Torloni, Sergio

Background Steroid-refractory (SR) acute graft-versus host disease (aGVHD) is a serious complication of allogeneic HCT, for which there is no established standard treatment. Both ECP and cytokine inhibitors such as Infliximab have apparent single agent activity in the therapy of SR aGVHD, but there are no published data that address the efficacy of combination anticytokine therapy and ECP in this setting. We report here results in 18 adult patients (pts) with grade III or IV SR aGVHD who were treated with concurrent Infliximab and ECP. Patients All pts underwent allogeneic HCT (first transplant, n=15, second transplant, n=3) for a hematologic malignancy at Mayo Clinic Arizona between March 2012 and May 2013. The median age was 61 (range 22-70), and the median follow-up of 6 surviving pts is 263 days (range 79-433). Donors were related in 3, matched unrelated in 8, and mismatched unrelated in 7. GVHD prophylaxis consisted of tacrolimus and mycophenolate mofetil in 13 pts and tacrolimus/methotrexate in 5; in addition, 17 pts received in vivo T-cell depletion with Thymoglobulin 2.5 – 7.5 mg/kg. All pts developed grades III-IV aGVHD at a median day 27 post-transplant (range 10-107) and failed to respond to a course of high-dose corticosteroids (methylprednisolone or equivalent 2 mg/kg daily) for at least 5 days. Treatment Regimen At diagnosis of SR aGVHD, pts were scheduled to receive weekly Infliximab 10 mg/kg (maximum 4 doses), concurrent with ECP performed twice or thrice weekly for one month, followed by a pre-specified taper schedule (anticipated total treatment duration of 6-9 months). To minimize infectious risk and morbidity, corticosteroids were tapered rapidly after the start of Infliximab/ECP therapy. Results Thirteen pts (72%) responded to the Infliximab/ECP combination; complete response (CR; resolution of all GVHD symptoms for at least 30 days and able to discontinue corticosteroids) was observed in 6 pts (33%), and partial response (PR; improvement in GVHD symptoms, partial taper of corticosteroids, and no additional agent for at least 30 days) in 7 pts (39%). At the time of this report, 6 pts are alive, and the Kaplan-Meier estimate of one-year survival is 22.5 % (95% CI, 8.8%-47%). Only pts who achieved CR had good outcomes (5/6 surviving and clinically well); among 13 pts with PR (7) or no response/progression (6) to Infliximab/ECP, 12 have died and one is day 79 post transplant and remains on ECP and low-dose prednisone. Eleven of the 12 deaths were related to GVHD or complications of its treatment (infection, multi-organ failure). Conclusions In this retrospective study of adult pts with severe (grade III/IV) SR aGVHD, treatment with 4 doses of weekly Infliximab and concurrent ECP resulted in an overall response rate of 72%, with one-third of pts achieving CR; the regimen was well-tolerated and facilitated early taper and rapid discontinuance of corticosteroids. Unfortunately, the overall survival of 22.5% at one year does not appear superior to other single agent or combination therapies reported in the literature, or to historical data from our program. Although a small percentage of pts appear to be long-term survivors, the majority of pts succumb to complications of progressive GVHD or infection. Given poor results with available therapies, and the dismal prognosis of pts with SR aGVHD, future research should focus on better preventative strategies for this devastating complication of allogeneic HCT. Disclosures: No relevant conflicts of interest to declare.

Abstract Background: Peripheral Blood Progenitor Cells (PBPC) cryopreserved in DMSO are thawed at the patient’s bedside and infused immediately. Usually the infusions are completed without incident. There are occasions when mild/severe transfusion related reactions occur. When this does occur, the infusion is either slowed or paused for a short period of time. When reactions are severe enough to warrant stoppage of the infusion, transplant facilities maybe faced with discarding any remaining thawed cells. We have explored the question of salvaging the remaining cells by re-cryopreservation using two cryopreservation methods. Study Design: Twenty PBPC were thawed in a 37C water bath until the internal temperature of the cells was approx 2-6C. The PBPC were not washed and allowed to remain at room temperature for 15 minutes. Ten PBPC were then placed on ice for 45 minutes. This simulated the transfer of cells to an off-site cryopreservation lab. These cells were then transferred to a new cryo bag, no change in the cryoprotectant solutions, and placed into a rate controlled freezer (RCF) bringing their temperature back to <−160C. The remaining 10 PBPC were allowed to remain at room temperature for an additional 10 minutes. The PBPC were then transferred to a −80C mechanical freezer. This simulated the transfer of cells to an internal laboratory without cryopreservation capabilities. All 20 PBPC were thawed after a minimum of 24 hours after return to their respective storage freezer conditions. We measured total nucleated cell count, viability by trypan blue, and CFU after the initial thaw and after the second thaw. Results: The median viability of all PBPC after the first thaw was 69.5% (n=20; range= 35–83%). The median post thaw viability of the PBPC frozen by the RCF was 55.5% (n=10; range= 18–73%). Whereas, the median post thaw viability of the PBPC frozen in the −80C freezer was 25% (n=10; range 8–37%). Additionally, the median percent of viable cell loss from the initial pre-freeze data to the second thaw data for the RCF PBPC was 66.1% (n=10; range= 0 – 94.6%) and for the −80C PBPC was 94.1% (n=10; range= 91.3–97.8%. CFU growth was present for the RCF PBPC. No growth was demonstrated for the −80C PBPC. Conclusion: Though neither method provided outstanding results, if faced with the dilemma of losing cells or attempting to save by re-cryopreservation, a transplant facility should consider RCF over −80C freezing.