The search for a cure: how stem cells could eradicate the AIDS virus

It’s hard to overstate just how devastating the AIDS crisis was at its peak in the U.S. – and still is today in many parts of the world. In 1995 almost 51,000 Americans died from the disease, the numbers of new cases were at almost record highs, and there were few effective therapies against the virus.

HIV/AIDS medications

HIV/AIDS medications

Today that picture is very different. New medications and combination therapies have helped reduce the death rate, in some cases turning HIV into a chronic rather than fatal condition. But even now there is no cure.

That’s why the news that the Food and Drug Administration (FDA) has approved a clinical trial, that we are funding, aimed at eradicating HIV in the body, was so welcome. This could be an important step towards the Holy Grail of AIDS therapies, curing the disease.

The project is headed by Dr. John Zaia at City of Hope near Los Angeles. The team, with researchers from Keck Medicine of the University of Southern California (USC) and Sangamo BioSciences, plans on using an individual’s own stem cells to beat the virus.  They will remove some blood stem cells from HIV-infected individuals, then treat them with zinc finger nucleases (ZFNs), a kind of molecular scissors, snipping off a protein the AIDS virus needs to infect those cells.

It’s hoped the re-engineered stem cells, when returned to the body, will help create a new blood and immune system that is resistant to the virus. And if the virus can’t infect any new immune cells it could, theoretically, die off. Check out the video we produced a few years back about the project:

Studies in the lab show this approach holds a lot of promise. In a news release announcing the start of the clinical trial, Dr. Zaia said now it’s time to see if it will work in people:

“While we have a number of drugs that are effective in holding HIV at bay, we have nothing that cures it. In addition, for many patients, these medications come with significant long-term problems so there is a real need for a therapy that can help eradicate the virus from a patient completely. That is where our work is focused.”

Like all Phase 1 trials this one is focused on making sure this approach is safe for people, and identifying what, if any, side-effects there are from the treatment. The first group of patients to be treated consists of people with HIV/AIDS who have not responded well to the existing medications.

This is the second trial that CIRM is funding focused on curing HIV/AIDS. Our first, involving the company Calimmune, began its human clinical trial in July 2013. You can read more about that work here.

We know that the road to a cure will not be simple or straightforward. There have been too many false claims of cures or miracle therapies over the years for any of us to want to fall victim to hope and hype. It may even be that the most realistic goal for these approaches is what is called a “functional cure”, one that doesn’t eliminate the virus completely but does eliminate the need to take antiretroviral pills every day.

But when compared to the dark days of 1995, a functional cure is a world away from certain death.

Getting the right tools for the right job

Imagine a device that sits outside the body and works like a form of dialysis for a damaged liver, filtering out the toxins and giving the liver a chance to regenerate, and the patient a chance to avoid the need for a transplant.

Or imagine a method of enhancing the number of stem cells we can harvest or generate from umbilical cord blood, enabling us to use those stem cells and offer life-saving bone marrow transplants to all the patients who don’t have a matched donor.

Well, you may not have to imagine for too long. Yesterday, our governing Board approved almost $30 million in funding for our Tools and Technology Awards and two of the successful applications are for researchers hoping to turn those two ideas into reality.

The Tools n Tech awards may not have the glamor or cache of the big money awards that are developing treatments heading towards clinical trials, but they are nonetheless an essential part of what we do.

As our Board Chair Jonathan Thomas said in a news release they focus on developing new approaches or creating new ways of overcoming some of the biggest obstacles in stem cell research.

“Sometimes even the most promising therapy can be derailed by a tiny problem. These awards are designed to help find ways to overcome those problems, to bridge the gaps in our knowledge and ensure that the best research is able to keep progressing and move out of the lab and into clinical trials in patients.”

Altogether 20 awards were funded for a wide variety of different ideas and projects. Some focus on improving our ability to manufacture the kinds of cells we need for transplanting into patients. Another one plans to use a new class of genetic engineering tools to re-engineer the kind of stem cells found in bone marrow, making them resistant to HIV/AIDS. They also hope this method could ultimately be used to directly target the stem cells while they are inside the body, rather than taking the cells out and performing the same procedure in a lab and later transplanting them back.

Dr. Kent Leach, UC Davis School of Engineering

Dr. Kent Leach, UC Davis School of Engineering

One of the winners was Dr. Kent Leach from the University of California, Davis School of Engineering. He’s looking to make a new kind of imaging probe, one that uses light and sound to measure the strength and durability of bone and cartilage created by stem cells. This could eliminate the need for biopsies to make the same measurements, which is good news for patients and might also help reduce healthcare costs.

We featured Dr. Leach in one of our Spotlight videos where he talks about using stem cells to help repair broken bones that no longer respond to traditional methods.

BIO International Panel Showed Stem Cell Science Poised to Make a Difference in Medical Practice Soon

When the biotechnology trade association began holding annual conferences in 1993, they drew 1,400 to the first event. This year BIO International expected nearly 20,000 here in San Diego. Among the dozens of concurrent sessions each day of this four-day scramble, stem cells got one track on one day this year. But listening to the progress being made by our presenters yesterday, our field is set to grow at the pace this meeting has—and could dominate the medical sessions here within the next decade.

995548_10151801308142804_405229409_n

After setting the scene with our opening panel yesterday, four subsequent panels confirmed the vast near-term potential painted by the opening speakers. They revealed a field maturing rapidly and starting to be a valued research tool of the bigger companies that have dominated the biotech industry, at the same time it is starting to deliver therapies to patients.

The second panel displayed the robust power of stem cells to model disease better than animal models ever could. These cells also let researchers dive much deeper into the genetic causes of disease, particularly diseases with multiple genes involved. Anne Bang from the Sanford-Burnham Institute mentioned her role in a consortium organized by the National Institutes of Health that is looking at the many genes involved in a type of heart weakening called left ventricular hypertrophy. Because different ethnicities tend to respond differently to drugs used for the condition, the consortium teams are creating iPS-type stem cell lines from 125 Caucasian patients and 125 African-American patients with various forms of the condition.

Their goal is to personalize and improve therapy across both patients groups. The way cells behave in the lab can tell the researchers much more relevant information than most animal models, so drugs developed based off their discoveries should have a better chance of success. All four panelists agreed that the field needs enough drugs developed with these tools to show that they do indeed have a better success rate. That track record should start to develop over the next few years.

The third panel talked about the shift in the medical mindset that will happen when genetically modified stem cells can change the care of chronic diseases from daily therapy to cures. Louis Bretton of Calimmune discussed how his company is trying to do this for HIV, which we blogged about yesterday when they announced promising first phase results from their first four patients. Faraz Ali of bluebird bio showed that his company has already made this life-changing shift for two patients with the blood disorder Beta Thalassemia. Like most patients with the disease they had been dependent on regular transfusions to survive, but when they received transplants of their own stem cells genetically modified to produce the correct version of a protein that is defective in the disease, they were able to live without transfusions.

The fourth panel provided proof that the field is maturing in that they discussed the many hurdles and pitfalls in taking those final steps to prepare a cell therapy to be a commercial product. The three big hurdles—financing, regulatory approval and reimbursement by insurers—all required creativity by the companies outlined in the two case studies. They are working through them but it is anything but a straightforward path. This is the area I hear the most hand wringing about in the halls of meetings in our field.

The last panel showed that one way around some of those end stage hurdles is to reach across borders. Four panelists discussed specific examples of ways international collaborations have accelerated their work toward developing therapies. CIRM has more than 20 collaborative agreements with funding agencies around the world, many of them painstakingly nurtured by our former president Alan Trounson. He gave the final presentation of the panel talking about one of his new projects, building an international stem cell bank with enough cell lines that almost everyone could get donor cells that were immunologically matched.

Our board chair, Jonathan Thomas, moderated the last panel and ended with a tribute to Alan noting that his build-out of our international program would be one of his many lasting legacies.
Don Gibbons

BIO International Panel Showed Stem Cell Science Poised to Make a Difference in Medical Practice Soon

When the biotechnology trade association began holding annual conferences in 1993, they drew 1,400 to the first event. This year BIO International expected nearly 20,000 here in San Diego. Among the dozens of concurrent sessions each day of this four-day scramble, stem cells got one track on one day this year. But listening to the progress being made by our presenters yesterday, our field is set to grow at the pace this meeting has—and could dominate the medical sessions here within the next decade.

995548_10151801308142804_405229409_n

After setting the scene with our opening panel yesterday, four subsequent panels confirmed the vast near-term potential painted by the opening speakers. They revealed a field maturing rapidly and starting to be a valued research tool of the bigger companies that have dominated the biotech industry, at the same time it is starting to deliver therapies to patients.

The second panel displayed the robust power of stem cells to model disease better than animal models ever could. These cells also let researchers dive much deeper into the genetic causes of disease, particularly diseases with multiple genes involved. Anne Bang from the Sanford-Burnham Institute mentioned her role in a consortium organized by the National Institutes of Health that is looking at the many genes involved in a type of heart weakening called left ventricular hypertrophy. Because different ethnicities tend to respond differently to drugs used for the condition, the consortium teams are creating iPS-type stem cell lines from 125 Caucasian patients and 125 African-American patients with various forms of the condition.

Their goal is to personalize and improve therapy across both patients groups. The way cells behave in the lab can tell the researchers much more relevant information than most animal models, so drugs developed based off their discoveries should have a better chance of success. All four panelists agreed that the field needs enough drugs developed with these tools to show that they do indeed have a better success rate. That track record should start to develop over the next few years.

The third panel talked about the shift in the medical mindset that will happen when genetically modified stem cells can change the care of chronic diseases from daily therapy to cures. Louis Bretton of Calimmune discussed how his company is trying to do this for HIV, which we blogged about yesterday when they announced promising first phase results from their first four patients. Faraz Ali of bluebird bio showed that his company has already made this life-changing shift for two patients with the blood disorder Beta Thalassemia. Like most patients with the disease they had been dependent on regular transfusions to survive, but when they received transplants of their own stem cells genetically modified to produce the correct version of a protein that is defective in the disease, they were able to live without transfusions.

The fourth panel provided proof that the field is maturing in that they discussed the many hurdles and pitfalls in taking those final steps to prepare a cell therapy to be a commercial product. The three big hurdles—financing, regulatory approval and reimbursement by insurers—all required creativity by the companies outlined in the two case studies. They are working through them but it is anything but a straightforward path. This is the area I hear the most hand wringing about in the halls of meetings in our field.

The last panel showed that one way around some of those end stage hurdles is to reach across borders. Four panelists discussed specific examples of ways international collaborations have accelerated their work toward developing therapies. CIRM has more than 20 collaborative agreements with funding agencies around the world, many of them painstakingly nurtured by our former president Alan Trounson. He gave the final presentation of the panel talking about one of his new projects, building an international stem cell bank with enough cell lines that almost everyone could get donor cells that were immunologically matched.

Our board chair, Jonathan Thomas, moderated the last panel and ended with a tribute to Alan noting that his build-out of our international program would be one of his many lasting legacies.
Don Gibbons

Innovative Stem Cell Therapy for HIV Passes Milestone

Milestones are useful things. They measure how far we have come on a journey, and give us a sense that we are on the right path. One of the projects we are helping fund just passed a big milestone, and it’s given the researchers the go-ahead to move on to the next, perhaps even more important stage.

Left to Right: CIRM President and CEO C. Randal Mills, Calimmune CEO Louis Breton, Calimmume Chief Scientific Officer Geoff Symonds at today's news conference in San Diego.

Left to Right: CIRM President and CEO C. Randal Mills, Calimmune CEO Louis Breton and Calimmume Chief Scientific Officer Geoff Symonds at today’s news conference in San Diego.

The project is Calimmune’s stem cell gene modification study, which takes blood stem cells from people who are HIV-positive, genetically modifies them so they carry a gene that blocks the AIDS virus from infecting cells, and then re-introduces the modified cells to the patient. The hope is that those stem cells will then create a new blood system that is resistant to HIV.

The milestone it passed is that the Data Safety Monitoring Board (DSMB) looked at the results from the first group of four patients treated with this approach, found that there were no serious adverse events or dangerous side effects from it, and gave Calimmune the go-ahead to start treating the next group of patients.

In a news release we put out jointly with Calimmune, their CEO Louis Breton said this is a big step forward for them:

“We are very excited and encouraged by this development. This recommendation from the DSMB is an important step in bringing this one-time therapy to the patients, and takes us closer to our ultimate goal of eradicating AIDS.”

It’s a pretty big deal for us too, as our President and CEO C. Randal Mills noted in the same release:

“The mission of CIRM is to efficiently accelerate the development of stem cell treatments for patients suffering from unmet medical conditions. While still early in clinical development this announcement demonstrates real progress towards this mission. The accomplishments of Calimmune’s team is a great example of how CIRM partnerships are working to impact patient’s lives today.”

Now, just treating four people might not seem particularly impressive, after all HIV/AIDS has killed more than 25 million people worldwide and has infected another 25 million more – around 1.1 million here in the U.S. But every treatment has to begin with a simple premise, that whatever you do is not going to hurt the patient. Getting the green light from the Data Safety Monitoring Board, an independent panel of experts who review data and advise the researchers doing clinical trials, shows this approach appears to be safe.

The next step is to repeat this same process in 3 or 4 more patients but to give those patients a preconditioning regimen, treating them with a medication before returning their modified stem cells to them, to try and make the therapy more effective. This could show that the therapeutic approach, called Cal-1, is not only safe but also is working to protect patients against HIV.

If the safety data from that second group also looks good, then Calimmune can move on to the next group of patients. Each step, no matter how small, moves us ever closer to our end goal of developing a cure for HIV/AIDS.

That’s still a very distant goal right now, but with each milestone we pass it shows that we are heading in the right direction.

Want to know more about Calimmune’s path towards clinical trial? Check out Calimmune CEO Louis Breton’s recent video describing their progress towards a cure for HIV.

Kevin McCormack

Innovative Stem Cell Therapy for HIV Passes Milestone

Milestones are useful things. They measure how far we have come on a journey, and give us a sense that we are on the right path. One of the projects we are helping fund just passed a big milestone, and it’s given the researchers the go-ahead to move on to the next, perhaps even more important stage.

Left to Right: CIRM President and CEO C. Randal Mills, Calimmune CEO Louis Breton, Calimmume Chief Scientific Officer Geoff Symonds at today's news conference in San Diego.

Left to Right: CIRM President and CEO C. Randal Mills, Calimmune CEO Louis Breton and Calimmume Chief Scientific Officer Geoff Symonds at today’s news conference in San Diego.

The project is Calimmune’s stem cell gene modification study, which takes blood stem cells from people who are HIV-positive, genetically modifies them so they carry a gene that blocks the AIDS virus from infecting cells, and then re-introduces the modified cells to the patient. The hope is that those stem cells will then create a new blood system that is resistant to HIV.

The milestone it passed is that the Data Safety Monitoring Board (DSMB) looked at the results from the first group of four patients treated with this approach, found that there were no serious adverse events or dangerous side effects from it, and gave Calimmune the go-ahead to start treating the next group of patients.

In a news release we put out jointly with Calimmune, their CEO Louis Breton said this is a big step forward for them:

“We are very excited and encouraged by this development. This recommendation from the DSMB is an important step in bringing this one-time therapy to the patients, and takes us closer to our ultimate goal of eradicating AIDS.”

It’s a pretty big deal for us too, as our President and CEO C. Randal Mills noted in the same release:

“The mission of CIRM is to efficiently accelerate the development of stem cell treatments for patients suffering from unmet medical conditions. While still early in clinical development this announcement demonstrates real progress towards this mission. The accomplishments of Calimmune’s team is a great example of how CIRM partnerships are working to impact patient’s lives today.”

Now, just treating four people might not seem particularly impressive, after all HIV/AIDS has killed more than 25 million people worldwide and has infected another 25 million more – around 1.1 million here in the U.S. But every treatment has to begin with a simple premise, that whatever you do is not going to hurt the patient. Getting the green light from the Data Safety Monitoring Board, an independent panel of experts who review data and advise the researchers doing clinical trials, shows this approach appears to be safe.

The next step is to repeat this same process in 3 or 4 more patients but to give those patients a preconditioning regimen, treating them with a medication before returning their modified stem cells to them, to try and make the therapy more effective. This could show that the therapeutic approach, called Cal-1, is not only safe but also is working to protect patients against HIV.

If the safety data from that second group also looks good, then Calimmune can move on to the next group of patients. Each step, no matter how small, moves us ever closer to our end goal of developing a cure for HIV/AIDS.

That’s still a very distant goal right now, but with each milestone we pass it shows that we are heading in the right direction.

Want to know more about Calimmune’s path towards clinical trial? Check out Calimmune CEO Louis Breton’s recent video describing their progress towards a cure for HIV.

Kevin McCormack

Stem Cell Stories that Caught our Eye: Speeding Stroke Recovery, HIV Clinical Trial, New Method for Growing Heart Cells

Here are some stem cell stories that caught our eye this past week. Some are groundbreaking science, others are of personal interest to us, and still others are just fun.

Transplanting cells to speed stroke recovery. Stroke remains one of the most common forms of death and disability, yet utilization of therapies that can break down the blood clots that cause most forms of stroke lags; these therapies are only effective when used within 3 to 4 hours of the stroke but most patients arrive at the hospital too late. Now scientists from Shanghai Jiao Tong University may have a different solution that can repair damage already done.

Scientists have recently been looking to stem cell transplantation as a way to restore blood vessels or brain tissue destroyed by a stroke, but early experiments revealed limited effectiveness. In this study, which was published this week in Stem Cell Reports, the researchers coaxed embryonic stem cells further along in the development process before implanting them—which appears to have done the trick.

Using animal models, the team—led by Dr. Wei-Qiang Gao—transplanted two different types of so-called ‘precursor cells’ which have the ability to turn into the major types of brain and blood-vessel cells, the types of cells that are lost during a stroke.

Gao argues that this kind of transplantation is superior to previous methods because the two types of precursor cells can actually support each other in order to promote cell growth, and thus lays the foundation for new stem cell-based therapies to speed up recovery for stroke survivors.

CIRM-Funded Clinical Trial to Treat HIV. A team comprised of the City of Hope in Los Angeles, Sangamo Biosciences and the University of Southern California have developed an innovative approach to eradicating HIV.

With support from a CIRM grant, the researchers are developing a combination stem cell and gene therapy approach that is based on the success of the so-called “Berlin patient,” an HIV-positive man who was essentially cured after a bone-marrow transplant to treat his leukemia. In this instance, the bone marrow donor had a unique HIV-resistant mutation. The transplant transferred this mutation to the Berlin patient, and scientists have since been looking for a way to replicate this mutation on a larger scale. As explained in this week’s news release:

“Using an enzyme called a zinc-finger nuclease (ZFN), the research team can …“edit” the HIV patient’s stem cell genes so that, like the Berlin patient’s donor, they can no longer produce the protein. No protein, no HIV infection. The virus might then disappear from the body.

This study will be the first trial of ZFN technology in human stem cells. Earlier clinical studies in HIV-positive patients show that the ZFN method is generally safe when used with white blood cells called lymphocytes. And in one patient, the therapy was associated with temporary control of HIV without antiviral medication.”

The team hopes to begin testing this approach by the fall of 2014 on HIV patients who have not responded well to traditional therapies. CIRM funds a team that uses a different approach to gene editing that began a clinical trial last summer. You can read about both on our HIV fact sheet.

Building a Better Heart Cell. Stanford stem cell scientist Dr. Joseph Wu and his team have devised an improved method for generating large batches of heart muscle cells, known as cardiomyocytes, faster and cheaper than ever before. This new technique, described in the latest issue of Nature Methods, solves a long-standing problem in the field of regenerative medicine. As Wu explained in the Stanford University School of Medicine’s blog Scope:

“In order to fully realize the potential of these cells in drug screening and cell therapy, it’s necessary to be able to reliably generate large numbers at low cost….[Our] system is highly reproducible, massively scalable and substantially reduces costs to allow the production of billions of cardiomyocytes.”

This research, which was supported by a grant from CIRM, stands to improve scientists’ ability to use patient-derived cells not only to better understand how a heart becomes a heart, but also to test drugs that treat various types of heart disease.