D Caballero

Chimerism and minimal residual disease monitoring after reduced intensity conditioning (RIC) allogeneic transplantation

Since graft-versus-leukemia (GVL) is the main weapon for disease eradication after reduced intensity conditioning (RIC) allogeneic SCT, the availability of sensitive and specific techniques to monitor changes in tumor load after transplant are especially helpful. These minimal residual disease techniques would allow an early intervention in the event of low tumor burden, for which immunotherapy is highly effective. Some authors have found an association between persistence of MRD, mixed chimerism and risk of relapse. Nevertheless, data from the literature remain contradictory and further correlations should be established, especially in RIC transplants. In this study we have analyzed the impact of MRD and chimerism monitoring on the outcome of 34 patients undergoing RIC allogeneic SCT who were considered poor candidates for conventional transplantation due to advanced age or other concurrent medical conditions. At day +100 25 (75%) patients reached complete remission (CR), there were five (15%) partial responses and three patients progressed. Incidence of grade 2–4 aGVHD and extensive cGVHD were 35% and 58%, respectively. Sixteen percent of patients developing aGVHD relapsed as compared to 47% in those without aGVHD (P = 0.03) and also 10% of patients developing cGVHD relapsed as compared to 50% relapses in those without cGHVD (P = 0.03). Four patients (12%) died due to early (n = 1) and late (n = 3) transplant-related mortality. After a median follow-up of 15 months, 24 out of the 34 patients remain alive. Projected overall survival and disease-free survival at 3 years are 68% and 63%, respectively. Early chimerism analysis showed 67% of patients with complete chimerism (CC) in bone marrow (BM), 86% in peripheral blood (PB), 89% in granulocytes and 68% in T lymphocytes. On day +100, these figures were 68%, 79%, 90% and 73%, respectively, and on day +180 there were 83% patients with CC in BM, 100% in PB, 100% in granulocytes and 100% in T lymphocytes. We observed a trend to a higher incidence of relapse in patients with mixed chimerism (MC) as compared to patients with CC. MRD monitoring by flow cytometry and/or RT-PCR analysis was performed in 23 patients. MRD assessment on days +21 to +56 after transplant allowed identification of patients at risk of relapse. In this sense, seven out of 12 patients (58.3%) who had positive MRD on days +21 to +56 relapsed as compared to none out of 11 patients who had negative MRD (P = 0.002). Of the seven patients with criteria to monitor MRD who relapsed after transplant, all but one remained MRD positive until relapse. By contrast, 10 patients remained MRD negative and all of them are in continuous CR. In nine additional patients, persistence of MRD or mixed chimerism was observed after transplant and withdrawal of cyclosporin with or without DLI was performed. Only two out of these nine patients relapsed. MRD clearance was preceded by CC and GVHD. In conclusion, in our study we found that RIC allogeneic transplantation can be used in patients considered poor candidates for conventional transplantation due to advanced age or other concurrent medical conditions with both low toxicity and low transplant-related mortality. Simultaneous studies of both chimerism and MRD are a useful tool in order to predict risk of relapse in patients undergoing RIC transplants and so can be helpful for individualizing treatment strategies after transplant.

Chimerism analysis following allogeneic peripheral blood stem cell transplantation with reduced-intensity conditioning.

Summary:We have performed a prospective study to evaluate early chimerism and its kinetics after allogeneic peripheral blood stem cell transplantation among 68 patients who received a reduced-intensity conditioning (RIC) regimen with fludarabine plus melphalan (n=40) or busulphan (n=28). Chimerism was analyzed by polymerase chain reaction amplification of short tandem repeats in unfractionated (UF) and/or fractionated nucleated cells from bone marrow and peripheral blood (PB). All of the patients showed initial donor engraftment and no patient presented primary or secondary graft failure. In UF samples, the probability of achieving stable complete donor chimerism (CDC) in PB within the first 6 months was 70% on day +30, 85% on day +100 and 95% on day +180. CDC in granulocytes was observed in nearly all cases from day +30 onwards. CDC in T cells, however, differed among melphalan and busulphan recipients during the first 3 months (100 vs 0% on day +30 and 93 vs 20% on day +90, respectively). In multivariate analysis, the only significant variable associated with the achievement of early CDC was having received more than two lines of chemotherapy pretransplant (P<0.02). No correlation was found between the rate of achieving early CDC and the occurrence of acute graft-versus-host disease (GVHD) or disease progression post-transplant. In multivariate analysis, the only variable that influenced the incidence of disease progression post-transplant was the development of chronic extensive GVHD (P<0.05). In conclusion, a state of CDC is readily obtained within the first 6 months after our RIC protocols. Donor myeloid engraftment occurs rapidly in all cases, while early T-cell CDC is more common in more immunosuppressed hosts and, perhaps, in melphalan recipients.

Reduced-intensity conditioning allogeneic transplantation is associated with a high incidence of extramedullary relapses in multiple myeloma patients

Reduced-intensity conditioning allogeneic transplantation is associated with a high incidence of extramedullary relapses in multiple myeloma patients

Prognostic Factors of Chronic Graft-versus-Host Disease Following Allogeneic Peripheral Blood Stem Cell Transplantation: The National Institutes Health Scale Plus the Type of Onset Can Predict Survival Rates and the Duration of Immunosuppressive Therapy

Several grading systems have been developed in the bone marrow transplantation setting in attempts to predict survival in patients with chronic graft-versus-host disease (cGVHD). In this study, we evaluated the prognostic value of the National Institutes of Health (NIH) scoring system and investigated for any additional prognostic factors in a series of 171 patients undergoing peripheral blood stem cell transplantation (PBSCT) from matched related donors. The cumulative incidence of cGVHD was 70%; cumulative incidences of mild, moderate, and severe cGVHD were 29%, 42% and 28%, respectively. Overall, 68% of patients were free from immunosuppression 5 years after transplantation. Absence of previous acute GVHD (aGVHD; hazard ratio [HR] = 2; P = .004) and mild cGVHD (HR = 4.2; P = .007) increased the probability of being off immunosuppressive treatment by the last follow-up. Overall survival (OS) at 5 years was 52%. Severe cGVHD, according to the NIH scoring system (HR = 13.27; P = .001) adversely influenced outcome, whereas de novo onset (HR = 0.094; P = .003) had a more favorable impact on survival. The combination of both variables allowed us to identify 4 different subgroups of patients with OS of 82%, 70%, 50%, and 25%. Our findings indicate that the NIH scoring system has some prognostic value in patients undergoing PBSCT and, together with the type of onset, must be considered to predict the possible outcome of patients who develop cGVHD.

Clinical significance of CD34+ cell dose in long-term engraftment following autologous peripheral blood stem cell transplantation.

The number of CD34+ cells has been described as the best parameter for predicting the quality of engraftment in peripheral blood progenitor cell (PBPC) transplantation in the early post-transplant period. In this study we have determined the optimal number of CD34+cells in order to maintain engraftment in the long term in a series of 100 patients receiving autologous PBPC transplantation. Based on our previous experience on the speed of early hematopoietic recovery, four subgroups of patients were established: patients infused less than 0.75 × 106/kg CD34+ (n = 9), 0.75 to 1.25 (n = 24), 1.25 to 2.0 (n = 37) and more than 2.0 (n = 30). These groups were designated as low, intermediate-low, intermediate-high and high CD34 groups, respectively. Transitory loss of neutrophil engraftment was observed in 67%, 30%, 16% and 6% of patients in the four mentioned CD34 groups respectively, with statistically significant differences between the different groups. Significant differences were also observed between the low CD34 group and the rest of the groups as regards platelet and red blood cell transfusion requirements, fever episodes, days of hospitalization and antibiotic requirements throughout the first year. Our results show that the dose of CD34+ cells influences engraftment also in the late post-transplant period, and correlates with transfusion and antibiotic requirements, fever episodes and days of hospitalization during the first year post-transplant.

Cidofovir treatment of human polyomavirus-associated acute haemorrhagic cystitis

Abstract: We report the case of an 18‐year‐old patient who received an allogeneic bone marrow transplant from an HLA‐identical unrelated donor for a Ph+ acute lymphoblastic leukemia, in his third complete remission. Cyclophosphamide and busulfan were used as conditioning treatment. Acute graft‐versus‐host disease developed on day +9, and the response to adequate treatment (steroids) was favourable. On day +45 the patient developed an acute severe haemorhragic cystitis, and BK polyomavirus was demonstrated in urine samples using electron microscopy and polymerase chain reaction. Urinary symptoms did not improve in spite of palliative treatment, but a response was evident after 2 weeks of cidofovir treatment.

Haematopoietic damage persists 1 year after autologous peripheral blood stem cell transplantation.

In the present study we have used cell culture assays in order to assess the damage in the haematopoietic system 1 year after peripheral blood stem cell transplantation (PBSCT), and to establish at what level, haematopoietic progenitor cells (HPC) or stroma, this damage occurs. Thirty-one patients, nine breast cancer (BC), 17 non-Hodgkin lymphoma (NHL) and five Hodgkin disease (HD), who had received autologous PBSCT were included. Forty-eight normal subjects who had given informed consent were used as controls. Results were also compared with a matched group of patients (25 cases) prior to PBSCT. Progenitor cells were analysed using CFU-GM and plastic adherent delta (PΔ) assays. Long-term bone marrow cultures (LTBMC) in one and two stages were established. One year after transplant both the number of committed progenitor cells and the CFU-GM production in LTBMC were significantly reduced in the three groups of patients when compared with controls (P < 0.05 or P < 0.01). two-stage ltbmc experiments showed that the impairment in cfu-gm production was due to damage in both patients’ stroma and haematopoietic progenitor cells (hpc). all patients, except those with hd, showed a decreased stromal layer confluence (P < 0.05), with significant differences in cell composition as compared to normal bone marrow (P = 0.001). When all these variables were compared with pretransplant results, we observed that stroma formation was significantly lower after PBSCT (P < 0.05), while the number of progenitor cells analysed by the pδ assay was significantly increased (P < 0.05). we can conclude that even 1 year after pbsct, both the committed hpc and bm stroma remain damaged.

Antibiotic prophylaxis with meropenem after allogeneic stem cell transplantation

Summary:In the present study, we analyze the efficacy of prophylaxis with meropenem in patients receiving a matched related donor allogeneic transplant. In total, 38 patients were sequentially treated with meropenem starting on the day of the first febrile episode (n=17, group A) vs prophylactic meropenem starting on the first day with <500/mm3 granulocytes (n=21, group B), and maintained until resolution of fever or after granulocyte count >500/mm3. Of these, 16 (94%) patients in group A developed fever as compared to 16 (76%) in group B (P=0.02). While only one patient in group A did not require first-line antibiotherapy, there were seven (33%) in group B who did not require it (P=0.01) since fever lasted less than 72 h. In addition, 52% patients in group B did not require second-line antibiotics as compared to 11% among patients in group A (P=0.04). In multivariate analysis prophylaxis with meropenem (HR=2.83, 95% CI (1–8.02); P=0.04) and disease status at transplant (HR for early stage=0.15, 95% CI (0.04–0.62); P=0.04) significantly influenced the development of fever. In conclusion, the current pilot study suggests that the use of prophylaxis with meropenem during the period of neutropenia in patients undergoing allogeneic transplantation favorably affects the morbidity of the procedure by reducing febrile episodes.

Phase II clinical trial for the evaluation of bortezomib within the reduced intensity conditioning regimen (RIC) and post‐allogeneic transplantation for high‐risk myeloma patients

The current study was designed to assess the safety and efficacy of bortezomib in combination with fludarabine and melphalan as reduced intensity conditioning before allogeneic stem cell transplantation in patients with high risk multiple myeloma. Sixteen patients were evaluable. The median number of previous line of treatment was 3; all patients had relapsed following a prior autograft and 13 had previously received bortezomib. Fifteen of them either remained stable or improved disease status at day +100 post‐transplant, including 11 patients with active disease. More specifically, nine patients (56%) and five patients (31%) reached complete remission and partial response, respectively. 25% developed grade III acute graft‐versus‐host disease. The cumulative incidence of non‐relapse mortality, relapse and overall survival were 25%, 54% and 41%, respectively, at 3 years. Regarding the non‐haematological toxicity (grade>2), two patients developed peripheral neuropathy, two patients liver toxicity and 1 pulmonary toxicity early post‐transplant. The haematological toxicity was only observed during the first three cycles mostly related to low haemoglobin and platelet levels. The current trial is the first one evaluating the safety and efficacy of bortezomib as part of a reduced intensity conditioning regimen among patients with high risk multiple myeloma.

Cerebral toxoplasmosis and Guillain-Barré syndrome after allogeneic peripheral stem cell transplantation.

We report an unusual case of cerebral toxoplasmosis associated with Guillain‐Barré syndrome ( GBS) in a 25‐year‐old patient diagnosed with chronic myelogenous leukaemia ( CML), who underwent a mismatched allogeneic peripheral stem cell transplantation ( PSCT). On day +83 he started with fever, and 7 days later tremor, muscular weakness, diplopia, dysarthria, respiratory difficulty, and universal arreflexia appeared, compatible with GBS. As the patient had a positive cytomegalovirus ( CMV) antigenemia, this was the aetiology suspected for his neurologic findings, but specific treatment failed to improve his clinical situation, and he died on day +123. Necropsy demonstrated cerebral toxoplasmosis and axonal degeneration of nerve roots compatible with the axonal form of GBS. Interestingly, the polymerase chain reaction ( PCR) signal for Toxoplasma gondii in two different cerebrospinal fluid ( CSF) samples had been negative. In addition, this case showed unique magnetic resonance imaging ( MRI) abnormalities. We conclude that a negative PCR on CSF cannot exclude toxoplasmosis in a transplant patient, and we emphasise the importance of considering Toxoplasma as an aetiology of fever and neurological symptoms in the transplant setting.