Fake versions of Keytruda, a blockbuster cancer immunotherapy and among the world’s top-selling prescription drugs by sales, have been detected in multiple markets, including in India-linked supply chains, even as the drug remains under patent protection. The early appearance of counterfeit oncology drugs, well before biosimilars are legally available, raises concerns over gaps in distribution, enforcement, and patient safety.

This comes at a time when India is preparing for a major biosimilar opportunity as patents on high-value biologics begin to expire. Counterfeit products are already in circulation, targeting demand in a market where access remains limited and prices are high.

Developed by Merck & Co., Keytruda is used across cancers including lung cancer, melanoma, and head and neck cancers. With patents expected to expire between 2028 and 2030, Indian companies such as Biocon, Dr. Reddy’s Laboratories, and Cipla are building pipelines to enter the biosimilar segment.

“Keytruda, with global sales of around $25 billion, is set to lose patent protection in 2028, with a biosimilar opportunity of $10–15 billion, implying only partial erosion. However, the impact is expected to be gradual rather than sharp, and the drug is likely to remain a multi-billion-dollar franchise even after biosimilar entry, making it one of the largest yet most resilient assets in the upcoming patent cliff cycle,” said Dr Rashmi Chaturvedi Upadhyay, founder and chief strategy officer at ProVanta Life Tech.

Big market, high cost, limited access

India records 1.4–1.5 million new cancer cases annually, with more than 3 million people living with the disease, according to the Indian Council of Medical Research. The oncology drug market is estimated at $2.5–3 billion and growing at over 12% annually.

Further, the broader oncology opportunity is expanding, with multiple global and domestic companies seeking approvals for new cancer therapies in India. In a Subject Expert Committee (Oncology) meeting held on February 25, proposals involving pembrolizumab and other biologics were reviewed for clinical trials and global submissions, indicating the scale of pipeline activity.

Yet access to advanced therapies remains sharply uneven. A single dose of pembrolizumab in India can cost in the range of Rs 2–4 lakh, depending on the indication and hospital procurement channel, with a full course of treatment running into tens of lakhs. In global markets such as the United States, annual treatment costs can exceed $150,000, or over Rs 1.2 crore.

For a large share of patients in India, where out-of-pocket spending dominates, such therapies remain unaffordable. The government has taken steps to improve affordability. In recent policy measures, customs duty on certain imported cancer drugs has been reduced or waived to lower treatment costs. However, high-value biologics such as Keytruda are not widely covered under such relief in a way that significantly alters patient affordability, and pricing continues to remain a key barrier.

This gap between demand and affordability creates a clear opening. Counterfeit drugs typically enter through informal distribution networks, unauthorised imports, or diversion at the distributor level, particularly in high-value therapies where margins are significant.

Global alerts confirm the scale of the risk. The World Health Organization, in a Medical Product Alert issued in November 2024, warned that falsified Keytruda products “pose a significant risk to public health,” noting that patients may receive “no therapeutic benefit.”

In several cases flagged internationally, counterfeit oncology drugs have entered supply chains outside authorised channels but still reached patients, including in markets with regulatory oversight. Enforcement action has already linked India to the global counterfeit trade. In a case announced on March 5, US authorities said an Indian national had been sentenced to prison for trafficking counterfeit Keytruda that contained no active ingredient and was “wholly ineffective.” Investigators noted the product was “just like water.”

Ozempic shows this starts before patents expire

The same pattern has already been observed with Ozempic, developed by Novo Nordisk. Even before any patent expiry, counterfeit versions of Ozempic were detected across multiple countries. These products were distributed through online platforms, grey markets, and unauthorised sellers, often targeting patients seeking weight-loss treatments where demand surged sharply.

Regulators reported cases where the products contained incorrect ingredients, substituted compounds, or unsafe formulations. In some instances, patients were exposed to serious health risks due to contamination or incorrect dosing.

The comparison with Keytruda is direct. Both drugs are high-value, high-demand therapies with strong clinical outcomes but limited access due to pricing. In both cases, counterfeit versions entered the market while the original product was still under patent protection.

This indicates that counterfeit supply chains are entering early, when demand is high and access remains constrained.

Biosimilar opportunity now faces a supply chain test

India’s drug regulator, the Drugs Controller General of India, has directed state authorities to step up surveillance following global alerts. This includes testing of suspicious batches, monitoring of distributors, and action against unauthorised sales.

Manufacturers have also issued warnings. Takeda Pharmaceutical Company said its oncology drug Adcetris should be procured “only through authorised distribution channels,” highlighting the risks of parallel or unauthorised sourcing.

At the same time, Indian companies are preparing for a large biosimilar opportunity. As patents on drugs such as Keytruda expire, biosimilars are expected to enter at significantly lower prices, typically 30–60% below originator biologics, expanding access to cancer therapies.