AILSA CHANG, HOST:
Doctors can now prescribe a controversial new drug to their patients with Alzheimer's disease. But even medical experts are still trying to figure out which patients should get the drug and how to use it safely.
NPR's Jon Hamilton reports from the Alzheimer's Association International Conference in Denver.
JON HAMILTON, BYLINE: The drug, called Aduhelm, received a conditional approval from the Food and Drug Administration in June. The approval came despite conflicting evidence on whether the drug actually slows the progression of Alzheimer's. Since then, some experts have said they won't prescribe Aduhelm at all. But Dr. Alireza Atri of the Banner Sun Health Research Institute in Arizona says that would be unfair to patients and their families.
ALIREZA ATRI: This is an incurable condition, and it's progressive. And I think we need to figure out a way to present that option to them in a way that's safe.
HAMILTON: Usually, doctors look to a drug's label and instructions for guidance on appropriate use and safety. But Atri, who has worked as a consultant to the drug's maker, Biogen, says that's not enough when it comes to Aduhelm.
ATRI: The label left a lot of gaps. So it is important to have, very quickly, some preliminary recommendations regarding how to use this. Because people are using it already.
HAMILTON: Aduhelm presents a special challenge because it must be infused directly into the bloodstream and can cause swelling and bleeding in the brain. So at the Alzheimer's conference, Atri and a panel of scientists offered a set of detailed recommendations. One is to ensure that the drug is given only to patients who are still in the earliest stages of Alzheimer's. Dr. Eric McDade is a neurologist at Washington University in St. Louis who was not involved in the recommendations. He says doctors should say no to patients who appear to be significantly impaired.
ERIC MCDADE: They're probably not safe to be driving. They've given up most of their complex hobbies and social activities outside of the home. This is a patient, for instance, I would say, really, there's no evidence whatsoever that this is going to benefit you.
HAMILTON: McDade also agrees with the recommendation that doctors obtain a brain scan or a test of spinal fluid before giving the drug. He says this is necessary to confirm the presence of the sticky amyloid plaques in the brain that Aduhelm is designed to remove.
MCDADE: Listen. If you are considering using this drug for a patient, it's incumbent upon you to ensure that people have amyloid plaques in their brain.
HAMILTON: Other recommendations include ordering brain scans if patients appear to be experiencing side effects and pausing treatment if the scan shows swelling or bleeding in the brain. Maria Carrillo is chief science officer at the Alzheimer's Association, which supported approval of Aduhelm. She says the recommendations are intended for specialists. Most primary care doctors, she says, lack the training or facilities to offer Aduhelm.
MARIA CARRILLO: We're hopeful that these recommendations can be used by those neurology clinics around the country that do not traditionally participate in clinical trials. So they do not have the experience for setting up this type of clinic.
HAMILTON: But even senior research scientists at the Alzheimer's conference said they still have questions about using Aduhelm. One is how to treat Black and Hispanic patients, who were largely left out of research studies on the drug. Carrillo noted that those studies found that people with a genetic variant called APOE4 are twice as likely to experience side effects from Aduhelm.
CARRILLO: Unfortunately, we don't know enough about the impact of APOE4 on underrepresented populations, in particular, on African American or Latinx backgrounds.
HAMILTON: Several scientists at the conference called for a new study that would focus on these groups.
Jon Hamilton, NPR News, Denver.
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