Detection of minimal residual disease by real-time PCR can be used as a surrogate marker to evaluate the graft-versus-myeloma effect after allogeneic stem cell transplantation

Allogeneic stem cell transplantation (allo-SCT) is an effective and potentially curative treatment for some cases of multiple myeloma (MM). The curative efficacy of allo-SCT may be largely attributed to its immunological activity, the graft-versus-myeloma (GVM) effect. To evaluate the kinetics of residual myeloma cells, we analyzed the follow-up bone marrow samples of three MM patients by means of a real-time molecular assay. We identified a consistent correlation between onset of graft-versus-host disease and disease response. These data suggest that real-time molecular follow-up can be used to monitor the GVM effect and that it can be employed in the clinical setting to tailor post transplant immunomodulation.

High rate of remission and low rate of disease recurrence in patients with multiple myeloma allografted with PBSC from their HLA-identical sibling donors

A total of 30 multiple myeloma patients (M=23, F=7; age 31-55 years, median 48) were allografted with peripheral blood stem cells (PBSC) from HLA-identical siblings. Time to transplantation was 3-107 months (median 8). Prior chemotherapy lines varied from 1 to 6 (median 1). Four patients were in complete remission (CR), 11 in partial remission (PR), 13 were considered to be nonresponders, and two had progressive disease. Most were conditioned with busulfan-melphalan. PBSC were collected by apheresis after G-CSF or sequential GM-CSF and G-CSF. The patients were grafted with 4.4-24.1 x 10(6)/kg CD34+ (median 7.9) and 0.9-7.9 x 10(8)/kg CD3+ cells (median 2.3). GVHD prophylaxis was methotrexate-cyclosporine. Engraftment was complete and rapid. Grades II-IV acute GVHD (aGVHD) developed in 16 (53%), but was grade III-IV only in five (17%); chronic GVHD (cGVHD) developed in 17 out of the 24 evaluable patients (71%). A total of 18 patients (71%) attained CR after transplantation. TRM was 30% overall, 16% at 100 days. There was only one relapse. Overall survival and event-free survival at 73 months were 60% and 67%, respectively. PCR negativity for IgH-gene rearrangement occurred in all persistently CR patients studied. PBSC allograft can induce long remissions, because of profound suppression of the neoplastic clone that is probably linked to the antitumor effect of cGVHD.

Treatment-related mortality and graft-versus-leukemia activity after allogeneic stem cell transplantation for chronic lymphocytic leukemia using intensity-reduced conditioning

Allogeneic stem cell transplantation (SCT) using reduced-intensity conditioning (RIC) has potential to be a promising treatment of aggressive chronic lymphocytic leukemia (CLL). Since available clinical data obtained with this novel approach are very limited, we have performed a survey on this issue. Data of 77 patients were collected from 29 European Group for Blood and Marrow Transplantation centers. Median age was 54 (30-66) years, and the median number of previous chemotherapy regimens was 3 (0-8). HLA-identical sibling donors were used in 81% of the cases. Moderate conditioning regimens (mainly low-dose total body irradiation (TBI) or fludarabine-cyclophosphamide combinations) were administered to 56% of the patients, whereas the remainder received more intense conditioning consisting of fludarabine-busulfan or high-dose melphalan combinations. In 40% of the patients, in vivo T-cell depletion (TCD) with anti-thymocyte globulin or CAMPATH-1H was part of the conditioning regimen. Cumulative treatment-related mortality (TRM) was 18% (95% CI 9; 27) after 12 months. Complete chimerism as well as best response was not achieved immediately post-transplant but took a median of 3 months to develop. The 2-year probability of relapse was 31% (95% CI 18; 44), with no event occurring later than 12 months post transplant in the absence of TCD. With one exception, relapses were not observed after onset of chronic graft-versus-host disease. Event-free and overall survival at 24 months were 56% (95% CI 43; 69) and 72% (95% CI 61; 83), respectively. The median follow-up was 18 (1-44) months. Donor lymphocyte infusions or secondary transplants were performed in 19 patients with insufficient disease control and/or incomplete donor chimerism post-transplant, leading to a response in seven patients (37%). Preliminary multivariate analysis identified less than PR at transplant (hazard ratio (HR) 3.5; P&<0.01) and alternative donor (HR 3.1; P=0.02) as significant risk factors for relapse, whereas number of previous regimens >2 (HR 5.4; P=0.03), TBI (HR 2.5; P=0.05), and alternative donor (HR 2.3; P=0.08) were risk factors for survival. We conclude that RIC might favorably influence the outcome after allogeneic SCT for CLL by reducing TRM while preserving graft-versus leukemia activity.

Concurrent administration of high-dose chemotherapy and rituximab is a feasible and effective chemo/immunotherapy for patients with high-risk non-Hodgkin's lymphoma

The aim of this study was to investigate feasibility, tolerability and efficacy of rituximab-supplemented high-dose sequential chemotherapy (R-HDS) with peripheral blood progenitor cell autografting as frontline or salvage treatment in patients with advanced non-Hodgkin's lymphoma (NHL). Thirty-two patients have been treated: 14 at disease onset and 18 with relapsed or progressive disease. R-HDS regimens included six courses of rituximab. Rituximab was delivered either concurrently with high-dose chemotherapy to exploit the in vivo purging properties of the drug as well as at the end of the treatment plan to target minimal residual disease. All patients treated at disease onset completed their treatment with no life-threatening toxicity, while two toxic deaths due to severe bilateral pneumonia were observed among patients treated due to relapsed or refractory disease. Thirteen of 14 patients treated up-front achieved CR. Among pre-treated patients 10 of 18 achieved CR with better results in patients with relapsed (seven of eight) compared to progressive disease (three of 10). PCR analysis was carried out in indolent lymphoma patients: nine of nine follicular lymphomas and three of six CD5-positive NHL collected PCR-negative peripheral blood progenitor cell harvests. The results of this pilot study show that R-HDS is feasible and effective with acceptable toxicity when used at disease onset. In pre-treated patients this treatment also showed promising results, although the risk of severe infections needs to be considered.

Maspin and mammaglobin genes are specific markers for RT-PCR detection of minimal residual disease in patients with breast cancer

BACKGROUND

This study evaluates the specificity of some reverse-transcriptase polymerase chain reaction (RT-PCR) assays for the detection of residual tumor cells in breast cancer patients. The following markers have been analysed: carcinoembryonic antigen (CEA), cytokeratins (CK19 and CK20), polymorphic epithelial mucin (MUC-1), epidermal growth factor receptor (EGFR), maspin, and mammaglobin. RT-PCR was employed to detect breast cancer cells in peripheral blood (PB), bone marrow (BM), and stem cell leukoaphereses (PBPC).

PATIENTS AND METHODS

We evaluated the specificity of our RT-PCR assays on a panel of breast cancer specimens (n = 30), on PBPC in patients undergoing high-dose chemotherapy (n = 38), on BM (n = 7) and PB (n = 5) samples obtained from patients with breast cancer. Marrow cells, PB, and PBPC from normal subjects or hematological tumor patients were tested as negative controls.

RESULTS

Only maspin and mammaglobin met the criteria of sensitivity and specificity required for the detection of residual disease; they were expressed in 80% and 97% of breast cancer specimens, respectively, and not expressed in normal controls. CK19, CK20. EGFR, MUC-1, and CEA were sometimes expressed in normal blood cells and/or hematological tumors.

CONCLUSIONS

Our data support the notion that maspin and mammaglobin are useful markers for RT-PCR detection of minimal residual disease (MRD) in breast cancer patients, and that perspective clinical studies are needed to determine wether RT-PCR assays will be useful in assessing prognosis, tailoring therapy, or developing new strategies for ex vivo purging.

Prediction of gestational age by ultrasonic fetometry in llamas (Lama glama) and alpacas (Lama pacos)

Fetal biparietal diameter (BPD) and thorax height (TH) were measured by ultrasound during intrauterine growth in pregnant llamas (Lama glama) and alpacas (Lama pacos). The goal was to establish representative curves that allows estimation of gestational age (GA) from real-time ultrasonic measurements of these fetal structures at any stage of gestation. Llamas and alpacas were mated under controlled conditions. Ultrasound exams were conducted to determine pregnancy status 1 month later. Measurements of fetal BPD and TH were conducted from the second month of pregnancy until term. Observation and assessment of fetal TH was difficult during the last 3 months of pregnancy, specially in llamas. Regression curves were calculated from the data as a function of GA, with the best fit represented by the following equations: llama GA=(BPD-0.002399)43.02293,r=0.98,P<0.001; llama GA=(TH-0.07137)46.94485, r=0.95,P<0.001; alpaca GA=(BPD-0.11376)47.23287, r=0.98,P<0.001; alpaca GA=(TH-0.36436)52.87663, r=0.96,P<0.001, where GA was measured in days and BPD and TH in centimeters. Results indicate that ultrasonic measurement of these fetal biometric variables constitute a valuable tool to estimate GA at any stage of pregnancy in these domestic South American camelids.

Central nervous system relapse in a patient with mantle cell lymphoma in continuous clinical and molecular remission at six years since autografting

Although molecular remissions have been frequently observed and associated with low likelihood of relapse in some lymphoid tumours, they are seldom reported in mantle cell lymphoma (MCL). We performed PCR analysis of a MCL patient with central nervous system (CNS) relapse occurring 76 months after autologous transplantation. Molecular follow-up showed constant absence of PCR-detectable disease, even after the onset of relapse. These data indicate that isolated CNS relapse may occur even after several years of continuous remission and cannot be excluded based on a persistent pattern of molecular remission. However, the prolonged remission duration observed in this patient suggests that achieving PCR-negativity may also be of benefit for MCL patients.

A validated real-time quantitative PCR approach shows a correlation between tumor burden and successful ex vivo purging in follicular lymphoma patients

OBJECTIVE

Purging procedures are increasingly used to provide stem cell collections devoid of contaminating tumor cells. In follicle center lymphoma (FCL), most approaches eradicate polymerase chain reaction (PCR);-detectable disease in only a fraction of harvests undergoing ex vivo manipulation. In this study we evaluated whether there is a relationship between tumor burden of stem cell harvests and successful clearance of PCR-detectable disease following ex vivo manipulation.

MATERIALS AND METHODS

To address this issue, we developed a real-time PCR approach for quantitative measurement of tumor contamination using the bcl-2 rearrangement. Real-time PCR was used to evaluate the relationship between tumor burden of stem-cell harvests and purging effectiveness in PCR(+) samples derived from 10 FCL patients. Ex vivo purging was performed using the MaxSep cell separator (Baxter Immunotherapy, Deerfield, IL, USA).

RESULTS

Our real-time PCR method proved effective, sensitive, accurate, and reproducible. Four collections were successfully cleared of minimal residual disease (MRD) whereas six remained PCR(+). Real-time PCR showed that the four collections successfully cleared of MRD had a prepurging tumor burden significantly lower than those remaining PCR(+) (p = 0.04).

CONCLUSION

This study provides the first evidence that evaluation of tumor burden in stem-cell harvests by real-time PCR can predict the effectiveness of therapeutic intervention in non-Hodgkin's lymphoma. Based on these findings, we foresee a more widespread use of this technique to evaluate the impact of different therapeutic approaches in FCL.

High-dose mitoxantrone + melphalan (MITO/L-PAM) as conditioning regimen supported by peripheral blood progenitor cell (PBPC) autograft in 113 lymphoma patients: high tolerability with reversible cardiotoxicity

Hematological and extrahematological toxicity of high-dose (hd) mitoxantrone (MITO) and melphalan (L-PAM) as conditioning regimen prior to peripheral blood progenitor cell (PBPC) autograft was evaluated in 113 lymphoma patients (87 at disease onset). Autograft was the final part of a hd-sequential (HDS) chemotherapy program, including a debulkying phase (1-2 APO +/- 2 DHAP courses) and then sequential administration of hd-cyclophosphamide, methotrexate (or Ara-C) and etoposide, at 10 to 30 day intervals. Autograft phase included: (1) hd-MITO, given at 60 mg/m2 on day -5; (2) hd-L-PAM, given at 180 mg/m2 on day -2; (3) PBPC autograft, with a median of 11 x 10(6) CD34+/kg, or 70 x 10(4) CFU-GM/kg, on day 0. A rapid hematological recovery was observed in most patients, with ANC >500/microL and Plt >20,000/microl values reached at a median of 11 and 10 days since autograft, respectively. The good hemopoietic reconstitution allowed the delivery of consolidation radiotherapy (RT) to bulky sites in 53 out of 57 candidate patients, within 1 to 3 months following autograft; five of these patients required back-up PBPC re-infusion due to severe post-RT pancytopenia. Few severe infectious complications were recorded. There was one single fatal event due to severe pancytopenia following whole abdomen RT. Cardiac toxicity was evaluated as left ventricular ejection fraction (LVEF), monitored by cardiac radionuclide scan. LVEF prior to and after autograft was significantly reduced (median values: 55% vs 46%) in 58 evaluated patients; however, a significant increase to a median value of 50% was observed in 45 patients evaluated at 1 to 3 years since autograft. At a median follow-up of 3.6 years, 92 patients are alive, with a 7-year overall survival projection and 6.7-year failure-free survival projection of 77% and 69%, respectively. We conclude that a conditioning regimen with hd-MITOIL-PAM fits well within the HDS program. It implies good tolerability and reversible cardiotoxicity and it may have contributed to the good long-term outcome observed in this series of patients.

Overweight as an adverse prognostic factor for non-Hodgkin's lymphoma patients receiving high-dose chemotherapy and autograft

Despite detailed evaluation of disease-associated prognostic factors, little is known about the impact of overweight in autograft programs for non-Hodgkin's lymphoma (NHL) patients. In order to address this issue, 121 NHL patients were retrospectively evaluated. They had been upfront (92 patients) or in relapse (29 patients) and received high-dose sequential (HDS) chemotherapy including peripheral blood progenitor cell (PBPC) autograft. Body mass index (BMI) was calculated as weight in kilograms divided by the square of the height in meters; overweight was defined as BMI > or = 28. Univariate and multivariate analyses were used to determine the prognostic implication of overweight and other known prognostic indicators on overall (OS) and event-free (EFS) survival for the entire group and overweight and non-overweight (reference) subgroups. With a median follow-up of 3 years, the estimated 5-year OS and EFS for the entire group were 58% and 49%, respectively. Twenty-eight patients (23%) had BMI > or = 28. Their median OS and EFS were 2.2 and 1.4 years, respectively, whereas median OS and EFS for the reference group have not been reached, with a 5-year projection of 65 and 55%, respectively (P < 0.002). On multivariate analysis, the risk of death among overweight patients was 2.9 (CI, 1.3-6.2) times that of the reference group; using EFS as the end point, a similar association between overweight and survival was observed. In conclusion, in high-risk NHL patients undergoing intensive chemotherapy and PBPC autografting overweight is associated with a poorer outcome.

Long-term follow-up of advanced-stage low-grade lymphoma patients treated upfront with high-dose sequential chemotherapy and autograft

Long-term outcome, after first line intensified high-dose sequential (i-HDS) chemotherapy, was evaluated in 46 patients, aged < or =65 years, with advanced low-grade lymphoma. Seventeen patients had small lymphocytic lymphoma (SLL), 29 had follicular lymphoma (FL), 10 of them with histologic transformation. I-HDS included: (1) tumor debulking, by 2 APO+2 DHAP courses; (2) sequential administration of high-dose (hd) etoposide, methotrexate, and cyclophosphamide, followed by peripheral blood progenitor cell (PBPC) harvest; (3) hd-mitoxantrone + melphalan with PBPC autograft. Ten FL patients had their PBPC immunologically purged ex vivo. There were two treatment-related deaths; five FL patients had short-lasting response followed by disease progression, five SLL reached a stable PR; overall, 34 patients (74%) reached CR. At a median follow-up of 4.3 years, the estimated 9-year OS and EFS were 84% and 45%, respectively. No significant differences were observed in the OS among patients at low, intermediate or high IPI score, with an estimated OS projection of 95%, 78%, and 75%, respectively. FL had longer survival without evidence of residual disease (9-year EFS: 59%) as compared to SLL patients (8.8-year EFS: 17%); however, both groups had prolonged survival and no need of salvage treatment, as shown by the time to disease progression curve, projected to 66% and 62% for SLL and FL, respectively. The results indicate that hd-approach in low-grade lymphoma: (1) is associated with longer progression-free survival as compared to conventional therapies; (2) may imply higher tumor mass reduction in FL as compared to SLL patients; (3) offers long life expectancy, with potential survival benefits at least for patients at intermediate/high IPI score.

Clinical relevance of minimal residual disease monitoring in non-Hodgkin's lymphomas: a critical reappraisal of molecular strategies

Although current treatments can induce clinical complete remissions in the vast majority of patients with indolent lymphoma, most of them actually relapse, because of the persistence of residual tumor cells which are undetectable using conventional diagnostic procedures. Polymerase chain reaction (PCR)-based methods are increasingly used for minimal residual disease detection (MRD), and provide useful prognostic information. In this review, current approaches for MRD detection in indolent lymphomas are summarized. In addition, the prognostic aspects of molecular monitoring after transplantation procedures are discussed. The experience accumulated over the past decade shows that PCR analysis has a prognostic impact in several therapeutic programs including conventional and high-dose regimens. Major advantages coming from the introduction of molecular monitoring in clinical programs have been: (1) a rapid evaluation of the anti-tumor activity of innovative treatments; and (2) an early identification of patients with a high-risk of disease recurrence.

Negative immunomagnetic ex vivo purging combined with high-dose chemotherapy with peripheral blood progenitor cell autograft in follicular lymphoma patients: evidence for long-term clinical and molecular remissions

The feasibility and efficacy of a novel immunomagnetic ex vivo negative purging method was evaluated on peripheral blood progenitor cells (PBPC) from 13 non-Hodgkin's lymphoma patients (eight follicular, FL; three mantle cell, MCL; two FL with histologic transformation). A peculiar feature of the study was the collection of PBPC after prolonged tumor debulking. Our method included a stem cell enrichment phase followed by cell incubation with anti-B cell MoAbs (anti-CD19, CD20, CD22, CD23), addition of immunobeads, and then positive cell removal by passage on a Max-Sep (Baxter Immunotherapy) cell separator. Engraftment was rapid and stable. Hematological values were assessed 1 and 2 years after the autograft. Purging efficacy was molecularly assessed in a panel of 11 patients who showed persistence of PCR-detectable lymphoma cells on PBPC harvests despite intensified chemotherapeutic debulking. PCR-negativity was obtained in vitro and persisted in vivo after autograft in three FL patients; five more FL patients, whose purged PBPC were PCR+, converted to stable (3 patients) or fluctuating (two patients) PCR negativity after autograft. MCL patients never reached PCR negativity. Thus, ex vivo purging may have a role for FL patients harvesting PCR-positive PBPC after intensified chemotherapy. In contrast, the addition of ex vivo purging seems to be of little if any benefit for MCL patients.