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

Imatinib Mesylate Causes Potential Cardiac Dysfunction in Patients With Chronic Myeloid Leukemia: the Results of a Case-control Study

Unlike second-generation tyrosine kinase inhibitors, effects of imatinib on the cardiovascular (CV) system are debatable. The current case-control study aimed to evaluate the CV effects of imatinib in patients with chronic myeloid leukemia (CML) using non-invasive 2D-echocardiography testing. Patients with CML ≥ 13 years attending the adult haematology clinic of a tertiary care hospital in north India were prospectively enrolled over 1.5 years. The study population (n = 110) consisted of 35 newly diagnosed patients (treatment-naïve group) and 75 patients under imatinib therapy ≥ 1 year (treated group). All the eligible patients were subjected to 2D-echocardiography to calculate pulmonary artery systolic pressure (PASP), left ventricular ejection fraction (LVEF) and deceleration time (DT). These parameters were compared between the two groups. P-value < 0.05 was considered statistically significant. The median age of study population was 40 years (range, 13-73) and M:F ratio was 1.14:1. Both the groups had similar demographics at the diagnosis including CV risk factors. The median PASP of the treated group was 2 mm Hg higher than the treatment-naïve group (25 vs 23 mm Hg, p-value = 0.919). The median LVEF of the treated group was 3.2% lower than the treatment-naïve group (58.5% vs 61.72%, p-value = 0.577). The median DT of the treated group was 7 ms shorter than treatment-naïve group (211 vs 204 ms, p-value = 0.411). Imatinib causes potential cardiac dysfunction in patients with CML. Large scale prospective follow-up trials in the same cohort of patients are needed to validate the findings of our study.

Chronic myeloid leukaemia: Biology and therapy

Chronic myeloid leukaemia (CML) is caused by BCR::ABL1. Tyrosine kinase-inhibitors (TKIs) are the initial therapy. Several organizations have reported milestones to evaluate response to initial TKI-therapy and suggest when a change of TKI should be considered. Achieving treatment-free remission (TFR) is increasingly recognized as the optimal therapy goal. Which TKI is the best initial therapy for which persons and what depth and duration of molecular remission is needed to achieve TFR are controversial. In this review we discuss these issues and suggest future research directions.

Pulmonary arterial hypertension nanotherapeutics: New pharmacological targets and drug delivery strategies

Pulmonary arterial hypertension (PAH) is a rare, serious, and incurable disease characterized by high lung pressure. PAH-approved drugs based on conventional pathways are still not exhibiting favorable therapeutic outcomes. Drawbacks like short half-lives, toxicity, and teratogenicity hamper effectiveness, clinical conventionality, and long-term safety. Hence, approaches like repurposing drugs targeting various and new pharmacological cascades and/or loaded in non-toxic/efficient nanocarrier systems are being investigated lately. This review summarizes the status of conventional, repurposed, either in vitro, in vivo, and/or in clinical trials of PAH treatment. In-depth description, discussion, and classification of the new pharmacological targets and nanomedicine strategies with a description of all the nanocarriers that showed promising efficiency in delivering drugs are discussed. Ultimately, an illustration of the different nucleic acids tailored and nanoencapsulated within different types of nanocarriers to restore the pathways affected by this disease is presented.

Variables associated with pulmonary hypertension screened by echocardiography in chronic myeloid leukemia patients on dasatinib therapy

Background

Pulmonary hypertension (PH) is a rare but life-threatening adverse event (AE) of dasatinib, but the associated variables are not clear. This study aimed to explore the variables associated with PH by echocardiography in patients with chronic myeloid leukemia in the chronic phase (CML-CP) receiving dasatinib therapy.

Methods

Echocardiography was performed to estimate the probability of PH and pulmonary artery systolic pressure (PASP). Binary logistic analysis and Fine–Gray hazard model were used to identify the variables associated with PH by using cross-sectional and longitudinal data.

Results

Among the 243 patients in the cross-sectional dataset, with a median dasatinib therapy duration of 27 months, 30 (12.3%) were classified as having a high probability of PH. Increasing age (OR = 1.7, p = 0.002; OR = 1.5, p = 0.003) and pericardial effusion (OR = 4.3, p = 0.004; OR = 3.2, p = 0.014) were significantly associated with a high probability of PH and PASP ≥ 40 mmHg, respectively. Among the 161 patients in the longitudinal dataset, the 3-year cumulative incidences of a high probability of PH and PASP ≥ 40 mmHg were 9.3% and 22.1%, respectively. Pericardial effusion (HR = 3.8, p = 0.005) and cardiopulmonary comorbidities (HR = 3.2, p = 0.021) were significantly associated with a high probability of PH; increasing age (HR = 1.5, p &lt; 0.001) and dasatinib as ≥ 3rd-line therapy (p = 0.032; 2nd-line vs. 1st-line, HR = 2.0, p = 0.200; ≥ 3rd-line vs. 1st-line, HR = 3.4, p = 0.047) were significantly associated with PASP ≥ 40 mmHg.

Conclusion

Increasing age, pericardial effusion, cardiopulmonary comorbidities, and dasatinib as ≥ 3rd-line TKI therapy were associated with PH in the patients with CML-CP on dasatinib therapy.

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.

Pulmonary hypertension in patients with chronic myeloid leukemia

Dasatinib, a tyrosine kinase inhibitor (TKI), induces pulmonary hypertension (PH) in patients with chronic myeloid leukemia (CML). However, information on other TKIs is limited.We retrospectively analyzed PH prevalence by reviewing transthoracic echocardiography (TTE) findings in a population of Korean CML patients treated with TKI at a single hospital between 2003 and 2020. PH was defined as a high PH probability according to the European Society of Cardiology/European Respiratory Society (ESC/ERS) guidelines.Of the 189 patients treated with TKI(s) during the study period, 112 (59.3%) underwent TTE. Among the 112 patients treated with a TKI for a median of 40.4 months (range: 1.1-167.2 months), PH was found in 12 (10.7%), most frequently in those treated with dasatinib (ie, in 3 [7.5%] of 40 of those treated with imatinib, 1 [3.1%] of 32 of those treated with nilotinib, and 8 [21.6%] of 37 of those treated with dasatinib). PH resolved in 4 (50.0%) of the 8 dasatinib-treated patients after discontinuation of the agent. One nilotinib-treated and all three imatinib-treated patients recovered from PH. In multivariate analyses, age >60 years, dasatinib treatment, and positive cardiopulmonary symptoms/signs at the time of transthoracic echocardiography were statistically significant risk factors for developing PH.These results show that PH is induced not only by dasatinib, but also by imatinib and nilotinib. Careful screening for PH during any TKI treatment may thus be warranted in patients with CML.

mTOR Signaling in Pulmonary Vascular Disease: Pathogenic Role and Therapeutic Target

Pulmonary arterial hypertension (PAH) is a progressive and fatal disease without a cure. The exact pathogenic mechanisms of PAH are complex and poorly understood, yet a number of abnormally expressed genes and regulatory pathways contribute to sustained vasoconstriction and vascular remodeling of the distal pulmonary arteries. Mammalian target of rapamycin (mTOR) is one of the major signaling pathways implicated in regulating cell proliferation, migration, differentiation, and protein synthesis. Here we will describe the canonical mTOR pathway, structural and functional differences between mTOR complexes 1 and 2, as well as the crosstalk with other important signaling cascades in the development of PAH. The pathogenic role of mTOR in pulmonary vascular remodeling and sustained vasoconstriction due to its contribution to proliferation, migration, phenotypic transition, and gene regulation in pulmonary artery smooth muscle and endothelial cells will be discussed. Despite the progress in our elucidation of the etiology and pathogenesis of PAH over the two last decades, there is a lack of effective therapeutic agents to treat PAH patients representing a significant unmet clinical need. In this review, we will explore the possibility and therapeutic potential to use inhibitors of mTOR signaling cascade to treat PAH.

Evaluation of hemodynamic parameters among patients with myeloproliferative neoplasms and suspected pulmonary hypertension

Myeloproliferative neoplasms (MPNs) are associated with pulmonary hypertension (PH). We studied MPN patients who underwent right-heart-catheterization (RHC) to identify hemodynamic differences between MPN-subtypes. Per RHC, hemodynamics were classified as pre, post or combined pre and post-capillary PH. One-way analysis-of-variance (ANOVA) was used to compare hemodynamic differences among MPN-subtypes. Correlation of RVSP between trans-thoracic echocardiography (TTE) and RHC was evaluated. We included 68 patients. Median age was 63. Fifty-nine percent were male and 87% Caucasian. Polycythemia vera and essential thrombocythemia were the most common subtypes. On TTE, 91.5% had PH. On RHC, only 29% met criteria for pre-capillary PH. No MPN-subtype was more likely than others to have pre-capillary PH. Bland-Altman analysis showed significant intra-person variability between TTE and RHC-derived right ventricular systolic pressures. Post-capillary involvement is more common than precapillary PH in MPN. Type of PH does not appear to differ by MPN-subtype.

Treatment free remission in chronic myeloid leukemia: Lights and shadows

In addition to the best possible overall survival, discontinuation of the tyrosine kinase-inhibitor (TKI) treatment [treatment free remission (TFR)] without observing a recurrence of the disease has become a standard part of chronic myeloid leukemia (CML) care. Worldwide, more than 2000 patients with CML have attempted TFR, and very rare instances of disease transformation have been reported. Several studies in the last decade have demonstrated the feasibility and safety of TKI discontinuation in selected patients with CML who achieve deep and sustained molecular response with TKI. This has moved prime-time into clinical practice although open questions remain in terms of understanding the disease biology that leads to successful TKI cessation in some patients while not in others. Despite the remaining questions regarding which factors may be considered predictive for TFR, treatment interruption is a safe option provided that adequate molecular monitoring is available, with prompt re-initiation of TKIs as soon as major molecular response has been lost. Data from ongoing trials should help refine decisions as to which patients are the best candidates to attempt TKI discontinuation, frequency of a safe monitoring, optimal strategies to sustain ongoing TFR and increase the number of patients who can access to discontinuation programs.

A 59-Year-Old Woman With Shortness of Breath and Chest Pain

CASE PRESENTATION

A 59-year-old woman presented to the ED with syncope. She had progressive shortness of breath with minimal activity and precordial resting chest pain for 1 month prior to presentation. She had a medical history of heart failure with preserved ejection fraction, severe OSA well controlled with CPAP of 11 cm H₂O, and a history of DVT and pulmonary embolism, diagnosed 10 years ago for which she was maintained on warfarin. The patient also had chronic myeloid leukemia in the chronic phase; she had initially been treated with imatinib but was later switched to dasatinib about 4.5 years prior to presentation. The patient had achieved major molecular remission with dasatinib 140 mg daily. Her family history was noncontributory and specifically negative for pulmonary hypertension and heart failure. She had a history of smoking (50 pack years) but had quit 23 years ago.

Current Strategies and Future Directions to Achieve Deep Molecular Response and Treatment-Free Remission in Chronic Myeloid Leukemia

The treatment of chronic myeloid leukemia (CML) has been radically changed by the approval of tyrosine kinase inhibitors (TKIs), which target BCR-ABL1 kinase activity. CML is now managed as a chronic disease requiring long-term treatment and close molecular monitoring. It has been shown that in a substantial number of patients who have achieved a stable deep molecular response (DMR), TKI treatment can be safely discontinued without loss of response. Therefore, treatment-free remission (TFR), through the achievement of a DMR, is increasingly regarded as a feasible treatment goal in many CML patients. However, only nilotinib has approval in this setting and a number of controversial aspects remain regarding treatment choices and timings, predictive factors, patient communication, and optimal strategies to achieve successful TFR. This narrative review aims to provide a comprehensive overview on how to optimize the path to DMR and TFR in patients with CML, and discusses recent data and future directions.

Analysis of cardiovascular and arteriothrombotic adverse events in chronic-phase CML patients after frontline TKIs

Cardiovascular or arteriothrombotic adverse events (CV- or AT-AEs) are reported in chronic myeloid leukemia (CML) patients treated with tyrosine kinase inhibitors (TKIs). The incidence and characteristics across different TKI have not been systematically analyzed. We analyzed 531 patients treated with frontline TKIs in different prospective trials: imatinib 400 mg (n = 71) and 800 mg (n = 203), nilotinib (n = 108), dasatinib (n = 106), and ponatinib (n = 43). Characteristics and incidence of new-onset CV-AEs and AT-AEs were analyzed. Poisson regression models assessed factors associated with AE incidence. Median follow-up was 94 months (range, 2-195). Overall, 237 patients (45%) developed CV-AEs and 46 (9%) developed AT-AEs. Hypertension was the most common AE seen in 175 patients (33%; grade 3/4 in 17%). CV-AE and AT-AE incidence ratios (IRs) with 95% confidence intervals (CIs) were 8.6 (7.6-9.8) and 1.7 (1.2-2.2) per 100 person-years. Among the TKIs, ponatinib showed the highest IR (95% CI) for CV-AEs and AT-AEs at 40.7 (27.9-59.4) and 9.0 (4.1-20.1). In multivariate analysis, ponatinib therapy was associated with increased incidence rate ratio (IRR) for CV-AEs (4.62; 95% CI, 2.7-7.7; P < .0001) and AT-AEs (6.38; 95% CI, 1.8-21.8; P < .0001) compared with imatinib 400. In summary, there is an increased risk of CV-AEs (except hypertension) and AT-AEs in CML patients treated with newer TKIs, particularly with ponatinib. Patients on TKIs must be informed and closely monitored for vascular AEs. These studies were registered at www.clinicaltrials.gov as #NCT00048672, #NCT00038649, #NCT00050531, #NCT00254423, #NCT00129740, and #NCT01570868.

Comparative Safety and Health Care Expenditures Among Patients With Chronic Myeloid Leukemia Initiating First-Line Imatinib, Dasatinib, or Nilotinib

PURPOSE

Tyrosine kinase inhibitors (TKIs) have dramatically improved survival for patients with chronic myeloid leukemia (CML). No overall survival differences were observed between patients initiating first- and second-generation TKIs in trials; however, real-world safety and cost outcomes are unclear. We evaluated comparative safety and health care expenditures between first-line imatinib, dasatinib, and nilotinib among patients with CML.

PATIENTS AND METHODS

Eligible patients had one or more fills for imatinib, dasatinib, or nilotinib in the MarketScan Commercial and Medicare Supplemental databases between January 1, 2011, and December 31, 2016 (earliest fill is the index date), 6 months pre-index continuous enrollment, CML diagnosis, and no TKI use in the pre-index period. Hospitalizations or emergency department visits (safety events) were compared across treatment groups using propensity-score-weighted 1-year relative risks (RRs) and subdistribution hazard ratios (HRs). Inflation-adjusted annual health care expenditures were compared using quantile regression.

RESULTS

Eligible patients included 1,417 receiving imatinib, 1,067 receiving dasatinib, and 647 receiving nilotinib. The 1-year risk of safety events was high: imatinib, 37%; dasatinib, 44%; and nilotinib, 40%, with higher risks among patients receiving dasatinib (RR, 1.17; 95% CI, 1.06 to 1.30) and nilotinib (RR, 1.07; 95% CI, 0.93 to 1.23) compared with those receiving imatinib. Over a median of 1.7 years, the cumulative incidence of safety events was higher among patients receiving dasatinib (HR, 1.23; 95% CI, 1.10 to 1.38) and nilotinib (HR, 1.08; 95% CI, 0.95 to 1.24) than among those receiving imatinib. One-year health care expenditures were high (median, $125,987) and were significantly higher among patients initiating second-generation TKIs compared with those receiving imatinib (difference in medians: dasatinib v imatinib, $22,393; 95% CI, $17,068 to $27,718; nilotinib v imatinib, $19,463; 95% CI, $14,689 to $24,236).

CONCLUSION

Patients receiving imatinib had the lowest risk of hospitalization or emergency department visits and 1-year health care expenditures. Given a lack of significant differences in overall survival, imatinib may represent the ideal first-line therapy for patients, on average.

EXPRESS: Pulmonary hypertension with dasatinib and other tyrosine kinase inhibitors

Dasatinib and other tyrosine kinase inhibitors are commonly utilized in the management of chronic myelogenous leukemia. Pulmonary hypertension is an important adverse event associated with dasatinib. Mechanisms for pulmonary hypertension include pulmonary endothelial injury, apoptosis, and increased susceptibility to other triggers for pulmonary hypertension. The diagnosis is suspected based on symptoms, suggested by echocardiographic findings, and confirmed with right heart catheterization. Management includes discontinuation of dasatinib and initiation of pulmonary vasodilators. Persistent pulmonary hypertension is present in up to one third of patients after cessation of dasatinib. Other tyrosine kinase inhibitors, including bosutinib, lapatinib, and ponatinib have also been implicated in pulmonary hypertension in small series, although evidence for causation is less robust. A high index of suspicion, continued vigilance for pulmonary hypertension with long-term use, and early therapy are important in optimizing outcomes in this population.

Inhibition of Src activation reverses pulmonary vascular remodeling in experimental pulmonary arterial hypertension via Akt/mTOR/HIF-1<alpha> signaling pathway

Pulmonary arterial hypertension (PAH) is a diffuse pulmonary microvascular remodeling disease accompanied by malignant proliferation of pulmonary artery smooth muscle cells (PASMCs), which causes persistent pulmonary artery pressure elevation, right ventricular hypertrophy (RVH) and death. However, current therapies targeting pulmonary vascular remodeling and RVH remain poorly effective in reversing PAH. Overactivation of the protein tyrosine kinase Src plays an important role in tumor cell growth, proliferation and invasion; we thus hypothesized that inhibitors targeting Src activation could reverse experimental PAH. We demonstrated that Src was markedly activated in hypoxia-stimulated PASMCs from donors and PASMCs isolated from PAH patients. We investigated the effects of the Src-selective inhibitor 1-(1,1-dimethylethyl)-1-(4-methylphenyl)-1H-pyrazolo[3,4-d]pyrimidin-4-amine (PP1) and berberine (BBR) on PAH-PASMC proliferation and migration by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU) and wound-healing assays. Our in vitro results showed that inhibition of Src (Tyr416) phosphorylation repressed PAH-PASMC proliferation and migration by inhibiting hypoxia-inducible factor-1α (HIF-1α) expression through Akt/mTOR signal pathway. In vivo, PP1 and BBR significantly alleviated distal pulmonary vascular remodeling and decreased right ventricular systolic pressure (RVSP) and RVH in Sugen (SU) 5416/hypoxia (SU-PAH) mice. These findings demonstrate that pharmacological (PP1 or BBR) inhibition of Src activation could be a novel means of treating severe pulmonary vascular remodeling and RVH in PAH patients.

[Efficacy and safety of domestic dasatinib as second-line treatment for chronic myeloid leukemia patients in the chronic phase]

Objective: To investigate the efficiency and safety of domestic tyrosine kinase inhibitor (TKI) dasatinib (Yinishu) as second-line treatment for patients with chronic myeloid leukemia in chronic phase (CML-CP). Methods: A retrospective analysis of clinical data of CML-CP patients who received domestic dasatinib as second-line treatment in the CML collaborative group hospitals of Hubei province from March 2016 to July 2018 was performed. The optimal response rate, the cumulative complete cytogenetic response (CCyR), the cumulative major molecular responses (MMR), progression free survival (PFS), event free survival (EFS) and adverse effects (AEs) of the patients were assessed at 3, 6 and 12 months of treatment. Results: A total of 83 CML-CP patients were enrolled in this study. The median follow-up time was 23 months. The optimal response rates at 3, 6 and 12 months in 83 CML-CP patients treated with dasatinib were 77.5% (54/71), 72.6% (61/75) and 60.7% (51/69), respectively. By the end of follow-up, the cumulative CCyR and MMR rates were 65.5% (55/80) and 57.1% (48/73), respectively. The median time to achieving CCyR and MMR was 3 months. During follow-up time, the PFS rate was 94.0% (79/83) and the EFS rate was 77.4% (65/83). The most common non-hematological AEs of dasatinib were edema (32.5%), rash itching (18.1%) and fatigue (13.3%). The common hematological AEs of dasatinib were thrombocytopenia (31.3%), leukopenia (19.3%) and anemia (6.0%). Conclusion: Domestic dasatinib was effective and safe as the second-line treatment of CML-CP patients and it can be used as an option for CML-CP patients.

Pleural adverse drugs reactions and protein kinase inhibitors: Identification of suspicious targets by disproportionality analysis from VigiBase

AIMS

To evaluate the risk of pleural disorders (PD) associated with 33 protein kinase (PK) inhibitors (PKIs) through a disproportionality analysis and to identify which PKs and pathways are involved in PKI-induced PD.

METHODS

To evaluate the risk of PD, reporting odds ratios (RORs) were calculated for 33 PKIs through data registered in the World Health Organization safety report database (VigiBase). We undertook a literature review to identify PKs that were possibly involved in PD caused by PKIs. Pearson correlation coefficients (r) between RORs and affinity data of 19 PKIs were calculated to identify the cellular target most likely to be involved in PKI-induced PD.

RESULTS

A total of 235 110 individual case safety reports were extracted from the database for 33 available PKIs. Among these reports, 5001 concerned PD (2.1%). Significant and positive disproportionality for PD was found for 29 of 33 PKI included in our study with top values for dasatinib [ROR = 115.3; 95% confidence interval (CI): 110.1-120.8], bosutinib (ROR = 20.4; 95% CI: 15.8-26.4) and ponatinib (ROR = 12; 95% CI: 9.2-15.6). Correlation analyses between the product of dissociation constant and ROR highlighted possibly Lyn involvement in PD with PKI (r = 0.73, P = 0.0004).

CONCLUSIONS

Our study showed that 28 of the 33 tested PKIs were associated with PD. Besides, the study highlighted the role of Lyn in PD caused by PKIs through an immune-mediated process.

Dasatinib-Induced Pulmonary Arterial Hypertension Treated with Upfront Combination Therapy

Pulmonary arterial hypertension (PAH) is a rare complication of dasatinib that was approved as a first-line therapy for chronic myelocytic leukemia (CML). A 24-year-old man presenting dyspnea at rest and leg edema was admitted to our hospital. He had been diagnosed with CML and prescribed dasatinib for 4 years. Chest X-ray showed significant bilateral pleural effusion and heart enlargement. Echocardiography revealed interventricular septal compression and elevated peak tricuspid regurgitation pressure gradient of 66.7 mmHg indicating severe pulmonary hypertension. After the other specific diseases to provoke PAH were excluded, he was diagnosed with dasatinib-induced PAH. Despite discontinuation of dasatinib and intravenous administration of diuretic for two weeks, World Health Organization (WHO) functional class was still II and mean pulmonary arterial pressure (PAP) was high at 37 mmHg. Therefore, we administered sildenafil and bosentan together as an upfront combination therapy three weeks after dasatinib discontinuation. Six months later, his symptoms improved to WHO functional class I and mean PAP was decreased to 31 mmHg. Although PAH is a rare complication of dasatinib, symptomatic patients prescribed with dasatinib should have an echocardiogram for PAH screening. Moreover, the upfront combination therapy would be a useful option for symptomatic patients after discontinuation of dasatinib.

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.

Pulmonary hypertension in patients with interstitial lung disease

Interstitial lung diseases (ILDs) comprise a broad and heterogeneous group of more than two hundred diseases with common functional characteristics. Their diagnosis and management require a multidisciplinary approach. This multidisciplinary approach involves the assessment of comorbid conditions including pulmonary hypertension (PH) that exerts a dramatic impact on survival. The current World Health Organization (WHO) classification of PH encompasses many of the interstitial lung diseases into WHO Group 3, while sarcoidosis, Pulmonary Langerhans Cell Histiocytosis and lymphangioleiomyomatosis are placed into WHO Group 5 as diseases with unclear or multifactorial mechanisms. Connective tissue diseases could span any of the 5 WHO groups based on the primary phenotype into which they manifest. Interestingly, several challenging phenotypes present with features that overlap between two or more WHO PH groups. Currently, PH-specific treatment is recommended only for patients classified into WHO Group 1 PH. The lack of specific treatment for other groups, including PH in the setting of ILD, reflects the poor outcomes of these patients. Thus, identification of the optimal strategy for ILD patients with PH remains an amenable need. This review article provides a brief overview of biomarkers indicative of vascular remodeling in interstitial lung disease, summarizes the current state of knowledge regarding patients with PH and ILD and highlights future perspectives that remain to be addressed.

Mitochondrial dysfunction and pulmonary hypertension: cause, effect, or both

Pulmonary hypertension describes a heterogeneous disease defined by increased pulmonary artery pressures, and progressive increase in pulmonary vascular resistance due to pathologic remodeling of the pulmonary vasculature involving pulmonary endothelial cells, pericytes, and smooth muscle cells. This process occurs under various conditions, and although these populations vary, the clinical manifestations are the same: progressive dyspnea, increases in right ventricular (RV) afterload and dysfunction, RV-pulmonary artery uncoupling, and right-sided heart failure with systemic circulatory collapse. The overall estimated 5-yr survival rate is 72% in highly functioning patients, and as low as 28% for those presenting with advanced symptoms. Metabolic theories have been suggested as underlying the pathogenesis of pulmonary hypertension with growing evidence of the role of mitochondrial dysfunction involving the major proteins of the electron transport chain, redox-related enzymes, regulators of the proton gradient and calcium homeostasis, regulators of apoptosis, and mitophagy. There remain more studies needed to characterize mitochondrial dysfunction leading to impaired vascular relaxation, increase proliferation, and failure of regulatory mechanisms. The effects on endothelial cells and resulting interactions with their microenvironment remain uncharted territory for future discovery. Additionally, on the basis of observations that the "plexigenic lesions" of pulmonary hypertension resemble the unregulated proliferation of tumor cells, similarities between cancer pathobiology and pulmonary hypertension have been drawn, suggesting interactions between mitochondria and angiogenesis. Recently, mitochondria targeting has become feasible, which may yield new therapeutic strategies. We present a state-of-the-art review of the role of mitochondria in both the pathobiology of pulmonary hypertension and potential therapeutic targets in pulmonary vascular processes.

Combination targeted pulmonary hypertension therapy in the resolution of Dasatinib-associated pulmonary arterial hypertension

Dasatinib is a small-molecule tyrosine kinase inhibitor used in the treatment of hematological malignancies. Pulmonary arterial hypertension (PAH) is a rare but known complication. The mainstay of treatment is cessation of Dasatinib, and while clinical improvement is rapid, complete hemodynamic resolution of pulmonary hypertension (PH) still remains exceedingly uncommon. We present a case of Dasatinib-induced PAH in a woman with chronic myeloid leukemia, who demonstrated rapid and complete clinical and hemodynamic resolution following treatment with combination pulmonary vasodilator therapy using an endothelin receptor antagonist and a phosphodiesterase-5 inhibitor. This case suggests there may be an association between the use of targeted PH medication in combination and the complete resolution of dasatinib-associated PAH, but further investigation is required.