Maria Christina Cox

The kinetics of reduction of minimal residual disease impacts on duration of response and survival of patients with acute myeloid leukemia

We assessed by multiparametric flow cytometry the levels of minimal residual disease (MRD) in 100 adult patients with acute myelogenous leukemia (AML) achieving complete remission after intensive chemotherapy. The aim of the study was to determine the optimal threshold, in terms of residual leukemic cells, and the time point of choice, that is, post-induction (post-Ind) or post-consolidation (post-Cons), able to better predict outcome. By applying the maximally selected log-rank statistics, the threshold discriminating MRD− from MRD+ cases was set at 3.5 × 10−4 residual leukemic cells, a level that allowed the identification of distinct subgroups of patients, both at post-Ind and post-Cons time points. Post-Cons MRD− patients had a superior outcome in terms of relapse rate, overall survival (OS) and relapse-free survival (RFS) (P<0.001, for all comparisons), regardless of the MRD status after induction. In particular, patients entering MRD negativity only after consolidation showed the same outcome as those achieving early negativity after induction. Multivariate analysis, including karyotype, age, MDR1 phenotype, post-Ind and post-Cons MRD levels, indicated that the post-Cons MRD status independently affected relapse rate, OS and RFS (P<0.001, for all comparisons). In conclusion: (1) the threshold of 3.5 × 10−4 is valid in discriminating risk categories in adult AML and (2) post-Cons MRD assessment is critical to predict disease outcome.

Low absolute lymphocyte count is a poor prognostic factor in diffuse-large-B-cell-lymphoma

The prognostic value of absolute lymphocytic count (ALC), has been a recent matter of debate in non-Hodgkin-lymphoma (NHL). We assessed prospectively the value of ALC at diagnosis and also after the completion of immuno-chemotherapy in 101 diffuse-large-B-cell-lymphoma (DLBCL). Analysis of prognostic factors with respect to overall survival (OS), event free survival (EFS) and progression free survival (PFS) was done by two-tailed log-rank test. The ALC cut-off value was calculated as <0.84 × 109/L at diagnosis: this was a strong negative prognostic factor for OS (p = 0.0004), EFS (p < 0.00001) and PFS (p < 0.00001) and in multivariate analysis was independent from the revised-international-prognostic-index (R-IPI). ALC after chemo-immunotherapy was not of prognostic value. As R-IPI and ALC < 0.84 × 109/L, were the factors better discriminating poor prognosis, a new trichotomous score (ALC/R-IPI) was built up: (1) low risk: R-IPI = very good or good and ALC < 0.84 × 109/L; (2) intermediate risk: patients with at least one risk factor (R-IPI = poor or ALC < 0.84 × 109/L). (3) high risk: patients with both risk factors. This new prognostic score was highly significant in univariate analysis for OS (p = 0.0002), EFS (p < 0.00001) and PFS (p < 0.00001). In multivariate analysis ALC/R-IPI was the most predictive factor for OS (OR = 2.954; p = 0.002) and EFS (OR = 2.381; p < 0.00001) and the only predictive factor for PFS (OR = 4.018; p < 0.00001).Our data, show that ALC at diagnosis has a strong prognostic relevance and is independent from the R-IPI. The new score including both values proved the most powerful predictor at multivariate analysis.

The prognostic value of cytogenetics is reinforced by the kind of induction/consolidation therapy in influencing the outcome of acute myeloid leukemia - Analysis of 848 patients

We studied the impact of cytogenetics and kind of induction/consolidation therapy on 848 adult acute myeloid leukemia (AML) patients (age 15–83). The patients received three types of induction/consolidation regimen: standard (daunorubicin and cytosine arabinoside (3/7); two cycles); intensive (idarubicin, cytosine arabinoside and etoposide (ICE), plus mitoxantrone and intermediate-dose Ara-C (NOVIA)); and low-dose (low-dose cytosine arabinoside). CR patients under 60 years of age, if an HLA-identical donor was available received allogeneic stem cell transplantation (allo-SCT); otherwise, as part of the program, they underwent autologous (auto)-SCT. CR rates significantly associated with ‘favorable’ (inv(16), t(8;21)), ‘intermediate’ (‘no abnormality’, abn(11q23), +8, del(7q)) and ‘unfavorable’ (del (5q), −7, abn(3)(q21q26), t(6;9), ‘complex’ (more than three unrelated cytogenetic abnormalities)) karyotypes (88% vs65% vs 36%, respectively; P = 0.0001). these trends were confirmed in all age groups. on therapeutic grounds, intensive induction did not determine significant increases of cr rates in any of the considered groups, with respect to standard induction. low-dose induction was associated with significantly lower cr rates. considering disease-free survival (dfs), multivariate analysis of the factors examined (including karyotype grouping) showed that only age >60 years significantly affected outcome. However, in cases where intensive induction was adopted, ‘favorable’ karyotype was significantly related to longer DFS (P = 0.04). This was mainly due to the favorable outcome of t(8;21) patients treated with intensive induction. Patients receiving allo-SCT had significantly longer DFS (P = 0.005); in particular, allo-SCT significantly improved DFS in the ‘favorable’ and ‘intermediate’ groups (P = 0.04 and P = 0.048, respectively). In conclusion our study could provide some guidelines for AML therapy: (1) patients in the ‘favorable’ karyotype group seem to have a longer DFS when treated with an intensive induction/consolidation regimen, adopted before auto-SCT instead of standard induction; this underlines the importance of reinforcement of chemotherapy, not necessarily based on repeated high-dose AraC cycles. Allo-SCT, independently of induction/consolidation therapy, should be considered an alternative treatment; (2) patients in the ‘intermediate’ karyotype group should receive allo-SCT; (3) patients in the ‘unfavorable’ karyotype group should be treated using investigational chemotherapy, considering that even allo-SCT cannot provide a significantly longer DFS, but only a trend to a better prognosis.

Prognostic models for diffuse large B-cell lymphoma in the rituximab era: a never-ending story

BACKGROUND Improved treatment have modified survival outcome in patients with diffuse large B-cell lymphoma (DLBCL) and altered the importance of previously recognized prognostic markers. DESIGN AND METHODS To evaluate International Prognostic Index (IPI) score before and after rituximab introduction and to validate the absolute lymphocyte count (ALC)/revised International Prognostic Index (R-IPI) model, we carried out a retrospective analysis on a total of 831 patients with DLBCL. RESULTS Our results show that IPI lost its discriminating power with the introduction of rituximab. The analysis of our second set allowed us to validate the ALC/R-IPI model. The R-IPI and ALC/R-IPI could still be used for designing clinical trials, but both have difficulty recognizing a high percentage of poor prognosis patients, though it remains an important goal of a good prognostic model considering the modest impact of salvage treatments on survival. CONCLUSIONS A new model on the basis of significant variables in the rituximab era and built on a large database of patients treated with rituximab is urgently needed. As prognostic models are changing with the efficacy and mechanisms of action of treatment utilized, looking for a new prognostic score is a never-ending story in which researchers are trying to hit a continuously moving target.

Monocyte count at diagnosis is a prognostic parameter in diffuse large B-cell lymphoma: results from a large multicenter study involving 1191 patients in the pre- and post-rituximab era

In this study we assessed the prognostic significance of absolute monocyte count and selected the best cut-off value at diagnosis in a large cohort of patients with diffuse large B-cell lymphoma. Data were retrieved for therapy-naïve patients with diffuse large B-cell lymphoma followed in Israel and Italy during 1993–2010. A final cohort of 1017 patients was analyzed with a median follow up of 48 months and a 5-year overall survival rate of 68%. The best absolute monocyte count cut-off level was 630/mm3 and the 5-year overall survival for patients with counts below this cut-off was 71%, whereas it was 59% for those with a count >630 mm3 (P=0.0002). Of the 1017 patients, 521 (51%) were treated with chemo-immunotherapy, and in this cohort, using multivariate analysis, elevated monocyte count retained a negative prognostic value even when adjusted for International Prognostic Index (HR1.54, P=0.009). This large study shows that a simple parameter such as absolute monocyte count (>630/mm3) can easily be used routinely in the evaluation of newly diagnosed diffuse large B-cell lymphoma to identify high-risk patients with a worse survival in the rituximab era.

Efficacy and safety of bendamustine for the treatment of patients with recurring Hodgkin lymphoma

The management of patients with Hodgkin lymphoma (HL) recurring after stem cell transplantation (SCT) and multiply relapsed disease remains challenging. We report on 41 such patients who received bendamustine hydrochloride, a bifunctional mechlorethamine derivative mechanistically unrelated to traditional alkylators, after a median of four prior chemotherapy lines, including SCT in 85% of cases. Bendamustine was given at doses of 90–120 mg/m2 every 21 or 28 d. At first assessment (2–4 cycles), the overall response rate (ORR) was 78% with 12 (29%) complete (CR) and 20 (49%) partial responses (PR). Upon treatment prolongation to 6–8 courses, 40% of PRs progressed, yielding a final ORR of 58% with 31% of CRs. Eight patients (two CRs, six PRs) were subsequently allotransplanted. Median progression‐free and overall survival exceeded 11 and 21 months respectively; complete responders displayed a median disease‐free survival above 9 months with a relapse rate of only 30%. Outcomes were independent of disease chemosensitivity, previous transplant and bendamustine dose‐intensity. No life‐threatening or unexpected adverse events occurred. Within the limits of a retrospective analysis and schedule heterogeneity, these results appear very encouraging and prompt prospective trials to confirm bendamustine as a valuable option in the palliative setting and in cytoreductive strategies before allotransplantation.

P-glycoprotein and terminal transferase expression identify prognostic subsets within cytogenetic risk classes in acute myeloid leukemia

Clinical and biological features were assessed in 204 consecutive de novo adult acute myeloid leukemia (AML) patients who received intensive chemotherapy regimens. Multiparameter flow cytometric assays both of the multidrug resistance (MDR-1)-associated P-glycoprotein (PGP) using the UIC2 monoclonal antibody (MoAb), and of terminal transferase (TdT) were performed. Cytogenetic findings were obtained from 196 patients with high resolution banding. At onset, UIC2 and TdT positivities were detected in 58.5% and 24% of cases, respectively. There were strict correlations either between UIC2 negativity and FAB M3 or between TdT and FAB M0-M1 (P = 0.001 and < 0.0001, respectively). On the other hand, age was significantly associated with cytogenetic risk classes (P < 0.0001). CD34 positivity was highly correlated with TdT expression (P < 0.0001). Moreover, CD7 and CD11b were significantly represented in UIC2+ subset (P < 0.0001). Rhodamine 123 (Rh 123) efflux was significantly higher in 75 UIC2 positive patients compared to 65 UIC2 negative ones (P < 0.001). As regards to cytogenetics, TdT positivity was strongly related either to t(9;22) or single/associated anomalies of chromosome 7; on the other hand, most or all cases with t(8;21) or t(15;17) were UIC2 or TdT negative, respectively. The rate of first complete remission (CR) differed both between UIC2+ and UIC2- cases and between TdT+ and TdT- ones (40% versus 72%, P < 0.001; and 36% versus 61%, P = 0.001, respectively). The survival rates (Kaplan-Meier method) were significantly shorter either in UIC2+ or in TdT+ patients (P = 0.005 and = 0.011, respectively). UIC2 and TdT negative cases showed longer remission duration (P = 0.03 and = 0.22, respectively). The additional effect of UIC2 and TdT on prognosis allowed us to identify two subsets of patients, the first [UIC2- TdT-] at better and the second [UIC2+ TdT+] at worse clinical outcome compared to single UIC2 and TdT cases, concerning CR (P < 0.001), survival (P < 0.0001) and CR duration (P = 0.007). The combinations [UIC2+ TdT-] and [UIC2- TdT+] showed an intermediate clinical course. A strong difference was found between poor risk and intermediate/favorable risk cytogenetic classes with regard to CR rate (P < 0.0001), overall survival and CR duration (P < 0.001). Nevertheless, within the poor risk class, UIC2 positivity was able to identify patients at worst prognosis with regard to CR (P = 0.005), survival (P = 0.02) and CR duration (P = 0.015). On the other hand, UIC2 and TdT negativity allowed us to distinguish patients with longer survival (P = 0.012 and = 0.04, respectively) and CR duration (P = 0.04 and = 0.025, respectively) within the intermediate/favorable risk class. The independent prognostic value of UIC2, TdT and cytogenetic risk classes was confirmed in multivariate analysis. These results suggest that PGP and TdT expressions, together with cytogenetic findings, may represent a basic predictor of chemotherapeutic failure in AML.

P-glycoprotein and BCL-2 levels predict outcome in adult acute lymphoblastic leukaemia

Summary. Concurrent resistance mechanisms, such as P‐glycoprotein (PGP) and bcl‐2, may contribute to a worse outcome in adult acute lymphoblastic leukaemia (ALL). Between 1990 and 2000, we analysed PGP and bcl‐2 by flow cytometry, using two anti‐PGP (C219 and JSB‐1) monoclonal antibodies (mAbs) and an anti‐bcl‐2 mAb in 115 de novo adult ALL patients. Both a longer overall survival (OS) and longer disease‐free survival (DFS) were observed in PGP‐negative patients (23%vs 0% at 3 years, P = 0·011 and 29%vs 0% at 2 years, P = 0·006 for C219 respectively; 42%vs 0% at 1·5 years, P = 0·004 and 53%vs 0% at 8·5 months, P = 0·00006 for JSB‐1 respectively). Bcl‐2 positivity was associated with a significantly higher complete remission rate (90%vs 66%, P = 0·01). Moreover, in 69 patients not presenting with either t(9;22) or B‐mature immunophenotype, PGP negativity (JSB‐1) maintained its significant favourable prognostic impact with regard to OS (41%vs 0% at 1·5 years, P = 0·009) and DFS (83%vs 0% at 6 months, P = 0·0005). Importantly, within a subset of 62 patients with normal (n = 31) or unknown (n = 31) karyotype, PGP (JSB‐1)‐negative patients showed both a significantly longer OS and DFS (63%vs 0% at 1·4 years, P = 0·018 and 84%vs 0% at 6 months, P = 0·001 respectively). In multivariate analysis, JSB‐1 (P = 0·008) and cytogenetics (P = 0·02) were found to be independent prognostic factors with regard to DFS. Therefore, in adult ALL, PGP and bcl‐2 represent sensitive indicators of clinical outcome, and potential targets of novel molecules aimed at overcoming chemoresistance and recurrent relapses.

CD90/Thy-1 is preferentially expressed on blast cells of high risk acute myeloid leukaemias*

Different transformation mechanisms have been proposed for elderly acute myeloid leukaemia (AML) and secondary AML (sAML) when compared with de novo AML or AML of younger patients. However, little is known regarding differences in the immunophenotypic profile of blast cells in these diseases. We systematically analysed, by flow cytometry, 148 patients affected by de novo (100 cases) or sAML (48 cases). By defining a cut‐off level of 20% of CD34+ cells co‐expressing CD90, the frequency of CD90+ cases was higher in sAML (40%) versusde novo AML (6%, P < 0·001), elderly AML (>60 years) (24%) versus AML of younger patients (10%, P = 0·010) and poor‐ versus good‐risk karyotypes (according to the Medical Research Council classification, P < 0·001). The correlation between CD90 expression, sAML and unfavourable karyotypes was confirmed by analysing the subset of CD34+ AML cases alone (91/148). Consistently, univariate analysis showed that expression of CD90 was statistically relevant in predicting a shorter survival in CD90+ AML patients (P = 0·042). Our results, demonstrating CD90 expression in AML with unfavourable clinical and biological features, suggest an origin of these diseases from a CD90‐expressing haemopoietic progenitor and indicate the use of CD90 as an additional marker of prognostic value in AML.

Natural killer (NK) cells and anti-tumor therapeutic mAb: unexplored interactions

Tumor‐targeting mAb are widely used in the treatment of a variety of solid and hematopoietic tumors and represent the first immunotherapeutic approach successfully arrived to the clinic. Nevertheless, the role of distinct immune mechanisms in contributing to their therapeutic efficacy is not completely understood and may vary depending on tumor‐ or antigen/antibody‐dependent characteristics. Availability of next‐generation, engineered, tumor‐targeting mAb, optimized in their capability to recruit selected immune effectors, re‐enforces the need for a deeper understanding of the mechanisms underlying anti‐tumor mAb functionality. NK cells participate with a major role to innate anti‐tumor responses, by exerting cytotoxic activity and producing a vast array of cytokines. As the CD16 (low‐affinity FcγRIIIA)‐activating receptor is expressed on the majority of NK cells, its effector functions can be ideally recruited against therapeutic mAb‐opsonized tumor cells. The exact role of NK cells in determining therapeutic efficacy of tumor‐targeting mAb is still unclear and much sought after. This knowledge will be instrumental to design innovative combination schemes with newly validated immunomodulatory agents. We will summarize what is known about the role of NK cells in therapeutic anti‐tumor mAb therapy, with particular emphasis on RTX chimeric anti‐CD20 mAb, the first one used in clinical practice for treating B cell malignancies.