P.A. von dem Borne

A randomized phase 3 study on the effect of thalidomide combined with adriamycin, dexamethasone, and high-dose melphalan, followed by thalidomide maintenance in patients with multiple myeloma

The phase 3 trial HOVON-50 was designed to evaluate the effect of thalidomide during induction treatment and as maintenance in patients with multiple myeloma who were transplant candidates. A total of 556 patients was randomly assigned to arm A: 3 cycles of vincristine, adriamycin, and dexamethasone, or to arm B: thalidomide 200 mg orally, days 1 to 28 plus adriamycin and dexamethasone. After induction therapy and stem cell mobilization, patients were to receive high-dose melphalan, 200 mg/m(2), followed by maintenance with alpha-interferon (arm A) or thalidomide 50 mg daily (arm B). Thalidomide significantly improved overall response rate as well as quality of the response before and after high dose melphalan. Best overall response rate on protocol was 88% and 79% (P = .005), at least very good partial remission 66% and 54% (P = .005), and complete remission 31% and 23% (P = .04), respectively, in favor of the thalidomide arm. Thalidomide also significantly improved event-free survival from median 22 months to 34 months (P < .001), and prolonged progression free from median 25 months to 34 months (P < .001). Median survival was longer in the thalidomide arm, 73 versus 60 months; however, this difference was not significant (P = .77). Patients randomized to thalidomide had strongly reduced survival after relapse. This trial was registered on www.controlled-trials.com as ISRCTN06413384.

Comparison of conditioning regimens of various intensities for allogeneic hematopoietic SCT using HLA-identical sibling donors in AML and MDS with <10% BM blasts: a report from EBMT

In this multicenter retrospective study, the long-term outcomes of 878 adults with AML and refractory anemia with excess blasts (RAEB) with BM blasts <10% who underwent transplantation with an HLA-identical sibling donor between 1998 and 2004 were analyzed according to four regimens of conditioning intensity: reduced-intensity conditioning (RIC) (either intermediate RIC (IntermRIC) or non-myeloablative (NMA) RIC), and myeloablative conditioning (MC) in 718 patients (either conventional MC or hyperintense MC. In multivariate cox analysis, patients undergoing NMA transplantation had lower non-relapse mortality risk in the first 100 days after transplantation (P<0.01), but a higher risk beyond day +100 (P=0.02), as well as higher relapse incidence in the first 12 months (P<0.01), but the risk was similar in all groups beyond 12 months. The probabilities of PFS and OS up to 7 years were significantly lower only in the NMA subgroup (P⩽0.01 for both). The 7-year OS was 53%, 29%, 56% and 51%, respectively. Our data suggest that prospective studies comparing RIC regimens (especially IntermRIC) with MC are appropriate in patients with AML and RAEB who are in a non-advanced disease status.

Myeloablative T cell-depleted alloSCT with early sequential prophylactic donor lymphocyte infusion is an efficient and safe post-remission treatment for adult ALL

The prognosis of adult patients with ALL remains unsatisfactory. AlloSCT is associated with a beneficial GVL response mediated by donor T cells. However, GVHD results in substantial mortality and long-term morbidity. T-cell depletion (TCD) of the graft reduces the severity of GVHD, but is associated with an increased relapse rate after alloSCT. Therefore, early sequential donor lymphocyte infusion (DLI) is likely to be necessary for a successful GVL reaction. Twenty-five adult ALL patients (10 Ph+ALL) were eligible for early DLI after initial disease control with myeloablative TCD-alloSCT in first CR (CR1), if active GVHD was absent at 3–6 months after alloSCT. Patients with a sibling donor or an unrelated donor were scheduled for 3.0 × 106 CD3+ cells/kg or 1.5 × 106 CD3+ cells/kg, respectively, at 6 months after alloSCT. Three patients died before evaluation (one early relapse). Five patients had active GVHD. Fourteen of the remaining seventeen patients received DLI (median time-to-DLI: 185 days). Overall, only 17% required long-term systemic immunosuppression for GVHD. With a median follow-up after TCD-alloSCT of 50 months, 2-year survival probability was 68% (95% confidence interval (CI) 49–87%). In conclusion, myeloablative TCD-alloSCT with early sequential DLI is an efficient and safe post-remission treatment for adult ALL patients in CR1.

Viral loads and antiviral resistance of herpesviruses and oral ulcerations in hematopoietic stem cell transplant recipients

Ulcerative oral mucositis and infection are frequent complications in hematopoietic stem cell transplant (HSCT) recipients. The aim of this study was to investigate the relationship between oral ulcerations and HSV-1, EBV and CMV excretion and the presence of aciclovir-resistant HSV-1 strains in HSCT recipients. This prospective observational study included 49 adult patients who underwent allogeneic HSCT. In total, 26 patients received myeloablative and 23 received non-myeloablative conditioning. Ulcerations on non-keratinized and keratinized oral mucosa were scored and oral rinsing samples were taken twice weekly. Viral loads were determined by real-time PCR. Samples from patients remaining HSV-1 positive despite antiviral treatment were studied for resistance to antivirals. Having an HSV-1 or EBV DNA–positive sample was a significant predictor for ulceration of keratinized mucosa. HSV-1 was a significant predictor for ulcerations on non-keratinized mucosa as well. Persistent HSV-1 infection occurred in 12 of 28 patients treated with antiviral medication and aciclovir-resistant HSV-1 was found in 5 persistent infections. In conclusion, HSV-1 is a predictor of ulcerations on non-keratinized as well as keratinized oral mucosa following HSCT. The role of EBV deserves further study. Persistent HSV-1 replication despite antiviral treatment is common and is due to resistance in 18% of treated patients.

Predictive impact of allele-matching and EBMT risk score for outcome after T-cell depleted unrelated donor transplantation in poor-risk acute leukemia and myelodysplasia

Many parameters predict for outcome after unrelated donor (URD) allogeneic hematopoietic stem cell transplantation (alloSCT). High-resolution HLA-matching significantly impacts outcome and also the European Group of Blood and Marrow Transplantation (EBMT) risk score, based on patient age, disease stage, donor type, time from diagnosis to SCT and gender combination, may predict for non-relapse mortality and overall survival (OS). We evaluated the individual and combined effects of allele-matching and the EBMT risk score in 327 patients with poor-risk acute leukemia or myelodysplasia, who received a T-cell depleted URD alloSCT. Matching for HLA-A, -B, -C and -DRB1 alleles (8/8 match) was associated with a 5-year OS of 40% compared with 30% for mismatched (⩽7/8) pairs (P=0.02). Patients with EBMT risk scores of 1–2, 3, 4 and 5–7 had 5-year OS estimates of 53, 43, 30 and 20%, respectively (P<0.001). The favorable prognostic impact of an 8/8 donor was most pronounced if the EBMT risk score was low (1–2). Five-year OS was 74±8% vs 39±11% for fully matched patients with a low-risk EBMT score as compared with EBMT low-risk patients with ⩽7/8 donors. These data underscore the importance of incorporating both the EBMT risk score and the degree of high-resolution HLA-matching in the risk assessment prior to URD alloSCT.

Effect of genetic polymorphisms in genes encoding GST isoenzymes on BU pharmacokinetics in adult patients undergoing hematopoietic SCT

BU is used in conditioning regimens before hemopoietic SCT. High BU exposure is associated with toxicity, whereas low BU exposure leads to higher rates of therapy failure. The pharmacokinetics of BU show large interpatient variability, hypothesized to be caused by variability in BU metabolism. In this report, the effect of genetic polymorphisms in three gluthatione S-transferase genes involved in BU metabolism (hGSTA1), GSTM1 (deletion–mutation) and GSTP1 (313A/G) on the pharmacokinetics of BU in Caucasian adult patients was investigated. In all, 66 adult patients received BU as part of their conditioning regimen. After the first infusion, two serum samples were collected and measured using a HPLC assay. A one-compartment population model was used to estimate individual pharmacokinetic parameters. The genetic variants of the three glutathione S-transferase (GST) genes were determined by pyrosequencing and PCR. A reduction of 14% in BU clearance was seen for the GSTA1*B allele and an increase in BU exposure was found. No relationship was found between polymorphisms in GSTM1 and GSTP1 and BU pharmacokinetics. This study shows that an increasing number of copies of GSTA1*B allele results in a significant decrease of BU clearance.

Molecular persistence of chronic myeloid leukemia caused by donor T cells specific for lineage-restricted maturation antigens not recognizing immature progenitor-cells.

Although donor lymphocyte infusion (DLI) induces complete remissions in 70% of patients with relapsed chronic myeloid leukemia (CML) after allogeneic stem-cell transplantation (SCT), some patients are refractory to DLI by showing disease persistence. In a patient who received DLI for relapsed CML, we observed persisting molecular disease despite a hematological and cytogenetic remission in the absence of graft-versus-host disease (GVHD). To determine the nature of this immune response, we isolated leukemia-reactive donor T-cell clones from the bone marrow (BM) of the patient at the time of clinical response. Four different types of CD8+ HLA class I restricted T-cell clones were obtained that were cytotoxic against Ebstein–Barr virus-transformed B-cell lines (EBV-LCL) of the patient, but not the donor, indicating recognition of minor histocompatibility antigens (mHags). By using survival studies with CFSE labelled BM cells populations, a hematopoietic progenitor cell inhibition assay and direct morphological examination we showed that the T-cell clones recognized mature monocytic and myeloid cells, whereas immature BM progenitor cells were insufficiently lysed. This patients refractoriness for DLI appears to be caused by inadequate lysis of progenitor cells by these cytotoxic T cells. These findings support the hypothesis that for eradication of CML a cytotoxic T-cell response against leukemic progenitor cells is essential.

The impact of frequent HLA haplotypes in high linkage disequilibrium on donor search and clinical outcome after unrelated haematopoietic SCT

The MHC region on chromosome 6 contains a large number of non-HLA genes next to the HLA genes. Matching for HLA in unrelated hematopoietic SCT (HSCT) does not necessarily mean that these non-HLA genes are also matched. We selected 348 Northwest European patients transplanted with an HLA-A-, -B-, -C-, -DRB1-, -DQB1-matched unrelated donor (MUD) between 1987 and 2008. Patients’ haplotypes were identified via descend. We were unable to determine the haplotypes of the donor; therefore we used frequent haplotypes (FH) in high linkage disequilibrium (LD) as a proxy for haplotype matching. Presence of a FH in a patient positively affected the probability and speed of identifying a matched unrelated donor. Competing risk survival analysis showed that patients with one or two FH have a statistically significantly decreased probability of developing ⩾grade II acute GVDH (aGVHD) without increased risk of relapse compared to patients without FH (HR (95% CI): 0.53 (0.31–0.91)). This association was strongest for those FH with the highest LD between both HLA-A and -C or –B, and HLA-C or –B and -DRB1 (HR (95% CI): 0.49 (0.26–0.92)). These results extend evidence that non-HLA allele coding regions have a significant impact on development of ⩾grade II aGVHD. We conclude that there is more to successful HSCT than matching for HLA genes.

Physiochemical disparity of mismatched HLA class I alloantigens and risk of acute GVHD following HSCT

We determined whether assessment of the immunogenicity of individual donor–recipient HLA mismatches based on differences in their amino-acid sequence and physiochemical properties predicts clinical outcome following haematopoietic SCT (HSCT). We examined patients transplanted with 9/10 single HLA class I-mismatched grafts (n=171) and 10/10 HLA-A-, -B-, -C-, -DRB1- and -DQB1-matched grafts (n=168). A computer algorithm was used to determine the physiochemical disparity (electrostatic mismatch score (EMS) and hydrophobic mismatch score (HMS)) of mismatched HLA class I specificities in the graft-versus-host direction. Patients transplanted with HLA-mismatched grafts with high EMS/HMS had increased incidence of ⩾grade II acute GVHD (aGVHD) compared with patients transplanted with low EMS/HMS grafts; patients transplanted with low and medium EMS/HMS grafts had similar incidence of aGVHD to patients transplanted with 10/10 HLA-matched grafts. Mortality was higher following single HLA-mismatched HSCT but was not correlated with HLA physiochemical disparity. Assessment of donor–recipient HLA incompatibility based on physiochemical HLA disparity may enable better selection of HLA-mismatched donors in HSCT.

Donor lymphocyte infusions for the treatment of chronic myeloid leukemia relapse following peripheral blood or bone marrow stem cell transplantation

Peripheral blood used as a source of stem cells for transplantation (PBSCT) is known to exert stronger immune-mediated effects compared with BM (BMT). We decided to retrospectively analyze the impact of stem cell source on the OS of CML patients who relapsed after either matched related donor PBSCT (N=168) or BMT (N=216) and were treated with donor lymphocyte infusions (DLI). Univariate analysis revealed a lower probability of OS after DLI in patients relapsing after PBSCT vs BMT (66% vs 79% at 5 years, P=0.013). However, a multivariate Cox analysis did not reveal any significant impact of PBSCT as a risk factor for decreased OS for patients transplanted in first chronic phase (CP1; hazard ratio (HR) 1.036, 95% confidence interval (CI) 0.619–1.734). A statistical interaction term suggested that the impact of stem cell source on OS after DLI was different for those transplanted in advanced phases (negative impact of previous PBSCT—HR 2.176, 95% CI 0.930–5.091). In summary, the stem cell source does not affect the OS of CML patients who underwent PBSCT in CP1, relapsed and were treated with DLI. However, when the patients were transplanted in advanced phases, previous PBSCT seems to negatively affect OS after DLI compared with BMT.