The Search for Extraterrestrial Intelligence has always looked for an anomaly in the persistent cosmic background chatter—a change perhaps in the intensity of a signal that can be taken as a sign that a transmission might be a message to us earthlings from other intelligent beings.

Each year, medical researchers who gather at the Alzheimer's Association International Conference search for something similar as they weigh reports of the complex biology of the human brain for some sign that a drug might actually change the relentless course of the disease. Unlike many other major diseases that afflict millions of people, Alzheimer's lacks a medicine that can send a patient into remission or maybe even effect a cure.

On Tuesday, in Vancouver, the pharmaceutical company Baxter International reported to conference attendees on a weak but enticing signal, a drug that, if it works in larger clinical trials now under way, might actually stabilize patients and stop disease progression. Gammagard, or intravenous immunoglobulin, a soup of antibodies extracted from blood donors and already approved for some immune disorders, halted for three years any decline in cognition and in the ability to perform everyday tasks for four patients who received the highest dose.

Four patients? True, it may be nothing. Too few patients, for sure, to make any predictions about whether, as so often in the past, the drug may falter and go by the wayside as it makes its way through the clinical trials pipeline . But the results still intrigued some in the research community who are normally circumspect about early reports. ‘‘It’s tantalizing. If you were to pick out four people with Alzheimer’s disease, the likelihood that they would perform the same on standardized tests three years later is very, very tiny,’’ William Thies, the scientific director for the Alzheimer's Association, told the Associated Press.

Results from late-stage clinical trials next year will show whether these four were patients who just happened to have plateaued for a while during their inevitable decline. "While the initial findings are encouraging, they are extremely preliminary," says Eric Reiman, executive director at the Banner Alzheimer's Institute in Phoenix. Until the results of the larger double-blind Phase 3 results demonstrate a significant benefit, intravenous immunoglobulin's role in the treatment of AD is unproven."

If later trials succeed, the results would give credence to the idea that Alzheimer's usual suspect—a toxic peptide called amyloid-beta—is, in fact, the major heavy in the neurodegeneration for the leading cause of dementia—a hypothesis called into question by halting progress in drug development. Gammagard may, in fact, target various forms of the peptide.

The trials might also dispel growing pessimism about whether the disease can be treated after memory has already started to fade, doubts that have pushed researchers toward trying to diagnose and then treat even before the first symptom appears.

A positive Phase III trial next year will mean, though, that the real work lies ahead. The drug, not covered by insurers, is already used off-label to treat Alzheimer's by some rich patients who can afford to shell out $50,000 a year from their own pockets. If one day insurers were to cover Gammagard, not enough supply would exist for the donor-based drug—and shortages would make life difficult for patients already using it for immune conditions. A promising outcome for the drug trial may serve more as a proof of principle for developing more practical pharmaceuticals than a confirmation that Gammagard has emerged as a drug of choice for Alzheimer's.

So Gammagard could be a weak beeping sound, however faint, that points in the right direction. Alternatively, it could be the biological equivalent of the WOW! signal, received by SETI in 1977 as a possible message from extraterrestrials, only to be later dismissed. Stay tuned. For a major disease that has less going for it than other heavyweights, including heart disease, cancer and even some neurological diseases, a treatment that could slow patients' inexorable decline would mark a medical milestone.

Source: National Institutes of Health/Wikimedia Commons