Both Lilly and the Alzheimer’s Association issued statements following the decision saying that the proposed level of coverage would not be enough and that funding the test in only those limited circumstances would hamstring patient care. The last word on the coverage is due this fall when Medicare issues its final decision. Whereas private insurance companies often follow Medicare’s lead on coverage decisions, there is no requirement that the companies mirror its ruling.
A negative result from the PET test is actually more informative than a positive result, says Lawrence Honig, an Alzheimer’s expert at Columbia University Medical Center. No buildup suggests it is unlikely that a patient’s neurological condition is a result of Alzheimer’s. And teasing apart when cognitive impairment is due to Alzheimer’s versus another condition such as frontotemporal dementia is important because drugs used to manage Alzheimer’s could have negative side effects for a patient without the disease, Skovronsky says. Neither Alzheimer’s nor frontotemporal dementia has any existing treatment that stops or slows its progression.
The test from Lilly uses positron emission tomography (PET) to detect collections of amyloid in the brain. To perform the test, a radioactive chemical is injected into the body and then taken up by the brain. The chemical, patented by Lilly, temporarily attaches itself to areas of the brain where there is a concentration of amyloid, and the PET scan picks up that radioactive tag. “Ultimately, what we’re trying to find is like a cholesterol test for the brain,” says Gary Small, director of the University of California, Los Angeles, Longevity Center. “If you go to a doctor and you’re over a certain age, a doctor will test your cholesterol. And if it is high, the doctor will give you a statin and lower your risk of heart attack or stroke.” With Alzheimer’s, however, there is no existing treatment to act as the statin if risk is identified earlier.
Ronald Petersen, director of the Mayo Clinic’s Alzheimer’s Disease Research Center in Rochester, Minn., says that physicians should have such amyloid imaging data at their fingertips because it gives clinicians information that differs from other scans. “In reality, it may not change the treatment plan all that much,” Petersen says. “But I still think it’s important to know if that is what is going on. It may motivate people to engage in lifestyle activities that may influence this process and help people plan for the future—though the timing of that planning may be uncertain.”