North American Biopharmaceuticals: Moderate Growth in the US Prescription Drug Market, with New Drug Uptake and Biosimilar Substitution Driving Divergence

Overview

This is a chart-based update on the North American biopharmaceutical industry using IQVIA prescription and sales data. The report shows that overall US prescription demand continues to grow moderately and focuses on evaluating the launch pace of several new drugs, the prescription trajectories required to meet 2026 consensus expectations, and competitive changes across immunology drugs, biosimilars, and major therapeutic areas.

Core views

The US pharmaceutical market continues to post low-single-digit growth overall. As of August 14, weekly total prescriptions, or TRx, increased 2.0% year over year, up from 1.4% in the prior week, while growth over the past 12 weeks was 1.4%. As of August 21, weekly TRx growth remained at 2.0% year over year, compared with 2.3% in the year-earlier period. The 4-week and 12-week rolling year-over-year growth rates were 1.8% and 1.4%, respectively, while weekly growth was 0.9% week over week versus 0.2% in the prior week. EUTRx, which adjusts for longer prescription durations, grew 1.8% year over year, below TRx growth over the same period. The report notes that EUTRx accounts for the greater volume associated with 90-day prescriptions and therefore may better approximate actual demand than simple prescription counts when the mix of 30-day and 90-day prescriptions changes. BMY's Cobenfy was approved for schizophrenia on September 26, 2024, and recorded approximately 3,400 prescriptions in the latest week, up from approximately 3,200 in the prior week. Using the launch volumes of Rexulti, Caplyta, and Lybalvi as benchmarks, Morgan Stanley estimates that Cobenfy would need approximately 186K TRx to meet the 2026 consensus estimate of $271mn. Under an assumed net price of approximately $1,450, its prescription volume would need to reach roughly 2 to 5 times that of these comparable drugs at the same point after launch. Therefore, continued growth in current prescriptions does not mean the consensus estimate is already secured; whether the subsequent launch curve can be materially faster than those of previous antipsychotic drugs is critical. GILD's Yeztugo was approved on June 18, 2025, and recorded approximately 1,900 total weekly oral plus injectable TRx in the latest week, compared with approximately 1,700 in the prior week. Of these, injectable prescriptions were approximately 1,160, versus approximately 1,100 in the prior week. The report uses a linear approach and the implied revenue per prescription for the second quarter of 2026 to estimate the weekly injectable prescription trajectory required to meet the third-quarter 2026 consensus estimate of $276mn, while explicitly noting that visibility remains limited at this early stage of the launch. Supportive factors include a continuation rate above 70%, payer coverage reaching 95%, no copay requirement from most payers, and prior authorization or step therapy requirements from only a small number of payers. The PrEP market grew 14% year over year, while Descovy's share remained in the mid-40% range, further increasing the report's confidence in PrEP forecasts beyond 2026. Morgan Stanley estimates 2026 Yeztugo sales of $1,049mn in the US and $1,089mn globally, above Visible Alpha consensus estimates of $999mn in the US and $1,047mn globally; GILD's US guidance is approximately $1.0bn. VRTX's Journavx was approved for acute pain on January 30, 2025, and recorded approximately 29,500 prescriptions in the latest week, up from approximately 28,400 in the prior week. The company noted that IQVIA does not capture hospital prescriptions; in 2025, hospital and retail prescriptions accounted for approximately 45% and 55%, respectively, and the average prescription duration was 10 to 11 days. To meet the 2026 consensus estimate of $228mn, the report estimates that approximately 3.2mn or 2.1mn total prescriptions would be required for an 11-day course under gross-to-net scenarios of 80% or 70%, respectively. Based on sales and prescription data from the two most recent quarters, the actual gross-to-net ratio is estimated at approximately 77%. Morgan Stanley accordingly uses a linear method to calculate the required weekly TRx and separately presents a trajectory that scales actual prescriptions by estimated hospital volume to account for the understatement of demand in retail data. Icotyde, developed by JNJ in partnership with Protagonist, was approved on March 18, 2026, for moderate-to-severe plaque psoriasis and recorded approximately 1,100 prescriptions in the latest week, up from approximately 920 in the prior week. Management stated on its second-quarter 2026 earnings call that more than 18,000 cumulative prescriptions had been written, covering approximately 11,000 patients and approximately 6,000 unique prescribers. The number of prescribers increased further from approximately 4,500 in June; more than 50% of prescribers were advanced practice providers, and approximately 40% were dermatologists. Approximately 65% of new patients were previously treatment-naive, while approximately 20% switched from other oral drugs, and commercial payer coverage had exceeded 50%. The report believes early IQVIA data may not fully reflect actual prescription dynamics. To meet the 2026 US consensus estimate of $255mn, Icotyde would need to grow broadly along the launch trajectories of Otezla or Rinvoq, reaching approximately 31K to 41K TRx in 2026, assuming a monthly list price of $8,285 and gross-to-net discounts ranging from 0% to 25%. In immunology, the report updates its second-quarter 2026 pricing analysis by dividing quarterly sales of Stelara, Tremfya, Skyrizi, Rinvoq, Dupixent, and Cosentyx by the corresponding quarterly IQVIA TRx to assess how changes in utilization from new indications affect revenue per prescription. Product momentum diverged significantly: ABBV's Rinvoq latest-week TRx grew 21% year over year, while its 4-week and 12-week rolling TRx both grew 23%; Skyrizi grew 23% in the latest week, 22% over 4 weeks, and 23% over 12 weeks. Meanwhile, Humira declined 49% across all observed periods, Imbruvica fell 24% in the latest week, and Venclexta grew 22% in the latest week. AMGN's Repatha grew 50% in the latest week, while Otezla declined 11% and Enbrel fell 3%. These data reflect the simultaneous effects of mature-product declines, expansion into new indications, and changes in competitive share. Biosimilar substitution continues to reshape some mature brands. Among latest-week Stelara biosimilar TRx, Biocon's Yesintek held approximately 78% share and AMGN's Wezlana approximately 19%. In the Prolia market, Sandoz's Jubbonti accounted for approximately 25%, Celltrion's Stoboclo approximately 14%, and originator Prolia approximately 54%. The pace of substitution is not determined solely by approval timing: the report believes Remicade biosimilar adoption has been slow because their discounts relative to the originator's net price are insufficient and because payers may lose originator rebates if they switch existing branded patients. The Rituxan market, meanwhile, indicates that “narrow labels” with incomplete indications may have a greater impact on physicians than on payers. Across major therapeutic areas, GLP-1 continues to show substantial prescription volume. Through August 21, Eli Lilly's Mounjaro recorded approximately 855,500 weekly prescriptions and Zepbound approximately 759,700, while its combined diabetes and obesity GLP-1 portfolio totaled approximately 1,732,300. Novo Nordisk's Ozempic recorded approximately 546,500 weekly prescriptions and Wegovy approximately 500,200, while its combined diabetes and obesity GLP-1 portfolio totaled approximately 1,057,000. Year-over-year data also showed that Eli Lilly's total GLP-1 portfolio grew 24%, Mounjaro grew 36%, and Zepbound grew 83%. The report also cautions that diabetes drugs can be used in combination, so a decline in one category's prescription share does not necessarily mean patients have switched directly to another category.

Analysis framework

The report first uses IQVIA weekly TRx, NRx, and extended-unit data to assess total demand in the US pharmaceutical market, then compares the current prescription curves of new drugs with the historical launch trajectories of comparable products. It subsequently works backward from consensus revenue expectations, revenue per prescription, net price, or gross-to-net assumptions to estimate the prescription volumes and growth trajectories required to meet expectations. For mature products, it analyzes competitive changes using prescription share, year-over-year growth, sales, and biosimilar penetration.

Methodology notes

• Industry/Sector Analysis FrameworkVolume-price decomposition

  Analysis of sales, prescription volume, and revenue per prescription

  The report estimates revenue per prescription by dividing quarterly sales by quarterly IQVIA TRx and combines this with prescription growth to determine whether revenue changes stem from utilization, indication mix, or pricing.

• Event-Driven Strategies and Behavioral FinanceEvent-driven analysis

  Tracking post-approval prescription uptake for new drugs

  Starting with the event of drug approval, the report monitors weekly prescriptions, payer coverage, and prescriber expansion to assess commercialization progress.

• (Method Outside the Vocabulary)

  Historical drug-launch analogies and linear back-solving of prescription trajectories

  The report compares new drugs with the early launch curves of products for similar indications and works backward from consensus revenue expectations to estimate the weekly prescription volumes required in the future.

• Industry/Sector Analysis FrameworkSubstitution Effect Analysis

  Biosimilar share substitution for originator brands

  The report tracks the prescription or sales shares of originator drugs and individual biosimilars and explains adoption rates using net price differences, rebates, and completeness of indication labels.

Asset mapping & comparison

Structured mapping from thesis to named assets (strengths, weaknesses, peers, risks).

• Bristol Myers Squibb (BMY)

  Cobenfy is a key new drug tracked in the report, and its prescription curve is used to assess the 2026 revenue expectation.

  Strengths

  Latest-week prescriptions increased from approximately 3,200 to approximately 3,400.

  Weaknesses

  The prescription volume required to meet the 2026 consensus estimate of $271mn is materially higher than historical antipsychotic launch analogies.

  Comparison

  The report estimates that Cobenfy needs to reach approximately 2 to 5 times the launch volume of Rexulti, Caplyta, and Lybalvi at the same point after launch.

  Risks

  If prescription growth fails to materially outpace comparable drugs, the approximately 186K TRx implied by the 2026 consensus estimate may be difficult to achieve.

• Gilead (GILD)

  Yeztugo is a new PrEP drug tracked by the report, with prescriptions, continuation rates, and payer coverage used to assess launch progress.

  Strengths

  The continuation rate exceeds 70%, payer coverage has reached 95%, and the PrEP market grew 14% year over year.

  Weaknesses

  The report explicitly states that visibility remains limited at this early stage of the launch.

  Comparison

  Morgan Stanley's 2026 estimate is above Visible Alpha consensus expectations, and the launch trajectory is compared with Descovy and Apretude.

  Risks

  Meeting the third-quarter 2026 consensus estimate of $276mn depends on weekly injectable prescriptions continuing to grow along the trajectory inferred by the report.

• Vertex (VRTX)

  Journavx prescription data are used to estimate the scale required for the acute-pain drug to meet 2026 revenue expectations.

  Strengths

  Latest-week prescriptions were approximately 29,500, up from approximately 28,400 in the prior week.

  Weaknesses

  IQVIA does not capture hospital prescriptions, which accounted for approximately 45% of prescriptions in 2025.

  Comparison

  The report works backward to estimate required total prescriptions under gross-to-net scenarios ranging from 70% to 80%.

  Risks

  Revenue realization is sensitive to hospital prescription estimates, the assumed 11-day treatment duration, and the actual gross-to-net ratio.

• Johnson & Johnson (JNJ)

  Icotyde's launch pace and Stelara biosimilar substitution both affect the report's assessment of the company's immunology business.

  Strengths

  Icotyde has reached approximately 11,000 patients and approximately 6,000 prescribers cumulatively, with commercial payer coverage exceeding 50%.

  Weaknesses

  Stelara faces rapidly increasing prescription share from biosimilars.

  Comparison

  The trajectory required for Icotyde to meet consensus expectations is compared with the launch trajectories of Otezla and Rinvoq.

  Risks

  Early IQVIA data may understate actual prescriptions, but Icotyde still needs to reach approximately 31K to 41K TRx in 2026.

• AbbVie (ABBV)

  The company simultaneously reflects growth in innovative immunology products and declines in mature brands.

  Strengths

  Rinvoq's latest-week TRx grew 21% year over year, Skyrizi grew 23%, and Venclexta grew 22%.

  Weaknesses

  Humira declined 49% year over year, while Imbruvica fell 24% in the latest week.

  Comparison

  New prescription trends for Skyrizi and Tremfya are tracked side by side.

  Risks

  Mature-brand declines and biosimilar substitution may offset some growth from new products.

• Amgen (AMGN)

  The report tracks prescriptions and share performance for Repatha, Otezla, Enbrel, and the company's biosimilars.

  Strengths

  Repatha's latest-week TRx grew 50% year over year; Wezlana captured approximately 19% of Stelara biosimilar share.

  Weaknesses

  Otezla's latest-week TRx declined 11% year over year, while Enbrel fell 3%.

  Comparison

  In the Prolia market, the originator held approximately 54% share, while Jubbonti and Stoboclo held approximately 25% and 14%, respectively.

  Risks

  Faster Prolia biosimilar penetration may continue to reduce the originator brand's share.

• Eli Lilly (LLY)

  The GLP-1 portfolio is one of the therapeutic areas with the most prominent prescription volume and growth in the report.

  Strengths

  Through August 21, Mounjaro and Zepbound recorded approximately 855,500 and 759,700 weekly prescriptions, respectively, while the total GLP-1 portfolio grew 24% year over year.

  Weaknesses

  Trulicity declined 25% year over year, while Basaglar fell 46%.

  Comparison

  Eli Lilly's combined diabetes and obesity GLP-1 portfolio recorded approximately 1,732,300 weekly prescriptions, compared with approximately 1,057,000 for Novo Nordisk's portfolio.

  Risks

  The report cautions that diabetes drugs can be used in combination, so changes in prescription share cannot be interpreted simply as direct switching between brands.

Key data

• US Market Weekly TRx YoY+2.0%Through August 21; +2.3% in the year-earlier period
• US Market 4-Week Rolling TRx YoY+1.8%Through August 21
• US Market 12-Week Rolling TRx YoY+1.4%Through August 21
• Weekly TRx WoW+0.9%+0.2% in the prior week
• Weekly EUTRx YoY+1.8%Below TRx year-over-year growth over the same period
• Cobenfy Weekly Prescriptions~3,400Approximately 3,200 in the prior week
• Cobenfy 2026 Consensus Estimate$271mnThe report estimates approximately 186K TRx would be required, assuming a net price of approximately $1,450
• Yeztugo Total Weekly TRx~1,900Approximately 1,700 in the prior week; approximately 1,160 injectable prescriptions
• Yeztugo Payer Coverage95%Continuation rate above 70%
• Morgan Stanley's 2026 Yeztugo EstimateUS $1,049mn; Global $1,089mnVisible Alpha consensus estimates are US $999mn and global $1,047mn
• Journavx Weekly Prescriptions~29,500Approximately 28,400 in the prior week; excludes hospital prescriptions
• Journavx 2026 Consensus Estimate$228mnThe report estimates a gross-to-net ratio of approximately 77%
• Icotyde Weekly Prescriptions~1,100Approximately 920 in the prior week
• Icotyde 2026 US Consensus Estimate$255mnThe report estimates that 31K to 41K TRx would be required, assuming a monthly list price of $8,285
• Stelara Biosimilar ShareYesintek ~78%; Wezlana ~19%Latest-week TRx share
• Prolia Market ShareOriginator ~54%; Jubbonti ~25%; Stoboclo ~14%Latest-week TRx share
• Eli Lilly GLP-1 Portfolio Weekly Prescriptions1,732,300Through August 21, covering diabetes and obesity indications
• Novo Nordisk GLP-1 Portfolio Weekly Prescriptions1,057,000Through August 21, covering diabetes and obesity indications

Impact & implications

The report believes overall demand in the US prescription market continues to grow, but company-level performance depends more heavily on new drug launch pace, payer access, prescription data coverage, and biosimilar substitution. Yeztugo is supported by payer coverage and PrEP market expansion, while Cobenfy, Journavx, and Icotyde still require specific prescription ramp trajectories to meet 2026 consensus expectations. Mature immunology drugs, meanwhile, show a combination of growth in innovative products and substitution pressure on originator brands.

Risks

• IQVIA's prescription and sales databases use different methodologies. Sales reflect list prices and exclude rebates and discounts, so they cannot be viewed directly as net revenue.
• Hospital prescriptions, mail-channel restrictions, and vendor contract limitations may result in incomplete prescription or sales data for certain products.
• The required prescription trajectories for new drugs are estimated using linear projections, and the report explicitly notes that visibility into some early-stage launches remains limited.
• The pace of biosimilar adoption is affected by net price discounts, originator-drug rebates, and the completeness of indication labels.

What to watch

• Continue tracking whether weekly TRx for Cobenfy, Yeztugo, Journavx, and Icotyde can grow along the trajectories required to meet 2026 consensus expectations.
• Monitor Yeztugo's injectable prescriptions, continuation rate, payer coverage, and PrEP market growth.
• Track Icotyde's prescribers, new patients, commercial payer coverage, and differences between IQVIA data and management disclosures.
• Monitor Stelara and Prolia biosimilar shares, as well as changes in prescriptions and revenue per prescription for immunology products such as Skyrizi, Rinvoq, and Tremfya.
• Continue tracking absolute prescription volumes, year-over-year growth, and category shares for major GLP-1 products.