Novo Nordisk has responded to growing concerns over reports of sudden vision loss among people taking its GLP-1 medicines, including semaglutide, with new data from randomised clinical trials.

The company has cited a published pooled analysis of placebo-controlled trials of liraglutide and semaglutide involving nearly 97,000 participants and more than 205,000 participant-years of observation. The analysis found no increased incidence of non-arteritic anterior ischaemic optic neuropathy (NAION) among people receiving GLP-1 receptor agonists compared with placebo.

The statement comes after US lawsuits alleged that GLP-1 medicines were responsible for sudden vision loss. Novo says that, taking clinical trials, post-marketing reports and observational evidence together, its assessment of semaglutide's overall benefit-risk profile remains favourable.

But how does this new evidence fit with the regulatory warnings around NAION, and what should Indian patients make of the competing findings?

What Novo Nordisk's data shows

In its statement, Novo Nordisk said semaglutide has accumulated more than 58 million patient-years of exposure through post-marketing use.

The company specifically pointed to a recently published pooled analysis of randomised, placebo-controlled clinical trials involving liraglutide and semaglutide.

The analysis included 96,829 participants. Across the studies, there were 64,917 participants receiving a GLP-1 receptor agonist and 31,912 receiving placebo, with a combined observation period of 205,777 participant-years.

Only three confirmed NAION cases occurred in the GLP-1 receptor agonist group, compared with five cases in the placebo group.

The incidence was approximately 3 cases per 100,000 participant-years among GLP-1 receptor agonist users versus 6 cases per 100,000 participant-years in the placebo group.

Based on these findings, the researchers concluded that the randomised clinical-trial data did not show an increased incidence of NAION with liraglutide or semaglutide.

For Novo Nordisk, this is the central point of its response: despite the recent concern surrounding semaglutide and vision loss, its pooled randomised-trial data did not demonstrate an increased rate of NAION.

Also Read: GLP-1 Drugs Linked To Vision Loss? Novo Nordisk, Eli Lilly Face US Lawsuits

Why the regulatory position is different

The clinical-trial findings need to be considered alongside the regulatory assessment.

In 2025, the European Medicines Agency's safety committee concluded that NAION should be added as a very rare side effect of semaglutide medicines Ozempic, Rybelsus and Wegovy.

The EMA's review considered clinical-trial data, post-marketing reports and observational studies. It estimated that semaglutide could be associated with approximately a two-fold increase in the relative risk of NAION among adults with type 2 diabetes, translating to around one additional case per 10,000 person-years of treatment.

That is an important distinction. The regulatory finding does not mean that a large proportion of people taking semaglutide will develop vision loss. NAION remains classified as very rare. At the same time, the EMA's decision means the possibility cannot simply be dismissed on the basis of the randomised-trial findings.

The UK Medicines and Healthcare products Regulatory Agency has similarly updated safety information for semaglutide medicines and describes NAION as a very rare adverse effect.

Why the studies do not all say the same thing

The difference largely comes down to the type of evidence available.

Randomised controlled trials are designed to compare treatment and placebo groups under controlled conditions. Novo Nordisk's cited analysis therefore provides useful evidence on whether NAION occurred more frequently among trial participants receiving the medicines.

But NAION is extremely uncommon. Only eight confirmed cases were identified across the treatment and placebo groups in the pooled analysis. When an outcome is this rare, even large trials may not produce enough events to definitively establish or exclude a small increase in risk.

Observational studies, meanwhile, have produced mixed findings.

A multinational population-based study involving more than 297,000 people with type 2 diabetes and/or obesity did not find a statistically significant association between semaglutide and NAION.

Other large observational analyses have reported an increased association between GLP-1 receptor agonist use and NAION. However, such studies cannot by themselves establish that the medicine caused the condition.

This is why the current evidence is best described as a very rare safety signal with an uncertain magnitude of risk, rather than proof that semaglutide causes blindness.

What does this mean for Indian diabetes patients?

The issue is particularly relevant in India because of the country's large diabetes burden.

The ICMR-INDIAB study estimated that 101 million Indian adults were living with diabetes, while another 136 million had prediabetes. The study also found a substantial burden of hypertension, generalised obesity and abdominal obesity - conditions that frequently coexist with type 2 diabetes.

This matters because the possible NAION association cannot be viewed independently of a patient's underlying health.

Diabetes itself is an established risk factor for NAION, along with conditions such as hypertension and sleep apnoea. Therefore, an individual patient's baseline risk and medical history remain important when assessing any possible medicine-related risk.

For Indian patients already prescribed semaglutide, the new Novo data should therefore be read as reassuring evidence, but not as evidence that eliminates the safety question altogether.

Patients should not stop semaglutide or change their diabetes treatment solely because of reports of lawsuits. Any decision to start, stop or switch treatment should be taken with the treating doctor, based on glucose control, cardiovascular and kidney health, weight, other medicines and individual risk factors.

At the same time, sudden changes in vision should always receive urgent medical assessment.

Novo Nordisk's overall position

Novo Nordisk said patient safety remains a top priority and that it takes reports of adverse events seriously.

The company said that, considering the totality of evidence from clinical trials, post-marketing reports and observational studies, along with the generally low incidence of NAION, it continues to consider semaglutide's benefit-risk profile favourable.

The company's position is therefore not that reports of NAION should be ignored. Rather, it argues that the available evidence, particularly the pooled randomised-trial data, does not demonstrate an increased incidence of the condition among semaglutide users.

Also Read: Beyond Weight Loss: The Common And Rare Side Effects Of GLP-1 Medications Explained

What patients should take away

For people taking semaglutide in India, the most important point is the difference between a safety signal and established causation.

Novo Nordisk's cited pooled analysis found three NAION cases per 100,000 participant-years in the GLP-1 receptor agonist group compared with six per 100,000 participant-years in the placebo group.

Regulators, however, have identified NAION as a very rare potential adverse effect after considering a broader body of evidence.

These findings are not necessarily mutually exclusive. A very rare adverse effect can be difficult to detect consistently across individual studies, particularly when the number of cases is extremely small.

For now, the evidence supports awareness and pharmacovigilance rather than alarm. Patients should continue prescribed treatment unless their doctor advises otherwise and seek prompt medical attention for sudden or unexplained vision changes.

Novo Nordisk's latest response provides important context to the recent concerns around semaglutide and sudden vision loss. Its pooled analysis of randomised, placebo-controlled trials found no increased incidence of NAION compared with placebo, although the number of confirmed cases was very small.

At the same time, regulators have recognised NAION as a very rare potential adverse effect of semaglutide based on the wider body of available evidence.

For Indian patients, the takeaway is not that there is zero risk, nor that semaglutide causes sudden blindness. The evidence points to a rare and still-evolving safety question, which needs continued monitoring while patients and doctors weigh the medicine's established benefits against individual risks.

Read More: Can GLP-1 Drugs Cause Sudden Blindness? Nonarteritic Anterior Ischemic Optic Neuropathy Explained



Disclaimer: This content including advice provides generic information only. It is in no way a substitute for a qualified medical opinion. Always consult a specialist or your own doctor for more information. NDTV does not claim responsibility for this information.