Tumour-Type Stratification in Tigilanol Tiglate Trials: How Cohorts Are Built

When a clinical trial reports an overall response rate, that single percentage usually masks a great deal of heterogeneity beneath the surface. Different tumour types respond differently. Different anatomical sites have different injection logistics. Different molecular subtypes have different baseline biology. Understanding how a trial stratifies its cohort — that is, how it divides participants into groups for separate analysis — is essential to interpreting what the headline numbers actually mean. This article walks through how stratification has shaped the published tigilanol tiglate trial programme, both in companion-animal oncology and in the human Phase I/II programme.

What stratification is, and why it matters

Stratification is the practice of dividing a clinical trial's patient population into pre-specified subgroups before analysis, so that response rates and safety profiles can be reported separately for each group. Trials may stratify by tumour type, tumour stage, anatomical location, prior therapy, performance status, or molecular markers. The reason is straightforward: a 40% overall response rate looks very different if it is driven entirely by one subset of patients responding at 80% while another subset shows no response at all.

Modern oncology trial design relies heavily on pre-specified stratification, and frameworks like FDA cancer trial eligibility guidance encourage transparent reporting of subgroup data. For an intratumoural therapy like tigilanol tiglate, where the local microenvironment varies enormously by tumour type, the case for stratified analysis is even stronger.

Stratification in the canine Stelfonta programme

The clearest published example of stratification for tigilanol tiglate is the veterinary programme that produced Stelfonta, the FDA-approved injectable for canine mast cell tumours. The pivotal trial was deliberately built around a single tumour type — non-metastatic mast cell tumours — and within that, results were further analysed by tumour grade and anatomical site (cutaneous vs. subcutaneous). The single-tumour-type design produced cleaner efficacy data and informed the FDA's eventual approval, summarised on the Stelfonta approval announcement.

Stratification in the human Phase I/II programme

Human trials of tigilanol tiglate have taken a different approach: rather than narrowing to one tumour type, the early-phase programme has enrolled patients across several solid-tumour categories — including head-and-neck, melanoma, breast, and other surface-accessible lesions — to characterise the compound's behaviour broadly before designing pivotal studies in specific indications. This is a standard early-phase approach: cast a wide net, generate signal-finding data, then design Phase III in the indications with the strongest signal.

The trade-off is statistical: with multiple tumour types in a single Phase I cohort, individual subgroup numbers are small, and confidence intervals around per-tumour-type response rates are wide. Readers of trial publications should look for tables that report responses by tumour type, the number of patients in each group, and confidence intervals or ranges. A single 'overall response rate' across mixed tumour types is the least useful summary statistic in such a study.

Why anatomical site also matters

Beyond tumour type, anatomical site shapes injection logistics. Surface lesions on the trunk or limbs are easy to inject precisely. Lesions on the head and neck — particularly near nerves or major vessels — require careful planning. Lesions in the oral cavity introduce different swelling and aspiration considerations. Trial protocols typically stratify (or restrict) by site to keep the injection technique consistent and the safety profile interpretable. When response rates differ substantially across anatomical strata, the explanation is often technical (how reproducible the injection was) rather than purely biological.

Reading trial publications carefully

When reading a published tigilanol tiglate trial — or any oncology trial — a useful checklist is: how was the cohort stratified, were subgroup analyses pre-specified or post-hoc, what were the per-stratum response rates and confidence intervals, and how does the response definition (RECIST, modified RECIST, or volumetric) map across strata. Companion articles in this series cover RECIST criteria in tigilanol tiglate trials and the trial adverse-event profile by cohort.

What this means for supplement consumers

It is worth keeping the framing straight. The pharmaceutical trial programme studies an injectable formulation of pure tigilanol tiglate (Stelfonta in animals; an investigational human product). It is not the same as a dietary blushwood berry extract supplement. Reputable supplement brands such as Blushwood Health market their 10:1 whole-seed extract as a botanical supplement under DSHEA — not intended to diagnose, treat, cure or prevent any disease. The clinical-trial literature is informative background for the supplement category, but does not constitute a claim about supplement performance.

Citations

1. FDA — Stelfonta (tigilanol tiglate) approval announcement, 2020.

2. QBiotics Group — Tigilanol Tiglate clinical programme overview, accessed 2026.

3. FDA — Cancer Clinical Trial Eligibility Criteria guidance, 2020.

Related Articles

More on trial design and outcomes: Long-term follow-up of tigilanol tiglate trials, and Biomarker monitoring in EBC-46 clinical trials.