Japan-based pharmaceutical firm Eisai has launched Leqembi (lecanemab) in India following marketing authorisation from the Central Drugs Standard Control Organisation (CDSCO), the country’s drug regulator. It is the first disease-modifying therapy for early-stage Alzheimer’s disease available in India, a treatment that targets the disease’s underlying biology instead of only easing symptoms. The launch comes as India’s dementia burden grows, with 8.8 million elderly Indians living with dementia in 2023, a figure expected to nearly double by 2036.
What Is Alzheimer’s Disease?
Alzheimer’s disease is a progressive brain disorder and the most common cause of dementia, accounting for an estimated 60-70 per cent of all dementia cases worldwide. It is characterised by the gradual destruction of nerve cells, which leads to memory loss, confusion, difficulty in solving problems and, eventually, the inability to carry out daily tasks.
The disease is closely linked to the build-up of abnormal protein deposits in the brain. Amyloid-beta proteins clump together to form sticky plaques between nerve cells, while another protein, tau, forms tangled fibres inside the cells. Over time, these deposits trigger inflammation and damage neurons, shrinking the brain and impairing cognitive function. Age is the strongest known risk factor, and most patients are diagnosed after the age of 65, though early-onset forms of the disease can appear earlier.
Until now, treatment in India, as in most of the world, was limited to symptom management. Drugs such as donepezil and memantine help control memory and thinking symptoms but do not alter the course of the disease. That is why the arrival of lecanemab, a drug that acts on the disease process itself, is considered a landmark in Alzheimer’s care.
What Is Leqembi and How Does It Work?
Lecanemab is a humanised monoclonal antibody, a laboratory-engineered protein designed to attach to a specific target in the body. It is given through a two-weekly intravenous infusion, with the dose calculated on the patient’s body weight.
The drug works by binding to the aggregated, toxic forms of the amyloid-beta protein that gather in the brains of Alzheimer’s patients. Once bound, it helps the body’s immune system clear these plaques while also preventing new ones from forming. This is what makes it a disease-modifying therapy: instead of masking symptoms, it attacks one of the biological hallmarks of the disease, the accumulation of amyloid plaques.
Leqembi is approved only for patients in the early stages of Alzheimer’s disease, covering those with mild cognitive impairment (MCI), a noticeable but modest decline in memory and thinking, and those with mild dementia. Patients must also test positive for amyloid pathology before they can start treatment, using either a cerebrospinal fluid (CSF) biomarker test or a blood-based beta-amyloid test.
Analogy · Treating the Cause, Not the Symptom Expand analogy
Think of Alzheimer’s plaques like garbage piling up inside a house. Older medicines simply closed the curtains so the mess looked neater. Lecanemab is the first treatment that actually calls in a cleanup crew, the immune system, to haul the waste out and keep it from piling up again, slowing the damage the disease does to the brain.
The Clinical Evidence Behind the Approval
The drug’s approval rests on the landmark Clarity AD trial, a global Phase III study that enrolled 1,795 participants with early Alzheimer’s disease. Over 18 months, patients who received lecanemab showed a 27 per cent slower rate of cognitive and functional decline on the trial’s primary clinical scale compared with those on a placebo.
The drug does not reverse damage that has already occurred, nor does it cure Alzheimer’s. Its value lies in slowing the progression of the disease in patients who are diagnosed early, giving them a longer period of preserved memory and independence. Indian patients were not part of the pivotal trial, so Eisai will run a Phase IV post-marketing study in India to gather efficacy and safety data in the local population.
The Risk of Side Effects
Like all powerful therapies, lecanemab carries risks. Its most serious safety concern is ARIA, short for amyloid-related imaging abnormalities, which can show up on brain scans as swelling or small bleeding spots. Most such episodes are mild and resolve on their own, but some can be serious, which is why patients need regular MRI scans during treatment. Other common side effects include headaches and infusion-related reactions.
Because of these risks, lecanemab is not a drug to be prescribed casually. Doctors must confirm the patient’s amyloid status, assess cardiovascular risk factors, and monitor brain scans at scheduled intervals. The United States Food and Drug Administration approved lecanemab in January 2023 and converted it to a traditional approval in July 2023, and it now holds approvals in more than 50 countries and regions, including Japan, China and countries across Europe.
Eisai and the Regulatory Route in India
Eisai is a Japanese pharmaceutical company founded in 1941, with headquarters in Tokyo, and a stated focus on neurology and oncology. It co-developed lecanemab with Biogen, an American biotechnology firm based in Cambridge, Massachusetts, with Eisai leading the drug’s development and commercialisation in most markets.
The Indian approval was granted by the CDSCO, the central authority that regulates the approval of new drugs, the conduct of clinical trials and the quality standards for pharmaceuticals sold in India. It functions under the Ministry of Health and Family Welfare and is headed by the Drugs Controller General of India (DCGI). In India, marketing authorisation for Leqembi is a company-specific approval, not a government subsidy or procurement decision.
In India, Leqembi has a maximum retail price of ₹21,682 per vial, though the actual annual cost varies with the patient’s body weight and the number of infusions required. Given the biweekly dosing schedule, a full year of treatment is expected to cost a substantial amount, well beyond the reach of most Indian families, and the expense of biomarker testing and regular MRI monitoring adds to the burden.
India’s Growing Dementia Burden
The launch has to be seen against the scale of the disease in India. Estimates drawn from the Longitudinal Ageing Study in India (LASI), a large nationwide survey of Indians aged 45 and above conducted jointly by the International Institute for Population Sciences (IIPS), AIIMS and the University of Southern California (USC), put the prevalence of dementia among Indians aged 60 and above at 7.4 per cent in 2023.
That translates into roughly 8.8 million elderly Indians living with dementia, and the figure is projected to nearly double to about 16.9 million by 2036. India’s ageing population is the driving force. The country’s senior citizen population is projected to rise to around 230 million by 2036, roughly 15 per cent of the total population, up from about 104 million in 2011.
Dementia also carries a heavy economic and social cost. Studies estimate the per-person annual household cost of dementia in India at around $571 (about ₹48,000), and much of the care burden falls on family members, most of them women, who provide unpaid care. Late diagnosis, poor awareness and limited specialised services mean most patients are identified only when the disease has already progressed, precisely the stage at which disease-modifying drugs like lecanemab are least effective.
A New Competitive Market for Alzheimer’s Drugs
Eisai is entering a nascent but fast-forming Indian market for disease-modifying Alzheimer’s therapies. About a month before the Leqembi launch, Eli Lilly, an American drugmaker, introduced Lormalzi (donanemab), another anti-amyloid antibody, in India. Lormalzi’s 350 mg vial is priced at ₹91,688, and it is given as a monthly intravenous infusion with a lower frequency of dosing.
The two drugs take different approaches to the same target. Both clear amyloid plaques from the brain, but lecanemab targets the soluble aggregated forms of amyloid-beta, while donanemab homes in on a specific, already-deposited form of the protein. This competition is widely seen as beneficial for patients, giving neurologists more options and potentially exerting downward pressure on prices over time.
| Feature | Leqembi (lecanemab) | Lormalzi (donanemab) |
|---|---|---|
| Company | Eisai | Eli Lilly |
| Class | Humanised monoclonal antibody | Humanised monoclonal antibody |
| Dose frequency | Every two weeks (biweekly) | Once a month |
| India launch | August 2026 | May 2026 |
| Vial price in India | ₹21,682 | ₹91,688 |
The real constraint on both drugs is not the molecule itself but the ecosystem around it. Adoption depends on early diagnosis, access to biomarker testing, the availability of infusion centres and neurologists, and the willingness of patients or insurers to pay. India has no widespread reimbursement for such therapies, and health insurance policies rarely cover them, so out-of-pocket costs will decide who actually receives treatment.
The Way Forward
The arrival of lecanemab in India is a scientific milestone, but it also exposes the gaps in the country’s readiness for Alzheimer’s care. The drug works only when started early, yet most Indian patients are diagnosed late, often years after symptoms first appear. Expanding access will therefore require investment in awareness campaigns, memory clinics, biomarker diagnostic capacity and trained neurologists, especially in smaller cities and rural areas.
There is also a policy dimension. India is yet to finalise a dedicated National Dementia Plan, even as the World Health Organization (WHO) has urged member states to develop such strategies under its Global Action Plan on the Public Health Response to Dementia 2017-2025, which has now been extended to 2031. A coordinated national plan covering risk reduction, early detection, affordable care and caregiver support would complement the availability of new medicines.
Finally, the cost question will shape the drug’s real-world impact. Without reimbursement, price support programmes or domestic manufacturing of comparable therapies, lecanemab will remain accessible only to a narrow segment of patients. As India’s elderly population swells towards 230 million by 2036, the challenge is to ensure that the promise of disease-modifying treatment does not remain confined to those who can afford it.
Key Takeaways
- Leqembi (lecanemab) is India’s first disease-modifying therapy for early Alzheimer’s disease, launched by Japan-based Eisai after CDSCO approval.
- The drug is a humanised monoclonal antibody that clears amyloid-beta plaques from the brain and is given as a biweekly intravenous infusion for patients with mild cognitive impairment and mild dementia.
- In the Clarity AD Phase III trial, lecanemab slowed cognitive and functional decline by 27 per cent over 18 months, and it has been approved in more than 50 countries and regions.
- The drug’s main safety risk is ARIA (amyloid-related imaging abnormalities), which requires regular MRI monitoring during treatment.
- About 8.8 million Indians aged 60 and above lived with dementia in 2023, a figure projected to nearly double to 16.9 million by 2036.
- Leqembi is priced at ₹21,682 per vial in India, and the CDSCO approval was granted with a Phase IV post-marketing study requirement for Indian patients.
