The case of the Berlin patient generated widespread interest in cell-based curative interventions. Allogeneic transplantation with stem cells from very rare donors who are naturally resistant to HIV is not a feasible strategy; therefore, much interest is now focused on gene therapy to delete the virus from infected cells or to produce cells resistant to HIV infection.30 Three classes of DNA-editing enzymes are being studied for safety and efficacy to target HIV coreceptors and pro-viral sequences: zinc-finger nucleases, transcription activator-like effector nucleases, and homing endonucleases.31 and 32 The targeted gene-therapy approach of blocking CCR5 (CCR5–zinc-finger nuclease knockout T cells) is under investigation in phase 1 clinical trials of adoptive transfer of ex-vivo expanded autologous T cells (table 1).33 Phase 1 studies have shown that these approaches are safe and feasible. Other gene-based treatments that target HIV viral proteins with either an anti-HIV ribozyme or antisense RNA oligonucleotide constructs have been shown to safely and feasibly reduce viral load in phase 1 and phase 2a clinical trials.34 Additionally, CD4 aptamer-CCR5-siRNA chimeras have proven to be safe and efficacious in the humanised mouse model.35 Interventions that interfere with pre-integration steps in the viral-life cycle are promising, and are being assessed in phase 1 trials.36 The safety and efficacy of gene delivery to specific cells and tissues, and access to these treatments, are major challenges for these approaches in the eradication of HIV infection.37