Amidst spreading infectious diseases and climate change, US FDA should renew its focus on neglected tropical diseases

In 2015, the United States Food and Drug Administration (US FDA) and other Department of Health and Human Services agencies helped respond to a public health emergency concerning Zika Virus during which 5,600 cases of the virus were reported in the United States mainland and 37,000 cases in Puerto Rico and other US Territories [1].In June 2023, the US Centers for Disease Control and Prevention alerted health providers to locally acquired malaria infections in Florida and Texas [2].In October 2023, California (Pasadena) reported a case of dengue infection in a resident who apparently did not travel outside the United States [3].In November 2023, an additional case report of cutaneous leishmaniasis in Texas seemed to confirm earlier suggestions that this disease had become endemic to the US [4].These recent cases highlight one reason for US FDA to renew its past focus on developing policies and encouraging new diagnostics and treatments for neglected tropical diseases (NTDs).Though primarily focused on the United States, US FDA considers itself to have an important global role.The agency, for example, supports a global program and international offices (see e.g., https://www.fda.gov/international-programs).Yet, even though, according to the World Health Organization's 2023 Global Report on Neglected Tropical Diseases, nearly 1.65 billion people worldwide needed treatment for NTDs, and even amid such case reports as above, US FDA's response to NTDs has for many years been fairly limited in scope and prominence [5].In a well-written recent review in this journal, Mukherjee discusses US FDA programs relevant to NTDs and discusses existing or potential efforts such as additional incentive programs, enhancing the tropical disease Priority Review Voucher program, and use of authorities such as those covering orphan products that could spur additional NTD product development [6].Yet, thus far as Mukherjee points out, most attention has focused on tuberculosis and malaria that are considered NTDs under US FDA's definition but not those of the World Health Organization [5,6].As explained by Mukherjee and other sources, Section 524 of the US Federal Food, Drug and Cosmetic Act and current US FDA guidance documents define neglected tropical diseases.The US FDA's definition of NTDs includes malaria, tuberculosis, dengue/ dengue haemorrhagic fever, leishmaniasis, and soil-transmitted helminthiasis (e.g., hookworm) as well as "[a]ny other infectious disease for which there is no significant market in developed nations and that disproportionately affects poor and marginalized populations" as designated by the Secretary of the US Department of Health and Human Services [6,7].Thus, while Zika virus, tuberculosis, and malaria are considered NTDs by US FDA, they are not included on WHO's list.Conversely, snakebite envenoming is considered an NTD by WHO but not US FDA.Mukherjee points to several barriers to NTD product such as limited incentives and a difficult and lengthy process for bringing products to market [6].However, another possible