Merck Q1 2026: Growth in Oncology and Animal Health, But GAAP EPS Dips on Acquisition Charges

Executive snapshot

Merck & Co. (MRK) delivered a press-release style update for the first quarter of 2026 that reads like a map of the company’s near-term growth engines and its longer-run pipeline bets. Total worldwide sales came in at $16.3 billion, up 5% on a reported basis and up 3% on a constant-exchange-rate basis. The headline numbers showcase a company still leaning on its cancer franchise and on new launches to prop up the top line, even as it absorbs a sizable one-off charge tied to an acquisition.

On the earnings line, GAAP loss per share was $1.72 and Non-GAAP loss per share was $1.28. Both figures include a per-share charge of $3.62 related to the acquisition of Cidara. In short, the quarter’s profitability is clouded by acquisition accounting, even as the underlying business continues to demonstrate scale in key areas.

Segment and product highlights

The company’s results underscore a portfolio anchored by durable oncology demand and expanding contributions from launches across therapeutic areas:

• KEYTRUDA / KEYTRUDA QLEX sales were $8.0 billion, up 12% on a reported basis and 8% ex-FX. The mix includes KEYTRUDA QLEX sales of $128 million. The performance points to continued momentum in immuno-oncology but carries the same caveats that any monoclonal antibody franchise faces—pricing pressures, competition, and payer dynamics.
• WINREVAIR sales were $525 million, up 88% (87% ex-FX). This is a standout growth line that reflects a successful product expansion or novel indication adoption, albeit on a smaller base.
• Animal Health sales were $1.8 billion, up 13% (6% ex-FX). The animal-health engine remains a steady accelerator, providing a counterweight to the more manufacturing-costly human-health dynamics.
• The presentation also notes a clear acknowledgment of the Cidara acquisition, with the per-share charge embedded in both GAAP and Non-GAAP results. The implied hurdle rate for integrating this acquisition will be a focal point for investors poring over future earnings cadence.

Earnings structure and what it portends

From a reporting standpoint, the quarter is a reminder that earnings per share are as much about one-off charges as about operating performance. The GAAP loss per share of $1.72 is paired with a Non-GAAP loss per share of $1.28; both figures include a $3.62 per-share charge associated with acquiring Cidara. The combination means the ongoing operating leverage and margin trajectory will be parsed against the backdrop of this accounting burden in any near-term sentiment about EPS trajectory.

Analysts typically assemble a view around the EPS consensus prior to the print, then measure the actual earnings surprise against it. The release itself doesn’t publish a formal consensus figure, so the market will look to Street estimates for a comparison. In that sense, the quarter’s narrative is less about a clean beat or miss and more about how the core franchises—especially oncology and launches—carry the day when attached to the company’s adjusted earnings baseline.

There isn’t a stated revenue forecast in the release—this is common when a company emphasizes current-quarter results and regulatory/licensing milestones over forward-looking revenue guidance. Still, the size and pace of top-line expansion, driven by KEYTRUDA and newer launches, suggests a path toward implied revenue growth that investors will test against upcoming quarters.

Pipeline, regulatory milestones, and near-term catalysts

The press materials highlight several pipeline and regulatory milestones that could shape not only Merck’s trajectory but also sentiment across peers in the sector:

• Cardio-Pulmonary data presented at ACC.26, including positive results from the Phase 3 CORALreef AddOn trial. Positive cardiopulmonary data can broaden the addressable market for a company’s cardiovascular portfolio and may influence collaboration and development strategy.
• IDVYNSO received U.S. FDA approval as a once-daily, oral treatment for certain adults with virologically suppressed HIV-1. This approval signals expansion into anti-viral/antiretroviral territory and adds to Merck’s diversification across therapeutic areas.
• “Multiple significant regulatory and clinical milestones across the oncology pipeline” are cited, reinforcing a theme of ongoing clinical activity and potential inflection points for future quarters.

Acquisition accounting and strategic implications

The $3.62 per-share charge tied to acquiring Cidara is a reminder that inorganic growth comes with a front-loaded hit to reported earnings. The market will ask whether the synergy story and potential cross-portfolio benefits can overcome the near-term drag on reported EPS and whether the combined entity can translate pipeline milestones and new approvals into durable cash flow growth over time.

Beyond the numbers, the Cidara integration has implications for Merck’s capital allocation and risk management. Investors will watch for the durability of return on invested capital, the timing of cost synergies, and how the acquisition reshapes the company’s R&D sequencing and external collaborations in a competitive landscape.

Market and sector read-through

Sector peers are likely to parse Merck’s results for signals about sustainable growth versus one-off drivers. If KEYTRUDA’s momentum remains resilient and animal-health performance maintains its upside, Merck could outpace some pharma peers that rely more heavily on a single product cycle. The regulatory and clinical milestones across the oncology pipeline also put a spotlight on how long-stage trials and regulatory timelines can alter the earnings story in ways that aren’t always predictable from quarter to quarter.

In a broader sense, the combination of strong product-level performance with a non-cash dilution of ownership through an acquisition charge presents a familiar CFO calculus: how to balance near-term GAAP optics with a longer-term narrative about EBITDA quality and free cash flow trajectory. For sector peers, the takeaway is to watch both the growth engines and the cost of inorganic moves when forming projections.

Bottom line and takeaways

Merck’s Q1 2026 results reinforce a two-track reality: core franchises deliver scale and resilience, while accounting actions tied to acquisitions create a drag on reported earnings in the near term. The top line shows confidence in oncology and launches, and the pipeline cadence suggests ongoing catalysts that could support earnings quality in the medium term.

For investors tracking MRK, the next steps will be to compare the implied trajectory of EPS and operating margin against the evolution of the KEYTRUDA franchise, the performance of WINREVAIR and Animal Health, and the impact of the Cidara integration. The absence of an explicit revenue forecast means attention will shift to quarterly cadence and pipeline milestones to gauge how quickly the company can translate top-line gains into sustainable profitability.