Celebrating 35 Years of the Mectizan Donation Program (MDP): Q&A with River Blindness Experts

Thirty-five years ago, Merck & Co. Inc. was looking for a partner organization to help deliver its medicine to communities affected by river blindness. Merck had a product that had been developed to treat parasitic worms in animals. A Merck scientist, Dr. William Campbell, realized the drug may work on parasitic diseases in humans and Merck agreed to develop a human formulation. The drug was successful and then approved to treat and control river blindness (onchocerciasis), at which point the company pledged to donate the product, called Mectizan, free to affected countries “as much as needed for as long as needed.” Dr. Campbell later won a Nobel Prize for developing Mectizan. 

Merck selected The Task Force for Global Health (then called The Task Force for Child Survival) to establish the Mectizan Donation Program (MDP). The MDP team coordinates the technical and operational aspects of getting the donated medicine to the people who need it, working with a range of partners including Merck, the World Health Organization, endemic countries, and other public and private stakeholders. 

Task Force Co-Founder Dr. William Foege was instrumental in developing the early strategies to distribute Mectizan to millions of people. The Task Force provided a well-established structure and partnership model that was highly respected for its success improving childhood vaccination rates globally. MDP then pioneered a private-public partnership approach for disease-specific drug donation programs and set the stage for a new focus area on “neglected tropical diseases” in global health.

River blindness is a parasitic disease caused by bites of the black fly that breeds near fast-flowing rivers in Africa, Latin America and Yemen. It causes intense itching, visual impairment and progressive blindness. Due to the effectiveness of Mectizan and the MDP program, Colombia, Ecuador, Guatemala and Mexico have eliminated river blindness, and many other countries are on track to do the same, with specific WHO goals to achieve by 2030.  

MDP has worked with partners in more than 57 countries in Africa, Latin America, the Caribbean, the Middle East, Southeast Asia and the Western Pacific. As of December 2021, more than 4.8 billion treatments have been donated to endemic countries, reaching 400 million people annually. 

In honor of MDP’s 35th anniversary, we spoke to Dr. Yao Sodahlon, Director of the Mectizan Donation Program, and Professor B. E. B. Nwoke, Chairman of the Nigerian Onchocerciasis Elimination Committee, about the influence of the program:

As the largest and longest-running drug donation program, what are some of your reflections as MDP celebrates its 35th anniversary?

Sodahlon: The 35th anniversary is a celebration of the value of a company like Merck & Co, Inc. and its generosity. Its founder George Merck said: “We try never to forget that medicine is for the people. It is not for the profits.” I also reflect on the courage and vision of a CEO, Dr. Roy Vagelos, who decided 35 years ago that the right and most ethical business model for its newly registered medicine, Mectizan, was to make it available for free for those who need it and for as long as needed. From one CEO to the next, Merck remains fully committed to the donation of Mectizan. Making the medicines available is only part of the solution to eliminate river blindness and another parasitic disease, lymphatic filariasis. Country commitment and strong public-private partnerships are vital to bringing the medicines to those who need them—the people living “at the end of the road.”

Nwoke: MDP came at a time when the world was looking for the drug of choice to treat one of the leading causes of blindness – a disease that renders and impairs intellectual and physical growth. The involvement of MDP in the control and elimination of river blindness and lymphatic filariasis in the last 35 years is one of the best things that has happened to endemic areas. The success of MDP is impressive, to the extent that millions of people in Africa and the Americas are no longer in need of Mectizan. For instance, currently, about 10.2 million Nigerians are no longer in need of Mectizan because after consistent treatment the disease has been eliminated in some states.

Dr. Yao Sodahlon, Director of the Mectizan Donation Program, in Malawi in 2014.
Professor B. E. B. Nwoke, Chairman of the Nigerian Onchocerciasis Elimination Committee and member of the Mectizan Expert Committee.

Did MDP have to make many programmatic changes to align its goals with the WHO NTD 2021-2030 Roadmap? That roadmap was adopted in 2021, nearly three decades after the launch of MDP, and one of the significant changes was shifting the goal from simply controlling the disease to eliminating its transmission.

Sodahlon: During the period of onchocerciasis control, Mectizan treatment was limited to communities where the disease was highly prevalent and the population was at high risk of symptoms. With the paradigm shift from river blindness control to elimination of transmission, the countries need to expand treatment to all communities where the transmission is occurring, including areas where the infection rate is low, also called hypo-endemic communities. This will put more pressure on the parasite and decrease transmission of the disease faster. There is also the potential to shift from the current strategy of treating at-risk communities once annually to providing multiple rounds of treatment each year. We will continue to work with countries to forecast their short- and long-term Mectizan needs to guide Merck’s production of the medicine to ensure the supply meets the demand. 

Once river blindness and lymphatic filariasis are eliminated and MDP winds down its operations, how will countries ensure that elimination is sustained?

Sodahlon: Countries must avoid prematurely stopping treatmentFurther, once transmission is suspected to be eliminated, post-elimination surveillance must be implemented to ensure that elimination is sustained. The ideal surveillance system should be practical and easy to implement through the health system with minimal resources but robust enough to detect and promptly respond to return of infection in a community.

Nwoke: The federal Ministry of Health of an endemic country is expected to establish a process that will ensure sustainability of the program when MDP winds down its operations by improving the funding of the activities; embarking on increased high-level advocacy with  stakeholders from endemic areas, possibly with communications materials to solicit support for elimination efforts; integrating river blindness elimination activities with other NTDS as well as with other health activities; and including river blindness elimination activities in the federal Ministry of Health Integrated Diseases Surveillance Response system.

Mass drug administration in Nigeria for Mectizan.

What do you think the legacy of MDP will be?

Sodahlon: MDP will leave behind a legacy thanks to Merck’s introduction of “pharmaco-philanthropy” which raised awareness of Neglected Tropical Diseases. Indeed, building on the success of MDP, other pharmaceutical companies committed large-scale donations of medicines for other diseases, including: lymphatic filariasis (GSK donated albendazole), trachoma (Pfizer donated Zithromax), and soil-transmitted helminthiasis (J&J donated mebendazole and GSK donated albendazole). Additionally, a core strategy, “community-directed treatment with ivermectin (CDTI)”,  was developed to reach more people in need of Mectizan, especially in rural communities. The CDTI strategy is now used to distribute other health interventions, such as other NTD medicines, Vitamin A, and bed nets to prevent malaria transmission.

Nwoke: The unprecedented decision to donate Mectizan free for mass distribution for river blindness control and elimination to anyone who needed it for as long as necessary is the number one legacy. This decision was a remarkable breakthrough which revolutionized the fight against river blindness. It provided agencies, organizations and endemic countries with incentive to control and eliminate river blindness. MDP will also be remembered for increased economic development. In areas where low population densities and desertion of the fertile river valleys were caused by the impacts of  river blindness, MDP will be remembered for the increased economic development and the establishment of communities in these hitherto abandoned areas. 

To learn more, watch Mectizan Donation Program: 35 Years of Milestones.

Photos courtesy of the Mectizan Donation Program

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