Objectives-To describe first dose and steady state antiretroviral drug exposure in the female genital tract. Design-Non-blinded, single center, open-label pharmacokinetic study in HIV-infected women.Method-Twenty-seven women initiating combination antiretroviral therapy underwent comprehensive blood plasma and cervicovaginal fluid sampling for drug concentrations during the first dose of antiretroviral therapy and at steady-state. Drug concentrations were measured by validated HPLC/UV or HPLC-MS/MS methods. Pharmacokinetic parameters were estimated for 11 drugs by non-compartmental analysis. Descriptive statistics and 95% confidence intervals were generated using Intercooled STATA Release 8.0 (Stata Corporation, College Station, Texas, USA).Results-For all antiretroviral drugs, genital tract concentrations were detected rapidly after the first dose. Drugs were stratified according to the genital tract concentrations achieved relative to blood plasma. Median rank order of highest to lowest genital tract concentrations relative to blood plasma at steady state were: lamivudine (concentrations achieved were 411% greater than blood plasma), emtricitabine (395%), zidovudine (235%) tenofovir (75%), ritonavir (26%), didanosine (21%), atazanavir (18%), lopinavir (8%), abacavir (8%), stavudine (5%), and efavirenz (0.4%).Conclusions-This is the first study to comprehensively evaluate antiretroviral drug exposure in the female genital tract. These findings support the use of lamivudine, zidovudine, tenofovir and emtricitabine as excellent pre-exposure/post-exposure prophylaxis (PrEP/PEP) candidates. Atazanavir and lopinavir might be useful agents for these applications due to favorable therapeutic indices, despite lower genital tract concentrations. Agents such as stavudine, abacavir, and efavirenz that achieve genital tract exposures less than 10% of blood plasma are less attractive PrEP/PEP candidates.

LPV/r therapy results in modest induction of CYP1A2 and CYP2C9 and potent induction of CYP2C19 activity. Increasing doses of concomitant medications metabolized by these enzymes may be necessary. LPV/r inhibited intestinal CYP3A to a greater extent than hepatic CYP3A activity. Doses of concomitant CYP3A substrates should be reduced when combined with LPV/r, although intravenously administered compounds may require less of a relative dose reduction than orally administered compounds.

Daily intravenous (IV) busulfan is increasingly being used in hematopoietic cell transplantation (HCT) conditioning regimens. Intravenous busulfan doses administered at the traditional frequency of every 6 hours can be targeted (TBu) to a patient-specific concentration at steady state (Css) using therapeutic drug monitoring. In this report, we describe our experiences with TDM of daily IV busulfan in an adult population, with the specific aims of 1) evaluating covariates associated with busulfan clearance; 2) assessing the feasibility of therapeutic drug monitoring for outpatient administration of daily TBu with pharmacokinetic sampling over 6 hours. A retrospective pharmacokinetic analysis was conducted in 87 adults receiving daily TBu as part of cyclophosphamide followed by TBU (CY/TBU), fludarabine monophosphate (fludarabine) followed by TBU, or TBU concurrent with fludarabine conditioning. The desired Css was achieved in 85% of patients receiving daily IV busulfan. Busulfan clearance was not associated with gender or age, but was associated with the day of dosing and conditioning regimen (p=0.0016). In patients receiving CY/TBU, no differences in clearance were found between dosing days (p>0.36); however, clearance decreased significantly in patients receiving fludarabine-based regimens (p=0.0016). Busulfan clearance and Css estimates from pharmacokinetic sampling over 8, 11, or 24 hours were comparable (p>0.4). However, pharmacokinetic modeling of individual patient concentration-time data over 6 hours could not reliably estimate busulfan clearance or Css.

PURPOSE Cisplatin is synergistic with vinorelbine and the poly(ADP-ribose) polymerase (PARP) inhibitor veliparib, and has anti-neoplastic activity in TNBC and BRCA mutation-associated breast cancer. This phase I study assessed veliparib with cisplatin and vinorelbine. PATIENTS AND METHODS A 3+3 dose escalation design evaluated veliparib administered BID for 14 days with cisplatin (75 mg/m2 day 1) and vinorelbine (25 mg/m2 days 1,8) every 21 days, for six to ten cycles, followed by veliparib monotherapy. Pharmacokinetics, measurement of poly(ADP-ribose) in peripheral blood mononuclear cells, and preliminary efficacy were assessed. Immunohistochemistry and gene expression profiling were evaluated as potential predictors of response. RESULTS Forty-five patients enrolled in nine dose cohorts plus five in an expansion cohort at the highest dose level and recommended phase II dose, 300 mg BID. Maximum tolerated dose of veliparib was not reached. Neutropenia (36%), anemia (30%), and thrombocytopenia (12%) were the most common grade 3/4 adverse events. Best overall response for 48 patients was radiologic response with 9-week confirmation for 17 (35%; 2 complete, 15 partial), and stable disease for 21 (44%). Germline BRCA mutation presence versus absence was associated with 6-month progression-free survival (10 of 14 (71%) vs 8 of 27 (30%), mid-p=0.01). Median progression-free survival for all 50 patients was 5.5 months (95% confidence interval 4.1–6.7). CONCLUSION Veliparib at 300 mg BID combined with cisplatin and vinorelbine is well tolerated with encouraging response rates. A phase II randomized trial is planned to assess veliparib’s contribution to cisplatin chemotherapy in metastatic TNBC and BRCA mutation-associated breast cancer. Translational Relevance We hypothesize that TNBC tumors have defects in homologous recombination DNA repair similar to BRCA mutation associated tumors, which will render them sensitive to platinum therapy and PARP inhibition. This report describes a phase I study that explored the safety and efficacy of cisplatin, vinorelbine and veliparib. This combination was tolerable and reached the highest dose of veliparib in combination with chemotherapy used in breast cancer to date. Antineoplastic activity was observed both in BRCA mutation associated breast cancer and in BRCA wild-type TNBC. We measured changes in PARP activity and performed gene expression profiling and immunohistochemistry studies. Based on promising results from this study, a randomized phase II study has been developed to evaluate the addition of veliparib to cisplatin chemotherapy for patients with advanced TNBC. This study will incorporate a multi-pronged biomarker approach to identify a homologous recombination repair deficiency (HRD) phenotype that derives benefit from PARP inhibition.