Clinically defined chemotherapy-associated bowel syndrome predicts severe complications and death in cancer patients

Phase 1b/3 Pharmacokinetics and Safety Study of Intravenous Posaconazole in Adult Asian Participants at High Risk for Invasive Fungal Infections

Introduction

Antifungal prophylaxis in patients at high risk for invasive fungal infections (IFIs), such as those with acute myeloid leukemia or myelodysplastic syndromes, continues to be underused in Asia, despite the fact that it reduces IFI-related death and increases IFI-free survival. We characterized the pharmacokinetics (PK) and safety of the intravenous (IV) formulation of posaconazole in adult Asian participants at high risk for IFI.

Methods

Participants received posaconazole IV 300 mg twice on day 1, posaconazole IV 300 mg once daily on days 2–10, and posaconazole IV 300 mg once daily or oral suspension 200 mg 3 times daily for up to 18 days for a maximum of 28 days. There were two PK sampling groups: intensive and sparse. Sparse trough PK sampling was collected from all participants on days 3, 6, 10, 15, 22, and 28/end of treatment. The intensive PK group had additional sampling performed over 24 h on day 10. Primary end points were steady state average concentration (C_avg,ss) and percentage of participants with C_avg,ss ≥ 500 ng/mL. Safety was assessed up to day 30/end of treatment.

Results

Seventy participants with acute myelogenous leukemia were enrolled, 30 in the intensive PK group and 40 in the sparse PK group; 57 participants completed the study, 26 in the intensive PK group and 31 in the sparse PK group. On day 10, arithmetic mean C_avg,ss was 2986 ng/mL [coefficient of variation (%CV), 36%; range, 1409–5930 ng/mL]; 100% of participants in the intensive PK group (n/N = 27/27) had C_avg,ss ≥ 500 ng/mL. Arithmetic mean (%CV) C_min was 2474 (50.4%) and 2466 ng/mL (42.4%) in the intensive and sparse PK groups on day 10, respectively. Safety was similar to that of previous posaconazole formulations.

Conclusion

In Asian participants at high risk for IFIs, IV posaconazole achieved the target exposure associated with efficacy that was previously established for supporting global registration of posaconazole for IV administration and was generally well tolerated.

Clinical trial registration

ClinicalTrials.gov, NCT03336502.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-02012-1.

Vancomycin-resistant Enterococcus faecium COLONIZATION and Clostridium difficile infection in a HEMATOLOGIC patient

Vancomycin-resistant enterococci (VRE), especially Enterococcus faecium, have emerged as significant nosocomial pathogens and patients with impaired host defenses are at a particular risk of VRE infection. The most common occurrence is asymptomatic colonization of the gastrointestinal tract that can persist for a long time and serve as a reservoir for transmission of VRE to other patients. We present a case of a patient who was diagnosed with acute myelogenous leukemia and suffered from bone marrow aplasia following induction therapy. The patient received prolonged broad-spectrum antimicrobial therapy. During hospital stay, the patient developed Clostridium difficile infection (CDI) and was found to be colonized with a strain of Enterococcus faecium resistant to vancomycin during therapy for CDI. This case also highlights the role of risk factors that could contribute to development of resistance, particularly CDI. Early detection of VRE colonization or infection is a crucial component in hospital program designed to prevent transmission of nosocomial infections. Surveillance cultures of such patients should be mandatory.

Pharmacokinetics and Safety of Posaconazole Tablet Formulation in Chinese Participants at High Risk for Invasive Fungal Infection

INTRODUCTION

This study characterized the multidose pharmacokinetic (PK) characteristics of posaconazole tablets used as prophylactic antifungal therapy in Chinese patients with acute myelogenous leukemia (AML) at risk for invasive fungal infection (IFI).

METHODS

Participants in this open-label, single-arm, phase 1b study received posaconazole 300 mg twice daily on day 1 and then once daily for up to 28 days. In the intensive PK sampling subgroup, posaconazole was administered under fasting conditions on days 1 and 8, and blood samples were regularly collected over 24 h. Trough PK sampling was conducted in all participants on days 1, 2, 3, 8, 14, 21, and 28 without regard for food intake. Population PK characteristics were predicted using PK modeling. Primary endpoints were steady-state average concentration (C_avg) and percentage of participants with steady-state C_avg (predicted and observed) > 500 ng/ml. Treatment safety and efficacy were secondary endpoints.

RESULTS

Sixty-five adult Chinese participants were enrolled. On day 8, steady-state arithmetic mean C_avg was 1610 ng/ml (% coefficient of variation [%CV] 42.8%) in the intensive PK subgroup (n = 20). All participants achieved a steady-state C_avg > 500 ng/ml. Predicted C_avg (pC_avg) was 1770 ng/ml (%CV 33.7%) in the total population (n = 64); 92.2% of participants had pC_avg values ≥ 500 ng/ml (n = 59). The posaconazole tablet safety profile was consistent with that of the oral formulation, and the IFI rate was 3%.

CONCLUSION

In Chinese AML patients, the posaconazole 300-mg tablet provided PK data comparable with those of previous studies and was generally well tolerated and efficacious.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT02387983.

Pharmacokinetics and Safety of Posaconazole Administered by Intravenous Solution and Oral Tablet in Healthy Chinese Subjects and Effect of Food on Tablet Bioavailability

BACKGROUND AND OBJECTIVES

New intravenous and solid oral formulations of the antifungal agent posaconazole have been developed. This randomized, open-label, crossover study in 18 healthy adult Chinese male and female subjects evaluated the pharmacokinetics of single-dose posaconazole (oral 300-mg posaconazole tablet fasted, intravenous 300-mg posaconazole solution fasted, and oral 300-mg posaconazole tablet with standard high-fat breakfast). Primary objectives were to determine the single-dose pharmacokinetics of posaconazole in healthy Chinese subjects when administered as an intravenous solution and as an oral tablet under fasted conditions and the effect of food on the absorption of posaconazole.

METHODS

The three treatments consisted of the following: a single oral dose of posaconazole 300 mg (fasted), a single oral dose of posaconazole 300 mg (high-fat breakfast), and a single intravenous dose of posaconazole 300 mg (fasted). Blood samples for pharmacokinetic analysis were collected before dosing and at regular intervals after dosing. Adverse events were monitored throughout. The pharmacokinetic population included the per-protocol population. The safety population included all subjects who received one or more doses of the study drug.

RESULTS

Time to maximum plasma concentration of intravenous posaconazole coincided with the end of infusion; the half-life (t½) was 25.76 h. Geometric mean (% coefficient of variation) values of area under the plasma concentration-time curve from time 0 extrapolated to infinity (AUC_0-∞) and maximum plasma concentration (C_max) were 59,925 (36.2%) h·ng/mL and 3999 (28.5%) ng/mL, respectively. The posaconazole tablet had a time to maximum plasma concentration of 4 h and a t½ of 25.21 h after fasting. Geometric mean (coefficient of variation) values of AUC_0-∞ and C_max were 25,263 (39.9%) h·ng/mL and 674.5 (29.6%) ng/mL, respectively. Standard high-fat breakfast increased the exposure of posaconazole approximately twofold with geometric mean ratios (high-fat breakfast/fasted) for AUC_0-∞ and C_max of 2.06 (90% confidence interval 1.86-2.30) and 1.95 (90% confidence interval 1.65-2.31), respectively. The geometric mean absolute bioavailability of the tablet formulation was 42.2% in the fasted state and 87.1% under high-fat breakfast conditions. The most commonly reported adverse events were nausea, vomiting, dizziness, and first-degree atrioventricular block for intravenous posaconazole 300 mg and nausea for oral posaconazole 300 mg (high-fat breakfast). All adverse events were mild and resolved without sequelae.

CONCLUSIONS

Posaconazole was generally well tolerated in healthy Chinese male and female subjects. The safety and the high-fat breakfast and fasted pharmacokinetics of posaconazole in healthy Chinese subjects are within exposures demonstrated to be generally well tolerated and efficacious and compare reasonably well with the overall posaconazole data across Western countries.

Cost-effectiveness of posaconazole tablets versus fluconazole as prophylaxis for invasive fungal diseases in patients with graft-versus-host disease after allogeneic hematopoietic stem cell transplantation

BACKGROUND

The cost-effectiveness of posaconazole oral suspension versus fluconazole capsules for the prophylaxis of invasive fungal diseases (IFDs) in immunosuppressed allogeneic hematopoietic stem cell transplantation (HSCT) recipients has already been proven. Now, a new solid oral tablet formulation for posaconazole has been developed with improved bioavailability, allowing a reduced daily dosage that can be taken independently of food intake. However, the efficacy of this new formulation should be evaluated since it is associated with a higher cost than the posaconazole oral suspension.

OBJECTIVES

To evaluate the cost-effectiveness of solid oral tablets of posaconazole versus fluconazole capsules for the prophylaxis of IFDs in allogeneic HSCT recipients with graft-versus-host disease (GVHD) in Spain.

METHODOLOGY

A mathematical model comparing the efficacy and costs of posaconazole versus fluconazole was adapted to the Spanish National Healthcare System. Clinical data were obtained from the pivotal clinical trial of posaconazole oral suspension for allogeneic HSCT recipients, while pharmacological costs and use of resources were obtained from national sources. Deterministic and probabilistic sensitivity analyses (PSA), as well as two alternative scenarios, were run to evaluate the robustness of the results under varying input values.

RESULTS

Posaconazole tablets reduced the number of IFD events and enhanced overall survival, while maintaining a controlled budget. When compared to fluconazole, it was found to be a cost-effective alternative, with an incremental cost-effectiveness ratio of €13,193/life years gained. The PSA showed that posaconazole remained cost-effective in 74.6% of the cases, while alternatives scenarios yielded similar results as the base case.

CONCLUSIONS

Posaconazole tablets are a cost-effective alternative to fluconazole and may show better results than the oral suspension formulation.

Identification of potential urine proteins and microRNA biomarkers for the diagnosis of pulmonary tuberculosis patients

This study identified urinary biomarkers for tuberculosis (TB) diagnosis. The urine proteomic profiles of 45 pulmonary tuberculosis patients prior to anti-TB treatment and 45 healthy controls were analyzed and compared using two-dimensional electrophoresis with matrix-assisted laser desorption/ionization time of flight mass spectrometry. Nineteen differentially expressed proteins were identified preliminarily, and western blotting and qRT-PCR were performed to confirm these changes at the translational and transcriptional levels, respectively, using samples from 122 additional pulmonary tuberculosis patients and 73 additional healthy controls. Two proteins, mannose-binding lectin 2 and a 35-kDa fragment of inter-α-trypsin inhibitor H4, exhibited the highest differential expression. We constructed a protein-microRNA interaction network that primarily involved complement and inflammatory responses. Eleven microRNAs from microRNA-target protein interactions were screened and validated using qRT-PCR with some of the above samples, including 97 pulmonary tuberculosis patients and 48 healthy controls. Only miR-625-3p exhibited significant differential expression (p < 0.05). miR-625-3p was increased to a greater extent in samples of smear-positive than smear-negative patients. miR-625-3p was predicted to target mannose-binding lectin 2 protein. A binary logistic regression model based on miR-625-3p, mannose-binding lectin 2, and inter-α-trypsin inhibitor H4 was further established. This three-biomarker combination exhibited better performance for tuberculosis diagnosis than individual biomarkers or any two-biomarker combination and generated a diagnostic sensitivity of 85.87% and a specificity of 87.50%. These novel urine biomarkers may significantly improve tuberculosis diagnosis.

Diagnosis and management of gastrointestinal complications in adult cancer patients: 2017 updated evidence-based guidelines of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Medical Oncology (DGHO)

Cancer patients frequently suffer from gastrointestinal complications. In this manuscript, we update our 2013 guideline on the diagnosis and management of gastrointestinal complications in adult cancer patients by the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Medical Oncology (DGHO). An expert group was put together by the AGIHO to update the existing guideline. For each sub-topic, a literature search was performed in PubMed, Medline, and Cochrane databases, and strengths of recommendation and the quality of the published evidence for major therapeutic strategies were categorized using the 2015 European Society for Clinical Microbiology and Infectious Diseases (ESCMID) criteria. Final recommendations were approved by the AGIHO plenary conference. Recommendations were made with respect to non-infectious and infectious gastrointestinal complications. Strengths of recommendation and levels of evidence are presented. A multidisciplinary approach to the diagnosis and management of gastrointestinal complications in cancer patients is mandatory. Evidence-based recommendations are provided in this updated guideline.

Efficacy of antineoplastic treatment is associated with the use of antibiotics that modulate intestinal microbiota

Reduced anticancer efficacy of cyclophosphamide and platinum salts has been reported in animals treated with anti-Gram-positive antibiotics. These effects were related to translocation of Gram-positive bacteria during mucositis with subsequent induction of cytotoxic oxygen reactive species and tumor invasion by pathogenic Th17 cells. To assess these hypotheses in a clinical setting, we identified patients receiving cyclophosphamide for chronic lymphocytic leukemia (CLL) and cisplatin for relapsed lymphoma. Data originated from the CLL8 trial (NCT00281918) and the Cologne Cohort of Neutropenic Patients (NCT01821456). Relevant antibiotics were defined as compounds with primary activity against Gram-positive bacteria. We evaluated their impact on response, progression-free survival (PFS) and overall survival (OS) by Kaplan-Meier methodology and Cox proportional hazards regression analysis. Among 800 available CLL patients, those receiving anti-Gram-positive antibiotics (n = 45/800) achieved a significantly lower overall response rate (OR 74.3% vs. 90.2%, p = 0.007). Patients with anti-Gram-positive antibiotics progressed significantly earlier, had a reduced OS (median PFS 14.1 vs. 44.1 mo, p < 0.001; median OS 56.1 vs. 91.7 mo, p < 0.001) and multivariate analysis showed that administration of anti-Gram-positive antibiotic treatment was independently associated with reduced PFS (Hazard ratio (HR) 2.090, p = 0.001) and OS (HR 2.966, p < 0.001). Of 122 patients with relapsed lymphoma, those treated with anti-Gram-positive antibiotics (n = 21/122) achieved a significantly lower OR rate (70.3% vs. 42.9%, p = 0.016). Patients with anti-Gram-positive antibiotics progressed significantly earlier than others (median PFS 2.3 vs. 11.5 mo, p = 0.001). As for multivariate analysis, the use of anti-Gram-positive antibiotics was independently associated with reduced PFS (HR 2.237, p = 0.012) and OS (HR 7.831, p < 0.001). Our data supports a potential negative impact of anti-Gram-positive antibiotics on the anticancer activity of cyclophosphamide and cisplatin in a clinical setting.

Phase 3 pharmacokinetics and safety study of a posaconazole tablet formulation in patients at risk for invasive fungal disease

BACKGROUND

Antifungal prophylaxis with a new oral tablet formulation of posaconazole may be beneficial to patients at high risk for invasive fungal disease. A two-part (Phase 1B/3) study evaluated posaconazole tablet pharmacokinetics (PK) and safety.

METHODS

Patients with neutropenia following chemotherapy for haematological malignancy or recipients of allogeneic HSCT receiving prophylaxis or treatment for graft-versus-host disease received 300 mg posaconazole (as tablets) once daily (twice daily on day 1) for up to 28 days without regard to food intake. Weekly trough PK sampling was performed during therapy, and a subset of patients had sampling on days 1 and 8. Cmin-evaluable subjects received ≥6 days of dosing, and were compliant with specified sampling timepoints. Steady-state PK parameters, safety, clinical failure and survival to day 65 were assessed. ClinicalTrials.gov, NCT01777763; EU Clinical Trials Register, EUDRA-CT 2008-006684-36.

RESULTS

Two hundred and ten patients received 300 mg posaconazole (as tablets) once daily. Among Cmin-evaluable subjects (n = 186), steady-state mean Cmin was 1720 ng/mL (range = 210-9140). Steady-state Cmin was ≥700 ng/mL in 90% of subjects with 5% (10 of 186) <500 ng/mL and 5% (10 of 186) 500-700 ng/mL. Six (3%) patients had steady-state Cmin ≥3750 ng/mL. One patient (<1%) had an invasive fungal infection. The most common treatment-related adverse events were nausea (11%) and diarrhoea (8%). There was no increase in adverse event frequency with higher posaconazole exposure.

CONCLUSIONS

In patients at high risk for invasive fungal disease, 300 mg posaconazole (as tablets) once daily was well tolerated and demonstrated a safety profile similar to that reported for posaconazole oral suspension: most patients (99%) achieved steady-state pCavg exposures >500 ng/mL and only one patient (<1%) had a pCavg <500 ng/mL.

Incidence of diarrhea by Clostridium difficile in hematologic patients and hematopoietic stem cell transplantation patients: risk factors for severe forms and death

We describe the rate of incidence of Clostridium difficile-associated diarrhea (CDAD) in hematologic and patients undergone stem cell transplant (HSCT) at HC-FMUSP, from January 2007 to June 2011, using two denominators 1,000 patient and 1,000 days of neutropenia and the risk factors associated with the severe form of the disease and death. The ELISA method (Ridascreen-Biopharm, Germany) for the detections of toxins A/B was used to identify C. difficile. A multivariate analysis was performed to evaluate potential factors associated with severe CDAD and death within 14 days after the diagnosis of CDAD, using multiple logistic regression. Sixty-six episodes were identified in 64 patients among 439 patients with diarrhea during the study period. CDA rate of incidence varied from 0.78 to 5.45 per 1,000 days of neutropenia and from 0.65 to 5.45 per 1,000 patient-days. The most common underlying disease was acute myeloid leukemia 30/64 (44%), 32/64 (46%) patients were neutropenic, 31/64 (45%) undergone allogeneic HSCT, 61/64 (88%) had previously used antibiotics and 9/64 (13%) have severe CDAD. Most of the patients (89%) received treatment with oral metronidazole and 19/64 (26%) died. The independent risk factors associated with death were the severe form of CDAD, and use of linezolid.

Phase 1b study of new posaconazole tablet for prevention of invasive fungal infections in high-risk patients with neutropenia

Posaconazole tablets, a new oral formulation of posaconazole, can be effective when given as antifungal prophylaxis to neutropenic patients at high risk for invasive fungal infection (e.g., those with acute myelogenous leukemia or myelodysplastic syndrome). Such effectiveness might be specifically important to patients with poor oral intake because of nausea, vomiting, or chemotherapy-associated mucositis. This was a prospective, global study in high-risk patients to characterize the pharmacokinetics and safety profile of posaconazole tablets and to identify the dose of posaconazole tablets that would provide exposure within a predefined range of exposures (steady-state average concentration [area under the concentration-time curve/24 h] of ≥500 ng/ml and ≤2,500 ng/ml in >90% of patients). The study evaluated two sequential dosing cohorts: 200 mg posaconazole once daily (n = 20) and 300 mg posaconazole once daily (n = 34) (both cohorts had a twice-daily loading dose on day 1) taken without regard to food intake during the neutropenic period for ≤28 days. The exposure target was reached (day 8) in 15 of 19 (79%) pharmacokinetic-evaluable patients taking 200 mg posaconazole once daily and in 31 of 32 (97%) patients taking 300 mg posaconazole once daily; 300 mg posaconazole once daily achieved the desired exposure target. Posaconazole tablets were generally well tolerated in high-risk neutropenic patients. (This study has been registered at ClinicalTrials.gov under registration no. NCT01777763.).

Posaconazole tablet pharmacokinetics: lack of effect of concomitant medications altering gastric pH and gastric motility in healthy subjects

Posaconazole oral suspension is an extended-spectrum triazole that should be taken with food to maximize absorption. A new posaconazole tablet formulation has demonstrated improved bioavailability over the oral suspension in healthy adults in a fasting state. This study evaluated the effects of concomitant medications altering gastric pH (antacid, ranitidine, and esomeprazole) and gastric motility (metoclopramide) on the pharmacokinetics of posaconazole tablets. This was a prospective open-label 5-way crossover study in 20 healthy volunteers. In each treatment period, a single 400-mg dose (4 100-mg tablets) of posaconazole was administered alone or with 20 ml antacid (2 g of aluminum hydroxide and 2 g of magnesium hydroxide), ranitidine (150 mg), esomeprazole (40 mg), or metoclopramide (15 mg). There was a ≥ 10-day washout between treatment periods. Posaconazole exposure, time to maximum concentration of drug in serum (Tmax), and apparent terminal half-life (t1/2) were similar when posaconazole was administered alone or with medications affecting gastric pH and gastric motility. Geometric mean ratios (90% confidence intervals [CIs]) of the area under the concentration-time curve from time zero to infinity (AUC0-inf) (posaconazole with medications affecting gastric pH and gastric motility versus posaconazole alone) were 1.03 (0.88-1.20) with antacid, 0.97 (0.84-1.12) with ranitidine, 1.01 (0.87-1.17) with esomeprazole, and 0.93 (0.79-1.09) with metoclopramide. Geometric mean ratios (90% CIs) of the maximum concentration of drug in serum (Cmax) were 1.06 (0.90-1.26) with antacid, 1.04 (0.88-1.23) with ranitidine, 1.05 (0.89-1.24) with esomeprazole, and 0.86 (0.73-1.02) with metoclopramide. In summary, in healthy volunteers, the pharmacokinetics of a single 400-mg dose of posaconazole tablets was not altered to a clinically meaningful extent when posaconazole was administered alone or with medications affecting gastric pH or gastric motility.

Risk factors, preemptive therapy, and antiperistaltic agents for Clostridium difficile infection in cancer patients

BACKGROUND

Clostridium difficile infection (CDI) is a serious complication of chemotherapy including high-dose regimens with autologous stem cell transplantation (ASCT). Antiperistaltic agents are contraindicated in CDI and preemptive CDI therapy is not recommended. We assessed the incidence, risk factors, and outcomes of CDI in patients with newly diagnosed multiple myeloma (MM) receiving similar antineoplastic therapy and supportive care including antiperistaltic agents and preemptive CDI antibiotics for significant diarrhea.

METHODS

A total of 303 consecutive MM patients (2004-2007) were enrolled in a protocol consisting of induction chemotherapy, tandem melphalan (MEL)-ASCT, and consolidation. Patients with grade 2-4 diarrhea were simultaneously tested for CDI, and initiated on antiperistaltic agents (loperamide) and preemptive anti-CDI therapy. Risk factors, including prior CDI and MM immunoglobulin (Ig) isotype, were evaluated. Multinomial logistic regression was used to compute the relative risk ratio (RRR) and 95% confidence intervals (CIs).

RESULTS

There were 43 cases of CDI (14.2%) during 1529 chemotherapy courses (536 ASCT). IgA MM protected against CDI (RRR 0.35; 95% CI 0.13-0.93, P = 0.04) whereas CDI during first induction markedly increased the risk of recurrence during second induction (RRR = 10.94; 95% CI 1.90, 62.92, P = 0.01) and following MEL-ASCT (RRR = 6.63; 95% CI 1.51, 29.12, P = 0.01). No CDI-related surgical intervention or death ensued despite use of antiperistaltic agents.

CONCLUSIONS

CDI was not uncommon in cancer patients receiving chemotherapy. IgA myeloma appears to be protective. Concurrent antiperistaltic (loperamide) and preemptive CDI therapies were associated with excellent outcomes. Prior CDI history increased the risk for recurrence during successive chemotherapy courses.

Diagnosis and management of gastrointestinal complications in adult cancer patients: evidence-based guidelines of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Oncology (DGHO)

BACKGROUND

Cancer patients frequently suffer from gastrointestinal complications. However, a comprehensive, practical and evidence-based guideline on this issue is not yet available.

PATIENTS AND METHODS

An expert group was put together by the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Oncology (DGHO) to develop a guideline on gastrointestinal complications in cancer patients. For each subtopic, a literature search was carried out in PubMed, Medline and Cochrane databases and the strength of recommendation and the quality of the published evidence for major therapeutic strategies were categorized using a modification of the 'Infectious Diseases Society of America' criteria. Consensus discussions were held on each of the topics.

RESULTS

Recommendations were made with respect to non-infectious and infectious gastrointestinal complications. For all recommendations, the strength of the recommendation and the level of evidence are presented.

CONCLUSION

This guideline is an evidence-based approach to the diagnosis and management of gastrointestinal complications in cancer patients.

Pharmacokinetics of different dosing strategies of oral posaconazole in patients with compromised gastrointestinal function and who are at high risk for invasive fungal infection

The aim of this study was to assess different dosing strategies that may result in increased posaconazole bioavailability in patients with compromised gastrointestinal function and at high risk for invasive fungal infections. Patients undergoing chemotherapy and at risk for compromised gastrointestinal function received open-label posaconazole at 200 mg three times daily (TID) on days 1 to 8. Patients were randomized to one of three open-label dosing regimens of posaconazole on days 9 to 15: 200 mg TID, 400 mg twice daily (BID), or 400 mg TID. The plasma concentrations of interest on days 8 and 15 were 500 and 700 ng/ml, respectively; day 2 plasma concentrations of 250 and 350 ng/ml were chosen as levels that might result in steady-state concentrations of >500 and >700 ng/ml, respectively. A total of 75 patients enrolled; 52/75 (69%) completed the study, and 49/75 were included in the pharmacokinetic analyses. Mean plasma concentrations were 230, 346, and 637 ng/ml on days 2, 3, and 8, respectively. The day 15 values were 660, 930, and 671 ng/ml for 200 mg TID, 400 mg BID, and 400 mg TID, respectively. In 12 patients with a day 8 posaconazole concentration of <250 ng/ml, an overall benefit of the higher two doses was not apparent, suggesting that a subset of patients has low steady-state plasma concentrations. A change in dosing regimen on day 9 did not lead to higher exposures in these "poor absorbers" on day 15. Poor absorption may be enhanced with a high-fat meal, a nutritional supplement, or acidification.