Fred Hutch Cancer Center scientist Jennifer E. Adair, PhD, is on a mission to foster worldwide collaboration on potentially curative gene therapies.
Holder of the Fleischauer Family Endowed Chair in Gene Therapy Translation, Adair just co-authored two articles published today in Science Translational Medicine as part of a special series on global access to these therapies that she curated.
Adair recently sat down with Fred Hutch News to discuss the promise of gene therapies to cure an array of diseases, as well as the need for stakeholders around the world to join forces to develop the best possible approaches and get them to the people who need them most.
Read on for Adair's take on the breakthroughs happening in this exciting, but expensive, new field of therapy.
What exactly are gene therapies, and what diseases are they being used to treat?
A gene therapy is anything that is using genetics to drive therapeutic value of the treatment. These therapies are a big paradigm shifter because they’re not managing symptoms; they are actually treating the underlying biology that causes a disease or that causes a disease to be severe, and so in most diseases they're curative.
Broadly, they are being used to treat inherited diseases, including sickle cell disease; malignant diseases, or cancer; and some infectious diseases. They're very broadly applicable. If we understand the biology of the disease, and there is a change we could make to the DNA or some type of genetic element we could add that could undo that biology, there will be a gene therapy for that disease at some point. So far, there are 32 gene therapies authorized globally, most in the U.S.
Being able to change the underlying biology rather than manage symptoms is an important advantage. What are the potential disadvantages of gene therapies?
In terms of health drawbacks, the field is still young. We don't yet know exactly how durable these therapies are. What it takes to actually modify the underlying biology of cells inside the human body, in the case of in vivo therapies, or outside the human body, in the case of ex vivo therapies — where we remove cells from a patient, alter them and then return them to the patient — is not trivial.
Also, these therapies are very expensive, and the health care systems in which they're being administered were not designed for one-time treatments meant to elicit lifetime cures. There's a lot of work to be done on how we actually settle the economics of these therapies so that companies who make them can still make money, but it's not costing $2 million or $3 million per treatment.
We also need to think carefully about the risk-to-benefit ratio. The first diseases for which gene therapies were developed were diseases with no treatments or cures, and they tended to be fatal. For those patients, the risk-to-benefit ratio is in favor of finding something that extends life or improves the quality of life, even if it also carries some risk. As gene therapies become more prevalent, we will have to reassess the risk-to-benefit ratio.
For example, for HIV, we have highly effective antiretroviral therapy combinations that, if patients have access and they maintain adherence, they can live a normal lifespan, and as long as their virus stays undetectable, they won’t transmit it to anyone else. At the same time, we’ve not been able to get antiretroviral therapy to the number of people required to control the virus globally, and so we do need a cure. Gene therapy might be that cure, but we would need to demonstrate the ability to control the virus without increasing patients’ risk of cancer in the future.
What was your role in the development of this special series of articles, and what prompted you to be involved?
I am the curator, meaning I came up with the what the series was going to look like, what key pieces we needed, and then solicited the authors. Over the last two years, I have been helping to assemble the articles and working with the editorial team to decide how to organize them — everything down to selecting the cover art for the May 8 issue, where the first two articles will appear.
The artwork really explains why I am involved. It’s a painting by Ugandan artists of a bus with a small number of riders, plenty of empty seats and a large queue of people who would love to get on the bus but for some reason can’t. The concept is by Moses Supercharger, and the artists are John Mary Kyambadde, Vanessa Nannyonjo and Moses Katabira. This represents what HIV means to Ugandans. The bus represents freedom from disease for people who’ve received therapies that put their HIV into remission, but it’s not accessible to most people. That is true for gene therapy right now.
There are 39 million people with HIV, and 85% of them live in sub-Saharan Africa. We may be able to cure HIV with gene therapy one day, but we will need to be able to deliver that cure to people in parts of the world that are most affected, which means we need people from those countries involved now in creating and implementing gene therapies. People on the ground locally need to be enabled to develop these treatments in the right way for their own people. Unfortunately, there are so many barriers to their participation — systemic, economic, social and geographic.
How does this relate to the Global Gene Therapy Initiative?
In 2020, with my collaborator Dr. Cissy Kityo, at the Joint Clinical Research Centre in Uganda, I co-founded the Global Gene Therapy Initiative, or GGTI, to support implementation of gene therapies in low- and middle-income countries. It’s a virtual network of international colleagues who represent every stakeholder group — from patients and caregivers to researchers, clinicians, regulators, government policymakers, investors and companies — who come together to learn from each other. We have met nearly every week for three-and-a-half years to go over something about the state of the field of gene therapy. We now have hundreds of members representing more than 30 countries on five continents.