Pharmacokinetic and cytokine profiles of melanoma patients with dabrafenib and trametinib-induced pyrexia

Five-year analysis of neoadjuvant dabrafenib and trametinib for stage III melanoma

BACKGROUND

Neoadjuvant dabrafenib plus trametinib has a high pathological response rate and impressive short-term survival in patients with resectable stage III melanoma. We report 5-year outcomes from the phase II NeoCombi trial.

PATIENTS AND METHODS

NeoCombi (NCT01972347) was a single-arm, open-label, single-centre, phase II trial. Eligible patients were adults (aged ≥18 years) with histologically confirmed, resectable, RECIST-measurable, American Joint Committee on Cancer seventh edition clinical stage IIIB-C BRAF V600E/K-mutant melanoma and Eastern Cooperative Oncology Group performance status ≤1. Patients received 52 weeks of treatment with dabrafenib 150 mg (orally twice per day) plus trametinib 2 mg (orally once per day), with complete resection of the pre-therapy tumour bed at week 12.

RESULTS

Between 20 August 2014 and 19 April 2017, 35 patients were enrolled. At data cut-off (17 August 2021), the median follow-up was 60 months [95% confidence interval (CI) 56-72 months]. Overall, 21 of 35 (60%) patients recurred, including 12 (57%) with first recurrence in locoregional sites (followed by later distant recurrence in 6) and 9 (43%) with first recurrence in distant sites, including 3 in the brain. Most recurrences occurred within 2 years, with no recurrences beyond 3 years. At 5 years, recurrence-free survival (RFS) was 40% (95% CI 27% to 60%), distant metastasis-free survival (DMFS) was 57% (95% CI 42% to 76%), and overall survival was 80% (95% CI 67% to 94%). Five-year survival outcomes were stratified by pathological response: RFS was 53% with pathological complete response (pCR) versus 28% with non-pCR (P = 0.087), DMFS was 59% versus 55% (P = 0.647), and overall survival was 88% versus 71% (P = 0.205), respectively.

CONCLUSIONS

Neoadjuvant dabrafenib plus trametinib has high pathological response rates in clinical stage III melanoma, but low rates of RFS, similar to those achieved with adjuvant targeted therapy alone. Patients with a pCR to dabrafenib plus trametinib still had a high risk of recurrence, unlike that seen with immunotherapy where recurrences are rare.

Toxicities from BRAF and MEK Inhibitors: Strategies to Maximize Therapeutic Success

PURPOSE OF REVIEW

This report highlights several of the recent therapeutic advancements in the treatment of BRAF-mutant tumors, discusses the most common adverse events observed with BRAF-targeted agents, and suggests strategies to manage and mitigate treatment-related toxicities.

RECENT FINDINGS

BRAF and MEK inhibitors represent a significant advancement in the treatment of BRAF-mutated malignancies with data across tumor types demonstrating the anti-tumor efficacy of dual MAPK inhibition. Although these agents have a reasonable toxicity profile, variable side effects across organ systems can develop. The discovery of activating BRAF mutations and subsequent development of BRAF and MEK inhibitors has transformed the treatment algorithms of BRAF-mutant malignancies. With increased application of these targeted regimens, identification and prompt management of their unique adverse events are crucial.

MEK inhibition induces expression of differentiation marker Keratin 10 in human keratinocytes

BRAF mutant metastatic melanoma was regularly treated in the past with a BRAF inhibitor (BRAFi) alone or in combination with inhibitors of the mitogen-activated protein kinase kinase (MEKi), which is still a common treatment. This combination therapy strongly reduced the occurrence of keratoacanthomas and squamous cell carcinoma, which was frequently seen when BRAFi was used as monotherapy. Here we addressed the question whether MEK inhibition counteracts squamous cell carcinoma development in part by promoting keratinocyte differentiation. Exposure of human immortalized keratinocytes to different concentrations of MEKi revealed a significant increase in the expression of differentiation-associated keratins K10 and K1 as determined by qRT-PCR and immunofluorescence staining. Taken together, the present study suggests that in a combined treatment of melanoma with BRAFi/MEKi, MEKi reduces the incidence of squamous cell carcinomas by promoting keratinocyte differentiation under combined BRAFi/MEKi treatment in melanoma. This might open further treatment perspectives for skin cancer treatment.

Development and validation of an LC-MS/MS method to measure the BRAF inhibitors dabrafenib and encorafenib quantitatively and four major metabolites semi-quantitatively in human plasma

This article describes the development and validation of a liquid-chromatography coupled with tandem mass spectrometry (LC-MS/MS) assay for the simultaneous quantitation of the BRAF inhibitors dabrafenib and encorafenib, and semi-quantitation of their major metabolites (i.e., carboxy-dabrafenib, desmethyl-dabrafenib, hydroxy-dabrafenib, M42.5A) in human plasma. Analytes were extracted from human plasma by protein precipitation, followed by reversed phase high-performance liquid chromatography. Analyte detection was performed using tandem mass spectrometry with heated electrospray ionization operating in positive ion mode. The assay was validated in accordance with the current U.S. Food and Drug Administration Guidance on Bioanalytical Method Validation. Results showed that measurements were both accurate (94.6-112.0 %) and precise (within-run: 1.9-3.4 %; between-run: 1.7-12.0 %) spanning a concentration range of 5 to 2000 ng/mL for dabrafenib and 10 to 4000 ng/mL for encorafenib. Recoveries for these analytes were consistent with mean values ranging from 85.6 % to 90.9 %. The mean internal standard-normalized matrix factors for each drug ranged between 0.87 and 0.98 and were found to be precise (% RSD <6.4 %). Dabrafenib and encorafenib were stable in the final extract and in human plasma held under various storage conditions. The metabolites also passed the validation criteria for precision and selectivity. Finally, the clinical applicability of the assay was confirmed by (semi-)quantitation of all six analytes in plasma samples from cancer patients receiving standard-of-care treatment with dabrafenib and encorafenib. Reproducibility of the measured analyte concentrations in study samples was confirmed successfully by incurred sample reanalysis. In conclusion, this sensitive LC-MS/MS assay has been validated successfully and is suitable for therapeutic drug monitoring of dabrafenib and encorafenib and clinical pharmacokinetic studies with these BRAF inhibitors.

Exposure-response analyses of BRAF- and MEK-inhibitors dabrafenib plus trametinib in melanoma patients

INTRODUCTION

Dabrafenib and trametinib are currently administered at fixed doses, at which interpatient variability in exposure is high. The aim of this study was to investigate whether drug exposure is related to efficacy and toxicity in a real-life cohort of melanoma patients treated with dabrafenib plus trametinib.

PATIENTS AND METHODS

An observational study was performed in which pharmacokinetic samples were collected as routine care. Using estimated dabrafenib Area Under the concentration-time Curve and trametinib trough concentrations (C_min), univariable and multivariable exposure-response analyses were performed.

RESULTS

In total, 140 patients were included. Dabrafenib exposure was not related to either progression-free survival (PFS) or overall survival (OS). Trametinib exposure was related to survival, with C_min ≥ 15.6 ng/mL being identified as the optimal threshold. Median OS was significantly longer in patients with trametinib C_min ≥ 15.6 ng/mL (22.8 vs. 12.6 months, P = 0.003), with a multivariable hazard ratio of 0.55 (95% CI 0.36-0.85, P = 0.007). Median PFS in patients with trametinib C_min levels ≥ 15.6 ng/mL (37%) was 10.9 months, compared with 6.0 months for those with C_min below this threshold (P = 0.06). Multivariable analysis resulted in a hazard ratio of 0.70 (95% CI 0.47-1.05, P = 0.082). Exposure to dabrafenib and trametinib was not related to clinically relevant toxicities.

CONCLUSIONS

Overall survival of metastasized melanoma patients with trametinib C_min levels ≥ 15.6 ng/mL is ten months longer compared to patients with C_min below this threshold. This would theoretically provide a rationale for therapeutic drug monitoring of trametinib. Although a high proportion of patients are underexposed, there is very little scope for dose increments due to the risk of serious toxicity.

Challenges in the treatment of melanoma with BRAF and MEK inhibitors in patients with sickle cell disease: case report and review of the literature

Patients with sickle cell disease (SCD) suffer from complications due to anemia, inflammation, and vaso-occlusion. Factors that trigger sickling and/or inflammation may initiate such complications, while treatment with hydroxyurea (HU) reduces their emergence and prolongs survival. On the contrary, inhibition of the BRAF-MEK-ERK pathway with BRAF and MEK inhibitors (BRAF/MEKi) has revolutionized treatment of melanoma but their use has been correlated with inflammatory adverse events. Thus, treatment of patients with SCD with BRAF/MEKi may be quite challenging and pyrexia in those patients should be managed as a medical emergency. In this article, intrigued by the case of a 36-year-old female patient with S/β-thal under HU who was treated with dabrafenib and trametinib for melanoma, we analyze the mechanisms underlying inflammation and vaso-occlusion in SCD, the mechanisms of pyrexia and inflammation induced by BRAF/MEKi, their potential interconnections, the shared role of the inflammasome in these two entities, and the protective effect of HU in SCD. Since SCD is the most common inheritable blood disorder, the administration of BRAF/MEKi for melanoma in patients with SCD may be a rather common challenge. Thus, proper treatment with HU may pave the way for an uneventful management of such patients.

Cellular and Molecular Mechanisms of MEK1 Inhibitor-Induced Cardiotoxicity

Background

Trametinib is a MEK1 (mitogen-activated extracellular signal-related kinase kinase 1) inhibitor used in the treatment of BRAF (rapid accelerated fibrosarcoma B-type)-mutated metastatic melanoma. Roughly 11% of patients develop cardiomyopathy following long-term trametinib exposure. Although described clinically, the molecular landscape of trametinib cardiotoxicity has not been characterized.

Objectives

The aim of this study was to test the hypothesis that trametinib promotes widespread transcriptomic and cellular changes consistent with oxidative stress and impairs cardiac function.

Methods

Mice were treated with trametinib (1 mg/kg/d). Echocardiography was performed pre- and post-treatment. Gross, histopathologic, and biochemical assessments were performed to probe for molecular and cellular changes. Human cardiac organoids were used as an in vitro measurement of cardiotoxicity and recovery.

Results

Long-term administration of trametinib was associated with significant reductions in survival and left ventricular ejection fraction. Histologic analyses of the heart revealed myocardial vacuolization and calcification in 28% of animals. Bulk RNA sequencing identified 435 differentially expressed genes and 116 differential signaling pathways following trametinib treatment. Upstream gene analysis predicted interleukin-6 as a regulator of 17 relevant differentially expressed genes, suggestive of PI3K/AKT and JAK/STAT activation, which was subsequently validated. Trametinib hearts displayed elevated markers of oxidative stress, myofibrillar degeneration, an 11-fold down-regulation of the apelin receptor, and connexin-43 mislocalization. To confirm the direct cardiotoxic effects of trametinib, human cardiac organoids were treated for 6 days, followed by a 6-day media-only recovery. Trametinib-treated organoids exhibited reductions in diameter and contractility, followed by partial recovery with removal of treatment.

Conclusions

These data describe pathologic changes observed in trametinib cardiotoxicity, supporting the exploration of drug holidays and alternative pharmacologic strategies for disease prevention.

Monitoring of Dabrafenib and Trametinib in Serum and Self-Sampled Capillary Blood in Patients with BRAFV600-Mutant Melanoma

Patients treated with dabrafenib and trametinib for BRAFV600-mutant melanoma often experience dose reductions and treatment discontinuations. Current knowledge about the associations between patient characteristics, adverse events (AE), and exposure is inconclusive. Our study included 27 patients (including 18 patients for micro-sampling). Dabrafenib and trametinib exposure was prospectively analyzed, and the relevant patient characteristics and AE were reported. Their association with the observed concentrations and Bayesian estimates of the pharmacokinetic (PK) parameters of (hydroxy-)dabrafenib and trametinib were investigated. Further, the feasibility of at-home sampling of capillary blood was assessed. A population pharmacokinetic (popPK) model-informed conversion model was developed to derive serum PK parameters from self-sampled capillary blood. Results showed that (hydroxy-)dabrafenib or trametinib exposure was not associated with age, sex, body mass index, or toxicity. Co-medication with P-glycoprotein inducers was associated with significantly lower trough concentrations of trametinib (p = 0.027) but not (hydroxy-)dabrafenib. Self-sampling of capillary blood was feasible for use in routine care. Our conversion model was adequate for estimating serum PK parameters from micro-samples. Findings do not support a general recommendation for monitoring dabrafenib and trametinib but suggest that monitoring can facilitate making decisions about dosage adjustments. To this end, micro-sampling and the newly developed conversion model may be useful for estimating precise PK parameters.

A distinct four-value blood signature of pyrexia under combination therapy of malignant melanoma with dabrafenib and trametinib evidenced by an algorithm-defined pyrexia score

Pyrexia is a frequent adverse event of BRAF/MEK-inhibitor combination therapy in patients with metastasized malignant melanoma (MM). The study’s objective was to identify laboratory changes which might correlate with the appearance of pyrexia. Initially, data of 38 MM patients treated with dabrafenib plus trametinib, of which 14 patients developed pyrexia, were analysed retrospectively. Graphical visualization of time series of laboratory values suggested that a rise in C-reactive-protein, in parallel with a fall of leukocytes and thrombocytes, were indicative of pyrexia. Additionally, statistical analysis showed a significant correlation between lactate dehydrogenase (LDH) and pyrexia. An algorithm based on these observations was designed using a deductive and heuristic approach in order to calculate a pyrexia score (PS) for each laboratory assessment in treated patients. A second independent data set of 28 MM patients, 8 with pyrexia, was used for the validation of the algorithm. PS based on the four parameters CRP, LDH, leukocyte and thrombocyte numbers, were statistically significantly higher in pyrexia patients, differentiated between groups (F = 20.8; p = <0.0001) and showed a significant predictive value for the diagnosis of pyrexia (F = 6.24; p = 0.013). We provide first evidence that pyrexia in patients treated with BRAF/MEK-blockade can be identified by an algorithm that calculates a score.

Immune-mediated necrotizing myopathy with anti-signal recognition particle antibodies, in a patient with melanoma treated with BRAF/MEK inhibitors

The effect of serine/threonine-protein kinase B-Raf/mitogen-activated protein kinase (BRAF/MEK) inhibitors on the immune system is not clearly described, but rare cases of autoimmune phenomena have been reported. The clinical case we present below is the first report of a necrotizing myopathy related to dabrafenib/trametinib treatment. A 48-year-old man started dabrafenib/trametinib for stage IV BRAF-V600E mutated cutaneous melanoma. After the first month, he presented with grade 3 pyrexia (Common Terminology Criteria for Adverse Events [CTCAE] v.5.0.) and increased creatinine-kinase levels. A diagnosis of immune-mediated necrotizing myopathy, antisignal recognition particle (anit-SRP) positive, was made. At disease progression, dabrafenib/trametinib was restarted, triggering a new episode of grade 2 pyrexia and myositis. Treatment was changed to encorafenib/binimetinib without repeating pyrexia or limiting creatinine-kinase elevation, presenting even a loss of anti-SRP antibodies. Given the temporal relationship, the fact that re-exposition induced a new worsening of the myopathy and the loss of the anti-SRP antibodies after changing treatment, we infer that there possibly is a clear relationship between dabrafenib/trametinib treatment and the myopathy.

Interleukin-6 blockade for prophylaxis and management of immune-related adverse events in cancer immunotherapy

BACKGROUND

Immune checkpoint inhibitors (ICIs) have activity across many tumor types, but activation of the immune system may also lead to significant, often steroid-refractory immune-related adverse events (irAEs). We sought to determine the activity of tocilizumab, an anti-interleukin-6 receptor monoclonal antibody, in treatment or prevention of auto-immune irAE in ICI-treated patients.

METHODS

Institutional databases from 2 melanoma centers were reviewed for patients treated with ICIs and tocilizumab. Longitudinal assessment of C-reactive protein (CRP) and assessment of clinical improvement or prevention of flare of pre-existing auto-immune conditions were utilised to evaluate the benefit of tocilizumab.

RESULTS

Twenty-two patients were identified. Two were treated prophylactically. Twenty were treated for management of irAEs. Median time to irAE onset from ICI start was 48 days (range 8-786) and from irAE onset to tocilizumab 32 days (range 1-192). Median time to irAE resolution from tocilizumab was 6.5 days (range 1-93). Clinical improvement/benefit was demonstrated in 21/22 patients. Median CRP prior to ICI administration was 32 mg/l (range 0.3-99), at the onset of irAE 49.5 mg/L (range 0.3-251, P = 0.047) and after tocilizumab 18 mg/L (range 0.3-18, P = 0.0011). Tocilizumab was well tolerated with self-limiting and transient toxicities in 11 (50%) patients. From start of ICI, median progression-free survival was 6 months (range 3.9-18.8) and median overall survival was not reached.

CONCLUSIONS

Tocilizumab was a well-tolerated and effective steroid-sparing treatment for both management of irAEs, as well as prevention of flare of pre-existing auto-immune disorders. Prospective trials to evaluate its efficacy and impact on cancer outcomes compared with standard strategies are required.

Pyrexia in patients treated with dabrafenib plus trametinib across clinical trials in BRAF-mutant cancers

BACKGROUND

Dabrafenib plus trametinib has demonstrated clinical benefit across multiple BRAF-mutant tumours, leading to approval for resected stage III and metastatic melanoma, non-small-cell lung cancer (NSCLC) and anaplastic thyroid cancer. Pyrexia is a common adverse event in patients treated with dabrafenib plus trametinib. Here, we characterise the incidence, patterns and management of pyrexia in patients receiving dabrafenib plus trametinib in clinical trials.

METHODS

Patients (N = 1076) included in the analysis received dabrafenib plus trametinib in the following clinical trials: phase II registration trial in advanced NSCLC (N = 82), phase III COMBI-AD study in resectable stage III melanoma (N = 435) and phase III COMBI-d and COMBI-v studies in unresectable or metastatic melanoma (N = 209 and N = 350, respectively).

RESULTS

Among the 1076 patients enrolled in the clinical trials, 61.3% developed pyrexia, 5.7% developed grade 3/4 pyrexia and 15.6% developed a protocol-defined serious pyrexia event. Among the 660 patients with pyrexia, 33.0% had 1 occurrence, 19.8% had 2 occurrences and 47.1% had ≥3 occurrences. The incidence of pyrexia was highest early in treatment and decreased with time on treatment. Temporary dose interruption of dabrafenib or trametinib was the most common and effective management strategy.

CONCLUSIONS

Pyrexia is the most common adverse event associated with dabrafenib plus trametinib but is manageable with dose interruption.

TRIAL REGISTRATION

ClinicalTrials.gov (Phase II NSCLC, NCT01336634; COMBI-AD, NCT01682083; COMBI-d, NCT01584648; COMBI-v, NCT01597908).

Dabrafenib and trametinib exposure-efficacy and tolerance in metastatic melanoma patients: a pharmacokinetic-pharmacodynamic real-life study

PURPOSE

Dabrafenib plus trametinib combination has greatly improved survival in BRAFV600^mut metastatic melanoma patients. However, data regarding the influence of pharmacokinetic markers in real-life patients are lacking. In this study, we aimed to explore dabrafenib and trametinib pharmacokinetic impact on progression-free survival (PFS), duration of response (DOR) or all grades treatment-related adverse events (ARAE) occurrence in routine care patients.

METHODS

BRAFV600^mut metastatic melanoma patients initiating standard doses of dabrafenib 150 mg BID plus trametinib 2 mg QD were included. Clinical data were collected via the French biobank MelBase, prospectively enrolling unresectable stage III or IV melanoma. Clinical response evaluation, ARAE reporting and dabrafenib and trametinib plasma quantification were performed. Association of individual Bayesian-estimated pharmacokinetic markers (AUC_0-τ and C_trough) and baseline clinical variables with DOR, PFS, clinical response, and ARAE was then assessed.

RESULTS

Fifty patients (comprising 4 AJCC stage IIIc and 46 stage IV) were included. Median PFS reached 11.4 months, and overall response rate 70%. Fifty percent of patients experienced ARAE (G3 n = 10, G4 n = 0). In univariate analysis, median dabrafenib C_trough within intermediate range was associated with a significantly higher PFS (HR [95% CI] = 0.41 [0.18; 0.91], p = 0.029) and DOR (HR [95% CI] = 0.39 [0.16; 0.94], p = 0.024), and association with DOR remained significant in multivariate analysis (HR [95% CI] = 0.34 [0.12; 0.95], p = 0.040). Trametinib pharmacokinetic markers were significantly higher in patients experiencing ARAE compared to patients without ARAE.

CONCLUSION

In this study, exposure-efficacy and tolerance analysis highlighted the interest of therapeutic drug monitoring to optimize therapeutic management in BRAFV600^mut metastatic melanoma patients based on trough concentrations of dabrafenib and trametinib.

Simultaneous quantification of dabrafenib, hydroxy-dabrafenib and trametinib in human plasma by liquid chromatography-tandem mass spectrometry

A new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantification of dabrafenib (DAB), its main metabolite hydroxy-dabrafenib (OHD) and trametinib (TRA) in human plasma has been developed and validated. After addition of internal standard (dabrafenib-d9), extraction was achieved after protein precipitation with acetonitrile containing 1 % (v/v) formic acid. Chromatographic separation was performed on an Accucore® C18 (2.1 × 50 mm; 2.6 μm) column using a gradient elution of water acidified with 0.1 % (v/v) formic acid (A) and acetonitrile containing 0.1 % (v/v) formic acid (B) at a flow rate of 500 μL/min. The calibration ranged from 10 to 2000 ng/mL for DAB and OHD and from 5 to 50 ng/mL for TRA. This method was validated with satisfactory results including good precision (intra- and inter-assay coefficient of variation from 2.0 %-14.9 %) and good accuracy (inter- and intra-day bias between -1.2 % and 10.9 %), as well as long term stability in unprocessed plasma at -20 °C. This newly proposed method is useful for clinical research purposes as well as therapeutic drug monitoring for patients with a Rapidly Accelerated Fibrosarcoma kinase B (BRAF)-mutated cancer.

Population Pharmacokinetics/Pharmacodynamics of Dabrafenib Plus Trametinib in Patients with BRAF-Mutated Metastatic Melanoma

Patients treated with dabrafenib/trametinib (DAB/TRA) exhibit a large interindividual variability in clinical outcomes. The aims of this study were to characterize the pharmacokinetics of DAB, hydroxy-dabrafenib (OHD), and TRA in BRAF-mutated patients and to investigate the exposure–response relationship for toxicity and efficacy in metastatic melanoma (MM) patients. Univariate Fisher and Wilcoxon models including drug systemic exposure (area under the plasma concentration curve, AUC) were used to identify prognostic factors for the onset of dose-limiting toxicities (DLT), and Cox models for overall (OS) and progression-free survival (PFS). Seventy-three BRAF-mutated patients were included in pharmacokinetic (n = 424, NONMEM) and 52 in pharmacokinetic/pharmacodynamic analyses. Age and sex were identified as determinants of DAB and OHD clearances (p < 0.01). MM patients experiencing DLT were overexposed to DAB compared to patients without DLT (AUC: 9624 vs. 7485 ng∙h/mL, respectively, p < 0.01). Eastern Cooperative Oncology Group Performance Status (ECOG PS) ≥ 2 and plasma ratio AUC_OHD/AUC_DAB ≥ 1 were independently associated with shorter OS (HR: 6.58 (1.29–33.56); p = 0.023 and 10.61 (2.34–48.15), p = 0.022, respectively). A number of metastatic sites ≥3 and cerebral metastases were associated with shorter PFS (HR = 3.25 (1.11–9.50); p = 0.032 and HR = 1.23 (1.35–10.39), p = 0.011; respectively). TRA plasma exposure was neither associated with toxicity nor efficacy. Our results suggest that early drug monitoring could be helpful to prevent the onset of DLT in MM patients, especially in fragile patients such as the elderly. Regarding efficacy, the clinical benefit to monitor plasma ratio AUC_OHD/AUC_DAB deserves more investigation in a larger cohort of MM patients.

Dynamics of neutrophil and C-reactive protein reflect the clinical course of pyrexia during combination therapy with dabrafenib and trametinib

Pyrexia is the most common adverse event in patients with melanoma or other solid organ malignancies that are treated with the combination of dabrafenib and trametinib (combi-DT). Given the expanded indication for combi-DT, management of pyrexia is a high priority. No previous case series has revealed which blood markers reflect the course of pyrexia and there is no consensus on the management strategy for pyrexia. The current case series study describes the utility of neutrophil count (NC), neutrophil ratio (NR) and C-reactive protein (CRP) in 11 patients with metastatic melanoma and BRAF V600 mutations who experienced pyrexia during combi-DT in our department. We also described the clinical course of pyrexia episodes that were managed with the concomitant use of oral prednisolone and immediate withdrawal of combi-DT. Consequently, the analysis of 37 pyrexia episodes in 11 patients showed that the differences in NC, NR and CRP at the onset of pyrexia were significantly different from those at pyretolysis (P = 0.01, 0.006 and 0.03, respectively). Additionally, in the 24 pyrexia episodes treated with the concomitant use of oral prednisolone and the immediate withdrawal of combi-DT, the mean duration of pyrexia and the mean time to restart combi-DT were 3 and 6 days, respectively. Therefore, the blood markers that reflect the course of pyrexia during combi-DT may be helpful for the appropriate management of pyrexia; also, our management strategy for pyrexia successfully reduced the duration of pyrexia and did not require a long-term drug holiday. Further large-scale studies are required to verify our results.