ALBERT

Description: Introduction. Patients with CLL and FISH positive for trisomy 12 (+12) have unique clinical and biological features. We, therefore, performed an analysis of the association between demographic, clinical, laboratoristic and biological features and outcomes in treatment-naive patients with +12 CLL. Methods. This study included 312 treatment-naive patients with +12 CLL from 9 centers. These patients, diagnosed between January 2000 and July 2016, were compared to a control group of 580 treatment-naive patients with FISH negative CLL, matched by age and gender and followed in the same centers. An additional cohort of 250 patients with +12 CLL followed at a single US institution was used as external validation. Results. Patients' baseline characteristics are shown in Table 1. As compared to patients with negative FISH, patients with +12 had a significant higher prevalence of elevated LDH (p

Description: Abstract 3562 Aim of the present study was to evaluate the clinical outcome of a large series of younger patients with symptomatic multiple myeloma (MM) who were enrolled in two subsequent clinical trials of thalidomide-dexamethasone (thal-dex) incorporated into double autologous stem-cell transplantation (ASCT) to support high-dose melphalan (200 mg/m2). In both studies, thal (100 mg/day for the first 14 days and then 200 mg/day) and pulsed dex (between 480 and 160 mg per cycle), were administered from the onset until the second ASCT. The analysis was performed on an intention-to-treat basis on a total of 593 patients who were followed for a median of 36 months. The best VGPR and CR rates were 69% and 35%, respectively. The median duration of CR was 66 months. Median TTP and PFS were 53 and 44 months, respectively. The 5-year projected rates of TTP and PFS were 46% and 38%, respectively, while the corresponding value for OS was 67%. More than 80% of the patients were screened at diagnosis for the presence of cytogenetic abnormalities by FISH analysis. Forty-five percent of patients had del(13q), while t(4;14) and del(17p) were found in 16 % and 7 % of patients, respectively. The presence of del(17p) and/or t(4;14) was associated with a significantly shorter 5-year projected TTP, PFS and OS in comparison with the absence of these abnormalities, indifferently from the presence or absence of del(13q) (TTP: 30% vs 53%, respectively P=0.0000; PFS: 28% vs 45%, respectively, P=0.0000; OS: 53% vs 69%, respectively, P=0.0000). OS and PFS curves of patients carrying del(13q) alone were almost superimposable to those of patients without cytogenetic abnormalities, while TTP was significantly shorter for patients with del(13q) alone (5-year projected rates: 40% vs 53%, respectively, P=0.04). Patients carrying del(17p) in the absence of t(4;14) had similar 5-year projected TTP and PFS as compared with t(4;14) positive but del(17p) negative patients. However, OS was significantly shorter for the subgroup with del(17p) and absence of t(4;14) in comparison with that of patients carrying t(4;14) without del(17p) (5 year projected rates: 18% vs 70%, respectively, P=0.03). In a multivariate analysis, presence of del(17p) and high beta2-m at baseline were the most important variables adversely influencing TTP (HR: 2.3, P=0.001 and HR: 1.8, P=0.002, respectively), PFS (HR: 2.0, P=0.001 and HR: 1.9, P=0.001, respectively), and OS (HR: 3.9, P=0.000 and HR: 2.0, P=0.005, respectively). Additional variables predicting for shorter TTP and PFS were the presence of t(4;14) (HR: 1.8, P=0.004) and of del(13q) (HR: 1.6, P= 0.009). Also the quality of best response to the overall treatment program influenced clinical outcomes. In particular, patients achieving CR had a significantly longer PFS and OS than those achieving a VGPR (PFS: median 68 vs 40 months, respectively, P=0.007; 5-year projected OS rates: 84% vs 70%, respectively, P=0.01). In conclusion, incorporation of thal-dex into double autotransplantation failed to overcome the poor prognosis conferred by del(13 q), t(4;14) and del(17p). In a multivariate Cox regression analysis, del(17p) and high levels of serum beta2-m at diagnosis were the strongest variables adversely influencing PFS and OS. In comparison with the presence of t(4;14) but absence of del(17p), patients carrying del(17p) without t(4;14) had a significantly shorter OS, possibly due to their worst outcome after relapse. Presence of del(13q) alone conferred a significantly shorter TTP, but did not have an adverse impact on OS due to the favorable role of effective salvage therapies incorporating either bortezomib or lenalidomide. Disclosures: Off Label Use: use of first line thalidomide in preparation for ASCT. Cavo:Janssen-Cilag: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau, no; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, no; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau, no.

Description: Background. High rates of response and minimal residual disease (MRD) negativity have been reported with the use of novel treatment options in multiple myeloma (MM) patients (pts) eligible for autologous stem-cell transplantation (ASCT). Despite very promising results, there is still a proportion of pts who do not respond to therapy or relapse early. This represents an unmet medical need. Aim. To identify the main factors predictive of early relapse in the context of novel treatment approaches. Methods. Data from newly diagnosed MM (NDMM) pts ≤65 years enrolled in the FORTE trial were analyzed. The evaluated baseline standard clinical and biological features included: age, Hb, creatinine, tumor circulating plasma cells (PCpb) evaluated by flow cytometry, bone marrow plasma cells (PCbm) evaluated as continuous variables, free light chain (L vs K), M-component subtype (IgA vs others), Revised International Staging System (R-ISS II/III vs I), LDH (〉ULN vs ≤ULN), ISS (III vs II vs I), presence vs absence of chromosomal abnormalities detected by FISH [(del17p, t(4;14), t(14;16), t(11;14), amp1q, del1p, del13], and presence vs absence of plasmacytomas. Pts were randomized to receive carfilzomib, lenalidomide, dexamethasone (KRd) induction - ASCT intensification - KRd consolidation (arm A); KRd12 (arm B); and carfilzomib, cyclophosphamide, dexamethasone (KCd) induction - ASCT intensification - KCd consolidation (arm C). Thereafter, patients were randomized to maintenance with lenalidomide alone or lenalidomide plus carfilzomib. Pre-maintenance MRD evaluation was performed by 8-color second generation flow cytometry (sensitivity 10-5) in patients who achieved at least a very good partial response (VGPR). Early relapse was defined as relapse ≤18 months from randomization. Univariate feature selection was performed between both categorical and continuous baseline variables and the achievement of pre-maintenance MRD negativity, according to Chi-square and Kruskal tests. The same baseline features, plus the achievement of MRD negativity, were included in a univariate analysis to select candidate predictors of early relapse. Selected features were then included in a multivariate logistic model. A multivariate analysis was performed to evaluate predictors of MRD negativity and early relapse. The model was adjusted for age and administered therapy. Results. 474 patients were enrolled in the trial. Baseline features were well balanced in the 3 arms. Predictors of MRD negativity (10-5): In univariate analysis, the baseline factors selected basing on the probability of achieving pre-maintenance MRD negativity were creatinine levels, ISS stage, R-ISS stage, del17p, PCbm (P=0.004) and PCpb. In multivariate analysis, including single variables not aggregated in R-ISS, increased creatinine levels (OR 0.48, 95% CI 0.25-0.94, P=0.03), increased PCbm (OR 0.95, 95% CI 0.91-0.99, P=0.01) and presence of del17p (OR 0.44, 95% CI 0.23-0.83, P=0.01) reduced the probability of achieving MRD negativity (Table). Predictors of early relapse: In univariate analysis, the main baseline factors selected basing on the risk of early relapse were LDH, ISS, R-ISS, PCbm, PCpb, del17p and achievement of MRD negativity. In multivariate analysis, R-ISS II/III vs I (OR 3.7, 95% CI 1.24-11, P

Description: Abstract 1454 Deletion 13q14 (13q-) detected by fluorescence in situ hybridization (FISH) is the most frequent chromosomal abnormality in chronic lymphocytic leukemia (CLL). When 13q- is detected as sole abnormality has a good prognosis, while aggressive outcome is registered when 13q- is combined with other chromosomal abnormalities such as del 11q or del 17p. A recent study evidenced also that patients with higher percentage of 13q-deleted cells (〉70%) are at higher risk for aggressive disease. Some studies evidenced that 13q- deletion size (involving D13S319 +/−Rb1) seems to matter in terms of time to treatment (TTT) and prognosis (OS). Few studies evaluated so far the incidence and prognosis of a biallelic 13q- deletion, i.e. the deletion of both alleles of the minimal deleted region (MDR) of chromosome 13q.In particular prognosis has been reported controversial. We analyzed at single institution 250 CLL patients by FISH in order to evaluate the incidence and prognosis of biallelic 13q- by using probes for D13S319 and RB1 that map to DLEU2/MIR15A/MIR16-1 and RB1 loci. Results were correlated in terms of TTT and OS with IGHV mutational status (mutated vs unmutated), RAI/BINET stage, CD38 positivity and/ or ZAP-70 positivity, beta-2M, LDH, other chromosomal abnormality (+12, del17p, del11q). Deletion 13q was considered present if 〉10% of nuclei were deleted out of 300 nuclei scored by two different and independent observers. All biallelic cases were confirmed by FISH using a probe for LSI-D13S319 and 13q34 to exclude false positive results. 135/250 (52%) patients presented a monoallelic del 13q. 45/135 (32%) presented a monoallelic del of RB1 while 20/135 (15%) cases presented a biallelic 13q-.12/20 (80%) presented a biallelic 13q- as sole abnormality, while 8/20 presented a 13q- associated with other cytogenetic abnormalities (one 17p-, five 11q-, two +12). The median percentage of 13q-deleted cells was 50% (range 14–86). Median age was 65 (range 50–85), M/F 12/8; 80% of the patients were RAI stage 0–1, while only 10% were RAI stage 4. No differences were seen in patients with biallelic deletion of 13q when LDH, b2M, ZAP-70,IGHV were considered. CD38 was negative in 16/20 patients. Regarding the MDR of chromosome 13q, 11/20 patients presented a biallelic del of D13S319, while 5/20 had a biallelic deletion of RB1; 5/20 patients presented a mono+biallelic del of D13S319 while 3/20 a mono+biallelic deletion of RB1. When we analyzed clinical and biological characteristics comparing patients with biallelic13q-,monoallelic 13q- and with no 13q-, we did not find differences in terms of: stage (RAI-Binet), P=0.2,P=0.9; B2 M, P=0.4; LDH,P=0.1; CD38 positivity, P=0.2; ZAP-70, P=0,1; IGHV M vs UM,P=0.65; P53 mutated vs wild type, P=0.1; del 11q was significantly associated more with biallelic 13q-, P=0.02. TTT and OS were not significantly different between biallelic 13q- patients and the other two groups (164 vs 212 vs 211, P=0.9). 8/20 patients with biallelic 13q- have been treated, all 5 patients carrying also a 11q- received treatment, the other 3 patients had: 1patient RB1 deletion in 92% of cells and 2 deletion 13q- in〉75% of cells. In conclusion, biallelic 13q- are present in about 8% of all cases of CLL and in 15% of 13q- patients. A strong association with del 11q was found and this correlated with disease progression and treatment.CD38 was negative in the majority of patients with biallelic 13q-. RB1 was deleted in 32% of 13q- patients. No differences were found in terms of clinical characteristics, TTT and OS with monoallelic 13q-. Disclosures: No relevant conflicts of interest to declare.

Description: Although the success of imatinib mesylate therapy represents an exciting advance in targeted cancer therapy, it has still to be determined whether responses to this p210 inhibitor in chronic myeloid leukemia (CML) patients will be durable. In fact most of clinical studies agree on the evidence of a persistent molecular disease in the majority of treated patients and altough the absolute level of bcr-abl transcript may vary over the treatment, yet a molecular complete response is of rare observation. In addition, discontinuation of imatinib exerts always in rapid loss of response. In accordance to this the persistence of malignant progenitors in patients in complete cytogenetic response (CCR) after short term imatinib treatment, has been recently demonstrated. In particular, Bathia et al. showed in 12/15 patients studied after a median time of 10 months of imatinib treatment a median of 11% of residual CML CD34+ progenitors in the bone marrow (by FISH Dual Fusion bcr/abl analysis)while only 3/15 patients had no detectable residual CD34+ cells. Less is known about residual Ph+/CD34+ cells surviving after a prolonged therapy with this targeting drug. Thus, we evaluated the amount of bone marrow residual CD34+ cells in 17 CML patients in stable CCR after a long lasting treatment with imatinib. At the time of evaluation, the patients were on conventional dose (400mg) Imatinib for a median time of 48 months (range 36–58 months) having achieved a CCR status (conventionally defined as the complete absence of t(9;22) on caryotypic analysis) within 3 to 6 months of treatment. However all of them still showed molecular disease as detected by nested RT-PCR. Bone marrow CD34+ cell-enriched populations were selected from mononuclear cells using immunomagnetic column separation and were evaluated after cytospin by FISH using a bcr-abl Dual Color Extra Signal Probe(LSI bcr-abl ES, Vysis), that is able to detect bcr-abl fusion in interphase nuclei with a false positive signal rate close to 0. A minimum of 100 CD34+ nuclei per each sample were evaluated. Interestingly, in 8/17 patients no Ph+/CD34+ cells were detected, while in the remaining 9/17 patients a median of 2% (range 0.5–11%) of bcr-abl positive progenitors were still observed. In this small selected serie of patients prolonged treatment with imatinib appears to be correlated with a lower, yet detectable, amount of residual bone marrow Ph+/CD34+ cells when compared to previously published data. This result could be partly explained with the different specificity and sensitivity of the probe used (bcr/abl ES

Description: We have shown that vaccinations with a p210-derived peptide vaccine (CMLVAX100) induced a strong peptide-specific CD4+T cell proliferation in the majority of vaccinated chronic myeloid leukemia (CML) patients. CD4+ T cell response was strictly mediated by the longest peptide included in the vaccine (b3a2-25) and correlated with disease response as about 65% of vaccinated patients showed reduction of minimal residual disease still persisting during imatinib treatment. The role of b3a2-25-peptide specific CD4+ T cells as potential mediator of antitumor response has not yet been fully elucidated. The majority of vaccine-induced T cells resulted to be CD4+/CD25+/Foxp3+, but despite this phenotype they showed no regulatory/inhibitory activity on naïve T cells. A smaller proportion resulted instead to be perforin+, thus potentially cytotoxic. To evaluate if b3a2-25-peptide specific CD4+T cells could exert a direct cytotoxic effect, we used CML-derived JURL-MK2 cell line expressing b3a2-p210 as target. Effector cells were b3a2-25-specific CD4+ T cells freshly isolated from 3 vaccinated patients and further in vitro expanded in the presence of IL-2 and b3a2-25 peptide. After in vitro expansion, peptide-specific CD4+/CD25+/Foxp3+ population represented about 60% of total CD4+ isolated cells, while peptide-specific CD4+/perforin+ cells counted for about 9%. Cellular cytotoxicity measurement was then carried out by flow cytometry using a fluorescent dye to label target cells and a fluorescent-DNA dye to determine the dead cells. Briefly, 1×104 JURL target cells labelled with DIOC18 green fluorescent dye were mixed with b3a2-25-specific CD4+ T (effector cells) at various E:T ratio (5:1, 10:1, 20:1, 35:1) and incubated 4 hours at 37°C. After co-incubation, Propidium Iodide (PI) red fluorescent was applied and the samples were run on flow cytometer for the determination of DIOC+/PI+ dead cells. Spontaneous cell death was determined by incubation at 37°C of target cells alone and maximum cell death was determined by incubation of target cells with 2% paraphormaldeide. Control experiments included different effector cells: freshly isolated CD4+ T cells from the same 3 vaccinated patients not further in vitro expanded (in this experimental condition the percentage of b3a2-25-specific CD4+/CD25+/Foxp3+ is about 10% of total CD4+ cells while b3a2-specific CD4+/perforin+ is about 2%); CD4+ T cells in vitro stimulated with IL-2 (without b3a2-25 peptide) from healthy subjects or from not previously vaccinated CML patients. Our results showed a specific killing of JURL-MK2 cells only in the presence of expanded peptide-specific CD4+ T cells from all 3 vaccinated patients with a linear increase of DIOC+/PI+ target cells from 5.3% (E:T 5:1) to 33% (E:T 35:1). No cytotoxicity was observed when CD4+ cells were expanded from healthy donors of from not vaccinated patients ruling out the possibility of killing mediated by a “non specific” activation of CD4+ cells due to IL-2 exposure. On the contrary, specific cytotoxicity appeared to correlate to the increased percentage of peptidespecific CD4+ cells obtained after in vitro re-stimulation with b3a2-25 peptide, as only background killing was observed when freshly isolated CD4+ T cells from all 3 vaccinated patients were cultured with JURL-MK2 cells. In conclusion, CMLVAX100 induced b3a2- 25-peptide specific CD4+ T cells appear to exert direct cytotoxity toward b3a2-CML JURL-MK2 cells. To our knowledge this is the first time that CML-peptide specific CD4+/cytotoxic T cells are induced in vivo and they could mediate the minimal disease reduction observed after CMLVAX100 vaccinations in CML patients. Experiments focused on determining which subtype, CD4+/CD25/Foxp3 or CD4+/perforin+, is the main effector of cytotoxicity as well as experiments clarifying if CD4+ cytotoxicity is mediated by HLA-DR molecules presentation of b3a2-p210 derived peptides are ongoing.

Description: Background: The association of Melphalan, Prednisone and Lenalidomide (MPR) has shown significant anti-myeloma activity in newly diagnosed Multiple Myeloma (MM) patients. In this phase I/II study, the more frequent adverse events were neutropenia and thrombocytopenia. Non-hematologic toxicities were unusual. Methods: We analyzed the kinetics and risk factors for neutropenia and thrombocytopenia in 21 patients (median age 69 years) who received nine four-week cycles of MPR at the maximum tolerated dose (melphalan 0.18 mg/Kg d 1–4, lenalidomide 10 mg d 1–21, prednisone 2 mg/Kg d 1–4, followed by maintenance period with lenalidomide 10 mg/day for 21 days every 4 weeks). We also up-dated efficacy end-point. At the occurrence of grade-3 neutropenia, G-CSF was administered for 5–7 days. The occurrence of grade-4 neutropenia despite G-CSF administration or any other grade-4 hematological toxicities required withholding of treatment and subsequent dose reduction at the start of the following cycle. A new cycle was allowed if the neutrophil count was 〉1×109/L and platelet count 〉50×109/L. A delay of 2 weeks was allowed, a delay beyond 2 weeks required dose reduction and a delay beyond 4 weeks required therapy discontinuation. Results: Grade-3 neutropenia occurred in 38.1% of patients, grade-4 neutropenia in 14.2% of patients, but febrile neutropenia was 9.5%. G-CSF was administered in 42.3% of patients. The mean neutrophil count at the start of each MPR cycle was 2.69 × 109/L (SD 1.4). The mean neutrophil count at nadir (day 15–21) of each cycle was 1.43 × 109/L (SD 1.0). The incidence and depth of neutropenia did not increase with the number of cycles. The mean neutrophil count during maintenance was 2.11 × 109/L (SD 1.0). Grade-3 thrombocytopenia occurred in 14.2% of patients and grade-4 thrombocytopenia in 9.5%; one patient required platelet transfusion. The mean platelet count at the start of each MPR cycle was 174 × 109/L (SD 63.9). The mean platelet count at nadir (day 15–21) of each cycle was 121 × 109/L (SD 56.3). Thrombocytopenia was more pronounced after 9 cycles of treatment. The mean platelet count after 9 cycles was 109 × 109/L (SD 53). The mean platelet count at the end of 6 months of lenalidomide maintenance therapy was 158 × 109/L (SD 79.2). One patient required lenalidomide dose reduction for severe neutropenia. Three patients discontinuated therapy for severe thrombocytopenia and neutropenia. Grade 3–4 hematologic toxicity was more frequent in patients with low baseline neutrophil count and in those with Bence-Jones myeloma. Neutropenic fever (9.5%), cutaneous reaction (9.5%), thromboembolism (4.8%) were the most frequent grade 3–4 non-hematologic adverse events. After a median follow-up of 29.5 months, the median time-to-progression was 28.5 months, the median progression-free survival was 28.5 months and the 2-years overall survival was 90.5%. No death was reported in the first 18 months of treatment. Conclusions: MPR is a promising first line regimen for elderly MM patients. Hematologic adverse events were frequent but manageable with the use of G-CSF.

Description: In the past five years, the body of data concerning imatinib mesylate had certainly defined the role of this drug as very effective first line debulking therapy for CML patients. However, both the persistence of molecular disease in most of patients together with the evidence that discontinuation of imatinib inevitably exerts on a rapid loss of response, suggest that with imatinib alone the cure of CML is unlikely. CMLVAX100 is a peptide-based vaccine that specifically targets p210-b3a2 in CML cells through the induction of a peptide-specific T cell response in b3a2-CML vaccinated patients. We recently published the preliminary results of a pilot study testing the immunological response and antitumor activity of vaccinations with CMLVAX100 in 10 patients showing persistent residual disease during treatment with imatinib. We here report the results on a larger cohort of patients and with a longer follow up. Up to date 21 patients were enrolled in this study. After a median time of 24 months (range 12–50) of imatinib treatment, patients started vaccinations with CMLVAX100 showing different degrees of persistent residual disease: 8/21 patients presented with molecular disease, 10/21 showed residual cytogenetic disease (range 2–45% of Ph+ metaphases), while 3/21 presented only an hematological response (100% of Ph+ metaphases). No improvement of their residual disease was documented for a median of 12 months (range 6–24) before starting vaccinations. Vaccine treatment plan included 6 vaccinations at 2 weeks interval (immunization) and for responder patients additional boosts of vaccine every 4–6 months. So far 18/21 patients completed the immunization and are evaluable for response; in addition 8/18 received 4 further boosts of vaccine. After immunization, CMLVAX100 induced a prompt immunological response in most of the patients as 17/18 patients showed peptide specific T cell response in vitro and 12/18 developed a positive delayed type hypersensitivity response in vivo. After 6 vaccinations 6/10 patients with persisting cytogenetic disease reached a complete cytogenetic response (CCR), with 3 of them achieving an undetectable level of bcr-abl transcript. In addition, 3/5 evaluable patients starting vaccinations with persistent molecular disease, further reduced their bcr-abl level, wth one reaching molecular negativity. None of the 3 patients vaccinated in hematological remission had cytogenetic response. Of the 8 patients who underwent 4 additional boosts of vaccine, one reached a complete molecular response, 5 maintained the response obtained after immunization, while 2 patients who previously achieved an undetectable level of bcr-abl transcript, lost the complete molecular response, while maintaining CCR, thus suggesting that a 6 months interval between boosts could be too long to maintain an efficient immune control on residual leukemic cells. In conclusion, we confirm that CMLVAX100 has a synergistic antitumor effect with imatinib in CML patients with persistent minimal residual disease. However, follow-up data recommend that closer boosts of vaccine are necessary in order to maintain an optimal level of response.

Description: Background. Lenalidomide (Revlimid® ) is a novel, orally active immunomodulatory drug, effective in multiple myeloma (MM) patients. In newly diagnosed patients the addition of Thalidomide to the standard oral melphalan and prednisone (MP) significantly increase response rate and event free-survival compared with MP. No data are available on the clinical use of Revlimid® in combination with MP. In this multicenter phase I/II trial, we evaluate the dosing, safety and efficacy of the combination Revlimid® , melphalan and prednisone (R-MP). Methods. Patients (pts) with newly diagnosed symptomatic MM older than 65 years were treated with 9 courses of Revlimid® (5–10 mg/day for 21days every 4–6 weeks) plus MP (melphalan 0.18–0.25 mg/kg and prednisone 2 mg/kg for 4 days every 4–6 weeks) followed by maintenance therapy with Revlimid® alone (10 mg/day for 21days every 4–6 weeks). Four different dose-levels were tested: 1.melphalan 0.18 mg/kg + Revlimid® 5 mg/day; 2.melphalan 0.25 mg/kg + Revlimid® 5 mg/day; 3.melphalan 0.18 mg/kg + Revlimid® 10 mg/day; 4.melphalan 0.25 mg/kg + Revlimid® 10 mg/day. Each cohort included 6 pts, with additional 15 pts enrolled at dose level 3 and 4. All pts received ciprofloxacin and aspirin (100 mg/day) as prophylaxis. Results. Between January and October 2005, 54 pts (median age 71) were enrolled in the study. No DLTs were observed in the first 2 dose-levels. In dose-level 3, one pt experienced DLT (grade 4 neutropenia lasting〉7 days). In dose-level 4, three pts showed DLTs (neutropenic fever, grade 3 cutaneous toxicity, pulmonary embolism, delay in the start of cycle 2) during the first cycle. The MTD was defined at dose-level 3 (melphalan 0.18 mg/kg+Revlimid® 10 mg/day). In the dose-levels 3 and 4, after a median of 7 cycles, all patients showed at least a minimal response and 85.4% of patients showed at least a partial response (PR); 41.5% of patients achieved at least a very good partial response (VGPR) and 17.1% of patients reached immunofixation negative complete remission (CR). In the dose-level 3, defined as MTD, 85.6% of patients showed at least a PR, including 52.3% of patients who achieved at least a VGPR and 23.8% who showed immunofixation negative CR. After a median follow up of 9.6 months, the progression free survival (PFS) was 87% at 16 months. FISH informations on chromosome 13q deletion were available in 42 patients (79%): no difference in response rate and PFS was observed between patients with or without 13q deletion. Toxicity was manageable, and occurred more frequently during early cycles. Major grade 3–4 adverse events consisted of hematological toxicities (neutropenia 66%, thrombocytopenia 34% and anemia 17%); major grade 3–4 non-hematological toxicities were cutaneous eruption (10%) and febrile neutropenia (8%). Three cases of tromboembolic events occurred: two of them after aspirin discontinuation, at cycle 7 and during maintenance. Conclusions. R-MP induced a high proportion of responses and appeared to overcome the poor prognosis of patients with chromosome 13q deletion. It was well tolerated, toxicities were predictable and manageable. An update of these data will be presented.

Description: Abstract 3578 Introduction: Chronic lymphocytic leukemia (CLL) patients bearing 13q14 deletion are known to experience a more favorable clinical course. Recent studies, focusing on patients with loss of 13q as the sole cytogenetic aberration at diagnosis (del13q-only cases), showed that the number of malignant cells carrying this genetic lesion correlates with a more aggressive clinical behavior. However, whether the size of the 13q deletion may also influence the clinical outcome remains to be elucidated. Patients and Methods: Probes for chromosome 13q (LSI-RB1, LSI-D13S319), 11q (LSI-ATM), 17p (LSI-p53) and chromosome 12 (CEP12) were utilized on nuclei collected at diagnosis from: i) a multi-institutional CLL cohort (342 del13q-only cases) and ii) a consecutive unselected single-institution cohort of 265 cases. RB1 deleted cases (delRB1) were defined as having at least 5% of deleted nuclei. Time to treatment (TTT) intervals, as well as Rai staging, IGHV mutational status, CD38 and ZAP70 expression, B2-microglobulin levels, all evaluated at diagnosis, were also available for all cases that entered the study. Genome wide DNA profile was performed in a pilot series of 90 CLL samples using Affymetrix GeneChip Human SNP6 arrays. Results: According to genome wide DNA analysis, delRB1 occurred in a proportion of del13q-only cases (36/90; 40%), always comprising the deleted region detected with the LSI-D13S319 probe (that covers the miR-15a/16-1 cluster and the DLEU2 gene) and characterized by a larger chromosome loss (median size 2.07 Mb vs. a median size of 0.86 Mb for the canonical del13S319). Maximally selected log-rank statistics identified the 70% of nuclei bearing del13S319 as the most appropriate cut-off value capable of separating del13q-only cases into two subgroups with different TTT distributions. Consistently, del13q-only cases with at least 70% of nuclei bearing del13S319 showed a significantly shorter TTT than del13q-only cases with less than 70% deleted nuclei (p=0.0001). Del13q-only cases were then divided in four subsets according to the percentage of nuclei bearing del13S319 with or without a concomitant delRB1: del13S319 70% + delRB1 (group 4), 39 cases. The median TTT of group 1 (not reached) was significantly longer than the median TTT of group 2 (92 months, p=0.012), group 3 (68 months, p