An effective graft-versus-host disease (GVHD) preventative approach that preserves the graft-versus-tumor effect after allogeneic hematopoietic stem cell transplantation (HSCT) remains elusive. Standard GVHD prophylactic regimens suppress T cells indiscriminately and are suboptimal. Conversely, post-transplantation high-dose cyclophosphamide selectively destroys proliferating alloreactive T cells, allows the expansion of regulatory T cells, and induces long-lasting clonal deletion of intrathymic antihost T cells. It has been successfully used to prevent GVHD after allogeneic HSCT. Bortezomib has antitumor activity on a variety of hematological malignancies and exhibits a number of favorable immunomodulatory effects that include inhibition of dendritic cells. Therefore, an approach that combines post-transplantation cyclophosphamide and bortezomib seems attractive. Herein, we report the results of a phase I study examining the feasibility and safety of high-dose post-transplantation cyclophosphamide in combination with bortezomib in patients undergoing allogeneic peripheral blood HSCT from matched siblings or unrelated donors after reduced-intensity conditioning. Cyclophosphamide was given at a fixed dose (50 mg/kg on days +3 and +4). Bortezomib dose was started at .7 mg/m2, escalated up to 1.3 mg/m2, and was administered on days 0 and +3. Patients receiving grafts from unrelated donors also received rabbit antithymocyte globulin. The combination was well tolerated and allowed prompt engraftment in all patients. The incidences of acute GVHD grades II to IV and grades III and IV were 20% and 6.7%, respectively. With a median follow-up of 9.1 months (range, 4.3 to 26.7), treatment-related mortality was 13.5% with predicted 2-year disease-free survival and overall survival of 55.7% and 68%, respectively. The study suggests that the combination of post-transplantation cyclophosphamide and bortezomib is feasible and may offer an effective and practical GVHD prophylactic regimen. The combination, therefore, merits further examination.
Next-generation sequencing (NGS) capabilities can affect therapeutic decisions in patients with complex, advanced, or refractory cancer. We report the feasibility of a tumor sequencing advisory board at a regional cancer center. Specimens were analyzed for approximately 2800 mutations in 50 genes. Outcomes of interest included tumor sequencing advisory board function and processes, timely discussion of results, and proportion of reports having potentially actionable mutations. NGS results were successfully generated for 15 patients, with median time from tissue processing to reporting of 11.6 days (range, 5 to 21 days), and presented at a biweekly multidisciplinary tumor sequencing advisory board. Attendance averaged 19 participants (range, 12 to 24) at 20 days after patient enrollment (range, 10 to 30 days). Twenty-seven (range, 1 to 4 per patient) potentially actionable mutations were detected in 11 of 15 patients: TP53 (n = 6), KRAS (n = 4), MET (n = 3), APC (n = 3), CDKN2A (n = 2), PTEN (n = 2), PIK3CA, FLT3, NRAS, VHL, BRAF, SMAD4, and ATM. The Hotspot Panel is now offered as a clinically available test at our institution. NGS results can be obtained by in-house high-throughput sequencing and reviewed in a multidisciplinary tumor sequencing advisory board in a clinically relevant manner. The essential components of a center for personalized cancer care can support clinical decisions outside the university.
Graft versus host disease (GvHD) remains a major barrier to the progress of blood and marrow transplantation and limits its wide applicability. Standard prophylactic regimens essentially targeting T lymphocytes are partially effective and burdensome. Cyclophosphamide (Cy) administered post-transplant selectively deletes alloreactive proliferating T cells, promotes expansion of regulatory T cells, and induces long-lasting depletion of intrathymic host-reactive T cells. It is an attractive option for prevention of GvHD and has already been used alone in matched related and unrelated donor transplants. However, despite a low incidence of chronic GvHD, acute GvHD still occurs in 50% of cases and is grade III-IV in 15% of cases. Dendritic cells (DCs) play a pivotal role in the early phase of GvHD. Proteasome inhibitors such as bortezomib (Bor) have a number of immunomodulatory effects including inhibition of DCs maturation and function. We therefore initiated a phase I feasibility study combining post-transplant Cy & Bor. Twelve patients with hematological malignancies undergoing peripheral blood allogeneic transplantation from matched related (n=6) or unrelated (n=6) donors have so far been enrolled. Disease risk index (DRI) was low in 4, intermediate in 3 and high or very high in 5. The conditioning regimen combined fludarabine and busulfan (total 6.4 mg/kg). Patients receiving graft from unrelated donors also received rabbit anti-thymocyte globulin at 5-8 mg/kg. The dose of Bor was escalated in standard fashion. Three patients in each of cohorts 1 and 2 received 0.7 and 1 mg/m2 respectively. The subsequent 6 patients received 1.3 mg/m2. All patients received 2 IV doses, 6 hours after graft infusion and 72 hours thereafter. Cy was given at 50 mg/kg IV on days +3 and +4. Steroids were not allowed after day 0. Engraftment was prompt in all patients. Median time to neutrophil engraftment was 15.5 days (range 14-25). One patient failed to meet criteria for platelet engraftment. The patient had acyclovir-resistant herpes genitalis and CMV reactivation requiring protracted therapy with foscarnet. The remaining patients had a median time to platelet recovery of 28 days (range 15-109). All patients achieved full chimerism by day 20 except one who had residual CLL and did not reach full chimerism until day +119. No patient developed secondary graft failure. Two treatment-related deaths occurred on day +150 due to RSV pneumonitis and on day +200 due to acute sepsis. One patient with recurrent multiple myeloma after autologous transplantation died due to progressive disease. No other Common Toxicity Criteria grade 3 or 4 occurred in any patient. With a median follow-up of 21 months (range 1-27), the overall 2-year predicted disease free survival and overall survival were both 60%. Incidence of acute GvHD in 11 patients with follow-up > 100 days, was 64%: grade I 55%, grade II 9%, and grade III-IV 0%. GI and liver acute GvHD were not encountered. Only 4 patients received systemic steroids for acute GvHD; only one required > 20 mg/day of prednisone. One patient developed chronic GvHD of the liver (biopsy-proven). Another patient developed poor appetite and weight loss on day +138. Endoscopy showed gastric ulceration. No biopsy was obtained. Neither calcineurin nor m-TOR inhibitors were ever used. Two patients developed extensive HSV-genito-rectal ulcers; one had prior history of recurrent flares. When institutional guidelines were changed to start acyclovir at the beginning of conditioning as opposed to day +5, no other cases was noted. Seven patients developed CMV reactivation and required preemptive therapy only. One patient developed BK virus-induced hematuria and 1 patient developed CNS toxoplasmosis. In summary, the calcineurin and m-TOR inhibitor-free post-transplant Cy & Bor combination for GvHD prophylaxis is feasible and safe. Although the small number of patients prevents any definite conclusion, the absence of incidence of grade III-IV acute GvHD and the sparing of the GI tract and liver are promising. Furthermore, the completion of GvHD prophylaxis by day +4 without the need for close renal and drug level monitoring are both practical and appealing. Updated results with longer follow-up will be reported at the meeting. A confirmatory phase II study is underway. Disclosures Al-Homsi: Millennium Pharmaceuticals: Research Funding. Off Label Use: Bortezomib use for aGvHD prevention.
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