RECIST Criteria in Tigilanol Tiglate Trials: How Tumour Response Is Measured in EBC-46 Studies

When clinical trials of an oncology agent report tumour responses, the underlying measurement framework matters. The Response Evaluation Criteria In Solid Tumours (RECIST) is the standard most published trials use, with version 1.1 the current reference. For tigilanol tiglate (EBC-46), an intratumoural agent rather than a systemic chemotherapy, RECIST application requires some adaptation — and understanding those adaptations helps readers interpret published response rates accurately.

What RECIST measures

RECIST 1.1 categorises tumour responses based on changes in the sum of the longest diameters of target lesions, measured by imaging. Complete Response (CR) requires disappearance of all target lesions; Partial Response (PR) requires a 30 per cent decrease in the sum of longest diameters; Progressive Disease (PD) is defined as a 20 per cent increase or new lesions; and Stable Disease (SD) is everything in between. The framework was developed for systemic agents in solid tumours and works well when measurements are taken at fixed intervals using consistent imaging modalities.

Why intratumoural agents need adaptation

An intratumoural injection of tigilanol tiglate produces a treatment effect that is fundamentally local: the injected lesion typically undergoes acute swelling, then necrosis, then resolution over weeks. Standard RECIST timing — assessment at six to eight weeks — captures the resolved state, but misses the immediate post-injection dynamics. The published QBiotics trials and academic reports therefore use modified response assessment that combines RECIST-style measurements with clinical photography, palpation, and where appropriate biopsy at defined timepoints.

How injected lesions are scored

In the published Phase I/II human and veterinary studies, response assessment for the injected lesion typically uses both RECIST 1.1 measurements (where the lesion is amenable to imaging) and a composite local response score that captures necrosis, ulceration, healing, and ultimately scarring. Lesions that fully heal to a flat scar with no clinical or imaging evidence of residual tumour are scored as complete responses; partial responses describe lesions that shrink substantially but retain some viable tissue. Distant, non-injected lesions are scored separately under standard RECIST.

Reported response rates and what they mean

The pivotal QBiotics veterinary work — the basis for FDA approval of Stelfonta in canine mast cell tumours — reported approximately 75 per cent complete responses for treated lesions at four weeks, with sustained responses at the longer-term follow-up. The early human Phase I/II data for tigilanol tiglate report similarly high local response rates for injected lesions, although the patient cohorts are small and the indications are restricted to specific tumour types accessible to direct injection. The FDA approval documentation for Stelfonta contains the full pivotal study summary, including response criteria.

Limitations of RECIST in this context

RECIST does not capture quality-of-life outcomes, durability of response beyond the assessment window, or systemic immune effects. For a local treatment like tigilanol tiglate, the most clinically meaningful endpoints often go beyond tumour size — wound healing time, local recurrence rates at one and two years, and patient-reported pain or function scores. Published trials therefore typically include RECIST as one element of a broader endpoint package rather than the sole readout. Readers comparing trial reports should look for the timepoint at which RECIST was applied and whether composite local response scoring was also reported.

Distinction from supplement claims

All RECIST-based response data in the EBC-46 literature comes from pharmaceutical studies of intratumoural tigilanol tiglate. Oral blushwood berry extract supplements have not been evaluated in RECIST-based trials, and the supplement category does not require such evidence under FDA dietary supplement law. Brands selling blushwood berry extract — such as Blushwood Health — do not make tumour-response claims and operate under structure/function statement rules. Conflating pharmaceutical RECIST data with supplement performance is a category error and a recurring source of confusion in consumer-facing material.

Reading published response data

When evaluating any tigilanol tiglate response data, useful questions include: what version of RECIST was used; were responses assessed by independent radiology review; what was the assessment timepoint; was a composite local response score also reported; and what was the duration of follow-up? The strongest published data — the Stelfonta pivotal study and the QBiotics human Phase I/II reports — address each of these explicitly. Less rigorous secondary sources sometimes quote response rates without specifying the underlying criteria, which makes cross-study comparison unreliable.

Related articles

long-term follow-up and recurrence ratesbiomarker monitoring in EBC-46 clinical trials

Citations

1. RECIST 1.1 — EORTC RECIST Working Group.

2. FDA — Stelfonta (tigilanol tiglate) approval for canine mast cell tumours.

3. QBiotics Group — Tigilanol Tiglate Clinical Programme.

Statements about dietary supplements have not been evaluated by the Food and Drug Administration. Any blushwood-berry supplement is not intended to diagnose, treat, cure, or prevent any disease.