Keytruda’s Q1 Strength Masks Underlying Headwinds

What happened

Keytruda delivered $8B in Q1 sales, reinforcing its dominance and supporting near-term revenue. However, this performance does not alter the fundamental challenge: Keytruda represents 49% of total sales and faces a two-step decline from biosimilars (potentially Dec 2028) and IRA pricing (effective Jan 2029). Meanwhile, Gardasil shipments to China remain paused with no restart visibility, and a $2.5B headwind from generics/IRA pressures the 2026 bridge. The company’s aggressive M&A (Verona, Cidara, Terns) and restructuring aim to build post-Keytruda pillars, but these moves have yet to deliver material revenue proof. The stock’s current price ~$119 reflects a holding pattern, with rerating dependent on concrete evidence that new launches and cost savings offset the looming erosion.

Implication

The Q1 Keytruda beat provides a near-term buffer, but the structural overhang remains. The 6-12 month window hinges on whether management can contain the ~$2.5B headwind and show that new assets (Winrevair, Capvaxive) are gaining traction. Without that, the bear case of ~$95 becomes more plausible.

Thesis delta

The recent article reinforces Keytruda’s near-term strength, but does not change the core thesis that Merck’s earnings power remains concentrated and vulnerable post-2028. The deep value report already accounted for Keytruda’s resilience; the Q1 data simply confirms it. The key uncertainty—Gardasil China restart—remains unresolved, so the WAIT rating is unchanged.