The invention provides improved gene therapy methods and compositions. In particular embodiments, gene therapies comprise hematopoietic stem and progenitor cell compositions with increased therapeutic efficacy and methods of making and using the same. In other particular embodiments, the present invention contemplates compositions and methods for increasing transduction efficiency and vector copy number (VCN) of human hematopoietic stem and progenitor cells (HSPCs) to yield improved gene therapy compositions. In various embodiments, the present invention contemplates, in part, a population of HSPCs transduced with a lentiviral vector. In various embodiments, the present invention contemplates a method of treating sickle cell disease in a subject comprising administering the subject an effective amount of the population of hematopoietic cells contemplated herein. In various embodiments, the present invention contemplates a kit comprising an agent that increases prostaglandin EP receptor signaling and staurosporine.