Real-world Experience of Posaconazole Therapeutic Drug Monitoring in Oncology Patients: Clinical Implications of Hypoalbuminemia as a Predictor of Subtherapeutic Posaconazole Levels.

Background: Posaconazole maintains broad antifungal activity and is employed for prevention and treatment of invasive fungal infections in oncology patients. Older formulations required therapeutic drug monitoring, and specific plasma drug levels have been recommended. This study evaluated factors associated with subtherapeutic concentrations with the newer delayed-release tablet formulation. Methods: In this retrospective, single-center cohort study at a national comprehensive cancer center, all oncology patients receiving delayed-release posaconazole at standard dosing of 300 mg orally per day from 06/2021 to 07/2023 with plasma drug concentration evaluation were identified. Demographic, clinical, and laboratory data were evaluated to identify risk factors associated with subtherapeutic drug levels at targets of ≥1.25 µg/mL and ≥1.8 µg/mL. Results: Of 110 patients identified, 98 met criteria for inclusion in the study. The median time from initiation of posaconazole to drug level assessment was 13 days, and the median concentration was 1.29 µg/mL. Of the 22 patients receiving posaconazole for prophylaxis, 5 (22.7%) failed to achieve concentrations ≥0.7 µg/mL, and of 76 patients receiving posaconazole for treatment, 38 (50%) failed to achieve concentrations of ≥1.25 µg/mL. In multivariable analysis, albumin of ≤3 g/dL and ideal body weight ≥60 kg were found to be associated with subtherapeutic levels. For a higher target of ≥1.8 µg/mL, only albumin ≤3 g/dL was associated with subtherapeutic levels for the variables evaluated. Conclusions: A higher initial dosing strategy and therapeutic drug monitoring for oncology patients with albumin ≤3 g/dL receiving posaconazole, particularly for the treatment of invasive fungal infection, could be considered.

Real-World Use of Isavuconazole as Primary Therapy for Invasive Fungal Infections in High-Risk Patients with Hematologic Malignancy or Stem Cell Transplant.

(1) Introduction: Invasive fungal infections (IFIs) are a major cause of morbidity and mortality among immunocompromised patients with hematologic malignancies (HM) and stem cell transplants (SCT). Isavuconazole was approved by FDA as a primary therapy for Invasive Aspergillosis (IA) and Mucormycosis. The aim of this study is to look at the real-world use of Isavuconazole in patients with HM and evaluate their clinical outcomes and safety. (2) Methods: We conducted a retrospective study of HM patients at MD Anderson Cancer Center who had definite, probable or possible mold infections between 1 April 2016 and 31 January 2020 and were treated with Isavuconazole for a period of at least 7 days. Clinical and radiological findings were assessed at baseline and at 6 and 12 weeks of follow up. (3) Results: We included 200 HM patients with IFIs that were classified as definite (11), probable (63) and possible (126). Aspergillus spp was the most commonly isolated pathogen. The majority of patients (59%) received prophylaxis with anti-mold therapy and Isavuconazole was used as a primary therapy in 43% of patients, and as salvage therapy in 58%. The switch to Isavuconazole was driven by the failure of the primary therapy in 66% of the cases and by adverse effects in 29%. Isavuconazole was used as monotherapy in 30% of the cases and in combination in 70%. Adverse events possibly related to Isavuconazole were reported in eight patients (4%) leading to drug discontinuation. Moreover, a favorable response with Isavuconazole was observed in 40% at 6 weeks and in 60% at 12 weeks. There was no significant difference between isavuconazole monotherapy and combination therapy (p = 0.16 at 6 weeks and p = 0.06 at 12 weeks). Finally, there was no significant difference in outcome when Isavuconazole was used after failure of other anti-mold prophylaxis or treatment versus when used de novo as an anti-mold therapy (p = 0.68 at 6 weeks and p = 0.25 at 12 weeks). (4) Conclusions: Whether used as first-line therapy or after the failure of other azole and non-azole prophylaxis or therapies, isavuconazole seems to have a promising clinical response and a good safety profile as an antifungal therapy in high-risk cancer patients with hematologic malignancies. Moreover, combination therapy did not improve the outcome compared to Isavuconazole therapy.

Extensively Drug-Resistant Myroides odoratus in Critically Ill Patients: A Case Series and Literature Review.

The bacterial genus Myroides, like other members of the Flavobacteriaceae family, consists of aerobic, non-motile, Gram-negative bacilli. Myroides spp. is considered predominantly opportunistic pathogens as, historically, most documented infections have been in immunocompromised individuals. Along with advancements in molecular assay testing, there are growing reports of clinically relevant Myroides spp. infections in immunocompetent individuals. These organisms display broad antimicrobial resistance, and while research into their mechanisms of resistance is progressing, genetic testing has revealed metallo-ß-lactamases present in their genome. The sporadic identification of Myroides spp. and ongoing clarification of resistance patterns make empiric treatment difficult. This report documents two cases of extensively drug-resistant Myroides odoratus isolated from critically ill but otherwise immunocompetent patients followed by a review of available literature on Myroides spp. antibiotic sensitivities. Our findings indicate that minocycline and moxifloxacin have the highest documented in vitro activity against Myroides spp.

Impact of Infections in Patients Receiving Pembrolizumab-Based Therapies for Non-Small Cell Lung Cancer.

Background: Immune checkpoint inhibitor (ICI) therapy has significantly improved outcomes across a range of malignancies. While infections are a well-known contributor to morbidity and mortality amongst patients receiving systemic chemotherapy regimens, little is known about the impact of infections on patients receiving ICI therapy. This study aims to assess incidence, risk factors, and outcomes in patients who develop infections while on pembrolizumab-based therapies for non-small cell lung cancer (NSCLC). Methods: Patients receiving pembrolizumab for stage III/IV NSCLC from 1/1/2017-8/1/2021 across seven hospitals were identified. Incidence and type of infection were characterized. Covariates including baseline demographics, treatment information, treatment toxicities, and immunosuppressive use were collected and compared between infected and non-infected patients. Outcomes included the rate of infections, all-cause hospital admissions, median number of treatment cycles, overall survival (OS), and progression free survival (PFS). Univariable and multivariable analysis with reported odds ratio (OR) and 95% confidence intervals (CI) were utilized to evaluate infection risks. OS and PFS were analyzed by Kaplan−Meier analysis and tested by log-rank test. p-value < 0.05 was considered statistically significant. Results: There were 243 NSCLC patients that met the inclusion criteria. Of these, 111 (45.7%) had one documented infection, and 36 (14.8%) had two or more. Compared to non-infected patients, infected patients had significantly more all-cause Emergency Department (ED) [37 (33.3%) vs. 26 (19.7%), p = 0.016], hospital [87 (78.4%) vs. 53 (40.1%), p < 0.001], and ICU visits [26 (23.4%) vs. 5 (3.8%), p < 0.001], and had poorer median OS (11.53 [95% CI 6.4−16.7] vs. 21.03 [95% CI: 14.7−24.2] months, p = 0.033). On multivariable analysis, anti-infective therapy (OR 3.32, [95% CI: 1.26−8.76], p = 0.015) and ECOG of >1 (OR 5.79, [95% CI 1.72−19.47], p = 0.005) at ICI initiation conferred an increased risk for infections. At last evaluation, 74 (66.7%) infected and 70 (53.0%) non-infected patients died (p = 0.041). Conclusion: Infections occurred in nearly half of patients receiving pembrolizumab-based therapies for NSCLC. Infected patients had frequent hospitalizations, treatment delays, and poorer survival. ECOG status and anti-infective use at ICI initiation conferred a higher infection risk. Infection prevention and control strategies are needed to ameliorate the risk for infections in patients receiving ICIs.

Skin and Soft Tissue Infections in Non-Human Immunodeficiency Virus Immunocompromised Hosts.

Skin and soft tissue infections among the non-human immunodeficiency virus infected immunosuppressed population are a serious and growing concern. Many pathogens can cause cutaneous infections in these patients owing to the highly varied and profound immune deficits. Although patients can be infected by typical organisms, the diversity and antimicrobial-resistant nature of the organisms causing these infections result in significant morbidity and mortality. The diagnostic approach to these infections in immunocompromised hosts can differ dramatically depending on the potential causative organisms. An understanding of new immunosuppressive treatments and evolving antimicrobial resistance patterns are required to optimally manage these difficult cases.

Successful Outcomes of Severe COVID-19 in Patient with Chronic Lymphocytic Leukemia: Diagnostic Challenges in Immunocompromised Hosts.

The emergence and spread of 2019 novel coronavirus have led to an unprecedented public health crisis around the globe, threatening the lives of millions of people. We report a severe case of COVID-19 in a patient with chronic lymphocytic leukemia and describe primarily the clinical presentation and the challenges encountered in the COVID-19 diagnosis, treatment, and specimens sampling pitfalls. This case highlights the importance of a comprehensive diagnostic approach of pneumonia in immunocompromised hosts, including timely and safe bronchoscopy, because of the broad differential diagnosis, more challenging with the current outbreak of COVID-19.