WhelWomen's Health Evidence Lab
WHEL-C-049 · Moderate evidence · 6/10

LETROZOLE for endometriosis

A single systematic review found that letrozole does not improve patient satisfaction or influence symptom recurrence after discontinuation in endometriosis-related pain.

Origin · ApprovedPathway · 505(b)(2) · existing active ingredient, new indicationEvidence arm · Direct researchEvidence supports
How to read thisThe summary above and the proposed mechanism are generated by the model from the sources it ingested, and are written as the model’s reasoning rather than established fact. Any figure quoted from MATRIX is a model-derived association score, not a clinical measurement. How far the published record backs this pair is carried by the score’s own rigor dimension and traced to verbatim sources at the foot of the page.

Hypothesized mechanism

Mechanism not yet characterized in the substrate.

This is the model’s proposed mechanism from the sources on file, not a demonstrated causal pathway. How well the published record supports it is reflected in the rigor and plausibility dimensions of the score, and traced to the verbatim sources at the foot of the page.

How the score was reached, for this pair

The composite score is the sum of five dimensions, each scored 0 to 2 by the model from the evidence on file. Below is the sub-score this specific pair received on each, with what that dimension measures. It scored 6 of 10 overall, a moderate reading, from a direct rated moderate in strength.

The model’s overall reasoning for this pair is the summary at the top of the page, and the mechanism it proposed is in the section above.

Direct research arm · anchors the headline6.0 / 10 · Moderate

Scored for women. Evidence generated in women (female population). (band F1, ×1.00).

Corroboration

The evidence comes from a single systematic review ('Use of aromatase inhibitors to treat endometriosis-related pain symptoms: a systematic review'). Per scoring rules, a single systematic review scores 1 and does not constitute independent replication. No additional independent sources are presented.

1 / 2

Rigor

The source is a systematic review of aromatase inhibitors for endometriosis-related pain, which qualifies as high-rigor design. However, the underlying study quality of pooled trials is not described in the claims.

2 / 2

Specificity

Both the intervention (letrozole, an aromatase inhibitor) and the condition (endometriosis-related pain) are directly named in the claims and source title. The claims specifically discuss letrozole's effects in endometriosis.

2 / 2

Plausibility

The claims report null efficacy findings (no improvement in satisfaction, no influence on recurrence) without describing any mechanism of action. No mechanistic basis is asserted or evidenced in the verified claims.

0 / 2

Consistency

Both claims derive from the same single systematic review and report consistent null findings (no benefit on satisfaction or recurrence). With only one source, directional consistency across independent studies cannot be assessed, so this scores 1.

1 / 2
How the scoring rubric works, in general

Independent reading, reported beside the score

One outside model cross-reference is reported alongside the composite score. It is recorded separately and is not combined into the score.

MATRIX cross-reference Top 1%

Every Cure’smachine-learned treatment-probability model, drawn from a biomedical knowledge graph across roughly 1,800 drugs and 22,000 diseases. It provides a model-based estimate of how plausible a drug-disease link is given the structure of biomedical knowledge, reported alongside the substrate’s own evidence.

For this pair. MATRIX places this pair at Top 1%, with a treat-score of 4.17 (higher is better; across the pairs we cover, scores span about 3.1 to 4.5).

Scored over MATRIX’s own entities, confirming the same drug and disease: CHEBI:6413 (drug) and MONDO:0005133 (disease). Validate against the source: Every Cure’s MATRIX dataset ↗.

More on the MATRIX cross-reference and its provenance

Layers not covered for this pair

Sex-specific pharmacokineticsNone on file

Not covered for this pair. This layer holds documented sex-specific pharmacokinetics for a limited set of drugs, and this compound is not among them yet. A blank here means the drug is not covered by the layer, not that no sex difference exists.

More on the sex-specific pharmacokinetics layer and its sources
Cycle-phase dependenceNone on file

Not covered for this pair. The cycle-phase layer is seeded for the strongest-evidence cases so far (PMDD), and this pair is not among them yet. A blank here means the pair is not covered by the layer, not that the effect was found to be phase-independent.

More on the cycle-phase layer and its sources

Source evidence · what the pipeline ingested

These are the sources the pipeline ingested to detect and score this signal, the published literature the model actually read, each tagged by study type. Where the model combined findings the claim is marked as a synthesis (S), and where the literature disagrees the contradiction is shown (!).

Every source below belongs to this signal’s evidence arm, Direct research. Whel reads each drug-condition pair through four such arms, each held to its own inclusion bar; a signal is surfaced through one of them.

These are the verbatim sources the pipeline surfaced and read; they may not be the full published record for a pair, and the score reflects the strength and agreement of the evidence rather than its volume. The strength of these source types is what the rigor dimension of the score reads off. MATRIX, sex-specific pharmacokinetics, and cycle phase are separate layers the pipeline does not ingest, external cross-references reported beside the score, and they link to their own sources in their sections above.

The primary sources and pipelines this evidence is drawn from