Mutant NPM1 is a Reliable Marker of Minimal Residual Leukemia in Patients with Acute Myeloid Leukemia

Mutant NPM1 is a Reliable Marker of Minimal Residual Leukemia in Patients with Acute Myeloid Leukemia

Abstracts hundred thirty six samples were obtained concomitantly from PB and BM (defined as obtained within a day of each other) from 63 patients. The ...

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Abstracts hundred thirty six samples were obtained concomitantly from PB and BM (defined as obtained within a day of each other) from 63 patients. The median time to CR was 30 days (range, 9-63). The median time to complete molecular response (CMR) was 130 days (range, 20-271). There was a strong correlation (Spearman correlation, r¼0.8, p <0.05) between PB and BM RQ-PCR on the 236 concomitant samples (fig 1); no significant difference were found between quantitative PCR values for BM and PB by paired Wilcoxon test analysis (p ¼ 0.30, paired Wilcoxon test). Conclusions: Among the available paired samples, there is a strong correlation between BM and PB RQ-PCR for PML-RARa fusion transcripts for patients treated with ATRA+ATO. PB RT-PCR is a reliable and practical method to monitor pts in CMR and for possible impending relapse. Figure 1 Spearman Correlation Between PB and BM Samples Obtained Concurrently (236 Samples) From 63 Patients Paired (Results Obtained From 202 RQ-PCR Samples Were 0 Both in PB and BM)

resistance against a panel of agents. Design: This assay was developed in 1536 well format and optimized against a panel of leukemia and lymphoma cell lines to determine optimal concentration of cells to be used. Twelve point dose response curves were performed in duplicate for all compounds. Alamar Blue was used as an indicator of cell viability. Results: Using this assay, we demonstrated in vitro resistance against drugs already clinically administered. Importantly, we also showed in vitro sensitivity to agents that had not been previously administered. The index patient was a 32-year-old woman with primary refractory AML who had received six different therapeutic regimens prior to testing, all of which demonstrated in vitro resistance using our assay. The blasts were sensitive, however, to 6-thioguanine with an inhibitory concentration (IC50) of 70 nanoM. Based on the in vitro data, she began a combination treatment regimen containing 6-thioguanine. Following a maintenance regimen, her circulating blast count decreased, and she had partial recovery of the neutrophil count, resulting in a dramatic decrease in the overall leukemia burden. This result was not seen with her previous therapies. After over six months of this therapy, her WBC began to rise and repeat testing indicated resistance to 6-thioguanine with IC50 > 10 microM, confirming the response seen in vivo. We have gone on to test samples from more than twenty-five patients with AML and have accurately predicted the in vivo clinical response (both sensitivity and resistance). In some cases, this provided the needed bridge to transplant. Conclusions: These data demonstrate that the technology described here to screen drug therapy for patients with relapsed/refractory AML is clinically useful and has a potential role in designing individualized treatment regimens for these patients.

**511 Mutant NPM1 is a Reliable Marker of Minimal Residual Leukemia in Patients with Acute Myeloid Leukemia

510 Clinical Implementation of a Novel HighThroughput Screen of Primary Leukemia Cells to Personalize Therapy for Relapsed/Refractory Acute Myeloid Leukemia (AML) David Shum, Mark L. Heaney, Renier J. Brentjens, Peter G. Maslak, Joseph G. Jurcic, Hakim Djaballah, Mark G. Frattini Leukemia Service, Experimental Therapeutics Center, Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, NY

Context: For patients with relapsed/refractory AML, therapeutic success is unpredictable with current chemotherapeutic regimens. Moreover, multiple courses of therapy have resulted in co-morbid conditions which can preclude the patient from receiving a bone marrow transplant. Objective: In order to identify a successful chemotherapy regimen for these patients, we have developed a high-throughput assay that utilizes primary (patientderived) leukemia cells and tested for chemo-sensitivity and

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Clinical Lymphoma, Myeloma & Leukemia September 2013

Preetesh Jain,1 Hagop Kantarjian,1 Stefan Faderl,1 Keyur Patel,2 Guillermo Garcia-Manero,1 Ohad Benjamini,1 Gautam Borthakur,1 Naveen Pemmaraju,1 Tapan Kadia,1 Naval Daver,1 Aziz Nazha,1 Raja Luthra,2 Sherry Pierce,1 Jorge Cortes,1 Farhad Ravandi1 1

Department of Leukemia, and 2Hematopathology, University of

Texas MD Anderson Cancer Center, Houston, Texas, USA

Context: NPM1 mutation is a reliable and stable marker for predicting higher CR rate, better outcomes in AML. Objective: To analyse the reliability of mutated NPM1 as a marker for MRD detection in patients with AML. Design and setting: A retrospective analysis of remission and relapse samples from patients (n¼360) with newly diagnosed AML who were tested for NPM1 mutation status at our institution (see flow chart below). NPM1 mutations were determined from BM aspirate samples by a PCR-based method at baseline, remission, and relapse. Main outcomes: 262 patients (72%) had de novo AML, and 98 (27%) secondary AML. Cytogenetics was diploid in 137 (38%) patients. Overall, 60 (16.6%) patients including 46 of the 137 (33.5%) diploid patients

Abstracts had NPM1 mutation at baseline. Secondary leukemia was more common in the NPM1 wild type (30%) than in the NPM1 mutated (13%) category. Among the patients with diploid cytogenetics who were younger than 60 years (n¼60) OS, EFS and CR duration was significantly better in the NPM1 mutated subset (p¼0.007, 0.007 and 0.02 respectively), while in those 60 years (n¼77) there was no statistically significant difference in the outcomes for the NPM1 mutated and wild-type subsets. Among the 60 NPM1 mutated patients 54 (90%) including 41/ 46 (89%) diploid achieved complete response (CR). 39 patients (including 30 with diploid karyotype) had available NPM1 status at the time of CR and all (100%) were negative for NPM1 mutation. Among the patients with mutated NPM1 at baseline who have achieved a NPM1 negative status at CR, 10/39 overall (25%) and 7/ 30 diploid (23%) patients relapsed. NPM1 status was available for 6 patients overall including 4 with diploid karyotype at the time of relapse. Among them, 5/6 overall (83%) and 3/4 diploid (75%) patients had mutated NPM1, while 1/6 overall (16%) and 1/4 diploid (25%) patients remained NPM1 wild type. Among the 300 patients (including 91 with diploid karyotype) with wild type NPM1 at diagnosis, none acquired a mutated NPM1 clone, either at CR or at the time of relapse. Conclusions: These data suggest that mutated NPM1 is a reliable and stable marker for the detection of MRD at the time of CR. Figure 2 Retrospective Analysis of Remission and Relapse Samples From Patients (n=360) With Newly Diagnosed AML who Were Tested for NPM1 Mutation Status at MD Anderson Cancer Center

Hady Ghanem, Elias Jabbour, Xuelin Huang, Farhad Ravandi, Guillermo Garcia-Manero, Stephan Faderl, Sherry Pierce, Sangbum Choi, Jorge Cortes, Hagop Kantarjian Leukemia Department, MD Anderson Cancer Center, Houston, Texas

Background: Successful therapy with HMAs in MDS is resulting in a larger proportion of pts developing AML following resistance to hypomethylating therapy. Response to therapy and outcomes of these patients (pts) with AML is unknown. Methods: Pts with a diagnosis of AML following failure of HMA for MDS treatment were reviewed. Response to therapy and outcomes were evaluated. Results: A total of 63 pts with AML following MDS and failure of HMA were reviewed. Their median age was 63 years (range, 38 to 90). Abnormal karyotypes were observed in 47 pts (75%), including adverse karyotypes consisting of chromosome 5 or 7 abnormalities in 28 (44) pts and complex karyotype in 26 (42%) pts. After progression to AML, all 63 pts (100%) received at least 1 salvage regimen, 37 (59%) received 2 or more salvage regimens and 15 pts (24%) received 3 more salvage regimens. Of the 31 pts (49%) who received high-dose cytarabine (HDAC)-based regimen at first salvage, 2 (6%) achieved complete remission (CR) and 4 (13%) CR without platelet recovery (CRp) (ORR:19%). Of the 32 pts (51%) who received other treatments including investigational agents as first salvage, 4 (12%) achieved CR and 4 (12%) achieved CR (ORR:24%). Of the 8 pts who received HDAC at 2nd relapse, one achieved CRp (ORR:12%). Of the 27 pts who received other agents at 2nd relapse, 3 (11%) achieved CR and 4 (15%) achieved CRp (ORR:26%). Median duration of response after 1st and 2nd salvage was 20 weeks. With a median follow up of 42 months after diagnosis of AML, the median overall survival (OS) was 21 weeks (25 weeks for HDAC, 20 weeks for other therapies, p¼0.76). The 1 year survival rate was 19%. The 8 week overall mortality was 23% with intensive chemotherapy and 21% with other therapies (p¼0.93). Male gender, platelet count <50x109 and age>65 were independent factors for poor survival on multivariate analysis, with a trend for worse survival for patients receiving HDAC treatments. Conclusion: AML following MDS and failure of hypomethylating agents is becoming an increasingly frequent entity. Outcomes of such pts are extremely poor with a median OS of 21 weeks, and are not improved with HDAC chemotherapy. Exploring the molecular and genomic profiles of this entity and developing novel targeted therapies directed towards it are urgently needed.

*514 Targeted Alpha-particle Nano-generator Actinium-225 (225Ac)-lintuzumab (anti-CD33) in Acute Myeloid Leukemia (AML)

512 Acute Myeloid Leukemia (AML) Following Myelodysplastic Syndrome (MDS) and Failure of Therapy with Hypomethylating Agents (HMA): An Emerging Entity With a Poor Prognosis

J.G. Jurcic, T.L. Rosenblat, M.R. McDevitt, N. Pandit-Taskar, J.A. Carrasquillo, S.M. Chanel, K. Zikaras, M.G. Frattini, P.M. Maslak, D. Cicic, S.M. Larson, D.A. Scheinberg Memorial Sloan-Kettering Cancer Center, New York, NY; 2Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, NY; Actinium Pharmaceuticals, Inc., Newark, NJ

Clinical Lymphoma, Myeloma & Leukemia September 2013

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