Recruiting PNH trials faster – how Home Trial Support transforms rare disease research

In rare disease clinical development, patient scarcity and geographical dispersion create a persistent challenge: sponsors open dozens of clinical trial sites that each manage to recruit only one or two patients over several years. But what if investigator sites could dramatically expand their geographical reach without adding burden to site personnel?

New portfolio modeling across MRN’s haematology and complement-mediated trial experience reveals that integrating Home Trial Support (HTS) fundamentally transforms rare disease trial mechanics. In Paroxysmal Nocturnal Haemoglobinuria (PNH) – the commonest of these rare complement conditions – adding HTS cuts overall recruitment time by nearly a quarter, reduces the required site footprint by approximately 15 centres, and enables up to 70% of protocol visits to take place comfortably in the patient’s home.

Why rare disease recruitment stalls – and how HTS solves it

Traditional trial setups in conditions like PNH concentrate a handful of patients per million across specialized medical centres. Sites typically see recruitment rates averaging 0.20 patients per site per month (PPM) in PNH, and as low as 0.02 to 0.06 PPM in ultra-rare hereditary conditions. Sponsors are forced to open large site networks, driving up study activation and operational costs.

Home Trial Support does not replace the investigator site; rather, it acts as an additive multiplier. By deploying dedicated research nurses to carry out protocol assessments and administer investigational products directly in the patient’s home, HTS expands each site’s catchment area. Remote and travel-constrained patients who previously could not participate can now enrol under the oversight of an established site.

“HTS is additive to a site’s recruitment capacity, not a substitute. By removing geographic barriers for distant patients, sites recruit individuals they otherwise could never reach.”

Planning rules for next-generation rare disease protocol design

Based on MRN’s cross-therapeutic delivery data across complement and rare haematology indications, clinical operations teams should incorporate five core principles during early study design:

1. Model HTS as an Additive Contribution: Baseline traditional recruitment at 0.20 PPM for PNH (six-trial benchmark average) and 0.02–0.06 PPM for ultra-rare conditions. Layer HTS on top as an additive recruitment driver rather than a replacement.
2. Shift Non-Fixed Assessments Out of the Clinic: Around 7 in 10 protocol visits across complement-mediated diseases can be safely delivered at home. Reserve clinic visits exclusively for equipment-fixed procedures (e.g., specialised imaging).
3. Match HTS Strategy to Disease Rarity: HTS delivers the largest proportional gains in both timeline speed-up and overall study cost where baseline site recruitment is lowest. The rarer and more dispersed the patient population, the greater the transformational impact.
4. Embed Home Support from Day One: Retrofitting HTS midway through recruitment captures only a fraction of its potential. To maximize site-reduction savings and speed up timelines, HTS must be offered at or before consent, prior to opening unnecessary sites.
5. Utilize Dedicated Third-Party Research Nurses: Keeping the home-visit workload separate from site staff protects site capacity. Third-party nurses are sourced locally near the patient, avoiding site nurse travel burnout and maximising reach.

Impact across indications: PNH, Haemophilia B & Congenital TTP

The operational and financial impact of HTS scales dramatically as indication rarity increases:

A proven track record in rare haematology & complement-mediated trials

MRN brings over a decade of hands-on delivery experience across complex haematological and complement-mediated indications, including PNH, aHUS, congenital TTP, Haemophilia B gene therapy, hereditary angioedema, multiple myeloma, and beta-thalassaemia.

• In a 20-patient, multi-country, Phase 3 congenital TTP trial, MRN research nurses executed over 700 home visits across 9 sites in 5 countries over three years, sustaining long-term participation in an ultra-rare population.
• In a 12-patient PNH programme, MRN delivered nearly 500 home visits across 6 sites in 5 countries under a single global contract.
• Across all complement and haematology indications, MRN nurses have successfully delivered 1,452 specialised protocol visits in the home.