Directed evolution has become a central pillar in gene therapy. This engineering strategy enables the generation of more efficient variants of genetic editors and delivery vectors. Molecular diversification methods are increasingly sophisticated and are now accelerated by machine learning and AI tools, as showcased at the 29th Annual Meeting of the American Society of Gene and Cell Therapy (ASGCT) held in Boston this week.

How the U.S. FDA might view the latest Duchenne muscular dystrophy (DMD) phase III data with gene therapy RGX-202 became the question for Regenxbio Inc., shares of which  (NASDAQ:RGNX) closed May 14 at $6.25, down 38%, or $3.80, after the results were made public.

Gene therapies rely on vectors to reach the target tissue where they act, such as adeno-associated viruses (AAVs) or lipid nanoparticles (LNPs), among other delivery strategies. Each combination is optimized for a specific cell type and indication, aiming to overcome challenges such as efficacy, specificity and toxicity. On May 13, 2026, two sessions included in the scientific symposia of the 29th Annual Meeting of the American Society of Gene and Cell Therapy (ASGCT), being held in Boston this week, addressed AAV-related toxicities, which have led to fatal cases in clinical trials and remain an area for improvement in approved therapies.

Circular RNA (circRNA) is not a new concept, but it is a novel strategy in the field of gene and cell therapy. While mRNA vaccines have revolutionized medicine, this RNA fragment without free ends surpasses their performance in both efficacy and durability, bringing it to the attention of several pioneering companies. The latest advances in circRNA presented at the 29th Annual Meeting of the American Society of Gene and Cell Therapy (ASGCT) clearly surpass the performance achieved with linear mRNA.

The U.K. Medicines and Healthcare products Regulatory Agency (MHRA) has opened a consultation on changes it is proposing to the legal definition of gene therapies, to reflect the advances in technology and manufacturing over the two decades since the current legislation was drawn up. The aim is to correct the mismatch between regulatory terminology and modern science, which MHRA says “can lead to uncertainty” over how a product is classified and to “inconsistent oversight and potential barriers for developers."

Researchers at Daping Hospital in China have reported that liver-targeted delivery of the APOE3-Christchurch (APOE3Ch) variant, a rare protective form of apolipoprotein E, can indirectly reduce brain pathology, highlighting the therapeutic potential of peripheral approaches to Alzheimer’s disease.

A lower-than-expected increase in dystrophin over baseline in the first and lowest-dose cohort of a phase I/II study of ENTR-601-44 in Duchenne muscular dystrophy (DMD) caused shares of Entrada Therapeutics Inc. to plunge more than 57%, despite the cohort meeting the safety and tolerability primary objective.

Dermatology specialist Leo Pharma A/S is moving into gene therapy with the $50 million acquisition of Replay Holdings LLC, a seed-stage company that is developing high capacity herpes simplex virus vectors to treat rare inherited diseases.

Children and adults with a type of congenital hearing loss now have a free treatment option, with the U.S. FDA’s accelerated approval of Regeneron Pharmaceuticals Inc.’s DB-OTO, an AAV-mediated gene therapy. Branded Otarmeni (lunsotogene parvec), it is cleared specifically for hearing loss caused by variants in the otoferlin gene.

The already-thriving CAR T space took another big stride forward as Eli Lilly and Co. disclosed its plan to acquire Boston-based Kelonia Therapeutics Inc. for as much as $7 billion in cash, including an up-front payment of $3.25 billion, with the rest coming if clinical, regulatory and commercial goals are reached.