Regenxbio trials halted after brain tumor found in patient

The FDA paused trials for two experimental gene therapies from Regenxbio after one child developed a brain tumor, the company said this morning.

The two treatments are designed to replace the genes broken in Hurler and Hunter syndromes, which are devastating and fatal rare diseases that cause a string of cognitive, cardiac, and other impairments.

Both therapies rely on injecting patients with adeno-associated viruses (AAVs), a class of widely used gene therapy viruses, to carry replacement genes into the brains of patients. There have long been concerns, based on some early mouse studies, that AAVs could potentially drive cancers by slipping parts of themselves into the genome. But no such cases have been documented in humans after many trials and multiple approved products.

In a statement, Regenxbio objected strenuously to the FDA decision.

exclusive

New ARCH-backed startup to study a CAR-T for glioblastoma

A new startup, Altido Bio, is trying to commercialize a CAR-T cell therapy developed at Massachusetts General Hospital for glioblastoma, a nearly always fatal brain tumor.

It was co-founded by Nick Leschly, the former CEO of Bluebird Bio, and it recently closed a $12.5 million seed round from ARCH Venture.

Data from the CAR-T treatment are still early, but promising. All of the first three patients in a trial saw their tumors immediately shrink significantly. While two patients soon relapsed and ultimately died, one remains alive today, more than 2.5 years after treatment.

policy

Medicare announces new drugs up for negotiation

The Trump administration yesterday disclosed the next 15 drugs subject to Medicare price negotiation, including, for the first time, physician-administered treatments that are covered under Part B.

The Trump administration in the past has downplayed the negotiation program, which was a signature achievement of the Biden administration. But yesterday, CMS Administrator Mehmet Oz touted the new list as an example of the agency “taking strong action to target the most expensive drugs in Medicare.”

The list includes cancer drugs like Eli Lilly's Verzenio, as well as an HIV antiretroviral, Gilead's Biktarvy. These drugs are expected to generate big savings for Medicare.

The agency has also selected Botox, made by AbbVie.

innovation

Boston's tech scene seen to wither as talent leaves

Boston entrepreneurs and venture capitalists have said for some time now that the city's tech ecosystem is shrinking, but their concerns have come to a head amid the biotech downturn in recent years and the global boom in AI, The Boston Globe writes.

In 2025, Massachusetts startups raised $16.7 billion in venture capital, a 12% increase from the year before. But other states saw much bigger jumps: California’s total increased 82%, and Texas rose 72%.

Entrepreneurs say it's getting increasingly hard to recruit engineers and other key talent.

“More so than ever, people are just dying to move to New York and SF,” one said, adding that if Boston “is serious about being a serious hub for tech, that’s a problem that needs to get fixed.”

pharma

Lilly expands work on gene therapies for hearing

From my colleague Jason Mast: Eli Lilly will work with startup Seamless Therapeutics to develop gene-editing treatments for hearing loss.

The deal, announced today, builds on Eli Lilly’s work on a gene therapy for OTOF-driven hearing loss, a rare form of the condition that affects about 20 to 50 newborns in the U.S every year. Lilly is racing Regeneron to develop the first treatments for the disease, but it also has ambitions to address other hearing conditions. Its 2022 acquisition of biotech Akouos gave it at least three other preclinical stage programs alongside the OTOF treatment.

Seamless, a roughly 20-person startup built on research out of Dresden University of Technology in Germany, is one of several startups now focused on turning recombinases — enzymes found in viruses, bacteria, and other branches of life that naturally rearrange DNA — into tools for inserting full genes into DNA. Seamless will design recombinases targeted toward specific hearing loss-related genes and then hand the enzymes off to Lilly. Seamless did not say how much money it is receiving upfront for the collaboration but said it could receive up to $1.1 billion as part of the deal.

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