Regenxbio Likely to Add Dimension’s DTX201 for Hemophilia A to Its Pipeline

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by Alice Melão |

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Dimension Therapeutics may soon become a wholly owned subsidiary of Regenxbio, following the terms of an agreement between the two companies. The merger agreement, if finalized, will add Dimension’s investigational drug candidates being developed to Regenxbio’s pipeline, including DTX201 for the treatment of hemophilia A.

DTX201 was being developed based on Regenxbio’s proprietary NAV technology platform and its adeno-associated virus (AAV) delivery vectors, under a previous collaborative agreement between the two companies.

DTX201 was designed to deliver a copy of the Factor VIII (FVIII) gene to liver cells, promoting its sustained expression to potentially overcome its deficit in hemophilia A patients.

Preliminary results presented during the ASGCT 2016 and EHA 2016 annual meetings from a collaboration with researchers at the University of Pennsylvania showed that DTX201 was able to sustain FVIII expression for long time periods when administrated to macaques and mice, with reduced FVIII inhibitors activation.

Partnered with Bayer, Dimension was conducting investigational new drug (IND)-enabling studies for DTX201. This development program is expected to continue under Regenxbio, which expects to file an IND application to the U.S. Food and Administration (FDA) in early 2018, bringing the treatment into clinical testing.

The proposed acquisition has been approved by the board of directors of both companies, but shareholder approval and other “customary” issues still need to be decided, Regenxbio states in a company a press release.

But at least one other company,  Ultragenyx Pharmaceuticals, is also interested in Dimension and late Monday filed a counterproposal, offering a potentially more attractive per-share stock price.

Regenxbio, however, expresses confidence that its proposal will succeed.

“This acquisition confirms REGENXBIO’s leadership in the field of AAV gene therapy and expands our pipeline in metabolic diseases using NAV technology with a clinical asset and several preclinical assets,” said Kenneth T. Mills, president and CEO of Regenxbio.

“REGENXBIO has the resources and expertise to be successful in advancing a portfolio of gene therapies for inherited metabolic diseases targeting the liver.”

Regenxbio will also add to its pipeline two lead product candidates, DTX301 for the treatment of ornithine transcarbamylase (OTC) deficiency, and DTX401 for the treatment of glycogen storage disease type Ia (GSDIa).

DTX301 is currently under an active investigational new drug (IND) application for a Phase 1/2 clinical trial. An IND application for DTX401 is expected to be filed in early 2018.

In April 2017, Dimension announced the termination of its gene therapy program for Hemophilia B, DTX101. This decision was based on Phase 1/2 clinical trial (NCT02618915) results that failed to meet the company’s expectations.

“The acquisition of Dimension is another meaningful step in building a robust clinical pipeline of gene therapy product candidates with the goal of improving treatment options for patients and families in many diseases,” said Annalisa Jenkins, CEO of Dimension.

“I am proud of the accomplishments of the Dimension team and of our partners in the research and clinical communities, who together have made significant contributions to the progress of AAV technologies and the advancement of new therapeutic candidates for devastating rare and metabolic diseases associated with the liver,” she added.