How Merck uses patents to help maintain Keytruda’s exorbitant price

ICIJ says Merck has 50 active U.S. Keytruda patents that could extend market exclusivity through at least 2042, roughly 14 years beyond the core patents’ 2028 expiry. The report highlights an evergreening strategy using hundreds of additional patent filings, including nine active secondary patents on Keytruda combinations, which could delay biosimilar competition and preserve pricing power.

Analysis

The market should treat this less as a binary patent-expiry story and more as an option on duration: the more layered the IP stack, the higher the probability that Keytruda’s revenue decay is delayed, smoothed, or carved into a slower glide path rather than a cliff. That matters because MRK is still priced by many investors as a late-cycle mega-cap pharma with a visible patent event; if exclusivity meaningfully extends, the valuation gap versus other large-cap healthcare names can persist longer than consensus expects.

The second-order impact is on competitors and capital allocation across oncology. A longer Keytruda runway raises the hurdle rate for biosimilar and next-wave checkpoint inhibitor programs, particularly for smaller biotech companies that would need to fund expensive litigation just to access a crowded market window. It also favors Merck’s manufacturing and combination-therapy ecosystem: even if a direct biosimilar launch is delayed only 12-24 months, that is enough time for payer contracting, guideline entrenchment, and combo-trial positioning to lock in share.

The key risk is that the article itself likely underweights legal fragility: not all active patents translate into enforceable moat, and generic/biosimilar challengers can attack validity in parallel, shortening the real-world exclusivity window. But the catalyst path is asymmetric—every additional favorable patent ruling or settlement pushes the market’s feared cliff farther out, while the downside only gets priced quickly if a credible challenger wins a major case or the FDA pathway for biosimilars becomes cleaner than expected over the next 12-24 months.

Contrarian view: the market may already be mentally braced for a 2028 patent cliff, so any credible evidence of extension is less about absolute earnings upside and more about preventing multiple compression. In that sense the trade is not simply ‘long MRK on better patents,’ but ‘short the names and baskets most exposed to an assumed 2028 erosion schedule.’

Key Decisions for Investors

• Long MRK vs short a diversified large-cap pharma basket over the next 6-12 months; the risk/reward favors MRK if the market has over-discounted the patent cliff and is forced to extend peak-sales assumptions.
• Buy MRK 12-18 month call spreads into weakness, targeting a re-rating if investors begin to model a slower post-2028 decay curve; defined risk is preferable because the legal timeline is noisy.
• Short a small-cap oncology biotech basket or equal-weight biosimilar basket as a relative-value hedge; these names are most vulnerable to delayed market-entry economics and higher litigation costs.
• If MRK rallies sharply on IP headlines, take partial profits rather than chase—the better entry is on pullbacks after the first move, since the true catalyst path is measured in quarters, not days.