Thirty years after the earliest gene therapies were tested in patients, the promise of this potentially revolutionary class of medicine is now close to fruition. Gene therapy, or the delivery of nucleic acids to cells in order to address diseases linked to genetic mutations, is at the most significant crossroads in its long journey to market. As the gene therapy market matures from experimental to commercial, the question facing physicians, patients, researchers, and investors is—will gene therapy overcome its bumpy three-decade road to market to be the next game-changing medical innovation?
Until the late 2000s, the signs of success were poor. But years of research have proven that the powerful prospect of altering the underlying causes of disease can be worth waiting for. Eight years later, with evidence piling up in favor of the efficacy of gene therapy, we find ourselves at an inflection. The confluence of technological maturity, investor interest, and regulatory motivation show us that there is true commitment to seeing these agents succeed.
It is increasingly clear that gene therapy technology has rapidly matured since its wild west of the 1990s. Recently, early entrant Spark Therapeutics released successful data in a Phase 1/2 Hemophilia B trial demonstrating that all trial participants reduced the number of infusions needed by a cumulative 99%–an unprecedented result in hemophilia. Spark is simultaneously showing incredible results for a different gene therapy indicated for patients with a specific form of inherited blindness, demonstrating improvement in both overall vision and light sensitivity.
Similarly impressive trials from players big and small are emerging at an increasing clip; indeed, 2017 may witness the first slate of FDA approvals for gene therapies in the United States. However, specific modalities of gene therapy have been plagued by repeated mixed results, marring what would otherwise be a unqualified success story for the industry. In particular—CAR-T agents, which have been studied mostly as drugs targeting blood cancers, have shown alarming signs of patient deaths and neurotoxicity. The most prominent example over the past year has been that of Juno Therapeutics, an upstart manufacturer that arguably kicked off an industry-wide race to hit the market with a CAR-T agent for leukemia. However, damaging news has dogged Juno’s lead agent for acute lymphoblastic leukemia, JCAR015. Earlier this year, three patients died from toxic side effects; this month, two new cases of fatal brain swelling were reported, though a causal link has yet to be established. Meanwhile, as investors vocally worry about class-wide safety concerns, Novartis and Kite Pharma are cautiously tip-toeing to market with their own competing CAR-T products.
What do the dueling stories of Spark and Juno tell us about the future of gene therapy? Despite the fits and starts in clinical research, rapidly increasing investor interest and regulatory motivation have made it clear that the important stakeholders are devoted to seeing gene therapy through to market. Regulators at the FDA and EMA are seeking ways to work with manufacturers to design and execute clinical trials successfully—the FDA, in fact, has shown an unusually high degree of interest to guide Juno to get its JCAR015 trial back on track. Meanwhile, bioethicists are working with governments in the U.S. and Europe to define consistent standards for gene therapy research and interest. And the general trend in industry investment suggests faith in the totality of upward-pointing data, as well-resourced companies such as Pfizer are acquiring early gene therapy startups. As several gene therapy modalities get de-risked through research and investment, we will see a rapid maturation of the market.
Undoubtedly, as questions of ethics, patient access, safety, and market potential are yet to be answered, gene therapy still faces a long road ahead. It’s clear, though, that we are slowly starting to see the promise of gene therapy materialize as we reach this tipping point for its potential success.