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Bosutinib is a second-generation tyrosine kinase inhibitor (2GTKI) approved at 400 mg once daily (QD) as first-line therapy in patients with chronic myeloid leukemia (CML) patients and at 500 mg QD in patients who are resistant to or intolerant of prior therapy. In clinical practice, bosutinib is often given to patients who have failed imatinib, nilotinib, and dasatinib (i.e., as fourth-line treatment), despite the limited data on its clinical benefit in this setting. We have retrospectively evaluated the results of bosutinib in a series of 62 CML patients who have failed to prior treatment with all three, imatinib, nilotinib, and dasatinib. Median time on TKI treatment before bosutinib start was 105 (9–163) months, and median duration on bosutinib was 9 months (1–30). Overall, probabilities to achieve complete cytogenetic response (CCyR) and major molecular response (MMR) were 25% and 24% respectively. After a median follow-up period of 14 months, the event-free survival and progression-free survival were 68 and 85%, respectively. Sixty-four percent of patients in CCyR at the time of bosutinib start were able to achieve MMR. In contrast, patients without CCyR, probabilities to obtain CCyR and MMR were 25% and 14%. Bosutinib was well tolerated in this heavily pretreated patients’ cohort. Pleural effusions and diarrhea were the most frequent grade II–IV side effects, leading to treatment discontinuation in 16% of patients. Bosutinib is an effective treatment option for patients who have failed previous 2GTKIs due to intolerance. However, efficacy seems to be related to the molecular response that the patient achieved prior to bosutinib.

The role of bosutinib as rescue treatment of Philadelphia chromosome-positive chronic myeloid leukemia (CML) patients after failing three previous tyrosine kinase inhibitors (TKIs) is currently unknown. We report here the largest series (to our knowledge) of patients treated with bosutinib in fourth-line, after retrospectively reviewing 30 patients in chronic phase, and pretreated with imatinib, nilotinib, and dasatinib. With a median follow up of 11.1 months, the probability to either maintain or improve their CCyR response was 56.6% (17/30) and 11 patients (36.7%) achieved or maintained their baseline MMR. In patients not having baseline CCyR, the probabilities of obtaining CCyR, MMR, and MR4.5 were 13, 11, and 14%, respectively. The probabilities of obtaining MMR and deep molecular response MR4.5 in patients with baseline CCyR were 40.0% (6/15) and 20.0% (3/15). At 20 months, progression-free survival was 73%. Grade 3-4 hematological toxicities were more frequent in resistant than intolerant patients (45.4 vs. 0.0%). Nonhematological toxicities were also more frequent in resistant patients, being diarrhea the most conspicuous one. Bosutinib seems to be an appropriate treatment option for patients resistant or intolerant to three prior TKI's.

Introduction: Multiple Myeloma (MM) is an incurable disease. In young patients, autologous bone marrow transplantation (ABMT) remains a cornerstone treatment after induction therapy. Induction therapy has varied during time, from alkylating polychemotherapy (VBAD,VCMP) or VAD chemotherapy (AVAD) to Velcade-Dexametasone based regimens (VD). We present results of follow-up of a large cohort of patients treated with ABMT. We described overall survival (OS; from transplant to death by any cause) and progression free survival (PFS; from transplant to death by any case or progressive disease defined by reappearance by inmunofixation, or duplication of monoclonal peak after ABMT) , and the impact of induction therapy regiments. Patients: 183 patients transplanted from 2002 to 2017. The median age of the patients was 59 years (33-72). Before 2008 all the patients were treated in alkylating based chemotherapy (42 patients). After 2008 patients were treated with VD based regimens (141patients). Only 12 patients received maintenance therapy based in PETHEMA trials 2005 and 2012. No one patient received a planed second transplant; only 32 patients received a second transplant after relapse as consolidation therapy. Results: Median follow-up of patients still alive is 3.65 years (0.15-14.77). Median OS of all patients was 9.12 years (95% confidence interval (CI): 6.28-NR); Median PFS was 3.02 years(95% CI: 2.46-3.76). At 13 years only 2% of patients remains progression free (CI: 0.00-17%). There were significant differences between patients treated before and after VD regimens. The median OS of patients treated with APVAD was significantly shorter compared to VD (6.22 years, CI[3.39-12] vs. NR, CI[6.28-NR], p=0.025) (HR=0.49, p=0.01). Conclusions: VD schemes of induction before ABMT have improved remarkably OS inpatients with Myeloma; nonetheless, plateau is not observed in EFS. Further analysis must address if EFS could represent a strong indicator of OS, mainly due to novel effective salvage therapies after relapse/refractoriness could be a confounding factor. Figure. Figure. Disclosures No relevant conflicts of interest to declare.

The role of bosutinib as rescue treatment of Philadelphia chromosome-positive chronic myeloid leukemia (CML) patients after failing three previous tyrosine kinase inhibitors (TKIs) is currently unknown. We report here the largest series (to our knowledge) of patients treated with bosutinib in fourth-line, after retrospectively reviewing 30 patients in chronic phase, and pretreated with imatinib, nilotinib, and dasatinib. With a median follow up of 11.1 months, the probability to either maintain or improve their CCyR response was 56.6% (17/30) and 11 patients (36.7%) achieved or maintained their baseline MMR. In patients not having baseline CCyR, the probabilities of obtaining CCyR, MMR, and MR4.5 were 13, 11, and 14%, respectively. The probabilities of obtaining MMR and deep molecular response MR4.5 in patients with baseline CCyR were 40.0% (6/15) and 20.0% (3/15). At 20 months, progression-free survival was 73%. Grade 3-4 hematological toxicities were more frequent in resistant than intolerant patients (45.4 vs. 0.0%). Nonhematological toxicities were also more frequent in resistant patients, being diarrhea the most conspicuous one. Bosutinib seems to be an appropriate treatment option for patients resistant or intolerant to three prior TKI's.

BACKGROUND: Despite the excellent prognostic of chronic myeloid leukemia (CML) patients since the introduction of tyrosine kinase inhibitors (TKIs), approximately 50% of patients that are treated with TKIs will discontinue first line treatment due to lack of efficacy or intolerance. Once patients need a second line treatment, a considerable proportion of patients will need third or even fourth line therapy during further evolution. At this moment, there is a lack of data about real benefit of this group of patients. We have recently published our experience of 30 CML patients treated with bosutinib in 4th line. We present an update of the study where we have increased the number of patients, and the follow-up. The aim of this study is to present safety and efficacy data CML chronic phase patients treated with bosutinib in 4th line. METHODS: We have collected data from 59 CML patients treated with bosutinib in 4th line after resistance or intolerance to IM, NI and DA. 51 patients have been treated under the Spanish compassionate use program (36 centers) and 10 patients were treated in a single institution from United Kingdom. Median age of patients at diagnosis was 53 years. The percentage of low, intermediate and high risk Sokal groups were 47%, 37% and 16%. Median time TKIs exposure before bosutinib was 9 years. The most common indication (30/59) was intolerant to DA and NI. Patients' dispositions and main line characteristics are shown in table 1. RESULTS: Median follow-up was 14.3 months. All patients started bosutinib at 500mg/d, median dose of was 450mg/d. Overall probabilities to either achieve or maintain previous response were 96% (57/59), 62% (37/59), 40% (24/59) and 17% (10/59) for complete hematological response (CHR), complete cytogenetic response (CCyR), major molecular response (MMR) and MR4.5 respectively. However, probabilities to obtain responses (in patients without response evaluated at baseline) were 27% (7/26), 26% (12/45) and 12% (7/55) for CCyR, MMR and MR4.5. As expected, probabilities to obtain CCyR were lower for patients resistant to DA and NI patients than for patients intolerant to DA and NI (8% VS 44%). Event free survival (EFS) and progression free survival (PFS) probabilities were 50% and 83% by 27 month. Treatment was discontinued in 20/58 (34%), most frequent reasons being adverse events 9/59(15%), lack of efficacy 5/59 (8.5%), disease progression 2/59 (3.4%) and death 1/59 (1.7%). Two patients discontinued due to stem cell transplantation. The adverse events that led to treatment discontinuation were pleural effusion (3), diarrhea (2), rash, renal impairment, auricular fibrillation and liver enzyme elevation one patient each. Overall, bosutinib was well tolerated. Grade 3-4 hematological toxicities were 3%, 6% and 6% for anemia, thromboctytopenia and neutropenia. Most common non hematological side effects were diarrhea (39%, nauseas 13% and liver alterations 14% and pleural effusion 14%. CONCLUSIONS: Little is known about the therapeutic role of Bosutinib in 4th line. The series presented here is, to our knowledge, the largest being presented. Bosutinib seems to be an appropriate treatment option for patients resistant or intolerant to three prior TKIs. | | IM+NI-I+DA-R (N=4) | IM+NI-R+DA-R (N=18) | IM+NI-I+DA-I (N=30) | IM+NI-R+DA-I (N=7) | Total (N=59) | | ------------------------------------------------ | ----------------------- | ------------------------ | ----------------------- | ------------------------ | ------------------------- | ------------------------- | | Sex, N (%) Male | 2 (50) | 11 (61.1) | 16 (53.3) | 2 (28.6) | 31 (52.5) | | Median age of diagnosis, yr (range) | 57.32 (50-64) | 49.19 (23-73) | 54.95 (21-89) | 48.87 (26-68) | 53.15 (21-89) | | Median age of Bosutinib initiation, yr (range) | 69.13 (61-70) | 62.27 (39-79) | 64.85 (25-90) | 64.79(35-74) | 63.7 (25-9) | | Median follow up, months (range) | 18.5(7.8-34.1) | 8.4(1.22-36.1) | 16.3(0.5-34.7) | 23.4(3.3-28.9) | 14.3(0.7-36.1) | | SOKAL Index at diagnosis, N (%) | High | 2(50.0) | 4 (23.5) | 1 (4.3) | 1 (20) | 8 (16.3) | | Intermediate | 1 (25.0) | 5 (29.4) | 10(43.5) | 2 (40) | 18 (36.7) | | Low | 1 (25.0) | 8 (47.1) | 12 (52.2) | 2 (40) | 23 (46.9) | | Median Time from first TKI to BOS, (yr, range) | 10.3 (4.8-11.9) | 9.3 (2.0-11.4) | 8.8 (0.7-13.6) | 8.2 (5.1-12.3) | 8.8 (0.7-13.6) | | Median duration of prior therapy, months (range) | Imatinib | 38.8 (11.8-69.8) | 32.6 (6.3-96.8) | 26.2 (1.6-102.6) | 23.1 (8.3-66.8) | 28.8 (1.6-102.6) | | Dasatinib | 21.5 (12.6-75) | 21.8 (7.7-69) | 31.4 (0.4-87.1) | 23.7 (10.3-53.6) | 23.44 (0.4-87.1) | | Nilotinib | 19.1 (2.1-46.2) | 16.7 (5-65.6) | 8.9 (0.2-58.5) | 30.9 (6.9-49.3) | 14.3 (0.2-65.6) | * BOS: bosutinib, IM, imatinib; DA, dasatinib; NI, nilotinib, I: Intolerance, R: Resistant, Yr: year Table 1. Disclosures Garcia-Gutierrez: Ariad: Consultancy; Pfizer: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Milojkovic: Novartis: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Ariad: Consultancy, Honoraria; BMS: Consultancy, Honoraria. Boque: Novartis: Honoraria; BMS: Honoraria; Celgene: Honoraria. Casado: Novartis: Honoraria, Research Funding; BMS: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Roche: Honoraria, Research Funding. Jimenez: Pfizer: Consultancy, Honoraria. Giraldo: Pfizer: Consultancy. Steegmann: Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; BMS: Consultancy, Honoraria, Research Funding, Speakers Bureau; Pfizer: Consultancy, Honoraria, Research Funding, Speakers Bureau; Ariad: Consultancy, Honoraria, Research Funding, Speakers Bureau.

Second-generation TKIs have demonstrated efficacy and an acceptable tolerability in patients (pts) with chronic myeloid leukemia (CML); however, new data from so called “off target” side effects have been published. For example, serious concerns have been raised about cardiovascular (CV) events with ponatinib, and, in lesser degree with nilotinib (NI), impeding or difficulting the treatment in patients with previous CV risk factors. Besides, patients with previous history of pleural effusion or pulmonary hypertension should avoid dasatinib (DA) if possible. Bosutinib could be a good candidate for situations which preclude the use of other TKI’s. We have previously presented efficacy data of 29 patients treated with bosutinib in forth line. The aim of this study is to report safety data of heavily CML patients treated with bosutinib in 4th line. We have studied 30 pts previously treated with imatinib (IM), dasatinib and nilotinib and 5 pts previously treated with IM-DA or NI since 2012 under the Spanish Compassionate Use Program. Patient’s baseline characteristics and previous treatments are shown in table 1. We have classified patients in 2 groups regarding to investigator-driven cause of discontinuation: intolerant (INT) or resistant (RES). At the data cutoff on June 16, 2014, the median follow up was 11.47 months (range, 2.03-45.97 months). Median duration of BOS treatment across all cohorts was 9.23 months (range, 0.63-23.40 months). We observed no significant differences in terms of Index prognostic factors (Sokal, Hasford or Eutos), sex, median duration of TKIs treatment or comorbidities. However, patients with resistance where significantly older observed: 56 years vs. 67 years (p

Abstract 1412 Over the last decade, numerous new drugs have been incorporated in the treatment armamentarium of multiple myeloma (MM). However, there is not much information on the role of single nucleotide polymorphisms (SNPs) regarding toxicity and efficacy of the new myeloma therapies. Aims: to analyze the influence of genetic polymorphisms on toxicity and outcome of induction therapy on patients included in the trial of the Spanish PETHEMA/GEM 05 for newly diagnosed MM elderly patients (age 65 or more, “GEM05mas65”). (Lancet Oncol 2010; 11: 934). Patients and Methods: Between March, 2006, and October, 2008, 260 patients with untreated multiple myeloma, 65 years and older, from 63 Spanish centres, were randomly assigned to receive six cycles of botezomib plus melphalan and prednisone VMP (n=130) or bortezomib plus thalidomide and prednisone (VTP; n=130) as induction therapy. Genetic studies were performed in blood samples from 169 patients among the 260 included in the original trial (VMP: 84 patients; VTP: 85 patients). Toxicity and outcome parameters were analyzed and related to the genotype of polymorphisms in genes involved in bortezomib (CYP1A2 *1C, CYP1A2 *1F, CYP3A4), thalidomide (CYP2C19 *2, CYP2C19 *17) and melphalan metabolism (GSTP1 I105V) as well as bortezomib transport (MDR1 −3435C>T) and drug target (PSMB5 1042G>A). Results: Clinical results in our cohort reproduced those of the 260 patients of the original trial already published. The most frequent non haematological toxicity was peripheral neuropathy, similar in both arms. Among the 169 patients included in our study CYP2C19 *17 T carriers had worse overall response (p=0.033). Likewise, MRD1 −3435TT carriers presented less incidence of grade 3–4 neutropenia (p=0.041) meanwhile patients AA for CYP2C19 *2 genotype presented more grade 3–4 thrombopenia (p=0.009). The impact of the different genotypes among the two arms and inside each one was also analyzed. Wild type patients for MRD1 −3435T SNP displayed higher rate of severe neutropenia only in the VMP arm and in a genetic load depending manner (CC=71%, CT=38%, TT=22%; p= 0.012). Conclusions: Our results suggest that polymorphisms in genes involved in the metabolism of thalidomide, (CYP2C19 *17 y *2) or bortezomib transport (MDR1 −3435C>T) may result in a thalidomide modified metabolism rate or in a lower efficacy in the bortezomib transport, suggesting a potential influence in the haematological toxicity (neutropenia and thrombopenia) and overall response rates in MM patients treated with VMP or VTP. These results together with the relative elevated frequency of these SNPs in this population (>20%) justifies the interest of studying the genetic profile since it can become a step forward on the individualized management of MM patients. Disclosures: Mateos: Celgene: Honoraria; Janssen: Honoraria. Lahuerta:Janssen: Honoraria; Celgene: Honoraria. Blade:Janssen: Honoraria; Celgene: Honoraria.

INTRODUCTION: In chronic myeloid leukemia (CML) patients in chronic phase (CML-CP), BCR-ABL levels ≤10% at 3 months measured by RT-qPCR (IS) has been consistently correlated with probabilities to obtain an optimal response at 12 months. Monitoring molecular response with automated cartridge-based detection system GeneXpert BCR-ABL (Cepheid®) method has shown an optimal correlation with standardized BCR-ABL (IS) EUTOS method in patients with complete cytogenetic response (CCyR). However, is not known if both methods are also equivalent when measuring BCR-ABL levels above 1%, and therefore, the utility of GeneXpert in order to evaluate response at 3 months must be confirmed. AIMS: To validate the predictive value of molecular response at 3 months with GeneXpert method METHODS: We have studied 125 new consecutive CML-CP patients treated with tyrosine kinase inhibitors (TKIs) followed in 13 centers. Median age at diagnosed was 55 years. The percentage of low, intermediate and high risk Sokal groups were 42%, 40% and 18% . First line treatment was imatinib (IM), nilotinib (NI), dasatinib (DA) or bosutinib (BO) in 58%, 28%, 13% and 1% of the patients, respectively. BCR-ABL level was measured by GeneXpert platform, where all necessary steps to measure BCR-ABL levels are automatically performed. ABL was used as gene control. The study was approved by the Ethics Committee. RESULTS: Median follow up was 43 months. The proportion of patients that achieved CCyR by 12 months, analyzed by intention to treat, was 84% (108/123). Probabilities for each specific TKI were 78%, 93%, 100% and 100% for IM, NI, DA and BO respectively. 23% (96/125) of patients required treatment changed due to resistance or intolerance. Treatment discontinuation probabilities were 32%, 11%, 5% and 0% for IM, NI, DA and BO respectively. Only 4% (5/125) did not achieve an optimal response at 3 months (BCR-ABL ≤10%), which is significant lower compare to results obtain with historical series when using EUTOS IS method. 10% cut-off at 3 month was unable to identify patients that achieved an optimal response in further evaluations. By 12 months, this cutoff did not correlate with probabilities to obtain CCyR (50% vs 86% (p=0.1) or major molecular response (MMR) (60% vs 79% (p=0.21)). In order to find a cutoff that could correlate with optimal response at 12 months, we used a receiver operating characteristic curve to identify the optimal cutoff in transcript level that would allow us to classify the patients as high risk or low risk with maximal sensitivity and specificity for each individual outcome. At 3 months, patients with transcript levels ≤ 1.6% had significantly better probabilities to obtain an optimal response by 12 months, with 81% and 94% sensitivity and specificity for CCyR. With this new cutoff, probabilities for CCyR and MMR at 12 months were 98% vs 54% (p CONCLUSIONS: The results of our study seem to show that the 10% threshold, commonly used to evaluate response at 3 months when using BCR-ABL (IS) EUTOS method, is not associated with probabilities to achieve further optimal responses when using the GeneXpert platform. We have shown how a new cutoff of 1,6% % at 3 months when using GeneXpert could better identify patients with lower risk to achieve an optimal response at 12 months. Disclosures García-Gutierrez: Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Ariad: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Steegmann:Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; BMS: Consultancy, Honoraria, Research Funding, Speakers Bureau; Pfizer: Consultancy, Honoraria, Research Funding, Speakers Bureau; Ariad: Consultancy, Honoraria, Research Funding, Speakers Bureau.