Multi tyrosine kinase inhibitor dasatinib as novel cause of severe pre-capillary pulmonary hypertension?

A narrative review on adverse effects of dasatinib with a focus on pharmacotherapy of dasatinib-induced pulmonary toxicities

Chronic myeloid leukemia (CML), a myeloproliferative disorder caused by the over activity of BCR-ABL1 (breakpoint cluster region-Abelson), has been successfully treated by Tyrosine kinase inhibitors (TKIs). While imatinib is known as the first-line treatment of CML, in some cases other TKIs including dasatinib, nilotinib, bosutinib, and ponatinib may be preferred. Dasatinib, a second-generation TKI, inhibits multiple family kinases including BCR-ABL, SRC family kinases, receptor kinases, and TEC family kinases. It is effective against most imatinib-resistant cases except T315I mutation. Despite the superiority of dasatinib in its hematologic and cytogenetic responses in CML compared to imatinib, its potentially harmful pulmonary complications including pleural effusion (PE) and pulmonary arterial hypertension (PAH) may limit its use. Appropriate management of these serious adverse reactions is critical in both improving the quality of life and the outcome of the patient. In this narrative review, we will scrutinize the pulmonary complications of dasatinib and focus on the management of these toxicities.

Emerging antenatal therapies for congenital diaphragmatic hernia-induced pulmonary hypertension in preclinical models

Congenital diaphragmatic hernia (CDH)-related deaths are the largest contributor to in-hospital neonatal deaths in children with congenital malformations. Morbidity and mortality in CDH are directly related to the development of pulmonary hypertension (PH). Current treatment consists of supportive measures. To date, no pharmacotherapy has been shown to effectively reverse the hallmark finding of pulmonary vascular remodeling that is associated with pulmonary hypertension in CDH (CDH-PH). As such, there is a great need for novel therapies to effectively manage CDH-PH. Our review aims to evaluate emerging therapies, and specifically focuses on those that are still under investigation and not approved for clinical use by the Food and Drug Administration. Therapies were categorized into antenatal pharmacotherapies or antenatal regenerative therapies and assessed on their method of administration, safety profile, the effect on pulmonary vascular pathophysiology, and overall efficacy. In general, emerging antenatal pharmaceutical and regenerative treatments primarily aim to alleviate pulmonary vascular remodeling by restoring normal function and levels of key regulatory factors involved in pulmonary vascular development and/or in promoting angiogenesis. Overall, while these emerging therapies show great promise for the management of CDH-PH, most require further assessment of safety and efficacy in preclinical models before translation into the clinical setting. IMPACT: Emerging antenatal therapies for congenital diaphragmatic hernia-induced pulmonary hypertension (CDH-PH) show promise to effectively mitigate vascular remodeling in preclinical models. Further investigation is needed in preclinical and human studies to evaluate safety and efficacy prior to translation into the clinical arena. This review offers a comprehensive and up-to-date summary of emerging therapies currently under investigation in experimental animal models. There is no cure for CDH-PH. This review explores emerging therapeutic options for the treatment of CDH-PH and evaluates their impact on key molecular pathways and clinical markers of disease to determine efficacy in the preclinical stage.

Change of right ventricular systolic pressure can indicate dasatinib‐induced pulmonary arterial hypertension in chronic myeloid leukemia

Background

Methods

Results

Conclusions

Dasatinib-induced pulmonary arterial hypertension

Drug-induced (group 1) pulmonary hypertension (PH) is an important subgroup of PH involving dasatinib as a likely related agent, which is a second-generation tyrosine kinase inhibitor (TKI) used in the treatment of chronic myeloid leukaemia (CML). The mechanism of dasatinib-induced pulmonary arterial hypertension (PAH) is unclear. However, the occurrence of PAH with late onset in CML patients suggests a chronic pathological mechanism with an insidious onset rather than an acute inflammatory or cardiac aetiology. Dasatinib has a broader effect than other TKIs; the major known difference between dasatinib and other TKIs is the additional inhibition of Src family kinases. Therefore, Src inhibition was thought to play a role in the development of dasatinib-induced PAH. However, recently, it was also speculated that chronic dasatinib therapy may cause pulmonary endothelial damage, attenuate hypoxic pulmonary vasoconstriction responses and increase susceptibility to PAH independently of the Src family kinase-induced mechanism. Dasatinib-induced PAH usually seems to be reversible with the cessation of the drug, and sometimes with PAH-specific treatment strategies. Transthoracic echocardiography can be recommended as a routine screening prior to dasatinib initiation, and this non-invasive procedure can be utilized in patients having signs and symptoms attributable to PAH during dasatinib treatment.

Dasatinib-induced pulmonary arterial hypertension - A rare late complication

Dasatinib is a dual Src/Abl tyrosine kinase inhibitor approved for frontline and second line treatment of chronic phase chronic myelogenous leukemia. Pulmonary arterial hypertension is defined by an increase in mean pulmonary arterial pressure >25 mmHg at rest. Dasatinib-induced pulmonary hypertension has been reported in less than 1% of patients on chronic dasatinib treatment for chronic myelogenous leukemia. The pulmonary arterial hypertension from dasatinib may be categorized as either group 1 (drug-induced) or group 5 based on various mechanisms that may be involved including the pathogenesis of the disease process of chronic myelogenous leukemia. There have been reports of dasatinib-induced pulmonary arterial hypertension being reversible. We report a case of pulmonary arterial hypertension in a 46-year-old female patient with chronic phase chronic myelogenous leukemia on dasatinib treatment for over 10 years. She had significant improvement in symptoms after discontinuation of dasatinib and initiation of vasodilators. Several clinical questions arise once patients experience significant adverse effects as discussed in our case.

Dasatinib

Dasatinib is an oral available short-acting inhibitor of multiple tyrosine kinases. It was designed to inhibit ABL and SRC, but also has activity in multiple other kinases, including c-KIT, PDGFR-α, PDGFR-β, and ephrin receptor kinases. Dasatinib is a very potent inhibitor of BCR-ABL and an effective treatment for the BCR-ABL-driven diseases chronic myeloid leukemia (CML) and Philadelphia-chromosome-positive acute lymphoblastic leukemia (Ph+ ALL), characterized by the constitutively active tyrosine kinase, BCR-ABL. Dasatinib is approved for the treatment of CML (all phases) including children and for the treatment of Ph+ ALL, resistant or intolerant to prior imatinib treatment. Randomized trials in CML comparing dasatinib with imatinib show that first-line dasatinib causes significantly deeper and faster molecular remissions. In accelerated and blastic phase CML, as well as in Ph+ ALL, dasatinib frequently induces complete hematologic and cytogenetic remissions even in imatinib pretreated patients. Remissions however are often short. Dasatinib is administered independent of food intake as a once-daily dose of 100 mg in chronic phase CML and 140 mg in Ph+ ALL or blastic phase. Side effects of dasatinib are frequent but mostly moderate and manageable and include cytopenias and pleural effusions. The review presents the preclinical and clinical activity of dasatinib with a focus on clinical studies in CML.

Reversible Pulmonary Arterial Hypertension Induced by Dasatinib in a Patient With Chronic Myeloid Leukemia

A case study is provided of dasatinib-induced pulmonary arterial hypertension (PAH) in a patient with chronic myeloid leukemia. This condition resolved completely within 2 months of drug discontinuation. Transthoracic echocardiography (TTE) data were obtained throughout the recovery process. After 30 months of dasatinib treatment, a woman in her 30s developed orthopnea and signs of right heart failure (leg edema, hepatomegaly, and weight gain). Transthoracic echocardiography indicated elevated mean pulmonary artery pressure, severely impaired systolic and diastolic right ventricular functions, and dilation of the right ventricle and atrium. Once dasatinib was discontinued, clinical symptoms improved rapidly, and follow-up TTE 2 months later showed normal right heart function. Treatment with an alternative tyrosine kinase inhibitor was initiated and has continued without recurrence of PAH. This case suggests that dasatinib, which inhibits a broad spectrum of tyrosine kinases, could cause reversible PAH; therefore, careful cardiopulmonary evaluation by TTE is necessary.

Comparative analysis of pulmonary hypertension in patients treated with imatinib, nilotinib and dasatinib

Pulmonary hypertension (PH) is a rare, but life-threatening, adverse event in patients treated with tyrosine kinase inhibitors (TKIs), such as dasatinib, but has not been fully evaluated in patients treated with imatinib or nilotinib. We used echocardiography to noninvasively assess the incidence of PH in 105 patients with chronic myeloid leukaemia (CML) treated with imatinib (n = 37), nilotinib (n = 30) or dasatinib (n = 38). The mean triscupid regurgitation peak gradient (TRPG), which reflects pulmonary arterial pressure, was 22·7 mmHg in the imatinib group, 23·1 mmHg in the nilotinib group and 23·4 mmHg for dasatinib group. These values were not significantly different, but higher than those (19·0 mmHg) in newly diagnosed CML patients. A TRPG > 31 mmHg, marking possible PH onset, was detected in 9 of 105 patients: one (2·7%) treated with imatinib, three (10·0%) with nilotinib and five (13·2%) with dasatinib. Only three patients complained of dyspnoea, whereas the other six were asymptomatic. In addition, there was a tendency toward correlation of TRPG value and age or TKI treatment duration. These results suggested that treatment with not only dasatinib, but also imatinib and nilotinib, can be associated with subclinical PH. Noninvasive echocardiography is useful for screening, especially in older patients with long-term TKI treatment.

In vitro and in vivo evaluation of dasatinib and imatinib on physiological parameters of pulmonary arterial hypertension

PURPOSE

Pulmonary arterial hypertension (PAH) results from occlusion or vasoconstriction of pulmonary vessels, leading to progressive right ventricular failure. Dasatinib, a BCR-ABL1 tyrosine kinase inhibitor (TKI) approved for the treatment of chronic myelogenous leukemia, has been associated with PAH. In contrast, the BCR-ABL1 TKI imatinib has demonstrated anti-vasoproliferative properties and has been investigated as a potential treatment for PAH. Here we describe studies evaluating the effects of dasatinib and imatinib on cardiovascular and pulmonary functions to understand the reported differential consequences of the two TKIs in a clinical setting.

METHODS

The direct effects of dasatinib and imatinib were explored in vivo to investigate possible mechanisms of dasatinib-induced PAH. In addition, effects of dasatinib and imatinib on PAH-related mediators were evaluated in vitro.

RESULTS

In rats, both TKIs increased plasma nitric oxide (NO), did not induce PAH-related structural or molecular changes in PA or lungs, and did not alter hemodynamic lung function compared with positive controls. Similarly, in the pulmonary artery endothelial cells and smooth muscle cells co-culture model, imatinib and dasatinib increased NO and decreased endothelin-1 protein and mRNA.

CONCLUSIONS

The results of these studies indicated that dasatinib did not induce physiological changes or molecular signatures consistent with PAH when compared to positive controls. Instead, dasatinib induced changes consistent with imatinib. Both dasatinib and imatinib induced biochemical and structural changes consistent with a protective effect for PAH. These data suggest that other factors of unclear etiology contributed to the development of PAH in patients treated with dasatinib.

Imatinib relaxes the pulmonary venous bed of guinea pigs

Background

Recently, the IMPRES study revealed that systemic imatinib improves exercise capacity in patients with advanced pulmonary arterial hypertension. Imatinib blocks the tyrosine kinase activity of the platelet-derived growth factor (PDGF)-receptor (PDGFR), acts antiproliferative and relaxes pulmonary arteries. However so far, the relaxant effects of imatinib on pulmonary veins (PVs) and on the postcapillary resistance are unknown, although pulmonary hypertension (PH) due to left heart disease (LHD) is most common and primarily affects PVs. Next, it is unknown whether activation of PDGFR alters the pulmonary venous tone. Due to the reported adverse effects of systemic imatinib, we evaluated the effects of nebulized imatinib on the postcapillary resistance.

Methods

Precision-cut lung slices (PCLS) were prepared from guinea pigs. PVs were pre-constricted with Endothelin-1 (ET-1) and the imatinib-induced relaxation was studied by videomicroscopy; PDGF-BB-related vascular properties were evaluated as well. The effects of perfused/nebulized imatinib on the postcapillary resistance were studied in cavine isolated perfused lungs (IPL). Intracellular cAMP/cGMP was measured by ELISA in PVs.

Results

In PCLS, imatinib (100 μM) relaxed pre-constricted PVs (126%). In PVs, imatinib increased cAMP, but not cGMP and inhibition of adenyl cyclase or protein kinase A reduced the imatinib-induced relaxation. Further, inhibition of K_ATP-channels, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\mathrm{BK}}_{\mathrm{Ca}}^{2+} $$\end{document}BKCa2+-channels or K_v-channels diminished the imatinib-induced relaxation, whereas inhibition of NO-signaling was without effect. In the IPL, perfusion or nebulization of imatinib reduced the ET-1-induced increase of the postcapillary resistance. In PCLS, PDGF-BB contracted PVs, which was blocked by imatinib and by the PDGFR-β kinase inhibitor SU6668, whereas inhibition of PDGFR-α (ponatinib) had no significant effect. Conversely, PDGFR-β kinase inhibitors (SU6668/DMPQ) relaxed PVs pre-constricted with ET-1 comparable to imatinib, whereas the PDGFR-α kinase inhibitor ponatinib did not.

Conclusions

Imatinib-induced relaxation depends on cAMP and on the activation of K⁺-channels. Perfused or nebulized imatinib significantly reduces the postcapillary resistance in the pre-constricted (ET-1) pulmonary venous bed. Hence, nebulization of imatinib is feasible and might reduce systemic side effects. Conversely, PDGF-BB contracts PVs by activation of PDGFR-β suggesting that imatinib-induced relaxation depends on PDGFR-β-antagonism. Imatinib combines short-term relaxant and long-term antiproliferative effects. Thus, imatinib might be a promising therapy for PH due to LHD.

Axl Blockade by BGB324 Inhibits BCR-ABL Tyrosine Kinase Inhibitor-Sensitive and -Resistant Chronic Myeloid Leukemia

Purpose: BCR-ABL kinase inhibitors are employed successfully for chronic myeloid leukemia (CML) treatment. However, resistant disease and persistence of BCR-ABL1-independent leukemia stem and progenitor cells (LSPC) remain clinical challenges. The receptor tyrosine kinase Axl can mediate survival and therapy resistance of different cancer cells. We investigated the therapeutic potential of Axl inhibition in CML.Experimental Design: We used primary cells from patients with CML and TKI-sensitive and -resistant BCR-ABL1⁺ CML cell lines and a novel ponatinib-resistant cell line KCL-22 PonR. We analyzed the effects of genetic and pharmacologic Axl blockade by the small-molecule Axl inhibitor BGB324 in vitro and in vivo In BCR-ABL1-unmutated cells, we also investigated BGB324 in combination with imatinib.Results: We demonstrate overexpression of Axl receptor tyrosine kinase in primary cells of patients with CML compared with healthy individuals and a further increase of Axl expression in BCR-ABL TKI-resistant patients. We show that Axl blockage decreased growth of BCR-ABL TKI-sensitive CML cells including CD34⁺ cells and exerts additive effects with imatinib via inhibition of Stat5 activation. BGB324 also inhibits BCR-ABL TKI-resistant cells, including T315I-mutated and ponatinib-resistant primary cells. BGB324 exerted therapeutic effects in BCR-ABL1 T315I-mutated and ponatinib-resistant preclinical mouse models. Notably, BGB324 does not inhibit BCR-ABL1 and consequently inhibits CML independent of BCR-ABL1 mutational status.Conclusions: Our data show that Axl inhibition has therapeutic potential in BCR-ABL TKI-sensitive as well as -resistant CML and support the need for clinical trials. Clin Cancer Res; 23(9); 2289-300. ©2016 AACR.

Combination of White Blood Cell Count at Presentation With Molecular Response at 3 Months Better Predicts Deep Molecular Responses to Imatinib in Newly Diagnosed Chronic-Phase Chronic Myeloid Leukemia Patients

The aim of this study was to evaluate the impact of white blood cell (WBC) counts at presentation on the achievement of deep molecular response.A total of 362 newly diagnosed chronic-phase chronic myeloid leukemia patients (CML-CP) receiving 400 mg/day imatinib were serially monitored for a median of 36 months (range 6-115).Patients showing an optimal response at 3, 6, and 12 months as defined by the 2013 European LeukemiaNet recommendations had significantly lower WBC counts at presentation than those showing nonoptimal responses (all P < 0.0001). Among the cutoff values with a similar Youden index, 150 × 10E9/L (abbreviated WBC > 150) was selected to identify the greatest amount of patients with the potential to achieve a sustained molecular response of 4.5 (MR4.5). Regardless of whether the Sokal risk score was included, the BCR-ABL value at 3 months, WBC counts at presentation, hemoglobin levels, and sex were the common independent predictors for an MR4.5, with the former 2 presenting the highest hazard risk. Low Sokal risk scores did not independently predict the achievement of an MR4.5. Patients with concurrent WBC > 150 and BCR-ABL(IS) ≤ 10% had a similar incidence of 4-year MR4.5 compared with patients with concurrent WBC ≤ 150 and BCR-ABL(IS) > 10% and concurrent WBC > 150 and BCR-ABL(IS) > 10% (13.5% vs 13.2% vs 8.8%, P = 0.47), and all of these values were significantly lower than the values for patients with concurrent WBC ≤ 150 and BCR-ABL(IS) ≤ 10% (55.0%, all P < 0.0001). Patients with concurrent WBC ≤ 150 and BCR-ABL(IS) ≤ 10% had better 4-year event-free survival rates, progression-free survival rates, and overall survival rates compared with patients with WBC > 150 or BCR-ABL(IS) > 10%. The combination of WBC count at presentation and BCR-ABL(IS) at 3 months provides improved predictions of deep molecular response in imatinib-treated CML-CP patients. Therefore, the WBC count at presentation might be used to differentiate patients at the beginning of imatinib treatment.

Clinical features of pulmonary arterial hypertension in patients receiving dasatinib

The prognosis of most leukemia patients treated with BCR-ABL tyrosine kinase inhibitors (TKIs) is favorable, and a more precise understanding of serious and potentially irreversible treatment-related toxicities is essential to properly inform treatment choice. Few cases of pulmonary arterial hypertension (PAH) have been reported in patients with leukemia treated with dasatinib, a second-generation BCR-ABL TKI. To better understand characteristics and outcomes of dasatinib-treated patients with PAH, all clinical cases of PAH confirmed by right-heart catheterization in the Bristol-Myers Squibb pharmacovigilance database (N = 41), including 22 previously unpublished cases, were examined for previous treatments for leukemia, patient characteristics, time to PAH onset, and outcomes. Our analysis shows that compared with PAH due to other etiologies, dasatinib-related PAH is atypical, in that it is associated with partial to complete reversibility upon treatment discontinuation. The incidence of dasatinib-related PAH appears to be low. Most PAH cases were observed in patients who had received prior treatments for leukemia. No specific patient attributes appear to be associated with an increased risk of developing PAH while receiving dasatinib. Symptoms of PAH in dasatinib-treated leukemia patients should prompt a thorough workup, including consideration of confirmatory right-heart catheterization. In cases of confirmed PAH, dasatinib should be discontinued.

Cardiovascular and pulmonary adverse events in patients treated with BCR-ABL inhibitors: Data from the FDA Adverse Event Reporting System

Rare but serious cardiovascular and pulmonary adverse events (AEs) have been reported in patients with chronic myeloid leukemia treated with BCR-ABL inhibitors. Clinical trial data may not reflect the full AE profile of BCR-ABL inhibitors because of stringent study entry criteria, relatively small sample size, and limited duration of follow-up. To determine the utility of the FDA AE Reporting System (FAERS) surveillance database for identifying AEs possibly associated with the BCR-ABL inhibitors imatinib, dasatinib, and nilotinib in the postmarketing patient population, we conducted Multi-Item Gamma Poisson Shrinker disproportionality analyses of FAERS reports on AEs in relevant system organ classes. Signals consistent with the known safety profiles of these agents as well as signals for less well-described AEs were detected. Bone marrow necrosis, conjunctival hemorrhage, and peritoneal fluid retention events were uniquely associated with imatinib. AEs that most commonly reached the threshold for dasatinib consisted of terms relating to hemorrhage and fluid retention, including pleural effusion and pericardial effusion. Most terms that reached the threshold solely with nilotinib were related to peripheral and cardiac vascular events. Although this type of analysis cannot determine AE incidence or establish causality, these findings elucidate the AEs reported in patients treated with BCR-ABL inhibitors across multiple clinical trials and in the community setting for all approved and nonapproved indications, suggesting drug-AE associations warrant further investigation. These findings emphasize the need to consider patient comorbidities when selecting amongst BCR-ABL inhibitors.

Reversible Pulmonary Arterial Hypertension Associated with Dasatinib for Chronic Myeloid Leukemia

We describe two cases of pulmonary arterial hypertension (PAH) that occurred under dasatinib treatment and were resolved after dasatinib discontinuation. Two patients with chronic phase chronic myeloid leukemia (CML) were switched to dasatinib therapy because of hematological progress while receiving imatinib. These patients had New York Heart Association (NYHA) functional class II dyspnea with elevated right ventricular systolic pressure (RVSP), which progressed under dasatinib treatment. After dasatinib treatment was discontinued, subjective symptoms were improved to NYHA functional class I and the follow-up transthoracic Doppler echocardiography showed improved RVSP. Treatment with an alternate tyrosine kinase inhibitor was initiated and had been continued without development of dyspnea or elevation of RVSP. This report suggests that dasatinib can cause the reversible PAH, therefore, routine cardiopulmonary evaluation before and during treatment with dasatinib may be needed in CML patients with clinical manifestations.

Inhaled tyrosine kinase inhibitors for pulmonary hypertension: a possible future treatment

Pulmonary hypertension is a disease with severe consequences for the human body. There are several diseases and situations that induce pulmonary hypertension and are usually underdiagnosed. Treatments include conventional medical therapies and oral, inhaled, intravenous, and subcutaneous options. Depending on its severity, heart or lung transplant may also be an option. A possible novel treatment could be tyrosine kinase inhibitors. We conducted experiments with three jet nebulizers and three ultrasound nebulizers with erlotinib, gefitinib, and imatinib. Different residual cup designs and residual cup loadings were used in order to identify the best combination to produce droplets of less than 5 μm in mass median aerodynamic diameter. We found that gefitinib could not be transformed into a powder, so conversion to an aerosol form was not possible. Our experiments indicated that imatinib is superior to erlotinib with regard to small droplet size formation using both inhaled technologies (1.37 μm <2.23 μm and 1.92 μm <3.11 μm, jet and ultrasound, respectively) and, at jet devices (1.37 μm <1.92 μm). Cup designs C and G contribute best to small droplet creation uniquely supporting and equally well the activity of both drugs. The disadvantage of the large droplets formed for erlotinib was offset when combined with residual cup C (1.37 μm instead of 2.23 μm). At a 2 mL dose, the facemask and cone mouthpieces performed best and evenly; the facemask and low dose were the best choice (2.08 μm and 2.12 μm, respectively). Erlotinib and imatinib can be administered as an aerosols, and further in vivo experimentation is necessary to investigate the positive effects of these drugs in the treatment of pulmonary hypertension.

Dasatinib

Dasatinib is an orally available short-acting dual ABL/SRC tyrosine kinase inhibitor (TKI). It potently inhibits BCR-ABL and SRC family kinases (SRC, LCK, YES, FYN), but also c-KIT, PDGFR-α and PDGFR-β, and ephrin receptor kinase. Dasatinib is an effective treatment for chronic myeloid leukemia (CML) and Philadelphia chromosome positive acute lymphoblastic leukemia (Ph+ ALL). Both diseases are characterized by a constitutively active tyrosine kinase; BCR-ABL. Dasatinib inhibits BCR-ABL with greater potency compared with other BCR-ABL inhibitors and is active in CML resistant or intolerant to imatinib. Dasatinib is approved for the treatment of CML (all phases) and for the treatment of Ph+ ALL, resistant or intolerant to prior imatinib treatment. Randomized trial data in CML show that first-line dasatinib provides superior responses compared with imatinib and enables patients to achieve early, deep responses, correlated with improved longer-term outcomes. A once-daily dose of 100 mg in chronic phase CML results in high hematologic and molecular remission rates and prolongation of survival. In accelerated and blastic phase of CML, as well as in Ph+ ALL, complete hematologic and cytogenetic remissions frequently occur. Remissions however are very short. In these patients, once-daily 140 mg is the recommended dose. The effect of dasatinib in other malignancies including solid tumors is subject of clinical studies. Regardless of many clinical trials in different tumor types and in different combinations of dasatinib with other agents, the role of dasatinib in the treatment of solid tumors has not yet been defined. Side effects of dasatinib are frequent but mostly moderate and manageable and include cytopenias and pleural effusions. The review presents the preclinical and clinical activity of dasatinib with a focus on clinical studies in CML.

The development of dasatinib as a treatment for chronic myeloid leukemia (CML): from initial studies to application in newly diagnosed patients

PURPOSE

Dasatinib is a dual Abl/Src tyrosine kinase inhibitor (TKI) designed as a prototypic short-acting BCR-ABL-targeted TKI that inhibits BCR-ABL with greater potency compared with imatinib, nilotinib, bosutinib, and ponatinib and has been shown to have potential immunomodulatory effects. Dasatinib is approved for the treatment of all phases of chronic myeloid leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia resistant or intolerant to prior imatinib treatment and first-line treatment for CML in chronic phase. In this article, the development of dasatinib as a treatment for patients with CML is reviewed.

METHODS

This is a review of the relevant literature regarding dasatinib development in CML (2003-2013).

RESULTS

Dasatinib demonstrates efficacy against most BCR-ABL mutations arising during imatinib therapy and is effective in treating patients with imatinib resistance due to other mechanisms. Randomized trial data show that first-line dasatinib provides superior responses compared with imatinib and enables patients to achieve early, deep responses correlated with improved longer-term outcomes. Dasatinib has a generally acceptable safety profile, with most adverse events (AEs) proving manageable and reversible. Cytopenias are commonly observed with dasatinib, and some nonhematologic AEs including pleural effusion have been consistently reported.

CONCLUSION

Dasatinib is an effective treatment option for patients with CML.

A critical review of trials of first-line BCR-ABL inhibitor treatment in patients with newly diagnosed chronic myeloid leukemia in chronic phase

BACKGROUND

The characteristic expression of the constitutively active oncoprotein, BCR-ABL tyrosine kinase, in chronic myeloid leukemia (CML) was the basis for the development of BCR-ABL tyrosine kinase inhibitors for treatment. Three BCR-ABL inhibitors, imatinib, nilotinib, and dasatinib, have been approved by the US Food and Drug Administration for first-line treatment of patients with newly diagnosed CML in chronic phase (CML-CP).

METHODS

This article reviews the key phase III clinical trials supporting the use of first-line imatinib, nilotinib, and dasatinib in patients with CML-CP, as well as findings of supportive phase II studies.

RESULTS

At the time of its approval in 2001, imatinib induced unprecedented response rates in patients with CML-CP; however, resistance and intolerance to imatinib prevent 20% to 30% of patients from deriving full therapeutic benefit. Nilotinib and dasatinib, both approved in 2010 for first-line CML-CP treatment, are more potent than imatinib and less susceptible to imatinib resistance mechanisms. Comparative clinical trials of each agent with imatinib have shown that they are associated with significantly deeper and more rapid responses than standard-dose imatinib, without compromising safety.

CONCLUSIONS

Given that evidence suggests achievement of an early response is predictive of improved long-term outcomes, earlier use of these compounds may lead to more rapid, deeper responses corresponding with improvements in patient outcome. Although future studies will benefit from more uniform definitions of end points and methods of analysis, data from published studies of first-line BCR-ABL inhibitor treatment for patients with newly diagnosed CML-CP support the use of dasatinib or nilotinib in place of imatinib.

World Health Organization group 5 pulmonary hypertension

World Health Organization (WHO) group 5 pulmonary hypertension (PH) entails a heterogeneous group of disorders that may cause PH by unclear and/or multiple mechanisms. In particular, group 5 includes PH caused by hematologic disorders, systemic diseases, metabolic disorders, chronic renal failure, and disorders leading to pulmonary vascular occlusion or compression. This article discusses common pathogenic mechanisms leading to group 5 PH, followed by a detailed overview of epidemiology, pathogenesis, and disease-specific management of the individual group 5 conditions. Off-label use of vasomodulatory therapies, typically indicated for pulmonary arterial hypertension (WHO group 1 PH), in group 5 conditions is also discussed.

Circulating angiogenic modulatory factors predict survival and functional class in pulmonary arterial hypertension

The diagnosis of pulmonary arterial hypertension (PAH) is frequently delayed. We hypothesized that circulating angiogenic modulatory protein levels might correspond with vascular remodeling activity and serve as sensitive biomarkers of PAH. Levels of soluble endoglin (sEng), soluble vascular endothelial growth factor receptor-1 (sVEGFR1), N-terminal brain natriuretic peptide (NT-proBNP), C-reactive protein (CRP), and other biomarkers were measured in peripheral blood from 97 PAH patients, 16 first-degree relatives of idiopathic or heritable pulmonary arterial hypertension (HPAH) patients, and 56 controls, and correlated with disease, functional class, hemodynamic parameters, exercise capacity, and transplant-free survival. Endoglin expression was analyzed in lung tissues of six individuals with idiopathic or HPAH and four individuals without PAH. Levels of sEng, sVEGFR1, CRP, and NT-proBNP were elevated in Group I PAH of diverse etiologies, with sEng performing better than NT-proBNP in detecting PAH (receiver operator characteristic-area-under-the curve [ROC-AUC] of 0.82 ± 0.03 vs. 0.71 ± 0.05, P = 0.016). While sEng, sVEGFR1, and NT-proBNP correlated with New York Heart Association (NYHA) class, sEng levels were more sensitive than NT-proBNP in detecting NYHA Class I-II disease (ROC-AUC of 0.88 ± 0.05 vs. 0.67 ± 0.08, P = 0.028). sEng, sVEGFR1, CRP, and NT-proBNP predicted transplant-free survival by univariate Cox regression. After adjusting for NT-proBNP levels, each of the other three markers predicted transplant-free survival. In multivariate analysis, sEng and CRP were independent predictors of survival. Endoglin expression was markedly enhanced in the microvascular endothelium and endovascular lesions of PAH versus control lung tissues. Circulating angiogenic proteins sEng and sVEGFR1 are sensitive markers of prognosis and function in Group I PAH, including mildly symptomatic disease, and may provide unique noninvasive data reflecting underlying remodeling activity.

Cardiovascular Toxicity of Molecular Targeted Therapy in Cancer Patients: A Double-Edged Sword

The annual incidence of cancer has increased over the past 20 years, yet the 5-year relative survival rate for cancer has improved with the increasing availability of advanced therapies, including molecular targeted therapy. Cardiovascular toxicity can develop with this type of targeted therapy, which can cause serious side effects including left ventricular dysfunction, hypertension, hypotension, QT prolongation, thromboembolism, and myocardial ischemia. In many ways, the quality of life primarily depends on the health status of patient cardiopulmonary function. However, risk factor assessment, routine monitoring, and prompt intervention remain the best strategy to deal with these patients with malignancies, to ensure that their cardiopulmonary function is maintained at the highest possible level. Most previous studies on cardiovascular toxicity have focused on conventional chemotherapy. Molecular targeted therapy is a novel anticancer treatment; however, due to potentially adverse cardiovascular events from this therapy, oncologists and cardiologists need to work together to maximize the benefits. In this review, we focused on target therapy-induced cardiovascular toxicities, in particular cardiac structural, electrophysiological, and vascular effects.

KEY WORDS

Cardiovascular toxicity; Molecular target therapy.

Targeting the PDGF signaling pathway in the treatment of non-malignant diseases

Platelet-derived growth factor (PDGF) is a family of mesenchymal mitogens with important functions during the embryonal development and in the control of tissue homeostasis in the adult. The PDGF isoforms exert their effects by binding to α-and β-tyrosine kinase receptors. Overactivity of PDGF signaling has been linked to the development of certain malignant and non-malignant diseases, including atherosclerosis and various fibrotic diseases. Different types of PDGF antagonists have been developed, including inhibitory monoclonal antibodies and DNA aptamers against PDGF isoforms and receptors, and receptor tyrosine kinase inhibitors. Beneficial effects have been recorded using such inhibitors in preclinical models and in patients with certain malignant as well as non-malignant diseases. The present communication summarizes the use of PDGF antagonists in the treatment of non-malignant diseases.

Rapid mobilization of cytotoxic lymphocytes induced by dasatinib therapy

Tyrosine kinase inhibitors (TKIs) have potent effects on malignant cells, and they also target kinases in normal cells, which may have therapeutic implications. Using a collection of 55 leukemia patients treated with TKI therapy (chronic myeloid leukemia, n=47; acute lymphoblastic leukemia, n=8), we found that dasatinib, a second-generation broad-spectrum TKI, induced a rapid, dose-dependent and substantial mobilization of non-leukemic lymphocytes and monocytes in blood peaking 1-2 h after an oral intake and the blood counts closely mirrored drug plasma concentration. A preferential mobilization was observed for natural killer (NK), NK T, B and γδ+ T cells. Mobilization was coupled with a more effective transmigration of leukocytes through an endothelial cell layer and improved cytotoxicity of NK cells. Platelet numbers decreased markedly after the drug intake in a proportion of patients. Similar effects on blood cell dynamics and function were not observed with any other TKI (imatinib, nilotinib and bosutinib). Thus, dasatinib induces a unique, rapid mobilization and activation of cytotoxic, extravasation-competent lymphocytes, which may not only enhance antileukemia immune responses but can also be causally related to the side-effect profile of the drug (pleural effusions, thrombocytopenia).

Managing chronic myeloid leukemia patients intolerant to tyrosine kinase inhibitor therapy

The outcomes for patients with chronic myeloid leukemia have improved dramatically with the development and availability of BCR-ABL1 tyrosine kinase inhibitors (TKIs) over the past decade. TKI therapy has a superior safety profile compared with the previous standard of care, interferon-α, and most adverse events (AEs) observed with front-line and second-line TKI treatment are managed with supportive care. However, some patients are intolerant to TKI therapy and experience AEs that cannot be managed through dose reduction or symptomatic treatment. Careful management of AEs helps patients to remain adherent with treatment and increases their chances for successful outcomes. Proactive vigilance for potential AEs and treatment strategies that reduce symptom burden will help to minimize patient intolerance. This review discusses the most common AEs associated with intolerance to TKI therapy and treatment strategies to help manage patients at risk for or experiencing these events.

Dasatinib for the treatment of Philadelphia chromosome-positive leukemias

INTRODUCTION

Dasatinib is a dual Abl/Src tyrosine kinase inhibitor (TKI), which was developed to treat patients with chronic myelogenous leukemia (CML), who had failed or were intolerant to therapy with imatinib.

AREAS COVERED

In this article, we review preclinical and clinical studies with dasatinib for the therapy of Philadelphia (Ph)-positive leukemias.

EXPERT OPINION

Dasatinib is very effective in the setting of CML resistance or intolerance to imatinib, particularly in patients in chronic phase (CP). Dasatinib is also effective against most BCR-ABL1 mutations that arise during therapy with imatinib. Further studies have confirmed activity of dasatinib as a single-agent, and combined with chemotherapy, for the treatment of patients with Philadelphia-positive acute lymphoblastic leukemia (Ph+-ALL). More recently, randomized trials have demonstrated that dasatinib is superior to imatinib in the initial therapy of patients with CML, and the drug was approved by the FDA for this indication in 2011.

Targeting PDGF pathway in pulmonary arterial hypertension

INTRODUCTION

Pulmonary arterial hypertension (PAH) encompasses a rare potentially lethal group of diseases characterized by vasoconstriction, in situ thrombosis and vascular remodeling. Most of the existing therapies including endothelin receptor antagonists, prostacyclin and derivatives, or phsophodiesterase-5 inhibitors tackle mainly the endothelial dysfunction, leaving the remodeling suboptimally inhibited. This explains the disease progression that occurs even with combined therapies and the need for other therapies able to adequately inhibit the vascular remodeling.

AREAS COVERED

Platelet-derived growth factor (PDGF) signaling pathway was demonstrated to be involved in the vascular remodeling in PAH, and therefore, it might be a desirable therapeutic target in this setting. This review discusses the pathogenic role of this pathway in PAH and its potential inhibitory approaches, focusing on imatinib as well as on the existing preclinical data on this compound.

EXPERT OPINION

Preclinical studies demonstrated that PDGF inhibition with receptor antagonists such as imatinib reduces vascular remodeling. Therefore, PDGF might represent a plausible therapeutic target in this disease. However, compounds able to block this pathway via different mechanisms might also become potential PAH therapies.

Pathobiology of pulmonary arterial hypertension and right ventricular failure

Pulmonary arterial hypertension (PAH) is no longer an orphan disease. There are three different classes of drugs for the treatment of PAH that are currently being used and an increasing number of patients are being treated with a single drug or combination therapy. During the last 25 yrs, new insights into the pathobiology of PAH have been gained. The classical mechanical concepts of pressure, flow, shear stress, right ventricle wall stress and impedance have been complemented with the new concepts of cell injury and repair and interactions of complex multicellular systems. Integrating these concepts will become critical as we design new medical therapies in order to change the prognosis of patients with these fatal diseases. This review intends to summarise recent pathobiological concepts of PAH and right ventricle failure mainly derived from human studies, which reflect the progress made in the understanding of this complex group of pulmonary vascular diseases.

Off-target effects of BCR-ABL1 inhibitors and their potential long-term implications in patients with chronic myeloid leukemia

In patients with chronic myeloid leukemia (CML), use of the BCR-ABL1-specific tyrosine kinase inhibitors (TKIs) imatinib, nilotinib and dasatinib has greatly improved patient survival and prolonged disease remission. More than 10 years of data from imatinib clinical studies and many years of data for nilotinib and dasatinib have demonstrated that these TKIs are well tolerated in most patients with CML. However, these inhibitors are not entirely BCR-ABL1-specific, and this lack of specificity could account for the off-target effects of these drugs. Adverse events (AEs) are off-target effects that are detrimental to the patient. The underlying mechanisms that contribute to these effects are poorly understood and the long-term consequences of chronic TKI therapy remain largely unknown, particularly with the newer agents. Here, we review the preclinical and clinical data for several of the more frequent AEs associated with TKIs and discuss the therapeutic relevance of these AEs for patients with CML.

Role of Src tyrosine kinases in experimental pulmonary hypertension

OBJECTIVE

Pulmonary arterial hypertension is a progressive pulmonary vascular disorder with high morbidity and mortality. Compelling evidence suggests that receptor tyrosine kinases, such as platelet-derived growth factor (PDGF) are closely involved in the pathogenesis of pulmonary arterial hypertension. We investigated the effects of 2 novel PDGF inhibitors, nilotinib/AMN107 (Abl kinases/PDGF receptor inhibitor) and dasatinib/BMS-354825 (Abl kinases/PDGF receptor/Src inhibitor), on the proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs) and on the hemodynamics and pulmonary vascular remodeling in experimental pulmonary hypertension, and determined the expression and regulation of Src family kinases.

METHODS AND RESULTS

Human PASMCs were stimulated by PDGF alone or multiple growth factors to induce proliferation and migration in vitro. Dasatinib (0.03 μmol/L), nilotinib (0.3 μmol/L), and imatinib (1 μmol/L) potently inhibited PDGF-induced signal transducer and activator of transcription 3 and Akt phosphorylation. All 3 inhibitors decreased PDGF-induced proliferation, cell cycle gene regulation, and migration. In contrast, only dasatinib inhibited multiple growth factor-induced PASMC proliferation, and this was associated with the inhibition of Src phosphorylation. Combination of specific Src inhibitors (phosphoprotein phosphatase 1, phosphoprotein phosphatase 2) with either imatinib or nilotinib reduced multiple growth factor-induced proliferation to a similar extent as dasatinib. Importantly, Src phosphorylation increased in pulmonary arterial hypertension PASMCs compared with control PASMCs. Finally, in vivo dasatinib (15 mg/kg per body weight) treatment caused a complete reversal of pulmonary vascular remodeling and achieved similar effectiveness as imatinib (100 mg/kg per body weight) in both monocrotaline- and hypoxia-induced pulmonary hypertension models.

CONCLUSIONS

We suggest that dual inhibition of PDGF receptor and Src kinases potently inhibits mitogenic and motogenic responses to growth factors in PASMCs and pulmonary vascular remodeling in vivo so that dual inhibition may represent an alternative therapeutic approach for pulmonary arterial hypertension.

Pulmonary arterial hypertension in patients treated by dasatinib

BACKGROUND

The French pulmonary hypertension (PH) registry allows the survey of epidemiological trends. Isolated cases of precapillary PH have been reported in patients who have chronic myelogenous leukemia treated with the tyrosine kinase inhibitor dasatinib.

METHODS AND RESULTS

This study was designed to describe incident cases of dasatinib-associated PH reported in the French PH registry. From the approval of dasatinib (November 2006) to September 30, 2010, 9 incident cases treated by dasatinib at the time of PH diagnosis were identified. At diagnosis, patients had moderate to severe precapillary PH with functional and hemodynamic impairment. No other incident PH cases were exposed to other tyrosine kinase inhibitors at the time of PH diagnosis. Clinical, functional, or hemodynamic improvements were observed within 4 months of dasatinib discontinuation in all but 1 patient. Three patients required PH treatment with endothelin receptor antagonist (n=2) or calcium channel blocker (n=1). After a median follow-up of 9 months (min-max 3-36), the majority of patients did not demonstrate complete clinical and hemodynamic recovery, and no patients reached a normal value of mean pulmonary artery pressure (≤20 mm Hg). Two patients (22%) died at follow-up (1 of unexplained sudden death and 1 of cardiac failure in the context of septicemia, respectively, 8 and 12 months after dasatinib withdrawal). The lowest estimate of incident PH occurring in patients exposed to dasatinib in France was 0.45%.

CONCLUSIONS

Dasatinib may induce severe precapillary PH fulfilling the criteria of pulmonary arterial hypertension, thus suggesting a direct and specific effect of dasatinib on pulmonary vessels. Improvement is usually observed after withdrawal of dasatinib.

Pulmonary arterial hypertension caused by treatment with dasatinib for chronic myeloid leukemia -critical alert-

We present a case of pulmonary arterial hypertension (PAH), which is potentially related to treatment with dasatinib (Sprycel(®)). A 61-year-old woman, who had been treated with dasatinib for 27 months for chronic myeloid leukemia (CML), visited our hospital complaining of dyspnea. In right heart catheterization, her mean pulmonary arterial pressure was 35 mmHg. After other possible etiologies to cause PAH were excluded, the patient was diagnosed as a dasatinib-related PAH. As notified by U.S. Food and Drug Administration (FDA) in October 2011, we recommend routine cardiopulmonary evaluation before and during treatment with dasatinib in CML patients in terms of the adverse effects of PAH.

Imatinib mesylate for the treatment of pulmonary arterial hypertension

INTRODUCTION

Despite recent advances, pulmonary arterial hypertension (PAH) remains a devastating disease which harbors a poor prognosis. Novel therapeutic approaches directly targeting pulmonary vascular remodeling are warranted.

AREAS COVERED

This review delineates the current limitations in the management of PAH and focuses on a novel, anti-proliferative therapeutic concept. It will help readers understand the mechanisms of receptor tyrosine kinase signaling, with a special focus on platelet-derived growth factor (PDGF) receptors and their role in the pathobiology of PAH. Furthermore, it provides a comprehensive summary regarding the rationale, efficacy and safety of the tyrosine kinase inhibitor imatinib mesylate , which potently inhibits the PDGF receptor, as an additional treatment option in PAH.

EXPERT OPINION

PDGF is a potent mitogen for pulmonary vascular smooth muscle cells and represents an important mediator of pulmonary vascular remodeling. Imatinib mesylate, a compound that inhibits the Bcr-Abl kinase and was developed for the treatment of chronic myeloid leukemia, also targets PDGF receptors. Both experimental and clinical data indicate that it reverses the vascular remodeling process even when it is fully established. Results from Phase II and III clinical trials suggest potent and prolonged efficacy in patients with severe PAH (i.e., pulmonary vascular resistance > 800 dynes*s*cm(-5)). Future studies should evaluate the long-term clinical efficacy and safety of imatinib, including patients with less impaired hemodynamics. Based on the current knowledge, this compound is likely to become an additional treatment option for patients with PAH and has the potential to at least partially correct the pathology of the disease.