Remembering a stem cell pioneer in the fight against HIV/AIDS

Timothy Ray Brown. Photo courtesy Seattle Times

Timothy Ray Brown, a man who was the first person to be cured of HIV, giving hope to millions of people around the world, died at his home in Palm Springs this week. He was just 54 years old.

For years Brown was known simply as “the Berlin patient” because that was where he was living when he made medical history. He was diagnosed with HIV in 1995 and began taking medications to keep the virus under control. He was later also diagnosed with leukemia. He underwent several rounds of treatment for the leukemia, but it kept recurring.

By 2007 Brown’s physician decided the best way to treat the leukemia was with a blood stem cell transplant. But the doctor also wanted to see if using the stem cells from a donor who had a natural immunity to the AIDS virus could help treat Brown’s HIV. While such donors are very rare, the doctor succeeded in finding one whose bone marrow carried the CCR5 gene, a mutation that is believed to provide resistance to HIV. The transplant was a success, putting Brown’s leukemia into remission and eliminating detectable traces of HIV. For the first time in years he was able to stop taking the medications that had helped keep the virus under control.

The procedure quickly garnered world-wide attention. But not everyone was convinced it was real. Some questioned if Brown’s HIV had really been eradicated and speculated that the virus was merely suppressed. But with each passing year, and no signs of the virus recurring, more and more people came to believe it was a cure.

Initially Brown remained in the background, preferring not to be identified. But three years after his transplant he decided he had to come forward and put a face on “the Berlin patient”. In an interview with the website ContagionLive he explained why:

“At some point, I decided I didn’t want to be the only person in the world cured of H.I.V.,” I wanted there to be more. And the way to do that was to show the world who I am and be an advocate for H.I.V.”

He proved to be a powerful advocate, talking at international conferences and serving as living-proof that stem cells could help lead to a cure for HIV.

But while he managed to beat HIV, he could not beat leukemia. He suffered relapses that required another transplant and a difficult recovery. When it returned again this time, there was little physicians could do.

But Timothy Ray Brown did get to see his hope of not being the only patient cured seemingly come true. In September of last year researchers announced they had successfully treated a second person, known as “the London patient” using the same technique that cured Brown.

While it wasn’t the role he would have chosen Brown was a pioneer. His experience showed that a deadly virus could be cured. His courage in not just overcoming the virus but in overcoming his own reluctance to take center stage and becoming a symbol of hope for millions remain and will never die.  

Since Brown’s transplant many other scientists have attempted to replicate the procedure that cured Brown, in the hopes of making it available to many more people.

CIRM has funded three clinical trials targeting HIV, two of which are still active. Dr. Mehrdad Abedi at UC Davis and Dr. John Zaia at City of Hope are both using the patient’s own blood forming stem cells to try and defeat the virus.

If they succeed, some of the credit should go to Timothy Ray Brown, the man who led the way.

Scientists Engineer Stem Cells to Fight HIV

Image of the virus that causes AIDS – courtesy NIH

If that headline seems familiar it should. It came from an article in MIT Technology Review back in 2009. There have been many other headlines since then, all on the same subject, and yet here we are, in 2020, and still no cure for HIV/AIDS. So what’s the problem, what’s holding us back?

First, the virus is incredibly tough and wily. It is constantly mutating so trying to target it is like playing a game of ‘whack a mole’. Secondly not only can the virus evade our immune system, it actually hijacks it and uses it to help spread itself throughout the body. Even new generations of anti-HIV medications, which are effective at controlling the virus, can’t eradicate it. But now researchers are using new tools to try and overcome those obstacles and tame the virus once and for all.

Dr. Scott Kitchen: Photo David Geffen School of Medicine, UCLA

UCLA researchers Scott Kitchen and Irvin Chen have been awarded $13.65 million by the National Institutes of Health (NIH) to see if they can use the patient’s own immune system to fight back against HIV.

Dr. Irvin Chen: Photo UCLA

Dr. Kitchen and Dr. Chen take the patient’s own blood-forming stem cells and then, in the lab, they genetically engineer them to carry proteins called chimeric antigen receptors or CARs. Once these blood cells are transplanted back into the body, they combine with the patient’s own immune system T cells (CAR T). These T cells now have a newly enhanced ability to target and destroy HIV.

That’s the theory anyway. Lots of research in the lab shows it can work. For example, the UCLA team recently showed that these engineered CAR T cells not only destroyed HIV-infected cells but also lived for more than two years. Now the team at UCLA want to take the lessons learned in the lab and apply them to people.

In a news release Dr. Kitchen says the NIH grant will give them a terrific opportunity to do that: “The overarching goal of our proposed studies is to identify a new gene therapy strategy to safely and effectively modify a patient’s own stem cells to resist HIV infection and simultaneously enhance their ability to recognize and destroy infected cells in the body in hopes of curing HIV infection. It is a huge boost to our efforts at UCLA and elsewhere to find a creative strategy to defeat HIV.”

By the way, CIRM helped get this work off the ground with an early-stage grant. That enabled Dr. Kitchen and his team to get the data they needed to be able to apply to the NIH for this funding. It’s a great example of how we can kick-start projects that no one else is funding. You can read a blog about that early stage research here.

CIRM has already funded three clinical trials targeting HIV/AIDS. Two of these are still active; Dr. Mehrdad Abedi at UC Davis and Dr. John Zaia at City of Hope.

Throwback Thursday: Progress towards a cure for HIV/AIDS

Welcome to our “Throwback Thursday” series on the Stem Cellar. Over the years, we’ve accumulated an arsenal of exciting stem cell stories about advances towards stem cell-based cures for serious diseases. Today we’re featuring stories about the progress of CIRM-funded research and clinical trials that are aimed at developing stem cell-based treatments for HIV/AIDS.

 Tomorrow, December 1st, is World AIDS Day. In honor of the 34 million people worldwide who are currently living with HIV, we’re dedicating our latest #ThrowbackThursday blog to the stem cell research and clinical trials our Agency is funding for HIV/AIDS.

world_logo3To jog your memory, HIV is a virus that hijacks your immune cells. If left untreated, HIV can lead to AIDS – a condition where your immune system is compromised and cannot defend your body against infection and diseases like cancer. If you want to read more background about HIV/AIDs, check out our disease fact sheet.

Stem Cell Advancements in HIV/AIDS
While patients can now manage HIV/AIDS by taking antiretroviral therapies (called HAART), these treatments only slow the progression of the disease. There is no effective cure for HIV/AIDS, making it a significant unmet medical need in the patient community.

CIRM is funding early stage research and clinical stage research projects that are developing cell based therapies to treat and hopefully one day cure people of HIV. So far, our Agency has awarded 17 grants totalling $72.9 million in funding to HIV/AIDS research. Below is a brief description of four of these exciting projects:

Discovery Stage Research
Dr. David Baltimore at the California Institute of Technology is developing an innovative stem cell-based immunotherapy that would prevent HIV infection in specific patient populations. He recently received a CIRM Quest award, (a funding initiative in our Discovery Stage Research Program) to pursue this research.

CIRM science officer, Dr. Ross Okamura, oversees Baltimore’s CIRM grant. He explained how the Baltimore team is genetically modifying the blood stem cells of patients so that they develop into immune cells (called T cells) that specifically recognize and target the HIV virus.

Ross_IDCard

Ross Okamura, PhD

“The approach Dr. Baltimore is taking in his CIRM Discovery Quest award is to engineer human immune stem cells to suppress HIV infection.  He is providing his engineered cells with T cell protein receptors that specifically target HIV and then exploring if he can reduce the viral load of HIV (the amount of virus in a specific volume) in an animal model of the human immune system. If successful, the approach could provide life-long protection from HIV infection.”

While Baltimore’s team is currently testing this strategy in mice, if all goes well, their goal is to translate this strategy into a preventative HIV therapy for people.

Clinical Trials
CIRM is currently funding three clinical trials focused on HIV/AIDS led by teams at Calimmune, City of Hope/Sangamo Biosciences and UC Davis. Rather than spelling out the details of each trial, I’ll refer you to our new Clinical Trial Dashboard (a screenshot of the dashboard is below) and to our new Blood & Immune Disorders clinical trial infographic we released in October.

dashboardblooddisorders

MonthofCIRM_BloodDisordersJustHIV.png

As you can see from these projects, CIRM is committed to funding cutting edge research in HIV/AIDS. We hope that in the next few years, some of these projects will bear fruit and help advance stem cell-based therapies to patients suffering from this disease.

I’ll leave you with a few links to other #WorldAIDSDay relevant blogs from our Stem Cellar archive and our videos that are worth checking out.

 

CIRM-Funded Clinical Trials Targeting Blood and Immune Disorders

This blog is part of our Month of CIRM series, which features our Agency’s progress towards achieving our mission to accelerate stem cell treatments to patients with unmet medical needs.

This week, we’re highlighting CIRM-funded clinical trials to address the growing interest in our rapidly expanding clinical portfolio. Today we are featuring trials in our blood and immune disorders portfolio, specifically focusing on sickle cell disease, HIV/AIDS, severe combined immunodeficiency (SCID, also known as bubble baby disease) and rare disease called chronic granulomatous disease (CGD).

CIRM has funded a total of eight trials targeting these disease areas, all of which are currently active. Check out the infographic below for a list of those trials.

For more details about all CIRM-funded clinical trials, visit our clinical trials page and read our clinical trials brochure which provides brief overviews of each trial.

Key Steps Along the Way To Finding Treatments for HIV on World AIDS Day

Today, December 1st,  is World AIDS Day. It’s a day to acknowledge the progress that is being made in HIV prevention and treatment around the world but also to renew our commitment to a future free of HIV. This year’s theme is Leadership. Commitment. Impact.  At CIRM we are funding a number of projects focused on HIV/AIDS, so we asked Jeff Sheehy, the patient advocate for HIV/AIDS on the CIRM Board to offer his perspective on the fight against the virus.

jeff-sheehy

At CIRM we talk about and hope for cures, but our actual mission is “accelerating stem cell treatments to patients with unmet medical needs.”

For those of us in the HIV/AIDS community, we are tremendously excited about finding a cure for HIV.  We have the example of Timothy Brown, aka the “Berlin Patient”, the only person cured of HIV.

Multiple Shots on Goal

Different approaches to a cure are under investigation with multiple clinical trials.  CIRM is funding three clinical trials using cell/gene therapy in attempts to genetically modify blood forming stem cells to resist infection with HIV.  While we hope this leads to a cure, community activists have come together to urge a look at something short of a “home run.”

A subset of HIV patients go on treatment, control the virus in their blood to the point where it can’t be detected by common diagnostic tests, but never see their crucial immune fighting CD4 T cells return to normal levels after decimation by HIV.

For instance, I have been on antiretroviral therapy since 1997.  My CD4 T cells had dropped precipitously, dangerous close to the level of 200.  At that level, I would have had an AIDS diagnosis and would have been extremely vulnerable to a whole host of opportunistic infections.  Fortunately, my virus was controlled within a few weeks and within a year, my CD T cells had returned to normal levels.

For the immunological non-responders I described above, that doesn’t happen.  So while the virus is under control, their T cell counts remain low and they are very susceptible to opportunistic infections and are at much greater risk of dying.

Immunological non-responders (INRs) are usually patients who had AIDS when they were diagnosed, meaning they presented with very low CD4 T cell counts.  Many are also older.  We had hoped that with frequent testing, treatment upon diagnosis and robust healthcare systems, this population would be less of a factor.  Yet in San Francisco with its very comprehensive and sophisticated testing and treatment protocols, 16% of newly diagnosed patients in 2015 had full blown AIDS.

Until we make greater progress in testing and treating people with HIV, we can expect to see immunological non-responders who will experience sub-optimal health outcomes and who will be more difficult to treat and keep alive.

Boosting the Immune System

A major cell/gene trial for HIV targeted this population.  Their obvious unmet medical need and their greater morbidity/mortality balanced the risks of first in man gene therapy.  Sangamo, a CIRM grantee, used zinc finger nucleases to snip out a receptor, CCR5, on the surface of CD4 T cells taken from INR patients.  That receptor is a door that HIV uses to enter cells.  Some people naturally lack the receptor and usually are unable to be infected with HIV.  The Berlin Patient had his entire immune system replaced with cells from someone lacking CCR5.

Most of the patients in that first trial saw their CD4 T cells rise sharply.  The amount of HIV circulating in their gut decreased.  They experienced a high degree of modification and persistence in T stem cells, which replenish the T cell population.  And most importantly, some who regularly experienced opportunistic infections such as my friend and study participant Matt Sharp who came down with pneumonia every winter, had several healthy seasons.

Missed Opportunities

Unfortunately, the drive for a cure pushed development of the product in a different direction.  This is in large part to regulatory challenges.  A prior trial started in the late 90’s by Chiron tested a cytokine, IL 2, to see if administering it could increase T cells.  It did, but proving that these new T cells did anything was illusive and development ceased.  Another cytokine, IL 7, was moving down the development pathway when the company developing it, Cytheris, ceased business.  The pivotal trial would have required enrolling 4,000 participants, a daunting and expensive prospect.  This was due to the need to demonstrate clinical impact of the new cells in a diverse group of patients.

Given the unmet need, HIV activists have looked at the Sangamo trial, amongst others, and have initiated a dialogue with the FDA.  Activists are exploring seeking orphan drug status since the population of INRs is relatively small.

Charting a New Course

They have also discussed trial designs looking at markers of immune activity and discussed potentially identifying a segment of INRs where clinical efficacy could be shown with far, far fewer participants.

Activists are calling for companies to join them in developing products for INRs.  I’ve included the press release issued yesterday by community advocates below.

With the collaboration of the HIV activist community, this could be a unique opportunity for cell/gene companies to actually get a therapy through the FDA. On this World AIDS Day, let’s consider the value of a solid single that serves patients in need while work continues on the home run.

NEWS RELEASE: HIV Activists Seek to Accelerate Development of Immune Enhancing Therapies for Immunologic Non-Responders.

Dialogues with FDA, scientists and industry encourage consideration of orphan drug designations for therapies to help the immunologic non-responder population and exploration of novel endpoints to reduce the size of efficacy trials.

November 30, 2016 – A coalition of HIV/AIDS activists are calling for renewed attention to HIV-positive people termed immunologic non-responders (INRs), who experience sub-optimal immune system reconstitution despite years of viral load suppression by antiretroviral therapy. Studies have shown that INR patients remain at increased risk of illness and death compared to HIV-positive people who have better restoration of immune function on current drug therapies. Risk factors for becoming an INR include older age and a low CD4 count at the time of treatment initiation. To date, efforts to develop immune enhancing interventions for this population have proven challenging, despite some candidates from small companies showing signs of promise.

“We believe there is an urgent need to find ways to encourage and accelerate development of therapies to reduce the health risks faced by INR patients,” stated Nelson Vergel of the Program for Wellness Restoration (PoWeR), who initiated the activist coalition. “For example, Orphan Drug designations[i] could be granted to encourage faster-track approval of promising therapies.  These interventions may eventually help not only INRs but also people with other immune deficiency conditions”.

Along with funding, a major challenge for approval of any potential therapy is proving its efficacy. While INRs face significantly increased risk of serious morbidities and mortality compared to HIV-positive individuals with more robust immune reconstitution, demonstrating a reduction in the incidence of these outcomes would likely require expensive and lengthy clinical trials involving thousands of individuals. Activists are therefore encouraging the US Food & Drug Administration (FDA), industry and researchers to evaluate potential surrogate markers of efficacy such as relative improvements in clinical problems that may be more frequent in INR patients, such as upper respiratory infections, gastrointestinal disease, and other health issues.

“Given the risks faced by INR patients, every effort should be made to assess whether less burdensome pathways toward approval are feasible, without compromising the regulatory requirement for compelling evidence of safety and efficacy”, said Richard Jefferys of the Treatment Action Group.

The coalition is advocating that scientists, biotech and pharmaceutical companies pursue therapeutic candidates for INRs. For example, while gene and anti-inflammatory therapies for HIV are being assessed in the context of cure research, there is also evidence that they may have potential to promote immune reconstitution and reduce markers associated with risk of morbidity and mortality in INR patients. Therapeutic research should also be accompanied by robust study of the etiology and mechanisms of sub-optimal immune responses.

“While there is, appropriately, a major research focus on curing HIV, we must be alert to evidence that candidate therapies could have benefits for INR patients, and be willing to study them in this context”, argued Matt Sharp, a coalition member and INR who experienced enhanced immune reconstitution and improved health and quality of life after receiving an experimental gene therapy.

The coalition has held an initial conference call with FDA to discuss the issue. Minutes are available online.

The coalition is now aiming to convene a broader dialogue with various drug companies on the development of therapies for INR patients. Stakeholders who are interested in becoming involved are encouraged to contact coalition representatives.

[i] The Orphan Drug Act incentivizes the development of treatments for rare conditions. For more information, see:  http://www.fda.gov/ForIndustry/DevelopingProductsforRareDiseasesConditions/ucm2005525.htm

For more information:

Richard Jefferys

Michael Palm Basic Science, Vaccines & Cure Project Director
Treatment Action Group richard.jefferys@treatmentactiongroup.org

Nelson Vergel, Program for Wellness Restoration programforwellness@gmail.com