Antiviral Therapy 2014; 19: (doi: /IMP2718)

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1 Antiviral Therapy 2014; 19: (doi: /IMP2718) Original article Effect of the coadministration of daclatasvir on the pharmacokinetics of a combined oral contraceptive containing ethinyl estradiol and norgestimate Marc Bifano 1 *, Heather Sevinsky 1, Carey Hwang 2, Hamza Kandoussi 3, Hao Jiang 3, Dennis Grasela 1, Richard Bertz 1 1 Research and Development, Bristol Myers Squibb, Hopewell, NJ, USA 2 Research and Development, Bristol Myers Squibb, Princeton, NJ, USA 3 Research and Development, Bristol Myers Squibb, Lawrenceville, NJ, USA *Corresponding author marc.bifano@bms.com Background: Daclatasvir is a highly selective NS5A replication complex inhibitor currently in development for the treatment of chronic hepatitis C infection. Daclatasvir is active at picomolar concentrations and demonstrates in vitro activity against a broad range of HCV genotypes. The primary objective of this study was to assess the effect of daclatasvir on the pharmacokinetics of a combined oral contraceptive containing ethinyl estradiol and norgestimate (Ortho Tri-Cyclen ). Methods: In this open-label single-sequence study, 20 healthy female subjects received ethinyl estradiol and norgestimate for three cycles, with coadministration of daclatasvir in cycle 3. Pharmacokinetics of ethinyl estradiol and the active metabolites of norgestimate (norelgestromin and norgestrel) were assessed in cycles 2 and 3. Results: Adjusted ratios of geometric means and 90% CIs were estimated for the maximum observed plasma concentration (ethinyl estradiol 1.11 [1.02, 1.20], norelgestromin 1.06 [0.99, 1.14] and norgestrel 1.07 [0.99, 1.16]) and area under the plasma concentration time curve in one dosing interval (ethinyl estradiol 1.01 [0.95, 1.07], norelgestromin 1.12 [1.06, 1.17] and norgestrel 1.12 [1.02, 1.23]). Conclusions: Coadministration of daclatasvir resulted in no clinically relevant effects on exposure to ethinyl estradiol, norelgestromin or norgestrel. Introduction Up to 170 million individuals are chronically infected with HCV worldwide [1]. Chronic HCV infection is a common cause of chronic progressive liver disease and hepatocellular carcinoma [2]. Until recently, treatment with pegylated interferon (PEG-IFN)-a and the nucleoside analogue ribavirin (RBV) was the standard of care in the management of chronic HCV infection. However, sustained virological response (SVR) rates with this regimen vary depending on viral load, HCV genotype, patient demographics, disease history and host genetics. Although SVR rates of 80% can be achieved in previously treatment-naive patients with HCV genotype 2 or 3 [3,4], SVR rates are lower among those with HCV genotype 1 (40 50%) [5], and in patients with prior nonresponse to PEG-IFN-a/RBV (6 9%). PEG-IFN-a/RBV treatment is also associated with significant haematologic toxicity and frequent side effects, such as flu-like symptoms, haemolytic anaemia, fatigue and depression [4]. The recent introduction of the HCV non-structural protein 3 (NS3) protease inhibitors, telaprevir and boceprevir, which are approved for use in combination with PEG-IFN-a/RBV for the treatment of chronic HCV genotype 1 infection, has significantly improved SVR rates in treatment-naive patients with HCV genotype 1 infection to approximately 70 75% [6,7]. However, both of these direct-acting antivirals increase the frequency and/or severity of adverse events (AEs) compared with that observed with PEG-IFN-a/RBV treatment alone. Boceprevir is associated with increased rates of anaemia and dysgeusia [8], and telaprevir with elevated rates of rash, pruritis, nausea and anaemia [9]. In addition to their clinical AE profiles, both boceprevir and telaprevir are substrates and significant inhibitors of cytochrome (CY) P450 3A (CYP3A), and are known (telaprevir) or inferred (boceprevir) to be substrates and inhibitors of the P-glycoprotein 1 (PgP) 2014 International Medical Press (print) (online) 511

2 M Bifano et al. transporter [10]. As a result, both drugs are associated with a number of pharmacokinetic interactions with concomitant medications, and are contraindicated for use with CYP3A substrates, for which elevated systemic exposure is associated with an increased risk of serious AEs [8,9]. For example, telaprevir has been shown to increase the maximum observed plasma concentration ( ) and area under the plasma concentration time curve (AUC) of both cyclosporine and tacrolimus when coadministered in healthy subjects as a result of telaprevir-induced CYP3A4 inhibition [11]. In addition, telaprevir and boceprevir have also been shown to reduce exposure to a number of drugs by increasing their metabolism, thus resulting in reduced efficacy [8,9]. One such pharmacokinetic interaction noted for both telaprevir and boceprevir is a reduction of ethinyl estradiol (EE) levels when taken with hormonal contraceptives, and, as a result, a warning has been issued for both drugs advising that hormonal contraception may be unreliable during (and, in the case of telaprevir, for up to 2 weeks after) treatment [8,9]. EE and norgestimate (NGM; Ortho Tri-Cyclen, Ortho-McNeil Pharmaceutical Inc., Raritan, NJ, USA) is a commonly prescribed combination oral contraceptive containing EE and the synthetic progestin NGM, which is converted in vivo to its active metabolites norelgestromin (NGMN) and norgestrel (NG). EE is subject to extensive first-pass metabolism in both the gut and the liver, with sulfate conjugation via sulfotransferase 1E1 in the gut, contributing to approximately 60% of the first-pass effect. Once absorbed, EE is also hydroxylated by CYP3A4 and CYP2C9, with CYP2C8, CYP2C19 and CYP1A2 contributing to a lesser extent [12 14], and is glucuronidated by uridine diphosphate glucuronyltransferase (UGT) 1A1 [15]. The basis of the interaction between EE and telaprevir or boceprevir is not fully understood, but may be a multifactorial effect resulting from alterations in CYP450 activity, direct or indirect effects on UGT or sulfation, or alterations in gastrointestinal transport mechanisms. The enzymes responsible for the metabolism of NGM and its active metabolites have not been fully characterized, but it is thought that both CYP3A4 and UGTs may also be involved. The significant teratogenicity of RBV (a pregnancy category X drug) renders it contraindicated for use in pregnancy and makes effective contraception vital in women of childbearing potential who are undergoing PEG-IFN-a/RBV-containing treatment for chronic HCV infection. Thus the effects of telaprevir and boceprevir on EE-based contraceptives necessitate the use of two non-hormonal methods while the interaction is still in effect [8,9]. A number of other direct-acting antivirals for chronic HCV infection are in clinical development. Among them is daclatasvir (DCV; BMS ), which is a highly selective, first-in-class inhibitor of HCV NS5A, an essential component of the HCV replication complex [16,17]. DCV inhibits multiple functions of NS5A, which may explain its potent antiviral effect in vitro; DCV is active at picomolar concentrations and demonstrates in vitro activity against a broad range of HCV genotypes [18]. DCV has previously demonstrated rapid virological suppression, high SVR rates and good tolerability in combination with PEG-IFN-a/RBV among treatment-naive patients with HCV genotype 1 [19]. Clinical efficacy with DCV has also been observed in combination with asunaprevir, an NS3 protease inhibitor and the non-nucleoside inhibitor BMS [20], as well as in combination with the nucleotide inhibitor sofosbuvir (GS-7977) with and without RBV [21]. High SVR rates are also achievable in HCV genotype 1b patients with a prior null response to PEG-IFN-a/RBV when DCV is used in combination with asunaprevir [22,23]. Preclinical data indicate that DCV is a substrate and inhibitor of PgP and a substrate for CYP3A4; in vivo studies with the CYP3A4 probe substrate midazolam suggest that DCV is unlikely to alter the pharmacokinetics of CYP3A4 substrates (Bristol Myers Squibb, unpublished data). Therefore, unlike telaprevir and boceprevir, DCV has a lower potential for causing drug drug interactions with drugs that are metabolized via the CYP450 pathway. We herein describe a study evaluating the steady-state pharmacokinetic effects of DCV (60 mg once daily) on the active components (EE, NGMN and NG) of a concomitant combined oral contraceptive in healthy female volunteers, along with the tolerability and safety of this drug combination. Methods Study design This was an open-label, three-cycle (lead-in cycle [cycle 1], cycle 2 and cycle 3), single sequence study in 20 healthy women of childbearing potential (clinicaltrials.gov identifier NCT ; Figure 1). Screening evaluations were undertaken to determine eligibility within 28 days prior to the start of the lead-in cycle (day 1). The evening prior to dosing (day 1), subjects were admitted to the clinical facility and underwent baseline evaluations. On day 1, subjects entered the lead-in cycle to ensure compliance and to synchronize subjects to the same dosing schedule. The lead-in cycle and cycle 2 consisted of a standard dosing schedule: daily administration in a 4-week (3 weeks on, 1 week off) cycle, in which the EE dose remains constant at 35 mg while NGM is given on an ascending dose schedule of 180 mg during week 1, 215 mg during week 2 and 250 mg during week 3. The International Medical Press

3 Pharmacokinetics of daclatasvir and an oral contraceptive Figure 1. Study design Treatment A: Days 1 28 Lead-in cycle (Cycle 1) Treatment B: Days Cycle 2 PK sampling on day 49 for 24 h Treatment C: Days DCV 60 mg once daily (Days only) Cycle 3 PK sampling on day 77 for 24 h Subjects received a combined oral contraceptive on days 1 28 (lead-in cycle; treatment period A), days (cycle 2; treatment period B) and days (cycle 3; treatment period C), with daclatasvir (DCV) coadministration on days , ethinyl estradiol and norgestimate; PK, pharmacokinetic. final study cycle (cycle 3) spanned only the 3 weeks of active dosing. During this cycle, DCV was administered for 10 days in combination with EE/ NGM during days DCV was dosed at 60 mg once daily, the highest anticipated therapeutic dose. A dose of 60 mg DCV was based on previous clinical experience and is within the projected therapeutic range known to be well tolerated. Pharmacokinetic sampling was undertaken on the last day of active dosing during cycles 2 and 3, when subjects were receiving the highest ascending dose of NGM (250 mg). Pregnancy testing, drug screening and assessment of treatment compliance were undertaken at the clinical centre at each scheduled visit after day 1 (days 28, 48, 56 and 67). During the lead-in cycle, subjects received their initial (day 1) dose at the clinical centre and thereafter continued dosing on an outpatient basis through to day 28. During cycle 2, dosing was on an outpatient basis except during days 48 50, when subjects remained at the clinical centre for assessment and 24-h pharmacokinetic sampling (pre-dose to pre-dose on days 49 50). During cycle 3, subjects received on an outpatient basis through to day 67. Subjects returned to the centre on day 67 and remained throughout the period of DCV dosing (that is, days 68 77). On days 77 78, 24-h pharmacokinetic sampling (pre-dose to pre-dose) was undertaken. Written informed consent was obtained from all patients prior to study procedures. The study was approved by the institutional review board of the study centre and was conducted in compliance with the Declaration of Helsinki, Good Clinical Practice Guidelines and local regulatory requirements. Inclusion and exclusion criteria Healthy female subjects aged 18 to 45 years with a body mass index (BMI) of kg/m 2 and intact ovarian function were eligible for enrolment into the study. Subjects had to be receiving a stable regimen of for 3 months prior to enrolment without evidence of breakthrough bleeding, or receiving a stable regimen of a different combined oral contraceptive for 3 months prior to the study and willing to switch to for 3 months during the study. Subjects were also required to have documented, acceptable Pap smear results within 1 year prior to day 1 of the study. A negative pregnancy test within 24 h prior to the start of study medication for each cycle was also required. Subjects were required to use an acceptable barrier method of contraception during the entire study through to 4 weeks after the study. Pharmacokinetic assessment Pharmacokinetic assessments were performed at steady state and pharmacokinetic evaluations were based on the concentration of study drugs in plasma at the given time points in the study. The levels of EE, NG and NGMN in human plasma were assayed using validated liquid chromatography with tandem mass spectrometry. Following a liquid liquid extraction procedure, analyte concentrations were calculated with a 1/x 2 linear regression over a concentration range of pg/ml for EE, ng/ml for NGMN and 50 25,000 pg/ml for NG and their internal standards (17a-ethynylestradiol-2,4,16,16-d4, desacetylnorgestimate-d5 and norgestrel-d5, respectively). All measurements were performed during the period of known analyte stability. Pharmacokinetic parameters were derived from plasma concentration-versus-time data and included the following:, time of maximum observed plasma concentration (T max ) and AUC in one dosing interval ( ). Plasma concentration-versustime data were analysed by non-compartmental methods using the program Kinetica (version 4.4.1; Adept Scientific, Letchworth Garden City, Herts, UK). Actual sample collection times were used for pharmacokinetic calculations. Predose concentrations and concentrations prior to the first quantifiable concentration that were below the lower limit of quantification were treated as missing for the calculation of summary statistics. The and T max were recorded directly from experimental observations; was calculated by log- and linear-trapezoidal calculations. Summary statistics for relevant pharmacokinetic parameters of each analyte were tabulated by treatment. To assess the effect of concomitant administration of DCV on EE, NGMN and NG, and mixedeffect models were fitted to log-transformed data with treatment as a fixed effect and measurements within Antiviral Therapy

4 M Bifano et al. each subject as repeated measurements. Log-scale point estimates and 90% CIs for treatment differences were subsequently exponentiated to obtain estimates on the original scale. If the 90% CIs for the geometric mean ratios (GMRs) for parameters obtained with versus without concomitant DCV were entirely contained within the conventional bioequivalence range of , then an absence of DCV effect on the pharmacokinetics of each analyte was concluded. No adjustments were made for multiplicity. All statistical analyses were carried out using SAS/STAT software (version 8.2; SAS Institute Inc., Cary, NC, USA). Safety assessments Subjects were closely monitored for AEs throughout the study. Physical examinations, vital sign measurements, 12-lead electrocardiograms (ECG) and clinical laboratory evaluations were performed at selected times throughout the study. Safety measurements were based on the results of these evaluations and on medical review of AE reports. Results Subjects A total of 20 women were enrolled and received EE/ NGM. Of these, 18 subjects completed the study. All subjects were Caucasian, with a mean age of 29.8 years (range 18 44) and a mean BMI of 24.0 kg/m 2 (range ) at screening. Pharmacokinetics of EE, NGMN and NG Mean 24 h steady-state plasma concentration time profiles for EE (Figure 2A), NGMN (Figure 2B) and NG (Figure 2C) following repeated dosing of with (day 77) and without (day 49) DCV are shown. For all analytes, peak values were reached 2 h post-dose and returned to baseline by 24 h post-dose. Individual intra-subject changes in and for dosing with and without DCV are shown for all three analytes (Figure 3). A slight increase in EE was observed in the majority of patients during coadministration of DCV (Figure 3A), but with no clear pattern observed for (Figure 3B). For NGMN and NG, a slight increase in was observed in most subjects, with no clear pattern observed for (Figure 3C 3F). Statistical comparisons of the geometric mean values for and (0 24 h post-dose) are shown for all three analytes (Table 1). In all cases, the 90% CIs for the GMRs for dosing with versus without concomitant DCV fell within the pre-specified range denoting no interaction ( ). GMR 90% CI lower boundaries for EE, NGMN and NG were 1.02, 1.06 and 1.02, respectively, indicating small increases in exposure when DCV was coadministered with EE/ NGM; however, the upper boundaries remained within the pre-defined no-effect range. Safety No serious AEs were reported. One subject discontinued study treatment as a result of back injury, which was not related to study treatments. Another subject discontinued for personal reasons. The most common AEs (those occurring in 10% of patients during any treatment period) are shown (Table 2). All AEs reported throughout the treatment periods were classified as mild in intensity. The most common AEs were headache, metrorrhagia, constipation and back pain. All subjects who experienced metrorrhagia (30% of total subjects) throughout the treatment periods had switched to from other oral contraceptives. All subjects who also experienced metrorrhagia during treatment period C (days 68 77; DCV coadministration) had experienced this AE during earlier treatment periods. No laboratory AEs were reported and no evidence of clinically meaningful effects on physical examinations, ECGs or vital sign measurements were observed. Discussion Pharmacokinetic interactions with oral contraceptives that necessitate additional or alternative methods of birth control during treatment are common among drugs with significant inhibitory or inductive effects on CYP3A4 and/or UGT. These include many HIV protease inhibitors and non-nucleoside reverse transcriptase inhibitors [24], which, unlike the finite HCV treatments, require life-long administration. Oral contraceptive failure or reductions in efficacy are frequent causes of unwanted pregnancy or breakthrough bleeding, and may result from drug drug interactions that increase EE or NGM metabolism. For example, studies of the HIV protease inhibitors atazanavir and darunavir in combination with ritonavir reduce EE exposures [25,26]. Although ritonavir is both an inhibitor of CYP3A4 and an inducer of UGT, through activation of the pregnane x receptor, the increased clearance of EE with coadministration of ritonavir suggests that clearance via UGT may be more important in the disposition of EE than CYP3A4 [27,28]. The anticonvulsant carbamazepine is also a known inducer of UGT and CYP3A4 [29]. Coadministration of carbamazepine with an EE-containing oral contraceptive results in reduced EE exposures, and increased ovulation and breakthrough bleeding, compared with that observed with administration of the oral contraceptive alone [30]. The currently approved direct-acting HCV antivirals, telaprevir and boceprevir, are significant inhibitors and International Medical Press

5 Pharmacokinetics of daclatasvir and an oral contraceptive Figure 2. Mean plasma concentration time profiles of ethinyl estradiol, norelgestromin and norgestrel A 200 on day 49 +DCV 60 mg once daily on day Concentration, pg/ml B Concentration, ng/ml C Time, h Time, h 4,000 3,500 Concentration, pg/ml 3,000 2,500 2,000 1,500 1, Time, h Mean (±sd) plasma concentration time profiles of (A) ethinyl estradiol, (B) norelgestromin and (C) norgestrel when a combined oral contraceptive is administered alone (day 49) and in combination with the NS5A replication complex inhibitor daclatasvir (DCV; 60 mg once daily, day 77) in healthy female subjects., ethinyl estradiol and norgestimate. Antiviral Therapy

6 M Bifano et al. Figure 3. and plots for ethinyl estradiol, norelgestromin and norgestrel A, pg/ml DCV Cmax, pg/ml B, pg h/ml 1,900 1,700 1,500 1,300 1, DCV 1,900 1,700 1,500 1,300 1, , pg h/ml C, ng/ml DCV Cmax, ng/ml D, ng h/ml DCV, ng h/ml E, pg/ml 5,000 4,000 3,000 2,000 1, DCV 5,000 4,000 3,000 2,000 1,000 0 Cmax, pg/ml F, pg h/ml 100,000 90,000 80,000 70,000 60,000 50,000 40,000 30,000 20,000 10, ,000 90,000 80,000 70,000 60,000 50,000 40,000 30,000 20,000 10,000 +DCV, pg h/ml Individual maximum observed plasma concentration ( ) and area under the plasma concentration time curve in one dosing interval ( ; 0 24 h post-dose) plots for (A&B) ethinyl estradiol, (C&D) norelgestromin and (E&F) norgestrel when a combined oral contraceptive is administered alone (day 49) and in combination with the NS5A replication complex inhibitor daclatasvir (DCV; 60 mg once daily; day 77) in healthy female subjects., ethinyl estradiol and norgestimate International Medical Press

7 Pharmacokinetics of daclatasvir and an oral contraceptive Table 1. Pharmacokinetic comparisons of ethinyl estradiol, norelgestromin and norgestrel for a combined oral contraceptive containing dosed with versus without concomitant DCV GMR (90% CI), with Adjusted geometric means alone (day 49) +DCV (day 77) versus without DCV Ethinyl estradiol, pg/ml (1.02, 1.20), pg h/ml (0.95, 1.07) Norelgestromin, ng/ml (0.99, 1.14), ng h/ml (1.06, 1.17) Norgestrel, pg/ml 2, , (0.99, 1.16), pg h/ml 47, , (1.02, 1.23), area under the plasma concentration time curve in one dosing interval (0 24 h post-dose);, maximum observed plasma concentration; DCV, daclatasvir;, ethinyl estradiol and norgestimate; GMR, geometric mean ratio. Table 2. Summary of adverse events occurring in 10% patients in any treatment period Treatment period A Treatment period B Treatment period C +DCV Adverse event days 1 28 a days a days a days b days b Headache 4 (20.0) 2 (10.0) 6 (30.0) 0 3 (16.7) Metrorrhagia 5 (25.0) 1 (5.0) 1 (5.0) 0 3 (16.7) Constipation (22.2) Back pain 0 1 (5.0) (16.7) Nausea (10.0) 0 1 (5.6) Irregular menstruation 2 (10.0) 0 1 (5.0) 0 0 Acne (11) 0 Abdominal pain 2 (10.0) Data are n (%). a n=20. b n=18. DCV, daclatasvir;, ethinyl estradiol and norgestimate. substrates of CYP3A4 and have been demonstrated to increase exposure to a number of CYP3A4 substrates, including the calcineurin inhibitors cyclosporine and tacrolimus, when coadministered with telaprevir [11]. By contrast, coadministration of telaprevir and an EE/ norethindrone containing contraceptive results in a 26% reduction in EE, 28% reduction in EE AUC, and 33% reduction in EE C min, which may be due to telaprevir increasing first-pass metabolism of EE in the gastrointestinal tract by affecting transporters involved in the absorption of EE [31]. Similarly, boceprevir also reduces EE AUC by 24%, while increasing the and AUC of the synthetic progestin drospirenone by 99% and 57%, respectively, substantially increasing the risk of drospirenone-related AEs [10]. The drug drug interactions observed between telaprevir and boceprevir and EE-based contraceptives necessitate the use of two nonhormonal methods of contraception during, and for telaprevir up to 2 weeks after, treatment. Ongoing clinical development of other direct-acting antivirals for HCV infection requires that their potential for drug interactions with concomitant medications is investigated. Knowledge of their oral contraceptive interactions is vital given the known teratogenic and embryocidal potential of RBV and the likelihood that these newer agents will frequently be used in PEG IFN a/ RBV-containing combinations. Few studies specifically discuss what constitutes a subtherapeutic level of EE. However, most oral contraceptives typically contain EE at a dose of µg, with low-dose contraceptives containing µg of EE. Furthermore, it is not uncommon for upward dose titration to occur in the context of low-dose EE for breakthrough bleeding. Therefore, any drug drug interactions resulting in EE levels less than those achieved with a 20 µg dose are likely to result in reduced efficacy, and potentially breakthrough bleeding [25]. In addition, it is generally accepted that even minor decreases (arbitrary definition 20% reduction in exposure; equivalent to a decrease from 30 µg to 20 µg of EE) in EE and may result in a loss of contraceptive efficacy; therefore, where this occurs, patients are advised to use non-hormonal methods of contraception to prevent pregnancy [32]. Antiviral Therapy

8 M Bifano et al. The main objective of this study was to assess the effect of the investigational NS5A replication complex inhibitor DCV on the pharmacokinetics of EE and NGMN, the primary active components of a combined oral contraceptive, in healthy female subjects. Previously, DCV has demonstrated weak time-dependent inhibition of CYP3A4 in vitro, although subsequent in vitro work identified a low potential for CYP3A4 induction based on increased CYP3A4 messenger RNA activity in human hepatocytes (Bristol Myers Squibb, unpublished data). Results from a clinical study assessing the impact of DCV on the pharmacokinetics of the CYP3A4 substrate midazolam demonstrated that DCV is unlikely to have a clinically significant impact on exposures to CYP3A4 substrates (Bristol Myers Squibb, unpublished data). The potential for an interaction between DCV and substrates of sulfotransferase or UGTs has not been investigated. Unlike the reductions in EE exposure observed with concomitant telaprevir and boceprevir, in the current study only small increases (6 11% increase in GMR) in the of EE, NGMN and NG were observed with combined dosing of and DCV, and, similarly, modest increases (approximately 12%) in the of NGMN and NG. All comparisons fell within the prespecified range for no effect (90% CIs for GMRs contained within the conventional bioequivalence range of ), indicating that DCV does not have any clinically relevant effects on any active component of. In addition, coadministration of DCV with did not increase the frequency of metrorrhagia observed or change the individuals affected during cycle 3 compared with the administration of alone (cycles 1 and 2), suggesting maintenance of contraceptive efficacy of during DCV coadministration. Administration of DCV in combination with a combined oral contraceptive was also well tolerated in this study, with no serious or life-threatening AEs or AE-related discontinuations. Most AEs recorded were mild in intensity and were comparable to those observed during DCV monotherapy in HCV-infected patients [33]. Assessing the effect of anti-hcv drugs on the efficacy on oral contraceptives is a challenging undertaking. Most drug drug interaction studies investigate only two drugs at a time to enable interpretation of any changes in pharmacokinetic parameters. However, assessing the effect of anti-hcv drugs, including DCV, individually does not reflect their real-world application as part of combination treatment regimens, when there may be multiple layers of enzyme induction or inhibition as well as other physiologic effects that may alter drug absorption or excretion. Indeed, future assessments looking at combination DAAs and oral contraceptive drug drug interactions may be warranted to reflect the clinical use of these new agents. There are also disadvantages to conducting this, and other pharmacokinetic studies, in healthy HCV-negative subjects, who typically have lower BMIs and normal liver function compared with HCV-infected patients, which may have implications for drug metabolism and drug drug interactions. In addition, most drug drug interaction studies, including the current study, investigate only one type of oral contraceptive. Although the results from the current study suggest that DCV is unlikely to have any clinically meaningful effects on other EE-based oral contraceptives, it cannot be fully ascertained from the results presented herein that DCV will not have any effects on any other oral contraceptives that are currently available. In conclusion, the results of this study indicate that coadministration of DCV and an oral contraceptive containing EE and a progestin is well tolerated, does not result in clinically significant changes in exposure to either component, and hence, a loss of contraceptive efficacy due to a pharmacokinetic interaction is unlikely. Acknowledgements Editorial assistance was provided by Kate Gaffey of Articulate Science (Manchester, UK) and was funded by Bristol Myers Squibb. All authors wrote the manuscript. MB, DG and RB designed the research. MB, HS and CH analysed the data. HK and HJ contributed new reagents/ analytical tools. Disclosure statement All authors are employees of Bristol Myers Squibb. References 1. Negro F, Alberti A. The global health burden of hepatitis C virus infection. Liver Int 2011; 31: Armstrong GL, Wasley A, Simard EP, McQuillan GM, Kuhnert WL, Alter MJ. 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