For many years, the Southeast Asian nation of Timor-Leste was endemic for lymphatic filariasis (LF, also known as elephantiasis), a debilitating parasitic disease that causes extreme and disfiguring swelling of the limbs, permanent physical disability, and psychological suffering due to stigma. The Ministry of Health started annual mass administration of two drugs (diethylcarbamazine and albendazole) in 2005 to eliminate LF by killing the parasites that cause the disease. The goal was to eliminate LF as a public health problem—but progress was slow.

In 2017, the WHO recommended a new “triple therapy” treatment strategy: adding Mectizan (ivermectin) to the other drugs to accelerate LF elimination. These medicines are donated free of charge by Merck & Co., Inc.* (Mectizan), Eisai (diethylcarbamazine), and GSK (albendazole). The Task Force for Global Health’s Mectizan Donation Program manages the donation of Mectizan and coordinates the delivery of GSK’s donation of albendazole. 

Timor-Leste’s strong leadership and hard work ensured the high treatment coverage needed to eliminate the disease, and this new strategy was successful. In October 2024, Timor-Leste became the first country implementing triple therapy to be validated by the WHO for eliminating LF as a public health problem. Its population of 1.4 million people is no longer at risk of this devastating disease, freeing future generations from suffering. The Ministry of Health continues to provide disability care for patients with LF symptoms, and continues surveillance to detect and respond to new cases should they occur. 

Timor-Leste’s success proved that triple therapy is an effective strategy, providing much-needed inspiration for other eligible countries fighting against LF. This success also influenced Merck’s decision to extend the donation of Mectizan for triple therapy for another five years through 2030.

“We celebrate the government of Timor-Leste, the endemic communities who helped distribute the medicines with high coverage, and the partners who made elimination of LF in Timor-Leste possible,” said Mectizan Donation Program director Dr. Yao Sodahlon. “This success demonstrates that elimination of LF can be achieved through the donations of these essential medicines, the commitment of the government and people of the endemic countries, and the global partnership working to end LF.”

* Merck & Co., Inc. is known as MSD outside the USA and Canada.