A new injectable could prevent malaria. What's standing in its way?

Despite significant advancements in malaria prevention tools, nearly half of the world's population remains at risk of malaria transmission. Experts continue to stress the importance of a diverse arsenal to achieve effective malaria prevention. One such promising measure is monoclonal antibodies, three of which are in different clinical trial stages and are backed by key players including the United States National Institutes of Health and the Gates Foundation. Trevor Mundel, president of global health at the Gates Foundation, described them as the newest product class for the prevention of malaria. “A monoclonal antibody or long-acting injectable drug that can deliver safe and cost-effective preventive efficacy from a single dose with a long duration of protection would address the limitations [of malaria vaccines],” Mundel said. Though health experts agree that monoclonal antibodies could be the next big thing in malaria prevention, several significant challenges stand in the way of their widespread deployment. Reluctance by the pharmaceutical industry to consider them profitable, the snail's pace of clinical trials, numerous knowledge gaps, and the herculean task of lowering their costs to enable realistic rollouts mean that it could be some time before these promising tools make their way to the communities who desperately need them. Promising results Monoclonal antibodies are molecules identified in individuals who have been exposed to the malaria parasite, either through natural infection or vaccination. Researchers then clone and refine these antibodies to develop an intervention that can effectively block the initial stage of malaria infection. With insecticides and drug treatments for malaria both facing challenges due to resistance and behavioral changes in the disease, researchers are actively studying monoclonal antibodies as alternative tools for malaria control. Neville Kisalu, who is actively involved in the development of the CIS43LS — one of two monoclonal antibodies being developed by the U.S. National Institutes of Health, said the antibody showed promising results in protecting healthy adults against the malaria parasite infection during a six-month malaria season in Mali. “The first clinical trials in humans showed the antibodies were also safe and the early results from phase 2 studies indicate high efficacy. If further trials are successful, these monoclonal antibodies could receive regulatory approval to help control malaria,” he told Devex. While praising the current malaria vaccines as "huge developments", Kayla Andrews, the scientific program leader for translational discovery at the Bill & Melinda Gates Medical Research Institute, told Devex there are still substantial gaps in coverage and timely protection which monoclonal antibodies could fill. "Not all children will be covered, and protection takes about four months from the start of the primary series," she said. Adding that monoclonal antibodies may protect infants who cannot yet receive vaccines, as well as immune-compromised individuals who need immediate protection. They could also offer a single health care touchpoint for protection, which may be advantageous for populations with limited access to health care. Slow progress Despite the potential benefits, the development and implementation of monoclonal antibodies for malaria are not progressing as rapidly as possible. Kisalu said one reason is the perception among major pharmaceutical companies that they may not be highly profitable. "I don't think they are going to be making a lot of money out of that because usually people that will benefit from it, they don't have that much money," he said. "One of the reasons why my organization exists is that for-profit organizations aren't always incentivized to put their research in areas where there is a lack of a market," Andrews explained. This lack of financial incentive can slow the progress of developing monoclonal antibodies for diseases like malaria, which predominantly affects lower-income countries. Cost is another significant challenge. Andrews emphasized the importance of affordability and accessibility, mentioning that research is ongoing to find cost-effective production methods. Ashley Birkett, director of the PATH Malaria Vaccine Initiative, agrees. Birkett told Devex that while monoclonal antibody projects show promise, “the key challenge is bringing costs down to make them accessible in Africa.” But experts remain hopeful, Andrews said in addition to ongoing clinical trials, researchers are also working on optimizing factors such as duration, cost, and dosing regimens, while also focusing on implementation science to ensure smooth integration with current malaria control efforts. She said the potential the monoclonal antibodies have to provide immediate and durable protection could significantly enhance current prevention strategies, particularly in areas where vaccines alone are insufficient, making them worth the investment. "The more effective tools that we have to fight malaria, the better," she said.