectious complications among renal transplant patients. Trimethoprim-sulfamethoxazole (TMP-SMX) is routinely used as first-line prophylaxis against Pneumocystis pneumonia (PCP) and other opportunistic infections including UTI. Aerosolized pentamidine is an alternate agent used for PCP prophylaxis; however, it does not provide coverage against uropathogens. This is a retrospective study of 81 renal transplant recipients who received TMP-SMX or aerosolized pentamidine for PCP prophylaxis at our center over 1 year. Survival analysis demonstrated increased cumulative incidence of UTI among patients receiving pentamidine for PCP prophylaxis compared to those receiving TMP-SMX (log-rank test P < .001). Univariate and multivariate Cox proportional hazard regression model showed pentamidine prophylaxis (HR 3.740; 95% CI 1.745-8.016; P = .001) and female sex (HR 4.025; 95% CI 1.770-9.154; P = .001) to independently increase UTI risk. Age, induction agent, graft type, diabetes, and delayed graft function (DGF) were not associated with increased risk. This study concludes that the use of pentamidine for PCP prophylaxis compared to TMP-SMX is associated with increased risk of UTI. Secondary UTI prophylaxis may be considered for patients who are unable to tolerate TMP-SMX and who have other risk factors for UTI; however, the efficacy of this has not been studied.

Effectiveness and tolerability of intravenous pentamidine for Pneumocystis carinii pneumonia prophylaxis in adult hematopoietic stem cell transplant patients: a retrospective study.

BACKGROUND: Pneumocystis carinii pneumonia (PCP) prophylaxis is recommended after hematopoietic stem cell transplantation (HSCT). In patients who are unable to take first-line prophylaxis, trimethoprim/sulfamethoxazole, aerosolized pentamidine is recommended. This drug may not, however, be available at all institutions, and its administration requires special techniques. Therefore, intravenous pentamidine (IVP) has been used in adult patients as an alternative, despite limited data. We evaluated the effectiveness and tolerability of IVP for PCP prophylaxis in adult patients who had undergone HSCT. METHODS: A single-center retrospective study was conducted of adult patients who had undergone allogenic or autologous HSCT between January 2014 and September 2018 and had received at least three doses of IVP for PCP prophylaxis. The IVP dose was 4 mg/kg administered monthly. Data on PCP infection and adverse reactions were collected from both patients' electronic medical records and the pharmacy adverse drug reactions documentation system. Patients were followed from the start of IVP up to 6 months after discontinuation of therapy. A confirmed PCP infection was defined as radiographic evidence of PCP and positive staining of a respiratory specimen. Descriptive statistics were used to analyze the study outcomes. RESULTS: During the study period, 187 patients were included. The median age was 36.4 years (range, 18-64), 58% were male, and 122 (65%) had received allogeneic HSCT while the remainder autologous HSCT. The median number of IVP doses administered per patient was 5 (range, 3-29). During the study period, none of the patients had evidence of confirmed PCP infection. However; there were two cases with high clinical suspicion of PCP infection (i.e. required anti-pneumocystis therapy) and one reported case of central nervous system toxoplasmosis while receiving IVP for PCP prophylaxis. Only one case of nausea associated with IVP administration was reported. CONCLUSIONS: In a cohort of adult patients with HSCT who received IVP for PCP prophylaxis, there was no evidence of confirmed PCP infection, and the treatment appeared to be well tolerated. Prospective studies should be conducted to confirm the efficacy and tolerability of IVP.