Imatinib induced severe skin reactions and neutropenia in a patient with gastrointestinal stromal tumor

Bullous Pemphigoid Occurring after Stopping Imatinib Therapy of CML: Is a Continuation of Post-Treatment Follow-Up Needed?

Advancements and the use of tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of Chronic Myeloid Leukemia (CML), achieving unprecedented success rates and expanding their applications to various neoplasms. However, the use of TKIs is not without its drawbacks. Skin, gastrointestinal, and central nervous systems are particularly susceptible to adverse effects, including a higher incidence of autoimmune responses in treated individuals. In this report, we present a unique case of bullous pemphigoid, a rare autoimmune disease, which has not been previously associated with TKI therapy as an adverse effect, particularly appearing after discontinuing Imatinib® treatment.

Discovery of an agonistic Siglec-6 antibody that inhibits and reduces human mast cells

Mast cells (MC) are key drivers of allergic and inflammatory diseases. Sialic acid-binding immunoglobulin-like lectin (Siglec)-6 is an immunoregulatory receptor found on MCs. While it is recognized that engaging Siglecs with antibodies mediates inhibition across immune cells, the mechanisms that govern this agonism are not understood. Here we generated Siglec-6 mAb clones (AK01 to AK18) to better understand Siglec-6-mediated agonism. Siglec-6 mAbs displayed epitope-dependent receptor internalization and inhibitory activity. We identified a Siglec-6 mAb (AK04) that required Fc-mediated interaction for receptor internalization and induced inhibition and antibody-dependent cellular phagocytosis against MCs. AK04-mediated MC inhibition required Siglec-6 immunoreceptor tyrosine-based inhibitory motif (ITIM) and ITIM-like domains and was associated with receptor cluster formation containing inhibitory phosphatases. Treatment of humanized mice with AK04 inhibited systemic anaphylaxis with a single dose and reduced MCs with chronic dosing. Our findings suggest Siglec-6 activity is epitope dependent and highlight an agonistic Siglec-6 mAb as a potential therapeutic approach in allergic disease.

Anti-apoptotic HAX-1 suppresses cell apoptosis by promoting c-Abl kinase-involved ROS clearance

The anti-apoptotic protein HAX-1 has been proposed to modulate mitochondrial membrane potential, calcium signaling and actin remodeling. HAX-1 mutation or deficiency results in severe congenital neutropenia (SCN), loss of lymphocytes and neurological impairments by largely unknown mechanisms. Here, we demonstrate that the activation of c-Abl kinase in response to oxidative or genotoxic stress is dependent on HAX-1 association. Cellular reactive oxygen species (ROS) accumulation is inhibited by HAX-1-dependent c-Abl activation, which greatly contributes to the antiapoptotic role of HAX-1 in stress. HAX-1 (Q190X), a loss-of-function mutant responsible for SCN, fails to bind with and activate c-Abl, leading to dysregulated cellular ROS levels, damaged mitochondrial membrane potential and eventually apoptosis. The extensive apoptosis of lymphocytes and neurons in Hax-1-deficient mice could also be remarkably suppressed by c-Abl activation. These findings underline the important roles of ROS clearance in HAX-1-mediated anti-apoptosis by c-Abl kinase activation, providing new insight into the pathology and treatment of HAX-1-related hereditary disease or tumorigenesis.

Development and external validation of a nomogram for individualized adjuvant imatinib duration for high-risk gastrointestinal stromal tumors: A multicenter retrospective cohort study

Introduction

The main emphasis of the research about adjuvant imatinib for high‐risk gastrointestinal stromal tumors (GISTs) is prolonging the treatment duration and ignores the heterogeneous that 10‐year recurrence rates ranged from about 20%–100%. Thus, this study evaluated the effect of different durations of adjuvant imatinib on outcomes in high‐risk GISTs to explore the feasibility of individual treatment.

Methods

We analyzed 855 high‐risk GIST patients from three centers who underwent macroscopically complete resection between December 2007 and September 2020. The patients were divided into training (n =564) and two validation cohorts (n = 238 and53) based on their source. Recurrence‐free survival (RFS) was the primary point. Cox multivariate analysis was used to develop the nomogram. C‐index, time‐dependent area under the curves, and calibration plots were used to assess the performance of the nomogram.

Results

Univariate analysis showed that longer adjuvant imatinib was significantly associated with better 5‐year RFS (p < 0.0001). Further investigation identified that the same high‐risk patients with lower tumor‐associated recurrence risk benefitted little from prolonged treatment and that the recommended adjuvant imatinib duration was insufficient for those with higher recurrence risk. A nomogram for predicting 2‐, 3‐, and 5‐year RFS based on different treatment durations and four major risk factors, namely, tumor site, size, mitotic count, and rupture status, was built and validated, with a C‐index of 0.82, 0.74, and 0.70 in training and two external validation cohorts, respectively. An online dynamic nomogram was further developed for clinical applications (https://ruolinliu666.shinyapps.io/GIST/), offering predictive recurrence rates based on different treatment durations and tumor features.

Conclusions

We developed a nomogram to predict the recurrence risk for high‐risk patients according to tumor features and treatment durations of imatinib to help physicians on decision‐making for individualized treatment duration.

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.

Slow desensitization of imatinib-induced nonimmediate reactions and dynamic changes of drug-specific CD4+CD25+CD134+ lymphocytes

BACKGROUND

Imatinib is a tyrosine kinase inhibitor indicated for the treatment of gastrointestinal stromal tumors (GISTs) and certain neoplastic diseases; however, nonimmediate adverse reactions are common.

OBJECTIVE

To describe the process of imatinib slow desensitization in patients who experienced nonimmediate reactions to imatinib and the dynamic change in drug-specific CD4⁺CD25⁺CD134⁺ T-lymphocyte percentages.

METHODS

Five patients diagnosed as having GISTs and with a recent history of imatinib-induced nonimmediate reactions (maculopapular exanthema with eosinophilia, exfoliative dermatitis, palmar-plantar erythrodysesthesia, and drug rash with eosinophilia and systemic symptoms) were desensitized using a slow desensitization protocol. The reintroduced imatinib dosage was stepped up every week starting from 10 mg/d and increasing to 25, 50, 75, 100, 150, 200, and 300 mg/d until the target dose of 400 mg/d was achieved. Prednisolone of up to 30 mg/d was allowed if allergic reactions recurred. The percentages of CD4⁺CD25⁺CD134⁺ T cells present after incubating peripheral blood mononuclear cells with imatinib, at baseline and after successful desensitization, were analyzed using flow cytometric analysis.

RESULTS

By using a slow desensitization technique, all patients were able to receive 400 mg/d of imatinib, and prednisolone was gradually tapered off. The percentages of imatinib-induced CD4⁺CD25⁺CD134⁺ T cells decreased from a mean (SD) of 11.3% (6.5%) and 13.4% (7.3%) at baseline to 3.2% (0.7%) and 3.0% (1.1%) after successful desensitization, when stimulating peripheral blood mononuclear cells with 1 and 2 μM of imatinib, respectively.

CONCLUSION

Slow desensitization is a helpful procedure in treating patients with imatinib-induced nonimmediate reactions other than simple maculopapular exanthema. The reduced percentages of imatinib-induced CD4⁺CD25⁺CD134⁺ T cells in these patients may be associated with immune tolerance.

A Case of Disseminated Intra-abdominal Gastrointestinal Stromal Tumor Managed with Low Dose Imatinib

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract. Imatinib mesylate is recommended as adjuvant therapy for GIST after surgical resection. However, drug-related adverse events are common. A 74-year-old female with metastatic GIST who was managed with imatinib experienced severe adverse events, including skin rashes, tremor, and alopecia, etc. The imatinib dose was reduced and the size of the metastatic GIST continued to decrease and adverse events showed significant improvement.

Imatinib-induced agranulocytosis in patients with gastrointestinal stromal tumors

Agranulocytosis is a rare but serious side effect of imatinib in gastrointestinal stromal tumor (GIST) patients. Imatinib is an inhibitor of the proto-oncogene tyrosine kinase (c-kit) and the first-line agent in patients with locally advanced and metastatic GIST. Little evidence is available on the management of this adverse event, and consensus-based guidelines are lacking. In this article, we describe 4 patients with agranulocytosis after starting imatinib. In addition, an overview of the available literature concerning the underlying mechanisms is given, and therapeutic strategies for overcoming this adverse event are discussed. In our experience it appears safe to restart imatinib after normalization of neutrophil count. In case of relapse of agranulocytosis, reintroduction combined with prednisolone, with treatment with granulocyte colony-stimulating factor or dose reduction can be considered.

Use of total and unbound imatinib and metabolite LC-MS/MS assay to understand individual responses in CML and GIST patients

OBJECTIVES

Trough total imatinib (t-IM) concentrations have been reported to be associated with therapeutic and toxic responses in patients with chronic myelogenous leukemia (CML) and gastrointestinal stromal tumor (GIST). Little is known about the relationships between effects and concentrations of either unbound imatinib (f-IM) or imatinib's major metabolite, N-desmethyl imatinib (NDI). In part, this is because of the lack of a single, validated, well-described clinically useful assay for these measurements. The authors report the development and application of such an assay.

MATERIALS AND METHODS

A single liquid-chromatography tandem-mass-spectrometry assay was used to monitor t-IM, f-IM, and t-NDI concentrations in CML and GIST patients treated at a tertiary German teaching hospital. The assay was also validated for measuring other kinase inhibitors, including t-nilotinib, sunitinib, and erlotinib. Ultrafiltration assays were validated and used to measure f-IM and to compare free fractions to plasma α1-acid glycoprotein concentrations (AGP).

RESULTS

The assays were linear over a working range (in micrograms per liter) of 8.4-8370, 8.3-4165, and 1.0-250 and had within- and between-run coefficient of variance of <7%, <12%, and <9% for t-IM, t-NDI, and f-IM, respectively. The f-IM assay was reproducible despite high (25.2%-31.6%) but concentration-independent binding to ultrafiltration devices. Clinically relevant results, such as nondetectable (ND) t-IM (<8.4 μg/L) in non-responders and >1500 μg/L in patients with major toxicity, were found. Of 156 total samples from 68 adult CML patients and 127 total samples from 42 adult GIST, only 48 samples from 22 CML patients and 40 samples from 20 GIST patients were trough samples with adequate dosing and collection information. More than half (27 of 48 CML and 24 of 40 GIST) had t-IM concentrations ≥10% below recommended target concentrations (1002 μg/L for CML and 1100 μg/L for GIST). Concentrations >50% over targets were also found in 6 of 48 CML and 4 of 40 GIST samples. Wide variations in concentrations of t-IM (range, ND to 2973 μg/L), t-NDI (range, ND to 659 μg/L), f-IM (range, 8.3-262 μg/L), and t-IM:f-IM ratios (range, 2.6%-14%) were found both between and within patients. A statistically significant association (Spearman correlation coefficient and P value for all samples, r = 0.290 and P = 0.023; for trough only, r = -0.585 and P = 0.028) was found between AGP and f-IM concentrations but wide interpatient and intrapatient variations made individual predictions unreliable.

CONCLUSIONS

The liquid-chromatography tandem-mass-spectrometry methods developed provided information useful to understand individual responses to therapy even though necessary sampling and dosing information was often not available. Wide unpredictable variations in t-IM, t-NDI, and f-IM were found. Clinical outcome trials are needed to examine whether f-IM or NDI monitoring can improve the ability to predict individual responses.