SARMs Clinical Trial Design Guide: Effective Research

Designing Effective Clinical Trials for SARMs in Australia

Start With the Australian Clinical and Regulatory Reality

Define the Investigational Product Clearly

• Molecule identity and quality: GMP-grade material, full characterisation, stability, impurity profile and validated bioanalytical methods.
• Mechanism and selectivity claims: Document receptor binding and selectivity, tissue-selective effects and the translational rationale from preclinical data.
• Product risk posture: Assume risk is unknown until demonstrated. Plan conservative dose escalation and intensive safety monitoring.

Align Early With Australian Regulators and Ethics Oversight

• TGA clinical trial pathway: Determine whether the study will proceed under the Clinical Trial Notification (CTN) scheme or Clinical Trial Approval (CTA) scheme and plan sponsor responsibilities accordingly [1].
• HREC review: Obtain approval from a Human Research Ethics Committee (HREC) in line with the National Statement on Ethical Conduct in Human Research [2].
• Good Clinical Practice: Build the trial around ICH GCP expectations covering roles, monitoring, data integrity and safety reporting, as commonly adopted in Australian clinical trial conduct [5].

Clarify the Study Objective and Required Decision

Write objectives that translate directly into design choices and match the intended indication rather than enhancement claims.

Typical Primary Objectives for SARM Development Programs

• Phase 1: Safety and tolerability, pharmacokinetics (PK) and pharmacodynamic (PD) signals, such as biomarkers related to lean mass, in a controlled setting.
• Phase 2: Dose-finding, preliminary efficacy on clinically meaningful endpoints and continued safety characterisation.
• Phase 3: Confirmatory efficacy and safety, benefit–risk in target populations and longer follow-up.

Define Endpoints That Match the Study Intent

• Functional benefit: Prioritise functional endpoints, such as stair climb power, six-minute walk distance and grip strength, rather than lean mass alone.
• Osteoporosis or bone outcomes: Use bone density and fracture-related endpoints with an adequate study duration.
• Cachexia or sarcopenia: Combine body composition and function with patient-reported outcomes (PROs).

Focus Compounds and Their Research Context

Note: The compounds below are often discussed together online, but they are not all SARMs. In a research context, the rationale typically relates to potential effects on muscle, bone, metabolism or recovery from disease. None should be assumed safe or effective outside regulated trials.

MK-2866 (Ostarine, Enobosarm or GTx-024)

• Class: Non-steroidal androgen receptor modulator (SARM).
• Research rationale: Non-steroidal AR modulation intended to improve lean body mass and potentially physical function in catabolic conditions, including cancer cachexia and other wasting states [9].
• Why it fits clinical trials: MK-2866 or enobosarm has a more visible history of formal clinical development than many research chemicals, making it a more typical example when discussing SARM trial design.
• Protocol emphasis: Pair body composition with function, including SPPB, six-minute walk and stair climb assessments. Prespecify endocrine, lipid and hepatic monitoring and stopping thresholds.

LGD-4033 (Ligandrol)

• Class: Non-steroidal androgen receptor modulator (SARM).
• Research rationale: Early human trials examined PK, PD and short-term anabolic signals such as lean mass changes, supporting exploration in muscle wasting and sarcopenia programs [10].
• Protocol emphasis: Even in short studies, include endocrine laboratory tests, lipid monitoring and systematic adverse-event capture. Avoid overstating clinical benefit from surrogate endpoints alone.

S-4 (Andarine)

• Class: Non-steroidal androgen receptor modulator with largely preclinical and limited public human data.
• Research rationale: Primarily driven by preclinical AR modulation and tissue-selectivity claims [11].
• Evidence caution: Public, peer-reviewed human trial evidence is limited relative to compounds such as enobosarm or LGD-4033. Treat S-4 as highly uncertain in the risk assessment.
• Protocol emphasis: If advanced clinically, require strong governance through a Data and Safety Monitoring Board (DSMB), conservative dosing, clear stopping rules and informed consent language addressing unknown risks.

RAD140 (Testolone)

• Class: Non-steroidal androgen receptor modulator with limited public human trial literature.
• Research rationale: Preclinical AR activity and proposed anabolic effects have generated interest in muscle and bone indications [12].
• Evidence caution: Compared with better-characterised clinical candidates, public clinical evidence is limited. Any clinical program would require robust toxicology and a conservative first-in-human approach.
• Protocol emphasis: Consider high-frequency early hepatic and lipid testing, cardiovascular screening and a clear prohibition on confounding co-exposures such as anabolic agents and certain supplements.

MK-677 (Ibutamoren)

• Class: Ghrelin receptor agonist and growth hormone secretagogue, not a SARM.
• Research rationale: MK-677 raises GH and IGF-1 signalling and has been studied for possible effects on body composition, frailty and catabolic states in some populations [13].
• Key difference from SARMs: Its mechanism is endocrine and metabolic rather than direct AR modulation, so its endpoints and safety monitoring differ.
• Protocol emphasis: Monitor fasting glucose, HbA1c, fluid retention, oedema, blood pressure and other metabolic effects. Define clear criteria for discontinuation related to hyperglycaemia.

GW0742

• Class: PPARδ agonist, not a SARM, and primarily a preclinical research compound.
• Research rationale: Research interest relates to metabolic regulation and endurance-related pathways in non-clinical models [14].
• Evidence caution: GW0742 is not a standard clinical-development candidate. Any move towards human research would require exceptional preclinical safety justification and transparent discussion of risks.
• Protocol emphasis: Toxicology must be decisive, and the protocol must address longer-term risks and monitoring beyond typical short anabolic studies.

Sport Integrity Considerations

Many SARMs and related agents are prohibited in sport [8]. If the target population includes competitive athletes, address this explicitly in the eligibility criteria and informed consent, and consider documenting each participant’s sport participation status.

Build a Protocol Structure That Survives Scrutiny

Use a standard protocol framework so HRECs, sites and monitors can quickly verify safety, validity and compliance.

Recommended Protocol Sections

1. Synopsis: Population, intervention, comparator, endpoints, duration and key safety considerations.
2. Background and rationale: Preclinical and clinical evidence, intended indication and known or anticipated risks.
3. Objectives and hypotheses.
4. Design: Phase, randomisation, blinding, control and number of sites.
5. Population: Inclusion and exclusion criteria, recruitment and vulnerable populations.
6. Treatment: Dose, route, schedule, escalation and compliance.
7. Assessments: Efficacy, PK, PD, safety and visit schedule.
8. Safety management: AE and SAE reporting, stopping rules and DSMB oversight.
9. Statistics: Estimands, sample size, analysis sets and missing-data plan.
10. Operational plan: Monitoring, data handling and audits.
11. Ethics: Consent, confidentiality, compensation and contraception.
12. Registration and reporting: ANZCTR registration and publication plan.

Use SPIRIT for Protocol Completeness

SPIRIT provides a widely used checklist intended to prevent protocol omissions that can later cause delays or bias, including unclear outcomes, analysis plans or monitoring arrangements [6].

Choose the Control, Randomisation and Blinding Design

Comparator Selection

• Placebo-controlled: Common for early efficacy studies, but it must be ethically justified and paired with rescue treatment or standard care when appropriate.
• Active-controlled: Important when a standard of care exists and useful for evaluating comparative benefit–risk.
• Add-on design: Investigational agent plus standard care compared with placebo plus standard care, which can improve ethics and generalisability.

Randomisation Basics That Reduce Bias

• Method: Use computer-generated sequences and allocation concealment through central randomisation or another controlled process that prevents prediction.
• Stratification: Consider key prognostic factors, including sex, baseline functional status, baseline lean mass and site.
• Block size: Use varying block sizes to reduce predictability.

Blinding and Unblinding

• Double-blind when feasible: Reduces performance and detection bias.
• Emergency unblinding: Define who can unblind, how it will occur and when it is permitted, such as for a suspected unexpected serious adverse reaction.
• Blinding integrity checks: Optionally assess whether participants or investigators can identify the assigned treatment.

Population, Screening and Risk Controls

Align Inclusion and Exclusion Criteria With the Indication

Because AR modulators can influence endocrine, hepatic, lipid and cardiovascular systems, typical criteria often address:

• Baseline liver function: Exclude significant hepatic disease and define ALT and AST cut-offs.
• Cardiovascular risk: Consider excluding unstable cardiovascular disease and predefine blood pressure and ECG thresholds.
• Endocrine considerations: Assess baseline testosterone and gonadotropins and exclude uncontrolled endocrine disorders as appropriate.
• Concomitant medicines and supplements: Prohibit anabolic steroids, certain hormones and other agents that could confound endpoints or increase risk.
• Pregnancy prevention: Apply strict contraception requirements and pregnancy testing when relevant.

Common Screening Workflow

1. Prescreen for eligibility and collect medicine and supplement history.
2. Obtain informed consent before any study-specific procedures.
3. Complete the medical history and physical examination.
4. Obtain baseline laboratory tests, including CBC, CMP, lipids and an endocrine panel where relevant.
5. Complete an ECG and an echocardiogram if indicated.
6. Measure baseline body composition, such as through DXA, and complete functional tests.
7. Randomise only after confirming full eligibility.

Dosing Strategy, Adherence and Exposure

Conservative Phase 1 Escalation

• Sentinel dosing: Dose a small number of participants before dosing the full cohort.
• Escalation rules: Define dose-limiting toxicity and stopping thresholds clearly.
• Food effect: Consider a cohort that assesses fed versus fasted PK where relevant.

Adherence Measurement

• Participant records: Use pill counts, diaries and electronic patient-reported outcome timestamps.
• Exposure checks: Use PK spot checks where feasible.
• Protocol deviations: Define deviations and their statistical handling in advance.

Choose Efficacy Endpoints That Matter

Body Composition Outcomes

• Lean mass measured by DXA: Common, but it can overstate clinical value when it is not paired with a functional endpoint.
• Muscle volume measured by MRI or CT: More specific but costly and potentially better suited to a substudy.

Functional Outcomes

• Mobility and performance: Stair climb test, six-minute walk test and short physical performance battery.
• Strength: Grip strength, leg press strength and isokinetic testing using standardised equipment and training.
• Disease-related function: Falls, mobility milestones or disease-specific functional scales where applicable.

Patient-Reported Outcomes

• Relevant measures: Quality-of-life and fatigue scales appropriate to the intended indication.
• Clinical interpretation: Predefine minimal clinically important differences when available.

Anticipate and Monitor the Main Safety Risks

Androgen-modulating and related investigational agents may carry risks affecting the liver, lipids, cardiovascular system and endocrine function. A trial should assume meaningful risk is plausible until proven otherwise and manage that risk conservatively.

Core Safety Domains and Assessments

• Hepatic: Monitor ALT, AST, ALP, bilirubin and symptoms such as jaundice or right upper-quadrant pain at baseline, frequently during the early treatment period and at regular intervals thereafter.
• Cardiovascular: Monitor blood pressure, heart rate, ECG results and symptoms such as chest pain or dyspnoea at baseline and periodically, with additional monitoring for identified risks or signals.
• Lipids and metabolism: Monitor HDL, LDL, triglycerides, glucose and HbA1c where relevant at baseline and periodically according to the study phase.
• Endocrine and reproductive: Monitor testosterone, LH and FSH as appropriate, menstrual history and pregnancy testing at baseline, periodically and during follow-up after discontinuation.
• General safety: Monitor CBC, renal function, urinalysis, adverse events and concomitant medicines at baseline and according to the protocol schedule.

Adverse-Event Capture, Grading and Reporting

• AE definitions and collection: Specify collection windows, intensity grading, relatedness and expectedness.
• Standardised grading: Use an accepted toxicity-grading approach appropriate to the population.
• Safety reporting: Define timelines and responsibilities for SAE and SUSAR reporting under the protocol, HREC requirements and applicable TGA clinical trial pathway [1].

Stopping Rules and Safety Governance

• Pre-specified stopping rules: Establish thresholds for laboratory abnormalities, serious cardiovascular events and unexpected patterns.
• DSMB or Independent Data Monitoring Committee: Strongly recommended for moderate-to-high-risk programs or later phases.
• Risk mitigation: Use conservative dosing, frequent early monitoring and clear discontinuation criteria.

Statistics, Estimands and Missing Data

Sample Size and Power

• Primary endpoint: Base statistical power on the primary endpoint and a realistic effect size, ideally informed by Phase 2 or strong preliminary data.
• Participant attrition: Allow for dropout, non-adherence and missing assessments, particularly in functional testing.

Define Estimands and Analysis Sets

• Estimand: Specify the effect being estimated, such as a treatment-policy effect or a hypothetical effect under full adherence.
• Analysis populations: Use intention-to-treat as the primary efficacy population, a safety set containing participants who received at least one dose and a per-protocol population as supportive analysis.

Missing-Data Plan

• Statistical methods: Predefine approaches such as mixed models for repeated measures, multiple imputation and sensitivity analyses.
• Intercurrent events: Document how events such as hospitalisation or treatment discontinuation will be handled.

Operational Quality and Audit Readiness

• Electronic data capture: Use validated systems with audit trails and role-based access.
• Monitoring plan: Apply risk-based monitoring consistent with GCP and define the source-data verification approach [5].
• Training and standardisation: Use standardised equipment, scripts and rater training for functional tests to reduce variability.
• Privacy and confidentiality: Align data handling with applicable Australian privacy requirements and site-governance policies.
• Drug accountability: Document chain of custody, storage conditions and reconciliation.

Transparency, Registration and Reporting

• Register the trial: Consider registration with the Australian New Zealand Clinical Trials Registry before enrolment to support transparency and publication requirements [4].
• Report using CONSORT: Plan reporting tables and diagrams covering participant flow, baseline characteristics and harms [7].
• Share results responsibly: Include harms and limitations and avoid overstating surrogate outcomes.

Common Study Protocol Example

Example: Phase 2, randomised, double-blind, placebo-controlled and conducted over 12 to 24 weeks.

• Population: Adults with a defined wasting condition or sarcopenia criteria, stratified by sex and baseline functional status.
• Arms: Placebo versus low dose versus higher dose, or placebo versus one selected dose.
• Primary endpoint: A functional outcome, such as stair climb power, at week 12 or 24.
• Key secondary endpoints: DXA lean mass, grip strength, patient-reported fatigue or quality of life and falls.
• Safety: Hepatic, lipid and endocrine laboratory tests, ECG, AE and SAE monitoring and DSMB reviews at defined intervals.
• Stopping rules: Predefined liver-enzyme thresholds, serious cardiovascular-event triggers and a cluster of unexpected serious adverse events.

Conclusion: Key Safety and Ethics Reminders

• Quality and adulteration risk: Do not rely on consumer-market products. The investigational product must be manufactured and controlled to clinical standards.
• Off-label misuse risk: Consider participant education and monitoring to reduce concurrent anabolic-agent use.
• Clear communication: Consent language should state the product’s investigational status, unknown long-term risks and available alternatives.
• Responsible research conduct: Apply the Australian Code for the Responsible Conduct of Research throughout study design, conduct and reporting [3].

References

1. Therapeutic Goods Administration. Clinical trials involving unapproved therapeutic goods.
2. National Health and Medical Research Council. National Statement on Ethical Conduct in Human Research.
3. National Health and Medical Research Council, Australian Research Council and Universities Australia. Australian Code for the Responsible Conduct of Research.
4. Australian New Zealand Clinical Trials Registry. Trial registration.
5. International Council for Harmonisation. Good Clinical Practice.
6. SPIRIT Statement. Protocol guidance and checklist.
7. CONSORT. Randomised trial reporting guidance.
8. World Anti-Doping Agency. Prohibited List.
9. PubMed. MK-2866, enobosarm, ostarine and GTx-024 literature.
10. PubMed. LGD-4033 and ligandrol literature.
11. PubMed. S-4 and andarine literature.
12. PubMed. RAD140 and testolone literature.
13. PubMed. MK-677 and ibutamoren literature.
14. PubMed. GW0742 and PPAR literature.