Benitec Hoping to Start OPMD Gene Therapy Trial in US, EU Next Year

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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Benitec Biopharma is taking steps to get the needed regulatory clearances to start clinical testing in Europe and the U.S. of BB-301, its experimental gene therapy for oculopharyngeal muscular dystrophy or OPMD, a type of the genetic disease that typically first affects the eyelids and the throat.

The company said it is planning to launch a Phase 1b/2a clinical trial of BB-301 next year.

The announcement follows a successful scientific advice meeting with the National Agency for the Safety of Medicines and Health Products, in France, in the first half of 2021.

“The design of the … study was viewed as appropriate to support first-in-human testing of BB-301,” Benitec said in a press release, also noting that the company has been granted a meeting with the U.S. Food and Drug Administration for later this year.

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BB-301 has been granted orphan drug designation in both the U.S. and the EU.

After doing initial preclinical studies in mouse models, Benitec conducted a study in beagle dogs to determine whether the gene therapy can effectively be delivered by an injection into the muscle at specific sites in the pharynx — the top part of the throat, right behind the mouth — using an open surgical procedure.

The results, released earlier this year, were positive, demonstrating that the gene therapy could effectively get into cells of the pharynx. Benitec then had a meeting with French regulatory agency, officially called the L’Agence nationale de sécurité du médicament et des produits de santé.

At the meeting, the agency confirmed that the preclinical studies so far are adequate to support additional testing of BB-301’s biodistribution and toxicology — that is, where it goes in the body, and whether it causes any damage to tissues.

Once the biodistribution and toxicology study is complete, the preclinical data “are sufficient to inform the choice of the BB-301 drug doses” used in the upcoming clinical trial, according to Benitec.

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The agency also confirmed the adequacy of Benitec’s manufacturing plan for making the BB-301 to be used in upcoming trials, as well as the proposed design of the company’s planned clinical trial.

“The design of the Phase 1b/2a clinical trial can support the evaluation of BB-301 safety and clinical efficacy in key populations of OPMD patients,” the company stated. Benitec noted that details of the trial’s design will be announced in the future.

OPMD is caused by mutations in the gene PABPN1, resulting in the production of an abnormal protein that clumps in muscle cells, leading to muscle weakness. Symptoms typically start in middle age — anywhere from ages 40 to 60 — and include droopy eyelids and difficulty swallowing.

BB-301 uses a DNA-directed RNA interference (ddRNAi) platform to address OPMD’s underlying genetic defect. Simply put, this involves reducing the activity of the mutated gene while simultaneously delivering a non-mutated version of the gene to cells as a “replacement.”