Vertex Pharmaceuticals anticipates a “milestone-rich period” ahead, but there are updates regarding two of its candidates. The biotech has decided to discontinue its alpha-1 antitrypsin deficiency (AATD) therapy, known as VX-864, due to reports of non-serious rash events in some patients, as disclosed in its third-quarter earnings call.
AATD is a condition in which patients produce abnormal forms of the AAT protein, leading to the accumulation of misfolded proteins in the liver, resulting in liver and lung diseases. VX-864, a “corrector molecule,” aimed to prevent misfolding of AAT and increase plasma AAT levels. Vertex had previously halted the therapy’s progression into late-stage development in 2021, as its effect was deemed unlikely to translate into significant clinical benefit.
Despite this decision, Vertex initiated a new phase 2 study in the following year to assess the therapy’s impact on polymer clearance from the liver over a more extended period. However, the study has now been terminated due to the reports of rash.
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Vertex will continue to enroll and dose healthy volunteers in its other AAT correctors, VX-634 and VX-668, which represent the “next wave” of investigational therapies with improved potency and drug-like properties.
Additionally, Vertex’s plans to enter the Duchenne muscular dystrophy (DMD) space have slowed. The company was exploring whether CRISPR/Cas9 gene editing technology could be used to treat DMD by delivering it to muscle cells with a virus, AAV9. However, Vertex has decided to conduct additional in vitro and animal studies on the delivery system before proceeding with human testing. The company is also designing next-generation delivery systems for in vivo gene editing in DMD based on the lessons learned from its first-generation vectors.
Despite these developments, Vertex is eagerly awaiting the FDA’s decision on exa-cel, a CRISPR gene-editing-based therapy developed in partnership with CRISPR Therapeutics for sickle cell disease, with expectations for a positive verdict on December 8. If approved, it will mark the first-ever CRISPR gene-editing-based therapy to reach the market.
