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The aim of this retrospective, multicenter study was to compare high- versus standard-dose lenograstim after chemotherapy in collecting target dose of CD34+ peripheral blood progenitor cells (PBPCs) in adult candidates for autologous transplant.A total of 166 consecutive patients (28 acute leukemias [ALs], 77 lymphomas, 61 multiple myeloma [MM]) underwent 182 mobilization procedures. Only the first were analyzed. The CD34+ cell target was at least 2×10(6) , 4×10(6) , and 8×10(6) /kg and lenograstim started on days +19, +1, and +5 from the end of chemotherapy for AL, lymphomas, and MM, respectively. Eighty-seven and 79 patients, respectively, received 5 and 10µg/kg/day lenograstim subcutaneously (sc). An analysis to evaluate factors predicting satisfactory procedures and outcome of transplants performed with first-mobilization-procedure PBPCs was conducted. Most patients received 6mg of pegfilgrastim or 5µg/kg/day lenograstim sc after transplant.In multivariate analysis, high-dose lenograstim (p=0.053) in MM and male sex (p=0.028) were positive predictive factors for reaching cell target. Fludarabine negatively influenced stimulation length (p=0.002). Apheresis, CD34+ cells mobilized and collected, blood volume processed, side effects, transplants performed, and engraftment time were similar between lenograstim cohorts. Pegfilgrastim versus lenograstim delayed platelet (PLT) recovery times (13 days vs. 11 days, p=0.036).High-dose lenograstim more efficiently mobilized MM patients requiring the highest PBPC target but did not influence transplants performed and engraftment time. Male patients mobilized more efficiently. Fludarabine negatively influenced stimulation length. Finally, pegfilgrastim seems to delay PLT recovery.

Abstrac Objective: To evaluate the clinical characteristics and outcome of NK/T-cell lymphoma ‘nasal type’ developed in Italian patients. Patients: Between 1997 and 2004, 26 new cases of NK/T-cell lymphoma ‘nasal type’ were diagnosed in 10 Italian Hematology institutions. Results: All patients were Caucasian, male/female ratio was 19/7, with a median age of 50 years (range 20–80). In 23 cases presentation at the onset was in the nasal cavity or adjacent structures, in two cases the lymphoma onset with skin lesions was followed successively by rhynopharyngeal dissemination, while the remaining case had bone marrow and lymph node involvement followed by oro-pharyngeal involvement. Regarding the stage of disease: 12 patients were in stage I; six in stage II; eight in stage IV. Diagnosis was based on the finding of a NK/T-cell phenotype at the histological and immunophenotypic examination of oropharyngeal or cutaneous lesions. All patients but one were treated with chemotherapy, alone in nine cases or associated to radiotherapy in 14 cases; two patients had chemotherapy, radiotherapy and surgery, while one patient underwent only surgery. Chemotherapy was anthracycline-based in 17 out of 25 cases. In those patients in whom radiotherapy was performed, radiation dosages ranged between 36 Gy and 47.5 Gy, with a median dosage of 40 Gy. Nine patients (34%) were responsive to the treatments: six patients obtained a complete remission and other three a partial remission. The remaining 17 patients resulted refractory or presented a limited response to therapy. The median disease-free survival was 14 months and the median overall survival time was 9 months. Conclusion: The results of this retrospective survey confirmed that NK/T-cell lymphoma ‘nasal type’ is a very rare lymphoma in the Italian population, and it is characterized by a very bad prognosis. Due to the rarity of this disease, a standardized therapeutic approach is lacking. More data are needed to know the epidemiology of this kind of lymphoma in Europe.

Eleven patients with advanced APL were treated with ATO (0.15 mg/Kg daily). Eight (73%) achieved molecular CR, but 5 relapsed, 1 died in molecular CR, 1 was lost to follow-up and 1 is still alive in CR after allogeneic transplantation. We suggest that ATO may be effective also in advanced APL, but given the short CR, it seems indicated only in patients eligible for transplant procedures.

Extramedullary relapse occurs infrequently in acute promyelocytic leukaemia (APL) but has been increasingly reported after the advent of all-trans retinoic acid (ATRA) treatment, probably as a consequence of improved patient survival. We describe our single centre experience of six APL patients who had disease localization in the central nervous system (CNS). In three patients, clinical symptoms (headache and/or nausea) that presented during follow-up led to the performance of a lumbar puncture and detection of overt CNS infiltration. Two of these patients had simultaneous haematological relapse and one was in molecular remission when CNS leukaemia was documented. One patient with no local symptoms showed CNS infiltration at the time of molecular relapse. Following the introduction of routine lumbar puncture, carried out after front-line induction in all newly diagnosed patients with white blood cell count (WBC) greater than 10 x 109/l, two additional patients in molecular remission with no local symptoms were found to have initial APL localization in the CNS. Presenting features included in 6/6 patients an elevated WBC count (10 x 109/l) and a predominance of the PML/RAR bcr3 type (5/6 patients) and of microgranular morphology (5/6 patients). Our findings highlight the importance of carrying out lumbar puncture in APL patients presenting with high-risk features.

Summary Objective To evaluate in a multicenter retrospective study, the clinical and laboratory characteristics and the outcome of patients with acute myeloid leukemia (sAML) previously diagnosed with breast cancer (BC) among an adult acute leukemia population. Patients and methods Between June 1992 and July 1996, 3934 new cases of adults with acute leukemia were recorded in GIMEMA Archive of Adult Acute Leukemia (2964 AML, 901 ALL, 69 acute leukemia expressing both myeloid and lymphoid surface markers). Results Two hundred patients (5.1%) presented with a history of previous malignancy (21 of them were affected by ALL and 179 by AML). Among sAML, 37 patients (29%) had a previous breast cancer. They consisted of 36 females and 1 male, median age 56 years, range 34–87. The median latency between the 2 malignancies was 54 months (range 5–379). Twenty-seven patients received chemo- and/or radiotherapy for breast cancer (7 only chemotherapy, 6 only radiotherapy, and 14 combined treatment). All patients were surgically treated but in 10 patients surgical debridement was the sole therapy for breast cancer. The drugs most frequently employed were alkylating agents (18 patients), topoisomerase II inhibitors (9 patients), antimetabolites (20 patients) (CMF, CEF and MMM combinations). At onset of sAML the median WBC count was 7.7 × 109/l (0.8–153) and the median platelet count was 33.5 × 109/l (3–305). Considering morphological features. FAB subtypes were 4 M0, 5 MI, 11 M2, 5 M3, 8 M4, 3 M5, and 1 M6. Cytogenetic study was performed on 28 patients and 12 of them presented abnormalities. It is noteworthy that chromosome 5 or 7 abnormalities (typically observed in those patients treated with alkylating agents) were present only in three cases. Thirty-four patients received chemotherapy for sAML, and twenty-five of them achieved a CR (74%), with a median duration of twenty-eight weeks (5–280 +). The overall survival was 8 months (1–80 +). Discussion The high number of sAML we observed in patients with a previous breast cancer, may be due to the fact that this malignancy is the most frequent neoplasm in women and by the high probability of cure with a consequent long disease-free survival. Our results suggest that the risk of sAML after recovery from breast cancer is increasing due to the rise in the number of patients cured from breast cancer, and in the future could be a relevant problem for haematologists.

Thirty-one patients with either advanced AML (18) or blastic CML (13) were treated with an intensive timed sequential combination of VP-16 (100 mg/m2/day i.v., days 1-3 and 8-10), intermediate-dose Ara-C (500 mg/m2 i.v. over 1 h q 12 h, days 1-3 and 8-10) and carboplatin (150 mg/m2/day i.v. continuous infusion, days 1-3 and 8-10). CR rates were 9/18 (50%) for patients with AML and 9/13 (69%) for those with blastic CML, for an overall CR rate of 58%. Among patients with AML, CR rates for specific subgroups were: primary resistant disease 2/6; resistant relapse 1/5; second relapse 6/7. Ten patients were refractory to VAC and three (10%) died of complications during marrow hypoplasia. Median overall survival was 7 months, and median DFS of the 18 responders 4 months. The major toxicity was myelosuppression and infection. The VAC regimen has significant activity and acceptable toxicity in myelogenous leukemias. The very high response rate observed in blastic CML warrants further testing of carboplatin-based regimens in this poor-risk form of leukemia.

Hybrid fusion genes are specific tumor markers of several leukemic subtypes. The use of reverse transcription-polymerase chain reaction (RT-PCR) to amplify chimeric cDNAs allows sensitive detection of the neoplastic clone for diagnostic and monitoring studies in these leukemias. Nonetheless, the clinical relevance of minimal residual disease (MRD) evaluation by PCR remains controversial. In this study, 9 patients (pts) with acute promyelocytic leukemia (APL) in long-term remission for 4 to 12 years were analyzed for the presence of MRD by RT-PCR amplification of the specific PML/RAR-alpha fusion gene. Seven pts had been treated with conventional chemotherapy (CHT) alone, 1 had undergone allogeneic bone marrow transplantation (BMT), and 1 autologous BMT as consolidation therapy after CHT. In 8 cases, the presence of the t(15;17) rearrangement could be documented in diagnostic BM specimens by cytogenetic and/or molecular analysis. A two-rounds "nested" RT-PCR assay with sensitivity levels of 1 in 10(5) was used to analyze BM samples collected at 32 to 141 months from the achievement of complete remission (CR). In no cases were residual PML/RAR-alpha transcripts detectable in these remission controls. All patients are in unmaintained CR at 48 to 154 months from CR and at 6 to 17 months from PCR evaluation. These results suggest that long-term survival of APL is associated with eradication of cells carrying the specific PML/RAR-alpha rearrangement, indicating that PCR negativity should be considered the therapeutic goal in these patients. Our findings further strengthen the clinical relevance of PCR monitoring studies in APL, as opposite to other leukemic subtypes (chronic myeloid leukemia and acute myeloid leukemia-M2) in which the prognostic significance of PCR evaluation is unclear.

Nine patients with recurrent acute promyelocytic leukemia have been treated between July, 1984 and November, 1987 with a combination therapeutic regimen consisting of amsacrine, cytosine arabinoside and thioguanine (AAT). Complete remission was achieved in 5/9 patients, one person died in aplasia of hepatic failure, and the remaining 3 died from heart failure with resistant disease. The 5 patients who achieved CR were successively treated with allogeneic (n = 2) or autologous bone marrow transplantation (n = 3). As of December, 1988 there were only 2 patients still alive and in CR, both underwent autologous bone marrow transplantation. The duration of the second complete remission in these two patients is 48+ and 29+ months, respectively. Moreover the overall survival duration for these two patients is 88+ and 41+ months, respectively. These data confirm that the AAT regimen is useful in treating recurrent acute promyelocytic leukemia, a disease otherwise characterized by a catastrophic clinical course during the recurrent phase.

Serum interleukin-2 (IL-2), soluble IL-2 receptors (sIL-2R) and tumor necrosis factor-alfa (TNF-alpha) levels were determined in 66 previously untreated consecutive patients with acute myeloid leukemia (AML) and in 22 normal volunteers. The following mean (+/- SE) values were observed in patients and controls, respectively: 35 +/- 14.7 (range 0.5-500) and 0.7 +/- 0.02 (0.5-0.8 U/ml for IL-2 (p = 0.001); 1622 +/- 289 (110-10,600) and 422 +/- 30 (207-666) U/ml for sIL-2R (p = 0.0001); 1247 +/- 196 (218-4672) and 152 +/- 11 (75-308) pg/ml for TNF-alpha (p = 0.0001). With respect to the FAB classification system, we found a significantly different distribution of serum IL-2 mean values in distinct subcategories, i.e. 3.4 +/- 1.9 U/ml in M1-M2-M3 and 42.4 +/- 20.4 U/ml in M4-M5 subgroups, respectively (p = 0.01), whereas sIL-2R and TNF-alpha levels were 1144 +/- 322 U/ml and 1120 +/- 317 pg/ml in M1-M2-M3 patients and 1945 +/- 317 U/ml and 1270 +/- 259 pg/ml in the M4-M5 group. A significantly positive correlation between TNF-alpha and sIL-2R (r = 0.53; p = 0.002) was also detected in the M4-M5 group. Sixty-three out of 66 patients received an intensive chemotherapy program. Univariate analysis showed that age and sIL-2R greater than 2000 U/ml significantly affected both complete remission rate and overall survival, whereas by multivariate analysis, age was the only independent variable significantly influencing survival. These data confirm recent in vitro evidence suggesting the role of IL-2, sIL-2R, and TNF-alpha in the control of normal hematopoiesis and leukemogenesis. Since the availability of recombinant cytokines for clinical use in AML, it is crucial to understand their spectrum of interaction in order to select the appropriate combination for in vivo administration.

5-Aza-2'-deoxycytidine (Decitabine) is a new cytosine analog with potent antileukemic activity and able to induce in vitro gene activation and cellular differentiation by a mechanism probably involving DNA hypomethylation. The aim of this pilot study was to evaluate the efficacy and the toxicity of Decitabine, used as single induction agent, in the treatment of poor prognosis acute myeloid leukemia (AML) patients, and to explore its mechanism of action. A total of 12 patients were treated with Decitabine at 90-120 mg/m2 as a four hour intravenous infusion, three times daily for three consecutive days every four to six weeks. A minimum of two courses were required for response evaluation and to consider a patient as therapeutic failure. A total of 10/12 patients were fully evaluable for response; three patients achieved a complete remission (CR) and one a partial remission (PR). Extra-hematological toxicity was generally mild. As for the mechanism of action, both a differentiation induction effect and a cytotoxic mechanism have been observed. In particular, CRs and PRs were probably obtained through the induction of leukemia cell differentiation as shown by the kinetic of remission and immunotyping studies. The preliminary results of this ongoing study suggest that Decitabine may have a prominent role in the treatment of those AML patients with poor general conditions and/or advanced age.

Preliminary independent reports of the Italian GIMEMA and the Spanish PETHEMA trials for newly diagnosed acute promyelocytic leukemia (APL) indicated a similarly high antileukemic efficacy in terms of complete remission and disease-free survival rates. To better investigate these studies and the prognostic factors influencing relapse risk, this study analyzed the updated results of 217 patients with PML/RAR alpha-positive APL enrolled in GIMEMA (n = 108) and PETHEMA (n = 109). All patients received identical induction (AIDA schedule) and maintenance. For consolidation, GIMEMA patients received 3 courses including idarubicin/cytarabine, mitoxantrone/etoposide, and idarubicin/cytarabine/thioguanine, whereas PETHEMA patients received the same drugs and dose schedule of idarubicin and mitoxantrone with the omission of nonintercalating agents. Depending on whether molecular relapses were classified as censored or uncensored events, the 3-year Kaplan-Meier estimates of relapse-free survival (RFS) for the combined series were 90 +/- 2% and 86 +/- 2%, respectively. Minor differences observed between the 2 patient cohorts were negligible. Multivariate regression analysis of RFS showed that initial leukocyte (WBC) and platelet counts were the only variables with independent prognostic value. The resulting predictive model for RFS demonstrated its capability of segregating patients into low-risk (WBC count/= 10 x 10(9)/L, platelet count40 x 10(9)/L), intermediate-risk (WBC count/= 10 x 10(9)/L, platelets/= 40 x 10(9)/L), and high-risk (WBC count10 x 10(9)/L) groups, with distinctive RFS curves (P.0001). The conclusions are that omission of nonanthracycline drugs from the AIDA regimen is not associated with reduced antileukemic efficacy and a simple predictive model may be used for risk-adapted therapy in this disease. (Blood. 2000;96:1247-1253)

Forty-seven patients with primary refractory, relapsed, and previously untreated, poor risk AML were entered into a phase II study of intermediate dose ARA-C (IDAC) (1 g/m2 i.v. over 6 hr, daily for 6 days) with sequential mitoxantrone (MITOX) (6 mg/m2 i.v. bolus 3 hr after the end of each ARA-C infusion). Overall, complete remission was induced in 31 patients (66%), and 1 additional patient entered a partial remission. Seven patients (15%) died of infection during marrow hypoplasia. Response to IDAC + MITOX was influenced by sensitivity to previous therapy: patients with primary refractory and early relapse AML responded less well to the regimen (CR rate 28% and 33%, respectively), as compared to those with previously untreated (CR rate 64%) or late relapse disease (CR rate 85%). Sixteen patients continue in CR at 1-12+ months. Except for the expected severe myelosuppression, the regimen was well tolerated with minimal extramedullary toxicity. The data indicate that the sequential combination of IDAC and MITOX is an effective and tolerable regimen for AML. Consideration should be given to applying this program at earlier stages of AML therapy.

BACKGROUND: The incidence of chronic myeloid leukemia (CML) increases with age, but it is unclear how the characteristics of the disease vary with age. In children, where CML is very rare, it presents with more aggressive features, including huge splenomegaly, higher cell count and higher blast cell percentage. PATIENTS AND METHODS: To investigate if after childhood the disease maintains or loses these characteristics of aggressiveness, we analyzed 2784 adult patients, at least 18 years old, registered by GIMEMA CML WP over a 40-year period. RESULTS: Young adults (YAs: 18-29 years old) significantly differed from adults (30-59 years old) and elderly patients (at least 60 years old) particularly for the frequency of splenomegaly (71%, 63% and 55%, P < 0.001), and the greater spleen size (median value: 4.5, 3.0 and 1.0 cm, P < 0.001). According to the EUTOS score, that is age-independent, high-risk patients were more frequent among YAs, than among adult and elderly patients (18%, 9% and 6%, P < 0.001). In tyrosine kinase inhibitors-treated patients, the rates of complete cytogenetic and major molecular response were lower in YAs, and the probability of transformation was higher (16%, 5% and 7%, P = 0.011). CONCLUSIONS: The characteristics of CML or the host response to leukemia differ with age. The knowledge of these differences and of their causes may help to refine the treatment and to improve the outcome. CLINICAL TRIAL NUMBERS: NCT00510926, NCT00514488, NCT00769327, NCT00481052. © The Author 2014. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

The High Mobility Group A (HMGA) are nuclear proteins that participate in the organization of nucleoprotein complexes involved in chromatin structure, replication and gene transcription. HMGA overexpression is a feature of human cancer and plays a causal role in cell transformation. Since non-coding RNAs and pseudogenes are now recognized to be important in physiology and disease, we investigated HMGA1 pseudogenes in cancer settings using bioinformatics analysis. Here we report the identification and characterization of two HMGA1 non-coding pseudogenes, HMGA1P6 and HMGA1P7. We show that their overexpression increases the levels of HMGA1 and other cancer-related proteins by inhibiting the suppression of their synthesis mediated by microRNAs. Consistently, embryonic fibroblasts from HMGA1P7-overexpressing transgenic mice displayed a higher growth rate and reduced susceptibility to senescence. Moreover, HMGA1P6 and HMGA1P7 were overexpressed in human anaplastic thyroid carcinomas, which are highly aggressive, but not in differentiated papillary carcinomas, which are less aggressive. Lastly, the expression of the HMGA1 pseudogenes was significantly correlated with HMGA1 protein levels thereby implicating HMGA1P overexpression in cancer progression. In conclusion, HMGA1P6 and HMGA1P7 are potential proto-oncogenic competitive endogenous RNAs.

We investigated whether body mass index (BMI) correlates with distinct outcomes in newly diagnosed acute promyelocytic leukemia (APL). The study population included 144 patients with newly diagnosed and genetically confirmed APL consecutively treated at a single institution. All patients received All-trans retinoic acid and idarubicin according to the GIMEMA protocols AIDA-0493 and AIDA-2000. Outcome estimates according to the BMI were carried out together with multivariable analysis for the risk of relapse and differentiation syndrome. Fifty-four (37.5%) were under/normal weight (BMI < 25), whereas 90 (62.5%) patients were overweight/obese (BMI ≥ 25). An increased BMI was associated with older age (P < .0001) and male sex (P = .02). BMI was the most powerful predictor of differentiation syndrome in multivariable analysis (odds ratio = 7.24; 95% CI, 1.50-34; P = .014). After a median follow-up of 6 years, the estimated cumulative incidence of relapse at 5 years was 31.6% (95% CI, 22.7%-43.8%) in overweight/obese and 11.2% (95% CI, 5.3%-23.8%) in underweight/normal weight patients (P = .029). Multivariable analysis showed that BMI was an independent predictor of relapse (hazard ratio = 2.45, 95% CI, 1.00-5.99, in overweight/obese vs under/normal weight patients, P = .049). An increased BMI at diagnosis is associated with a higher risk of developing differentiation syndrome and disease relapse in APL patients treated with AIDA protocols.

Purpose: Epigenetic changes play a role and cooperate with genetic alterations in the pathogenesis of myelodysplastic syndromes (MDS). We conducted a phase II multicenter study on the combination of the DNA-methyltransferase inhibitor 5-azacytidine (5-AZA) and the histone deacetylase inhibitor valproic acid (VPA) in patients with higher risk MDS. Experimental Design: We enrolled 62 patients with MDS (refractory anemia with excess blasts, 39 patients; refractory anemia with excess blasts in transformation, 19 patients; and chronic myelomanocytic leukemia (CMML), 4 patients) and an International Prognostic Scoring System (IPSS) rating of Intermediate-2 (42 patients) or high (20 patients). VPA was given to reach a plasma concentration of >50 μg/mL, then 5-AZA was added s.c. at 75 mg/m2 for 7 days in eight monthly cycles. Results: The median overall survival was 14.4 months. At a median follow-up of 12 months (range, 0.7-21.0), the disease progressed in 20 patients, with 21% cumulative incidence of progression. Of 26 patients who completed eight cycles, 30.7% obtained complete or partial remission, 15.4% had a major hematologic improvement, whereas 38.5% showed stable disease. Drug-related toxicity was mild. Favorable prognostic factors for survival were IPSS Intermediate-2 and plasma VPA of ≥50 μg/mL (log rank = 0.013 and 0.007, respectively). Analysis of polymorphisms important for the metabolism of the drugs used in the trial showed that carriers of the CYP2C19*2 variant of cytochrome P450 required higher VPA doses to achieve the target VPA plasma concentration of 50 μg/mL on day 1 of 5-AZA treatment (P = 0.0021). Conclusion: Our data show that the 5-AZA/VPA combination is active and safe in patients with MDS with a poor prognosis. Achievement of VPA therapeutic levels may indeed increase 5-AZA efficacy.

In a randomized, phase 3 study, superior complete/near-complete response (CR/nCR) rates and extended progression-free survival were demonstrated with bortezomib-thalidomide-dexamethasone (VTD) versus thalidomide-dexamethasone (TD) as induction therapy before, and consolidation after, double autologous stem cell transplantation for newly diagnosed myeloma patients (intention-to-treat analysis; VTD, n = 236; TD, n = 238). This per-protocol analysis (VTD, n = 160; TD, n = 161) specifically assessed the efficacy and safety of consolidation with VTD or TD. Before starting consolidation, CR/nCR rates were not significantly different in the VTD (63.1%) and TD arms (54.7%). After consolidation, CR (60.6% vs 46.6%) and CR/nCR (73.1% vs 60.9%) rates were significantly higher for VTD-treated versus TD-treated patients. VTD consolidation significantly increased CR and CR/nCR rates, but TD did not (McNemar test). With a median follow-up of 30.4 months from start of consolidation, 3-year progression-free survival was significantly longer for the VTD group (60% vs 48% for TD). Grade 2 or 3 peripheral neuropathy (8.1% vs 2.4%) was more frequent with VTD (grade 3, 0.6%) versus TD consolidation. The superior efficacy of VTD versus TD as induction was retained despite readministration as consolidation therapy after double autologous transplantation. VTD consolidation therapy significantly contributed to improved clinical outcomes observed for patients randomly assigned to the VTD arm of the study. The study is registered at www.clinicaltrials.gov as #NCT01134484.

All-trans-retinoic acid (ATRA) has greatly modified the prognosis of acute promyelocytic leukemia; however, the role of maintenance in patients in molecular complete remission after consolidation treatment is still debated. From July 1993 to May 2000, 807 genetically proven newly diagnosed acute promyelocytic leukemia patients received ATRA plus idarubicin as induction, followed by 3 intensive consolidation courses. Thereafter, patients reverse-transcribed polymerase chain reaction–negative for the PML-RARA fusion gene were randomized into 4 arms: oral 6-mercaptopurine and intramuscular methotrexate (arm 1); ATRA alone (arm 2); 3 months of arm1 alternating to 15 days of arm 2 (arm 3); and no further therapy (arm 4). Starting from February 1997, randomization was limited to ATRA-containing arms only (arms 2 and 3). Complete remission was achieved in 761 of 807 (94.3%) patients, and 681 completed the consolidation program. Of these, 664 (97.5%) were evaluated for the PML-RARA fusion gene, and 586 of 646 (90.7%) who tested reverse-transcribed polymerase chain reaction–negative were randomized to maintenance. The event-free survival estimate at 12 years was 68.9% (95% confidence interval, 66.4%-71.4%), and no differences in disease-free survival at 12 years were observed among the maintenance arms.

Although the majority of patients with acute promyelocytic leukemia (APL) are potentially cured by treatments combining all-trans retinoic acid (ATRA) and chemotherapy (CHT), a sizable proportion (around 30%) will relapse during follow-up. Retrospective molecular monitoring studies using reverse transcriptase-polymerase chain reaction (RT-PCR) for the specific PML/RARalpha fusion gene, have shown that a positive test usually precedes the occurrence of hematologic relapse. Prospective RT-PCR analyses were performed since 1993 at diagnosis and at preestablished time intervals during follow-up in bone marrow (BM) samples of 163 patients with PML/RARalpha+ APL enrolled in the multicenter Gruppo Italiano Malattie Ematologiche Maligne dell' Adulto (GIMEMA) trial AIDA (All-trans retinoic acid plus Idarubicin). Treatment consisted of ATRA and idarubicin for induction followed by three polychemotherapy courses as consolidation. The sensitivity level of the RT-PCR assay for PML/RARalpha, as assessed by serial dilution experiments, was 10(-4). All patients were in hematologic remission and tested PCR- at the end of consolidation. Of 21 who converted to PCR-positive thereafter, 20 underwent hematologic relapse at a median time of 3 months (range, 1 to 14) from the first PCR+ result. Seventeen of these 21 (81%) PCR+ conversions were recorded within the first 6 months postconsolidation. Of 142 who tested persistently PCR- in >/=2 tests after consolidation, 8 had hematologic relapse and 134 remained in complete remission (CR) after a median follow-up of 18 months (range, 6 to 38) postconsolidation. Using a time-dependent Cox model, the relative risk of hematologic relapse of patients who converted to PCR+ was 31.8 (confidence limits 95%, 12.9 to 78.3). Our results indicate that conversion to PCR positivity for PML/RARalpha during remission is highly predictive of subsequent hematologic relapse and highlight the prognostic value of stringent molecular monitoring during the early postconsolidation phase in APL. As a result of the present study, salvage treatment in patients enrolled in the GIMEMA trial AIDA is now anticipated at the time of molecular relapse, defined as the conversion to PCR positivity in two successive BM samplings during follow-up.