Responding to the ‘feverish media coverage heralding a new era of disease modifying treatments’, described by the BBC as a ‘momentous breakthrough’ a scathing editorial in the British Medical Journal says: “Hyperbolic rhetoric gives patients and their families false hope, which clinicians must address, and pre-empts regulatory decision making.”
“Such treatment has been long hoped for,” they say. “However, the null effects on cognition of other anti-amyloid agents, the tiny effect on cognition reported for [the new drug] lecanemab and concerns about safety mean that perspective is needed.”
“The prevailing narrative is that this trial “succeeded” where others have “failed.” In reality, lecanemab, like other anti-amyloid agents, successfully cleared amyloid from the brain. This clearance had no discernible effect on cognition in some trials, a very small and non- significant effect in other trials, and a very small significant effect in the latest trial. The overall trial evidence tells us that successful amyloid clearance in adults with early Alzheimer’s disease has either no effect or a tiny effect on cognitive decline.”
“Previous attempts to quantify the minimum clinically important difference in the trial’s primary outcome measure—the Clinical Dementia Rating (CDR) sum of boxes score (range 0-18 —suggested that minimum changes of 0.98 in mild cognitive impairment and 1.63 in mild Alzheimer’s disease are meaningful. After 18 months of treatment with lecanemab, differences of 0.35 and 0.62 for those with mild cognitive impairment and mild Alzheimer’s disease, respectively, fell well short, representing only around a third of what a minimum clinically important difference might look like.”
Both B vitamins and omega-3 have achieved a clinically significant reduction in the CDR by these criteria, as well as improving other measures of cognition, and in reducing the rate of brain shrinkage. The rate of brain shrinkage reduction of this kind of drug is 2% compared to up to 73% less shrinkage with B vitamins in those with sufficient omega-3. Yet both UK, US and EU government and medical agencies have repeatedly declined funding a definitive trial of both B vitamins and omega-3.
The BMJ editorial expresses serious concerns about safety of this class of drug, which is really an antibody injection. “As with other anti-amyloid agents, lecanemab comes with substantial safety concerns. During the trial, 12.6% of participants treated with lecanemab developed brain oedema (swelling), 22% of whom were symptomatic. A further 17.3% experienced brain haemorrhage; and 6.9% experienced adverse events severe enough to discontinue the trial.” That means that 30% of drug trial participants had a serious adverse effect.
While the number of deaths in the main trial were comparable between the drug and placebo group “more information is needed about two deaths reported during the trial’s open label extension. Both participants had brain haemorrhage, possibly associated with taking lecanemab alongside anticoagulants or thrombolysis.”
They say that “Lecanemab if licensed is likely to cost tens of thousands of pounds a year for each patient. In addition, health systems would need to provide PET scans or lumbar puncture to determine eligibility, fortnightly infusions of the drug indefinitely, and repeated MRI [scans] to monitor for adverse events, all of which is far beyond the capacity of most countries, even those with well-resourced healthcare systems.” B vitamins and omega-3 have no side-effects, other than knock-on health improvements, and cost pennies, not thousands of pounds.
Pressure for approval and clinical use, the BMJ says, is likely to be fierce. “Viewed objectively, however, lecanemab is not the hoped for “game changer.” Rather, it is further evidence that anti-amyloid therapies do not produce clinically meaningful benefits for people with Alzheimer’s disease. Weighed against the scale and severity of adverse events and substantial practical barriers to widespread use, lecanemab is unlikely to represent a favourable risk-benefit balance for patients or value for money for health systems.”
The fully referenced BMJ editorial can be viewed here.
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