[IMATINIB INDUCED EDEMA].

INTRODUCTION: Imatinib is a tyrosine kinase inhibitor and is used for the treatment of chronic myeloid leukemia (CML) since 2002. We present a patient who suffered from fluid retention and periorbital edema secondary to this drug.

[Side effects of dermato-oncologic therapies]. / Nebenwirkungen dermatoonkologischer Therapien.

BACKGROUND: Immune checkpoint inhibitors (ICIs) such as PD(L)1 and CTLA4 antibodies as well as targeted therapies such as BRAF and MEK inhibitors have significantly improved the systemic treatment of skin cancer in adjuvant and advanced therapy settings. All these drugs differ in their spectrum of side effects. MATERIALS AND METHODS: The aim of this article is to provide an overview of the spectrum of side effects of dermato-oncological therapies and their management, taking into account the current literature. RESULTS: The most important side effects of ICIs, the CCR4 inhibitor mogamulizumab, the ImmTAC tebentafusp, the BRAF and MEK inhibitors and the multityrosine kinase inhibitor imatinib are considered. CONCLUSIONS: Side effects can manifest themselves in all organ systems. Chronic side effects and long-term harm are possible, especially with ICIs, and require close therapy monitoring and patient education. Knowledge of the side effects and the temporal, sometimes delayed course of their occurrence are essential for diagnosis and prompt initiation of therapy.

Ponatinib vs Imatinib in Frontline Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia: A Randomized Clinical Trial.

Importance: In newly diagnosed Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL), disease progression due to acquired resistance to first- or second-generation BCR::ABL1 tyrosine kinase inhibitors is common. Ponatinib inhibits BCR::ABL1 and all single-mutation variants, including T315I. Objective: To compare frontline ponatinib vs imatinib in adults with newly diagnosed Ph+ ALL. Design, Setting, and Participants: Global registrational, phase 3, open-label trial in adults aged 18 years or older with newly diagnosed Ph+ ALL. From January 2019 to May 2022, eligible patients at 77 sites were randomized 2:1 to ponatinib (30 mg/d) or imatinib (600 mg/d) with reduced-intensity chemotherapy, followed by single-agent ponatinib or imatinib after the cycle 20 phase of the trial. The last date of follow-up for this analysis was August 12, 2022. Intervention: Patients received ponatinib, 30 mg/d, or imatinib, 600 mg/d, with reduced-intensity chemotherapy, followed by single-agent ponatinib or imatinib after cycle 20. The ponatinib dose was reduced to 15 mg on achievement of minimal residual disease-(MRD) negative complete remission. Main Outcomes and Measures: The primary end point of this interim analysis was MRD-negative complete remission (≤0.01% BCR::ABL1 [MR4] centrally assessed by reverse transcriptase-quantitative polymerase chain reaction), with complete remission maintained for at least 4 weeks at the end of cycle 3. The key secondary end point was event-free survival. Results: Of 245 patients randomized (median age, 54 years; 133 [54.3%] female), 232 (ponatinib, n = 154; imatinib, n = 78) who had p190 or p210 dominant isoforms verified by the central laboratory were analyzed for the primary end point. The MRD-negative complete remission rate (primary end point) was significantly higher with ponatinib (34.4% [53/154]) vs imatinib (16.7% [13/78]) (risk difference, 0.18 [95% CI, 0.06-0.29]; P = .002). At the data cutoff, event-free survival had not met the prespecified number of events. Median event-free survival was not reached in the ponatinib group and was 29 months in the imatinib group. The most common adverse events were similar between treatment groups. Arterial occlusive events were infrequent and comparable between groups (ponatinib, 2.5%; imatinib, 1.2%). Conclusions and Relevance: Ponatinib demonstrated a superior rate of MRD-negative complete remission at the end of induction vs imatinib when combined with reduced-intensity chemotherapy in adults with newly diagnosed Ph+ ALL. The safety profile of ponatinib was comparable with imatinib. Trial Registration: ClinicalTrials.gov Identifier: NCT03589326.

Imatinib-induced dermatomyositis sine dermatitis - a rare case report.

Idiopathic Inflammatory Myopathies are rare conditions with several heterogeneous disease subtypes. They can range from limited muscle or skin involvement to severe, systemic, life-threatening disease. Although the etiology is unknown, some evidence suggests a role for external agents, particularly drugs. Herein, we present a case of a 71-year-old woman with chronic myeloid leukemia who developed imatinib-induced dermatomyositis sine dermatitis. The presentation was predominantly muscular, characterized by proximal muscle weakness and myalgia of the lower limbs, with positive anti-Mi2a antibodies. Spontaneous recovery was observed after drug discontinuation, without the need for immunosuppressive therapy. This is the first confirmed description of an imatinib-induced dermatomyositis sine dermatitis. It reflects the importance of a high awareness from rheumatologists and hematologists to accurately anticipate and identify similar situations.

A case-matched study of imatinib mesylate between different formulations on plasma trough concentration, adverse events, quality of life and outcomes in gastrointestinal stromal tumor patients.

Genike, the imatinib (IM)-alpha form is widely used in the treatment of gastrointestinal stromal tumor (GIST) patients in China. We wanted to investigate whether there are differences in IM plasma concentrations, adverse events, health-related quality of life (QOL) and outcomes between patients treated with Genike and Glivec. Thirty included GIST patients receiving IM treatment were matched to either Genike or Glivec according to gastrectomy, body weight, body surface area and sex. There was no statistically significant difference in IM trough plasma levels between the two groups. There were no significant differences in very common adverse events of IM between the Genike and Glivec groups. IM was well tolerated, although it was associated with a significant change in cognitive function (P < 0.001), fatigue (P = 0.015), pain (P = 0.015), nausea/vomiting (P = 0.029), insomnia (P = 0.019), diarrhea (P = 0.003) and financial difficulties (P < 0.001). Physical functioning, financial burden and insomnia were significantly different between the two groups (P = 0.026). Until Aug. 2022, there was no significant difference in time to imatinib treatment failure (TTF) between the two groups. In conclusion, there was no difference in IM plasma concentration and adverse events between Genike and Glivec. Both Genike and Glivec could partially decrease the QOL of GIST patients. Physical functioning was worse in Genike group than in Glivec group, while the economic burden and symptoms of insomnia in Glivec patients were worse. There was no significant difference in TTF between the two groups.

Clinical and Biomarker Analysis of a Phase I/II Study of PDR001 Plus Imatinib for Advanced Treatment-Refractory Gastrointestinal Stromal Tumors.

PURPOSE: In this phase Ib/II study, we aimed to evaluate the safety and efficacy of PDR001, an anti-PD1 antibody, in combination with imatinib in patients with treatment-refractory gastrointestinal stromal tumor (GIST). PATIENTS AND METHODS: Patients with advanced GIST whose disease had progressed on imatinib, sunitinib, and regorafenib were enrolled. In phase Ib, the standard 3 + 3 dose escalation scheme was applied. Intravenous administration of PDR001 at 400 mg for every 4 weeks plus imatinib (300 and 400 mg daily for dose levels I and II, respectively) was given. The primary outcome for phase II was the disease control rate at 12 weeks. Exploratory biomarker analysis was performed based on PDL1 IHC, next-generation sequencing, and multiplexed IHC. RESULTS: No dose-limiting toxicity was observed in the phase Ib part (n = 10), and dose level II was selected as the recommended phase II dose. In the phase II part (n = 29), there was no objective response, and the disease control rate at 12 weeks was 37.9%, not meeting the primary efficacy endpoint. For patients in phase Ib-dose level II and phase II (n = 36), the median progression-free survival (PFS) and overall survival were 2.3 and 9.5 months, respectively. The most common grade 3 to 4 adverse event was anemia. Exploratory biomarker analysis indicated that a higher CD8+ T-cell density was associated with a favorable PFS but to a limited degree. Tumor mutational burden and PDL1 were not associated with better PFS. CONCLUSIONS: In patients with treatment-refractory GIST, PDR001 in combination with imatinib was generally tolerable, but it was not effective.

The correlation of sarcopenia and adverse events of imatinib therapy postoperatively in gastrointestinal stromal tumor through computed tomography quantitative body composition.

PURPOSE: This study aimed to investigate the correlation between sarcopenia and adverse events (AEs) of postoperative imatinib therapy through computed tomography (CT) quantitative body composition for intermediate- and high-risk gastrointestinal stromal tumors (GISTs). METHODS: The study retrospectively analyzed the clinical data of 208 patients with intermediate- and high-risk GIST treated surgically and treated with imatinib afterward at the First Affiliated Hospital of Wenzhou Medical University between October 2011 and October 2021. Images of preoperative CT scans within 1 month were used to determine the body composition of the patients. On the basis of the L3 skeletal muscle index, patients were classified into sarcopenia and nonsarcopenia groups. In 2 groups, AEs related to imatinib were analyzed. RESULTS: The proportion of AEs related to imatinib in the sarcopenia group was higher, and this disparity had a significant statistical significance (P = .013). Sarcopenia was significantly associated with hemoglobin reduction compared with nonsarcopenia (P = .015). There was a significant difference between the sarcopenia group and the nonsarcopenia group in the ratio of severe AEs (grades 3-4). Hemoglobin content (odds ratio [OR], 0.981; 95% CI, 0.963-1.000; P = .045), sex (OR, 0.416; 95% CI, 0.192-0.904; P = .027), and sarcopenia (OR, 5.631; 95% CI, 2.262-14.014; P < .001) were the influential factors of imatinib severe AEs in patients with intermediate- and high-risk GIST within 1 year after imatinib treatment. CONCLUSION: Patients with preoperative sarcopenia have a higher incidence and severity of AEs during adjuvant imatinib therapy.

Oral arsenic plus imatinib versus imatinib solely for newly diagnosed chronic myeloid leukemia: a randomized phase 3 trial with 5-year outcomes.

PURPOSE: The synergistic effects of combining arsenic compounds with imatinib against chronic myeloid leukemia (CML) have been established using in vitro data. We conducted a clinical trial to compare the efficacy of the arsenic realgar-indigo naturalis formula (RIF) plus imatinib with that of imatinib monotherapy in patients with newly diagnosed chronic phase CML (CP-CML). METHODS: In this multicenter, randomized, double-blind, phase 3 trial, 191 outpatients with newly diagnosed CP-CML were randomly assigned to receive oral RIF plus imatinib (n = 96) or placebo plus imatinib (n = 95). The primary end point was the major molecular response (MMR) at 6 months. Secondary end points include molecular response 4 (MR4), molecular response 4.5 (MR4.5), progression-free survival (PFS), overall survival (OS), and adverse events. RESULTS: The median follow-up duration was 51 months. Due to the COVID-19 pandemic, the recruitment to this study had to be terminated early, on May 28, 2020. The rates of MMR had no significant statistical difference between combination and imatinib arms at 6 months and any other time during the trial. MR4 rates were similar in both arms. However, the 12-month cumulative rates of MR4.5 in the combination and imatinib arms were 20.8% and 10.5%, respectively (p = 0.043). In core treatment since the 2-year analysis, the frequency of MR4.5 was 55.6% in the combination arm and 38.6% in the imatinib arm (p = 0.063). PFS and OS were similar at five years. The safety profiles were similar and serious adverse events were uncommon in both groups. CONCLUSION: The results of imatinib plus RIF as a first-line treatment of CP-CML compared with imatinib might be more effective for achieving a deeper molecular response (Chinadrugtrials number, CTR20170221).

Incidence of pleural effusion with dasatinib and the effect of switching therapy to a different TKI in patients with chronic phase CML.

Dasatinib is one of the second generation tyrosine kinase inhibitors (TKI) which is approved for the treatment of patients with chronic phase CML (CP-CML) both in the front line and in the second line setting. Pleural effusion (PE) is a unique toxicity associated with dasatinib use. Our aim was to study the incidence of pleural effusion in our cohort of patients who were treated with dasatinib for CP-CML and the safety upon TKI switch. A total of 390 patients were treated with dasatinib during their course of treatment for CP-CML. A total of 69 patients (17.6%) developed any grade of PE. About 33 (48%) patients developed CTCAE grade 2 PE, 34 (49%) grade 3 and only 1 patient developed grade 4 PE. Recurrence of PE was observed in 34 (49%) patients. While only 12 patients (17.3%) continued using dasatinib after development of PE, dasatinib was discontinued in the other 57 patients. Therapy was switched to bosutinib in 13 patients out of which 6 (46%) patients re-developed PE. While only 12.5% patients developed re-accumulation of pleural fluid in patients switched to imatinib, none of the patients switched to nilotinib re-developed PE. A change in TKI to bosutinib was associated with a 46% risk of recurrence of PE in patients who develop PE on dasatinib for the treatment of CP-CML. The incidence of recurrent PE was markedly lower in patient switched to imatinib or nilotinib.

A safety review of tyrosine kinase inhibitors for chronic myeloid leukemia.

INTRODUCTION: Since the introduction of first tyrosine kinase inhibitor (TKI) imatinib, the treatment of chronic myeloid leukemia (CML) has reached excellent survival expectancies. Long survival rates bring about issues regarding TKI safety. AREAS COVERED: The aim of this review is to compare the side effects of current TKIs both in the first and later lines and outline a safety andprofile of CML treatment. Seminal studies on TKIs and other newer drugs and extended follow-up of these studies; real-life data of each drug were usedduring the course of this. PubMed was used as a search database and onlyarticles in English were included. EXPERT OPINION: With longer follow-up CML patients, resistant slowgrade adverse events seem to be the major obstacle in the way of treatmentefficacy. If efficacy is the priority, vigorous treatment of side effect and administration of full dose TKI are reasonable. But when treatment goals are reached, dose modifications or alternative treatment regimens may be acceptedpossible. More studies are needed on dose modification protocols and potential benefits and safety of treatment-free remission.

Efficacy and safety of bosutinib in patients treated with prior imatinib and/or dasatinib and/or nilotinib: Subgroup analyses from the phase 4 BYOND study.

The BYOND study evaluated the efficacy and safety of bosutinib 500 mg once daily in patients with chronic myeloid leukemia (CML) resistant/intolerant to prior tyrosine kinase inhibitors (TKIs). These post-hoc analyses assessed the efficacy and safety of bosutinib by resistance or intolerance to prior TKIs (imatinib-resistant vs dasatinib/nilotinib-resistant vs TKI-intolerant), and cross-intolerance between bosutinib and prior TKIs (imatinib, dasatinib, nilotinib), in patients with Philadelphia chromosome-positive chronic phase CML. Data are reported after ≥3 years' follow-up. Of 156 patients with Philadelphia chromosome-positive chronic phase CML, 53 were imatinib-resistant, 29 dasatinib/nilotinib-resistant, and 74 intolerant to all prior TKIs; cumulative complete cytogenetic response rates at any time were 83.7%, 61.5%, and 86.8%, and cumulative major molecular response rates at any time were 72.9%, 40.7%, and 82.4%, respectively. Of 141, 95, and 79 patients who received prior imatinib, dasatinib, and nilotinib, 64 (45.4%), 71 (74.7%), and 60 (75.9%) discontinued the respective TKI due to intolerance; of these, 2 (3.1%), 5 (7.0%), and 0 had cross-intolerance with bosutinib. The response rates observed in TKI-resistant and TKI-intolerant patients, and low cross-intolerance between bosutinib and prior TKIs, further support bosutinib use for patients with Philadelphia chromosome-positive chronic phase CML resistant/intolerant to prior TKIs. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02228382.

Therapeutic drug monitoring of imatinib - how far are we in the leukemia setting?

INTRODUCTION: Tyrosine kinase inhibitors (TKIs) have revolutionized survival rates of chronic myeloid leukemia (CML) and Philadelphia chromosome positive (Ph+) acute lymphoblastic leukemia (ALL) and replaced hematopoietic stem cell transplantation (hSCT) as the key treatment option for these patients. More recently, the so-called Philadelphia chromosome-like (Ph-like) ALL has similarly benefitted from TKIs. However, many patients shift from the first generation TKI, imatinib, due to treatment-related toxicities or lack of treatment efficacy. A more personalized approach to TKI treatment could counteract these challenges and potentially be more cost-effective. Therapeutic drug monitoring (TDM) has led to higher response rates and less treatment-related toxicity in adult CML but is rarely used in ALL or in childhood CML. AREAS COVERED: This review summarizes different antileukemic treatment indications for TKIs with focus on imatinib and its pharmacokinetic/-dynamic properties as well as opportunities and pitfalls of TDM for imatinib treatment in relation to pharmacogenetics and co-medication for pediatric and adult Ph+/Ph-like leukemias. EXPERT OPINION: TDM of imatinib adds value to standard monitoring of ABL-class leukemia by uncovering non-adherence and potentially mitigating adverse effects. Clinically implementable pharmacokinetic/-dynamic models adjusted for relevant pharmacogenetics could improve individual dosing. Prospective trials of TDM-based treatments, including both children and adults, are needed.

Resolution of gastric antral vascular ectasia following cessation of imatinib.

A female patient in her 80s presented with chronic iron-deficiency anaemia secondary to gastric antral vascular ectasia (GAVE), despite repeated endoscopic treatment. Her medical history was notable for chronic myeloid leukaemia, for which she took imatinib. Due to a possible association between imatinib and GAVE described in a small number of case reports, cessation of imatinib was trialled. This led to a significant improvement in the patient's anaemia and resolution of GAVE on repeat endoscopy. GAVE is an uncommon cause of gastrointestinal bleeding, the aetiology of which is uncertain. This report describes an approach to the differential diagnosis of chronic iron-deficiency anaemia and an overview of GAVE syndrome. It illustrates the benefit of broadening the differential when the diagnosis is uncertain and the utility of case reports in informing the differential diagnosis.

Maximizing the Value of Chronic Myeloid Leukemia Management Using Tyrosine Kinase Inhibitors in the USA: Potential Determinants and Consequences of Healthcare Resource Utilization and Costs, with Proposed Optimization Approaches.

BACKGROUND AND OBJECTIVES: The introduction and widespread use of effective and well-tolerated tyrosine kinase inhibitors for chronic myeloid leukemia have been associated with marked increments in life expectancy and disease prevalence. These changes have been accompanied by elevations in costs of tyrosine kinase inhibitors, which typically must be taken ad vitam after diagnosis and tend to be more expensive than medical therapies for many other hematologic malignancies. The aims of this review included evaluating the potential associations and consequences of healthcare resource utilization and costs of tyrosine kinase inhibitors and possible clinical management approaches to mitigate them. METHODS: A PubMed search of English-language US study reports was conducted that covered the interval of 2001 (US approval of imatinib) through 17 April, 2023 augmented by manual reviews of published bibliographies from the referenced articles and searches of other databases: Google Scholar and Scopus. RESULTS: On the basis of this analysis of chiefly real-world evidence (administrative claims database studies), healthcare resource utilization and costs can be considered indicators of ineffective chronic myeloid leukemia management, including potentially mutation-driven treatment resistance and costly tyrosine kinase inhibitor switches, non-adherence, and suboptimal tolerability, which may culminate in the progression of disease from the chronic to an accelerated or blast phase, with additional excess costs. Costs of tyrosine kinase inhibitors are also associated with reduced treatment adherence. At a willingness-to-pay threshold of $50,000-$200,000 per quality-adjusted life-year, tyrosine kinase inhibitors can be considered cost effective from a US payer perspective. Potential clinical approaches to mitigate costs include regular molecular monitoring with proactive assessments of BCR::ABL1 gene mutations to avoid costly treatment switches, as well as interventions to enhance treatment adherence and tyrosine kinase inhibitor tolerability. CONCLUSIONS: Healthcare resource utilization and costs of chronic myeloid leukemia care may be considered barometers of ineffective management, including mutation-driven tyrosine kinase inhibitor resistance and switching as well as non-adherence and intolerance. Future prospective research is warranted to help determine whether costs can be reduced and other treatment outcomes optimized via more proactive and effective diagnostic interventions (i.e., regular molecular monitoring and proactive mutational testing) and treatment approaches. The strengths and limitations of this review include its emphasis on observational research, which, on one hand, offers a naturalistic "real-world" perspective on current chronic myeloid leukemia management, but, on the other hand, is associational in nature and cannot be used to determine causality and/or its direction.

Second Treatment-Free Remission Attempt in Patients with Chronic Myeloid Leukemia.

Long-term survival outcomes of patients with chronic myeloid leukemia in the chronic phase are now similar to those of the general population, following the introduction of ABL1 tyrosine kinase inhibitors (TKIs). Approximately 40% to 80% of patients with chronic myeloid leukemia successfully achieved treatment-free remission after the first attempt of TKI discontinuation (TFR1), after achieving a durable deep molecular response. However, the possibility of achieving treatment-free remission after a second attempt of TKI discontinuation (TFR2) remains unclear. Therefore, we reviewed current TFR2 studies to clarify the feasibility of achieving TFR2. We identified 5 TFR2 clinical trials and 2 real-world reports. TFR2 attempt may be feasible after retreatment with imatinib, nilotinib, or dasatinib. Patients who have achieved MR4.0 or deeper durable molecular remission are eligible to enter the TFR2 phase. Imatinib is well tolerated and can be administered for consolidative treatment before the TFR2 attempt, whereas drug-related adverse effects of nilotinib or dasatinib affect their tolerability and might lead to discontinuation. Late onset relapse (> 1 year or > 2 year) was often reported, thus careful monitoring is needed.

Correlation Between N-Demethyl Imatinib Trough Concentration and Serious Adverse Reactions in Patients with Gastrointestinal Stromal Tumors: A Retrospective Cohort Study.

BACKGROUND: Imatinib is the first-line treatment for gastrointestinal stromal tumors; however, the clinical prognosis and adverse reactions of patients vary owing to individualized discrepancies in plasma exposure. METHODS: To determine the safe interval for steady-state plasma trough concentrations (C min ) of imatinib and its active metabolite, N-demethyl imatinib (NDI), 328 plasma samples from 273 patients treated with imatinib were retrospectively analyzed. Imatinib C min and NDI C min were tested, and adverse reactions were recorded. The association between imatinib C min , NDI C min , and serious adverse reactions was evaluated. RESULTS: The C min range of imatinib was 209.5-4950.0 ng/mL, with the mean value and SD of 1491.8 ± 731.4 ng/mL. The C min range of NDI was 80.0-2390.0 ng/mL with the mean value and SD of 610.8 ± 281.5 ng/mL. NDI C min was positively correlated with imatinib C min , whereas the ratio of NDI C min to imatinib C min (NDI C min /imatinib C min ) was negatively correlated with imatinib C min . Univariate logistic regression analysis demonstrated that the treatment objective, daily dose, imatinib C min , NDI C min , and imatinib C min + NDI C min were significantly associated with serious adverse reactions. Multivariate logistic regression analysis showed that NDI C min was an independent risk factor for serious adverse reactions, with a threshold of 665 ng/mL. CONCLUSIONS: NDI C min was an independent risk factor for serious adverse reactions, with a threshold of 665 ng/mL. Monitoring NDI C min was beneficial for the rational application of imatinib and individualized treatment of patients with gastrointestinal stromal tumors.

The prevalence of hepatic and thyroid toxicity associated with imatinib treatment of chronic myeloid leukaemia: a systematic review.

BACKGROUND: Imatinib, a potent inhibitor of targeted protein tyrosine kinases, treats chronic myeloid leukaemia (CML). Data on imatinib-associated changes in hepatic and thyroid functions are limited and conflicting. AIM: To report the prevalence of hepatic and thyroid toxicity associated with the use of imatinib in CML patients. METHOD: Articles for the systematic review were selected from electronic databases (PubMed, CINALH, Web of Science). Readily accessible peer-reviewed full articles in English published 1st January 2000 to 18th July 2023 were included. The search terms included combinations of: imatinib, CML, liver toxicity, hepatic toxicity, thyroid toxicity. Screening of titles, abstracts, full text articles was conducted independently by two reviewers. Inclusions and exclusions were recorded following PRISMA guidelines. Detailed reasons for exclusion were recorded. Included articles were critically appraised. RESULTS: Ten thousand one hundred and twenty-three CML patients were reported in the 82 included studies corresponding to 21 case reports, 2 case series, 39 clinical trials and 20 observational studies were selected. Excluding case studies/reports, 1268 (12.6%; n = 1268/10046) hepatotoxicity adverse events were reported, of which 64.7% were rated as mild grade I & II adverse events, 363 (28.6%) as severe, grade III and IV adverse events; some led to treatment discontinuation, liver transplantation and fatal consequences. Twenty (35.1%) studies reported discontinuation of imatinib treatment due to the severity of hepatic toxicity. Fourteen (8.4%, n = 14/167) thyroid dysfunction adverse events were reported. CONCLUSION: High frequency of mild and severe hepatotoxicity, associated with imatinib in CML patients, was reported in the published literature. Low numbers of mild and manageable thyroid toxicity events were reported.

Individualized Dosing Patterns in the Treatment of Older Patients with Gastrointestinal Stromal Tumors: Results of a Registry-Based Observational National Cohort Study Including 871 Patients.

BACKGROUND: While the effectiveness of tyrosine kinase inhibitors (TKIs) seems similar in older patients with gastrointestinal stromal tumors (GIST) compared with younger patients, toxicities in older patients treated with TKIs more often lead to discontinuation of treatment. OBJECTIVE: To better understand the age-related pharmacology and pharmacodynamic differences in patients with GIST treated with TKIs, the primary aim of this study was to evaluate TKI dosing patterns in older patients with GIST, while the secondary aims were to evaluate differences in imatinib trough plasma concentrations between age groups and to compare the overall survival (OS) in patients with and without dose reductions in all treatment lines in a palliative setting. METHODS: Patients (18 years of age or older) with histologically proven GIST diagnosed between January 2009 and June 2021 and treated with one or more lines of TKIs were selected from the Dutch GIST Registry (DGR) database. Age groups were divided into younger patients (age <70 years) and older patients (age ≥70 years). All imatinib trough plasma concentrations of blood withdrawals taken from initiation of imatinib until a maximum of 1 year of treatment with imatinib were collected. Reasons for first adjustment of treatment were classified as adverse event, dose modification, progressive disease and other reasons. The next treatment steps after first adjustment of treatment were defined as dose escalation, dose reduction, dose interruption, or end of treatment. The association of dose reduction and OS was analyzed using the landmark approach. RESULTS: Overall, 871 patients were included in this study, including 577 younger patients and 294 older patients. Older patients more often had an adverse event as the reason for first adjustment of treatment with both imatinib (45.6%; p < 0.001) and sunitinib (58.6%; p = 0.224) compared with younger patients (19.5% and 42.7%, respectively). Adjustment of imatinib and sunitinib after starting on a standard dose because of an adverse event most often resulted in dose reduction in both age groups. Median trough plasma concentrations of all samples taken within the first year after initiation of imatinib were higher in older patients (1228 ng/mL, interquartile range [IQR] 959-1687) compared with younger patients (1035 ng/mL [IQR 773-1377]; p < 0.001). No significant differences were seen between OS in patients with or without dose reduction in all treatment lines (imatinib: p = 0.270; sunitinib: p = 0.547; and regorafenib: p = 0.784). CONCLUSION: Older patients showed higher imatinib trough plasma concentrations compared with younger patients and also had earlier and more often adverse events as the reason for first adjustment of treatment with imatinib followed by dose reduction. However, in a landmark analysis, patients with imatinib dose reductions had no poorer outcomes compared with patients not requiring a dose reduction.

[To compare the efficacy and incidence of severe hematological adverse events of flumatinib and imatinib in patients newly diagnosed with chronic phase chronic myeloid leukemia].

Objective: To analyze and compare therapy responses, outcomes, and incidence of severe hematologic adverse events of flumatinib and imatinib in patients newly diagnosed with chronic phase chronic myeloid leukemia (CML) . Methods: Data of patients with chronic phase CML diagnosed between January 2006 and November 2022 from 76 centers, aged ≥18 years, and received initial flumatinib or imatinib therapy within 6 months after diagnosis in China were retrospectively interrogated. Propensity score matching (PSM) analysis was performed to reduce the bias of the initial TKI selection, and the therapy responses and outcomes of patients receiving initial flumatinib or imatinib therapy were compared. Results: A total of 4 833 adult patients with CML receiving initial imatinib (n=4 380) or flumatinib (n=453) therapy were included in the study. In the imatinib cohort, the median follow-up time was 54 [interquartile range (IQR), 31-85] months, and the 7-year cumulative incidences of CCyR, MMR, MR(4), and MR(4.5) were 95.2%, 88.4%, 78.3%, and 63.0%, respectively. The 7-year FFS, PFS, and OS rates were 71.8%, 93.0%, and 96.9%, respectively. With the median follow-up of 18 (IQR, 13-25) months in the flumatinib cohort, the 2-year cumulative incidences of CCyR, MMR, MR(4), and MR(4.5) were 95.4%, 86.5%, 58.4%, and 46.6%, respectively. The 2-year FFS, PFS, and OS rates were 80.1%, 95.0%, and 99.5%, respectively. The PSM analysis indicated that patients receiving initial flumatinib therapy had significantly higher cumulative incidences of CCyR, MMR, MR(4), and MR(4.5) and higher probabilities of FFS than those receiving the initial imatinib therapy (all P<0.001), whereas the PFS (P=0.230) and OS (P=0.268) were comparable between the two cohorts. The incidence of severe hematologic adverse events (grade≥Ⅲ) was comparable in the two cohorts. Conclusion: Patients receiving initial flumatinib therapy had higher cumulative incidences of therapy responses and higher probability of FFS than those receiving initial imatinib therapy, whereas the incidence of severe hematologic adverse events was comparable between the two cohorts.