Saudi Arabia is the largest of the Arabian Gulf countries with a total population of 33.41 million as of 2017. This report summarizes the experience from four leading tertiary care hematopoietic stem cell transplantation (HSCT) centers in Saudi Arabia representing more than 90% of all HSCTs performed in the country. Between 1984 and 2016, a total of 6,184 HSCTs were performed. Of these, 3,586 HSCTs were performed in adults and 2,598 HSCTs were performed in pediatric patients. Malignancy was the main indication for transplantation (47%). While most transplants were performed from an identical sibling donor, HSCTs from cord blood, unrelated and, more recently, haploidentical donors have also been performed. Relative shortage of HSCT bed capacity is perceived to be a limiting factor in Saudi Arabia. Lately, more HSCT centers are emerging with rapid growth, which may significantly improve the access to HSCT in the country in the near future.
Treatment for relapse of chronic myeloid leukemia (CML) following hematopoietic cell transplantation (HCT) includes tyrosine kinase inhibitors (TKIs) with or without donor lymphocyte infusions (DLIs), but the most effective treatment strategy is unknown. This study was performed through the Center for International Blood and Marrow Transplant Research (CIBMTR) database. We retrospectively reviewed all patients reported to the CIBMTR registry from 2002 to 2014 who underwent HCT for CML and were alive 30 days postrelapse. A total of 215 HCT recipients relapsed and were analyzed in the following groups: (1) TKI alone (n = 128), (2) TKI with DLI (n = 48), and (3) DLI without TKI (n = 39). In multivariate analysis, disease status prior to HCT had a significant effect on overall survival (OS). Patients who received a DLI alone compared with a TKI with a DLI had inferior survival (hazard ratio, 2.28; 95% confidence interval, 1.23 to 4.24; P= .009). Those who received a TKI alone had similar survival compared with those who received a TKI with a DLI (P = .81). These data support that despite use of TKIs pretransplantation, TKI salvage therapy continues to provide significant survival following relapse in patients with CML following HCT. These data do not suggest that adding a DLI to a TKI adds an improvement in OS.
Between March 1984 and December 1999, a total of 43 second related allogeneic BMT procedures after myeloablative conditioning were carried out in our institution, 37 following allogeneic, and 6 following autologous BMT. Thirty one patients were males (72%). At 1st BMT (BMT1), median age was 11.5 years (range, 0.16-45 years). BMT1 was carried out for the diagnosis of AML in 13 patients (30%), SAA in nine (21%), ALL in six (14%), CML in six (14%), immunodeficiency in three (7%), NHL in two, beta-thal in two, HD in one, Red cell aplasia in one. HLA matching status for allogeneic BMT1 was full match in 33, one antigen mismatch in two and haplo identical in two patients. Median age at the 2nd BMT (BMT2) was 14 years (range, 0.41-46.7 years). Indications for BMT2 were recurrent hematologic neoplasm in 23 patients (53%), primary graft failure in 12 (28%) and late graft failure in 8 (19%). Median time from BMT1 to recurrence of hematologic neoplasm or late graft failure was 10 months (range, 2.5- 88 months). Median BMT1 to BMT2 interval was 13 months (range, 1-107 months). For BMT2, the same donor was used in 29 patients, while 14 patients had alternate related donor (12 full match, 1-one Ag mismatch, 1 haplo identical). A different conditioning regimen was used in the majority of the patients (39, 91%). Radiation containing conditioning regimen were used mostly for patients previously conditioned with chemotherapy only for BMT1 and chemotherapy conditioning +/- ATG for those who received radiation containing conditioning at BMT1. Bone marrow was the stem cell source for all patients at BMT2 and all except three autologous peripheral stem cell transplantation patient at BMT1. Significant organ toxicity leading to procedure related death in 13 patients (30%) was observed after BMT2. At a median follow up of 36 months after BMT2, 22 patients (51%) are alive (20 free of disease, 2 with recurrent disease) with overall median survival of 47.5 (SD +/- 9) months. Univariate analysis of relevant clinical factors identified the following variables as the only statistically significant favorable prognostic factors for overall survival: BMT1-BMT2 interval of > or = 6 months (P=0.0007) and age at BMT2 < or = 10 years (P=0.041). The nature of underlying disease (neoplastic or non-neoplastic) was not statistically significant (P=0.23). There was no statistically significant difference in survival outcome of BMT2 using same donor vs. alternate related donor (P=0.51). Due to the relatively limited sample size, multivariate analysis was not attempted. This single institution study suggests that second allogeneic BMT after myeloblative conditioning has an acceptable treatment related morbidity/mortality and favorable outcome if performed at age < or = 10 years and with an interval of > or = 6 months after the first BMT. Additionally same donor can successfully be used for the second transplant with similar survival outcome to alternate donor.
