Eisai Enters into a New Joint Research Agreement with the Broad Institute to Develop an Antimalarial Medicine

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May 30, 2017, 19:35 ET

WOODCLIFF LAKE, N.J. and CAMBRIDGE, Mass., May 30, 2017 /PRNewswire/ -- Eisai Inc., the U.S. subsidiary of Tokyo, Japan-based Eisai Co., Ltd., announced today that it has entered into a new joint research agreement with the Broad Institute, a collaborative research institute which includes researchers from the Massachusetts Institute of Technology and Harvard University, to develop a new antimalarial medicine based on anti-malarial drug targets the team identified last year.

The Eisai and Broad Joint Development Program for Antimalarial Medicines was established in September 2014 and has led to the identification and optimization of promising molecules, using hits obtained by screening Broad's compound library for antimalarials as a starting point. These compounds interact with a novel target in the malarial parasite (Phenylalanine t-RNA synthetase), which results in inhibition of protein synthesis. The compounds exhibit potent both in vitro and in vivo antimalarial activity, in the blood-, the liver-, and the transmission-stages of the parasite life cycle. These results were published in the scientific journal Nature in September 2016.¹

"We are very encouraged by the favorable progress of our collaboration with the Broad Institute and are hopeful that it will lead to a new antimalarial medicine that will benefit the millions currently in need," said Haruo Naito, CEO of Eisai Co., Ltd. "At Eisai, we are proactively working to contribute towards global health, which we consider to be our mission and a long term investment in creating a healthy and prosperous middle-income class."

Malaria is a deadly disease caused by malarial parasites and is vector-transmitted (transmitted by an infected mosquito). According to the World Health Organization, the disease led to an estimated 430,000 deaths in 2015, mostly African children.² The majority of available antimalarial medicines target the blood-stage, in which the parasites replicate within erythrocytes. There is, however, a need for medicines that target all stages of the parasite lifecycle. Parasites can also become resistant to drug treatments, and thus there is an urgent need to develop medicines that utilize new mechanisms of action.

Under this agreement, Eisai and Broad aim to generate novel compounds with improved properties by building on the base of the joint development program's results, and leveraging Broad's medicinal chemistry capabilities alongside Eisai's knowledge of pharmaceutical development. After selection of a lead optimization candidate, Eisai will have the option to an exclusive license to develop the candidate.

"If successful, this would be a novel mechanism-of-action drug that targets a protein that has never-before been targeted in anti-malarial therapeutics," said research team leader Stuart Schreiber, a founding core member of the Broad Institute and a pioneer in the field of chemical biology and novel approaches to therapeutics. "Existing drugs have been around for decades, which is one reason that resistance emerges so quickly. Eisai's commitment to working with the non-profit and academic research community to explore promising new approaches demonstrates its dedication to helping overcome a deadly medical challenge that still threatens hundreds of thousands of children in developing countries."

This joint research program is funded by the Global Health Innovative Technology Fund (GHIT Fund), an international non-profit organization headquartered in Japan.

Under its human health care (hhc) philosophy, Eisai is determined to be proactive in improving access to medicines worldwide through partnerships with governments, international organizations, and other non-profit private sector organizations. Through these collaborations, Eisai aims to make new treatments available as early as possible to patients with malaria, tuberculosis and neglected tropical diseases, and thereby further increasing the healthcare benefits provided to the patients and their families.

[Notes to editors]

1. About the Global Health Innovative Technology Fund

The first of its kind in Japan, the GHIT Fund is a public-private partnership between the Japanese government, multiple pharmaceutical companies, the Bill & Melinda Gates Foundation, the Wellcome Trust, and UNDP. Launched in April 2013 with an initial commitment of more than US$100 million and now with capital of US$145 million, the organization taps Japanese research and development (R&D) to fight neglected diseases. GHIT Fund invests and manages a portfolio of development partnerships aimed at neglected diseases that afflict the world's poorest people. GHIT Fund mobilizes Japanese pharmaceutical companies and academic and research organizations to engage in the effort to get new medicines, vaccines, and diagnostic tools to people who need them most, with Japan quickly becoming a game-changer in global health. For more information, please visit www.ghitfund.org.

2. About Malaria

Malaria is a deadly disease caused by malarial parasites that are transmitted to people through the bite of an infected mosquito. According to the World Health Organization, in 2015 alone, the disease infected approximately 212 million people and led to an estimated 430,000 deaths, mostly among African children.²

When a mosquito takes blood from a human, malarial parasites in sporozoite form that are injected with the saliva of the mosquito (1) grow in the person's liver cells (2 - 3: liver-stage) before then migrating to the blood stream and multiplying within red blood cells (4). This causes the red blood cells to rupture and the parasites to continue invading more red blood cells in a continuous cycle (4→5→6→4: blood-stage). The symptoms of malaria occur during this cycle, when the parasites have invaded the blood cells, and malaria treatment involves the use of medicines to work on the parasites at this stage. However, it is known that certain species of malaria such as Plasmodium vivax lie dormant in the liver cells (2) instead of growing, and after parasites in the bloodstream (4 - 6) are killed, these hidden parasites in the liver cells awaken later through some kind of stimulus and go on to reproduce and invade the bloodstream again, a process known as relapse.

In addition, most malarial parasites produced in red blood cells (merozoites) are asexual, and will die inside a mosquito if taken during feeding. However, some of these (6: transmission-stage) develop within red blood cells into male and female gametocytes that can reproduce inside mosquitoes (7 - 8), which leads to malaria transmission. As such, if these male and female gametocytes can be killed while in the bloodstream of humans, it is possible to block the transmission of malaria to mosquitoes.

3. About Malaria Treatments

The majority of available antimalarial medicines target the blood-stage, in which the parasites replicate within erythrocytes. Even though liver- and transmission-stages parasites do not cause malarial symptoms, they can lead to an onset or relapse by transitioning into the blood-stage, or they can further spread the disease by being transmitted to mosquitoes. As such, there is a need for antimalarial medicines which target all stages of the parasite lifecycle.

Furthermore, since malarial parasites develop a resistance to antimalarial medicines, there is an urgent need for antimalarial agents with new mechanisms of action. Currently, treatment for malaria combines rapidly-acting artemisinins with lumefantrine, amodiaquine, mefloquine and other antimalarials for durability. However, in recent years, there have been reports of strains of malaria having resistance to even the relatively new artemisinin medicines.

¹ Nobutaka Kato, et al, "Diversity-oriented synthesis yields novel multistage antimalarial inhibitors" Nature, 2016; 538, 344–349

² World Health Organization http://www.who.int/mediacentre/factsheets/fs094/en/

Eisai Inc.

At Eisai Inc., human health care (hhc) is our goal. We give our first thoughts to patients and their families, and helping to increase the benefits health care provides. As the U.S. pharmaceutical subsidiary of Tokyo-based Eisai Co., Ltd., we have a passionate commitment to patient care that is the driving force behind our efforts to discover and develop innovative therapies to help address unmet medical needs.

Eisai is a fully integrated pharmaceutical business that operates in two global business groups: oncology and neurology (dementia-related diseases and neurodegenerative diseases). Each group functions as an end-to-end global business with discovery, development, and marketing capabilities. Our U.S. headquarters, commercial and clinical development organizations are located in New Jersey; our discovery labs are in Massachusetts and Pennsylvania; and our global demand chain organization resides in Maryland and North Carolina. To learn more about Eisai Inc., please visit us at www.eisai.com/US.

Eisai Co. Ltd.

Eisai Co., Ltd. is a leading global research and development-based pharmaceutical company headquartered in Japan. We define our corporate mission as "giving first thought to patients and their families and to increasing the benefits health care provides," which we call our human health care (hhc) philosophy. With over 10,000 employees working across our global network of R&D facilities, manufacturing sites and marketing subsidiaries, we strive to realize our hhc philosophy by delivering innovative products in various therapeutic areas with high unmet medical needs, including oncology and neurology. For more information about Eisai Co., Ltd., please visit www.eisai.com.