Merck Initiates Phase 3 Study of Letermovir, an Investigational Antiviral for Prevention of Cytomegalovirus (CMV) Infection in

  Merck Initiates Phase 3 Study of Letermovir, an Investigational Antiviral
  for Prevention of Cytomegalovirus (CMV) Infection in High-Risk Bone Marrow
  Transplant Patients

Business Wire

WHITEHOUSE STATION, N.J. -- July 24, 2014

Merck (NYSE:MRK), known as MSD outside the United States and Canada, today
announced that the first patient has been enrolled in a global Phase 3
clinical study of letermovir (MK-8228), an investigational antiviral agent.
The multicenter, randomized, placebo-controlled study will evaluate the
efficacy and safety of letermovir for the prevention of clinically-significant
cytomegalovirus (CMV) infection in adult (18 years and older) CMV-seropositive
recipients of allogeneic hematopoietic stem cell transplants.

“There remains a need for additional therapeutic options in the prevention of
CMV infection in high-risk patients,” said Dr. Michele Trucksis, executive
director, Infectious Diseases, Merck Research Laboratories. “Merck is pleased
to initiate this global Phase 3 study with letermovir.”

“This study marks a very important step in the development of letermovir and
for AiCuris as licensor of this compound,” said Prof. Helga Rübsamen-Schaeff,
CEO of AiCuris. “We are very excited to have reached this stage and look
forward to the results.”

In the study, letermovir will be administered once daily, either as an oral
tablet or IV formulation, for 14 weeks after transplant. The dose will be 240
mg once daily for participants receiving concomitant cyclosporin A and 480 mg
once daily for participants not receiving cyclosporin A. The primary outcome
measure of the study will be the percentage of participants with
clinically-significant CMV infection through 24 weeks after transplant who
were administered letermovir compared to placebo.

Merck expects approximately 540 patients will be enrolled in the study at more
than 70 centers in 20 countries, including the United States. The estimated
study completion date is July 2017.

To learn more about the study, please contact Merck at 1-888-577-8839 or visit Additional details can also be found online at

About letermovir

Letermovir is an investigational once-daily antiviral agent under development
for the prevention of human CMV infection. It is derived from a novel chemical
class (quinazolines) and is designed to inhibit the human CMV viral terminase.
Letermovir has been granted Orphan Product Designation by the European
Medicines Agency (EMA) and the U.S. Food and Drug Administration (FDA) for the
prevention of CMV viremia and disease in at-risk populations and also has been
granted Fast Track Status by the FDA.

Under an agreement signed in 2012, Merck (through a subsidiary) purchased
worldwide rights to develop and commercialize letermovir from AiCuris GmbH &
Co KG (

About CMV

CMV is widely spread in the human population and can cause severe,
life-threatening infections in cases of immune incompetency or immune
deficiency, such as, for example, in transplant recipients. CMV infection is
characterized by fever, leukopenia (very low white blood cell count) and
thrombocytopenia (very low platelet numbers) with or without specific organ
dysfunction. Two main strategies to prevent CMV infection in transplant
recipients at risk have been adopted: anti-CMV drug prophylaxis or
surveillance and pre-emptive treatment of transplant recipients with evidence
of CMV viremia.

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 consumer care 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 and
connect with us on Twitter, Facebook and YouTube.

Forward-Looking Statement

This news release includes “forward-looking statements” within the meaning of
the safe harbor provisions of the United States Private Securities Litigation
Reform Act of 1995. These statements are based upon the current beliefs and
expectations of Merck’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; Merck’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 Merck patents
and other protections for innovative products; and the exposure to litigation,
including patent litigation, and/or regulatory actions.

Merck 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 Merck’s 2013
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


Pam Eisele, 267-305-3558
Robert Consalvo, 908-423-6595
Joseph Romanelli, 908-423-5185
Justin Holko, 908-423-5088
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