Fungal pneumonia in patients with hematologic malignancies: current approach and management

Fungal-associated pneumonia in patients with hematological malignancies

PURPOSE

Patients with hematologic malignancies (HM) are at high risk of invasive lung fungal infections (ILFI). To describe the main characteristics, treatment, and outcomes for five years in adult patients with HM and fungal pneumonia.

METHODS

We conducted a retrospective study at Instituto Nacional de Cancerología (INCan), a referral tertiary care oncology hospital with 135 beds in Mexico City, Mexico. We included all cases of fungal pneumonia in patients with HM from January 1, 2017, to December 31, 2022. Cases were classified as proven, probable, and possible according to EORTC/MSG criteria 2021.

RESULTS

Two hundred ten patients were included; the mean age was 40 years. The most frequent HM was acute lymphoblastic leukemia (n=74) and acute myeloid leukemia (n=68). One hundred forty patients (66.7%) had severe neutropenia for a median of 16 days. All patients had a CT thorax scan; in 132 (62.9%), multiple nodules were documented. Serum galactomannan (GM) was positive in 21/192 (10.9%) and bronchoalveolar lavage in 9/36 (25%). Fifty-three patients (25.2%) died in the first month. In the multivariate analysis for mortality in the first 30 days, hypoalbuminemia, shock, possible ILFI, and inappropriate antifungal treatment were statistically associated.

CONCLUSIONS

In high-risk HM patients, CT thorax scan and GM help diagnose ILFI. An appropriate antifungal improves mortality.

Utility of Bronchoalveolar Lavage for the Diagnosis and Management of COVID-19 in Patients With Cancer

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction (PCR) on nasopharyngeal swab (NPS), remains the most reliable and practical test to diagnose coronavirus disease 2019 (COVID-19). Current literature is sparse regarding the rates of discordance between NPS and bronchoalveolar lavage (BAL) in patients with cancer.

METHODS

We conducted a retrospective cohort study of adult patients with cancer who had BAL samples tested for SARS-CoV-2 at a comprehensive cancer center. Patients without NPS PCR for SARS-CoV-2 before BAL were excluded.

RESULTS

In a cohort of 345 patients, 12% and 17% tested positive for SARS-CoV-2 on NPS and BAL, respectively. There was a 6.3% NPS-/BAL+ discordance rate and a 9.5% NPS+/BAL- discordance rate. Patients with lymphoma (adjusted odds ratio [aOR] = 4.06; P = .007) and Hispanic patients (aOR = 3.76; P = .009) were more likely to have NPS-/BAL+ discordance on multivariate analysis. Among patients with NPS- /BAL- for SARS-CoV-2, an alternate infectious (23%) and a noninfectious etiology (16%) were identified in BAL.

CONCLUSIONS

Our discordance rates between NPS and BAL were sufficient to recommend BAL in certain patients with cancer with a high clinical suspicion of COVID-19. BAL has value in identifying alternative etiologies of illness in patients with suspected or confirmed COVID-19.

Treatment of infections in cancer patients: an update from the neutropenia, infection and myelosuppression study group of the Multinational Association for Supportive Care in Cancer (MASCC)

INTRODUCTION

Patients with hematological and advanced solid malignancies have acquired immune dysfunction, often exacerbated by treatment, posing a significant risk for the development of infections. This review evaluates the utility of current clinical and treatment guidelines, in the setting of management of infections in cancer patients.

AREAS COVERED

These include causes of infection in cancer patients, management of patients with high-risk and low-risk febrile neutropenia, management of low-risk patients in an outpatient setting, the role of granulocyte colony-stimulating factor (G-CSF) in the prevention and treatment of neutropenia-related infections, management of lung infections in various clinical settings, and emerging challenges surrounding the risk of infection in cancer patients treated with novel treatments. The literature search was performed by accessing PubMed and other databases, focusing on published clinical trials of relevant anti-cancer agents and diseases, primarily covering the recent past, but also including several key studies published during the last decade and, somewhat earlier in a few cases.

EXPERT REVIEW

Notwithstanding the promise of gene therapy/gene editing in hematological malignancies and some types of solid cancers, innovations introduced in clinical practice include more discerning clinical management such as the generalized use of biosimilar formulations of G-CSF and the implementation of novel, innovative immunotherapies.

Murine Models of Hematopoietic Cell Transplantation to Investigate Fungal Infections

Animal models are fundamental to unravel the complex nature of fungal infections in the host context. Here, a versatile murine model of hematopoietic cell transplantation (HCT) is described. This model can be used to investigate the establishment and progression of fungal infections after HCT and to elucidate how different transplant variables affect the recovery of host immunity.

Isavuconazole as Primary Antifungal Prophylaxis in Patients With Acute Myeloid Leukemia or Myelodysplastic Syndrome: An Open-label, Prospective, Phase 2 Study

BACKGROUND

Mold-active primary antifungal prophylaxis (PAP) is routinely recommended in neutropenic patients with newly diagnosed acute myeloid leukemia (AML) or high-risk myelodysplastic syndrome (MDS) undergoing remission-induction chemotherapy (RIC). Isavuconazole (ISAV) is an extended spectrum mold-active triazole and has superior tolerability and fewer significant drug-drug interactions compared with other triazoles.

METHODS

In our investigator-initiated, phase 2 trial, treatment-naive adult patients with AML or MDS starting RIC received ISAV per the dosing recommendations in the US label until neutrophil recovery (absolute neutrophil count [ANC] ≥ 0.5 × 109/L) and attainment of complete remission, occurrence of invasive fungal infection (IFI), or for a maximum of 12 weeks. The primary endpoint was the incidence of proven/probable IFI during ISAV PAP and up to 30 days after the last dose.

RESULTS

Sixty-five of 75 enrolled patients received ISAV PAP (median age, 67 years, median ANC at enrollment, 0.72 × 109/L). Thirty-two patients (49%) received oral targeted leukemia treatments (venetoclax, FTL3 inhibitors). Including the 30-day follow-up period, probable/proven and possible IFIs were encountered in 4 (6%) and 8 patients (12%), respectively. ISAV trough serum concentrations were consistently > 1 µg/mL, showed low intraindividual variation, and were not significantly influenced by chemotherapy regimen. Tolerability of ISAV was excellent, with only 3 cases (5%) of mild to moderate elevations of liver function tests and no QTc prolongations.

CONCLUSIONS

ISAV is a safe and effective alternative for PAP in patients with newly diagnosed AML/MDS undergoing RIC in the era of recently approved or emerging small-molecule antileukemia therapies.

CLINICAL TRIALS REGISTRATION

NCT03019939.

Respiratory Infections

Pneumonia is defined as the presence of a new pulmonary infiltrate on radiologic imaging in the patient with appropriate clinical symptoms such as fever, cough, production of purulent sputum, shortness of breath and/or hypoxia, in the absence of pulmonary edema [1, 2].

Candida and invasive mould diseases in non-neutropenic critically ill patients and patients with haematological cancer

Critically ill patients and patients with haematological cancer are HIV-negative populations at high risk of invasive fungal infections. In intensive-care units, candidaemia and intra-abdominal candidiasis predominate, but aspergillosis has emerged as a lethal, under-recognised cause of pneumonia. In patients with haematological malignancies or who have undergone stem-cell transplantations, pulmonary disease due to aspergillus and other mould diseases predominate. In this Series paper, we provide an update on risk assessment, new diagnostic strategies, and therapeutic approaches. New concepts have emerged for use of risk prediction rules and an evidence base now exists for inclusion of biomarkers (eg, galactomannan, 1,3-β-D-glucan, and PCR assays for Aspergillus spp) into early diagnostic and therapeutic strategies. Imaging techniques remain helpful for early diagnosis of pulmonary mould diseases, with PET techniques offering potential improvements in diagnostic specificity and evaluation of clinical response. Echinocandins and triazoles have been validated extensively for prophylaxis, empirical therapy, and targeted therapy, but an increase in intrinsically resistant fungi and emergence of secondary resistance as a result of drug-induced selection pressure are of major concern. Echinocandins remain a major component of treatment of invasive candidiasis and new triazoles are the best alternative for prophylaxis and therapy of invasive aspergillosis.

Fungal Pneumonia in Patients with Hematologic Malignancy and Hematopoietic Stem Cell Transplantation

Fungal pneumonias cause unacceptable morbidity among patients with hematologic malignancies (HM) and recipients of hematopoietic stem cell transplantation (HSCT). The high incidence of fungal pneumonias in HM/HSCT populations arises from their frequently severe, complex, and persistent immune dysfunction caused by the underlying disease and its treatment. The cytopenias, treatment toxicities, and other immune derangements that make patients susceptible to fungal pneumonia frequently complicate its diagnosis and increase the intensity and duration of antifungal therapy. This article addresses the host factors that contribute to susceptibility, summarizes diagnostic recommendations, and reviews current guidelines for management of fungal pneumonia in patients with HM/HSCT.

Inducible epithelial resistance protects mice against leukemia-associated pneumonia

Despite widespread infection prevention efforts, pneumonia remains the leading cause of death among patients with acute leukemia, due to complex disease- and treatment-dependent immune defects. We have reported that a single inhaled treatment with a synergistic combination of Toll-like receptor 2/6 (TLR 2/6) and TLR9 agonists (Pam2-ODN) induces protective mucosal defenses in mice against a broad range of pathogens. As Pam2-ODN-induced protection persists despite depletion of several leukocyte populations, we tested whether it could prevent pneumonia in a mouse model of acute myeloid leukemia (AML) remission induction therapy. Pam2-ODN prevented death due to pneumonia caused by Pseudomonas aeruginosa, Streptococcus pneumoniae, and Aspergillus fumigatus when mice were heavily engrafted with leukemia cells, had severe chemotherapy-induced neutropenia or both. Pam2-ODN also extended survival of pneumonia in NSG mice engrafted with primary human AML cells. Protection was associated with rapid pathogen killing in the lungs at the time of infection and with reduced pathogen burdens at distant sites at the end of observation. Pathogen killing was inducible directly from isolated lung epithelial cells and was not abrogated by the presence of leukemia cells or cytotoxic agents. Pam2-ODN had no discernible effect on replication rate, total tumor population, or killing by chemotherapy of mouse or human leukemia cells, either in vitro or in vivo. Taken together, we report that therapeutic stimulation of lung epithelial defenses robustly protects against otherwise lethal pneumonias despite the profound immune dysfunction associated with acute leukemia and its treatment. These findings may suggest an opportunity to protect this population during periods of peak vulnerability.

Pneumonia in the neutropenic cancer patient

PURPOSE OF REVIEW

Pneumonia is the leading cause of death among neutropenic cancer patients, particularly those with acute leukaemia. Even with empiric therapy, case fatality rates of neutropenic pneumonias remain unacceptably high. However, recent advances in the management of neutropenic pneumonia offer hope for improved outcomes in the cancer setting. This review summarizes recent literature regarding the clinical presentation, microbiologic trends, diagnostic advances and therapeutic recommendations for cancer-related neutropenic pneumonia.

RECENT FINDINGS

Although neutropenic patients acquire pathogens both in community and nosocomial settings, patients' obligate healthcare exposures result in the frequent identification of multidrug-resistant bacterial organisms on conventional culture-based assessment of respiratory secretions. Modern molecular techniques, including expanded use of galactomannan testing, have further facilitated identification of fungal pathogens, allowing for aggressive interventions that appear to improve patient outcomes. Multiple interested societies have issued updated guidelines for antibiotic therapy of suspected neutropenic pneumonia. The benefit of antibiotic medications may be further enhanced by agents that promote host responses to infection.

SUMMARY

Neutropenic cancer patients have numerous potential causes for pulmonary infiltrates and clinical deterioration, with lower respiratory tract infections among the most deadly. Early clinical suspicion, diagnosis and intervention for neutropenic pneumonia provide cancer patients' best hope for survival.

Pneumonia in the immunocompromised host

PURPOSE OF REVIEW

Novel treatment modalities for previously fatal diseases, including newer chemotherapeutic and biologic agents and the expansion of the indications for solid organ and stem cell transplantation, have resulted in prolonged patient survival and a significant increase in the population of immunocompromised hosts (ICHs).

RECENT FINDINGS

This review discusses the increasing spectrum of opportunistic infections in the ICH, the general approach for early diagnosis and treatment of pulmonary infections in this population, and the current and novel diagnostic modalities available to establish a rapid and specific microbiologic diagnosis, focusing on recent controversies and advances.

SUMMARY

Early diagnosis and prompt initiation of effective therapy for infection help reduce morbidity in ICHs. Advances in diagnostic assays using nonculture-based methods, such as nucleic acid amplification, may allow for earlier targeted therapy. Invasive procedures including bronchoscopy and biopsy remain essential and should be vigorously pursued in ICHs given the broad differential diagnosis of possible pulmonary pathogens in this population, and the need to establish a specific diagnosis to allow accurate targeted therapy.

Diagnostic methods for invasive fungal diseases in patients with hematologic malignancies

Invasive fungal disease is associated with increased morbidity and mortality in hematologic malignancy patients and hematopoietic stem cell transplant recipients. Timely recognition and treatment of invasive fungal diseases in these patients are essential and decrease mortality. However, conventional definitive diagnostic methods are difficult and time consuming. While conventional microbiological and histopathological methods are still needed for a definitive diagnosis of invasive fungal disease, new noninvasive diagnostic methods including serologic and molecular biomarkers are now available. These new diagnostic methods facilitate an early diagnosis of invasive fungal disease and allow for utilization of a pre-emptive treatment approach, which may ultimately lead to improved treatment outcomes and reduced toxicity.

Bronchoscopy as an indicator of tracheobronchial fungal infection in non-neutropenic intensive-care unit patients

We aimed to establish that a bronchoscopic view can be as reliable as microbiology, and support an empirical tracheobronchial fungal infection (TBFI) treatment decision. We retrospectively studied 95 respiratory failure patients with suspected TBFI admitted to the intensive-care unit (ICU) in 2008 with sticky secretions, hyperaemic mucosa, and whitish plaques on bronchoscopic view. Patients not suspected of having TBFI were chosen as a control group (n = 151). Broncheoalveolar lavage (BAL) fluid was cultured, and biopsy samples were taken from the lesions. Biopsy samples positive for fungi were defined as 'proven', only BAL-positive (+ fungi) cases were 'probable TBFI', and BAL-negative (- fungi) cases were 'possible TBFI'. BAL (+ fungi) and BAL (- fungi) in the control group were defined as 'colonization' and 'no TBFI', respectively. The sensitivity, specificity and positive and negative predictive values of BAL (+ fungi) were 85.1% (63/74), 81.4% (140/172), 66.3% (63/95), and 92.7% (140/151), respectively. Biopsies were performed in 78 of 95 patients, and 28 were proven TBFI with fungal elements, and 100% were BAL (+ fungi). Probable TBFI was seen in 30 of 95 patients with BAL (+ fungi), and possible TBFI (BAL(- fungi)) in 25 of 95. Among the 95 patients, microbiology revealed fungi (90.5% Candida species; 9.5% Aspergillus) in 63 (66.3%). In the controls, the colonization and no TBFI rates were 11 of 151 and 140 of 151, respectively. Observing sticky secretions, hyperaemic mucosa and whitish plaques by bronchoscopy is faster than and may be as reliable as microbiology for diagnosing TBFI. These findings are relevant for empirical antifungal therapy in suspected TBFI patients in the ICU.

Immunity and tolerance to fungi in hematopoietic transplantation: principles and perspectives

Resistance and tolerance are two complementary host defense mechanisms that increase fitness in response to low-virulence fungi. Resistance is meant to reduce pathogen burden during infection through innate and adaptive immune mechanisms, whereas tolerance mitigates the substantial cost of resistance to host fitness through a multitude of anti-inflammatory mechanisms, including immunological tolerance. In experimental fungal infections, both defense mechanisms are activated through the delicate equilibrium between Th1/Th17 cells, which provide antifungal resistance, and regulatory T cells limiting the consequences of the ensuing inflammatory pathology. Indoleamine 2,3-dioxygenase (IDO), a rate-limiting enzyme in the tryptophan catabolism, plays a key role in induction of tolerance against fungi. Both hematopoietic and non-hematopoietic compartments contribute to the resistance/tolerance balance against Aspergillus fumigatus via the involvement of selected innate receptors converging on IDO. Several genetic polymorphisms in pattern recognition receptors influence resistance and tolerance to fungal infections in human hematopoietic transplantation. Thus, tolerance mechanisms may be exploited for novel diagnostics and therapeutics against fungal infections and diseases.

Role of innate immune receptors in paradoxical caspofungin activity in vivo in preclinical aspergillosis

This study investigated the possible mechanisms underlying the paradoxical caspofungin activity in vivo in preclinical aspergillosis. We evaluated the activity of escalating doses of caspofungin in vivo in different preclinical models of invasive aspergillosis, including mice deficient for selected innate immune receptors. The therapeutic efficacy of caspofungin in experimental invasive aspergillosis was strictly dose dependent, being observed at doses of 0.1 and 1 mg/kg of body weight depending on the experimental models. Paradoxical increase in pulmonary fungal burden as well as inflammatory pathology was observed at the highest dose of caspofungin (5 mg/kg), occurred independently of the so-called Eagle effect and susceptibility to caspofungin in vitro, and was contingent upon the presence of TLR2, Dectin-1, and TLR9. Increased expression of Dectin-1 and TLR9 were observed upon exposure to caspofungin in vitro and in vivo. Together, these findings suggest that the net activity of caspofungin in vivo is orchestrated by the activation, directly or indirectly, of multiple innate immune receptors.

The prognostic role of hemochromatosis H63D allele in allogeneic hematopoietic stem cell transplantation

Iron overload is considered as a significant cause of morbidity and mortality in hematopoietic stem cell transplant (HSCT) recipients. The presence of hemochromatosis gene (HFE) mutations might exacerbate iron toxicity in the post-transplant setting. This prospective study was planned to evaluate the genetic spectrum of HFE mutations in Turkish patients undergoing HSCT and the impact of HFE genotype on transplant morbidity and mortality. HFE genotypes of 102 patients [median age, 27.5 years (16-64 years); male/female, 73:29], who underwent allogeneic HSCT, were analyzed. Twenty-two patients were heterozygous and 1 patient was homozygous for the H63D mutation, while the C282Y mutation was observed in none of our patients. The frequency of invasive fungal infections (IFI) was significantly higher in H63D-mutated patients (p=0.004). H63D mutation was identified as an independent risk factor for the development of IFI (p=0.006, OR=0.554, SE=0.208), without an impact on overall survival and transplant-related mortality. The multifactorial iron-overloaded state in HSCT recipients might affect the phenotypic expression of HFE mutations and alter the severity of clinical presentation. The impact of HFE genotype on iron parameters and transplant-related morbidity and mortality should be validated with further studies.