GCC Dravet Syndrome Market Sizing Model

The epidemiology method sizes the GCC Dravet population from a global prevalence rate of 1:15,700 applied to the region's roughly 12 million paediatric population, implying an estimated 600-800 total patients. The genetic-confirmation method counts differently: SCN1A molecular testing is available at only 5-6 GCC centres (KFSH&RC, AUH, Sidra Medicine among them), and these centres combined account for fewer than 200 molecularly confirmed cases, meaning roughly 70% of the estimated population lacks the genetic documentation specialist Dravet-specific therapy typically requires. That gap is a diagnostic-capacity finding, not a measurement error: testing turnaround runs 4-8 weeks, some centres require pre-test genetic counselling, and many physicians instead treat clinically probable Dravet without ever ordering the test.

A third figure, 200-400 patients, answers a different question again: it is the near-term actionable population modelled in the AXLRx Launch Readiness assessment, capturing patients under active specialist follow-up at GCC paediatric epilepsy centres who are identified, whether through molecular confirmation or a clinically documented Dravet phenotype, as candidates for NPHC exceptional-access evaluation. It sits between the tightest evidentiary tier (fewer than 200 confirmed) and the full epidemiological estimate (600-800), reflecting active specialist engagement rather than either genetic certainty or unascertained population burden. A pre-launch plan that used only the 600-800 epidemiological total would overstate near-term reach; a plan built only on the fewer-than-200 confirmed count would miss the clinically-identified patients already engaged with specialist centres. The 200-400 actionable tier is the base a near-term launch and NPHC access plan should model against.

Every AXLRx market sizing model triangulates at least two independent methods, epidemiology-based and registry-based, before accepting a patient count, and separates any additional planning-specific tier from the underlying totals rather than presenting it as a competing estimate. This is explicitly a sizing model (static patient count), distinct from a Patient Flow or forecasting model (dynamic revenue/uptake).

Dravet syndrome GCC sizing sources: KFSH&RC, AUH, and Sidra Medicine paediatric epilepsy genetics programme data (2022), GCC child neurology society epidemiology data, the Saudi epilepsy society paediatric registry, and the AXLRx Dravet Syndrome GCC Launch Readiness assessment.