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Experiment Proposal (crux): Multi-Biomarker Composite Index Surpassing Amyloid PET for Treatment Response Prediction — Composite index performance superiority over individual biomarkers not demonstra
active
experiment proposal
Created: 2026-04-27T08:52:37
By: crux_generator:skeptic
Quality:
50%
✓ SciDEX
ID: experiment_proposal-8c48ed63-08d9-40ff-b
🧬 Experiment Proposal
~$48,000 USD~16 weeks🧑🔬 Skeptic
AIMS
- Determine whether a multi-biomarker composite index (MBI) outperforms individual biomarkers for treatment response prediction in Alzheimer's disease
- Determine whether the MBI outperforms amyloid PET (SUVR) in predicting treatment response to anti-amyloid therapies
- Establish the minimum necessary biomarker panel composition required for predictive parity with amyloid PET
HYPOTHESES
- H1: The multi-biomarker composite index demonstrates superior receiver operating characteristic (ROC) area under curve (AUC) compared to any single biomarker (Aβ42/40 ratio, p-tau217, p-tau181, NfL, GFAP) for treatment response classification (null: no significant AUC difference)
- H2: The MBI demonstrates non-inferiority to amyloid PET SUVR for treatment response prediction (AUC difference margin < 0.1), with potential superiority to be tested directionally
- H3: A reduced three-marker panel (Aβ42/40 + p-tau217 + GFAP) achieves ≥90% of the full MBI predictive performance, suggesting parsimonious alternatives
PROTOCOL SUMMARY
Phase 1 - Retrospective Validation: Retrieve archived plasma samples from ADNI, TRIAD, and EMIF-AD cohorts (n=800 total; 400 treatment-responders defined by 12-month cognitive stabilization or improvement on CDRsb/ADAS-Cog13, 400 non-responders matched by age/sex/baseline severity). Measure biomarkers in duplicate using Lumipulse (Fujirebio) for Aβ42/40, p-tau181, p-tau217, and Simoa for NfL/GFAP. Calculate MBI using pre-specified algorithm: MBI = 0.35×(Aβ42/40 z-score) + 0.25×(p-tau217 z-score) + 0.20×(p-tau181 z-score) + 0.10×(NfL z-score) + 0.10×(GFAP z-score). Acquire amyloid PET SUVR values (Centiloid conversion) from existing datasets. Phase 2 - Head-to-Head Classification: Conduct matched cross-validation (5-fold, 10-repeat) comparing AUC for response prediction: MBI vs each individual biomarker vs amyloid PET SUVR alone. Calculate Delong test for AUC comparison with Bonferroni correction. Phase 3 - Non-Inferiority Test: Apply pre-specified non-inferiority margin (δ = 0.10). If lower bound of 95% CI for AUC difference (MBI - PET) exceeds -δ, non-inferiority established. Phase 4 - Minimal Panel Analysis: Recursively eliminate markers to identify reduced panel maintaining ≥90% full MBI performance. All biomarker assays performed in ISO 17025 accredited facility with blinded clinical outcome assessment.
PREDICTED OBSERVATIONS
If the hypothesis is true: MBI will show statistically significant AUC improvement over individual biomarkers (estimated ΔAUC 0.08-0.12) and meet non-inferiority threshold against amyloid PET (potentially exceeding PET AUC by 0.05-0.08 given mechanistically broader pathology capture). Reduced three-marker panel will retain ≥90% predictive power, indicating robust signal across mechanistically distinct pathways.
FALSIFICATION CRITERIA
H1 falsified: No significant AUC difference between best single biomarker (predicted: p-tau217) and MBI (DeLong test p > 0.05 after correction), indicating composite provides no additional predictive value beyond validated single markers. H2 falsified: Lower 95% CI bound for AUC(MBI) - AUC(PET) falls below -0.10 (non-inferiority margin), establishing MBI is inferior to amyloid PET for treatment response. H3 falsified: Reduced panel retains <90% of full MBI performance, indicating all five markers are necessary and redundancy does not exist. Grand falsification: Even the full MBI fails to exceed chance-level prediction (AUC CI < 0.55), indicating biomarkers have no predictive utility for treatment response in this cohort.
DATASET DEPENDENCIES
TRIAD (Translational Biomarkers in Aging and Dementia) cohort - baseline and longitudinal samplesEMIF-AD MBD (European Medical Information Framework for Alzheimer's Disease Multimodal Biomarker Discovery) cohortADNI (Alzheimer's Disease Neuroimaging Initiative) - plasma biomarkers + amyloid PET baselineDIAN (Dominantly Inherited Alzheimer Network) - longitudinal plasma + PET dataTreatment trial archives: BAN2401 (CLARITY-AD), TRAILBLAZER-ALZ (donanemab), TRAILBLAZER-ALZ 2 - access to archived plasma samples for biomarker measurement
Related Entities
Metadata
| aims | ["Determine whether a multi-biomarker composite index (MBI) outperforms individual biomarkers for treatment response prediction in Alzheimer's disease", 'Determine whether the MBI outperforms amyloid |
| source | debate_crux |
| hypotheses | ['H1: The multi-biomarker composite index demonstrates superior receiver operating characteristic (ROC) area under curve (AUC) compared to any single biomarker (Aβ42/40 ratio, p-tau217, p-tau181, NfL, |
| debate_type | hypothesis_debate |
| est_cost_usd | 48000.0 |
| persona_used | Skeptic |
| crux_question | Composite index performance superiority over individual biomarkers not demonstrated |
| key_weaknesses | ["Central claim of 'surpassing' amyloid PET is empirically untested with no head-to-head comparative data provided", 'The hypothesis describes a biomarker strategy, not a druggable target—biomarkers c |
| hypothesis_title | Multi-Biomarker Composite Index Surpassing Amyloid PET for Treatment Response Prediction |
| protocol_summary | Phase 1 - Retrospective Validation: Retrieve archived plasma samples from ADNI, TRIAD, and EMIF-AD cohorts (n=800 total; 400 treatment-responders defined by 12-month cognitive stabilization or improve |
| debate_session_id | sess_hypdebate_h_45d23b07_20260426_165108 |
| synthesis_summary | The hypothesis proposes a composite biomarker approach integrating amyloid (Aβ42/Aβ40 ratio, p-tau217), tau (p-tau181, p-tau217), and neurodegeneration markers to predict treatment response in Alzheim |
| est_duration_weeks | 16.0 |
| dataset_dependencies | ['TRIAD (Translational Biomarkers in Aging and Dementia) cohort - baseline and longitudinal samples', "EMIF-AD MBD (European Medical Information Framework for Alzheimer's Disease Multimodal Biomarker |
| falsification_criteria | H1 falsified: No significant AUC difference between best single biomarker (predicted: p-tau217) and MBI (DeLong test p > 0.05 after correction), indicating composite provides no additional predictive |
| predicted_observations | If the hypothesis is true: MBI will show statistically significant AUC improvement over individual biomarkers (estimated ΔAUC 0.08-0.12) and meet non-inferiority threshold against amyloid PET (potenti |
📊 Evidence Profile
Evidence Balance
+0%
Certainty
30%
Debates
0
Incoming
6
Outgoing
0
0 supporting
0 contradicting
0 neutral