Results of Phase 2 Study of Merck’s Investigational Beta-Lactamase Inhibitor Relebactam Presented at ICAAC/ICC 2015


September 18, 2015 2:00 pm ET

Company Initiates Pivotal Phase 3 Studies Evaluating Relebactam in Combination with Imipenem/Cilastatin for Treatment of Serious Bacterial Infections

Merck (NYSE:MRK), known as MSD outside the United States and Canada,
today announced that a Phase 2 study of relebactam, the company’s
investigational beta-lactamase inhibitor for the treatment, in
combination with imipenem/cilastatin (an approved carbapenem
antibiotic), of complicated intra-abdominal infections, met its primary
endpoint, and that Merck is now initiating pivotal Phase 3 studies. In
the Phase 2 study, relebactam in combination with imipenem/cilastatin
demonstrated noninferiority in the percentage of microbiologically
evaluable patients with favorable clinical response at the end of
intravenous therapy compared to imipenem/cilastatin alone. The addition
of relebactam is designed to restore activity of imipenem against
certain imipenem-resistant strains of Gram-negative bacteria, including Pseudomonas
and Klebsiella pneumoniae carbapenemase
(KPC)-producing Enterobacteriaceae.

The results were presented at the Interscience Conference of
Antimicrobial Agents and Chemotherapy (ICAAC) and International Congress
of Chemotherapy and Infection (ICC) joint meeting in San Diego, Sept.

“New medicines are urgently needed to address the growing threat of
antibiotic-resistant bacteria,” said Dr. Nicholas Kartsonis, associate
vice president, infectious disease clinical research, Merck Research
Laboratories. “We look forward to advancing our Phase 3 clinical program
evaluating relebactam, in combination with imipenem/cilastatin, for use
in the treatment of several complicated Gram-negative bacterial
infections, and to continue to build on Merck’s commitment to infectious

In this multicenter, double-blind Phase 2 study, 351 adult patients with
complicated intra-abdominal infections, most commonly complicated
appendicitis (53%) and complicated cholecystitis (17%), were randomized
to receive either relebactam 250mg, relebactam 125mg or placebo, each
given intravenously in combination with imipenem/cilastatin 500mg every
six hours for 4 to 14 days. The percentage of microbiologically
evaluable patients with favorable clinical response at the end of
intravenous therapy, the primary efficacy endpoint, was similar across
treatment groups: relebactam 250mg (96.3%) (n=83), relebactam 125mg
(98.8%) (n=87) and placebo (95.2%) (n=85).

Safety analysis focused on adverse events occurring while on intravenous
study therapy or during the 14 days following the end of therapy. The
most common adverse events (nausea, diarrhea and vomiting) occurred at
similar rates across treatment groups: relebactam 250mg (6.8%, 6.0%,
6.0%), relebactam 125mg (7.8%, 6.0%, 7.8%) and placebo (7.0%, 4.4%,
2.6%), respectively.

Phase 3 Clinical Program of Imipenem/Cilastatin/Relebactam Initiated

Based in part on the results of this Phase 2 study, Merck is planning to
initiate two pivotal Phase 3 clinical studies of relebactam with
imipenem/cilastatin given as a fixed-dose combination. A study comparing
imipenem/cilastatin/relebactam to colistimethate sodium in combination
with imipenem/cilastatin for the treatment of imipenem-resistant
bacterial infections, including those caused by P. aeruginosa and
KPC-producing organisms, is currently recruiting patients. Infections
evaluated in this study are hospital-acquired bacterial pneumonia,
ventilator-associated bacterial pneumonia, complicated intra-abdominal
infections and complicated urinary tract infections. (
Identifier: NCT02452047

A second Phase 3 study, which will initiate later this year, will
compare treatment with the fixed-dose combination of
imipenem/cilastatin/relebactam to piperacillin/tazobactam in patients
with hospital-acquired and ventilator-associated bacterial pneumonia. (
Identifier: NCT02493764

About Relebactam

Relebactam is an investigational intravenous, class A and C,
beta-lactamase inhibitor currently being evaluated in combination with
imipenem/cilastatin for the treatment of certain complicated
Gram-negative bacterial infections. In preclinical studies, relebactam
administered in combination with imipenem demonstrated antibacterial
activity against a broad range of Gram-negative and
beta-lactam-resistant pathogens. The U.S. Food and Drug Administration
(FDA) has designated this combination as a Qualified Infectious Disease
Product (QIDP) with designated Fast Track status for the treatment of
hospital-acquired bacterial pneumonia, ventilator-associated bacterial
pneumonia, complicated intra-abdominal infections and complicated
urinary tract infections.

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,
and connect with us on Twitter,
and YouTube.

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This news release of Merck & Co., Inc., Kenilworth, N.J., USA (the
“company”) includes “forward-looking statements” within the meaning of
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respect to pipeline products that the products will receive the
necessary regulatory approvals or that they will prove to be
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The company undertakes no obligation to publicly update any
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to differ materially from those described in the forward-looking
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Doris Li, (908) 246-5701
Ian McConnell, (973) 901-5722
Teri Loxam, (908) 740-1986
Justin Holko, (908) 740-1879

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