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Telaprevir Combination Therapy Boosts Sustained Response Rates for Previously Treated Hepatitis C Patients

SUMMARY: Vertex Pharmaceuticals this week released new data from the Phase 3 REALIZE trial showing that about two-thirds of treatment-experienced genotype 1 chronic hepatitis C patients achieved sustained virological response (SVR) when re-treated with regimens containing the experimental HCV protease inhibitor telaprevir plus pegylated interferon and ribavirin -- about 4 times as many as did so using standard therapy alone.


Researchers are studying a number of oral drug candidates that directly interfere with hepatitis C virus (HCV) replication. To date, most clinical trials have combined these drugs with pegylated interferon (Pegasys or PegIntron), with or without ribavirin, which stimulates immune system activity against the virus. Adding direct-acting agents to standard therapy may improve response rates and shorten the total length of treatment.

Among these experimental compounds, telaprevir -- which interferes with the HCV protease enzyme -- is furthest along in the drug development pipeline. Vertex has indicated that it expects to complete its application for Food and Drug Administration (FDA) approval by the end of the year.

Below is an edited excerpt from a Vertex press release describing the REALIZE trial and its most recent findings.

65% of People Whose Prior Treatment for Hepatitis C Was Unsuccessful Achieved SVR (Viral Cure) with Telaprevir-Based Therapy in Phase 3 REALIZE Study

17% of people achieved SVR with pegylated-interferon and ribavirin alone in the control arm
Safety and tolerability results were consistent with prior Phase 3 studies
Completion of rolling New Drug Application submission on track for the fourth quarter 2010

Cambridge, Mass. -- September 7, 2010 -- Vertex Pharmaceuticals Incorporated (Nasdaq: VRTX) today announced that 65% of people overall achieved a sustained viral response (SVR or viral cure) with a telaprevir-based regimen in the pivotal Phase 3 REALIZE study, as compared to 17% of people in the control arm who received pegylated-interferon and ribavirin alone. REALIZE enrolled three groups of patients with genotype 1 hepatitis C who had undergone at least one prior treatment course with pegylated interferon and ribavirin but did not achieve SVR: (1) those who relapsed, (2) those who achieved a partial response and (3) those who had almost no response, known as a null response. REALIZE is the only Phase 3 hepatitis C study to date of an investigational direct-acting antiviral therapy that was designed to evaluate all major subgroups of people whose prior treatment was unsuccessful, including those who had a null response. The safety and tolerability results were consistent with results from the other two Phase 3 studies of telaprevir. The REALIZE study was conducted by Vertex's collaborator, Tibotec.

"The REALIZE data represent a major milestone in the development of new treatments for hepatitis C, as patients who received telaprevir-based therapy had a viral cure rate almost four times greater than the cure rate in those treated with available medicines," said Stefan Zeuzem, MD, Professor of Medicine and Chief of the Department of Medicine at the JW Goethe University Hospital, Frankfurt, Germany and Principal Investigator of the trial. "These results may provide hope to people who have not been cured and who are in need of new treatment options, including those with advanced liver disease."

"Along with results from ADVANCE and ILLUMINATE, the REALIZE data provide us with a strong understanding of telaprevir's potential role in helping many people with hepatitis C achieve a cure, regardless of their treatment history," said Robert Kauffman, MD, PhD, Senior Vice President and Chief Medical Officer for Vertex. "With these data, we look forward to completing our rolling New Drug Application submission for telaprevir later this year."

Overview of SVR Results


The primary endpoint of the study was SVR in each of the two telaprevir arms compared to the control arm, as well as across the three subgroups of people included in the study. One of the telaprevir treatment arms was designed to evaluate, for the first time, whether there was any further improvement in viral cure rates when delaying the start of telaprevir by four weeks, during which time patients received four weeks of pegylated interferon and ribavirin alone, compared to a simultaneous start. The SVR rates between these two arms were similar and there was no clinical benefit to the telaprevir delayed start treatment arm in any of the subgroups of patients. The table below combines the two telaprevir arms compared to the control.

 
Relapsers
(n=354)
Partial Responders
(n=124)
Null
Responders
(n=184)
Overall (ITT)
(n=662)
Telaprevir-
based
Treatment
Arms+
86%*
(n=245/286)
57%*
(n=55/97)
31%*
(n=46/147)
65%*
(n=346/530)
Pooled Analysis: 78% (n=300/383)**
Control
Arm++
24%
(n=16/68)
15%
(n=4/27)
5%
(n=2/37)
17%
(n=22/132)
Pooled Analysis: 21% (n = 20/95)**
*Combined endpoint analysis: The SVR rates observed in the overall combined telaprevir-based arms were statistically significant when compared with the control arm (p < 0.0001). Additionally, the SVR rates observed in each of the three groups of patients evaluated were statistically significant when compared with the control arm (relapsers and partial responders (p<0.0001) and null responders (p<0.001)).
+Reflects SVR rates from the combined telaprevir-based treatment groups. There were two telaprevir-based treatment groups:
1. 12 weeks of telaprevir (750 mg, q8h), pegylated-interferon (Peg-IFN) & ribavirin (RBV), followed by 36 weeks of Peg-IFN & RBV alone or
2. 4 weeks of Peg-IFN & RBV alone followed by 12 weeks of telaprevir (750 mg, q8h), Peg-IFN & RBV, followed by 32 weeks of Peg-IFN & RBV alone
++12 weeks of placebo, Peg-IFN & RBV, followed by 36 weeks of Peg-IFN and RBV alone
**Supplemental analysis
Null Responder: Defined as a person who achieved a less than 2 log10 reduction in HCV RNA at week 12 of a prior course of therapy.
Relapser: Defined as a person whose hepatitis C virus was undetectable at the completion of at least 42 weeks of a prior course of therapy but whose virus became detectable during the follow-up period.
Partial Responder: Defined as a person who achieved at least a 2 log10 reduction at week 12, but whose hepatitis C virus never became undetectable by week 24 of a prior course of therapy.
Backgrounders on hepatitis C treatment response and the REALIZE study (including trial design diagram) can be found at http://investors.vrtx.com/press.cfm.

SVR rates for the telaprevir simultaneous start arm and the delayed start arm were 64% and 66%, respectively, overall, based on an intent-to-treat (ITT) analysis. For the primary analysis, the SVR rates for the telaprevir simultaneous start arm, delayed start arm and control arm, respectively, were 83%, 88% and 24% in relapsers (p<0.0001); 59%, 54% and 15% in partial responders, (p<0.0001); and 29%, 33% and 5% in null responders, (p<0.001).

Safety & Tolerability Results


The safety and tolerability results of the telaprevir-based regimens in the REALIZE study were consistent with results reported from the Phase 3 ADVANCE and ILLUMINATE studies. The most common adverse events, reported in any treatment arm during the telaprevir dosing periods and up to week 16 to account for the telaprevir delayed start arm in order of frequency, were fatigue, pruritis [itching], headache, rash, flu-like symptoms, nausea and anemia, with the majority being mild to moderate. Of these, fatigue, pruritis, rash, flu-like symptoms, nausea and anemia were more common in the telaprevir-based treatment arms compared to control. Adverse events leading to discontinuation of all study drugs during the telaprevir dosing period and up to week 16 occurred in 4% of people in the combined telaprevir arms and 3% in the control arm during the same period. Discontinuation of all drugs due to anemia and rash during the telaprevir dosing period and up to week 16 occurred in 0.6% and 0.4% of patients, respectively, in the combined telaprevir arms, while discontinuation of all three drugs due to rash and anemia did not occur in the control arm during the same period. As in ADVANCE and ILLUMINATE, the use of erythropoiesis-stimulating agents (ESAs) was not allowed in this study.

Telaprevir is an investigational, oral inhibitor of HCV protease, an enzyme essential for viral replication, and is being developed by Vertex Pharmaceuticals in collaboration with Tibotec Pharmaceuticals and Mitsubishi Tanabe Pharma. With results from the three Phase 3 studies of telaprevir -- ADVANCE, ILLUMINATE and REALIZE -- Vertex is on track to complete its rolling New Drug Application (NDA) submission to the U.S. Food and Drug Administration (FDA) in the fourth quarter of 2010.

Patient Demographics

REALIZE enrolled people with hepatitis C who did not achieve a viral cure after receiving at least one course of prior treatment with pegylated-interferon and ribavirin. Patients in the study were enrolled based on their response to prior treatment: 53% were prior relapsers, 19% were prior partial responders and 28% were prior null responders. In this study, 26% of patients overall had cirrhosis and 89% of patients overall had a high viral load (HCV RNA greater than or equal to 800,000 IU/mL) when entering the study. Specifically in the null responder population, there were an even greater number of people with cirrhosis (33%) and high viral load (95%). Approximately 50% of patients were genotype 1a and 50% were genotype 1b.

About the Study

REALIZE was a pivotal Phase 3, randomized, double-blind, placebo-controlled study conducted in 662 people at more than 100 international clinical trial sites with the majority in Europe and North America. The study was designed to evaluate the efficacy, safety and tolerability of telaprevir-based regimens in people infected with genotype 1 chronic hepatitis C who did not achieve a viral cure after at least one prior treatment with interferon-based therapy. There were two telaprevir-based arms (simultaneous and delayed start) and one control arm. Patients were randomized 2:2:1 to the two telaprevir arms and the control arm, respectively.

The primary endpoint of the REALIZE study was SVR, defined as the proportion of people who had undetectable HCV RNA (< 25 IU/mL undetectable by Roche COBAS Taqman HCV test) 24 weeks after the end of all treatment. REALIZE was designed to compare the SVR rates for each of the telaprevir-based regimens with the control arm, separately for the prior response subgroups of relapsers and non-responders (null and partial responders), and then for the two subgroups of non-responders. The secondary endpoint was to evaluate the safety and tolerability of telaprevir in combination with pegylated-interferon and ribavirin.

As in all Phase 3 studies of telaprevir, patients received no more than 12 weeks of telaprevir given in combination with pegylated interferon and ribavirin. In REALIZE, the telaprevir arms included 12 weeks of telaprevir in combination with pegylated-interferon and ribavirin with 36 weeks of pegylated-interferon and ribavirin alone for a total of 48 weeks of treatment.

About the Telaprevir Development Program

To date, more than 2,500 people with hepatitis C have received telaprevir-based therapy as part of Phase 2 studies and the Phase 3 ADVANCE, ILLUMINATE and REALIZE studies. Together, these studies enrolled people with genotype 1 hepatitis C who had not been treated for their disease previously as well as people who had been treated before but did not achieve a viral cure.

Vertex retains commercial rights to telaprevir in North America. Tibotec has rights to commercialize telaprevir in Europe, South America, Australia, the Middle East and certain other countries. Mitsubishi Tanabe Pharma has rights to commercialize telaprevir in Japan and certain Far East countries.

About Vertex

Vertex Pharmaceuticals Incorporated is a global biotechnology company committed to the discovery and development of breakthrough small molecule drugs for serious diseases. The Company's strategy is to commercialize its products both independently and in collaboration with major pharmaceutical companies. Vertex's product pipeline is focused on viral diseases, cystic fibrosis, inflammation, autoimmune diseases, epilepsy, cancer and pain. Vertex co-discovered the HIV protease inhibitor, Lexiva, with GlaxoSmithKline. For more information, see www.vrtx.com.

9/10/10

Source
Vertex Pharmaceuticals. 65% of People Whose Prior Treatment for Hepatitis C Was Unsuccessful Achieved SVR (Viral Cure) with Telaprevir-Based Therapy in Phase 3 REALIZE Study. Press release. September 7, 2010.


 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


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