Retroviral Vector Technology for Gene Therapy: History, Current Landscape, and Future Prospects

The concept of gene therapy and its practice has been prevalent for over five decades. The first successful retroviral vector-based gene therapy trial took place ∼35 years ago, followed by several setbacks. However, recent years have seen a surge in successes, offering new hope to patients with genetic and other disorders once deemed untreatable. Over the past decade, rapid advancements in molecular biology have led to the development of safer and more effective gene therapy strategies with various gene delivery systems now in use. Among these, viral vectors such as retroviruses, adenoviruses, and adeno-associated viruses are the most widely employed in both research and clinical settings. This is due to their natural efficiency in delivering genetic material into target cells. Among these viral vectors, retroviruses stand out for their unique ability to reverse-transcribe and integrate their genetic material into the host genome, ensuring stable and long-term gene expression. This review highlights advances in retroviral vector development, examining both their therapeutic potential and associated challenges. It also explores strategies for vector production, including transient and stable systems tailored to meet clinical and regulatory demands. Significant progress is discussed in mitigating insertional mutagenesis and vector silencing. As a result, next-generation retroviral vectors with improved safety and efficacy have made it past regulatory approval and are commercially available. Current innovations include replication-competent, non-integrating, integration-retargeted, and hybrid CRISPR/Cas-expressing retroviral vectors undergoing pre-clinical and clinical investigations. This reflects a new era in gene therapy, with retroviral vectors reimagined for greater precision, control, and therapeutic impact.