New Drug Launch Trajectories and Biosimilar Penetration: US Biopharma Investment Insights from IQVIA Prescription Data

Key Conclusions

IQVIA weekly prescription data reveals that overall growth in the U.S. pharmaceutical market is slowing (latest weekly YoY -0.2%, rolling 12-week YoY +0.7%). However, there is a pervasive gap between early launch prescription trajectories and consensus expectations for new drugs, while the rate of biosimilar erosion of brand-name drugs shows significant therapeutic area variation. The 2026 consensus revenue forecasts for new drugs such as Cobenfy, Yeztugo, Journavx, and Icotyde face high uncertainty in achieving prescription volume targets — Cobenfy would need to reach 2-5 times the prescription volume of comparable antipsychotics; Journavx requires total prescriptions of 1.2–2.0 million due to approximately 70% GTN; and although Yeztugo has achieved 85% commercial coverage, the PrEP market growth rate is variable. On biosimilars, three years after Humira's biosimilar launch, the originator still holds 67% prescription share, while Stelara biosimilars captured 31% share within six months of their concentrated launch in early 2025, illustrating the profound impact of payer switching dynamics and brand pricing strategies on the pace of profit erosion.

Early Launch Performance: Consensus Expectations Face Real-World Challenges

Market optimism for new drugs often underestimates the barriers to achieving prescription volume targets. Cobenfy (BMY, approved September 2024) has the latest weekly prescriptions of approximately 3,010. The 2026 consensus revenue of $296 million would require approximately 196,000 total prescriptions (assuming a net price of $1,450), which would require 2-5 times the prescription volume of comparable products like Rexulti/Caplyta/Lybalvi. As of week 30, Cobenfy's prescription trajectory is well below this multiple benchmark; without a significant acceleration in prescription growth, revenue realization risk is tilted to the downside.

Yeztugo (GILD, approved June 2025) injectable has achieved 85% commercial coverage, with most payers not requiring copays or only having minimal prior authorization/step edits — this coverage progress exceeded expectations. Latest weekly total prescriptions are approximately 1,660 (oral + injectable), with injectable at about 940. The 2026 VA consensus for U.S. revenue is $209 million, versus GILD management guidance of approximately $1 billion — a nearly 5x gap. IQVIA data supports GILD's guidance as more realistic — the PrEP market is growing 14% YoY, with Descovy share >45%; Yeztugo, as a daily oral PrEP, offers convenience advantages, but absolute prescription volume is still in early ramp-up and requires ongoing tracking.

Journavx (VRTX, approved January 2025) latest weekly prescriptions are approximately 19,200 (based on 12-day course). The 2026 consensus of $237 million requires total prescriptions of 1.2 million (50% GTN) to 2.0 million (70% GTN). GTN stabilized at approximately 70% in 2Q