The FDA has released a clinical hold on Pfizer and Sangamo’s hemophilia A gene therapy after ordering the companies to stop the trial last year due to concerns about blood clots.

Just a week after Pfizer announced the FDA had unleashed its gene therapy for Duchenne muscular dystrophy from a clinical hold — which was paused as one patient died and others experienced severe side effects  — another one of its gene therapy programs has been given the green light to resume, Pfizer announced during its Q1 earnings call yesterday.

Pfizer’s path at getting a gene therapy to market for patients with Duchenne muscular dystrophy just got a little clearer after a hazy 2021 that saw a clinical hold, an amended late-stage trial and a patient death in an early-stage study.

US regulators will allow the Big Pharma to resume its Phase III study dubbed CIFFREO, Pfizer said Thursday morning, noting it has amended the protocol to assess patients in the hospital for seven days post-administration. The clinical hold lift follows reviews of data and protocol amendments, Pfizer added.

Could this be a comeback year for BioMarin? CEO Jean-Jacques Bienaimé certainly hopes so, as he plans to finally turn the corner on profitability and send the company’s hemophilia gene therapy back to the FDA.

But there are still a few things analysts want to know. Like, what’s going on with the clinical hold on its phenylketonuria gene therapy? And when will the company seek full approval for Voxzogo, its costly achondroplasia drug that got the FDA’s accelerated approval treatment late last year?

As a PhD student at Tufts, Dave Greenwald studied the use of adeno-associated virus (AAV) vectors to deliver gene therapies to people with retinitis pigmentosa, a group of rare genetic eye diseases that causes the retina to break down over time.

While he later left lab life, he now sits at the helm of Apertura Gene Therapy, a biotech that hopes to customize AAV vectors that are used widely in delivering most gene therapies. Apertura announced its launch from stealth with $67 million in Series A financing from Deerfield, where Greenwald is also a vice president of business development.