Why Lecanemab, the New 'Breakthrough' Drug for Alzheimer’s, Is Different?

The drug breaks down beta-amyloid proteins in people who are still in the early stages of the disease.

Alzheimer’s, which is the most common type of dementia, is a disease that leads to cognitive impairment in patients, harms their brain’s ability to reason or perform basic activities, and leads to a decline in their memory.

(Photo: The Quint)

(This story was originally published on 30 September 2022. It is being republished from The Quint's archive as the United States Food and Drug Administration has unanimously endorsed Lecanemab for Alzheimer's treatment.)

Being hailed as a “breakthrough” and a “historic moment” in the Science world is Eisai and Biogen’s new drug lecanemab, which reportedly “slows the pace of the brain’s decline” in people suffering from Alzheimer’s disease.

The drug was given to 1,795 Alzheimer’s patients every two weeks during an 18-week trial, and it was found that their “cognitive decline” had slowed by 27 percent – essentially, having an effect on people who are still in the early stages of the disease.

The drug, an antibody, attacks the beta amyloid, which is a toxic protein that forms plaques in the brain, and helps the immune system clear it off.

The Upside

According to The Guardian, “On a 14-point scale used to assess Alzheimer’s progression, patients on the drug scored 0.45 higher than those on the placebo treatment, with an Alzheimer’s patient being expected to decline by about 1 point a year."

It’s also the first time in over 20 years that any drug has shown promise, and the first time ever that there’s the probability of the disease “slowing down” and declining the pace of brain damage in patients.

University College London’s professor John Hardy told the BBC that the results “look like the first truly positive mechanistic trial results in Alzheimer's disease. This is clearly not a magic bullet but it looks like a definite 'end of the beginning'."

UCL's professor of old-age psychiatry, Rob Howard, also told BBC, "This is an unambiguously statistically positive result and represents something of an historic moment, when we see the first convincing modification of Alzheimer's disease.

The ‘Ifs And Buts’

Not everything about the new drug is rosy though. The drug does have side effects on the patients – brain swelling, small bleedings, and headaches, reported BBC.

But Managed Healthcare Executive said in an article that only 21.3 percent of the people who took lecanemab experienced these side effects. Besides, 9.3 percent of the people in the placebo group also experienced brain swelling and bleeding.

It’s also still not clear if amyloid is the only toxic protein that causes dementia, since there have been multiple failed drug trials over the years. What this essentially means is that dementia being caused by amyloid is still a hypothesis, and there's no guarantee that a drug that breaks down amyloid in the patients might help them recover from dementia in the long run.

Additionally, lecanemab does not “slow down” any other form of dementia, barring Alzheimer’s.

Though the drug reportedly proves to slow the pace of the disease in early-stage patients, there’s no data about its effects on patients who have already reached the severe stages, or even on people who have still not been diagnosed with Alzheimer’s but are high-risk.

According to Endpoints News, the drug might cost anywhere between $9,249-$35,605 annually. According to Alzheimer’s Association, there are currently 6.5 million American citizens aged 65 and above who suffer from the disease. This, then, is a matter of concern for United States citizens who are wary that the cost of this drug might have to be borne by Medicare, which is the nation’s federal health insurance programme.

Is the Drug Available for Use?

The complete research on the drug hasn’t been made public yet, but Eisai and Biogen will start the process to get the drug approved in the United States, Japan, and Europe.

However, if and when the drug is approved, it also remains to be seen how countries decide to fund it, since the drug will be required to be injected into patients every two weeks.

Didn’t Biogen Also Come Up With a Drug for Alzheimer’s Last Year?

On 7 June last year, the US Food and Drug Administration had given “accelerated approval” to Biogen’s new drug called aducanumab (marketed as aduhelm), which also claimed to slow down the pace of Alzheimer’s in patients who were still in the early stages of the disease.

However, The Washington Post had reported at the time that some members of the FDA’s advisory committee submitted their resignation after the recommendation against the drug was neglected.

The members had been advocating against the drug since there was no conclusive evidence that it worked. They claimed that the drug had been given approval even though there was no proof that it was better than or had an advantage over any of the existing methods of treatment.

Apparently, out of the two trials for the drug, one had shown positive results, while the other showed negative results.

The scientists were also divided on the approval of the drug since it would have cost patients (and/or their families) nearly $56,000 a year to get the drug injected on a monthly basis, even though there was no surety that it would work. However, Biogen had to cut the cost of the drug into half only six months after this.

Aduhelm had only been tested in a white population, unlike lecanemab, which violated the diversity criteria too.

(With inputs from BBC, The Guardian, Reuters, and Endpoints News.)