Merck and Co., known as MSD outside the United States and Canada, sits at a defining strategic moment across its respiratory and pulmonary oncology portfolio. Keytruda, the PD-1 inhibitor that became the world's best-selling oncology drug with global revenues exceeding $29 billion in 2024, faces a core US patent expiry in 2028, creating the most consequential intellectual property event in the history of oncology pharmacology.[2] At the same time, the company has entered the established RSV prophylaxis market with the June 2025 FDA approval of Enflonsia (clesrovimab), competing directly against Beyfortus (nirsevimab) from Sanofi and AstraZeneca. [4]
For pharma competitive intelligence teams across respiratory, pulmonary oncology, and infectious disease programmes, Merck's decisions in 2026 create signals that affect protocol endpoints, market access comparators, and payer positioning across dozens of competing programmes. Pienomial's Knolens platform enables CI teams to track these signals continuously and structure them into traceable, source-attributed intelligence that supports faster strategic response. [9]
1. Merck Respiratory Portfolio: Strategic Context and Revenue Pressure
Keytruda dominates Merck's respiratory-adjacent revenue base through its broad NSCLC franchise. Lung cancer accounts for 27.4% of Keytruda's total market share by application, making it the single largest indication by revenue. The approaching 2028 patent expiry, with US core composition-of-matter protection ending and biosimilar regulatory submissions potentially as early as 2026 or 2027, is creating urgent pressure to extend the franchise through subcutaneous formulations, new indication approvals, and next-generation combination strategies.
Merck's response to the Keytruda patent cliff is multi-layered: a subcutaneous pembrolizumab formulation (MK-3475A) has already received FDA and EMA approvals, extending the commercial position against biosimilar intravenous equivalents.[7] New indication filings, including the February 2025 FDA Priority Review for perioperative head and neck squamous cell carcinoma based on the KEYNOTE-689 trial, are broadening the approved label to create method-of-use patent protection that extends beyond the core molecule expiry date.
2. NSCLC: Keytruda's Competitive Position Under Intensifying Pressure
Keytruda's NSCLC dominance in 2026 covers first-line monotherapy in PD-L1 high patients, first-line with chemotherapy across all-comers, and a growing adjuvant and neoadjuvant footprint. The breadth of the franchise creates a structural competitive moat that is genuinely difficult to challenge, but three threat vectors are accelerating.
The first is the BMS Opdualag (nivolumab plus relatlimab) NSCLC expansion. In 2024, BMS disclosed the Phase III RELATIVITY-1093 trial evaluating Opdualag plus chemotherapy in first-line non-squamous NSCLC patients with PD-L1 between 1% and 49%, using Keytruda plus chemotherapy as the direct comparator. [3] For competitive intelligence in pharma teams at Merck, this represents the first registrational-stage trial in NSCLC that is explicitly designed to demonstrate superiority over Keytruda, not non-inferiority. The readout is expected to be a binary signal event: either BMS establishes a new evidence bar in this population, or it validates Keytruda's durability.
The second threat vector is the broader next-generation I-O combination landscape. Multiple TIGIT inhibitor, LAG-3 antibody, and bi-specific programmes are in Phase II and Phase III in NSCLC, each targeting a differentiation claim over Keytruda monotherapy or combinations. The CI implication: the standard-of-care comparator in NSCLC HTA submissions will shift if any of these combinations achieves regulatory approval, requiring Merck to defend Keytruda's market access position across NICE, G-BA, and HAS with updated evidence.
The third vector is the 2028 LOE itself. Multiple biosimilar pembrolizumab development programmes are underway, with regulatory submissions potentially arriving at FDA before the patent expiry, positioning biosimilars for potential market entry in 2028.For any company with an NSCLC programme considering Keytruda as a comparator, the commercial timeline from 2028 onward is relevant to market access scenario planning.
3. Enflonsia (Clesrovimab): The RSV Market Entry
On 9 June 2025, the FDA approved clesrovimab-cfor (Enflonsia) for the prevention of RSV lower respiratory tract disease in newborns and infants entering their first RSV season, making Merck the second entrant in the long-acting RSV monoclonal antibody market behind Sanofi and AstraZeneca's Beyfortus (nirsevimab).[6]
The CLEVER Phase 2b/3 trial results supporting the approval demonstrated that Enflonsia reduced the incidence of RSV disease compared to placebo by 60% and reduced RSV-associated hospitalisations by 84% over five months.Merck set the wholesale acquisition cost at $556 per dose, matching Beyfortus exactly. The differentiation strategy rests on a single-dose, weight-independent formulation: unlike Beyfortus, which requires two different-sized doses depending on infant weight, Enflonsia is administered as a single 105mg dose regardless of weight, potentially reducing dosing errors in paediatric practice. [5]
The ACIP formally recommended clesrovimab in August 2025, making it the second RSV antibody with a CDC recommendation for all infants entering their first RSV season, expanding provider and formulary access for the 2025 to 2026 RSV season.
The competitive dynamics between Enflonsia and Beyfortus are now primarily commercial rather than clinical: both products are approved, both are priced at the same WAC, and both have ACIP recommendations. Merck's market share capture in the 2025 to 2026 season will be the key signal for CI teams tracking the RSV landscape at Sanofi, AstraZeneca, and Pfizer.
4. Market Access Implications of the Enflonsia Launch
The entry of Enflonsia into the RSV prophylaxis market creates specific pharma market monitoring questions for competing organisations. For Sanofi and AstraZeneca, the immediate concern is formulary access: will payers, pharmacy benefit managers, and hospital systems maintain exclusive Beyfortus preferred status or create a dual-preferred tier that splits market share? Merck's price parity strategy removes cost as a differentiator, making formulary decisions contingent on clinical differentiation, logistical convenience, and payer contracting terms.
For HTA bodies that will assess Enflonsia in Europe and other markets, the evidence package requires a direct or indirect comparison with Beyfortus. The absence of a head-to-head trial between the two products creates an ITC requirement, with all the methodology documentation obligations that NICE, HAS, and other bodies impose. CI teams at Merck must monitor how each HTA body frames the comparative assessment and whether the single-dose advantage is classified as a patient-relevant benefit or a convenience factor with limited weighting in formal assessments.
For Pfizer, whose maternal RSV vaccine Abrysvo competes in the prevention strategy landscape, the dual-antibody market creates a different dynamic: both Enflonsia and Beyfortus compete with the maternal vaccination approach, and palivizumab's December 2025 market withdrawal removes an older product from the formulary, creating space that both antibody products will compete to fill.
5. The Subcutaneous Pembrolizumab Strategy
Merck's approval of a subcutaneous formulation of pembrolizumab (MK-3475A, marketed as subcutaneous Keytruda) in both the US and EU is one of the most strategically significant lifecycle management moves in recent pharmaceutical history.By delivering pembrolizumab via subcutaneous injection, Merck can offer patients and providers a more convenient administration route than the IV infusion required by biosimilar equivalents, creating a product experience differentiation that supports premium pricing and formulary retention even after IV biosimilars enter the market.
The formulation patent strategy is layered: subcutaneous formulation patents, device patents covering the administration system, and method-of-treatment patents for indications approved under the subcutaneous label may each individually extend the commercial exclusivity of the subcutaneous product beyond the 2028 core molecule expiry. For competitive intelligence pharmaceutical industry teams tracking Merck's patent strategy, the subcutaneous filing and any litigation dynamics around biosimilar entry are high-priority signal categories.
6. Signals That Respiratory CI Teams Are Missing
The headline signals in Merck's respiratory portfolio, Keytruda label expansions, Enflonsia commercial launch data, and subcutaneous pembrolizumab uptake metrics, are the signals every CI analyst tracks. The signals that create genuine strategic lead time are the earlier-stage indicators that require systematic source monitoring to detect reliably.
Six signal types deserve specific attention for Merck respiratory CI. First, Phase I protocol uploads in NSCLC and SCLC on ClinicalTrials.gov and CTIS reveal new combination strategies twelve to eighteen months before data. Second, FDA Type B meeting requests visible in agency dockets reveal regulatory strategy decisions for new submissions six to twelve months ahead of BLA or sNDA filings. Third, payer formulary placement decisions in the Enflonsia versus Beyfortus competition are appearing in pharmacy benefit announcements and hospital formulary committee minutes, providing early market access signals. Fourth, academic investigator-initiated study activations at major respiratory oncology centres provide early signals of scientific interest in emerging Keytruda combination approaches. Fifth, EudraCT and CTIS filings capture European programme initiations not always simultaneously reflected in US registry databases. Sixth, the Merck earnings call language on respiratory pipeline investment priorities provides strategic context that shapes the CI team's forward-looking scenario planning.
7. Competitive Implications for Rival Programmes
Merck's respiratory portfolio creates direct implications for competing programmes across three competitive dimensions.
For NSCLC programmes, the Keytruda 2028 LOE timeline is a market access planning input. Products entering the NSCLC market in 2027 or later will face a commercial landscape in which biosimilar pembrolizumab is approaching or entering the market. The comparator for HTA submissions will increasingly be the IV or subcutaneous pembrolizumab combination, priced under growing biosimilar pressure, which affects the relative value narrative for any product seeking a premium over pembrolizumab-based standard of care.
For RSV programmes, the Enflonsia approval establishes the two-product RSV antibody market as a stable competitive structure for the near term. Any new entrant into the infant RSV prophylaxis space must now demonstrate clinical differentiation from both Beyfortus and Enflonsia to achieve formulary access, raising the evidence bar for pipeline RSV antibodies in Phase II and III.
For programmes in the broader respiratory infectious disease space, including COPD, asthma, and human metapneumovirus, the Merck RSV commercial execution provides a market access template: the ACIP recommendation process, paediatric formulary dynamics, and payer contracting strategies that Merck navigates with Enflonsia are directly applicable to the strategic planning of any competing respiratory programme targeting the same clinical infrastructure.
8. How AI Enables Continuous Merck Respiratory Intelligence
Merck's respiratory portfolio spans at minimum three distinct therapeutic areas simultaneously: oncology (NSCLC, HNSCC), infectious disease (RSV), and pulmonary medicine (COPD, asthma pipeline assets). Each area has different primary signal sources, different conference calendars, different regulatory timelines, and different CI team stakeholders within a competing organisation. Manual CI tracking across all three simultaneously is structurally difficult to sustain at the speed and coverage that competitive therapeutic areas require.
Knolens operates as an enterprise intelligence platform that continuously ingests and classifies Merck-relevant respiratory signals from all relevant source types, covering ClinicalTrials.gov and CTIS protocol uploads, FDA and EMA regulatory filing databases, ASCO, ESMO, IDWeek, ATS, and ERS conference abstracts, payer press releases and formulary announcements, SEC filings and earnings call transcripts, patent databases, and primary journal publications.
The classification architecture is tiered by signal type and urgency: a Keytruda FDA priority review designation for a new indication is a high-priority signal routed to the oncology CI team with immediate context. An Enflonsia payer formulary decision is a high-priority signal for the RSV commercial team. A Phase I protocol upload for a new Merck respiratory asset is a medium-priority signal for research strategy. Each signal carries full source attribution, enabling the CI team to verify primary sources and assess signal reliability before acting on the intelligence.
9. How Quickly Can Your Team Go Live with Merck Respiratory CI on Knolens?
Configuring a structured Merck respiratory CI programme on Knolens does not start with a scoping exercise or a build phase. Knolens ships with pre-built signal monitoring across all three Merck respiratory areas simultaneously, covering oncology, infectious disease, and pulmonary medicine from day one. The platform is configured to your competitive scope, not constructed around it.
Most CI teams are receiving live Merck respiratory alerts within two weeks of onboarding. Here is what that looks like.
Sprint 1, Weeks 1 to 2, Full Merck respiratory monitoring live: Knolens is configured to your portfolio's competitive overlap with Merck. Pre-built signal feeds are activated across ClinicalTrials.gov and CTIS for NSCLC and RSV programmes, FDA sNDA and BLA filing databases, ASCO, ESMO, IDWeek, ATS, and ERS conference abstract monitoring, CDC ACIP proceedings for RSV formulary intelligence, SEC filings and earnings call transcripts, and patent continuation filings for subcutaneous pembrolizumab. Your team receives the first structured Merck respiratory signal digest within days. No source mapping required from your side. [9]
Sprint 2, Weeks 3 to 4, Signal tiers and cross-functional routing configured: Knolens routes each signal type to the appropriate internal team automatically. A Keytruda LOE litigation outcome goes to commercial strategy with modelling context. An Enflonsia payer formulary placement decision goes to the RSV market access team. A Phase I NSCLC protocol upload goes to clinical development as a horizon signal. Each function receives exactly the Merck intelligence relevant to their decisions, without a CI analyst manually triaging and distributing.
Sprint 3, Weeks 5 to 6, Response frameworks loaded: For each high-priority Merck signal type, pre-built response frameworks are configured in Knolens. If a Keytruda biosimilar achieves FDA approval before the 2028 expiry, the framework immediately surfaces your NSCLC market access implications, your comparator landscape update, and your pricing strategy checklist. If Enflonsia gains a payer-preferred formulary position in a key US market, the RSV competitive response framework activates automatically with the relevant context for your programme. [7]
From Sprint 3 onward, Knolens runs Merck respiratory CI continuously without scheduled analyst checking cycles. Signals across all three therapeutic areas are ingested, classified, and routed in hours. Coverage is comprehensive. Latency is eliminated.
Conclusion
Merck's respiratory portfolio in 2026 is a convergence of strategic complexity: a blockbuster facing its most significant patent challenge, a new product entry into an established two-player market, and a formulation lifecycle strategy that will define the commercial transition through the 2028 to 2030 period. Each element generates signals that affect competing programmes across oncology, infectious disease, and respiratory medicine.
For CI teams at organisations competing in any of these spaces, the quality of Merck respiratory intelligence is not a secondary concern. It is a direct input to protocol design, market access scenario planning, and commercial strategy. Pienomial's Knolens platform delivers continuously updated, source-attributed Merck respiratory intelligence as a purpose-built pharma competitive intelligence capability, giving teams the lead time they need to respond before the competitive landscape has moved around them. CTA: Request a Therapeutic Area CI Briefing from Pienomial.
