Results of the First Clinical Study in Humans That Combines Hyperbaric Oxygen Pretreatment with Autologous Peripheral Blood Stem Cell Transplantation

•Hyperbaric oxygen (HBO) therapy incorporation into autologous hematopoietic cell transplantation (auto-HCT) is feasible.•HBO potentially improves time to neutrophil and platelet recovery in auto-HCT.•HBO potentially reduces mucositis and growth factor use in auto-HCT.•Further studies are needed to study HBO in auto-HCT. Patients undergoing high-dose chemotherapy and autologous hematopoietic cell transplantation (auto-HCT) are at risk for multiple morbidities, including mucosal inflammation and neutropenic fever, both related to neutropenia. Evidence from our preclinical work in an umbilical cord blood (UCB) transplantation murine model suggests that treatment with hyperbaric oxygen (HBO) before UCB infusion improves UCB CD34+ cell engraftment by reducing erythropoietin levels. A pilot clinical trial using HBO in patients undergoing UCB transplantation showed improvement in kinetics of blood count recovery. In this study, we evaluated HBO in combination with auto-HCT. Our primary aim was to determine the safety of HBO in this setting and secondarily to determine its efficacy in reducing time to neutrophil and platelet engraftment compared with matched historic controls. Patients with multiple myeloma, non-Hodgkin lymphoma, and Hodgkin disease eligible for auto-HCT were included. On day 0, patients received HBO treatment consisting of exposure to 2.5 atmosphere absolutes for a total of 90 minutes, in a monoplace hyperbaric chamber, breathing 100% oxygen. Six hours after the start of HBO, peripherally mobilized stem/progenitor cells were infused and patients were followed daily for toxicity and blood count recovery. All patients received daily granulocyte colony-stimulating factor starting on day +5 and until absolute neutrophil count (ANC) of ≥1500 or ANC of 500 for 3 consecutive days. A matched historic cohort of 225 patients who received auto-HCT between January 2008 and December 2012 was chosen for comparison and matched on sex, age, conditioning regimen, and disease type. We screened 26 patients for this study; 20 were treated and included in the primary analysis, and 19 completed the HBO therapy and were included in the secondary analysis. Although the median time to neutrophil count recovery was 11 days in both the HBO and control cohorts, the Kaplan-Meier estimates of the full distributions indicate that the time to neutrophil recovery was generally about 1 day sooner for HBO versus historical controls (log-rank P = .005; range, 9 to 13 for HBO patie