Intracavernous Injections of Bone Marrow Mononucleated Cells for Postradical Prostatectomy Erectile Dysfunction: Final Results of the INSTIN Clinical Trial

Abstract We recently reported stage I of a phase 1/2 clinical trial of cell therapy to treat postradical prostatectomy erectile dysfunction (INSTIN, INtra-cavernous STem-cell INjection clinical trial, NCT01089387). In this first stage, four doses of intracavernous autologous bone marrow mononuclear cells (BM-MNCs) were tested in 12 patients. Here, we report the results of stage II, in which six additional patients received the optimal dose identified in stage I (10 9 BM-MNCs), and the long-term results in the 12 patients included in stage I. The objectives were to assess the safety and efficacy of this new treatment. In stage II, no patients had side effects, and the erectile function improvements were similar to those seen in stage I: after 6 months, significant improvements versus baseline were noted in International Index of Erectile Function-15 intercourse satisfaction (7.8±3.1 vs 2.2±3.4, p =0.033) and erectile function (18±8.3 vs 3.7±4.1, p =0.035) domains. In stage I patients, after a mean follow-up of 62.1±11.7 mo, there were no prostate cancer recurrences, and erectile function scores were somewhat lower compared with the 1-yr time point. These findings suggest that intracavernous BM-MNC injections are safe and improve erectile function. The decline in erectile function over time suggests a need for assessing repeated injections. Patient summary We report a phase 1/2 pilot clinical trial of cell therapy consisting in intracavernous injection of bone marrow mononuclear cells to treat postradical prostatectomy erectile dysfunction. Erectile function was improved after 6 mo in the patients given 1×10 9 cells. No serious side effects (life threatening or requiring hospitalisation) occurred after a mean follow-up of 62.1 mo in the first 12 patients.