Merck's Keytruda Injectable Version: A Paradigm Shift in Oncology Access and Profitability?

Merck's Keytruda, the top-selling oncology drug globally, is poised for a transformative shift with its subcutaneous (SC) formulation, which could redefine patient access and revenue dynamics. As the FDA and European Commission near final regulatory decisions, investors are scrutinizing whether this innovation can offset looming biosimilar threats and patent expiration risks.

Regulatory Momentum: A Gateway to Market Expansion

The SC version of Keytruda has cleared pivotal regulatory hurdles. The European Medicines Agency's Committee for Medicinal Products for Human Use (CHMP) issued a positive opinion in July 2025, recommending approval for all EU indications, including a new indication for resectable locally advanced head and neck cancer Merck Receives Two Positive EU CHMP Opinions for KEYTRUDA^[1]. The U.S. FDA has set a PDUFA date of September 23, 2025, with Merck planning a U.S. launch on October 1, 2025, pending clearance Merck to Launch Subcutaneous Keytruda in the U.S. on October 1^[2]. This formulation reduces administration time from 30 minutes (IV) to just one minute, enabling broader use in outpatient settings and potentially expanding patient adherence Merck lays out subcutaneous Keytruda data amid patent brawl with Halozyme^[3].

However, the commercialization timeline remains contingent on resolving a high-stakes patent dispute with Halozyme Therapeutics. Halozyme alleges Merck's SC formulation infringes 15 of its patents related to hyaluronidase enzymes, seeking an injunction to block launch Halozyme sues Merck over subcutaneous Keytruda^[4]. Merck has countered by challenging seven of these patents via the U.S. Patent and Trademark Office's PTAB, a move that could weaken Halozyme's legal position Merck granted review of Halozyme patent claims by PTAB^[5]. Analysts estimate a 30–40% conversion rate to the SC version within two years of launch, assuming no major delays Merck’s Keytruda SC: Projected Market Impact^[6].

Market Expansion and Revenue Projections: A Double-Edged Sword

Keytruda's dominance in Merck's portfolio is undeniable. In H1 2025, it generated $15.16 billion in sales, accounting for over half of the company's pharmaceutical revenue Can Keytruda Sustain Merck's Growth Through the Rest of 2025?^[7]. Full-year 2025 sales are projected at $32.2 billion, driven by earlier-stage cancer adoption and combination therapies Merck (MRK) Analysis: Keytruda's Future & Pipeline Strategy^[8]. The SC formulation could further extend this growth by improving convenience and reducing healthcare system burdens, potentially delaying biosimilar erosion.

Yet, the long-term outlook is clouded by patent expiration in 2028. The global Keytruda market is forecasted to reach $26.63 billion by 2030 but at a compound annual growth rate (CAGR) of -3.23% from 2025–2030, reflecting biosimilar competition from firms like Celltrion, Amgen, and Samsung Bioepis Keytruda Market to Reach $26.6 Billion by 2030 Amid Patent^[9]. Historical precedents, such as AbbVie's Humira and Roche's Herceptin, suggest Keytruda's sales could plummet by 30–60% within three years post-patent loss Merck’s Keytruda Dependency: A Growth Story With An Expiration Date^[10].

Strategic Mitigation: Innovation and Diversification

Merck's response to these challenges includes aggressive lifecycle management. The SC formulation is part of a broader strategy to delay biosimilar impact, alongside expanded indications (e.g., head and neck cancer) and partnerships like its personalized mRNA vaccine with Moderna Merck & Co. Strategic Growth and Financial Resilience Amid...^[11]. The company has also reallocated $3 billion to R&D, prioritizing next-generation immuno-oncology therapies and cardiometabolic drugs Merck’s $3 Billion Budget Shift: Preparing for Keytruda’s Post-Exclusivity Era^[12].

However, these efforts face headwinds. The SC version's profitability hinges on pricing power, which could be constrained by payers prioritizing cost savings pre-2028. Additionally, Merck's reliance on Keytruda—accounting for 46% of 2024 revenue—leaves it vulnerable to market shocks U.S. Keytruda Market Research Report 2025 | Merck's Keytruda...^[13].

Investment Implications: Balancing Optimism and Caution

For investors, Keytruda SC represents both opportunity and risk. Regulatory approval would unlock immediate revenue growth, with the SC version potentially capturing $5–7 billion annually by 2030 Merck Stock’s Ticking Keytruda Time Bomb^[14]. However, the patent litigation and biosimilar timelines introduce significant uncertainty. A favorable PTAB outcome for Merck could stabilize the SC launch, while a Halozyme injunction might delay commercialization by 6–12 months, eroding market share.

Long-term investors must weigh Merck's R&D pipeline against Keytruda's patent cliff. While the company's diversification efforts are promising, they remain unproven at scale. The SC formulation's success could buy time, but it is not a panacea.