Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced the first sustained virologic response1 (SVR) results 12 weeks after completion of therapy (SVR12, considered virologic cure) from C-SURGE , an ongoing, open label Phase 2 clinical trial evaluating MK-3682B [uprifosbuvir (MK-3682)2/grazoprevir3/rusazvir4], the company’s investigational triple-combination therapy in treatment-experienced patients with hepatitis C virus (HCV) genotype (GT) 1 infection for whom treatment with approved direct-acting antiviral regimens had failed. The study showed that 100 percent (43/43) of patients who completed 16 weeks of treatment plus ribavirin (RBV) achieved SVR12 and 100 percent (49/49) of patients who completed 24 weeks of treatment achieved SVR12 (abstract PS-159). These results will be presented today at The International Liver Congress™ 2017.

"Despite the significant progress made to address the worldwide epidemic of chronic hepatitis C infection, there remains a need for additional treatment options," said Dr. Heiner Wedemeyer, lead study investigator and research group leader in the department of gastroenterology, hepatology and endocrinology at Hannover Medical School, Germany. "We are encouraged by the high virologic cure rates in the difficult-to-treat patients observed in the C-SURGE study and look forward to further evaluation of this investigational triple-combination therapy."

The Phase 2 C-SURGE study enrolled 94 patients who were randomized to receive a once-daily regimen of MK-3682B for either 16 weeks with RBV (n=45) or 24 weeks without RBV (n=49); one patient in the 16-week arm withdrew prior to starting treatment. Of the 93 patients who received treatment (full analysis set), 57 had previously received a regimen of ledipasvir/sofosbuvir (LDV/SOF) for 12 to 24 weeks, 14 had previously received LDV/SOF for 8 weeks and 22 had previously received ZEPATIER^® (elbasvir and grazoprevir) for 12 weeks. Seventy-eight patients who received treatment had at least one baseline NS5A resistance-associated substitution (RAS) at positions 28, 30, 31 or 93. Eighty patients who received treatment in C-SURGE had GT1a infection, and 40 patients had compensated cirrhosis. In the full analysis set, 98 percent of patients who received MK-3682B for 16 weeks with RBV (43/44) and 100 percent of patients who received MK-3682B for 24 weeks without RBV (49/49) achieved SVR12.

Results from the modified full analysis set, which excludes one patient in the 16-week arm who withdrew after three doses of treatment, show that 100 percent of patients receiving treatment with MK-3682B for 16 weeks with RBV (43/43) and 100 percent of patients receiving treatment with MK-3682B for 24 weeks without RBV (49/49) achieved SVR12.

Across the combined treatment arms, the most common adverse events (AEs) reported in the full analysis set were fatigue (35%), headache (13%), diarrhea (9%), rash (9%) and pruritus (5%). There were no drug-related serious AEs, and no patients discontinued treatment due to a drug-related AE.

SVR8 results from the C-SURGE study were previously presented at The Liver Meeting® 2016.

About MK-3682B

MK-3682B is Merck’s investigational triple-combination therapy in Phase 2 development for the treatment of chronic HCV infection. MK-3682B combines an HCV nucleotide analogue NS5B polymerase inhibitor (MK-3682), an HCV NS3/4A protease inhibitor (grazoprevir, MK-5172) and an HCV NS5A inhibitor (ruzasvir, MK-8408).

About ZEPATIER ^® (elbasvir and grazoprevir) 50mg/100mg Tablets

ZEPATIER is a fixed-dose combination product containing elbasvir, a HCV NS5A inhibitor, and grazoprevir, an HCV NS3/4A protease inhibitor. In the United States, ZEPATIER is indicated for the treatment of chronic HCV GT1 or 4 infection in adults. ZEPATIER is indicated for use with ribavirin (RBV) in certain patient populations.

Selected Safety Information about ZEPATIER (elbasvir and grazoprevir)

The US Prescribing Information for ZEPATIER contains a Boxed Warning about the risk of hepatitis B virus (HBV) reactivation in patients coinfected with HCV and HBV. Healthcare professionals should test all patients for evidence of current or prior HBV infection by measuring hepatitis B surface antigen (HBsAg) and hepatitis B core antibody (anti-HBc) before initiating treatment with ZEPATIER. HBV reactivation has been reported in HCV/HBV coinfected patients who were undergoing or had completed treatment with HCV direct-acting antivirals and were not receiving HBV antiviral therapy. Some cases have resulted in fulminant hepatitis, hepatic failure, and death. Healthcare professionals should monitor HCV/HBV coinfected patients for clinical and laboratory signs of hepatitis flare or HBV reactivation during HCV treatment and post-treatment follow-up. Healthcare professionals should initiate appropriate patient management for HBV infection as clinically indicated.

HBV reactivation has been reported in HBsAg positive patients and also in patients with serologic evidence of resolved HBV infection (ie, HBsAg negative and anti-HBc positive). The risk of HBV reactivation may be increased in patients receiving some immunosuppressant or chemotherapeutic agents. HBV reactivation is characterized as an abrupt increase in HBV replication manifesting as a rapid increase in serum HBV DNA level. In patients with resolved HBV infection, reappearance of HBsAg can occur. Reactivation of HBV replication may be accompanied by hepatitis, ie, increases in aminotransferase levels and, in severe cases, increases in bilirubin levels, liver failure, and death can occur.

ZEPATIER is not for use in patients with moderate or severe hepatic impairment (Child Pugh B or C). ZEPATIER is also not for use with inhibitors of organic anion transporting polypeptides 1B1/3 (OATP1B1/3) that are known or expected to significantly increase grazoprevir plasma concentrations (e.g., atazanavir, darunavir, lopinavir, saquinavir, tipranavir, cyclosporine), strong cytochrome P450 3A (CYP3A) inducers (e.g., carbamazepine, phenytoin, rifampin, St. John’s Wort), and efavirenz. If ZEPATIER is administered with RBV, healthcare professionals should refer to the prescribing information for RBV as the contraindications, warnings and precautions, adverse reactions and dosing for RBV also apply to this combination regimen.

Elevations of alanine transaminase (ALT) to greater than 5 times the upper limit of normal (ULN) occurred in 1% of subjects, generally at or after treatment week 8. These late ALT elevations were typically asymptomatic and most resolved with ongoing or completion of therapy. Healthcare professionals should perform hepatic lab testing on patients prior to therapy, at treatment week 8, and as clinically indicated. For patients receiving 16 weeks of therapy, additional hepatic lab testing should be performed at treatment week 12.

Patients should be instructed to consult their healthcare professional without delay if they have onset of fatigue, weakness, lack of appetite, nausea and vomiting, jaundice or discolored feces. Healthcare providers should consider discontinuing ZEPATIER^® (elbasvir and grazoprevir) if ALT levels remain persistently greater than 10 times ULN. ZEPATIER should be discontinued if ALT elevation is accompanied by signs or symptoms of liver inflammation or increasing conjugated bilirubin, alkaline phosphatase, or international normalized ratio.

The concomitant use of ZEPATIER with certain drugs may lead to adverse reactions or reduced therapeutic effect due to drug interactions. Certain strong CYP3A inhibitors may increase the plasma concentration of ZEPATIER, leading to possibly clinically significant adverse reactions. Moderate CYP3A inducers may decrease the plasma concentration of ZEPATIER, leading to reduced therapeutic effect and possible development of resistance. Coadministration of ZEPATIER with these drugs is not recommended. Physicians should consult the Prescribing Information for potential drug interactions.

In subjects receiving ZEPATIER for 12 weeks, the most commonly reported adverse reactions of all intensity (greater than or equal to 5% in placebo-controlled trials) were fatigue, headache and nausea. In subjects receiving ZEPATIER with RBV for 16 weeks, the most commonly reported adverse reactions of moderate or severe intensity (greater than or equal to 5%) were anemia and headache.

Selected Dosage and Administration Information for ZEPATIER

ZEPATIER is a single tablet taken once daily. The recommended dosing is 12 or 16 weeks with or without RBV, depending on HCV genotype, prior treatment history and, for patients with genotype 1a infection, presence of certain baseline NS5A resistance-associated polymorphisms. See Prescribing Information for ZEPATIER for specific dosage regimens and durations. Refer to RBV prescribing information for RBV dosing and dosage modifications when ZEPATIER is given with RBV. To determine dosage regimen and duration of ZEPATIER for genotype 1a patients, testing for the presence of virus with one or more baseline NS5A resistance-associated polymorphisms at positions 28, 30, 31, or 93 is recommended prior to initiating treatment.

Merck’s Commitment to HCV

For more than 30 years, Merck has been at the forefront of the response to the HCV epidemic. Merck’s chronic HCV clinical development programs have included more than 135 clinical trials in approximately 40 countries and have enrolled nearly 10,000 participants. As part of our longstanding leadership in infectious diseases, Merck collaborates with the scientific and patient communities to develop and deliver innovative solutions to support people living with chronic HCV worldwide.

About Merck

For more than a century, Merck, a leading global biopharmaceutical company known as MSD outside of the United States and Canada, has been bringing forward medicines and vaccines for many of the world's most challenging diseases. Through our prescription medicines, vaccines, biologic therapies and animal health products, we work with customers and operate in more than 140 countries to deliver innovative health solutions. We also demonstrate our commitment to increasing access to health care through far-reaching policies, programs and partnerships. Today, Merck continues to be at the forefront of research to advance the prevention and treatment of diseases that threaten people and communities around the world - including cancer, cardio-metabolic diseases, emerging animal diseases, Alzheimer's disease and infectious diseases including HIV and Ebola.

Forward-Looking Statement of Merck & Co., Inc., Kenilworth, N.J., USA

This news release of Merck & Co., Inc., Kenilworth, N.J., USA (the "company") includes "forward-looking statements" within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. There can be no guarantees with respect to pipeline products that the products will receive the necessary regulatory approvals or that they will prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise.

¹ Measured as HCV RNA less than 15 IU/mL.
² MK-3682 is an HCV nucleotide analogue NS5B polymerase inhibitor.
³ Grazoprevir is an HCV NS3/4A protease inhibitor (100mg).
⁴ Rusazvir (MK-8408) is an HCV NS5A inhibitor.