Riikka Räty

Nordic MCL2 trial update: six-year follow-up after intensive immunochemotherapy for untreated mantle cell lymphoma followed by BEAM or BEAC + autologous stem-cell support: still very long survival but late relapses do occur

Mantle cell lymphoma (MCL) is a heterogenic non‐Hodgkin lymphoma entity, with a median survival of about 5 years. In 2008 we reported the early – based on the median observation time of 4 years – results of the Nordic Lymphoma Group MCL2 study of frontline intensive induction immunochemotherapy and autologous stem cell transplantation (ASCT), with more than 60% event‐free survival at 5 years, and no subsequent relapses reported. Here we present an update after a median observation time of 6·5 years. The overall results are still excellent, with median overall survival and response duration longer than 10 years, and a median event‐free survival of 7·4 years. However, six patients have now progressed later than 5 years after end of treatment. The international MCL Prognostic Index (MIPI) and Ki‐67‐expression were the only independent prognostic factors. Subdivided by the MIPI‐Biological Index (MIPI + Ki‐67, MIPI‐B), more than 70% of patients with low‐intermediate MIPI‐B were alive at 10 years, but only 23% of the patients with high MIPI‐B. These results, although highly encouraging regarding the majority of the patients, underline the need of a risk‐adapted treatment strategy for MCL. The study was registered at www.isrctn.org as ISRCTN 87866680.

The Mantle Cell Lymphoma International Prognostic Index (MIPI) is superior to the International Prognostic Index (IPI) in predicting survival following intensive first-line immunochemotherapy and autologous stem cell transplantation (ASCT)

Mantle cell lymphoma (MCL) has a heterogeneous clinical course. The recently proposed Mantle Cell Lymphoma International Prognostic Index (MIPI) predicted the survival of MCL better than the International Prognostic Index in MCL patients treated with conventional chemotherapy, but its validity in MCL treated with more intensive immunochemotherapy has been questioned. Applied here to 158 patients of the Nordic MCL2 trial of first-line intensive immunochemotherapy followed by high-dose chemotherapy and autologous stem cell transplantation, the MIPI and the simplified MIPI (s-MIPI) predicted survival significantly better (P < .001) than the International Prognostic Index (P > .004). Both the MIPI and the s-MIPI mainly identified 2 risk groups, low and intermediate versus high risk, with the more easily applied s-MIPI being just as powerful as the MIPI. The MIPI(B) (biological), incorporating Ki-67 expression, identified almost half of the patients as high risk. We suggest that also a simplified MIPI(B) is feasible.

Ki-67 expression level, histological subtype, and the International Prognostic Index as outcome predictors in mantle cell lymphoma

Abstract: Objectives : Mantle cell lymphoma (MCL) is characterised by translocation t(11;14) (q13;q32) leading to rearrangement of bcl1/CCND1 and overexpression of the cell‐cycle regulatory protein cyclin D1. We assessed the significance of the cell proliferation rate as an outcome predictor with the five components of the International Prognostic Index (IPI) and the histological subtypes of MCL. Patients and methods : The hospital case records and histopathological material of 127 patients diagnosed with MCL in a single centre were reviewed. The cell proliferation rate was assessed by Ki‐67 immunostaining and mitosis counting. Coxs multivariate regression model was used in multivariate survival analyses. The median follow‐up time was 87 months. Results : The mantle zone/nodular subtype of the common variant (19%) was associated with median survival of 70 months, the diffuse subtype of the common variant (64%) of 35 months, and the blastoid subtype (17%) of 11 months ( P  < 0.001). Patients with Ki‐67 expression in ≥ 26% (the upper tertile) of the lymphoma cells had median survival of only 13 months as compared with 45 months in the rest of the patients ( P  < 0.001). In a multivariate analysis high Ki‐67 expression, Ann Arbor stage III–IV, and age over 60 yr had independent influence on survival, whereas serum lactate dehydrogenase level, the number of extranodal disease sites, and performance status did not. Conclusions : The IPI may not be an optimal tool for outcome prediction in MCL, and a better prognostic index may be obtained by including Ki‐67 expression and possibly the histological subtype in the index.

Acute lymphoblastic leukemia in adolescents and young adults in Finland

Recent reports indicate that adolescents and young adults with acute lymphoblastic leukemia have a better outcome when treated with pediatric rather than adult therapeutic protocols. This Finnish study did not show any major difference between patients treated with pediatric protocols and those treated with adult protocols, but confirmed that adolescents and young adults with acute lymphoblastic leukemia still have a poorer outcome than children below 10 years of age. See related perspective article on page 1124. Background Interest has recently been paid to adolescents and young adults with acute lymphoblastic leukemia, particularly because all reports so far published indicate that these patients have a better outcome when treated with pediatric rather than adult therapeutic protocols. There are different biological subtypes of acute lymphoblastic leukemia with distinct features and prognoses; the distribution of these subtypes is not well known among adolescents. We, therefore, studied acute lymphoblastic leukemia in adolescents and young adults aged 10 to 25 years in Finland. Design and Methods This population-based study included 225 consecutive patients aged 10–25 years diagnosed with acute lymphoblastic leukemia during 1990–2004. One hundred and twenty-eight patients (10–16 years) were treated with pediatric Nordic (NOPHO) protocols, and 97 patients (17–25 years) with Finnish Leukemia Group National protocols. We characterized the biological subtypes, clinical features and outcome of these patients. Results For the whole cohort, the remission rate was 96%, 5-year event-free survival 62% and overall survival 72%.The 5-year event-free survival was 67% for the pediatric treatment group and 60% for the adult treatment group (p=n.s.). Patients with inferior outcome were those with a white bood cell count ≥ 100×109/L, the Philadelphia chromosome and MLL. Good prognostic features were TEL-AML1, hyperdiploidy, and pediatric intermediate risk stratification. Conclusions Unlike all previous studies, we found that the outcome of adolescents and young adults with acute lymphoblastic leukemia treated with pediatric or adult therapeutic protocols was comparable. The success of the adult acute lymphoblastic leukemia therapy emphasizes the benefit of central referral of patients to academic centers and adherence to research protocols. Key words: acute lymphoblastic leukemia, adolescents, survival, treatment outcome, young adults.

SOX11 and TP53 add prognostic information to MIPI in a homogenously treated cohort of mantle cell lymphoma – a Nordic Lymphoma Group study

Mantle cell lymphoma (MCL) is an aggressive B cell lymphoma, where survival has been remarkably improved by use of protocols including high dose cytarabine, rituximab and autologous stem cell transplantation, such as the Nordic MCL2/3 protocols. In 2008, a MCL international prognostic index (MIPI) was created to enable stratification of the clinical diverse MCL patients into three risk groups. So far, use of the MIPI in clinical routine has been limited, as it has been shown that it inadequately separates low and intermediate risk group patients. To improve outcome and minimize treatment‐related morbidity, additional parameters need to be evaluated to enable risk‐adapted treatment selection. We have investigated the individual prognostic role of the MIPI and molecular markers including SOX11, TP53 (p53), MKI67 (Ki‐67) and CCND1 (cyclin D1). Furthermore, we explored the possibility of creating an improved prognostic tool by combining the MIPI with information on molecular markers. SOX11 was shown to significantly add prognostic information to the MIPI, but in multivariate analysis TP53 was the only significant independent molecular marker. Based on these findings, we propose that TP53 and SOX11 should routinely be assessed and that a combined TP53/MIPI score may be used to guide treatment decisions.

Nordic MCL3 study: 90Y-ibritumomab-tiuxetan added to BEAM/C in non-CR patients before transplant in mantle cell lymphoma

The main objective of the MCL3 study was to improve outcome for patients not in complete remission (CR) before transplant by adding (90)Y-ibritumomab-tiuxetan (Zevalin) to the high-dose regimen. One hundred sixty untreated, stage II-IV mantle cell lymphoma patients <66 years received rituximab (R)-maxi-CHOP (cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisone) alternating with R-high-dose cytarabine (6 cycles total), followed by high-dose BEAM/C (bis-chloroethylnitrosourea, etoposide, cytarabine, and melphalan or cyclophosphamide) and autologous stem cell transplantation from 2005 to 2009. Zevalin (0.4 mCi/kg) was given to responders not in CR before transplant. Overall response rate pretransplant was 97%. The outcome did not differ from that of the historic control: the MCL2 trial with similar treatment except for Zevalin. Overall survival (OS), event-free survival (EFS), and progression-free survival (PFS) at 4 years were 78%, 62%, and 71%, respectively. For responding non-CR patients who received Zevalin, duration of response was shorter than for the CR group. Inferior PFS, EFS, and OS were predicted by positron emission tomography (PET) positivity pretransplant and detectable minimal residual disease (MRD) after transplant. In conclusion, positive PET and MRD were strong predictors of outcome. Intensification with Zevalin may be too late to improve the outcome of patients not in CR before transplant. This trial was registered at www.clinicaltrials.gov as #NCT00514475.

15-year follow-up of the Second Nordic Mantle Cell Lymphoma trial (MCL2) : Prolonged remissions without survival plateau

In recent decades, the prognosis of Mantle Cell Lymphoma (MCL) has been significantly improved by intensified first‐line regimens containing cytarabine, rituximab and consolidation with high‐dose‐therapy and autologous stem cell transplantation. One such strategy is the Nordic MCL2 regimen, developed by the Nordic Lymphoma Group. We here present the 15‐year updated results of the Nordic MCL2 study after a median follow‐up of 11·4 years: For all patients on an intent‐to‐treat basis, the median overall and progression‐free survival was 12·7 and 8·5 years, respectively. The MCL International Prognostic Index (MIPI), biological MIPI, including Ki67 expression (MIPI‐B) and the MIPI‐B including mIR‐18b expression (MIPI‐B‐miR), in particular, significantly divided patients into distinct risk groups. Despite very long response durations of the low and intermediate risk groups, we observed a continuous pattern of relapse and the survival curves never reached a plateau. In conclusion, despite half of the patients being still alive and 40% in first remission after more than 12 years, we still see an excess disease‐related mortality, even among patients experiencing long remissions. Even though we consider the Nordic regimen as a very good choice of regimen, we recommend inclusion in prospective studies to explore the benefit of novel agents in the frontline treatment of MCL.

Predictive factors for blastoid transformation in the common variant of mantle cell lymphoma

Approximately 20% of the mantle cell lymphoma (MCL) patients present with the blastoid variant at diagnosis. Blastoid changes may occur also during the course of the disease, but factors related to blastoid transformation are poorly understood. In the present study, the incidence and predictive factors for blastoid transformation were analysed among 52 patients who primarily had the common variant of MCL and one or more biopsies taken at the time of disease progression. Blastoid transformation occurred in 18 (35%) patients. The minimum estimated risk of transformation was 42% at 5 years of follow-up. At the time of transformation, all except two patients had systemic lymphoma with lymphatic blasts in the blood. The median survival time after blastoid transformation was 3.8 months compared with 26 months in patients without transformation (P<0.001). The respective survival times as calculated from the initial diagnosis of MCL were 31 and 60 months. Leucocytosis, an elevated serum lactate dehyrdogenase (LDH) level, and a high proliferative activity at diagnosis as assessed by the mitotic count and Ki-67 staining were associated with an increased risk of blastoid transformation, and elevated serum LDH and blood leucocytosis with a short time interval to transformation. We conclude that blastoid transformation is not uncommon during the course of MCL, and is associated with a poor outcome. An elevated serum LDH level, a high cell proliferation rate, and leucocytosis are predictive for a high risk of blastoid transformation in MCL.

Focal 9p instability in hematologic neoplasias revealed by comparative genomic hybridization and single‐nucleotide polymorphism microarray analyses

Copy number losses in chromosome arm 9p are well‐known aberrations in malignancies, including leukemias. The CDKN2A gene is suggested to play a key role in these aberrations. In this study overviewing 9p losses in hematologic neoplasias, we introduce the term focal 9p instability to indicate multiple areas of copy number loss or homozygous loss within a larger heterozygous one in 9p. We have used microarray comparative genomic hybridization to study patients with acute lymphoblastic leukemia (ALL, n = 140), acute myeloid leukemia (n = 50), chronic lymphocytic leukemia (n = 20), and myelodysplastic syndromes (n = 37). Our results show that 9p instability is restricted to ALL. In total, 58/140 (41%) patients with ALL had a loss in 9p. The 9p instability was detected in 19% of the patients with ALL and always included homozygous loss of CDKN2A along with loss of CDKN2B. Other possibly important genes included MTAP, IFN, MLLT3, JAK2, PTPLAD2, and PAX5. 13/27 (48%) patients with the instability had the BCR/ABL1 fusion gene or other oncogene‐activating translocation or structural aberrations. Two patients had homozygous loss of hsa‐mir −31, a microRNA known to regulate IKZF1. IKZF1 deletion at 7p12.1 was seen in 10 (37%) patients with the 9p instability. These findings suggest that, in ALL leukemogenesis, loss of CDKN2A and other target genes in the instability region is frequently associated with BCR/ABL1 and IKZF1 dysfunction. The multiple mechanisms leading to 9p instability including physical or epigenetic loss of the target genes, loss of the microRNA cluster, and the role of FRA9G fragile site are discussed.

TP53 mutations identify younger mantle cell lymphoma patients who do not benefit from intensive chemoimmunotherapy

Despite recent advances in lymphoma treatment, mantle cell lymphoma (MCL) remains incurable, and we are still unable to identify patients who will not benefit from the current standard of care. Here, we explore the prognostic value of recurrent genetic aberrations in diagnostic bone marrow (BM) specimens from 183 younger patients with MCL from the Nordic MCL2 and MCL3 trials, which represent current standard-of-care regimens. In the univariate model, mutations of TP53 (11%) and NOTCH1 (4%), and deletions of TP53 (16%) and CDKN2A (20%), were significantly associated with inferior outcomes (together with MIPI, MIPI-c, blastoid morphology, and Ki67 > 30%); however, in multivariate analyses, only TP53 mutations (HR, 6.2; P < .0001) retained prognostic impact for overall survival (OS), whereas TP53 mutations (HR, 6.9; P < .0001) and MIPI-c high-risk (HR, 2.6; P = .003) had independent prognostic impact on time to relapse. TP53-mutated cases had a dismal outcome, with a median OS of 1.8 years, and 50% relapsed at 1.0 years, compared to a median OS of 12.7 years for TP53-unmutated cases (P < .0001). TP53 mutations were significantly associated with Ki67 > 30%, blastoid morphology, MIPI high-risk, and inferior responses to both induction- and high-dose chemotherapy. In conclusion, we show that TP53 mutations identify a phenotypically distinct and highly aggressive form of MCL with poor or no response to regimens including cytarabine, rituximab, and autologous stem-cell transplant (ASCT). We suggest patients with MCL should be stratified according to TP53 status, and that patients with TP53 mutations should be considered for experimental frontline trials exploring novel agents.