Gene editing technologies are moving forward in preclinical development with innovative strategies designed to treat diseases at their root and even reverse them. However, many approaches still struggle to reach target cells or tissues – either they fail to arrive, or their efficacy is low. In vivo therapies face numerous challenges, but despite these hurdles, 2025 has marked a year of remarkable progress.

BioWorld’s 2022 end-of-year highlights included a toast to the future – of universal vaccines. Even before SARS-CoV-2 vaccines were developed in record time and saved countless lives during the COVID-19 pandemic, vaccines were a rare bright spot in the fight against infectious diseases. Bacteria are becoming multidrug resistant far faster than new classes of antibiotics are being developed, viral spillover events and vector ranges are increasing, and climate change is helping bacteria and fungi alike breach human thermal protections against infections.

Gene editing can repair mutations that prematurely halt protein synthesis, resulting in incomplete peptides that cause various diseases. However, other approaches achieve the same effect without altering the genome. Startup Alltrna Inc. has developed a strategy based on transfer RNA to bypass the premature stop codons that end early protein translation. The company already has a first clinical candidate that could treat metabolic diseases such as methylmalonemia or phenylketonuria.

The first phase of the U.K. synthetic human genome project has successfully completed, realizing key steps in chromosome synthesis. The work has demonstrated a multistep method for transfecting mouse stem cells with native human chromosomes, where they are stably maintained and can be manipulated to replace native DNA with synthetic DNA. The engineered chromosomes can then be transferred into a human cell in place of the native chromosomes.

A significant share of the risk and heritability of attention-deficit hyperactivity disorder (ADHD) is explained by rare genetic variants. A study led by scientists from Aarhus University in Denmark has uncovered their weight in this condition and identified three variants that will help to better understand their role, the risk of developing it, or its comorbidities, in contrast with the common and more frequent variants associated with ADHD.

Bowhead whales (Balaena mysticetus) live year-round in the icy or near-icy waters of the Arctic and sub-Arctic. Although they migrate with the seasonal cycles of ice formation and melting, they never reach the warmer waters visited by other large marine mammals. Their adaptation to low temperatures may have also enabled them to live longer and avoid cancer, a disease closely linked to aging.

Durable reprogramming of human T cells may now be possible thanks to a new technique based on the CRISPRoff and CRISPRon methodology. Researchers from the Arc Institute, Gladstone Institutes, and the University of California San Francisco have stably silenced or activated genes in this type of immune cell without cutting or altering its DNA, making T cells more resistant, active, and effective against tumors.

While recent advances in gene therapy have offered unprecedented options for patients with hemophilia, new data presented at the 32nd Annual Congress of the European Society of Gene and Cell Therapy (ESGCT), held in Seville Oct. 7-10, revealed persistent concerns regarding the durability of these treatments and their potential liver toxicity.

The transition from complex and costly ex vivo strategies to platforms that enable direct cellular intervention within the body, known as in vivo therapies, is marking a paradigm change in the field of gene and cell therapies by simplifying manufacturing, improving tissue targeting and expanding clinical access to treatments.

As the many challenges facing cell therapies are being addressed, the CAR T field continues to evolve beyond its original design of T cells engineered to target hematological malignancies. During the 32nd Annual Congress of the European Society of Gene and Cell Therapy (ESGCT), held in Seville Oct. 7-10, several studies showed how this technology is being redefined as programmable and adaptable immune cells with expanded functional versatility.