New Data Presented at ACTRIMS Forum 2021 Indicate MAVENCLAD®-treated RMS Patients Mount Protective Antibody Response to Common Vaccines

DARMSTADT,Germany,Feb. 25,2021 --

Not intended for UK and U.S. based media

Merck,a leading science and technology company,today announced the presentation of a new analysis from the MAGNIFY-MS study on MAVENCLAD® (cladribine tablets) in patients with relapsing multiple sclerosis (RMS) at the Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) Forum 2021,being held virtually 25-27 February 2021. The data indicate that RMS patients receiving MAVENCLAD are able to mount a responseto seasonal influenza and varicella zoster vaccination.

"Understanding vaccine efficacy in MS patients is particularly important in the face of the current pandemic and the growing availability of COVID-19 vaccines," said Klaus Schmierer,Professor of Neurology at Queen Mary University of London and The Royal London Hospital,UK. "Whilst this new information is based on a small cohort of patients receiving influenza and varicella zoster vaccines,it provides physicians with preliminary evidence that patients taking MAVENCLAD are able to mount and maintain effective vaccine responses."

The retrospective analysis was conducted to evaluate the protective antibody response to seasonal influenza (n=12) and varicella zoster virus (VZV) vaccination (n=3) in patients treated with MAVENCLAD. Blood samples taken before and after vaccination were examined. In patients who received the seasonal influenza vaccine,protective antibody levels were maintained or increased for at least six months independent of lymphocyte counts measured at the time of vaccination in year 1 or 2 of MAVENCLAD treatment. In patients who received the VZV vaccine before year 1 initiation of MAVENCLAD,protective VZV antibody levels were maintained over six months post-initiation with MAVENCLAD,despite lymphocyte depletion. These results were consistent irrespective of when the patients received the vaccine relative to their MAVENCLAD treatment.

In the CLOCK-MS vaccine sub-study analysis,three relapsing remitting multiple sclerosis (RRMS) patients had received at least one dose of MAVENCLAD prior to receiving an influenza vaccine. Protective antibody levels were increased at four weeks post-vaccination in all three patients. Two of these patients,who had received treatment with MAVENCLAD two and four months prior to vaccination,were experiencing lymphopenia around the time of vaccination.

"In an ever changing world where a pandemic will likely be present for the foreseeable future,it is critical to assess the impact of common non-live vaccinations in those taking disease modifying therapies," said Maria Rivas,MD,Chief Medical Officer,Healthcare business of Merck. "We are committed to communicating timely real-world evaluations of our therapies to help answer relevant questions raised by the MS community."

About MAVENCLAD®

MAVENCLAD®is a short-course oral therapy that selectively and periodically targets lymphocytes thought to be integral to the pathological process of relapsing MS (RMS). In August 2017,the European Commission (EC) granted marketing authorization for MAVENCLAD® for the treatment of relapsing forms of multiple sclerosis (RMS) in the 28 countries of the European Union (EU) in addition to Norway,Liechtenstein and Iceland. MAVENCLAD®has since then been approved in over 80 countries,including Canada,Australia and the U.S. Refer to the respective prescribing information for further details.

The clinical development programme for cladribine tablets includes:

The CLARITY (Cladribine Tablets Treating MS Orally) study: a two-year Phase III placebo-controlled study designed to evaluate the efficacy and safety of cladribine tablets as a monotherapy in patients with RRMS.

The CLARITY extension study: a Phase III placebo-controlled study following on from the CLARITY study,which evaluated the safety and exploratory efficacy of cladribine tablets over two additional years beyond the two-year CLARITY study,according to the treatment assignment scheme for years 3 and 4.

The ORACLE MS (Oral Cladribine in Early MS) study: a two-year Phase III placebo-controlled study designed to evaluate the efficacy and safety of cladribine tablets as a monotherapy in patients at risk of developing MS (patients who have experienced a first clinical event suggestive of MS).

The ONWARD (Oral Cladribine Added ON to Interferon beta-1a in Patients With Active Relapsing Disease) study: a Phase II placebo-controlled study designed primarily to evaluate the safety and tolerability of adding cladribine tablets treatment to patients with relapsing forms of MS,who have experienced breakthrough disease while on established interferon-beta therapy.

PREMIERE (Prospective Observational Long-term Safety Registry of Multiple Sclerosis) study: a long-term observational follow-up safety registry of MS patients who participated in cladribine tablets clinical studies.

In the two-year CLARITY study,the most commonly reported adverse event (AE) in patients treated with cladribine tablets was lymphopenia (26.7% with cladribine tablets and 1.8% for placebo). The incidence of infections was 48.3% with cladribine tablets and 42.5% with placebo,with 99.1% and 99.0% respectively rated mild-to-moderate by investigators.Adverse Events reported in other clinical studies were similar.

About Multiple Sclerosis

Multiple sclerosis (MS) is a chronic,inflammatory condition of the central nervous system and is the most common non-traumatic,disabling neurological disease in young adults. It is estimated approximately 2.8 million people have MS worldwide. While symptoms can vary,the most common symptoms of MS include blurred vision,numbness or tingling in the limbs and problems with strength and coordination. The relapsing forms of MS are the most common.

Merck in Neurology and Immunology

Merck has a long-standing legacy in neurology and immunology,with significant R&D and commercial experience in multiple sclerosis (MS). The company`s current MS portfolio includes two products for the treatment of relapsing MS – Rebif® (interferon beta-1a) and MAVENCLAD® (cladribine tablets). Merck aims to improve the lives of patients by addressing areas of unmet medical needs. In addition to Merck's commitment to MS,the company also have a pipeline focusing on discovering new therapies that have the potential in other neuroimmune diseases.

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About Merck

Merck,operates across healthcare,life science and performance materials. Around 58,000 employees work to make a positive difference to millions of people's lives every day by creating more joyful and sustainable ways to live. From advancing gene editing technologies and discovering unique ways to treat the most challenging diseases to enabling the intelligence of devices – the company is everywhere. In 2019,Merck generated sales of € 16.2 billion in 66 countries.

Scientific exploration and responsible entrepreneurship have been key to Merck's technological and scientific advances. This is how Merck has thrived since its founding in 1668. The founding family remains the majority owner of the publicly listed company. Merck holds the global rights to the Merck name and brand. The only exceptions are the United States and Canada,where the business sectors of Merck operate as EMD Serono in healthcare,MilliporeSigma in life science,and EMD Performance Materials.

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