--- title: "Primary and Secondary Endpoints, Definition | MedTech Terms" description: "The pre-specified outcomes that determine trial success (primary), provide supporting evidence (secondary), or generate hypotheses (exploratory)." lang: en json-ld: | { "@context": "https://schema.org", "@graph": [ { "@type": "DefinedTerm", "@id": "https://medtechterms.com/terms/primary-secondary-endpoint#term", "name": "Primary and Secondary Endpoints", "alternateName": [ "Primary endpoint", "Secondary endpoint", "Exploratory endpoint" ], "description": "The primary endpoint is the pre-specified outcome on which the trial is statistically powered and on which trial success or failure is judged. Secondary endpoints provide supporting evidence, additional efficacy claims, safety, or quality-of-life, and are typically tested under a pre-specified hierarchical or alpha-allocation procedure to control multiplicity. 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[Home](/) 2. / 3. [Terms](/terms) 4. / 5. [Clinical & Trials](/terms?cat=Clinical%20%26%20Trials) 6. / 7. Primary and Secondary Endpoints [All terms](/terms) Clinical & Trials [Clinical Evidence](/ecosystems/clinical-evidence) # Primary and Secondary Endpoints The pre-specified outcomes that determine trial success (primary), provide supporting evidence (secondary), or generate hypotheses (exploratory). Reviewed by [Christian Espinosa, Founder, Blue Goat Cyber](/authors/christian-espinosa) Last reviewed May 9, 2026 ## Definition The primary endpoint is the pre-specified outcome on which the trial is statistically powered and on which trial success or failure is judged. Secondary endpoints provide supporting evidence, additional efficacy claims, safety, or quality-of-life, and are typically tested under a pre-specified hierarchical or alpha-allocation procedure to control multiplicity. Exploratory endpoints generate hypotheses for future studies and do not support label or coverage claims. Endpoint choice and ordering is the single most consequential design decision in a [pivotal trial](/terms/pivotal-trial). What the regulation says ICH E9 'Statistical Principles for Clinical Trials' and ICH E9(R1) addendum on Estimands govern endpoint specification. FDA's 'Multiple Endpoints in Clinical Trials' guidance (2022) details multiplicity control. ## What this means in practice MedTech sponsors increasingly use composite primary endpoints (MACE in cardiovascular, KCCQ in heart failure) and pre-specify hierarchical secondary testing to maximize labelable claims. Common pitfalls - • Adding endpoints during trial conduct, almost always destroys their interpretability. - • Failing to control multiplicity across secondary endpoints, leaving label claims unsupported. ## Related terms Grouped by theme ### Editor's picks · Hand-selected related concepts [ Clinical & Trials Surrogate Endpoint Biomarker or intermediate outcome used as a substitute for a clinical endpoint in regulatory decisions. ](/terms/surrogate-endpoint)[ Clinical & Trials Pivotal Trial Definitive clinical study designed to establish safety and effectiveness for marketing authorization. ](/terms/pivotal-trial)[ Clinical & Trials Composite Endpoint Single endpoint combining multiple component outcomes (e.g., MACE = death + MI + stroke). ](/terms/composite-endpoint)[ Clinical & Trials Non-Inferiority Trial A trial designed to demonstrate that a new intervention is not worse than an active comparator by more than a pre-specified, clinically acceptable margin. ](/terms/non-inferiority-trial) ### Clinical Trials & Evidence · From this learning path [ Clinical & Trials Protocol Deviation Departure from the approved clinical investigation plan. Adjacent lesson ](/terms/protocol-deviation?from=clinical-trials-and-evidence)[ Clinical & Trials Adaptive Trial Design Trial design that pre-specifies opportunities to modify aspects (sample size, arms, endpoints) based on interim data. ](/terms/adaptive-trial?from=clinical-trials-and-evidence)[ Clinical & Trials Adverse Event(AE) Any untoward medical occurrence in a subject, whether or not related to the device. ](/terms/adverse-event?from=clinical-trials-and-evidence)[ Clinical & Trials Clinical Evaluation Report(CER) Documented assessment of clinical data demonstrating EU MDR conformity for a device. ](/terms/cer?from=clinical-trials-and-evidence) Cited by Where this term appears across MedTech Terms. Learning paths (1) - [Clinical Trials & Evidence](/paths/clinical-trials-and-evidence)Lesson 10 of 18 Ecosystems (1) - [Clinical Evidence](/ecosystems/clinical-evidence) ## Primary references 3 sources Link health: 3 verified · last checked 2026-06-20 FDA· 1 ICH· 2 1. [1 FDA, Multiple Endpoints in Clinical Trials (2022) Verified FDA · fda.gov ](https://www.fda.gov/regulatory-information/search-fda-guidance-documents/multiple-endpoints-clinical-trials-guidance-industry) 2. [2 ICH E9(R1) Estimands Verified ICH · ich.org ](https://www.ich.org/page/efficacy-guidelines) 3. [3 ICH Guidelines Verified ICH · ich.org ](https://www.ich.org/page/ich-guidelines) Inline markers like \[1\] jump to the matching reference above. Sponsor note ### Clinical evidence intersecting with device security? We support clinical-stage MedTech teams whose investigational devices touch patient data or hospital networks. [Book a 30-minute discovery session](https://go.bluegoatcyber.com/meetings/blue-goat-cyber/discovery-session) - No obligation - Expert-led from minute one - NDA available on request MedTech Terms is a community resource sponsored by [Blue Goat Cyber](https://bluegoatcyber.com). Definitions are independent of any vendor. On this term Category Clinical & Trials Sources 3 Updated 5/9/2026 [Compare with another term](/compare?a=primary-secondary-endpoint) Learn in 60 seconds Card Lesson Quiz The pre-specified outcomes that determine trial success (primary), provide supporting evidence (secondary), or generate hypotheses (exploratory). - · MedTech sponsors increasingly use composite primary endpoints (MACE in cardiovascular, KCCQ in heart failure) and pre-specify hierarchical secondary testing to maximize labelable claims. - · Exploratory endpoints generate hypotheses for future studies and do not support label or coverage claims. Remember this Watch out: Adding endpoints during trial conduct, almost always destroys their interpretability. Related terms - [Pivotal Trial ](/terms/pivotal-trial) - [Composite Endpoint ](/terms/composite-endpoint) - [Surrogate Endpoint ](/terms/surrogate-endpoint) - [Sample Size and Statistical Power ](/terms/sample-size-power) - [Non-Inferiority Trial ](/terms/non-inferiority-trial) You may also need Auto-suggested from Clinical & Trials and shared keywords. - [Feasibility Study ](/terms/feasibility-study) - [Contract Research Organization(CRO) ](/terms/cro) - [Investigator-Initiated Trial(IIT) ](/terms/investigator-initiated-trial) - [Master Protocol (Basket / Umbrella / Platform) ](/terms/master-protocol) - [Adaptive Trial Design ](/terms/adaptive-trial) - [Bayesian Trial Design ](/terms/bayesian-trial) [All Clinical & Trials terms](/terms?cat=Clinical%20%26%20Trials) From the Blue Goat network Related resources and services on this topic. - [ MedTech Launchpad MedTech funding rounds, accelerators, and launch resources. ](https://medtechlaunchguide.com) MedTech Terms An authoritative, plain-language reference for the regulatory, quality, cybersecurity, and software terms that shape modern medical devices. 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