Relative Factors Analysis of Imatinib Trough Concentration in Chinese Patients with Gastrointestinal Stromal Tumor

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.

Development of a simultaneous quantification method of imatinib and sunitinib and their main metabolites and its application in patients with gastrointestinal stromal tumor

Correlations between plasma concentrations of imatinib and sunitinib with efficacy and toxicity have been established. It is crucial to develop a sensitive and precise method for determining the plasma concentrations of imatinib and sunitinib, along with their active metabolites, to facilitate therapeutic drug monitoring and individualized therapy. Plasma samples were separated on an Agilent ZORBAX SB-C18 chromatographic column using gradient elution. Quantification was performed using a mass spectrometer equipped with electrospray ionization in multiple reaction monitoring. The analysis time was 18 min per run, with all analytes and internal standards eluting within 8 min. The calibration range was 25-4000 ng/mL for imatinib, 5-800 ng/mL for N-desmethyl imatinib (CGP74588), and 2.5-400 ng/mL for sunitinib and N-desethyl sunitinib (SU12662). Intra- and inter-assay precision were both below 15%, and accuracy ranged between 90.0% and 101.9%. The method was successfully applied to determine blood samples from 120 patients with gastrointestinal stromal tumors who received imatinib (n = 115) and sunitinib (n = 5). It has been validated as linear, accurate, precise, and robust, making it suitable for therapeutic drug monitoring of imatinib and sunitinib in routine clinical practice.

Advanced gastrointestinal stromal tumor: reliable classification of imatinib plasma trough concentration via machine learning

AIM

Patients with advanced gastrointestinal stromal tumors (GISTs) exhibiting an imatinib plasma trough concentration (IM Cmin) under 1100 ng/ml may show a reduced drug response rate, leading to the suggestion of monitoring for IM Cmin. Consequently, the objective of this research was to create a customized IM Cmin classification model for patients with advanced GISTs from China.

METHODS

Initial data and laboratory indicators from patients with advanced GISTs were gathered, and the above information was segmented into a training set, validation set, and testing set in a 6:2:2 ratio. Key variables associated with IM Cmin were identified to construct the classification model using the least absolute shrinkage and selection operator (LASSO) regression and forward stepwise binary logistic regression. Within the training and validation sets, nine ML classification models were constructed via the resampling method and underwent comparison through the Brier scores, the areas under the receiver-operating characteristic curve (AUROC), the decision curve, and the precision-recall (AUPR) curve to determine the most suitable model for this dataset. Two methods of internal validation were used to assess the most suitable model's classification performance: tenfold cross-validation and random split-sample validation (test set), and the value of the test set AUROC was used to evaluate the model's classification performance.

RESULTS

Six key variables (gender, daily IM dose, metastatic site, red blood cell count, platelet count, and percentage of neutrophils) were ultimately selected to construct the classification model. In the validation set, it is found by comparison that the Extreme Gradient Boosting (XGBoost) model has the largest AUROC, the lowest Brier score, the largest area under the decision curve, and the largest AUPR value. Furthermore, as evaluated via internal verification, it also performed well in the test set (AUROC = 0.725).

CONCLUSION

For patients with advanced GISTs who receive IM, initial data and laboratory indicators could be used to accurately estimate whether the IM Cmin is below 1100 ng/ml. The XGBoost model may stand a chance to assist clinicians in directing the administration of IM.

Plasma trough concentration of imatinib and its effect on therapeutic efficacy and adverse events in Japanese patients with GIST

BACKGROUND

Imatinib mesylate (IM) is the standard chemotherapy for patients with gastrointestinal stromal tumors (GISTs) and has a favorable safety profile. Pharmacokinetics (PK), such as plasma trough concentration (Cmin), varies among patients, requiring the need for therapeutic drug monitoring (TDM) during IM administration. Despite some reports from overseas, the relationship between Cmin, adverse events (AEs), and treatment efficacy in Japanese patients with GIST has still been lacking. This study aimed to investigate the relationship between IM plasma concentration and AEs in Japanese patients with GISTs.

METHODS

This retrospective study analyzed the data of 83 patients who underwent IM treatment for GISTs at our institution between May 2002 and September 2021.

RESULTS

The IM Cmin was associated with any grade of AEs (with AEs vs. without AEs = 1294 (260-4075) vs. 857 (163-1886) ng/mL, P < 0.001), edema (with edema vs. without edema = 1278 (634-4075) vs. 1036 (163-4069) ng/mL, P = 0.017), and fatigue (with fatigue vs. without fatigue = 1373 (634-4069) vs. 1046 (163-4075) ng/mL, P = 0.044). Moreover, a Cmin ≥ 1283 ng/mL was a risk factor for severe AEs. The median progression-free survival (PFS) was 3.04 years in the lowest Cmin tertile (T1, < 917 ng/mL) compared with 5.90 years for T2 and T3 (P = 0.010).

CONCLUSION

Edema and fatigue are potentially associated with IM plasma trough concentrations of ≥ 1283 ng/mL in Japanese patients with GISTs. Further, maintaining an IM plasma trough concentration above 917 ng/mL may improve PFS.

The Application of Virtual Therapeutic Drug Monitoring to Assess the Pharmacokinetics of Imatinib in a Chinese Cancer Population Group

PURPOSE

Imatinib is used in gastrointestinal stromal tumours (GIST) and chronic myeloid leukaemia (CML). Oncology patients demonstrate altered physiology compared to healthy adults, e.g. reduced haematocrit, increased α-1 acid glycoprotein, decreased albumin and reduced glomerular filtration rate (GFR), which may influence imatinib pharmacokinetics. Given that Chinese cancer patients often report raised imatinib plasma concentrations and wider inter-individual variability reported in trough concentration when compared to Caucasian cancer patients, therapeutic drug monitoring (TDM) has been advocated.

METHOD

This study utilised a previously validated a Chinese cancer population and assessed the impact of imatinib virtual-TDM in Chinese and Caucasian cancer populations across a dosing range from 200-800 mg daily.

RESULTS

Staged dose titration to 800 mg daily, resulted in recapitulation to within the target therapeutic range for 50 % (Chinese) and 42.1% (Caucasian) subjects possessing plasma concentration < 550 ng/mL when dosed at 400 mg daily. For subjects with plasma concentrations >1500 ng/mL when dosed at 400 mg daily, a dose reduction to 200 mg once daily was able to recover 67 % (Chinese) and 87.4 % (Caucasian) patients to the target therapeutic range.

CONCLUSION

Virtual TDM highlights the benefit of pharmacokinetic modelling to optimising treatments in challenging oncology population groups.

Changes in imatinib plasma trough level during long-term treatment in patients with intermediate- or high-risk gastrointestinal stromal tumors: Relationship between covariates and imatinib plasma trough level

Background

Imatinib is the first-line adjuvant treatment for gastrointestinal stromal tumors (GISTs). Considering that some studies have suggested that imatinib (IM) plasma trough levels (C_min) change with time, the aim of this study is to assess the changes in IM C_min in patients with GIST in a long-term study and to elucidate the relationships between clinicopathological features and IM C_min.

Methods

In 204 patients with intermediate- or high-risk GIST who were taking IM, IM C_min was analyzed. Patient data were grouped according to the duration of medication (A: 1-3 months, B: 4-6 months, C: 7-9 months, D: 10-12 months, E: ≤12 months, F: 12<-≤36 months, G: >36 months). The correlation between IM C_min at different time stages and clinicopathological characteristics was assessed.

Results

Statistically significant differences were observed between Groups A, C, and D (P = 0.049 and 0.01, respectively). In Group E, IM C_min correlated with sex (P = 0.049) and age (P = 0.029) and negatively correlated with body weight, height, and body surface area (P = 0.007, 0.002, and 0.001, respectively). In Groups F and G, IM C_min was significantly higher in non-gastric operation patients than in patients with gastrectomy (P = 0.002, 0.036) and was significantly higher in patients with the primary sites of others than in the stomach (P < 0.001, = 0.012). In addition, IM C_min was much higher in patients with mutation sites other than KIT exon 11 in Group F (P = 0.011).

Conclusion

This is the first study of IM C_min during the long-term treatment of patients with intermediate- or high-risk GIST. IM C_min was the highest for the first 3 months and then declined, and long-term administration of IM showed a relatively stable plasma trough level. The IM C_min correlated with different clinical characteristics at different durations of medication. This meant that future "trough level-clinicopathological characteristics" analyses should be time-point-specific. We also need to formulate time-specific medication monitoring plans in clinical practice to study disease progression caused by the occurrence of drug resistance.

Relationship between achievement of major molecular response or deep molecular response and nilotinib plasma concentration in patients with chronic myeloid leukemia receiving first-line nilotinib therapy

PURPOSE

We evaluated the plasma exposure and response relationships of nilotinib for patients with newly diagnosed chronic myeloid leukemia (CML) in real-world practice.

METHODS

For the 26 patients enrolled in this study, at 3, 6, 12, and 24 months after nilotinib administration, the trough plasma concentrations (C_trough) of nilotinib were analyzed. The relationships between nilotinib C_trough and the molecular response to nilotinib treatment at each point (each n = 26) were evaluated.

RESULTS

Median nilotinib C_trough values were significantly higher in patients with a major molecular response (MMR) at 3 months than in patients without an MMR (809 and 420 ng/mL, respectively; P = 0.046). Based on the area under the receiver-operating characteristic curve, the threshold value of the nilotinib C_trough at 3 months for predicting MMR achievement was 619 ng/mL at the best sensitivity (71.4%) and specificity (77.8%). Patients with a nilotinib C_trough of above 619 ng/mL had a significantly shorter time to achievement of a deep molecular response (DMR; 9.0 and 18.0 months, respectively; P = 0.020) and higher rates of DMR by 2 years in Kaplan-Meier plots (P = 0.025) compared with that in patients with a nilotinib C_trough of less than 619 ng/mL.

CONCLUSION

For patients with newly diagnosed CML, the nilotinib dose may be adjusted using a C_trough of above 619 ng/mL as the minimum effective concentration, i.e., the lowest concentration required for MMR or DMR achievement within a shorter time, during early stages after beginning therapy to obtain faster and deeper clinical responses.

Individualized Management of Blood Concentration in Patients with Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor, and surgical resection is the first choice for the treatment of the disease, but since the advent of tyrosine kinase inhibitors (TKIs) such as imatinib (IM), the prognosis of the disease has undergone revolutionary changes. According to the current version of the guidelines, most GIST patients receive a fixed dose without taking into account their own individual differences, resulting in a wide difference in blood concentration, adverse reactions and prognosis. With more studies on the relationship between blood drug concentrations and prognosis, the concept of individualized therapy has been paid more attention by researchers. Therapeutic drug monitoring (TDM) has also been made available for the research field of GIST targeted therapy. How to reduce the incidence of drug resistance and adverse reactions in patients with GISTs has become the focus of the current research. This article reviews the common monitoring methods and timing of TKIs blood concentration, the reasonable range of blood drug concentration, the toxic or adverse effects caused by high blood drug concentration, some possible factors affecting blood drug concentration and recent research progress, in order to discuss and summarize the treatment strategy of individual blood drug concentration, improve the prognosis of patients and reduce the adverse effects as much as possible.

Factors Influencing the Steady-State Plasma Concentration of Imatinib Mesylate in Patients With Gastrointestinal Stromal Tumors and Chronic Myeloid Leukemia

Imatinib mesylate (IM) is the standard treatment for advanced, metastatic gastrointestinal stromal tumors (GISTs) and chronic myeloid leukemia (CML) with a fixed daily standard dosage via the oral route. Interindividual and intraindividual variability in plasma concentrations have been closely linked to the efficacy of IM therapy. Therefore, this review identifies and describes the key factors influencing the plasma concentration of IM in patients with GISTs and CML. We used the following keywords to search the PubMed, EMBASE, Ovid, Wangfang, and CNKI databases to identify published reports: IM, plasma concentration, GISTs, CML, drug combination/interaction, pathology, and genotype/genetic polymorphism, either alone or in combination. This literature review revealed that only 10 countries have reported the mean concentrations of IM in GISTs or CML patients and the clinical outcomes in different ethnic groups and populations. There were totally 24 different gene polymorphisms, which were examined for any potential influence on the steady-state plasma concentration of IM. As a result, some genotype locus made discrepant conclusion. Herein, the more sample capacity, multicenter, long-term study was worthy to carry out. Eleven reports were enumerated on clinical drug interactions with IM, while there is not sufficient information on the pharmacokinetic parameters altered by drug combinations with IM that could help in investigating the actual drug interactions. The drug interaction with IM should be paid more attention in the future research.

Therapeutic drug monitoring-based dose optimization for imatinib-associated serious cutaneous reactions in a patient with gastrointestinal stromal tumours: A case report

WHAT IS KNOWN AND OBJECTIVE

Imatinib mesylate (IM) is the first-line therapy for unresectable or metastatic gastrointestinal stromal tumours (GISTs). Here, we report a case of successful progressive dose optimization by therapeutic drug monitoring (TDM) for a patient with GISTs who developed IM-associated serious cutaneous reactions.

CASE DESCRIPTION

A 72-year-old female patient received IM at a dose of 400 mg/day for GISTs. The patient developed serious eczematoid drug eruptions and desquamation, following which IM was discontinued. One year later, the GISTs recurred with metastasis, and IM was re-administered at a dose of 100 mg/day, and the dose was gradually increased on the basis of TDM. The final dose of IM was 200 mg/day, and the trough concentration (C_trough ) of IM was 1457.76 ng/mL. The images obtained from follow-up computed tomography (CT) showed a marked anti-tumour response. IM was well tolerated and the patient developed tolerable IM-associated cutaneous reactions.

WHAT IS NEW AND CONCLUSION

The strategy of TDM-guided dose optimization makes it possible to achieve optimal clinical efficacy for patients with GISTs who develop IM-associated serious cutaneous reactions.

Correlations between imatinib plasma trough concentration and adverse reactions in Chinese patients with gastrointestinal stromal tumors

BACKGROUND

Imatinib is the standard treatment for patients with gastrointestinal stromal tumors (GISTs), but there is significant variation in imatinib plasma trough concentrations (C_min ) among patients. The imatinib C_min distribution at different doses and the correlation of adverse reactions with C_min in Chinese patients with GIST from a high-volume center were evaluated.

METHODS

From July 1, 2017 to December 31, 2018, patients who were receiving imatinib treatment for GIST were prospectively enrolled. Steady-state blood samples were obtained from patients who had received same-dose imatinib treatment for ≥1 month with good compliance. Adverse reactions were recorded during regular follow-up, and blood samples were collected 24 ± 2 hours after dosing. Liquid chromatography-tandem mass spectrometry was used to measure drug concentrations.

RESULTS

In total, 307 patients who received 367 dose levels were investigated. The imatinib C_min was 1315 ± 716 ng/mL, 2117 ± 597 ng/mL, and 3844 ± 987 ng/mL in patients who were receiving imatinib 400 mg, 600 mg, and 800 mg daily, respectively. The C_min was significantly correlated with periorbital and limb edema (P < .001), anemia (P < .001), and rash (P = .037). Nausea and vomiting, diarrhea, and conjunctival hemorrhage also were correlated, but not significantly. A much higher C_min was observed with severe adverse reactions. There was no correlation between the imatinib C_min and leukopenia, muscle cramps, or hepatobiliary dysfunction.

CONCLUSIONS

In Chinese patients with GIST, the imatinib C_min was higher than that reported for Western populations, especially at higher doses. The C_min was correlated with periorbital and limb edema, anemia, and rash, suggesting that monitoring the imatinib C_min should be considered when patients develop severe adverse reactions caused by excessive imatinib plasma concentrations.

Imatinib, sunitinib and pazopanib: From flat-fixed dosing towards a pharmacokinetically guided personalized dose

Tyrosine kinase inhibitors (TKIs) are anti‐cancer drugs that target tyrosine kinases, enzymes that are involved in multiple cellular processes. Currently, multiple oral TKIs have been introduced in the treatment of solid tumours, all administered in a fixed dose, although large interpatient pharmacokinetic (PK) variability is described. For imatinib, sunitinib and pazopanib exposure‐treatment outcome (efficacy and toxicity) relationships have been established and therapeutic windows have been defined, therefore dose optimization based on the measured blood concentration, called therapeutic drug monitoring (TDM), can be valuable in increasing efficacy and reducing the toxicity of these drugs.

In this review, an overview of the current knowledge on TDM guided individualized dosing of imatinib, sunitinib and pazopanib for the treatment of solid tumours is presented. We summarize preclinical and clinical data that have defined thresholds for efficacy and toxicity. Furthermore, PK models and factors that influence the PK of these drugs which partly explain the interpatient PK variability are summarized. Finally, pharmacological interventions that have been performed to optimize plasma concentrations are described. Based on current literature, we advise which methods should be used to optimize exposure to imatinib, sunitinib and pazopanib.