Wednesday, June 29, 2011
AIDS Stages of Care – Three So Far; Will Number Four Come Soon?
It would be only a few years, 1984, until the causative agent was discovered to be a retrovirus (Dr Robert Gallo and Dr Luc Montaginer) and a test was developed (Gallo) to render the blood supply safe. Meanwhile the initial years of what soon was recognized to be an epidemic were spent treating these opportunistic infections in these patients with a rapidly fatal disease once it was diagnosed as AIDS. In retrospect this was the first stage or phase of disease management; it would evolve over the years.
By 1987 the first of the antiviral drugs zidovudine (or AZT) to actually treat the underlying HIV infection was approved by the FDA after studies began at Burroughs Welcome by David Barry, MD and others and at the National Cancer Institute by Samuel Broder, MD and others. Approval came within 25 months of initial studies; a record at the time. Soon came many other drugs and by 1996 there were multiple active agents which when combined produced HAART or Highly Active Anti Retroviral Therapy. This was a distinct turning point because for the first time this lethal disease became a controllable chronic illness where one could survive for decades or possibly more. But if one stopped the drugs once immune function returned toward normal, the disease rapidly recurred in force. So it was suppressed but definitely not cured. Now the key was to get the drugs to the patient, get good compliance and give careful follow-up. Getting the drugs to the patient is no mean feat since they are inherently expensive and many patients are uninsured or underinsured. Taking multiple drugs many times per day is difficult for anyone but harder still if the person is living in poverty or is homeless or is a child with perhaps drug addicted parents. And careful follow-up is difficult for all of the same reasons plus others. And of course the challenges are perhaps even more difficult in many developing countries where the stigma of AIDS is high and the logistical means of getting both the drug and the caregiver to the patient are immense, yet this is just where the vast majority of infected individuals live.
Now a third stage has evolved. With many patients living very long times, caregivers are witnessing a set of new challenges. These are the consequences of long term chronic illness and long term drug treatment. Many patients develop a unique change in body habitus with loss of fat in the face and limbs but an increase in abdominal adipose tissue deep in and around the viscera. The metabolic syndrome is frequent and it is followed by diabetes in many. And late onset cancers of many types are being increasingly recognized. Early onset coronary artery disease is another manifestation of the changing nature of this disease and its treatment. Some believe that the chronic infection leads to chronic inflammation which in turn drives the intimal development of plaque in the coronary arteries and others like the carotids. Early onset osteoporosis is also common with 50 to 67% having osteoporosis or osteopenia well before the expected age. With continued loss of bone mineral density, the risk of fracture at an earlier age with its attendant implications for loss of mobility, hospitalization and death is high.
So for the physician, the change in these evolving stages has been from spending 90% time managing infections to 90% managing the complexities of therapy, its many complications and the long term complications of the chronic infection. Today, the HIV patient on HAART needs regular evaluations for coronary artery disease, metabolic syndrome and osteopenia with life style adjustments and possibly further drug interventions as preventive measures.
There are over 25 licensed antivirals for HIV infection and more are on the way. But whichever ones are used, they must be continued. Stopping has repeatedly proven to be linked to relapse and earlier death.
What will the forth stage be and when will it begin? Let us hope it is the discovery of a vaccine. Only a vaccine will ultimately drive the epidemic down and possibly even contain or eradicate it the way smallpox was or polio and measles could be. The HIV has proven to be very difficult to conquer with a vaccine. Some of the problems include that the initial infection usually goes unnoticed and then it remains latent for many years until the earliest evidence of AIDS appears. Another is the ubiquity of the virus and its ability to undergo sufficient change to escape immune detection. Once the T cell is infected, it is infected for life so a vaccine must be used before, not after, exposure. Of course, there has never been a vaccine produced before to a retrovirus so this in itself is a new hurdle with limited knowledge from former vaccine research to base today’s work upon. The vaccine must block the virus’ ability to enter the cell suggesting an antibody rather than a cellular immune-based vaccine. Dr Robert Gallo, Director of the Institute of Human Virology - believes the target must be the virus envelope – the “fingers” that attach to the T lymphocyte. He and his colleagues recently received over $24 million from the Gates Foundation and the military to further research in this direction.
With about 2,700,000 new infections per year worldwide, a vaccine cannot come too soon. But even when it does, the logistics of getting it to the world’s neediest will be fraught with difficulties. If getting susceptible children immunized against polio and measles has been difficult, HIV will be much more so.
Praise for Dr Schimpff
The craft of science writing requires skills that are arguably the most underestimated and misunderstood in the media world. Dumbing down all too often gets mistaken for clarity. Showmanship frequently masks a poor presentation of scientific issues. Factoids are paraded in lieu of ideas. Answers are marketed at the expense of searching questions. By contrast, Steve Schimpff provides a fine combination of enlightenment and reading satisfaction. As a medical scientist he brings his readers encyclopedic knowledge of his subject. As a teacher and as a medical ambassador to other disciplines he's learned how to explain medical breakthroughs without unnecessary jargon. As an advisor to policymakers he's acquired the knack of cutting directly to the practical effects, showing how advances in medical science affect the big lifestyle and economic questions that concern us all. But Schimpff's greatest strength as a writer is that he's a physician through and through, caring above all for the person. His engaging conversational style, insights and fascinating treasury of cutting-edge information leave both lay readers and medical professionals turning his pages. In his hands the impact of new medical technologies and discoveries becomes an engrossing story about what lies ahead for us in the 21st century: as healthy people, as patients of all ages, as children, as parents, as taxpayers, as both consumers and providers of health services. There can be few greater stories than the adventure of what awaits our minds, bodies, budgets, lifespans and societies as new technologies change our world. Schimpff tells it with passion, vision, sweep, intelligence and an urgency that none of us can ignore.
-- N.J. Slabbert, science writer, co-author of Innovation, The Key to Prosperity: Technology & America's Role in the 21st Century Global Economy (with Aris Melissaratos, director of technology enterprise at the John Hopkins University).