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Regenxbio hit with FDA clinical hold, pushes back gene therapy timelines

The Food and Drug Administration has placed a partial clinical hold on Regenxbio’s leading gene therapy program, causing the biotech to delay the start of a Phase 2b trial in treating patients with the vision-loss disease known as wet AMD.The regulatory hold is not related to the gene therapy product, called RGX-314, but rather with third-party surgical delivery devices, company executives said Tuesday on a third quarter earnings call. Additionally, there have been no adverse events tied to the delivery procedure in an ongoing Phase 1/2 trial that has enrolled 42 patients.Despite those assurances, Regenxbio is internally reviewing its delivery system and “believes there are readily available and suitable alternatives for these third-party devices, if needed.” The biotech now expects starting the Phase 2b trial in the first quarter of 2020 and also plans to hold off on filing an Investigational New Drug application until then for a diabetic retinopathy gene therapy.

While the specific concerns that spurred the clinical hold remain unclear, Regenxbio’s claim the delay isn’t about the product itself, coupled with the absence of related adverse events, suggest “limited impact” to RGX-314’s clinical progression, Chardan analyst Gbola Amusa wrote in a Nov. 6 note to investors.

“We are not aware of any delivery system concerns or complications from the Phase I/IIa study, and we are not aware of any concerns or actions related to these third-party device suppliers or other companies using similar devices in AAV gene therapy surgical delivery systems,” a Regenxbio spokesperson said in a Wednesday statement to BioPharma Dive.

The delay is the FDA’s second clinical hold in recent days in the gene therapy space. Just last week, the FDA partially suspended Novartis’ clinical trial for the gene therapy Zolgensma (onasemnogene abeparvovec), citing inflammation risk through spinal injection.

Amusa also referenced the Novartis hold Wednesday, wondering if a Regenxbio delay on another gene therapy program could be related to those concerns. The biotech said it plans to file an Investigational New Drug application for a Batten disease gene therapy called RGX-181 in the second half of 2020, revising an earlier expectation for a filing by the end of 2019.

“It is unclear to us the extent to which the news on RGX-181’s filing timeline is related to questions on AAV9’s profile post the announced partial clinical hold on AVXS-101 intrathecal trials,” the analyst wrote, referencing Zolgensma by its clinical name.

A company spokesperson denied that event played a role, saying the change in timeline “is not related to the partial clinical hold of the AVXS-101 study.”

Elsewhere, Regenxbio’s third quarter was marked by the company’s first meaningful revenues, coming from royalties on Zolgensma’s sales. The spinal muscular atrophy gene therapy is the first commercial product to use Regenxbio’s technology platform and brought in $9.2 million in third quarter royalties for the biotech.

The company is also set to receive an $80 million milestone payment when Zolgensma reaches $1 billion in cumulative sales.