Marketed since late 2014, Keytruda is authorised in the United States, Europe and Switzerland to treat over 20 types of cancer – ranging from cancers of the digestive system and the lungs to those affecting the skin, liver, blood, reproductive organs, kidneys and breast.

Above all, it has enabled the US company Merck Sharp & Dohme (MSD) to generate staggering revenues: $31.7 billion (about CHF 25 billion) in 2025 from this product alone – almost equivalent to the gross domestic product (GDP) of Senegal or Iceland. After 11 years on the market, Keytruda has brought MSD total sales of $162.8 billion, propelling the group to fourth place in the Big Pharma rankings in 2025.

Like Roche’s Herceptin or Perjeta (see our November 2025 episode), Keytruda is a biological drug, made up of monoclonal antibodies. It belongs to the category of immunotherapies – treatments that stimulate the immune system to attack cancer cells. These drugs have undeniably transformed cancer care, making it possible to control the disease and extend the lives of many patients. But this “miracle” treatment comes at an exorbitant price, which leads to restrictions to access and a surge in healthcare costs, as we detail in our investigation. Public Eye shared its analyses with the International Consortium of Investigative Journalists (ICIJ) and its media partners.

Prohibitive prices in Switzerland and abroad

Keytruda is sold at a high price everywhere it is marketed. In Switzerland and the European Union (EU), the real (net) price of the drug, negotiated between MSD and governments, is confidential (see below). The list price for Keytruda – sometimes called reference price – nevertheless gives an indication of the sums involved. And the figures are dizzying.

In Switzerland, Keytruda tops the ranking of the most cost-intensive medicines compiled by health insurer Helsana, which estimates its official cost at CHF 183.4 million for 2024 (the figures for 2025 are not yet available). The official price of the drug – covered by compulsory health insurance since 2015 – is CHF 4,294 for a 200mg pack (standard dose), which is more than the price of an ounce of gold. That amounts to CHF 73,000 per person for an annual treatment according to our calculations, and over CHF 160,000 if other treatments with which it can be combined are included.

In the United States, a 200mg pack of Keytruda costs $11,760 (CHF 9,300 – also a list price), or around $200,000 a year for this treatment alone. As in Switzerland, patients are required to pay a high deductible and substantial co-pays out of pocket in the USA and thereby contribute to large part of the costs – or all of them if they are uninsured. This scenario can lead to significant financial hardship.

As for India, a standard dose costs between CHF 1,750 and CHF 2,000. In a country where most patients pay for medicines themselves, this price is simply prohibitive. Only the wealthiest, and those with sufficient insurance coverage, can afford the treatment.

A proliferation of patents 

MSD is able to maintain a high price for Keytruda because it enjoys commercial exclusivity, relying on its multiple primary and secondary patents (see box).

With the support of the U.S. non-profit organisation I-MAK, we reconstructed the patent landscape pertaining to Keytruda’s active ingredient (pembrolizumab) across several jurisdictions, using public databases. In total, we identified 80 patents granted to MSD in connection with this molecule (see diagram below). A further 66 patent applications were pending in Europe, 55 in the United States and 11 in India. Given how difficult it is to piece together such an overview, the actual number of patents held by MSD for this treatment may be even higher.

This analysis allowed us to assess the consequences of these patents: They grant MSD a potential monopoly lasting at least three decades in Europe, India and the United States on the sale of this highly sought-after active ingredient, thereby restricting access to treatment. This goes well beyond the 20 years provided for under the World Trade Organization’s Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS).

In Switzerland and Europe, thanks to a protection extension granted by national authorities, the exclusivity linked to the primary patent will only expire in 2031 (see chart below). MSD will face competition for the first time in the United States and India in 2028, when Keytruda’s primary patent expires. 

Around a dozen companies are working on biosimilar versions of pembrolizumab (the biological equivalent of generic medicines), including the Swiss firm Sandoz. These manufacturers are seeking to claim a share of a monumental market: sales of Keytruda in the United States account for 60 per cent of its global turnover – representing a market worth nearly $19 billion in 2025.

MSD extends its monopoly

The financial stakes are high, and MSD has already put counter‑measures in place to extend its monopoly for as long as possible. First, by multiplying applications for secondary patents, which account for roughly 95 per cent of its protection titles, with a marked acceleration in filings since 2016 – i.e. after Keytruda was first launched. Then by modifying the mode of administration, switching from intravenous delivery to subcutaneous injection. This tactic called “product hopping”, also used by Roche and other pharmaceutical companies, makes it possible to secure new secondary patents and extend the niche of commercial exclusivity on the market.

According to its own statements, the U.S. company plans to shift 30 per cent to 40 per cent of its target patient base to the subcutaneous version of Keytruda – already available in the United States and the EU, but not yet in Switzerland – by 2028. With new patents covering this mode of administration, it could extend its monopoly until at least 2042.

Finally, the U.S. giant has still the option of initiating legal action against biosimilar manufacturers when the latter are about to bring their products to market. The launch of litigations also delays the market entry of competing biosimilars.

Patent offices overwhelmed

MSD’s secondary patents on pembrolizumab claim a range of modifications to the product but do not cover the active substance, which remains unchanged. Above all, they flood patent offices, extend the duration of the monopoly and delay competition, without any proven therapeutic benefit being required in return.

Known as “evergreening”, the abusive accumulation of secondary patents on therapeutic products is a widespread practice in the industry. In the case of Keytruda, competitors are challenging the novelty of some of these patents. One of them is Halozyme, a company specialising in this field. The biotech firm argues that MSD’s subcutaneous version of Keytruda infringes 15 of its patents and has taken legal action in the United States and Europe. Proceedings are ongoing. Last December, a German court ordered a ban on the marketing of subcutaneous Keytruda pending the outcome of the dispute.

The black box of R&D costs

Why does a drug like Keytruda cost so much? The pharmaceutical industry repeatedly argues that its treatments require heavy investments in research and development (R&D) and that companies must absorb significant risks of failure. These two factors, it claims, justify the high prices charged for medicines once they reach the market.

Testifying before the US Senate health committee in February 2024, MSD’s chairman and chief executive said his company had invested $30 billion in its Keytruda research programme since 2011. This figure cannot be verified, as companies are under no obligation to publish or account for R&D costs on a product-by-product basis. It also raises questions, given that MSD played no role in the discovery or pharmacological conception of the drug, which stemmed largely from publicly funded research. The company acquired the treatment through a corporate acquisition in 2009 and even considered abandoning it before changing course in the face of the success of a rival product with a similar mechanism of action.

To shed light on this issue, we set out to estimate the out-of-pocket R&D investments made by MSD to date for Keytruda (see Box methodology below).

Our estimate of Keytruda’s research and development costs stands at $1.925 billion (CHF 1.52 billion) – equivalent to just 1.2% of the drug’s global sales to date. This is far below the figure cited by MSD’s chief executive. Even when potential failures are taken into account, the total cost of Keytruda’s research and development ($4.79 billion, around CHF 3.8 billion) represents barely 3% of the medicine’s turnover.

Based on the methodology we developed, we then estimated the profit margin generated by MSD on Keytruda sold in Switzerland. This accounts for more than 88 per cent of the official price (see chart below).

This margin shows that pharmaceutical companies are not using high prices to offset substantial R&D costs and hedge risk, but to generate exorbitant profits. Far from being systematically reinvested, these profits call into question the current pricing system, which is supposed to ensure the sustainability of innovation.

More transparency – fewer patents

The findings of our investigation into Keytruda once again highlight the need to act against the excessive pricing of patented medicines. In Switzerland, such drugs are a major driver of rising healthcare costs. The argument put forward by Big Pharma and the White House – that prices are too low in Switzerland and Europe – is clearly contradicted by the substantial margins generated by firms such as MSD.

Patents give drugmakers a monopoly position and prolonged commercial exclusivity. Shielded from competition, they are able to impose their prices worldwide, to the detriment of patients and public health budgets. This must change if we are to safeguard the financial sustainability of a solidarity‑based healthcare system that is now seriously in danger.

It is urgent that authorities in countries hosting major pharma corporations, such as Switzerland, take a stand against the abusive proliferation of secondary patents on medicines. As a member of the European Patent Convention, Switzerland could require more rigorous scrutiny of patent applications in order to limit their number.

Pricing mechanisms must also be reformed, by demanding disclosure of the investments actually made by pharmaceutical companies and the share of public funding involved, rather than relying on ineffective international price comparisons.

In Switzerland, healthcare costs are a growing problem, and an increasing number of people are suffering from soaring insurance premiums. The federal authorities are protecting a system that helps multinationals maximise their profits while preventing the realisation of the right to health for all. This policy also has repercussions beyond Switzerland’s borders, as Swiss drug prices are used as a reference by more than 30 countries, including economically weaker states. By driving prices up, Switzerland is not only impacting its own population, but also millions of patients abroad.