Phase 1 trial of dasatinib combined with afatinib for epidermal growth factor receptor- (EGFR-) mutated lung cancer with acquired tyrosine kinase inhibitor (TKI) resistance

BACKGROUND

Bypass activation of Src family kinases can confer resistance to EGFR tyrosine kinase inhibitors (TKIs) based on preclinical models. We prospectively assessed the safety and clinical activity of dasatinib and afatinib in combination for patients with resistant EGFR-mutant lung cancer.

METHODS

An open-label, dose-escalation phase 1/2 trial (NCT01999985) with 2-stage expansion was conducted with 25 lung cancer patients. Dose expansion required activating EGFR mutations and progression following prior EGFR TKI.

RESULTS

Patients were 72% Caucasian and received median of 2 prior lines of therapy. Maximum-tolerated dose was 30 mg afatinib with 100 mg dasatinib. New or increased pleural effusions were observed in 56% of patients. No radiologic responses were observed, although several EGFR-mutant TKI-resistant patients (26%) had prolonged stable disease over 6 months. The combination reduced the EGFR mutation and T790M variant allele frequency in cell-free DNA (p < .05). Nonetheless, the threshold for futility was met, based on 6-month progression-free survival. For EGFR TKI-resistant patients, median progression-free survival was 3.7 months (95% confidence interval (CI), 2.3-5.0) and overall survival was 14.7 months (95% CI, 8.5-20.9).

CONCLUSIONS

The combination had a manageable toxicity profile and in vivo T790M modulation, but no objective clinical responses were observed.

Tyrosine kinase inhibitor interruptions, discontinuations and switching in patients with chronic-phase chronic myeloid leukemia in routine clinical practice: SIMPLICITY

SIMPLICITY (NCT01244750) is an observational study exploring tyrosine kinase inhibitor (TKI) use and management patterns in patients with chronic phase-chronic myeloid leukemia in the US and Europe in routine clinical practice. Herein we describe interruptions, discontinuations and switching of TKI therapy during the initial 2 years of treatment among 1121 patients prospectively enrolled between October 1, 2010 and March 7, 2017. Patient characteristics were broadly similar between the imatinib (n = 370), dasatinib (n = 376), and nilotinib (n = 375) cohorts. Treatment interruptions occurred in 16.4% (year 1) and 4.0% (year 2) of patients, mainly attributed to hematologic intolerances. Treatment discontinuations occurred in 21.8% (year 1) and 10.2% (year 2) of patients, with the highest rate within the first 3 months for intolerance. Switching of TKI was seen in 17.8% (year 1) and 9.5% (year 2) of patients. Significant associations were found between TKI switching and female gender (year 1), age ≥65 years at diagnosis (year 2) and treatment with imatinib (year 2). Intolerance was the most common reason given for patients discontinuing and for switching TKI therapy; however resistance was also cited. Lack of response monitoring in routine clinical practice may have resulted in lower identification of resistance in this dataset. Data from SIMPLICITY suggest that, in routine clinical practice, intolerance and resistance to TKIs influence decisions to change treatment. Changes in TKI therapy are frequent, with nearly a third of patients discontinuing their first-line TKI.

Burden of Infections Among Chronic Myeloid Leukemia Patients Receiving Dasatinib or Nilotinib: A Real-World Retrospective Healthcare Claims Study in the United States

INTRODUCTION

Tyrosine kinase inhibitors (TKI) have been demonstrated to prolong survival in patients with chronic myeloid leukemia (CML). However, TKIs may be associated with an increased risk of infections. This study compared healthcare resource utilization (HRU) and costs among patients with CML receiving dasatinib or nilotinib, with a focus on infection-related economic outcomes.

METHODS

Two large administrative databases were used to identify adult patients newly diagnosed with CML who initiated dasatinib or nilotinib as first- (1L) or second-line (2L) therapy and were classified into the following 1L (dasatinib 1L/nilotinib 1L cohorts) or 2L (dasatinib 2L/nilotinib 2L) cohorts based on the initiated 1L/2L TKI therapy. Infection-related HRU and healthcare costs were compared between cohorts, separately for 1L and 2L.

RESULTS

Cohorts included 1156 patients in the dasatinib 1L and 677 patients in the nilotinib 1L cohorts, 322 patients in the dasatinib 2L, and 207 in the nilotinib 2L cohorts. In 1L and 2L, infection-related HRU was higher for dasatinib than nilotinib cohorts. Infection-related inpatient (IP) days constituted a larger proportion of all-cause IP days in the 1L/2L dasatinib than 1L/2L nilotinib cohorts (dasatinib 1L/2L: 53%/58%; nilotinib 1L/2L: 50%/46%). Compared to the nilotinib cohort, the dasatinib cohort had higher all-cause total costs per patient per year by US$17,901 in 1L and $28,625 in 2L. Of the total cost difference, infection-related were $6048 (34%) in 1L and $28,192 (99%) in 2L, largely driven by IP cost differences (1L/2L: 96%/98%).

CONCLUSIONS

Dasatinib was associated with higher HRU and healthcare costs compared to nilotinib, particularly related to infections.

FUNDING

Novartis Pharmaceutical Corporation.

Dasatinib monotherapy for newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukemia with pulmonary infection in induction remission: A case report and review of the literature

RATIONALE

There is currently no clinical standard for induction therapy in the treatment of Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph ALL). Chemotherapy in combination with tyrosine kinase inhibitors (TKIs) recognized as the first line of therapy to induce remission in Ph ALL patients; however, both the infectious and non-infectious toxicities remain high and lead to early excessive treatment-related mortality (TRM). Single-agent TKI "monotherapy" may reduce toxicity and TRM; however, TKI induction monotherapy and its effectiveness in the induction of remission in newly diagnosed Ph ALL has yet to be investigated.

PATIENT CONCERNS

A 59-year-old man who was newly diagnosed Ph ALL with 93% blast cells and a t (9, 22) karyotype. But the patient also suffered from pulmonary infection, including fever and dyspnea.

DIAGNOSES

The patient was newly diagnosed with Ph ALL with pulmonary infection.

INTERVENTIONS

The patient received oral dasatinib monotherapy (100 mg qd) for 28 days as induction therapy.

OUTCOMES

The patient reached complete remission with negative minimal residual disease detected by real-time quantitative polymerase chain reaction after induction therapy for 28 days.

LESSONS

This is the first report on the use of dasatinib monotherapy in the absence of other drugs, such as steroids, for induction therapy in a newly diagnosed Ph ALL patient with pulmonary infection.

Dasatinib dose management for the treatment of chronic myeloid leukemia

Chronic myeloid leukemia (CML) has evolved into a chronic disease that is managed with tyrosine kinase inhibitor therapy. Now that long-term survival has been achieved in patients with CML, the focus of treatment has shifted to dose optimization, with the goal of maintaining response while improving quality of life. In this review, the authors discuss optimizing the dose of the second-generation tyrosine kinase inhibitor dasatinib. Once-daily dosing regimens for dasatinib in the first and later lines of treatment were established through long-term (5-year and 7-year) trials. Recently published data have indicated that further dose optimization may maintain efficacy while minimizing adverse events. Results obtained from dose optimization and discontinuation trials currently in progress will help practitioners determine the best dose and duration of dasatinib for patients with CML, because treatment decisions will be made through continued discussions between physicians and patients. Cancer 2018;124:1660-72. © 2018 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Incidence of type 2 diabetes mellitus and hyperlipidemia in patients prescribed dasatinib or nilotinib as first- or second-line therapy for chronic myelogenous leukemia in the US

OBJECTIVE

Evaluate the incidence of type 2 diabetes mellitus (T2DM) and hyperlipidemia (HLD) in CML patients initiating therapy with dasatinib or nilotinib.

METHODS

Retrospective study using MarketScan claims from January 2006 to December 2014. The first analysis evaluated occurrence of T2DM, defined as ≥2 claims with a T2DM ICD-9 code or 1 diagnosis claim and an antidiabetic medication. The second analysis evaluated occurrence of HLD, defined as ≥2 claims with an HLD ICD-9 code, or 1 diagnosis claim and an anti-HLD medication. Incidence rates were computed as number of events divided by sum of person years (PY) at risk for all subjects. Multivariate Cox proportional hazards models estimated hazard ratios (HRs) for T2DM or HLD.

RESULTS

There were 2004 and 1280 patients who met the criteria for the T2DM analysis (n = 1272 dasatinib, n = 732 nilotinib) and HLD analysis (n = 845 dasatinib, n = 435 nilotinib). The incidence rate of T2DM was 40.4 per 1000 PY (95% CI: 27.60, 56.98) for nilotinib and 17.6 per 1000 PY (95% CI: 11.14, 26.38) for dasatinib. HR for occurrence of T2DM was 2.77 (95% CI: 1.58, 4.86), indicating that patients on nilotinib had a significantly higher adjusted risk for incident T2DM. The incidence rate of HLD was 74.6 per 1000 PY (95% CI: 50.70, 105.94) for nilotinib and 46.4 per 1000 PY (95% CI: 33.00, 63.45) for dasatinib. HR for occurrence of HLD was 1.75 (95% CI: 1.07, 2.87) indicating that patients on nilotinib had a significantly higher adjusted risk for incident HLD.

CONCLUSIONS

Patients receiving nilotinib had significantly higher rates of incident T2DM or HLD than patients on dasatinib.

Dasatinib cessation after deep molecular response exceeding 2 years and natural killer cell transition during dasatinib consolidation

Tyrosine kinase inhibitors (TKI) improve the prognosis of patients with chronic myelogenous leukemia (CML) by inducing substantial deep molecular responses (DMR); some patients have successfully discontinued TKI therapy after maintaining DMR for ≥1 year. In this cessation study, we investigated the optimal conditions for dasatinib discontinuation in patients who maintained DMR for ≥2 years. This study included 54 patients with CML who were enrolled in a D‐STOP multicenter prospective trial, had achieved DMR, and had discontinued dasatinib after 2‐year consolidation. Peripheral lymphocyte profiles were analyzed by flow cytometry. The estimated 12‐month treatment‐free survival (TFS) was 62.9% (95% confidence interval: 48.5%‐74.2%). During dasatinib consolidation, the percentage of total lymphocytes and numbers of CD3⁻ CD56⁺ natural killer (NK) cells, CD16⁺ CD56⁺ NK cells and CD56⁺ CD57⁺ NK‐large granular lymphocytes (LGL) were significantly higher in patients with molecular relapse after discontinuation but remained unchanged in patients without molecular relapse for >7 months. At the end of consolidation, patients whose total lymphocytes comprised <41% CD3⁻ CD56⁺ NK cells, <35% CD16⁺ CD56⁺ NK cells, or <27% CD56⁺ CD57⁺ NK‐LGL cells had higher TFS relative to other patients (77% vs 18%; P < .0008; 76% vs 10%; P < .0001; 84% vs 46%; P = .0059, respectively). The increase in the number of these NK cells occurred only during dasatinib consolidation. In patients with DMR, dasatinib discontinuation after 2‐year consolidation can lead to high TFS. This outcome depends significantly on a smaller increase in NK cells during dasatinib consolidation.

Novel lung imaging biomarkers and skin gene expression subsetting in dasatinib treatment of systemic sclerosis-associated interstitial lung disease

Background

There are no effective treatments or validated clinical response markers in systemic sclerosis (SSc). We assessed imaging biomarkers and performed gene expression profiling in a single-arm open-label clinical trial of tyrosine kinase inhibitor dasatinib in patients with SSc-associated interstitial lung disease (SSc-ILD).

Methods

Primary objectives were safety and pharmacokinetics. Secondary outcomes included clinical assessments, quantitative high-resolution computed tomography (HRCT) of the chest, serum biomarker assays and skin biopsy-based gene expression subset assignments. Clinical response was defined as decrease of >5 or >20% from baseline in the modified Rodnan Skin Score (MRSS). Pulmonary function was assessed at baseline and day 169.

Results

Dasatinib was well-tolerated in 31 patients receiving drug for a median of nine months. No significant changes in clinical assessments or serum biomarkers were seen at six months. By quantitative HRCT, 65% of patients showed no progression of lung fibrosis, and 39% showed no progression of total ILD. Among 12 subjects with available baseline and post-treatment skin biopsies, three were improvers and nine were non-improvers. Improvers mapped to the fibroproliferative or normal-like subsets, while seven out of nine non-improvers were in the inflammatory subset (p = 0.0455). Improvers showed stability in forced vital capacity (FVC) and diffusing capacity for carbon monoxide (D_LCO), while both measures showed a decline in non-improvers (p = 0.1289 and p = 0.0195, respectively). Inflammatory gene expression subset was associated with higher baseline HRCT score (p = 0.0556). Non-improvers showed significant increase in lung fibrosis (p = 0.0313).

Conclusions

In patients with SSc-ILD dasatinib treatment was associated with acceptable safety profile but no significant clinical efficacy. Patients in the inflammatory gene expression subset showed increase in skin fibrosis, decreasing pulmonary function and worsening lung fibrosis during the study. These findings suggest that target tissue-specific gene expression analyses can help match patients and therapeutic interventions in heterogeneous diseases such as SSc, and quantitative HRCT is useful for assessing clinical outcomes.

Trial registration

Clinicaltrials.gov NCT00764309

A simple reduction-sensitive micelles co-delivery of paclitaxel and dasatinib to overcome tumor multidrug resistance

Multidrug resistance (MDR) is one of the major obstacles in successful chemotherapy. The combination of chemotherapy drugs and multidrug-resistant reversing agents for treating MDR tumor is a good strategy to overcome MDR. In this work, we prepared the simple redox-responsive micelles based on mPEG-SS-C18 as a co-delivery system to load the paclitaxel (PTX) and dasatinib (DAS) for treatment of MCF-7/ADR cells. The co-loaded micelles had a good dispersity and a spherical shape with a uniform size distribution, and they could quickly disassemble and rapidly release drugs under the reduction environment. Compared with MCF-7 cells, the DAS and PTX co-loaded redox-sensitive micelle (SS-PDNPs) showed stronger cytotoxicity and a more improving intracellular drug concentration than other drug formulations in MCF-7/ADR cells. In summary, the results suggested that the simple co-delivery micelles of PTX and DAS possessed significant potential to overcome drug resistance in cancer therapy.

Circulating DNA Demonstrates Convergent Evolution and Common Resistance Mechanisms during Treatment of Colorectal Cancer

Purpose: Liquid biopsies allow the tracking of clonal dynamics and detection of mutations during treatment.Experimental Design: We evaluated under blinded conditions the ability of cell-free DNA (cfDNA) to detect RAS/BRAF mutations in the plasma of 42 metastatic colorectal cancer patients treated on a phase Ib/II trial of FOLFOX and dasatinib, with or without cetuximab.Results: Prior to treatment, sequencing of archival tissue detected mutations in 25 of 42 patients (60%), while the cfDNA assay detected mutations in 37 of 42 patients (88%). Our cfDNA assay detected mutations with allele frequencies as low as 0.01%. After exposure to treatment, 41 of 42 patients (98%) had a cfDNA-detected RAS/BRAF mutation. Of 21 patients followed with serial measurements who were RAS/BRAF mutant at baseline, 11 (52%) showed additional point mutation following treatment and 3 (14%) no longer had detectable levels of another mutant allele. Of RAS/BRAF wild-type tumors at baseline, 4 of 5 (80%) showed additional point mutations. cfDNA quantitative measurements from this study closely mirrored changes in CEA and CT scan results, highlighting the importance of obtaining quantitative data beyond the mere presence of a mutation.Conclusions: Our findings demonstrate the development of new RAS/BRAF mutations in patients regardless of whether they had preexisting mutations in the pathway, demonstrating a convergent evolutionary pattern. Clin Cancer Res; 23(16); 4578-91. ©2017 AACR.

Frontline Dasatinib Treatment in a "Real-Life" Cohort of Patients Older than 65 Years with Chronic Myeloid Leukemia

Dasatinib (DAS) has been licensed for the frontline treatment in chronic myeloid leukemia (CML). However, very few data are available regarding its efficacy and toxicity in elderly patients with CML outside clinical trials. To address this issue, we set out a “real-life” cohort of 65 chronic phase CML patients older than 65 years (median age 75.1 years) treated frontline with DAS in 26 Italian centers from June 2012 to June 2015, focusing our attention on toxicity and efficacy data. One third of patients (20/65: 30.7%) had 3 or more comorbidities and required concomitant therapies; according to Sokal classification, 3 patients (4.6%) were low risk, 39 (60.0%) intermediate risk, and 20 (30.8%) high risk, whereas 3 (4.6%) were not classifiable. DAS starting dose was 100 mg once a day in 54 patients (83.0%), whereas 11 patients (17.0%) received less than 100 mg/day. Grade 3/4 hematologic and extrahematologic toxicities were reported in 8 (12.3%) and 12 (18.5%) patients, respectively. Overall, 10 patients (15.4%) permanently discontinued DAS because of toxicities. Pleural effusions (all WHO grades) occurred in 12 patients (18.5%) and in 5 of them occurred during the first 3 months. DAS treatment induced in 60/65 patients (92.3%) a complete cytogenetic response and in 50/65 (76.9%) also a major molecular response. These findings show that DAS might play an important role in the frontline treatment of CML patients >65 years old, proving efficacy and having a favorable safety profile also in elderly subjects with comorbidities.

Doxorubicin delivered by a redox-responsive dasatinib-containing polymeric prodrug carrier for combination therapy

Two novel prodrug polymers POEG-b-PSSDas (redox-sensitive) and POEG-b-PCCDas (redox-insensitive), which consist of poly(oligo(ethylene glycol) methacrylate) (POEG) hydrophilic blocks and dasatinib (DAS, an oncogenic tyrosine kinases inhibitor) conjugated hydrophobic blocks, were designed as dual-functional carriers for codelivery with doxorubicin (DOX). Both carriers retained antitumor activity of DAS and could form mixed micelles with DOX. Compared to POEG-b-PCCDas micelles, incorporation of disulfide linkage into POEG-b-PSSDas micelles facilitated efficient cleavage of DAS from prodrug micelles in tumor cells/tissues, leading to a higher level of anti-tumor activity in vitro and in vivo. In addition, DOX-loaded POEG-b-PSSDas micelles exhibited triggered DOX release under a redox environment (10mM glutathione, GSH), and demonstrated enhanced cytotoxicity against 4T1.2 and PC3 cell lines compared to DOX and DOX-loaded POEG-b-PCCDas micelles. More importantly, DOX-loaded POEG-b-PSSDas micelles were more effective in inhibiting the tumor growth and prolonging the survival rate in an aggressive murine breast cancer model (4T1.2) compared to DOX-loaded POEG-b-PCCDas micelles and a micellar formulation co-loaded with DOX and DAS. This redox-responsive prodrug micellar system provides an attractive strategy for effective combination of tumor targeted therapy and traditional chemotherapy, which warrants further investigation.

An economic analysis of high-dose imatinib, dasatinib, and nilotinib for imatinib-resistant chronic phase chronic myeloid leukemia in China: A CHEERS-compliant article

BACKGROUND

The aim of the study was to test the cost-effectiveness of dasatinib compared to high-dose imatinib and nilotinib in Chinese patients who were diagnosed with imatinib-resistant chronic myeloid leukemia in the chronic phase (CML-CP).

METHODS

A Markov model combined with clinical effectiveness, utility, and cost data was used. The sensitivity analyses were conducted to determine the robustness of the model outcomes. The impact of patient assistance programs (PAPs) was assessed.

RESULTS

Treatment with dasatinib is expected to produce 3.65, 0.59, and 0.15 more quality-adjusted life years (QALYs) in comparison with high-dose imatinib (600 and 800 mg) and nilotinib, respectively. When a PAP was available, dasatinib yielded an incremental cost of $16,417 per QALY compared to imatinib (600 mg) and was cost-saving compared to imatinib (800 mg) and nilotinib.

CONCLUSION

When PAP is available in the Chinese setting, dasatinib is likely to be a cost-effective strategy for patients with CML-CP standard-dose imatinib resistance. The results should be carefully explained due to the assumptions and limitations used in the study.

Combined KIT and CTLA-4 Blockade in Patients with Refractory GIST and Other Advanced Sarcomas: A Phase Ib Study of Dasatinib plus Ipilimumab

Purpose: A phase Ib study of dasatinib plus ipilimumab in patients with gastrointestinal stromal tumor (GIST) and other sarcomas was performed on the basis of preclinical data demonstrating that combined KIT and CTLA-4 blockade is synergistic.Experimental Design: A standard 3 + 3 design was used to evaluate the safety, efficacy, and immune correlates of treatment. Dose escalation cohorts received ipilimumab 10 or 3 mg/kg every 3 weeks, followed by maintenance every 12 weeks with escalating doses of dasatinib (70 mg daily, 100 mg daily, or 70 mg twice daily). Response was assessed by RECIST 1.1, Choi, and immune-related RECIST criteria (irRC).Results: A total of 28 patients (17 male) were enrolled. Histologic subtypes included GISTs (n = 20) and other sarcomas (n = 8.) Dasatinib 70 mg/day with ipilimumab 10 mg/kg or dasatinib 140 mg/day with ipilimumab 3 mg/kg can be safely administered. Dose-limiting toxicities included grade 3 gastric hemorrhage and anemia. No partial or complete responses were noted by RECIST or irRC. There were 7 of 13 partial responses in the GIST patients by Choi criteria, and 3 of 13 patients each had stable and progressive disease, respectively.Conclusions: Dasatinib and ipilimumab can be safely administered to GIST and sarcoma patients. However, dasatinib was not synergistic with ipilimumab, as there was limited clinical efficacy with the combination. This limited cohort provides prospective data that indoleamine-2,3-dioxygenase (IDO) suppression may potentially correlate with antitumor efficacy in GIST. Given the small cohort, it is only hypothesis generating and additional data would be required. In the era of more modern and effective checkpoint inhibitors, next steps could be consideration of tyrosine kinase inhibitors or IDO inhibitors in combination with anti-PD-1 therapy. Clin Cancer Res; 23(12); 2972-80. ©2016 AACR.

Dasatinib synergises with irinotecan to suppress hepatocellular carcinoma via inhibiting the protein synthesis of PLK1

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common types of malignant tumour and has poor prognosis. Currently, systematic chemotherapy is the only approach to prolong survival. Thus the development of new treatment regimens is urgently needed to improve the therapeutic efficacy. Our study intended to assess the combination of dasatinib and irinotecan against HCC and made an effort to develop a potential medical choice for advanced HCC patients.

METHODS

We used SRB colorimetric assay and clonogenic assay to assess antitumour effect in vitro and HCC xenograft model to assess antitumour effect in vivo. We applied flow cytometry and western blotting to explore the mechanism of the combined therapy. Knockdown and overexpression of PLK1 are also applied for validation.

RESULTS

We confirmed that dasatinib has synergistic effect with irinotecan (or SN38) on HCC both in vitro and in vivo. The effect is due to arisen apoptosis rate of HCC cells that is accompanied by mitochondria dysfunction. The enhanced antitumour efficacy of SN38 could be explained by additional inhibition of PLK1, which is triggered by dasatinib. Unlike existed PLK1 inhibitors, dasatinib does not inhibit PLK1 activity in a direct way. Instead, we found that dasatinib reduces PLK1 level by interfering with its protein synthesis progress. We validated that this kind of downregulation of PLK1 level has a key role in the synergistic effect of the two agents.

CONCLUSIONS

Dasatinib is able to reinforce the anti-HCC efficacy of irinotecan/SN38 by downregulation of PLK1 synthesis. The combination of the two agents might be a potential medical choice for HCC therapy.

Dual Inhibition of EGFR and c-Src by Cetuximab and Dasatinib Combined with FOLFOX Chemotherapy in Patients with Metastatic Colorectal Cancer

Purpose: Aberrant activation of the intracellular tyrosine kinase Src has been implicated as a mechanism of acquired chemotherapy resistance in metastatic colorectal cancer (mCRC). Here, the oral tyrosine kinase Src inhibitor, dasatinib, was investigated in combination with FOLFOX and cetuximab.Experimental Design: We performed a phase IB/II study of 77 patients with previously treated mCRC. Primary objectives were to determine the maximum tolerated dose, dose-limiting toxicities (DLT), pharmacodynamics, and efficacy. Using a 3 + 3 design, patients received FOLFOX6 with cetuximab and escalating doses of dasatinib (100, 150, 200 mg daily), followed by a 12-patient expansion cohort at 150 mg. Phase II studies evaluated FOLFOX plus dasatinib 100 mg in KRAS c12/13^mut patients or in combination with cetuximab if KRAS c12/13^WT FAK and paxillin were utilized as surrogate blood biomarkers of Src inhibition, and paired biopsies of liver metastases were obtained in patients in the expansion cohort.Results: In phase IB, the DLTs were grade 3/4 fatigue (20%) and neutropenia (23%). In phase II, grade 3/4 fatigue (23%) and pleural effusions (11%) were present. Response rates were 20% (6 of 30) in the phase IB escalation and expansion cohort and 13% (3 of 24) and 0% (0 of 23) in the KRAS c12/13^WT and mutant cohorts of phase II, respectively. Median progression-free survival was 4.6, 2.3, and 2.3 months, respectively. There was no evidence of Src inhibition based on surrogate blood biomarkers or paired tumor biopsies.Conclusions: The combination of dasatinib plus FOLFOX with or without cetuximab showed only modest clinical activity in refractory colorectal cancer. This appears to be primarily due to a failure to fully inhibit Src at the achievable doses of dasatinib. The combination of dasatinib plus FOLFOX with or without cetuximab did not show meaningful clinical activity in refractory colorectal cancer due to failure to fully inhibit Src. Clin Cancer Res; 23(15); 4146-54. ©2017 AACR.

Response to Tyrosine Kinase Inhibitors in Myeloproliferative Neoplasia with 8p11 Translocation and CEP110-FGFR1 Rearrangement

This brief communication reports on a patient with an exceedingly rare "8p11 (eight-p-eleven) myeloproliferative syndrome" (EMS) with CEP110-FGFR1 rearrangement who responded to treatment with the multi-tyrosine kinase inhibitor (TKI) dasatinib. Dasatinib improved quality of life substantially by increasing blood counts and reducing the need for transfusions. This report demonstrates that the second-generation TKI may provide a therapeutic option for elderly and frail EMS patients who cannot be offered aggressive therapy, including allogeneic hematopoietic cell transplantation. The Oncologist 2017;22:480-483.

Phase 2 placebo-controlled, double-blind trial of dasatinib added to gemcitabine for patients with locally-advanced pancreatic cancer

Background

Pancreatic ductal adenocarcinoma (PDAC) has a high mortality rate with limited treatment options. Gemcitabine provides a marginal survival benefit for patients with advanced PDAC. Dasatinib is a competitive inhibitor of Src kinase, which is overexpressed in PDAC tumors. Dasatinib and gemcitabine were combined in a phase 1 clinical trial where stable disease was achieved in two of eight patients with gemcitabine-refractory PDAC.

Patients and methods

This placebo-controlled, randomized, double-blind, phase II study compared the combination of gemcitabine plus dasatinib to gemcitabine plus placebo in patients with locally advanced, non-metastatic PDAC. Patients received gemcitabine 1000 mg/m2 (30-min IV infusion) on days 1, 8, 15 of a 28-day cycle combined with either 100 mg oral dasatinib or placebo tablets daily. The primary objective was overall survival (OS), with safety and progression-free survival (PFS) as secondary objectives. Exploratory endpoints included overall response rate, freedom from distant metastasis, pain and fatigue progression and response rate, and CA19-9 response rate.

Results

There was no statistically significant difference in OS between the two treatment groups (HR = 1.16; 95% confidence interval [CI]: 0.81-1.65; P = 0.5656). Secondary and exploratory endpoint analyses also showed no statistically significant differences. The burden of toxicity was higher in the dasatinib arm.

Conclusions

Dasatinib failed to show increased OS or PFS in patients with locally advanced PDAC. Alternative combinations or trial designs may show a role for src inhibition in PDAC treatment.

Modelling Predictors of Molecular Response to Frontline Imatinib for Patients with Chronic Myeloid Leukaemia

BACKGROUND

Treatment of patients with chronic myeloid leukaemia (CML) has become increasingly difficult in recent years due to the variety of treatment options available and challenge deciding on the most appropriate treatment strategy for an individual patient. To facilitate the treatment strategy decision, disease assessment should involve molecular response to initial treatment for an individual patient. Patients predicted not to achieve major molecular response (MMR) at 24 months to frontline imatinib may be better treated with alternative frontline therapies, such as nilotinib or dasatinib. The aims of this study were to i) understand the clinical prediction 'rules' for predicting MMR at 24 months for CML patients treated with imatinib using clinical, molecular, and cell count observations (predictive factors collected at diagnosis and categorised based on available knowledge) and ii) develop a predictive model for CML treatment management. This predictive model was developed, based on CML patients undergoing imatinib therapy enrolled in the TIDEL II clinical trial with an experimentally identified achieving MMR group and non-achieving MMR group, by addressing the challenge as a machine learning problem. The recommended model was validated externally using an independent data set from King Faisal Specialist Hospital and Research Centre, Saudi Arabia.

PRINCIPLE FINDINGS

The common prognostic scores yielded similar sensitivity performance in testing and validation datasets and are therefore good predictors of the positive group. The G-mean and F-score values in our models outperformed the common prognostic scores in testing and validation datasets and are therefore good predictors for both the positive and negative groups. Furthermore, a high PPV above 65% indicated that our models are appropriate for making decisions at diagnosis and pre-therapy. Study limitations include that prior knowledge may change based on varying expert opinions; hence, representing the category boundaries of each predictive factor could dramatically change performance of the models.

Hyper-CVAD plus ponatinib versus hyper-CVAD plus dasatinib as frontline therapy for patients with Philadelphia chromosome-positive acute lymphoblastic leukemia: A propensity score analysis

BACKGROUND

The clinical efficacy of hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone (HCVAD) plus ponatinib has not been compared with that of HCVAD plus dasatinib in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) in a randomized clinical trial.

METHODS

The authors analyzed 110 patients with newly diagnosed Ph+ ALL who were enrolled in 2 consecutive, prospective, phase 2 clinical trials of frontline HCVAD with either dasatinib (63 patients) or ponatinib (47 patients). Propensity score analysis with 1:1 matching with the nearest neighbor matching method and inverse probability of treatment weighting (IPTW) analysis based on the propensity scores were performed to assess response rates, event-free survival (EFS), and overall survival (OS) between the cohorts.

RESULTS

Propensity score matching identified 41 patients in each cohort. With propensity score matching, the 3-year EFS rates for patients treated with HCVAD plus ponatinib and HCVAD plus dasatinib were 69% and 46%, respectively (P =.04), and the 3-year OS rates were 83% and 56%, respectively (P =.03). IPTW analysis using prematching cohorts demonstrated that patients treated with HCVAD plus ponatinib had significantly higher rates of minimal residual disease negativity by flow cytometry on day 21, complete cytogenetic response at complete response, major molecular response at complete response and at 3 months, and complete molecular response at 3 months. IPTW confirmed that treatment with HCVAD plus ponatinib was associated with longer EFS (P =.003) and OS (P =.001) compared with treatment with HCVAD plus dasatinib.

CONCLUSIONS

The clinical outcome of patients treated with HCVAD plus ponatinib appears to be superior to that of patients treated with HCVAD plus dasatinib among individuals with Ph+ ALL. Cancer 2016;122:3650-6. © 2016 American Cancer Society.

Oxidation of KCNB1 Potassium Channels Causes Neurotoxicity and Cognitive Impairment in a Mouse Model of Traumatic Brain Injury

The delayed rectifier potassium (K+) channel KCNB1 (Kv2.1), which conducts a major somatodendritic current in cortex and hippocampus, is known to undergo oxidation in the brain, but whether this can cause neurodegeneration and cognitive impairment is not known. Here, we used transgenic mice harboring human KCNB1 wild-type (Tg-WT) or a nonoxidable C73A mutant (Tg-C73A) in cortex and hippocampus to determine whether oxidized KCNB1 channels affect brain function. Animals were subjected to moderate traumatic brain injury (TBI), a condition characterized by extensive oxidative stress. Dasatinib, a Food and Drug Administration-approved inhibitor of Src tyrosine kinases, was used to impinge on the proapoptotic signaling pathway activated by oxidized KCNB1 channels. Thus, typical lesions of brain injury, namely, inflammation (astrocytosis), neurodegeneration, and cell death, were markedly reduced in Tg-C73A and dasatinib-treated non-Tg animals. Accordingly, Tg-C73A mice and non-Tg mice treated with dasatinib exhibited improved behavioral outcomes in motor (rotarod) and cognitive (Morris water maze) assays compared to controls. Moreover, the activity of Src kinases, along with oxidative stress, were significantly diminished in Tg-C73A brains. Together, these data demonstrate that oxidation of KCNB1 channels is a contributing mechanism to cellular and behavioral deficits in vertebrates and suggest a new therapeutic approach to TBI.

SIGNIFICANCE STATEMENT

This study provides the first experimental evidence that oxidation of a K+ channel constitutes a mechanism of neuronal and cognitive impairment in vertebrates. Specifically, the interaction of KCNB1 channels with reactive oxygen species plays a major role in the etiology of mouse model of traumatic brain injury (TBI), a condition associated with extensive oxidative stress. In addition, a Food and Drug Administration-approved drug ameliorates the outcome of TBI in mouse, by directly impinging on the toxic pathway activated in response to oxidation of the KCNB1 channel. These findings elucidate a basic mechanism of neurotoxicity in vertebrates and might lead to a new therapeutic approach to TBI in humans, which, despite significant efforts, is a condition that remains without effective pharmacological treatments.

Phase II studies of two different schedules of dasatinib in bone metastasis predominant metastatic breast cancer: SWOG S0622

Bone metastases from breast cancer are common, causing significant morbidity. Preclinical data of dasatinib, an oral small molecule inhibitor of multiple oncogenic tyrosine kinases, suggested efficacy in tumor control and palliation of bone metastases in metastatic breast cancer (MBC). This clinical trial aimed to determine whether treatment with either of 2 dose schedules of dasatinib results in a progression-free survival (PFS) >50 % at 24 weeks in bone metastasis predominant MBC, to evaluate the toxicity of the 2 dosing regimens, and explore whether treatment results in decreased serum bone turnover markers and patient-reported "worst pain." Subjects with bone metastasis predominant MBC were randomly assigned to either 100 mg of dasatinib once daily, or 70 mg twice daily, with treatment continued until time of disease progression or intolerable toxicity. Planned accrual was 40 patients in each arm. The primary trial endpoint was PFS, defined as time from registration to progression or death due to any cause. Median PFS for all eligible patients (79) was 12.6 weeks (95 % CI 9.1-16.7). Neither cohort met the threshold for further clinical interest. There were no significant differences in PFS by randomized treatment arm (p = 0.85). Toxicity was similar in both cohorts, with no clear trend in serum biomarkers of bone turnover or patient-reported pain. Dasatinib was ineffective in controlling bone-predominant MBC in a patient population, unselected by molecular markers. Further study of dasatinib in breast cancer should not be pursued unless performed in molecularly determined patient subsets, or rational combinations.

The Effects of Dasatinib in Experimental Acute Respiratory Distress Syndrome Depend on Dose and Etiology

BACKGROUND/AIMS

Evidence suggests that tyrosine-kinase inhibitors may attenuate lung inflammation and fibrosis in experimental acute respiratory distress syndrome (ARDS). We hypothesized that dasatinib, a tyrosine-kinase inhibitor, might act differently depending on the ARDS etiology and the dose.

METHODS

C57/BL6 mice were divided to be pre-treated with dasatinib (1mg/kg or 10mg/kg) or vehicle (1% dimethyl-sulfoxide) by oral gavage. Thirty-minutes after pre-treatment, mice were subdivided into control (C) or ARDS groups. ARDS animals received Escherichia coli lipopolysaccharide intratracheally (ARDSp) or intraperitoneally (ARDSexp). A new dose of dasatinib or vehicle was administered at 6 and 24h.

RESULTS

Forty-eight hours after ARDS induction, dasatinib 1mg/kg yielded: improved lung morphofunction and reduced cells expressing toll-like receptor (TLR)-4 in lung, independent of ARDS etiology; reduced neutrophil and levels of interleukin (IL)-6, IL-10 and transforming growth factor (TGF)-β in ARDSp. The higher dose of dasatinib caused no changes in lung mechanics, diffuse alveolar damage, neutrophil, or cells expressing TLR4, but increased IL-6, vascular endothelial growth factor (VEGF), and cells expressing Fas receptor in lung in ARDSp. In ARDSexp, it improved lung morphofunction, increased VEGF, and reduced cells expressing TLR4. Conclusion: Dasatinib may have therapeutic potential in ARDS independent of etiology, but careful dose monitoring is required.

Treatment patterns, overall survival, healthcare resource use and costs in elderly Medicare beneficiaries with chronic myeloid leukemia using second-generation tyrosine kinase inhibitors as second-line therapy

Objective Though the median age at diagnosis is 64 years, few studies focus on elderly (≥65 years) patients with chronic myeloid leukemia (CML). This study examines healthcare outcomes among elderly Medicare beneficiaries with CML who started nilotinib or dasatinib after imatinib. Research design and methods Patients were identified in the Medicare Research Identifiable Files (2006-2012) and had continuous Medicare Parts A, B, and D coverage. Main outcome measures Treatment patterns, overall survival (OS), monthly healthcare resource utilization and medical costs were measured from the second-line tyrosine kinase inhibitor (TKI) initiation (index date) to end of Medicare coverage. Results Despite similar adherence, dasatinib patients (N = 379) were more likely to start on the recommended dose (74% vs. 53%; p < 0.001), and to have dose reductions (21% vs. 11%, adjusted hazard ratio [HR] = 1.94; p = 0.002) or dose increases (9% vs. 7%; adjusted HR = 1.81; p = 0.048) than nilotinib patients (N = 280). Fewer nilotinib patients discontinued (59% vs. 67%; adjusted HR = 0.80; p = 0.026) or switched to another TKI (21% vs. 29%; adjusted HR = 0.72; p = 0.044) than dasatinib patients. Nilotinib patients had longer median OS (>4.9 years vs. 4.0 years; p = 0.032) and 37% lower mortality risk than dasatinib patients (adjusted HR = 0.63; p = 0.008). Nilotinib patients had 23% fewer inpatient admissions, 30% fewer emergency room visits, 13% fewer outpatient visits (all p < 0.05), and lower monthly medical costs (by $513, p = 0.024) than dasatinib patients. Limitations Lack of clinical assessment (disease phase and response to first-line therapy) and retrospective nature of study (unobservable potential confounding factors, non-randomized treatment choice). Conclusions In the current study of elderly CML patients, initiation of second-line TKIs frequently occurs at doses lower than the recommended starting doses and, despite this, many patients require dose adjustments. Here, nilotinib patients required fewer dose adjustments than dasatinib patients. Further research focusing on elderly CML patients is warranted in order to help define future best clinical practices.