Response-guided telaprevir therapy in prior relapsers? The role of bridging data from treatment-naïve and experienced subjects

Modeling population heterogeneity in viral dynamics for chronic hepatitis C infection: Insights from Phase 3 telaprevir clinical studies

Viral dynamic modelling has proven useful for designing clinical studies and predicting treatment outcomes for patients infected with the hepatitis C virus. Generally these models aim to capture and predict the on-treatment viral load dynamics from a small study of individual patients. Here, we explored extending these models (1) to clinical studies with numerous patients and (2) by incorporating additional data types, including sequence data and prior response to interferon. Data from Phase 3 clinical studies of the direct-acting antiviral telaprevir (T; total daily dose of 2250 mg) combined with pegylated-interferon alfa and ribavirin (PR) were used for the analysis. The following data in the treatment-naïve population were reserved to verify the model: (1) a T/PR regimen where T was dosed every 8 h for 8 weeks (T8(q8h)/PR) and (2) a T/PR regimen where T was dosed twice daily for 12 weeks (T12(b.i.d.)/PR). The resulting model accurately predicted (1) sustained virologic response rates for both of these dosing regimens and (2) viral breakthrough characteristics of the T8(q8h)/PR regimen. Since the observed viral variants depend on the T exposure, the second verification suggested that the model was correctly sensitive to the different T regimen even though the model was developed using data from another T regimen. Furthermore, the model predicted that b.i.d. T dosing was comparable to q8h T dosing in the PR-experienced population, a comparison that has not been made in a controlled clinical study. The methods developed in this work to estimate the variability occurring below the limit of detection for the viral load were critical for making accurate predictions.

Virological outcomes and treatment algorithms utilisation in observational study of patients with chronic hepatitis C treated with boceprevir or telaprevir

BACKGROUND

HCV-TARGET is a longitudinal observational study of chronic hepatitis C virus (HCV) patients treated with direct-acting anti-viral agents (DAAs) in a US consortium of 90 academic and community medical centres.

AIM

To assess utilisation of response-guided therapy (RGT) and sustained virological response (SVR) of a large cohort of patients.

METHODS

Patients received peginterferon (PEG-IFN), ribavirin and either telaprevir or boceprevir. Demographical, clinical and virological data were collected during treatment and follow-up. RGT and treatment futility stopping rules was assessed at key time points.

RESULTS

Of 2084 patients, 38% had cirrhosis and 56% had received prior treatment for HCV. SVR rates were 31% (95% CI: 24-40) and 50% (95% CI: 44-56) in boceprevir patients with and without cirrhosis, respectively. SVR rates were 46% (95% CI: 42-50) and 60% (95% CI: 57-64) in telaprevir patients with and without cirrhosis, respectively. Early clearance of virus, IL28B genotype, platelet counts and diabetes were identified as predictors of SVR among boceprevir patients, while early clearance of virus, IL28B, cirrhosis, HCV subtype, age, haemoglobin, bilirubin and albumin levels were identified as predictors of SVR for telaprevir patients.

CONCLUSIONS

In academic and community centres, triple therapy including boceprevir or telaprevir led to SVR rates somewhat lower than those noted in large phase 3 clinical trials. Response rates were consistently higher among patients without cirrhosis compared to those with cirrhosis regardless of DAA used and prior treatment response. Trial registration clinicaltrials.gov NCT01474811.

Emerging treatments for chronic hepatitis C

Advances in understanding the hepatitis C virus (HCV) life cycle and the urgent need to find complementary direct-acting antiviral (DAA) therapies has led to substantial advancements in treating chronic hepatitis C. The introduction of telaprevir and boceprevir in 2011 increased the sustained virological response (SVR) rate from approximately 50% to > 70%, but this therapy further restricted patient eligibility and is only approved for treating HCV genotype 1 infection. Interferon has long remained the backbone of HCV therapy and helps prevent viral breakthrough. However, interferon has limited effectiveness and is associated with severe adverse effects and toxicity, especially among cirrhotic patients. Moving to interferon-free therapies should greatly improve SVR rates and offer new treatments for other HCV genotypes and for ineligible patients or patients failing to respond to prior therapies. However, without the relative safety of interferon to suppress viral escape, vigilance will be required to select appropriate therapies and monitor resistance. Several DAAs are currently undergoing clinical trials and will soon undergo the approval process. Goals of future HCV clinical research will be to identify combinations of DAAs with high genetic barriers, investigate optimal treatment doses and durations, and determine the role of ribavirin in DAA therapies.

Telaprevir- and boceprevir-based tritherapies in real practice for F3-F4 pretreated hepatitis C virus patients

AIM: To assess, in a routine practice setting, the sustained virologic response (SVR) to telaprevir (TPV) or boceprevir (BOC) in hepatitis C virus (HCV) null-responders or relapsers with severe liver fibrosis.

METHODS: One hundred twenty-five patients were treated prospectively for 48 wk with TPV or BOC + pegylated-interferon (peg-INF) α2a + ribavirin (PR) according to standard treatment schedules without randomization. These patients were treated in routine practice settings in 10 public or private health care centers, and the data were prospectively collected. Only patients with severe liver fibrosis (Metavir scores of F3 or F4 upon liver biopsy or liver stiffness assessed by elastography), genotype 1 HCV and who were null-responders or relapsers to prior PR combination therapy were included in this study.

RESULTS: The Metavir fibrosis scores were F3 in 35 (28%) and F4 in 90 (72%) of the patients. In total, 62.9% of the patients were null-responders and 37.1% relapsers to the previous PR therapy. The overall SVR rate at 24 wk post-treatment withdrawal was 59.8%. The SVR was 65.9% in the TPV group and 44.1% in the BOC group. Independent predictive factors of an SVR included a response to previous treatment, relapsers vs null-responders [OR = 3.9; (1.4, 10.6), P = 0.0084], a rapid virological response (RVR) [OR 6.9 (2.6, 18.2), P = 0.001] and liver stiffness lower than 21.3 kPa [OR = 8.2 (2.3, 29.5), P = 0.001]. During treatment, 63 patients (50.8%) had at least one severe adverse event (SAE) of grade 3 or 4. A multivariate analysis identified two factors associated with SAEs: female gender [OR = 2.4 (1.1, 5.6), P = 0.037] and a platelet count below 150 × 10³/ mm³ [OR = 5.3 (2.3, 12.4), P≤ 0.001].

CONCLUSION: More than half of these difficult-to-treat patients achieved an SVR and had SAEs in an actual practice setting. The SVR rate was influenced by the response to previous PR treatment, the RVR and liver stiffness.

Treatment of chronic HCV genotype 1 infection with telaprevir: a Bayesian mixed treatment comparison of fixed-length and response-guided treatment regimens in treatment-naïve and -experienced patients

Background

Telaprevir (TVR) has been approved for response-guided-therapy (RGT) of chronic hepatitis C (HCV) genotype-1-infection in treatment-naïve and –experienced patients. In RGT-regimens patients that did not achieve extended rapid-virological-response (eRVR) within the first 4–12 weeks undergo treatment for 48-weeks, whereas in fixed-length-treatment (FLT) patients are treated for a fixed-duration regardless of their RVR.

Methods

This systematic review and Bayesian mixed-treatment-comparison (MTC) aimed to compare the efficacy and safety of standard-therapy with pegylated-interferon-α/ribavirin (Peg-IFN-α/RBV (48 weeks), group A), FLT with TVR, Peg-IFN-α/RBV for 12 weeks with a long (+36 weeks, group B) or short (+12 weeks, group C) tail of Peg-IFN-α/RBV treatment, and RGT with 12 weeks of TVR, Peg-IFN-α/RBV followed by 12 weeks of Peg-IFN-α/RBV (group D) or no therapy (group E).

Results

We identified seven randomized controlled trials including 3505 patients. Compared to standard-treatment (group A), treatment-naïve patients allocated to groups B, C, and D were significantly more likely to achieve sustained-virological-response (SVR, odds ratios (OR): B vs. A 3.5 (credibility interval [CrI] 2.2-5.4), C vs. A 3.0 (CrI 1.8-4.9), D vs. A 3.4 (CrI 2.5-4.6)). Treatment-experienced patients achieved increased SVR rates when they were treated in group B (OR: 8.2 (CrI 5.0-13.5)), C (OR 7.0 (CrI 3.9-12.8)), or simulated group D (OR 8.2 (CrI 4.3-15.3)). Patients treated with short RGT (simulated group E) did also have a significant improvement when they were treatment-experienced (simulated OR 3.6 (CrI 1.6-8.2)), whereas the effect was not significant in treatment-naïve patients (OR E vs. A 1.6 (CrI 0.9-2.7)).

Conclusion

Long FLT and RGT regimens are useful treatment options for HCV-genotype-1 in both treatment-naïve and -experienced patients. A short 24-weeks FLT regimen does not seem to be inferior and should further be evaluated in clinical trials to reduce side effects and costs of treatment.

The utility of modeling and simulation in drug development and regulatory review

US Food and Drug Administration (FDA) has identified innovation in clinical evaluations as a major scientific priority area. This paper provides case studies and updates to describe the efforts by the FDA's Office of Clinical Pharmacology in its development and application of regulatory science, focusing on modeling and simulation. Key issues and challenges are identified that need to be addressed to promote the uptake of modeling and simulation approaches in drug regulation. Published 2013. This article is a U.S. Government work and is in the public domain in the USA. 102:2912-2923, 2013.

Treatment of chronic hepatitis C virus infection in Japan: update on therapy and guidelines

Hepatitis C virus (HCV) infection is a serious health problem leading to cirrhosis, liver failure and hepatocellular carcinoma. The recent introduction of telaprevir, which was approved in November 2011, in combination with peg-interferon and ribavirin is expected to markedly improve the eradication rate of the virus. However, side effects of triple therapy may be severe. In a phase three III clinical trial, 2250 mg of telaprevir, which is the same dosage used in clinical trials in Western countries, was given to Japanese patients. As this dosage is considered to be relatively high for Japanese patients, who typically have lower weight than patients in Western countries, reduction of telaprevir is recommended in the 2012 revision of the guidelines established by the Study Group for the Standardization of Treatment of Viral Hepatitis Including Cirrhosis published by the Ministry of Health, Labour and Welfare of Japan. Other protease inhibitors with fewer side effects are now in clinical trials in Japan. Alternatively, treatment of patients with combination of direct acting antivirals without interferon has been reported. In this review we summarize current treatment options in Japan and discuss how we treat patients with chronic HCV infection.