Virologic Response Following Combined Ledipasvir and Sofosbuvir Administration in Patients With HCV Genotype 1 and HIV Co-infection

Abstract

IMPORTANCE

There is an unmet need for interferon- and ribavirin-free treatment for chronic hepatitis C virus (HCV) infection in patients co-infected with human immunodeficiency virus (HIV).

OBJECTIVE

To evaluate the rates of sustained virologic response (SVR) and adverse events in previously untreated patients with HCV genotype 1 and HIV co-infection following a 12-week treatment of the fixed-dose combination of ledipasvir and sofosbuvir.

DESIGN, SETTING, AND PARTICIPANTS

Open-label, single-center, phase 2b pilot study of previously untreated, noncirrhotic patients with HCV genotype 1 and HIV co-infection conducted at the Clinical Research Center of the National Institutes of Health, Bethesda, Maryland, from June 2013 to September 2014. Patients included those receiving antiretroviral therapy with HIV RNA values of 50 copies/mL or fewer and a CD4 T-lymphocyte count of 100 cells/mL or greater or patients with untreated HIV infection with a CD4 T-lymphocyte count of 500 cells/mL or greater. Serial measurements of safety parameters, virologic and host immune correlates, and adherence were performed.

INTERVENTIONS

Fifty patients with HCV genotype 1 never before treated for HCV were prescribed a fixed-dose combination of ledipasvir (90 mg) and sofosbuvir (400 mg) once daily for 12 weeks.

MAIN OUTCOMES AND MEASURES

The primary study outcome was the proportion of patients with sustained viral response (plasma HCV RNA level <12 IU/mL) 12 weeks after end of treatment.

RESULTS

Forty-nine of 50 participants (98% [95% CI, 89% to 100%]) achieved SVR 12 weeks after end of treatment, whereas 1 patient experienced relapse at week 4 following treatment. In the patient with relapse, deep sequencing revealed a resistance associated mutation in the NS5A region conferring resistance to NS5A inhibitors, such as ledipasvir. The most common adverse events were nasal congestion (16% of patients) and myalgia (14%). There were no discontinuations or serious adverse events attributable to study drug.

CONCLUSIONS AND RELEVANCE

In this open-label, uncontrolled, pilot study enrolling patients co-infected with HCV genotype 1 and HIV, administration of an oral combination of ledipasvir and sofosbuvir for 12 weeks was associated with high rates of SVR after treatment completion. Larger studies that also include patients with cirrhosis and lower CD4 T-cell counts are required to understand if the results of this study generalize to all patients co-infected with HCV and HIV.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01878799

Approximately 185 million people are infected with chronic hepatitis C (HCV) infection worldwide, and about 5 million are co-infected with human immunodeficiency (HIV).¹ In the United States, co-infection occurs in approximately one-third of all patients with HIV-1 infection, with incidence rates as high as 75% to 90% among patients with reported history of intravenous drug use, and is associated with higher rates of end-stage liver disease, liver cancer, and mortality.^2,3

Prior to 2013, treatment of HCV genotype-1 infection in individuals with HIV co-infection required 24 to 48 weeks of pegylated interferon, ribavirin, and a protease inhibitor (either boceprevir or telaprevir).⁴ Although this regimen was associated with improved rates of sustained virologic response (SVR) when compared with those observed with pegylated interferon and ribavirin alone,^5–7 widespread use was limited because of high rates of adverse events, discontinuation rates, and complex drug-drug interactions.^4,8,9

In 2013, 2 new directly acting antiviral agents—sofosbuvir, an HCV NS5B polymerase inhibitor, and simeprevir, an NS3/4A protease inhibitor—were licensed for treatment of HCV.^10,11 Although sofosbuvir and ribavirin for 24 weeks was associated with high rates of SVR in HIV-negative and HIV-positive patients with HCV genotype 1,^12,13 modest rates of hemoglobin decline were attributable to concomitant use of ribavirin. Recent studies evaluating the combination of ledipasvir, an HCV NS5A inhibitor, along with sofosbuvir, in a fixed-dose combination with or without ribavirin for 8 to 24 weeks, have demonstrated SVR rates of 91% to 100% in patients monoinfected with HCV genotype 1 who either have or have not previously received HCV treatment.^5–7,14,15 In this study, we evaluated the rates of SVR following a 12-week treatment regimen of a fixed-dose combination of ledipasvir and sofosbuvir in patients co-infected with HCV genotype 1 and HIV who were not previously treated for HCV.

Methods

Participants

Participants were enrolled in a single-center, open-label, uncontrolled, nonrandomized phase 2b trial conducted at the Clinical Research Center of the National Institutes of Health (NIH), Bethesda, Maryland, from June 2013 to September 2014. Patients were recruited from existing HCV clinics in the District of Columbia as previously described.¹³ Patients were contacted for screening based on the order of initial communication with the study team and for start of study drugs based on completion of eligibility requirements. The study protocol is available in Supplement 1.

Eligible participants were at least 18 years old, had not received prior HCV treatment, and were co-infected with HCV genotype 1 and HIV. Participants could either not be receiving antiretroviral therapy with a CD4 T-lymphocyte count of 500 cells/mm³ or greater regardless of HIV viral load, a stable CD4 count with HIV viral load less than 500 copies/mL, or could be receiving a protocol-approved antiretroviral regimen with HIV RNA values of 50 copies/mL or fewer with a CD4 T-lymphocyte count of 100 cells/μL or greater. Participants receiving antiretroviral drugs were required to have been receiving a stable treatment-regimen for at least 8 weeks prior to starting study drug. Acceptable antiretroviral drugs were emtricitabine plus tenofovir and/or efavirenz, raltegravir, or rilpivirine.

Participants with cirrhosis, who may be less responsive to HCV treatment, were excluded from this investigational study. The presence or absence of cirrhosis was determined by liver biopsy within the previous 3 years of enrollment or by a combination of FibroSURE (Laboratory Corporation of America) score less than 0.48 and aspartate aminotransferase/platelet ratio index less than 1. A FibroSURE score less than 0.48 corresponds with a fibrosis stage from 0 to 2.

Race and ethnicity were self-reported. All eligible participants were required to have a primary medical provider and, if opioid-dependent, needed to be participating in supervised treatment. Full eligibility criteria are included in eAppendix 1 in Supplement 2.

Study Oversight

The study was approved by the National Institute of Allergy and Infectious Diseases (NIAID) institutional review board and was conducted in compliance with the Good Clinical Practice guidelines, the Declaration of Helsinki, and regulatory requirements. Written or oral informed consent approved by the NIAID institutional review board was obtained from all participants. The Regulatory Compliance and Human Participants Protection Branch of NIAID served as the study sponsor and medical monitor. Data collection, review and analysis, and writing were performed by NIH and Institute of Human Virology investigators.

Study Design

Participants from outpatient community clinics were prescribed a combination tablet containing ledipasvir (90 mg) and sofosbuvir (400 mg), administered orally for 12 weeks. Patients received instructions for proper administration of study drug. Criteria for stopping study medications were based on specific safety or virologic measures. Participants would be discontinued from therapy if they did not achieve a greater than 2 log₁₀ decrease in HCV RNA values (unless a >2 log₁₀ decrease would be below the lower limit of quantification [LLOQ] at their week 4 visit or if their serum RNA level was greater than or equal to the LLOQ at their week 8 visit [eAppendix 2 in Supplement 2]). Participants who did not achieve SVR 12 weeks after treatment completion (SVR₁₂) were offered the option of additional treatment with the current standard of care. In addition to their screening visit, patients were reminded to return to the NIH for outpatient visits at days 0, 1, 3, 5, 7, and 10 and weeks 2, 3, 4, 8, 12, 14, 16, 20, and 24, which corresponds to an SVR₁₂ visit.

Outcome Measures

Plasma HCV RNA levels were measured using the real-time HCV assay (Abbott), with an LLOQ of 12 IU/mL. The assay was used to measure HCV RNA levels in all participants at all time points. Serum HCV RNA levels were also measured using the COBAS TaqMan HCV RNA assay version 2.0 (Roche), with an LLOQ of 43 IU/mL at screening, week 4, week 8, end of treatment, 4 weeks after treatment, and 12 weeks after treatment. Plasma HIV RNA levels were measured at all points using reverse transcription polymerase chain reaction (real-time HIV assay), with an LLOQ of 40 copies/mL.

Hepatitis C viral relapse was defined as an HCV RNA level higher than the LLOQ at any posttreatment point after having an HCV RNA level lower than the LLOQ at the end of treatment. Hepatitis C viral breakthrough was defined as an HCV RNA level at the LLOQ or higher during treatment after having previously had an HCV RNA level lower than the LLOQ while taking study drugs, confirmed with 2 consecutive values. Renal function was assessed using both creatinine levels and estimated glomerular filtration rate (eGFR, calculated using the CKD-EPI equation).¹⁶

Safety and Adherence

Adverse events and clinical laboratory results were recorded throughout the study. Adverse events were graded from 1 (mild) to 4 (severe) according to the NIAID Division of AIDS toxicity table (version 1.0).¹⁷ Patient adherence was determined by pill counts at weeks 1, 4, 8, and end of treatment. Patients were determined to be fully adherent to the regimen if they missed no doses over the course of treatment.

Viral Kinetics

During the first 28 days of treatment, HCV RNA levels were measured at day 0, 1, 3, 5, 7, 10, 14, 21, and 28 in all patients. In 20 patients (10 not receiving antiretroviral treatment and 10 receiving antiretroviral treatment), HCV RNA levels were also obtained at 0, 1, 2, 4, 8, 12, 24, and 36 hours after administration of first dose of study.

IL28B and IFNL4 Genotyping

IL28B and IFNL4 single-nucleotide polymorphisms have previously been described as determinants of SVR.^18,19 IL28B and IFNL4 genotype was determined on DNA specimens using 5' nuclease assay with IL28B and IFNL4 allele-specific TaqMan probes (ABI TaqMan allelic discrimination kit) and the ABI7500 Real-Time PCR system (Applied Biosystems). Genotyping of variants at the rs12979860 (referred to as IL28B genotype) and rs368234815 (IFNL4) loci was performed as previously described.¹⁸

Liver Biopsy

An optional additional liver biopsy was offered after treatment completion to participants who had an initial liver biopsy performed at the NIH Clinical Center. Assessments were performed by a single pathologist and staged according to the Knodell Histological Activity Index.²⁰

Clinical End Points

The primary end point was sustained virologic response (HCV RNA level <12 IU/mL by real-time HIV assay) at 12 weeks after treatment completion (SVR₁₂) among all patients enrolled in the study. Safety end points included frequency and severity of adverse events, discontinuations attributable to adverse events, and safety laboratory changes.

Secondary end points that have been completed and included here are the proportion of participants with unquantifiable HCV viral load at specified points during and after treatment, discontinuations attributable to adverse events, safety laboratory changes, and evaluation of HCV resistance mutations in the patient who experienced relapse. Data through SVR₁₂ are included here.

Modeling Viral Kinetics

Viral kinetic modeling with a multiscale model was performed for all participants as previously described.^21,22 A detailed version of the methodology is described in eAppendix 3 in Supplement 2.

Deep Sequencing

Deep sequencing of the HCV NS5A and NS5B regions was performed only for the patient who experienced relapse, from samples collected at baseline and at the time of virologic failure, using DDL (DDL Diagnostics Laboratory). The NS3, NS5A, and NS5B were amplified by RT-PCR using HCV genotype-specific primers. The PCR products were sequenced by Illumina MiSeq technology as described elsewhere.²³ Deep sequencing that covers 5000 reads was performed for each sample.

Statistical Analysis

The primary virologic response and safety analyses were based on an intention-to-treat population (all patients who received at least 1 dose of study medication). In terms of safety, a sample size of 50 was calculated as sufficient to have a 96% chance of observing at least 1 adverse event having a probability of 10% or greater. With 50 participants, the study would be able to estimate the proportion of patients with suppression to below the limit of detection to within plus or minus 0.11, based on a 95% confidence interval.

Baseline demographics were compared using the Wilcoxon rank-sum test for continuous outcomes and χ² tests for binary outcomes. Estimated decline in HCV viral load at different times was compared using a Wilcoxon rank-sum test. Analyses were performed using BiAS, PRISM 6.0 (GraphPad), SAS (SAS Institute Inc), STAT-CRUNCH, and S-Plus 8.0.

Results

Baseline Characteristics

Sixty-three potential participants were screened and 50 were enrolled (eFigure 1 in Supplement 2). Six participants screened and declined to participate, and 7 participants did not meet inclusion criteria (see eTable 1 in Supplement 2 for reasons for exclusion). Of the 50 enrolled, 37 were receiving antiretroviral treatment and 13 were not receiving antiretroviral treatment.

The demographic and baseline clinical characteristics are shown in Table 1. Median baseline CD4 count was 576 (95% CI, 453–657) cells/mm³ for patients receiving antiretroviral treatment and 687 (95% CI, 518–960) cells/mm³ for patients not receiving antiretroviral treatment. Participants were predominantly African American (84%), men (74%), IL28B non-CC genotype (84%), with genotype 1a infection (74%). Thirteen of 50 patients (26%) had stage 3 liver disease.

Table 1.

Baseline Demographics and Clinical Characteristics of Study Participants

	Antiretroviral Therapy
Characteristic	No (n = 13)	Yes (n = 37)
Age, median (IQR), y	59 (54–62)	58 (51–63)
Men, No. (%)	7(54)	30 (81)
Body mass index, median (IQR)a	26 (23–29)	26 (22–29)
BMI ≥30, No. (%)	3 (23)	8 (22)
Race/ethnicity, No. (%)b
White	3(13)	4 (11)
Black	10 (77)	32 (86)
Hispanic	0	1 (3)
Fibrosis score, No. (%)c
0	2(15)	8 (22)
1	6 (46)	19(51)
2	0	2 (5)
3	5(38)	8 (22)
HCV genotype 1 subtype, No. (%)
1A	9 (75)	30 (81)
1B	3 (25)	7 (19)
IL28B genotype, No. (%)
CC	2 (15)	6 (16)
CT	6 (46)	18 (39)
TT	5 (38)	13 (35)
IFNL4 genotype, No. (%)
TT/TT	2 (15)	6 (16)
ΔG/TT	6 (46)	15 (41)
ΔG/ΔG	5 (38)	16 (43)
Baseline HCV RNA,-log10IU/mL
Median (IQR)	6.1 (5.3–6.5)	6.0 (5.4–6.5)
Mean	5.8	6.0
HCV RNA >6 million IU/mL, No. (%)	5 (50)	14 (38)
Baseline creatinine, median (range), mg/dLd	0.79 (0.69–0.98)	0.91 (0.82–1.10)
Baseline eGFR, median (range), mL/min	101 (94–115)	93 (83–112)
CD4, cells/mm3, No. (%)
<200	0	1(3)
200–350	1 (8)	8 (22)
>350	12 (92)	28 (76)
Antiretroviral use
Tenofovir/emtricitabine plus	0	37 (100)
Efavirenz		15 (41)
Raltegravir		10 (27)
Rilpivirine		8(21)
Raltegravir/rilpivirine		3 (8)
Raltegravir/efavirenz		1 (3)

Abbreviations: BMI, body mass index; eGFR, estimated glomerular filtration rate; HCV, hepatitis C virus; IQR, interquartile range.

SI conversion factor: To convert creatinine values to μmol/L, multiply by 88.4.

^aCalculated as weight in kilograms divided by height in meters squared.

^bSelf-reported.

^cFibrosis determined either by Knodell Histological Activity Index score (a low score ranges from 0–2; a high score from 3 to 4) or by FibroSURE test. Forty-four patients were classified based on liver biopsy. Six patients were classified based on FibroSURE score.

^dBaseline creatinine level (mg/dL) was the only significant difference in baseline characteristics between patients not receiving and receiving antiretroviral treatment (P = .01).

Virologic Response During and After Treatment

All 50 participants achieved virologic suppression lower than the LLOQ by week 4 of therapy (Table 2; eTable 2 in Supplement 2). All 13 participants not receiving antiretroviral treatment achieved SVR₁₂ (100% [95% CI, 75%-100%]). Of the 37 participants receiving antiretroviral treatment, 36 (97% [95% CI, 89%-100%]) achieved SVR₁₂.

Table 2.

Patients With HCV RNA Levels Below the Level of Quantification at Various Times of Treatment and Follow-up^a

	Antiretroviral Therapy, No. (%) [95% CI]b
Week	No (n = 13)	Yes (n = 37)
Treatment Period
4	13 (100) [75–100]	37 (100) [91–100]
8	13 (100) [75–100]	37 (100) [91–100]
12	13 (100) [75–100]	37 (100) [91–100]
Postttreatment Period
2	13 (100) [75–100]	37 (100) [91–100]
4	13 (100) [75–100]	36 (97) [89–100]
8	13 (100) [75–100]	36 (97) [89–100]
12 (SVR12)	13 (100) [75–100]	36 (97) [89–100]

Abbreviation: SVR, sustained viral response.

^aTreatment response in all participants was included in the intention-to-treat analysis in all 50 participants. The RNA assay was used for these points, with a lower limit of quantification of 43 IU/mL.

^bThe CI for proportion estimate for each treatment is obtained using the binomial distribution

Changes in Liver Function

Levels of alanine aminotransferase and aspartate aminotransferase normalized rapidly with treatment (eFigure 2 in Supplement 2). A comparison of pretreatment and posttreatment paired liver biopsies showed Knodell Histological Activity Index inflammation improved by a mean of 2.2 (from 8.07 to 5.86) with treatment (P = .01) (eFigure 3 in Supplement 2).

One patient did not achieve SVR₁₂ and experienced relapse by week 4 after treatment completion. This was a 63-year-old African American woman, IL28B genotype TT, with HCV genotype 1b infection, a baseline HCV viral load of 5 338 580 IU/mL by real-time HIV assay, and stage 1 liver disease. She was receiving tenofovir plus emtricitabine and rilpivirine for HIV infection with viral suppression. She achieved viral suppression lower than the LLOQ by week 4, which was maintained through 12 weeks. At week 4 after treatment completion, HCV viral load was 64 749IU/mL by real-time HIV assay. This patient has been lost to follow-up.

Viral Resistance Testing

Deep sequencing was carried out for the 1 participant who experienced relapse. The only mutation was seen in the NS5A region. The participant had 58% of Y93H mutation at baseline, which was enriched to 89% at day 3 and to greater than 99% at relapse. This mutation confers resistance to NS5A inhibitors, such as ledipasvir in vitro.

HCV Viral Kinetic Response

Viral kinetic modeling showed a rapid, sustained decline in HCV RNA in both groups (Figure). This multistage model was fitted in each participant shown in eFigure 4 in Supplement 2. Median overall treatment effect (ε) observed in participants receiving and not receiving antiretroviral treatment was similar (treated, 99.98%; not treated, 99.98%; P = .78). Clearance rate (c) of free virions (9.05 vs 10.3, P = .68) and loss of infected hepatocytes (δ) (0.13 vs 0.17, P = .25) were not significantly different between patients in the 2 groups. The virologic response rates were similar in patients receiving and not receiving antiretroviral treatment at the time of treatment.

Figure. Decline in Median HCV Viral Load After Initiation of Study Drugs, Days 0–28.

Baseline log hepatitis C virus (HCV) viral load was similar in both groups (6.0 [SD, 0.1] IU/mL in patients receiving antiretroviral (ARV) treatment and 6.1 in patients not receiving ARV treatment [SD, 0.3] in [P = .49]). The study drug combination of ledipasvir and sofosbuvir was equally effective in patients not receiving and receiving ARV treatment (P = .78 for total effectiveness). Lower limit of quantification is 12 IU/mL.

Adverse Events

There were no deaths or discontinuations observed in this study. Most adverse events were grade 1 in severity, with the most common being nasal congestion, myalgia, headache, and fatigue (Table 3). There were 4 grade 3 events, namely, decreased absolute neutrophil count, pneumonia, elevated aspartate aminotransferase level, and right upper quadrant pain. There was 1 grade 4 event (abnormal creatine phosphokinase level) in a participant who reported initiation of a vigorous exercise program, which resolved while the patient was still receiving study drugs. There was 1 significant adverse event reported in a smoker with a history of chronic bronchitis who was hospitalized with pneumonia in the winter. Symptoms resolved while the patient was receiving study drug, and the adverse event was determined to be unlikely related to the study drug.

Table 3.

Treatment Discontinuations, Adverse Events, and Hematologic Abnormalities

	Antiretroviral Therapy, No. (%)
Variable	No (n = 13)	Yes (n = 37)	Overall (n = 50)
Treatment discontinuation	0	0	0
Any adverse event	13 (100)	37 (100)	50 (100)
Common adverse event
Nasal congestion	2(15)	6(16)	8(16)
Myalgia	5(38)	2 (5)	7(14)
Headache	1(8)	4(11)	5 (10)
Fatigue	3 (23)	2 (5)	5 (10)
Diarrhea	2 (15)	2 (5)	4 (8)
Nausea	1 (8)	2 (5)	3 (6)
Constipation	2 (15)	1 (3)	3 (6)
Urinarytract infection	1 (8)	2 (5)	3 (6)
Serious adverse event
Pneumonia	1 (8)	0	1 (2)
Hematologic abnormalitya
Increased aspartate aminotransferase (201–400 U/L)	0	1 (3)	1 (2)
Increased blood creatinine phosphokinase (≥6130 U/L)	0	1 (3)	1 (2)
Decreased neutrophilcount (0.500–0.749 K/uL)	1 (8)	0	1 (2)
Elevated lipase (181–300 U/L)	0	1 (3)	1 (2)

^aPercentage represents proportion of patients who had at least 1 laboratory value above the upper limit of normal.

Changes in Renal Function

At baseline, median serum creatinine levels were significantly different between patients not receiving antiretroviral treatment (0.81 mg/dL [to convert to μmol/L, multiply by 88.4]) and those receiving treatment (0.91 mg/dL) (P = .01). There were no significant changes in estimated serum creatinine levels or eGFRs over time (Table 4, eFigure 5 in Supplement 2). No participants were identified as having a treatment-emergent eGFR less than 50 mL/min or a decrease in eGFR (mL/min) greater than 25%.

Table 4.

Changes in Renal Parameters Over Time

	Antiretroviral Therapy, Median (95% CI)
Change at Week	No (n = 13)	Yes (n = 37)	P Value
eGFR, mL/mina
4	−1.0 (−9.0 to 6.0)	−2.0 (−5.0 to 0)	.46
8	−3.0 (−8.0 to 2.0)	−1.0 (−7.0 to 1.0)	.86
12	0.0 (−11.0 to 1.0)	−4.0 (−6.0 to 1.0)	.92
Creatinine, mg/dL
4	0.01 (−0.08 to 0.11)	0.02 (−0.01 to 0.08)	.51
8	0.04 (−0.04 to 0.11)	0.02 (−0.01 to 0.11)	.98
12	0.06 (−0.02 to 0.16)	0.03 (−0.05 to 0.08)	.26
	No Efavirenz (n = 21)	Efavirenz (n = 16)
eGFR, mL/mina
4	−1.0 (−10.0 to 2.0)	−5.0 (−7.0 to 1.0)	.66
8	0.0 (−3.0 to 4.0)	−6.5 (−13.0 to 2.0)	.22
12	−4.0 (−12.0 to 3.0)	−4.0 (−8.0 to 3.0)	.76
Creatinine, mg/dL
4	0.01 (−0.06 to 0.10)	0.05 (−0.01 to 0.10)	.51
8	0.0 (−0.04 to 0.03)	0.09 (−0.03 to 0.13)	.14
12	0.01 (−0.06 to 0.08)	0.04 (−0.09 to 0.17)	.53

Abbreviation: eGFR, estimated glomerular filtration rate.

SI conversion factor: To convert creatinine values to μmol/L, multiply by 88.4.

^aNo patients were identified as having a treatment-emergent eGFR less than 50 mL/min or a decrease in eGFR greater than 25% mL/min.

One patient developed treatment-emergent hypophosphatemia (serum phosphorus level, 2.5 mg/dL [0.81 mmol/L]; grade 1) associated with a transient elevation in serum creatinine level, which resolved with treatment. This patient was receiving rilpivirine/tenofovir/emtricitabine and raltegravir. Two additional patients developed normoglycemic glycosuria that resolved with treatment.

Changes in HIV Parameters

Eight participants receiving antiretroviral treatment who experienced an increase in HIV viral load (HIV-1 RNA ≥40 copies/ mL, <1 log increase from nadir [eTable 3 in Supplement 2]) while in the study. All 8 participants achieved SVR₁₂. One participant had a greater than 1 log increase in HIV viral load. This participant had missed 5 days of antiretrovirals (rilpivirine/ tenofovir/emtricitabine + raltegravir) and had an HIV viral load of 594 copies/mL at week 4. He continued the same regimen. By the next visit (week 8), his HIV viral load was less than 20 copies/mL and he also achieved SVR₁₂. Participants not receiving antiretroviral treatment who had HIV RNA levels greater than 50 copies/mL at baseline did not experience any significant increases in their HIV viral load over the course of therapy (eTable 4 in Supplement 2). There were no significant changes in CD4 cell counts or CD4 cell percentages with treatment for participants both receiving and not receiving antiretroviral treatment (eTable 5 in Supplement 2).

Adherence

Adherence to ledipasvir and sofosbuvir, as measured by pill counts, was high over the course of treatment. Fifty percent of all participants had no missed doses (54% among participants not receiving antiretroviral treatment; 49% among participants receiving antiretroviral treatment). Forty percent of patients missed 1 to 4 doses of study drug, for an adherence rate greater than 95%. Five patients missed 5 or more doses of study drug over the course of treatment. As determined by pill count at the end of study, the participant who experienced HCV viral relapse by week 4 after treatment completion reported no missed doses.

Discussion

In this open-label, uncontrolled, nonrandomized trial, the combination of ledipasvir and sofosbuvir was associated with high rates of SVR in participants co-infected with HCV genotype 1 and HIV, similar to that observed inpatients monoinfected with HCV genotype 1.¹⁴ These results show for the first time, to our knowledge, that an interferon- and ribavirin-free therapy is associated with high SVR rates in patients co-infected with HCV and HIV.

Traditionally, interferon-based therapies have resulted in lower rates of SVR among patients co-infected with HCV and HIV as compared with patients monoinfected with HCV.^5,6 However, recent studies have shown that the addition of directly acting antiviral agents (telaprevir, boceprevir, simeprevir, and sofosbuvir) has increased SVR in patients co-infected with HCV and HIV, reporting similar rates of SVR that were observed with patients monoinfected with HCV.^4,8,24,25 Yet many of these studies used interferon, ribavirin, or both concomitantly with an exacerbation of adverse events in HIV-positive patients.^4,8,24,25 Most recently, the once-daily, single-tablet regimen of ledipasvir and sofosbuvir, with or without ribavirin, has been shown to be an effective regimen to treat hepatitis C in HIV-negative individuals.^14,15,26

The participants included in this study had many previously described poor prognostic factors, namely, African American race (84%), male sex (74%), IL28B non-CC genotype (84%), and genotype 1a infection (74%). We have hypothesized that many of these factors may no longer be relevant in determining responses to HCV treatment. All 13 patients not receiving antiretroviral treatment and 36 of 37 patients receiving antiretroviral treatment achieved SVR, regardless of HIV viral suppression. In the 1 participant who experienced relapse, HCV sequencing data showed that the Y93H mutation in the NS5A region was detected at baseline and was enriched during the study and at the time of relapse.

In this study, most adverse events associated with combined ledipasvir and sofosbuvir by participants co-infected with HCV and HIV were mild (grade 1–2) and clinically managed. There were no deaths, medication discontinuations, severe adverse events, or grade 4 adverse events attributable to the study drug. Given the potential drug interaction between ledipasvir and tenofovir resulting in increases in tenofovir levels, we performed additional safety evaluation in participants receiving antiretroviral treatment. Although there were no significant changes in eGFRs and serum creatinine levels throughout this study, larger studies are required to definitively determine the potential for renal toxicity.

Other studies have demonstrated that drug-drug interactions between certain directly acting antiviral agents such as boceprevir, telaprevir, and antiretrovirals could result in adverse events or antiretroviral failures, restricting the wider use of these directly acting antiviral agents in patients with HIV. We found no significant change in HIV viral load levels, CD4 T cells, or occurrence of opportunistic infections. The HIV viral breakthrough documented in 1 participant was associated with nonadherence to antiretroviral treatment.

Although only 10% of participants missed 5 or more doses of medications, adherence monitoring should remain a key aspect of treatment in the real world.

Study limitations include the lack of a control group and exclusion of participants with cirrhosis. In addition, use of antiretroviral therapy was limited to those for whom interactions with ledipasvir were predicted to be not clinically relevant. In particular, HIV protease inhibitors and nonnucleoside reverse transcriptase inhibitors are widely used in clinical practice; other than efavirenz or rilpivirine, these agents were not permitted in this study. Although participants with lower CD4 T-cell counts (>100 cells/mL for patients receiving antiretroviral therapy) were permitted, few of these participants enrolled (median baseline CD4 of participants receiving antiretroviral therapy was 576 cells/mL). Several large, ongoing studies of combined ledipasvir and sofosbuvir use among patients coinfected with HCV and HIV will help address some of these questions.

Conclusions

In this open-label, uncontrolled, pilot study enrolling patients co-infected with HCV genotype 1 and HIV, administration of an oral combination of ledipasvir and sofosbuvir for 12 weeks was associated with high rates of SVR after treatment completion. Larger studies that also include patients with cirrhosis and lower CD4 T-cell counts are required to understand if the results of this study generalize to all patients infected with HCV and HIV.