Development of the First World Health Organization Lentiviral Vector Standard: Toward the Production Control and Standardization of Lentivirus-Based Gene Therapy Products

Toward the Cure of HIV-1 Infection: Lessons Learned and Yet to be Learned as New Strategies are Developed

Here, we review the progress that has been made in achieving a cure of HIV-1 infection. To date, this has only occurred in one person after he received allogeneic stem cell transplants from a CCR5 ∆32 homozygous donor in addition to chemotherapy and radiation to treat his acute myelocytic leukemia. The general consensus is that achieving a sustained remission of infection in the absence of antiretroviral therapy will involve a combination of strategies that involve both the targeting of the latent proviral genome and the induction of more effective anti-HIV-1 immune responses. Efforts to reverse HIV-1 proviral DNA integration in the host cell genome and those to enhance anti-HIV immunity have been disappointing thus far. The lack of clinically validated assays to measure both effects has hampered the development of effective therapies. We suggest the consideration of genome editing as a new approach to reduce the latently integrated proviral genome. In addition, new approaches to therapeutic immunization, alterations of immunoregulatory pathways, anti-HIV-1 antibodies, and anti-HIV-1 chimeric antigen receptor T lymphocytes are in development.

Hurdles Associated with the Translational Use of Genetically Modified Cells

Purpose of Review

Recent advancements in the use of genetically modified hematopoietic stem cells (HSCs) and the emergent use of chimeric antigen receptor (CAR) T-cell immunotherapy has highlighted issues associated with the use of genetically engineered cellular products. This review explores some of the challenges linked with translating the use of genetically modified cells.

Recent Findings

The use of genetically modified HSCs for ADA-SCID now has European approval and the U.S. Food and Drug Administration recently approved the use of CAR-T cells for relapsed/refractory B-cell acute lymphoblastic leukemia. Current good manufacturing processes have now been developed for the collection, expansion, storage, modification, and administration of genetically modified cells.

Summary

Genetically engineered cells can be used for several therapeutic purposes. However, significant challenges remain in making these cellular therapeutics readily available. A better understanding of this technology along with improvements in the manufacturing process is allowing the translation process to become more standardized.