Commentary on the Cure
What Happened to the Cure for Hepatitis B?
By Timothy Block, PhD, Chari Cohen, DrPH, MPH, & Maureen Kamischke - May 2020
Just 10 years ago, interest in finding a cure for hepatitis B virus (HBV) spiked. Western interest in Asia, where HBV is an enormous health problem, and the growing prosperity in China, fueled global excitement and possibility. The success of curative therapies for hepatitis C virus further raised expectations that a cure for HBV was within reach, as well. Were those expectations unrealistic? Was there over-promising? Where are we now?
We all want an HBV cure that makes people living with HBV at no greater risk for liver disease, including liver cancer, than people without HBV. Since determining if a drug can actually achieve that kind of clinical benefit would take too long (perhaps a decade or more), a more practical definition of cure has emerged. This is the “functional” cure, which relies upon specific “markers” or “surrogates” of disease. It is hoped this surrogate provides a “prediction” of a clinical cure. So, is even a “functional” cure a realistic goal?
It is now known that even the currently available medicines for HBV can achieve the sustained “off drug, sustained virological responses” embodied in the “Functional Cure,” in at least some individuals. However, this occurs in only a small number of people. We hasten to add that research is making it clearer who with HBV would be likely to experience this benefit from the currently available drugs. But more research and innovation are critical.
Recent advances in the scientific understanding of new viral and immunological antiviral targets, and new experimental systems, are leading to innovations in drug discovery. We know of at least 48 drugs currently in development, of which 27 are already in clinical trials! This is a huge leap from 2010 (See Table 1). Moreover, the new drugs are not just “me too” drugs, repurposed from research in other disease areas. Many are “First in class,” hitting HBV therapeutic targets that have never been previously attempted. This shows just how far we have come, and how much more HBV research is being conducted today compared to 10 years ago.
However, finding treatments and cures is a challenge and a long road – and we must be prepared for ups and downs. The likelihood that a specific drug for any disease or condition will be effective, let alone be a “cure,” is fairly low. Fewer than one in five drugs that make it to clinical trials are ever “approved” by the FDA for use. And we are likely going to need a combination of drugs that complement each other in order to have even a functional cure for HBV. So, we need many more than just one drug to survive the development process.
We have little doubt that important, effective new drugs that help with sustained virological responses, and greatly improve clinical outcome, are possible, and are being developed. However, as confident as we are about what is possible, we want to be honest about how difficult and expensive this process is, and the extent to which progress is constantly threatened. As new drugs fail in their clinical trials, which is inevitable, pharmaceutical and drug development companies may become frustrated. New, more “business” attractive diseases and pathogens may emerge. Business investment may lag. And each new health crisis will distract from HBV research and add additional temptations and priorities, that will distract from the cause of an HBV cure. The COVID-19 crisis is an example. HCV was a previous example. To keep the research going, we need other sources of funding support – this could include multi-country federal funding and support from corporations and nonprofit health-focused funds. Unfortunately, there continues to be little interest to prioritize hepatitis B – which is baffling for a disease the impacts almost 300 million people worldwide and kills almost 900,000 people each year. We suspect this has something to do with the lack of a global voice for hepatitis B. We need people who are impacted by hepatitis B around the globe to raise their voice and demand that hepatitis B be prioritized as a global health threat. This can help motivate country leaders and funders to put forth more resources and support towards finding a cure.
In the past decade, impressive progress toward an HBV cure has been made, but we are not there, yet. Until recently, commercial, philanthropic and government investment has lagged – and there is still not enough prioritization or funding to eliminate hepatitis B. This is a call to action for us, at the Hepatitis B Foundation, and those around the world that we engage with. We cannot let up on our effort. It is critical that organizations such as the Hepatitis B Foundation, ICE-HBV, World Hepatitis Alliance and others – as well as individuals around the world - keep up the advocacy. Together, we remain steadfast in our efforts, and hope to keep filling the pipeline of innovations, as scientists work towards finding a cure for HBV.
About the Authors
Timothy Block is president and co-Founder of the Hepatitis B Foundation and Baruch S. Blumberg Institute.
Chari Cohen is senior vice president of the Hepatitis B Foundation and associate professor of the Baruch S. Blumberg Institute.
Maureen Kamischke is director of international engagement of the Hepatitis B Foundation.