Search

BACKGROUND: Patients with metastatic colorectal cancer with the BRAF V600E mutation have a poor prognosis, with a median overall survival of 4 to 6 months after failure of initial therapy. Inhibition of BRAF alone has limited activity because of pathway reactivation through epidermal growth factor receptor signaling. METHODS: In this open-label, phase 3 trial, we enrolled 665 patients with BRAF V600E-mutated metastatic colorectal cancer who had had disease progression after one or two previous regimens. Patients were randomly assigned in a 1:1:1 ratio to receive encorafenib, binimetinib, and cetuximab (triplet-therapy group); encorafenib and cetuximab (doublet-therapy group); or the investigators' choice of either cetuximab and irinotecan or cetuximab and FOLFIRI (folinic acid, fluorouracil, and irinotecan) (control group). The primary end points were overall survival and objective response rate in the triplet-therapy group as compared with the control group. A secondary end point was overall survival in the doublet-therapy group as compared with the control group. We report here the results of a prespecified interim analysis. RESULTS: The median overall survival was 9.0 months in the triplet-therapy group and 5.4 months in the control group (hazard ratio for death, 0.52; 95% confidence interval [CI], 0.39 to 0.70; P

PURPOSE BEACON CRC evaluated encorafenib plus cetuximab with or without binimetinib versus investigators' choice of irinotecan or FOLFIRI plus cetuximab in patients with BRAFV600E–mutant metastatic colorectal cancer (mCRC), after progression on 1-2 prior regimens. In the previously reported primary analysis, encorafenib, binimetinib plus cetuximab (ENCO/BINI/CETUX; triplet) and encorafenib plus cetuximab (ENCO/CETUX; doublet) regimens improved overall survival (OS) and objective response rate (ORR; by blinded central review) versus standard of care. The purpose of this analysis was to report updated efficacy and safety data. METHODS In this open-label, phase III trial, 665 patients with BRAF V600E–mutant mCRC were randomly assigned 1:1:1 to receive triplet, doublet, or control. Primary end points were OS and independently reviewed ORR comparing triplet to control. OS for doublet versus control was a key secondary end point. Updated analyses include 6 months of additional follow-up and ORR for all randomized patients. RESULTS Patients received triplet (n = 224), doublet (n = 220), or control (n = 221). Median OS was 9.3 months (95% CI, 8.2 to 10.8) for triplet and 5.9 months (95% CI, 5.1 to 7.1) for control (hazard ratio [HR], 0.60 [95% CI, 0.47 to 0.75]). Median OS for doublet was 9.3 months (95% CI, 8.0 to 11.3) (HR v control, 0.61 [95% CI, 0.48 to 0.77]). Confirmed ORR was 26.8% (95% CI, 21.1% to 33.1%) for triplet, 19.5% (95% CI, 14.5% to 25.4%) for doublet, and 1.8% (95% CI, 0.5% to 4.6%) for control. Adverse events were consistent with the prior primary analysis, with grade ≥ 3 adverse events in 65.8%, 57.4%, and 64.2% for triplet, doublet, and control, respectively. CONCLUSION In the BEACON CRC study, encorafenib plus cetuximab improved OS, ORR, and progression-free survival in previously treated patients in the metastatic setting compared with standard chemotherapy. Based on the primary and updated analyses, encorafenib plus cetuximab is a new standard care regimen for previously treated patients with BRAF V600E mCRC.

In COLUMBUS, treatment with encorafenib plus binimetinib in patients with advanced BRAF-mutant melanoma showed improved progression-free and overall survival with favourable tolerability compared to vemurafenib treatment. Here, results on health-related quality of life (HRQoL) are presented.COLUMBUS was a two-part, open-label, randomised, phase III study in patients with BRAF-mutant melanoma. In PART-I, 577 patients were randomised (1:1:1) to encorafenib plus binimetinib, encorafenib or vemurafenib. The primary objective was to assess progression-free survival. As a secondary objective, HRQoL was assessed by the EQ-5D, the EORTC QLQ-C30 and the FACT-M questionnaires. Furthermore, time to definitive 10% deterioration was estimated with a Kaplan-Meier analysis and differences in mean scores between groups were calculated with a mixed-effect model for repeated measures. Hospitalisation rate and the impact of hospitalisation on HRQoL were also assessed.Patients receiving the combination treatment showed improvement of their FACT-M and EORTC QLQ-C30 global health status scores, compared to those receiving vemurafenib (post-baseline score differences: 3.03 [p 0.0001] for FACT M and 5.28 [p = 0.0042] for EORTC QLQ-C30), indicative of a meaningful change in patient's status. Furthermore, a delay in the deterioration of QoL was observed in non-hospitalised patients compared to hospitalised patients (hazard ratio [95% CI]: 1.16 [0.80; 1.68] for EORTC QLQ-C30 and 1.27 [0.81; 1.99] for FACT-M) and a risk reduction of 10% deterioration, favoured the combination in both groups.The improved efficacy of encorafenib plus binimetinib compared to vemurafenib, translates into a positive impact on the perceived health status as assessed by the HRQoL questionnaires. The study is registered with ClinicalTrials.gov, number NCT01909453 and EudraCT number 2013-001176-38.

PURPOSE To determine the safety and preliminary efficacy of selective combination targeted therapy for BRAF V600E–mutant metastatic colorectal cancer (mCRC) in the safety lead-in phase of the open-label, randomized, three-arm, phase III BEACON Colorectal Cancer trial ( ClinicalTrials.gov identifier: NCT02928224; European Union Clinical Trials Register identifier: EudraCT2015-005805-35). PATIENTS AND METHODS Before initiation of the randomized portion of the BEACON Colorectal Cancer trial, 30 patients with BRAF V600E–mutant mCRC who had experienced treatment failure with one or two prior regimens were to be recruited to a safety lead-in of encorafenib 300 mg daily, binimetinib 45 mg twice daily, plus standard weekly cetuximab. The primary end point was safety, including the incidence of dose-limiting toxicities. Efficacy end points included overall response rate, progression-free survival, and overall survival. RESULTS Among the 30 treated patients, dose-limiting toxicities occurred in five patients and included serous retinopathy (n = 2), reversible decreased left ventricular ejection fraction (n = 1), and cetuximab-related infusion reactions (n = 2). The most common grade 3 or 4 adverse events were fatigue (13%), anemia (10%), increased creatine phosphokinase (10%), increased AST (10%), and urinary tract infections (10%). In 29 patients with BRAF V600E–mutant tumors (one patient had a non– BRAF V600E–mutant tumor and was not included in the efficacy analysis), the confirmed overall response rate was 48% (95% CI, 29.4% to 67.5%), median progression-free survival was 8.0 months (95% CI, 5.6 to 9.3 months), and median overall survival was 15.3 months (95% CI, 9.6 months to not reached), with median duration of follow-up of 18.2 months (range, 16.6 to 19.8 months). CONCLUSION In the safety lead-in, the safety and tolerability of the encorafenib, binimetinib, and cetuximab regimen is manageable and acceptable for initiation of the randomized portion of the study. The observed efficacy is promising compared with available therapies and, if confirmed in the randomized portion of the trial, could establish this regimen as a new standard of care for previously treated BRAF V600E–mutant mCRC.

Signal Transducer and Activator of Transcription 3 (STAT3) plays important roles in the transduction of signals from growth factors and cytokines in both normal and malignant cells. Upon activation, STAT3 controls expression of genes that regulate cell growth, survival, differentiation, stemness and cell-cell interactions. Aberrant activation of STAT3 has been observed in many cancers including lymphoma and leukemias through activating mutations, hyper-signaling through upstream regulators or loss of negative feedback regulation. Additionally, STAT3-mediated cross-talk in the tumor microenvironment results in suppression of immune surveillance compromising anti-tumor immunity. STAT3 has been historically considered "undruggable". Heterobifunctional degraders that recruit endogenous E3 ligases to ubiquitinate substrate proteins leading to their degradation by the proteosome have emerged as a novel therapeutic modality with great potentials to drug undrugged protein targets. Here we introduce a first-in-class, potent and selective STAT3 degrader KT-333 that is being developed for the treatment of hematologic malignancies and solid tumors. KT-333 is a small molecule targeted protein degrader of STAT3 and was discovered by an iterative medicinal chemistry SAR campaign improving parameters such as potency, selectivity and ADME profile. It has high solubility in PBS buffer (103 mg/mL, pH7.4). low to moderate clearance in rat, dog and monkey, and moderate plasma half lives across pre-clinical species. KT-333 exhibits potent and selective degradation of STAT3 with DC 50 of 2.5 -11.8 nM in four anaplastic T cell lymphoma (ALCL) lines. Selective degradation of STAT3 over nearly 9000 proteins, including other STAT family members, was demonstrated by mass spectrometry in human PBMCs . Tumor cells expressing NPM-ALK fusion oncoproteins have activated STAT3 and dependency on STAT3 signaling for survival KT-333 treatment led to rapid apoptosis of these ALK+ALCL cells. To better understand the cellular responses to STAT3 degradation, time-course transcriptomic and proteomic analyses were performed using SU-DHL-1 cells treated with KT-333. Time-dependent changes in both mRNA and protein levels of STAT3-regulated genes and pathways were observed: at 8 h only STAT3 showed significant depletion, at 24 h canonical STAT3 downstream genes including SOCS3, IL-2RA and GRZMB showed modulation and at 48 h, pathways including interferon response and cell cycle were significantly enriched. A comparison of the transcriptomic and proteomic data sets showed high correlation. Furthermore, changes in mRNA and protein levels of bona fide STAT3 regulated targets showed a high degree of concordance between SU-DHL-1 cells and SU-DHL-1 xenograft tumors. Preclinical in vitro experiments have demonstrated that approximately 90% degradation of STAT3 for 48 h was sufficient to drive ALK+ ALCL lines into irreversible cell growth inhibition and death. In vivo xenograft studies of SU-DHL-1 and SUP-M2 ALCL models demonstrated dose-dependent tumor growth suppression. An indirect response model that linked exposure to target degradation was established to describe the relationship between exposure and target degradation in the tumor. Consistent with the in vitro data, PK-PD-efficacy analysis in the SU-DHL-1 xenograft model showed that tumor regression could be achieved with intermittent dosing schedules that achieved ~90% degradation of STAT3 for about 48 h over a weekly or bi-weekly dosing interval. . Based on preclinical ADME and PK/PD/efficacy relationship, KT-333 is predicted to drive tumor regression using weekly doses. In conclusion, we have identified a potent STAT3 degrader as development candidate that can be administered parenterally in the clinic on an intermittent dosing regimen that is predicted to be both efficacious and tolerated in STAT3-dependent hematologic malignancies. Disclosures Liu: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Dixit: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Mayo: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Dey: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Yuan: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Karnik: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Walther: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Shi: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Sharma: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Rong: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Yang: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Gollerkeri: BEAM Therapeutics: Current Employment, Current equity holder in publicly-traded company; Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. Gollob: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company. DeSavi: Kymera Therapeutics: Current Employment, Current equity holder in publicly-traded company.

Background Dual inhibition of the mitogen-activated protein kinase pathway with BRAF/MEK inhibitor (BRAFi/MEKi) therapy is a standard treatment for BRAFV600-mutant metastatic melanoma and has historically been associated with grade III pyrexia or photosensitivity depending on the combination used. The objective of this study was to fully describe adverse events from the COLUMBUS study evaluating the most recent BRAF/MEK inhibitor combination encorafenib+binimetinib. Patients and methods Patients with locally advanced, unresectable or metastatic BRAFV600-mutant melanoma were randomised to receive encorafenib 450 mg once daily plus binimetinib 45 mg twice daily, encorafenib 300 mg once daily or vemurafenib 960 mg twice daily. Adverse events that represent known effects of available BRAFi and/or MEKi were evaluated. Results The safety population included a total of 570 patients (encorafenib+binimetinib = 192; encorafenib = 192; vemurafenib = 186). Median duration of exposure was longer with encorafenib+binimetinib (51 weeks) than with encorafenib (31 weeks) or vemurafenib (27 weeks). Common BRAFi/MEKi toxicities with encorafenib+binimetinib were generally manageable, reversible and infrequently associated with discontinuation. Pyrexia was less frequent with encorafenib+binimetinib (18%) and encorafenib (16%) than with vemurafenib (30%) and occurred later in the course of therapy with encorafenib+binimetinib (median time to first onset: 85 days versus 2.5 days and 19 days, respectively). The incidence of photosensitivity was lower with encorafenib+binimetinib (5%) and encorafenib (4%) than with vemurafenib (30%). The incidence of serous retinopathy was higher with encorafenib+binimetinib (20%) than with encorafenib (2%) or vemurafenib (2%), but no patients discontinued encorafenib+binimetinib because of this event. Conclusion Encorafenib+binimetinib is generally well tolerated and has a low discontinuation rate in patients with BRAFV600-mutant melanoma, with a distinct safety profile as compared with other anti-BRAF/MEK targeted therapies. Trial registration ClinicalTrials.gov (Identifier: NCT01909453 ) and with EudraCT (number 2013-001176-38).

TPS3619 Background: Approximately 10% of patients (pts) with mCRC have BRAF mutations (mostly V600E). 1L tx options for BRAFV600E mCRC are limited to cytotoxic chemotherapy ± anti-VEGF or anti-EGFR, or immune checkpoint inhibitors in pts with MSI-H tumors. In Europe, Japan, and USA, the combination of BRAF inhibitor enco + EGFR inhibitor cetux is approved for tx of BRAFV600E mCRC after prior therapy. In BEACON CRC, enco + cetux resulted in a median overall survival (OS) of 9.3 months (95% confidence interval [CI]: 8.0–11.3) and an objective response rate (ORR) of 19.5% (95% CI: 14.5%–25.4%) in previously treated pts with BRAFV600E mCRC (median follow-up: 12.8 months); 57.4% of pts had grade 3/4 adverse events (AEs); 9% discontinued due to AEs. Given the poor prognosis of pts with BRAFV600E mCRC and based on the efficacy and tolerability of enco + cetux from BEACON CRC, BREAKWATER will evaluate efficacy and safety of enco + cetux ± chemotherapy in tx-naive pts with BRAFV600E mCRC. Methods: BREAKWATER is an open-label, global, multicenter, randomized, phase 3 study with a safety lead-in (SLI). Approximately 60 and 870 pts will be enrolled in the SLI and phase 3 parts of the study, respectively. Pts must have BRAFV600E mCRC (determined using tumor tissue or blood); ECOG performance status 0/1; and adequate bone marrow, hepatic, and renal function. Pts in the SLI must have evaluable disease (RECIST v1.1) and have received ≤ 1 prior tx regimen; those previously treated with a BRAF or EGFR inhibitor, or both oxaliplatin and irinotecan, will be excluded. Pts in the phase 3 study must have measurable disease and be tx naive for metastatic disease. Study tx and endpoints are shown in the table. Enrollment began on 6 January 2021. Clinical trial information: NCT04607421. [Table: see text]

3583 Background: Enco + cetux (doublet) has been approved in the US, EU, and Japan for the treatment of BRAF V600E-mutant mCRC after progression on 1–2 prior regimens. In the BEACON CRC study (NCT02928224), median OS (95% CI) with the doublet was 9.3 months (8.0–11.3) compared with 5.9 months (5.1–7.1) with cetux + irinotecan or FOLFIRI (control) in patients (pts) with BRAF V600E-mutant mCRC (HR 0.61 [95% CI: 0.5–0.8]). This post-hoc analysis investigates OS by prior therapies to the doublet treatment in pts with BRAF V600E-mutant mCRC from the BEACON CRC study. Methods: OS of pts treated with the doublet or control were compared according to prior treatment with bevacizumab, oxaliplatin, or FOLFOXIRI and duration of prior anticancer therapy (ACT). Results: The proportion of pts in the doublet and control arms who received prior bevacizumab were 64% and 55%, respectively. Of pts who had one prior therapy, 95% and 88% received prior oxaliplatin and 20% and 14% received prior FOLFOXIRI, respectively. OS by prior treatment in the doublet and control arms is shown in the table. In the doublet arm, pts who had bevacizumab < 4 months before start of study treatment had a median OS of 8.3 months (95% CI: 6.2–11.2); those who had bevacizumab ≥4 months prior had a median OS of 10.7 (95% CI: 7.5–17.7). Within each treatment arm, OS was similar regardless of prior treatment with oxaliplatin or FOLFOXIRI. The duration of prior ACT was similar across study arms, ranging from 5.6–5.8 months for the first line of ACT. Conclusions: In the BEACON CRC study, pts treated with the doublet for BRAF V600E-mutant mCRC demonstrated similar OS regardless of prior therapies or duration of prior therapy use. This exploratory post-hoc analysis provides data that reflect the prior treatment landscape clinicians may face when deciding subsequent treatment regimens for pts with BRAF V600E-mutant mCRC. Clinical trial information: NCT02928224. [Table: see text]

128 Background:The BRAF V600E mutation is a marker of poor prognosis in patients with metastatic colorectal cancer (mCRC). Targeted therapy, such as encorafenib plus cetuximab, is approved in the US/Europe for the treatment (tx) of BRAF V600E-mutated mCRC and demonstrated improved survival vs historical standard of care (SOC). Determining BRAF mutation status in mCRC is recommended by NCCN and ESMO guidelines although adherence to guidelines may not be uniform. This report’s objective is to communicate global survey results of mCRC BRAF testing practices. Identifying regions where BRAF testing is not SOC may help identify where education efforts are needed improve effective tx decision making. Methods: Oncology tx centers were identified from a registry and public information. Centers were selected for research experience, historic data quality, and estimated mCRC patients. A BRAF testing practices survey using an online platform of verified centers was conducted March-August 2020; 395 centers/38 countries have responded thus far. Results: Respondents indicated BRAF-mutation testing is performed as SOC for patients with mCRC in most regions; Eastern Europe and South America are exceptions: only 47% (45/95) and 45% (9/20) of centers, respectively routinely performed mutation testing. Most test tumor tissue, few test both tumor tissue or blood, and none conduct blood mutation testing only. Most regions perform BRAF testing at initial diagnosis or confirmation of advanced disease. Individual country statistics will be presented. Conclusions: BRAF testing has global variability, impacting tx decisions. Increased awareness and routine testing may lead to informed decisions regarding targeted therapies, such as encorafenib plus cetuximab where approved, in patients with BRAF V600E-mutant mCRC. [Table: see text]

10022 Background: LOGIC2 evaluates the benefit of a 3rd agent added to encorafenib (enco)/binimetinib (bini), selected at progression based on the genetic tumor evolution. Methods: In part I/run-In, pts were treated with enco/bini until disease progression (as defined per RECIST v1.1). Foundation One NGS was applied on a baseline sample and on a PD sample. Based on the genetic evolution between the biopsy at inclusion (bxI) and at progression (bxPD) and clinical considerations, pts entered part II and received one of four 3rd agent additions to enco/bini combinations: A. LEE011 (CDK4/6 inhibitor), B. BKM120 (PI3K inhibitor), C. INC280 (c-Met inhibitor), or D. BGJ398 (FGFR inhibitor). An adaptive Bayesian logistic regression model (BLRM) guided by the escalation with overdose control (EWOC) principle was used to make dose escalation decisions. Assessments include objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), and safety. Data cutoff for this analysis was May 12, 2019. Data is as is. Part 1 of study is ongoing. Part 2 of study is closed to enrollment. Results: 58 pts enrolled into part II (group A=38; B=6; C=13; D=1). 29 pts were assigned to treatment based on bxPD results (Table). In groups A, B, and C, the confirmed ORR was 5.3%, 0%, and 0%, and the DCR was 26.3%, 16.7%, and 15.4%, with median PFS of 2.1, 1.6, and 2.2 months, respectively. Safety was consistent with known profiles of the individual agents. Conclusions: Triple therapy is feasible when a 3rd agent is added to enco/bini at progression based on genetic alterations, although activity observed was low. Further exploration to identify patterns of resistance susceptible to the addition of a 3rd agent is needed. Gene alterations for enrollment into part 2. Clinical trial information: NCT02159066. [Table: see text]

4001 Background: BEACON CRC is a randomized, phase 3 study which evaluated the triplet of encorafenib (ENCO) + binimetinib (BINI) + cetuximab (CETUX) and the doublet of ENCO + CETUX vs. investigator’s choice of irinotecan + CETUX or FOLFIRI + CETUX in patients (pts) with BRAFV600E metastatic colorectal cancer (mCRC) whose disease had progressed after 1-2 prior regimens in the metastatic setting. Primary endpoints were overall survival (OS) and objective response rate (ORR; by blinded central review) for triplet vs control. In a previous interim analysis, triplet and doublet improved OS and ORR versus standard of care. Here we report on an updated analysis. Methods: Updated analysis includes 6 months of additional follow-up and response data for all randomized pts. The study is ongoing. Results: Pts received triplet (n=224), doublet (n=220), or control (n=221). Median OS was 9.3 months (95% confidence interval [CI]:8.2, 10.8) for triplet and 5.9 months (95% CI:5.1-7.1) for control (hazard ratio [HR] (95% CI): 0.60 (0.47-0.75)). Median OS for doublet was 9.3 months (95% CI: 8.0-11.3) (HR vs. control: 0.61 (0.48-0.77). Confirmed ORR was 26.8% (95% CI: 21.1%-33.1%) for triplet, 19.5% (95% CI: 14.5%-25.4%) for doublet, and 1.8% (95% CI: 0.5%-4.6%) for control. Retrospective subgroup analyses suggested some pts may benefit more from triplet than doublet therapy (Table). Both triplet and doublet showed improved OS compared to control in all subgroups. Adverse events were consistent with prior analysis, with grade ≥3 adverse events in 65.8%, 57.4%, and 64.2% for triplet, doublet and control, respectively. Conclusions: The updated analysis of the BEACON CRC study confirmed that encorafenib + cetuximab with or without binimetinib improved OS and ORR in previously treated pts with BRAF V600E mCRC compared with standard chemotherapy. Clinical trial information: NCT02928224 . [Table: see text]

10012 Background: Treatment of patients with BRAF V600–mutant melanoma includes BRAF/MEK-inhibitor combinations based on demonstrated benefits on progression-free survival (PFS) and overall survival (OS). To better understand the proportion of patients who derive long-lived benefit and their characteristics, we performed an updated analysis of OS and other endpoints from the COLUMBUS trial. Methods: In Part 1 of COLUMBUS, 577 patients with advanced/metastatic BRAF V600‒mutant melanoma, untreated or progressed after first-line immunotherapy, were randomized 1:1:1 to ENCO 450 mg QD + BINI 45 mg BID (COMBO450) vs VEM 960 mg BID (VEM) or ENCO 300 mg QD (ENCO300). An updated analysis including PFS, OS, objective response rate (ORR), and safety was conducted after an additional 24 months’ follow-up from the initial analysis. The study is ongoing. Results: At data cutoff (November 2019, as-is data), events had occurred in 65%, 59%, and 75% of patients in the COMBO450, ENCO300, and VEM treatment arms, respectively. Across arms, median follow-up for OS was 60.6 months (mo), with median OS of 33.6 mo (95% CI, 24.4–39.2) for COMBO450, 23.5 mo (95% CI, 19.6–33.6) for ENCO300, and 16.9 mo (95% CI, 14.0–24.5) for VEM. Compared to VEM, COMBO450 decreased the risk of death by 38% (HR, 0.62 [95% CI, 0.49–0.79]). Updated median PFS was COMBO450, 14.9 mo (95% CI, 11.0–20.2), ENCO300, 9.6 mo (95% CI, 7.4–14.8), and VEM, 7.3 mo (95% CI, 5.6–7.9). PFS was longer for COMBO450 vs VEM (HR, 0.52 [95% CI, 0.40–0.67]). A landmark analysis showed a higher rate of OS for COMBO450 at each year analyzed, with OS rates at 4 years of 39%, 37%, and 26% COMBO450, ENCO300, and VEM, respectively. Updated safety analysis confirmed the beneficial long-term tolerability of COMBO450. Conclusions: In the COLUMBUS trial, results for updated PFS and OS with COMBO450 continue to demonstrate long-term benefits in patients with BRAF V600‒mutated melanoma. Clinical trial information: NCT01909453.

4039 Background: In the BEACON CRC study, the triplet regimen of encorafenib (ENCO) + binimetinib (BINI) + cetuximab (CETUX) significantly improved overall survival (OS, HR:0.52, P < 0.0001) and objective response rates (ORR, 26% vs 2%, P < 0.0001) in patients (pts) with BRAFV600E metastatic colorectal cancer (mCRC) compared with current standard of care. This analysis focuses on the patient-reported quality of life (QOL) assessments from this study. Methods: The BEACON CRC study was a randomized, open-label, 3-arm, phase 3 global study which evaluated triplet (ENCO+BINI+CETUX) or doublet (ENCO+CETUX) vs. investigator’s choice of irinotecan + CETUX or FOLFIRI + CETUX in pts with BRAFV600E mCRC. QOL assessments (secondary endpoints in the trial) included the EORTC QOL Questionnaire (QLQ C30), Functional Assessment of Cancer Therapy Colon Cancer (FACT C), EuroQol 5D 5L, and Patient Global Impression of Change (PGIC). The primary assessment for the QOL variables was the time to definitive 10% deterioration. The study is ongoing. Results: 665 pts were randomly assigned to receive either triplet (n = 224), doublet (n = 220), or control (n = 221). Reduction in the risk of QOL deterioration was an estimated 45% (HR 0.55, 95% CI: 0.43, 0.70) and 52% (HR 0., 9485% CI: 0.38, 0.62) in EORTC QLQ C30 and FACT C assessments, respectively, in favor of the triplet regimen over control. For the doublet vs. control, reduction in risk of QOL deterioration was an estimated 46% (HR 0.54, 95% CI: 0.43, 0.69) and 54% (HR 0.46, 95% CI: 0.36, 0.59) in EORTC QLQ C30 and FACT C, respectively in favor of the doublet. Similar results were observed in EuroQol 5D 5L and PGIC assessments. There were no overall differences in QOL between triplet and doublet across the 4 instruments. Conclusions: In BEACON CRC, triplet and doublet demonstrated substantial improvement in patient-reported QOL assessments over the current standard of care in pts with BRAFV600E-mutant metastatic CRC whose disease had progressed after 1 or 2 prior regimens. Clinical trial information: NCT02928224 .

688 Background: BRAFV600E mutation occurs in 10%-–15% of patients (pts) with mCRC and confers a poor prognosis. After first-line therapy, standard second-line therapies provide limited benefit, with objective response rates (ORRs) < 10%, and overall survival (OS) of 4–6 months (mo). BEACON CRC (NCT02928224) is a 3-arm phase 3 trial of triplet therapy with the BRAF inhibitor ENCO + MEK inhibitor BINI + anti–EGFR antibody CETUX vs ENCO + CETUX vs a control arm (irinotecan/FOLFIRI + CETUX) in pts with BRAFV600E mCRC in the second or third-line setting. A safety lead-in (SLI) of the triplet therapy was conducted in 30 pts prior to initiation of the randomized part of the trial. Previously reported confirmed ORR in 29 pts with BRAFV600E mCRC was 48% and median progression-free survival (PFS) was 8.0 mo (Van Cutsem E, et al. Ann Oncol. 2018;29:O-027). Here we present updated safety and efficacy results including mature OS. Methods: All pts in the SLI received ENCO 300 mg once daily + BINI 45 mg twice daily + CETUX standard weekly dose. Assessments included efficacy (ORR, duration of response, time to response, PFS, and OS), safety, and tolerability. Results: Among 30 pts treated, 1 had a BRAF non-V600E mutation and is not included in the efficacy analyses. At data cutoff, the median follow-up time for survival was 18.2 mo and median exposure was 7.8 mo (range 0.5–21.4 mo). The confirmed ORR and median PFS remain unchanged from the previous report (ORR, 48% [95%CI, 29.4–67.5]; PFS, 8.0 mo [95% CI, 5.6–9.3 mo]). Mature median OS is 15.3 mo (95% CI, 9.6 mo–not reached). The triplet continues to be well-tolerated with no unexpected toxicities. The most common grade 3/4 toxicities were fatigue (13%), anemia, increases in creatine phosphokinase and/or aspartate aminotransferase, and urinary tract infections (each 10%). The rate of grade 3/4 skin toxicities continues to be lower than generally observed with CETUX in mCRC. Conclusions: With longer follow-up, triplet therapy with ENCO + BINI + CETUX continues to be well tolerated. Median PFS and now mature median OS are substantially improved over historical data for current standard-of-care options. Clinical trial information: NCT02928224.

Patients with Philadelphia (Ph) chromosome–positive acute lymphoblastic leukemia (ALL) have a rapid disease course and a poor prognosis. Dasatinib, a novel, oral, multitargeted kinase inhibitor of BCR-ABL and SRC family kinases, has previously induced responses in patients with imatinib-resistant or -intolerant Ph-positive ALL. We present the interim results of a phase 2 study designed to further assess the efficacy, safety, and tolerability of dasatinib 140 mg in this patient population (n = 36). With a minimum follow-up of 8 months, treatment with dasatinib resulted in substantial hematologic and cytogenetic response rates. Major hematologic responses were achieved in 42% (15/36) of patients, 67% of whom remained progression-free. Complete cytogenetic responses were attained by 58% (21/36) of patients. The presence of BCR-ABL mutations conferring imatinib resistance did not preclude a response to dasatinib. Dasatinib was also tolerable, with 6% (2/36) of patients discontinuing therapy as a result of study-drug toxicity. Most adverse events (AEs) were grade 1 or 2; febrile neutropenia was the most frequent severe AE, but this and other cytopenias were manageable with dose reduction. Dasatinib represents a safe and effective treatment option and an important therapeutic advance for patients with Ph-positive ALL. This trial was registered at www.clinicaltrials.gov as #CA180015.

Objective PF-04691502 and gedatolisib (PF-05212384) are potent, dual PI3K/mTOR inhibitors. This phase II study (B1271004) was conducted in patients with recurrent endometrial cancer following platinum-containing chemotherapy. The primary endpoint was to assess clinical benefit response (complete or partial response, or stable disease for ≥16weeks) following treatment with PF-04691502 or gedatolisib. Methods The main study consisted of four independent arms based on a Simon two-stage design. Patients were assigned to putative PI3K-basal (PF-04691502 or gedatolisib) or PI3K-activated (PF-04691502 or gedatolisib) arms based on stathmin-low or stathmin-high tumor expression, respectively. Japanese patients were also enrolled in a separate lead-in cohort. Results In stage 1 (main study), eighteen patients were randomized to PF-04691502 and 40 to gedatolisib. The two PF-04691502 arms were discontinued early due to unacceptable toxicity, including pneumonia and pneumonitis. The most common treatment-related adverse events associated with gedatolisib were nausea (53%), mucosal inflammation (50%), decreased appetite (40%), diarrhea (38%), fatigue (35%), and dysgeusia and vomiting (each 30%). Clinical benefit response rate was 53% (10/19) in the gedatolisib/stathmin-low arm and 26% (5/19) in the gedatolisib/stathmin-high arm. Safety profile and pharmacokinetic characteristics of both drugs in the Japanese lead-in cohort were comparable to the Western population. Conclusions Gedatolisib administered by weekly intravenous infusion demonstrated acceptable tolerability and moderate activity in patients with recurrent endometrial cancer. PF-04691502 daily oral dosing was not well tolerated. Clinical benefit response criteria for proceeding to stage 2 were only met in the gedatolisib/stathmin-low arm. Stathmin-high expression did not correlate with greater treatment efficacy. ClinicalTrials.gov registration ID: NCT01420081.

9567Background: Combination BRAF/MEK inhibitor (BRAFi/MEKi) therapy is standard of care for BRAFV600-mutant metastatic melanoma. In COLUMBUS Part 1, encorafenib 450 mg once daily (QD) + binimetinib...

627 Background: The SLI of the BEACON CRC phase 3 study assessed the safety and efficacy of the combination of the BRAF inhibitor encorafenib (ENCO) + MEK inhibitor binimetinib (BINI) + anti-EGFR antibody cetuximab (CETUX) in pts with BRAFV600E-mutant mCRC after 1 or 2 prior regimens. CEA and CA19-9 are tumor markers that are widely used to monitor the effectiveness of systemic therapies for mCRC; here we report on the association of CEA and CA19-9 changes while on treatment with clinical outcomes in pts from the SLI. Methods: Pts in the SLI received the triplet of ENCO 300 mg QD + BINI 45 mg BID + CETUX 400 mg/m2 (initial dose) then 250 mg/m2 QW in 28-day cycles. Pts were evaluated for safety, radiographic response, and change in tumor markers CEA and CA19-9. Results: 30 pts were treated. The triplet was generally well tolerated, and adverse events were consistent with known BRAF, MEK, and EGFR inhibitor toxicities. The rate of severe skin toxicities (grade 3/4) was lower than generally observed for CETUX in mCRC. Of the 29 pts with a BRAFV600E mutation, the median time on study treatment was 5.6 mo (range, 1.0–9.3 mo), and 22 (76%) remained on study treatment at the time of data cutoff. The confirmed overall response rate (ORR) was 41%, with 1 complete and 11 partial responses. In addition, 9 pts had prolonged stable disease (SD) up to 9.3 mo.CEA and CA19-9 were analyzed in 28 pts. CEA and CA19-9 decreased in 96% and 82% of these pts, respectively. Among 15 pts with treatment duration ≥5.6 mo, median/mean % decreases were 97%/79% for CEA and 92%/82% for CA19-9 in confirmed responders (n=6). Respective decreases in pts with prolonged SD (n=9) were similar: 84%/68% for CEA and 89%/68% for CA19-9. Updated safety, efficacy, and tumor marker results will be provided. Conclusions: ENCO + BINI + CETUX is generally well tolerated and has encouraging clinical activity in BRAFV 600E mCRC, with a confirmed ORR of 41%. In pts with study treatment duration ≥5.6 mo, the tumor markers CEA and CA19-9 decreased markedly and to the same degree in responders vs pts with prolonged SD, providing additional evidence of the meaningful clinical activity of this regimen. Clinical trial information: NCT02928224.

TPS3622 Background: BRAF mutations are found in ≈10% of mCRC cases. Pts with BRAFV600E mCRC have a poor prognosis, with shorter progression-free survival (PFS) and overall survival (OS) than pts with BRAFwt mCRC (Van Cutsem et al 2011; Modest et al 2012; Sorbye et al 2015). The benefits of combined BRAF + EGFR inhibition in mCRC have been demonstrated in vitro (Corcoran et al 2012; Prahallad et al 2012; Yang et al 2012), and preclinical evidence suggests that adding MEK signaling inhibition improves antitumor activity. Early clinical data indicate that BRAF + EGFR + MEK inhibition has greater activity than BRAF + EGFR inhibition in pts with BRAFV600E mCRC (Van Cutsem et al 2016). Our study will examine the combination of BINI (a MEK inhibitor) + ENCO (a selective BRAF kinase inhibitor) + CTX (an anti-EGFR antibody) and of ENCO + CTX in pts with BRAFV600E mCRC. Methods: BEACON CRC (NCT02928224) is enrolling pts with BRAFV600E mCRC whose disease has progressed after 1 or 2 prior regimens in the metastatic setting. A safety lead-in phase (≈30 pts) will determine the safety and tolerability of oral ENCO 300 mg QD + oral BINI 45 mg BID + intravenous CTX 400 mg/m2 followed by 250 mg/m2 QW. In the phase 3 portion, ≈615 pts will be randomized 1:1:1 to triplet (ENCO + BINI + CTX), doublet (ENCO + CTX), or control (investigator’s choice of IRI/CTX or FOLFIRI/CTX) arms. Pts will be treated in 28-day cycles until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, or death. The primary endpoint is OS (triplet vs control). Secondary endpoints include OS (doublet vs control), confirmed investigator-assessed objective response rate according to RECIST version 1.1 (triplet or doublet vs control; triplet vs doublet), PFS (triplet or doublet vs control), duration of response, time to response, pharmacokinetics, and pt-reported outcomes. Safety will be summarized using standard adverse event reporting. Clinical trial information: NCT02928224.

Breast cancer patients with cardiac disease are usually excluded from clinical trials of high-dose chemotherapy. We treated 52 patients with inflammatory and/or metastatic disease with sequential high-dose melphalan and stem cell rescue followed by high-dose thiotepa and stem cell rescue. Stem cells were mobilized with cyclophosphamide and/or paclitaxel and filgrastim. Left ventricular ejection fraction (LVEF) was measured by equilibrium radionuclide angiocardiography (ERNA) at baseline, after each course of chemotherapy and 4 weeks after completing both transplants. The mean absolute decrease in LVEF after the two transplants was 3.6% (P = 0.008 for the comparison with baseline LVEF), and most of this drop (−2.5%, P = 0.007) occurred after mobilization. Unexpectedly, paclitaxel was associated with a mean absolute decrease in LVEF of 3.4% (P = 0.032, n = 19), cyclophosphamide alone was not associated with a significant change in LVEF (−1.3%, P = 0.23), but mobilization with sequential paclitaxel and cyclophosphamide resulted in a mean absolute drop of 4.9% in LVEF (P = 0.009). Twelve patients were found to have a reduced LVEF (

Treatment options are limited for patients with imatinib-resistant or -intolerant accelerated phase chronic myeloid leukemia (CML-AP). Dasatinib is a novel, potent, oral, multitargeted kinase inhibitor of BCR-ABL and SRC-family kinases that showed marked efficacy in a phase 1 trial of patients with imatinib-resistant CML. Results are presented for 107 patients with CML-AP with imatinib-resistance or -intolerance from a phase 2, open-label study further evaluating dasatinib efficacy and safety. At 8 months' minimum follow-up, 81%, 64%, and 39% of patients achieved overall, major (MaHR), and complete hematologic responses, respectively, whereas 33% and 24% attained major and complete cytogenetic remission. Of 69 patients who achieved MaHR, 7 progressed. Seventy-six percent of patients are estimated to be alive and progression-free at 10 months. Response rates for the 60% of patients with baseline BCR-ABL mutations did not differ from the total population. Dasatinib was well tolerated: most nonhematologic adverse events (AEs) were mild to moderate; no imatinib-intolerant patients discontinued dasatinib because of AEs. Although common (76% of patients with severe neutropenia), cytopenias were manageable through dose modification. In summary, dasatinib induced significant hematologic and cytogenetic responses in patients with imatinib resistance or intolerance, was well tolerated, and may represent a potent new therapeutic option for CML-AP. Further follow-up is warranted. This trial was registered at www.clinicaltrials.gov as #CA180005.

2590 Background: Inhibition of phosphatidylinositol-3-kinase (PI3K)-mediated signaling may overcome resistance to different classes of chemotherapies as well as epidermal growth factor receptor (EG...

Purpose: Preclinical studies show that BMS-188797 has a broad spectrum of antitumor activity in in vitro cytotoxicity assays and tumor xenograft models. We did a phase I trial designed to determine the maximum tolerated dose and the pharmacokinetics of BMS-188797 when administered i.v. Materials and Methods: BMS-188797 was administered i.v. over 60 minutes once every 21 days to 51 patients. The initial dose cohort of 3.75 mg/m2 was set at approximately one third the lethal dose in dogs. Doses were subsequently escalated in cohorts according to a modified Fibonacci design. Results: Fifty-one patients received a total of 160 cycles of therapy. The dose-limiting toxicity of febrile neutropenia occurred in two patients at the 200 mg/m2 cohort. Moderate to severe sensory neuropathy occurred in 12 patients (24%). Four radiographic partial responses based on the Response Evaluation Criteria in Solid Tumors occurred: two in subjects with breast cancer, one in a subject with non–small cell lung cancer, and one in a subject with renal cell carcinoma. The duration of the partial responses observed were 24.1 months (renal cell carcinoma), 5.7 and 4.3 months (breast cancer), and 4.5 months (non–small cell lung cancer). Pharmacokinetics appear linear at doses through 110 mg/m2 but not at higher doses. Conclusion: The dose-limiting toxicity in this single-agent study of BMS-188797 was febrile neutropenia. The recommended phase II dose of BMS-188797 as a single agent is 175 mg/m2 i.v. for 1 hour administered every 3 weeks.

TPS3649 Background: The combination of cetuximab plus irinotecan is considered a standard of care regimen for third-line treatment of patients with wild-type KRAS metastatic colorectal cancer (mCRC...

TPS3657 Background: Despite recent advances in cytotoxic chemotherapies and targeted agents, metastatic colorectal cancer (mCRC) continues to be an area of great unmet medical need. Patients with m...

Cardiac toxicity is frequently the indication for discontinuation of an anthracycline in patients with tumors which remain anthracycline-sensitive. During the 1990s, the most frequently used second-line agents at the Yale Cancer Center (YCC) were the taxanes. The goal of this retrospective analysis was to determine the effect of paclitaxel on cardiac function in patients with cardiomyopathy. YCC outpatient clinic pharmacy order forms were used to identify all patients who had received paclitaxel between December 1995 and November 1997. The clinic records of those patients with a left ventricular ejection fraction (LVEF) of < or = 50% were reviewed to determine the temporal relation between the decreased LVEF and paclitaxel therapy. In addition, clinic records were examined for evidence of prior doxorubicin therapy and history of prior cardiac disease. Between December 1995 and November 1997, 225 patients were treated with paclitaxel in the YCC outpatient clinic. Nine patients had LVEF < or = 50% (mean 37%) prior to initiation of paclitaxel therapy. Six of these patients had equilibrium radionuclide angiocardiographic (ERNA) scans following completion of paclitaxel. In these 6 patients, the mean change in LVEF was +6% (range -3% to +29%). Four patients had improved LVEF following paclitaxel (mean 11%, range 2% to 29%), while 2 patients experienced a decrease in LVEF following paclitaxel treatment (mean 2.5%). The 3 patients who did not have ERNA scans following paclitaxel therapy had no clinical evidence of congestive heart failure. Our experience confirms the results of prior studies that paclitaxel can be safely administered in patients with underlying cardiac dysfunction.

Hepatocellular carcinoma (HCC) is the sixth most common cancer worldwide and its incidence continues to increase. Although there are approved therapies for HCC, the prognosis remains poor. The 5-year survival rate is < 5%. Nucleic acid-based therapeutics such as RNAi may improve patient outcome. Nevertheless, target identification/validation for HCC and delivery of siRNA are major challenges facing the development of HCC-specific RNAi based therapeutics. To enable target validation in vivo using RNAi, we have developed nanolipid siRNA formulations for the in vivo delivery of siRNA to orthotopic tumors. PK/PD studies in model systems demonstrate that up to 80% knockdown of target protein is achievable within tumors and that significant knockdown persists for at least 10 days following a single dose of formulated siRNA. Efficacy studies using similar formulations of siRNAs against potential HCC tumor targets, including mTOR, will be presented. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1646. doi:10.1158/1538-7445.AM2011-1646

2524 Background: CVX-060 is a recombinant humanized monoclonal antibody fused to two angiopoietin-2 (Ang2) binding peptides. In preclinical studies, CVX-060 is antiangiogenic and decreases tumor proliferation. Methods: In stage 1, pts with solid tumors received escalating doses of CVX-060 in cohorts of 3-6 pts at the following doses: 0.3, 1, 3, 6, 12, or 15 mg/kg. An additional 13 pts were treated at the 15 mg/kg dose in stage 2. CVX-060 was given once weekly in 4 week cycles as a 90 min IV infusion, decreased to 30 min as tolerated. DLTs were defined as ≥ Gr 3 AEs unrelated to tumor progression in cycle 1. Serum PK was assessed by ELISA. DCE-MRI were conducted pre- dose, Day 4, and Day 28, in pts at 3 mg/kg and higher. Results: Complete data are available on 30 of 34 pts who were enrolled in the study. Among the 30 pts (19F/11M), the median age was 65 years (21-90), ECOG performance status 0-1. Drug exposure in pts ranged from 6-407 days (median 49 days). One pt in the 0.3 mg/kg cohort experienced a DLT ...

Pts with CML-LB or CML-MB have a poor prognosis with survival from onset of blast crisis of 3–6 months. Dasatinib (SPRYCEL®, formerly BMS-354825) is a multi-targeted kinase inhibitor of BCR-ABL and SRC, which results in complete hematologic and cytogenetic responses in pts with CML-LB or CML-MB who are Im-i, or who have disease that is Im-r. Between January and June 2005, 48 CML-LB pts were enrolled in the START-L trial, and 109 CML-MB pts in the START-B trial both of which were open label, multi-center, global phase II studies. As previously reported, with a minimum of 6-months follow up in the combined blast-phase pts, the major hematologic response (MHR) rate was 32% including 26% complete hematologic responses (CHR) and the major cytogenic response (MCyR) rate was 38%, including 31% complete cytogenetic responses (CCyR). The median duration of MHR had not been reached and the median progression-free survival (PFS) was 4.3 months (mo). In both studies, dasatinib was given orally, 70 mg twice daily (BID) with escalation to 100 mg BID for poor response or reductions to 50 mg and 40 mg BID for toxicity. Pts had weekly blood counts and monthly bone marrow exams, including cytogenetics. Mutation analysis was conducted at baseline and at end of study. Quantitative PCR was carried out at pretreatment and at the time of CCyR. Overall, among all blast-crisis pts in both studies, 90% were Im-r. Due to the small number of Im-i pts, data for all pts is presented. Among the 157 pts, 56% were male, with a median age of 54 years (range 17–81). The median time from diagnosis of CML was 45 mo (range 2–216). Prior therapy included Im >600 mg/d in 50%, with Im for >3 years in 36% and stem cell transplantation in 19% of the pts. At baseline, 57% of pts had WBC

Background: Dasatanib (SPRYCEL®, formerly BMS-354825) is a potent inhibitor of BCR-ABL and SRC kinases with significant clinical activity in pts. with CML or Ph(+)ALL who have failed IM. The association between patient characteristics and pretreatment disease features and subsequent response to dasatinib has not been established. Patients and Methods: We evaluated the response of 34 consecutive pts. with Ph(+)ALL (n=30) or LyBP (n=4) who were enrolled at our center in two multicenter phase II studies of dasatinib in pts with Ph(+) lymphoid leukemias resistant to or intolerant of IM (CA180-015 and CA180-035). Dasatinib was given orally, at a starting dose of 70mg twice a day. Bone marrow (BM) was examined after 2 weeks and then monthly and included cytology, cytogenetics, quantitative PCR and BCR-ABL mutation analysis. Hematologic responses had to be maintained for at least 4 weeks. Thirty-two pts. (94%) were IM-resistant, 14 (41%) had undergone prior SCT, and 6 (18%) had failed prior therapy with nilotinib. Of 26 pts. evaluable at baseline, 18 had a complex karyotype in conjunction with either a single (n=12) or a double (n=6) Ph chromosome. BCR-ABL tyrosine kinase domain (TKD) mutations at baseline were observed in 17 of 29 eval. pts. (59%), 5 (17%) with T315I and 9 (31%) with p-loop mutations. Results: Dasatinib induced a major hematologic response (MHR) in 48% of pts. (38% complete hematologic responses (CHR), 10% no evidence of leukemia: 2nd relapse versus 1st relapse, BM blasts >80% or percentage of PB blasts. Clearance of PB blasts by day 7 was associated with an 82% MHR rate, no MHR was noted in pts. in whom PB blasts persisted after 14 days. BCR-ABL negativity by RT-PCR was achieved by 6 patients (18%) and was observed exclusively in patients who had undergone prior SCT. Thus, remission quality appears to be superior in pts with prior SCT, despite similar hematologic response rates. In addition, molecular responses were sustained only in the subgroup of patients (n=5) with wild-type BCR-ABL at study entry. Estimated median time to progression was 85 d in MHR pts. who remained PCR pos. and was not reached in the PCR neg. group. Severe adverse events (Grades 3+4) included pleural effusion (14,7%), thrombocytopenia (8,8%), neutropenic fever (8,8%), pulmonary hypertension with cor pulmonale (5,8%), gastrointestinal hemorrhage (5.8%), subdural hematomas (5.8%) and diarrhea (5,8%), indicating the need for close patient monitoring in this advanced disease population. Conclusion: Dasatinib has significant activity in Ph(+)ALL pts who have failed prior therapy including IM. In this single-center experience of 34 pts, sustained molecular responses were observed only in the 5 pts previously transplanted who had no evidence of TKD mutations at the start of dasatinib treatment, suggesting that additional immunologic and non-mutational resistance mechanisms play an important role in determining the long-term response in pts with Ph(+)ALL.

Dasatinib (SPRYCEL®, formerly BMS-354825) is a novel, oral, multi-targeted kinase inhibitor of BCR-ABL and SRC. Relapsing pts with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph(+) ALL) who have been previously treated with chemotherapy including im have a very poor prognosis. START-L is an open label, multi-center, global phase-II study, which treated 46 im-r or im-i pts with Ph(+) ALL from January through June 2005. Dasatinib was given orally, 70 mg twice daily (BID) with escalation to 100 mg BID for poor response or reductions to 50 mg and 40 mg BID for toxicity. Response was assessed on weekly blood counts and monthly bone marrow exams, including cytogenetics. Mutation analysis was conducted at baseline and at end of study. Quantitative PCR was carried out pretreatment and at the time of complete cytogenetic response (CCyR). At the time of this update, all 46 pts had a minimum of 9 months (mo) of follow-up. Of these, 44 (96%) were im-r; due to the small number of im-i pts, data for all pts are presented. 59% of patients were male and median age was 48 years. The median time from initial Ph(+) ALL diagnosis to first dose was 18 mo. All patients had been pretreated with im including 46% with 600 mg per day or more, and 52% whose duration of im treatment was more than 12 mo. 37% of the pts had received a stem cell transplant. At baseline, 67% of pts had WBC

Dasatinib (SPRYCEL®, formerly BMS-354825) is a novel, oral, multi-targeted kinase inhibitor that induces complete hematologic and cytogenetic remissions in pts in all phases of im-r or im-i CML. START-A is an open-label study of dasatinib in pts with im-r or im-i AP-CML. Preliminary results with early follow-up suggested significant activity. The present report updates the results of this study with a minimum of 9 months of follow-up. Dasatinib was given orally at 70 mg twice daily (BID). Dose escalation to 100 mg BID was allowed for inadequate initial response and reduction to 50 or 40 mg BID for persistent toxicity. Evaluation included weekly blood counts and monthly bone marrow including cytogenetics. Molecular evaluation of BCR-ABL transcript levels by real-time qPCR was performed at baseline and upon documentation of complete cytogenetic response. A total of 174 pts (161 im-r and 13 im-i) were enrolled between December 2004 and July 2005 in 39 centers worldwide. There were 96 (55%) males; median age was 57 years (range 22–86); median time from original diagnosis of CML was 82 months. Prior therapy included im in all pts (>600 mg/day in 91 (52%), im for >3 years in 103 (59%) pts, interferon in 126 (72%) pts, stem cell transplantation in 23 (13%) pts. Major cytogenetic response (MCyR) to prior im had been seen in 57 (33%) pts. The average daily dose (median across all pts) was 130 mg/day (range 44–199). Major hematologic response (MaHR) was documented in 110 (63%) pts with complete hematologic response in 75 (43%) and no evidence of leukemia in 35 (20%). At 9 months, 85% of pts have maintained their MaHR. MCyR was documented in 65 (37%) pts, complete in 49 (28%), partial in 16 (9%). Median progression-free survival (PFS) has not been reached; estimated PFS at 9 months is 70%. In the 94 pts with BCR-ABL mutations at baseline the MaHR rate was 69%. Generally, response rates were similar in the im-i and im-r groups. Cytopenias were significant with grade 3–4 thrombocytopenia and neutropenia in 82% and 76% of pts, respectively. Non-hematologic toxicities were generally mild to moderate. The most frequent (% any grade, % grade 3–4) were diarrhea (51%, 8%), headache (29%, 1%), fatigue (26%, 4%), fever (25%, 3%) and pleural effusion (25%, 3%). Pleural effusions were optimally managed with dose interruption and diuretics and/or pulse steroids. Dasatinib is highly effective in pts with im-r or im-i AP-CML with high rates of durable MaHR and MCyR. An updated analysis with at least 12 months of follow-up, including molecular response data and mutational analysis at time of progression, will be presented.

6528 Background: Dasatinib (D) (BMS-354825) is a multi-targeted kinase inhibitor of BCR-ABL and SRC. Preliminary data from a phase I study suggest high efficacy of D in IM pretreated pts. Methods: START L is an open label phase II study of D in IM-R or IM-I pts with LB-CML and Ph+ALL conducted at 42 centers worldwide. D was given orally, 70 mg twice a day (bid), with escalation to 100 mg bid for poor response or reductions to 50 mg and 40 mg bid for toxicity. Pts had weekly blood counts and monthly bone marrow exams, including cytogenetics. The primary endpoint was confirmed (sustained for at least 4 weeks) major hematologic response (MaHR) rates. Results: From January to June 2005, 101 pts were accrued. Data are available on the first 78 treated pts (42 LB-CML, 36 Ph+ALL). Of the 42 LB-CML pts, 37 were IM-R, 52% were male with median (med) age of 47 years. Prior therapy included IM >600 mg/day in 52% and stem-cell transplant (SCT) in 33% of pts. Med baseline platelet (plt) count was 32.5/nl, med BM blasts were 82%, Bcr-Abl mutations were seen in 48%, and extramedullary disease (EMD) was seen in 29% of pts. The D dose was reduced in 14%, temporarily interrupted in 33%, and escalated in 26% of pts. At 6-months, the MaHR rate was 31% including 26% complete hematologic response (CHR), the MCyR rate was 50%, and 17% of pts remained on study. Of the 36 Ph+ALL pts, 34 were IM-R, 64% were male with med age 46 years. Prior therapy included IM> 600 mg/day in 47% and SCT in 42% of pts. Baseline plt count was 53.5/nl, med BM blasts were 69%, Bcr-Abl mutations were seen in 47% and EMD was seen in 31% of pts. The D dose was reduced in 28%, temporarily interrupted in 39%, and escalated in 47% of the pts. At 6-months, the MaHR rate was 42% including 31% CHR, the MCyR rate was 58%, and 33% pts remained on study. Among all 78 pts, grade 3–4 thrombocytopenia and neutropenia was seen in 82% and 76% of pts, respectively. The most frequent D-related non-hematologic toxicities were diarrhea (30%), nausea (23%), fatigue (19%), rash (17%) and pleural effusion (13%). Conclusions: D is active in IM pretreated LB-CML and Ph+ALL pts. Data on all 101 pts will be presented at the meeting. [Table: see text]

8559 Background: Carboplatin and irinotecan have been shown to be active in pediatric tumors. Methods: The primary objective of this non-comparative, randomized study is to estimate the response rate of carboplatin AUC 4 mg/ml*min every 21 days in combination with irinotecan 12 mg/m2/day daily × 10 days every 21 days, with growth factor support (Arm A), and irinotecan 20 mg/m2/day daily × 10 days every 21 days(Arm B) in children with refractory solid tumors. The Arm A dose and schedule were determined by a prior phase I study (2003 AACR abst. #3567). One hundred and fifty-one patients were randomized and stratified by site of the primary tumor (non-CNS or CNS) and 148 were treated- 46 non-CNS and 28 CNS on Arm A, and 47 non-CNS and 27 CNS on Arm B. Non-CNS tumor types included osteosarcoma 19 (20%), rhabdomyosarcoma (RMS) 16 (17%), neuroblastoma 15 (16%), Wilm's tumor 12 (13%), sarcomas 9 (10%), retinoblastoma 5 (5%), Ewing's sarcoma 3 (3%), and others 15 (16%). CNS tumor types included gliomas (all grade...

Experimental data presented in this study indicate that prolonged pressure exerted on the kidneys of rabbits may lead to true erythrocytosis. With approximately 60 per cent of rabbits developing erythrocytosis, the pressure of experimentally induced unilateral hydronephrosis appears to be most effective in this respect. It is suggested that of the role of the renal medulla in the production of erythrocytosis is an important one. Interference with renal arteries and veins did not result in erythrocytosis. The role of erythropoietin and the possible mechanisms by which "renal pressure erythrocytosis" is produced is discussed.