nos-trum. pronunciation: \nos'-trum\. noun. Etymology: Latin, neuter of noster our, ours.
1. a medicine of secret composition recommended by its preparer but usually without scientific proof of its effectiveness.
2. a usually questionable remedy or scheme.
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Tuesday, March 1, 2011

Ethics... And Evaluating New Treatments For Serious Diseases

A new approach to gene therapy for AIDS is promising, but...

We've known for decades that a few people are resistant to HIV--on the order of 1 in 100.  They can be shown to be infected, but don't get sick (so far) and don't need to take medicine.

There's a receptor (CCR5) on the surface of the immune cells that HIV attaches to, in order to infect the cell.   These rare individuals seem to lack that receptor, and the gene that produces it.  No receptor, no virus attachment, no infection of the cell....get on with your life.

Researchers have discovered a way to take immune cells from someone who has the disease and snip out the genetic code repsonsible for this receptor, then grow a whole bunch of these cells and give them back to the patient.  For a decent summary of the research go here (Assoc Press, Feb 28).

The modified cells appear to survive when put back in the host.  The hypothesis is that they are resistant to infection with the virus and can continue to do their job in the immune system.

It's exciting, but reading the news article, I asked myself why we have this receptor, and what does it mean if we don't have it?  We don't know.  The reseachers realize this, and know that before we go modifying every patient's cells, we need to understand the function of this gene.

The few people who have been treated so far with modified cells have shown some improvement, but it's not a cure.

Ethical question for the day:   How do you balance our limited knowledge of the safety of a new treatment against the harmful effects of not giving the treatment?  Assume that three years from now, we can't find any reason to justify not removing this CCR5 receptor from the immune cells of patients who are ill with HIV, and on several medicines a day to keep the disease at bay.  What if you could read the future and knew that it would take us 20 years to find out that CCR5 becomes essential to the immune system later in life?  Treatment with treated cells would help now, but create a new problem later.  If long-term studies show that people treated with the modified cells are harmed by the treatment, even though they benefited in the short run, can they sue?

Far-f;etched?  A little, but this happened with the early hearrt valves.  Until the first artificial valves were invented most people died of their leaky valves.  After getting a new lease on life for 20-30 years, the valves began to crack from the constant pounding they took from pulsating blood flow.

The patients sued:  defective product.

I don't have a good answer to questions like these.  I suspect that all new treatments and devices are vulnerable.  Political pressure will be put on the FDA to approve quickly, and then they will be criticized later if long-term studies show problems that could have been avoided if there had been more research.

We saw this last week, when it was reported that medical devices approved quickly were recalled more often.  I doubt that this occurred because the devices were shoddy workmanship.  More likely the devices needed more time to be studied before approval.  This is the Monday Morning Quarterback phenomenon:  "We shoulda known..."

For something like HIV, any investigational therapy will undergo the same push to get it out quickly.  Particularly if the media hails it as a "breakthrough" even while the therapy is still in the developmental stages.

How many times have we heard about breakthroughs?  Some recent research suggests that most of these new and exciting ideas never see the light of day because the research was faulty or we find a problem ("the operation was a success but the patient died").

Experience suggests that almost all "breakthroughs"  never break through.

Doc D

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