Pivotal Phase 3 Studies of Bezlotoxumab, Merck's Investigational Antitoxin to Prevent Clostridium Difficile Infection Recurrence, Met Primary Endpoint

Company Plans to Submit New Drug Applications in U.S., EU and Canada in 2015

Results Presented for the First Time at ICAAC/ICC 2015 Annual Meeting

September 20, 2015 12:30 PM Eastern Daylight Time
KENILWORTH, N.J.--(BUSINESS WIRE)--Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced that the two pivotal Phase 3 clinical studies for bezlotoxumab, its investigational antitoxin for prevention of Clostridium difficile (C. difficile) infection recurrence, met their primary efficacy endpoint: the reduction in C. difficile recurrence through week 12 compared to placebo, when used in conjunction with standard of care antibiotics for the treatment of C. difficile. Based on these results, the company plans to submit new drug applications seeking regulatory approval of bezlotoxumab in the U.S., EU and Canada in 2015. Currently, there are no therapies approved for the prevention of recurrent disease caused by C. difficile.

"Results of these studies showed that a single, one-time infusion of the antitoxin bezlotoxumab given with standard of care C. difficile antibiotic treatment significantly reduced the recurrence of C. difficile infection compared to standard of care alone, and demonstrated this benefit over a 12-week period"

Results from the studies were presented for the first time at the Interscience Conference of Antimicrobial Agents and Chemotherapy (ICAAC) and International Congress of Chemotherapy and Infection (ICC) joint meeting in San Diego, Sept. 17-21.

"Results of these studies showed that a single, one-time infusion of the antitoxin bezlotoxumab given with standard of care C. difficile antibiotic treatment significantly reduced the recurrence of C. difficile infection compared to standard of care alone, and demonstrated this benefit over a 12-week period," said Dr. Mark Wilcox, Leeds Teaching Hospitals and University of Leeds, U.K., and a lead investigator for the studies. "These results were also demonstrated in patient subgroups known to be at high risk for C. difficile recurrence."

Bezlotoxumab is not an antibiotic. It is a selective, fully-human, monoclonal antibody designed to neutralize C. difficile toxin B, a toxin that can damage the gut wall and cause inflammation, leading to the symptoms of C. difficile enteritis, which include abdominal pain and watery diarrhea. Bezlotoxumab was developed by researchers at the University of Massachusetts Medical School's MassBiologics Laboratory in conjunction with Medarex (now part of Bristol-Myers Squibb), and licensed to Merck in 2009 for development as a potential therapeutic for C. difficile infection.

"Recurrence is a major challenge with C. difficile infection, and novel approaches are needed to help prevent the cycle of C. difficile recurrence," said Dr. Dale Gerding, professor of medicine, Loyola University Chicago Stritch School of Medicine, Maywood, Ill., and a lead investigator for the studies.

About the pivotal Phase 3 studies

Two global, Phase 3, double-blind studies were conducted to evaluate bezlotoxumab, either alone or in combination with actoxumab (a fully human monoclonal antibody against C. difficile toxin A), compared to placebo for the prevention of recurrent C. difficile infection in patients on standard of care antibiotics for a primary or recurrent C. difficile infection. The MODIFY I study (MONOCOLONAL ANTIBODIES FOR C. DIFFICILE THERAPY) enrolled 1452 patients (median age 65 years) in 19 countries and the MODIFY II study enrolled 1203 patients (median age 67 years) in 17 countries. The studies were conducted in both hospital and outpatient settings, and the primary endpoint for each study was evaluated through 12 weeks following study drug administration.

In the MODIFY I study, patients receiving standard of care antibiotics for C. difficile were randomized to receive a single, one-time infusion of either bezlotoxumab (10 mg/kg) (n=403), actoxumab (10 mg/kg) (n=242), the combination of bezlotoxumab and actoxumab (10 mg/kg each) (n=403) or placebo (n=404). The actoxumab arm was stopped for efficacy and safety reasons after an interim analysis. In the MODIFY II study, patients receiving standard of care antibiotics for C. difficile were randomized to receive a single, one-time infusion of either bezlotoxumab (10 mg/kg) (n=407), bezlotoxumab and actoxumab (10 mg/kg each) (n=397) or placebo (n=399).

In both MODIFY I and MODIFY II, the rate of C. difficile infection recurrence through week 12, the primary efficacy endpoint, was significantly lower in the bezlotoxumab arms (17.4%, p=0.0003) and (15.7%; p=0.0003), and the combination bezlotoxumab and actoxumab arms (15.9%, p<0.0001) and (14.9%, p<0.0001), compared to the placebo arms (27.6%) and (25.7%), respectively. In MODIFY I and MODIFY II, 1396 and 1163 patients were evaluated in the full analysis sets, respectively.

In both studies, the rate of C. difficile infection recurrence was lower in the bezlotoxumab arms compared to the placebo arms in patient subgroups known to be at high risk for C. difficile recurrence, including patients with any prior episode(s) of C. difficile infection within the previous six months, patients infected with the BI/NAP1/027 strain, patients with severe C. difficile infection (Zar score ≥ 2), patients 65 years of age or older, and patients with compromised immunity. These subpopulation analyses were pre-specified in the protocol for each study.

In the studies, the adverse reaction rates were comparable across the bezlotoxumab and placebo arms. In MODIFY I, the most common adverse reactions through four weeks after infusion (nausea, diarrhea and pyrexia) occurred at similar rates in the bezlotoxumab group (7.4%, 6.7% and 5.6%) and the placebo group (6.5%, 5.0% and 2.8%). In MODIFY II, the most common adverse reactions through four weeks after infusion (nausea, diarrhea and urinary tract infection) occurred at similar rates in the bezlotoxumab group (5.8%, 5.3% and 4.5%) and the placebo group (3.4%, 6.6% and 4.2%). Additionally, rates of serious adverse reactions and deaths assessed through 12 weeks after infusion were comparable across these treatment arms.

Treatment with the combination of bezlotoxumab and actoxumab did not provide added efficacy over bezlotoxumab alone. Furthermore, actoxumab alone provided no benefit in the prevention of C. difficile recurrence compared with placebo. Based on these results, bezlotoxumab alone was selected for the marketing authorization application.

About C. difficile infection

The incidence of C. difficile infection has risen sharply over the last two decades and today is a leading cause of healthcare-acquired infections in community hospitals in the U.S. According to the U.S. Centers for Disease Control and Prevention (CDC), C. difficile is estimated to have caused almost half a million infections in the U.S. in 2011, with 29,000 deaths, often occurring within 30 days of initial diagnosis. In the U.S., 8 out of 10 deaths related to C. difficile infection occur in patients 65 years of age or older.

C. difficile infection occurs most often in patients staying in healthcare settings, especially hospitals or nursing homes, who recently took certain antibiotics or other medications. The incidence of C. difficile infection is higher in certain patient populations, including people 65 years of age or older, and in patients with compromised immune systems due to an underlying disease or from treatment. Recurrence is a major challenge in C. difficile infection, with approximately one-in-four patients experiencing a recurrence after the initial episode, and more than 40 percent of these patients having further C. difficile recurrence.

About Merck

Today's Merck is a global healthcare leader working to help the world be well. Merck is known as MSD outside of the United States and Canada. 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 healthcare through far-reaching policies, programs and partnerships. For more information, visit www.merck.com and connect with us on Twitter, Facebook and YouTube.

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. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company's 2014 Annual Report on Form 10-K and the company's other filings with the Securities and Exchange Commission (SEC) available at the SEC's Internet site (www.sec.gov).

Contacts
Merck
Media Contacts:
Doris Li, 908-246-5701
Ian McConnell, 973-901-5722
or
Investor Contacts:
Teri Loxam, 908-740-1986
Justin Holko, 908-740-1879

Suggested Articles

The action will see Kiadis switch its attention to earlier-stage natural killer cell therapies against solid tumors and hematological cancers.

The Weill Family Foundation is stumping up $106 million to create a so-called “Neurohub.”

The takeover centers on TRPML1 agonists designed to treat neurodegenerative disorders by clearing toxic proteins from the brain.