HAYWARD, Calif. — Benitec Biopharma Inc. (NASDAQ: BNTC) (“Benitec” or “Company”), a clinical-stage, gene therapy-focused, biotechnology company developing novel genetic medicines based on its proprietary “Silence and Replace” DNA-directed RNA interference (“ddRNAi”) platform, today announced promising interim clinical results from the BB-301 Phase 1b/2a first-in-human study (NCT06185673) evaluating low dose and high dose BB-301 treatment for Oculopharyngeal Muscular Dystrophy (OPMD) with moderate dysphagia. Interim and long-term clinical results for patients enrolled into Cohort 1 (low dose BB-301 ), and interim clinical results for the first patient enrolled into Cohort 2 (high dose BB-301) in the ongoing clinical trial will be presented as a late-breaking poster presentation at the Muscular Dystrophy Association (MDA) Clinical and Scientific Conference, in Orlando, Florida on March 9, 2026.
“We are strongly encouraged by the 100% response rate and the depth and durability of the responses that have been observed for all patients treated with BB-301 to date,” said Jerel A. Banks, M.D., Ph.D., Executive Chairman and Chief Executive Officer of Benitec. “We are incredibly excited to share these interim clinical results which demonstrate positive, clinically meaningful improvements across the most critical radiographic, functional, and patient-reported assessments of swallowing function. With no currently approved treatments for OPMD patients, the results presented today represent an important step towards the management of the unmet medical need that exists in the OPMD community. We remain committed to advancing the BB-301 program, and we are deeply grateful to the patients, their families, and our investigators whose unyielding commitment continues to make this progress possible.”
BB-301 Phase 1b/2a Clinical Treatment Study Background:
The BB-301 Phase 1b/2a clinical study (NCT06185673) is an open-label, dose escalation study evaluating the safety and clinical activity of intramuscular doses of BB-301 to treat moderate dysphagia in patients with OPMD.
The following parameters represent the core assessments of BB-301 efficacy for each study participant: Sydney Swallow Questionnaire (SSQ), pharyngeal area at maximum constriction (PhAMPC), total pharyngeal residue (TPR) and normalized residue ratio scale-valleculae (NRRSv). The SSQ is a validated 17-item patient-reported outcome instrument that assesses the total dysphagic symptom burden experienced by a patient. The PhAMPC is assessed by videofluoroscopic swallowing studies (VFSS) and serves as a surrogate for the functional capacity of the pharyngeal constrictor muscles during the swallowing cycle. The TPR is assessed by VFSS and represents the quantity of food and liquid material (residue) remaining in the throat upon completion of a swallow (post-swallow residue). The NRRSv is assessed by VFSS and represents the quantity of food and liquid material (residue) remaining in the vallecular region of the throat upon completion of a swallow (post-swallow residue).
Key interim clinical study results to be presented at the 2026 MDA Clinical & Scientific Conference include:
Interim Clinical Results for High Dose BB-301 (Cohort 2):
- High dose BB-301 is being evaluated for the potential to facilitate more rapid clinical improvements and/or greater magnitudes of clinical improvements across the core functional, anatomical, and symptom-focused elements of the dysphagic symptom burden experienced by OPMD patients
- Patient B (Cohort 2, high dose BB-301) safely received the high dose of BB-301 with no treatment-related SAEs
- Patient B (Cohort 2, high dose BB-301) and Patient A (Cohort 1, low dose BB-301) had comparable baseline functional, anatomical, and symptom-focused deficits prior to the administration of BB-301
- When comparing 3-month post-BB-301-treatment clinical results for Patient A and Patient B, Patient B experienced a significant improvement in depth of response to high dose BB-301
Patient B, the first OPMD Patient treated with high dose BB-301, experienced an extraordinarily robust dose-response at an early interim follow-up time-point, indicating the continued potential for BB-301 to achieve disease-modifying outcomes for OPMD patients with dysphagia.
When comparing the interim clinical results for the low dose BB-301 treatment and the high dose BB-301 treatment at the 3-month post-treatment time-point in Patients with comparable pre-treatment baseline deficits, the high dose BB-301 treatment demonstrated significantly improved results across all radiographic and patient-reported assessments employed in the BB-301 Phase 1b/2a Clinical Treatment Study:
- Significantly differentiated levels of dysphagic symptom burden reduction were observed, with a ~7% reduction in total dysphagic symptom burden (SSQ) achieved with low dose BB-301 as compared to a ~68% reduction in SSQ achieved with high dose BB-301
- Significantly differentiated levels of throat closure were observed, with an ~8% improvement in throat closure (PhAMPC) achieved with low dose BB-301 as compared to a ~19% improvement in PhAMPC achieved with high dose BB-301
- Significantly differentiated levels of overall throat emptying were observed, with a ~6% worsening in overall throat emptying (TPR) observed with low dose BB-301 as compared to a ~44% improvement in TPR achieved with high dose BB-301
- Significantly differentiated levels of throat emptying from the vallecular region were observed, with a ~3% improvement in throat emptying from the vallecular region (NRRSv) achieved with low dose BB-301 as compared to a ~57% improvement in NRRSv with high dose BB-301
Interim Clinical Results for Low Dose BB-301 (Cohort 1):
- All Study Completers in Cohort 1 (low dose BB-301) are formal Responders to BB-301
- Completers are Patients that have reached the 12-month post-BB-301-treatment assessment time-point in the BB-301 Phase 1b/2a Clinical Treatment Study
- Long-term efficacy trends for low dose BB-301 at 24-months post BB-301 treatment continue to demonstrate robust disease-modifying outcomes for throat closure, throat emptying, and total dysphagic symptom burden
Late-Breaking Poster Presentation
An interim clinical study update for the Phase 1b/2a Clinical Treatment Study of BB-301 in OPMD subjects with moderate dysphagia will be provided in a late-breaking poster presentation, (poster number 501 LB) entitled “Durable Responses to Low Dose BB-301 in Oculopharyngeal Muscular Dystrophy at 12- and 24-months and Improved Depth of Response to High Dose BB-301” during poster sessions from 10:15-10:45 am, 12:00-1:30 pm, 3:30-4:00 pm and 6:00-8:00 pm Eastern Time on March 9th in the Exhibit Hall at the 2026 Muscular Dystrophy Association Clinical & Scientific Conference. The poster is available on the Benitec website, and a link to the poster is found here.
About OPMD
There are currently no approved therapies for OPMD, a rare autosomal-dominant degenerative muscle disorder, that impacts nearly 15,000 patients in North America, Europe and Isreal. OPMD is caused by a mutation in the poly(A)-binding protein nuclear 1 (PABPN1) gene; PABPN1 is a ubiquitous protein that controls the length of mRNA poly(A) tails, mRNA export from the nucleus and alternative poly(A) site usage. OPMD is a debilitating progressive disease that weakens the pharyngeal muscles, causing severe swallowing difficulties (dysphagia).1 Progressive dysphagia impacts 97% of OPMD patients and is a severe, life-threatening complication of OPMD which can lead to chronic choking, malnutrition, aspiration pneumonia and death.
About BB-301
BB-301 is a novel, modified AAV9 capsid expressing a unique, single bifunctional construct promoting co-expression of both codon-optimized Poly-A Binding Protein Nuclear-1 (PABPN1) and two small inhibitory RNAs (siRNAs) against mutant PABPN1 (the causative gene for OPMD). The two siRNAs are modeled into microRNA backbones to silence expression of faulty mutant PABPN1, while allowing expression of the codon-optimized PABPN1 to replace the mutant with a functional version of the protein. We believe the silence and replace mechanism of BB-301 is uniquely positioned for the treatment of OPMD by halting mutant PABPN1 expression while providing a functional replacement protein. BB-301 has received Orphan Drug Designation from the EMA and Orphan Drug and Fast Track Designations from the FDA.
About Benitec Biopharma Inc.
Benitec Biopharma Inc. (“Benitec” or the “Company”) is a clinical-stage biotechnology company focused on the advancement of novel genetic medicines with headquarters in Hayward, California. The proprietary “Silence and Replace” DNA-directed RNA interference platform combines RNA interference, or RNAi, with gene therapy to create medicines that simultaneously facilitate sustained silencing of disease-causing genes and concomitant delivery of wildtype replacement genes following a single administration of the therapeutic construct. The Company is developing Silence and Replace-based therapeutics for chronic and life-threatening human conditions including Oculopharyngeal Muscular Dystrophy (OPMD). A comprehensive overview of the Company can be found on Benitec’s website at www.benitec.com.
Reference:
- https://www.mayoclinic.org/diseases-conditions/dysphagia/symptoms-causes/syc-20372028
Media Contact
Audra Friis
Sam Brown Healthcare Communications
(917) 519-9577
[email protected]
Investor Relations Contact:
LifeSci Advisors, LLC
(917) 734-7387
[email protected]