By Sy Mukherjee
February 7, 2019

Greetings, readers.

Gene therapy and gene editing have taken the life sciences by storm in the past few years. We’ve seen the approvals of treatments that re-engineer patients’ cells to fight cancer and shocking claims of gene-edited babies abroad; dozens of biotechs continue to experiment with technologies such as CRISPR and “gene silencing,” techniques which could (theoretically) curb a multitude of diseases, from rare inherited disorders to cancers.

But the sector had a dour day as a pair of early-stage studies came up short. Sangamo Therapeutics stock sank 31% in Thursday trading on interim data for gene-editing techniques to treat the rare disorders MPS I and II.

It’s a particularly unfortunate setback since the news wasn’t all bad. The underlying technology actually did appear to work on some level – just not nearly enough to produce a meaningful clinical benefit for patients at this point, according to CEO Sandy Macrae.

In another part of the sector, Solid Biosciences’ gene therapy treatment for the devastating movement disorder Duchenne muscular dystrophy (DMD) also appeared to fall short, absolutely devastating the small biotech’s stock, which fell 68%.

Again, these are early-stage results. But it goes to show just how fraught the drug making business can be, even in an era of pioneering treatments.

Read on for the day’s news.

Sy Mukherjee
@the_sy_guy
sayak.mukherjee@fortune.com

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