Pharmacokinetics of Asciminib in Individuals With Hepatic or Renal Impairment

Population pharmacokinetic modeling of asciminib in support of exposure-response and ethnic sensitivity analyses in patients with chronic myeloid leukemia

BACKGROUND

The original population pharmacokinetics (popPK) model for asciminib in patients with chronic myeloid leukemia in chronic phase (CML-CP) was refined to address drug development needs in support of drug submission, namely, attainment of target drug exposure in specific patient populations, populating individual daily exposures for exposure-response analyses of key efficacy and safety endpoints, confirmation of comparability in exposure between 40 mg b.i.d. and 80 mg q.d., and assessment of ethnic insensitivity.

METHODS

Participants from two organ dysfunction studies, patients with CML in blast and acute phases and acute lymphoblastic leukemia and patients from a phase III efficacy study in newly diagnosed Ph + CML-CP, and data from a dedicated phase II study in the Chinese patients previously treated with at least two prior tyrosine kinase inhibitors, and a phase IIIb study comparing two dose regimens of asciminib (40 mg b.i.d. and 80 mg q.d.) were included in the revised popPK model. Covariates evaluated were line of therapy, baseline renal and hepatic functions, Chinese or Japanese ethnicity.

RESULTS

The apparent clearance and steady-state volume of distribution of asciminib were 6.84 L/h and 110 L, respectively, for a typical individual of 70 kg weight and 90 mL/min absolute glomerular filtration rate. Both the 40 mg b.i.d. and 80 mg q.d. resulted in a steady-state daily AUC of 12,600 ng.h/mL, and there was no difference between lines of therapy. Effects of renal or hepatic impairment on clearance were not clinically relevant. Chinese and Japanese exhibited similar PK as that of the global population.

CONCLUSIONS

The 40 mg b.i.d. and 80 mg q.d. regimens are comparable in their daily exposure, supporting the use of the two dosing regimens in newly diagnosed and previously treated CML-CP patients. The PK of asciminib is insensitive to ethnic differences and no dose adjustment is required for severe renal and hepatic impaired patients.

Safety and efficacy of asciminib in a patient with chronic myeloid leukemia on hemodialysis

The advent of tyrosine kinase inhibitors (TKIs) has revolutionized the treatment of chronic myeloid leukemia (CML), significantly improving patient prognosis. Asciminib, a novel specifically targeting the ABL myristoyl pocket inhibitor, has shown promise for CML patients unresponsive or intolerant to traditional TKIs. However, its use in hemodialysis patients remains underexplored. We present a case of a 71-year-old man with CML undergoing hemodialysis, successfully treated with asciminib. Initial treatment with bosutinib was effective but later failed, prompting a switch to asciminib. The patient achieved a major molecular response within 2 months without adverse effects. Pharmacokinetic analysis revealed significant drug clearance during hemodialysis, necessitating dosage adjustments. This case highlights the potential of asciminib in managing CML in hemodialysis patients, emphasizing the need for individualized treatment plans and close monitoring. Further studies are warranted to establish comprehensive guidelines for asciminib use in this unique patient population.

Caught in the Crossfire: Unmasking the Silent Renal Threats of Tyrosine Kinase Inhibitors in Chronic Myeloid Leukemia

BACKGROUND

Renal adverse drug reactions (ADRs) associated with tyrosine kinase inhibitors (TKIs) in the treatment of chronic myeloid leukemia (CML) are relatively rare, and there is currently no standardized protocol for their management. Therefore, this study aimed to summarize renal ADRs related to TKIs use in CML and propose an evidence-based approach to monitor and manage these ADRs.

METHODS

A systematic literature review was performed to identify renal ADRs associated with TKIs in CML. Two authors screened the search results and extracted data from 37 eligible studies. These findings were then used to develop a scheme for clinicians to monitor and manage these ADRs.

RESULTS

Overall, imatinib seemed to be significantly linked to renal adverse events compared to other TKIs, and switching to dasatinib or nilotinib significantly improved renal function. Similar events were reported with bosutinib, although they were not statistically significant. However, most of the renal events reported on dasatinib were described as nephrotic syndrome that resolved with switching to imatinib. Few cases were reported with nilotinib that described tumor lysis syndrome (TLS)-related kidney injury.

CONCLUSIONS

Recommendations include monitoring for progressive decline in the estimated glomerular filtration rate with imatinib, nephrotic syndrome with dasatinib, and TLS with nilotinib. Additionally, holding the offending TKI and managing renal ADRs according to local guidelines were adopted more frequently than reducing the TKI dose.

Clinical Pharmacology of Asciminib: A Review

Asciminib is a first-in-class allosteric inhibitor of the kinase activity of BCR::ABL1, specifically targeting the ABL myristoyl pocket (STAMP). This review focuses on the pharmacokinetic (PK) and pharmacodynamic data of asciminib, which is approved at a total daily dose of 80 mg for the treatment of adult patients with chronic myeloid leukemia in chronic phase who are either resistant or intolerant to ≥ 2 tyrosine kinase inhibitors or those harboring the T315I mutation (at a dose of 200 mg twice daily). Asciminib is predicted to be almost completely absorbed from the gut, with an absolute bioavailability (F) of approximately 73%. It should be administered in a fasted state, as food (particularly high-fat meals) reduces exposure. Asciminib displays a slightly greater than dose-proportional increase in exposure, with no time-dependent changes in PK observed following repeated dosing. This drug shows low clearance (6.31 L/h), with a moderate volume of distribution (111 L) and high human plasma protein binding (97.3%). The apparent terminal elimination half-life (t1/2) across studies was estimated to be between 7 and 15 h. The PK of asciminib is not substantially affected by body weight, age, gender, race, or renal or hepatic impairment. Asciminib is primarily metabolized via CYP3A4-mediated oxidation (36.0%) and UGT2B7- and UGT2B17-mediated glucuronidation (13.3% and 7.8%, respectively); biliary secretion via breast cancer resistance protein contributes to about 31.1% to total systemic clearance, which is mainly through hepatic metabolism and biliary secretion through the fecal pathway, with renal excretion playing a minor role. The potential for PK drug interaction for asciminib both as a victim and a perpetrator has been summarized here based on clinical and predicted drug-drug interaction studies. Robust exposure-response models characterized asciminib exposure-efficacy and exposure-safety relationships. In patients without the T315I mutation, the exposure-efficacy analysis of the time course of BCR::ABL1IS percentages highlighted the existence of a slightly positive, albeit not clinically significant, relationship. Higher exposure was required for efficacy in patients harboring the T315I mutation compared with those who did not. The exposure-safety relationship analysis showed no apparent association between exposure and adverse events of interest over the broad range of exposure or dose levels investigated. Asciminib has also been shown to have no clinically relevant effect on cardiac repolarization. Here, we review the clinical pharmacology data available to date for asciminib that supported its clinical development program and regulatory applications.

Dose Justification for Asciminib in Patients with Philadelphia Chromosome-Positive Chronic Myeloid Leukemia with and Without the T315I Mutation

BACKGROUND AND OBJECTIVE

Asciminib is approved in patients with Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase (Ph+ CML-CP) treated with ≥ 2 prior tyrosine kinase inhibitors. Here, we aimed to demonstrate similarity in efficacy/safety of asciminib 80 mg once daily (q.d.) versus 40 mg twice daily (b.i.d.) in patients with CML-CP without T315I mutation and support the use of the 200-mg b.i.d. dosage in patients harboring T315I, using model-informed drug development.

METHODS

Data were collected from 199 patients in the phase I (NCT02081378; 10-200 mg b.i.d. or 10-400 mg q.d.) and 154 patients in the phase III (NCT03106779; 40 mg b.i.d.) studies. Evaluations were based on population pharmacokinetics (PopPK) and exposure-response (efficacy/safety) analyses.

RESULTS

PopPK showed comparable exposure (area under the curve, AUC0-24h) for 40 mg b.i.d. and 80 mg q.d. (12,638 vs 12,646 ng*h/mL); average maximum and minimum plasma concentrations for 80 mg q.d. were 1.61- and 0.72-fold those of 40 mg b.i.d., respectively. Exposure-response analyses predicted similar major molecular response rates for 40 mg b.i.d. and 80 mg q.d. (Week 24: 27.6% vs 24.8%; Week 48: 32.3% vs 30.6%). Results also established adequacy of 200 mg b.i.d. in patients with T315I mutation (Week 24: 20.7%; Week 48: 23.7%), along with a similar safety profile for all dose regimens.

CONCLUSIONS

Similarity between 40 mg b.i.d. and 80 mg q.d. regimens was investigated, demonstrating similar and substantial efficacy with well-tolerated safety in patients without T315I mutation. The 200-mg b.i.d. dose was deemed safe and effective for patients with T315I mutation.

Real-World Disproportionality Analysis of the Food and Drug Administration Adverse Event Reporting System Database for Asciminib

INTRODUCTION

Asciminib is primarily utilized for treating Philadelphia chromosome-positive chronic myeloid leukemia in its chronic phase among patients harboring the T315I mutation or those who have been previously treated with at least two tyrosine kinase inhibitors. The safety profile of asciminib across a broad patient population over an extended timeframe remains unverified. This study uses a real-world pharmacovigilance database to evaluate the adverse events (AEs) linked with asciminib, providing valuable insights for clinical drug safety.

METHODS

Data from the FDA Adverse Event Reporting System (FAERS) database, spanning from October 2021 to December 2023, served as the basis for this analysis. The extent of disproportional events was assessed using sophisticated metrics such as the reporting odds ratio, proportional reporting ratio, information component, and empirical Bayesian geometric mean.

RESULTS

Within the specified period, the FAERS database documented 3,913,574 AE reports, with asciminib being associated with 966 incidents. Reactions to asciminib spanned 27 system organ categories. Utilizing four distinct analytical algorithms, 663 significant preferred terms exhibiting disproportional frequencies were identified. Notably, this investigation uncovered 26 significant AEs linked to off-label asciminib use, encompassing conditions such as gynecomastia, nephrotic syndrome, orchitis, pyelonephritis, hepatotoxicity, and pancreatitis. The median onset time for asciminib-related AEs was 52.5 days, ranging from 17 to 122.75 days.

CONCLUSION

The study sheds light on additional potential AEs associated with asciminib use, warranting further research to confirm these findings.

Effect of Hepatic and Renal Impairment on the Pharmacokinetics of Dersimelagon (MT-7117), an Oral Melanocortin-1 Receptor Agonist

Dersimelagon is an orally administered selective melanocortin-1 receptor agonist being investigated for treatment of erythropoietic protoporphyria, X-linked protoporphyria, and diffuse cutaneous systemic sclerosis. Dersimelagon is extensively metabolized in the liver, and potential recipients may have liver dysfunction. Further, effects of renal impairment on pharmacokinetic properties should be established in drugs intended for chronic use. Two separate studies (ClinicalTrials.gov: NCT04116476; NCT04656795) evaluated the effects of hepatic and renal impairment on dersimelagon pharmacokinetics, safety, and tolerability. Participants with mild (n = 7) or moderate (n = 8) hepatic impairment or normal hepatic function (n = 8) received a single oral 100-mg dersimelagon dose. Participants with mild (n = 8), moderate (n = 8), or severe (n = 8) renal impairment or normal renal function (n = 8) received a single 300-mg dose. Systemic exposure to dersimelagon was comparable with mild hepatic impairment but higher with moderate hepatic impairment (maximum observed plasma concentration, 1.56-fold higher; area under the plasma concentration-time curve from time 0 extrapolated to infinity, 1.70-fold higher) compared with normal hepatic function. Maximum observed plasma concentration and area under the plasma concentration-time curve from time 0 extrapolated to infinity were similar with moderate renal impairment but higher with mild (1.86- and 1.87-fold higher, respectively) and severe (1.17- and 1.45-fold higher, respectively) renal impairment versus normal renal function. Dersimelagon was generally well tolerated.

High Efficacy and Safety of Asciminib in a Chronic Myeloid Leukemia Patient with Chronic Kidney Disease Following Renal Transplantation

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm driven by the BCR::ABL1 tyrosine kinase. Tyrosine kinase inhibitors (TKIs) have been established as standard therapies for CML. However, some CML patients experience TKI intolerance. Asciminib was approved for CML patients either intolerant or refractory to TKI therapy. We herein report a 63-year-old CML patient who underwent renal transplantation and exhibited TKI intolerance. He was switched to asciminib, which achieved a deep molecular response without exacerbation of the renal function. Our experience revealed that asciminib is effective and safe for CML patients complicated with chronic kidney disease.

Clinical pharmacokinetics and drug-drug interactions of tyrosine-kinase inhibitors in chronic myeloid leukemia: A clinical perspective

In the past decade, numerous tyrosine kinase inhibitors (TKIs) have been introduced in the treatment of chronic myeloid leukemia. Given the significant interpatient variability in TKIs pharmacokinetics, potential drug-drug interactions (DDIs) can greatly impact patient therapy. This review aims to discuss the pharmacokinetic characteristics of TKIs, specifically focusing on their absorption, distribution, metabolism, and excretion profiles. Additionally, it provides a comprehensive overview of the utilization of TKIs in special populations such as the elderly, children, and patients with liver or kidney dysfunction. We also highlight known or suspected DDIs between TKIs and other drugs, highlighting various clinically relevant interactions. Moreover, specific recommendations are provided to guide haemato-oncologists, oncologists, and clinical pharmacists in managing DDIs during TKI treatment in daily clinical practice.

Activation/Inactivation of Anticancer Drugs by CYP3A4: Influencing Factors for Personalized Cancer Therapy

Cytochrome P450 3A4 (CYP3A4), one of the most important members of the cytochrome P450 subfamily, is a crucial catalyst in the metabolism of numerous drugs. As it catalyzes numerous processes for drug activation or inactivation, the pharmacological activities and clinical outcomes of anticancer drugs metabolized by CYP3A4 are highly dependent on the enzyme's activity and expression. Due to the complexity of tumor microenvironments and various influencing factors observed in human in vitro models and clinical studies, the pharmacokinetics of most anticancer drugs are influenced by the extent of induction or inhibition of CYP3A4-mediated metabolism, and these details are not fully recognized and highlighted. Therefore, this interindividual variability due to genetic and nongenetic factors, together with the narrow therapeutic index of most anticancer drugs, contributes to their unique set of exposures and responses, which have important implications for achieving the expected efficacy and minimizing adverse events of chemotherapy for cancer in individuals. To elucidate the mechanisms of CYP3A4-mediated activation/inactivation of anticancer drugs associated with personalized therapy, this review focuses on the underlying determinants that contribute to differences in CYP3A4 metabolic activity and provides a comprehensive and valuable overview of the significance of these factors, which differs from current considerations for dosing regimens in cancer therapy. We also discuss knowledge gaps, challenges, and opportunities to explore optimal dosing regimens for drug metabolic activation/inactivation in individual patients, with particular emphasis on pooling and analyzing clinical information that affects CYP3A4 activity. SIGNIFICANCE STATEMENT: This review focuses on anticancer drugs that are activated/deactivated by CYP3A4 and highlights outstanding factors affecting the interindividual variability of CYP3A4 activity in order to gain a detailed understanding of CYP3A4-mediated drug metabolism mechanisms. A systematic analysis of available information on the underlying genetic and nongenetic determinants leading to variation in CYP3A4 metabolic activity to predict therapeutic response to drug exposure, maximize efficacy, and avoid unpredictable adverse events has clinical implications for the identification and development of CYP3A4-targeted cancer therapeutics.

Population Pharmacokinetics of Asciminib in Tyrosine Kinase Inhibitor-Treated Patients with Philadelphia Chromosome-Positive Chronic Myeloid Leukemia in Chronic and Acute Phases

BACKGROUND

Asciminib, a first-in-class, highly potent and specific ABL/BCR-ABL1 inhibitor, has shown superior efficacy compared to bosutinib in patients with Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase, treated with two or more tyrosine kinase inhibitors. This study aimed to describe pharmacokinetic (PK) properties of asciminib and to identify clinically relevant covariates impacting its exposure.

METHODS

A population PK (PopPK) model was developed using a two-compartment model with delayed first-order absorption and elimination. The analysis included PK data from two clinical studies (Phases 1 and 3) involving 353 patients, with total daily dose of asciminib in the range of 20-400 mg.

RESULTS

The nominal total daily dose was incorporated as a structural covariate on clearance (CL), and body weight (BW) was included as a structural covariate via allometric scaling on CL and central volume. Renal function and formulation were included as statistically significant covariates on CL and absorption (k_a), respectively. The simulation results revealed a modest but clinically non-significant effect of baseline BW and renal function on k_a. Correlations between covariates, such as baseline demographics and disease characteristics, heavy smoking status, hepatic function, and T315I mutation status, were not statistically significant with respect to CL, and they were not incorporated in the final model. Additionally, the final model-based simulations demonstrated comparable exposure and CL for asciminib 40 mg twice daily and 80 mg once daily (an alternative regimen not studied in the Phase 3 trial), as well as similar PK properties in patients with and without the T315I mutation.

CONCLUSIONS

The final PopPK model adequately characterized the PK properties of asciminib and assessed the impact of key covariates on its exposure. The model corroborates the use of the approved asciminib dose of 80 mg total daily dose as 40 mg twice daily, and supports the use of 80 mg once daily as an alternative dose regimen to facilitate patient's compliance. TRIAL REGISTRATION NUMBER [DATE OF REGISTRATION]: First-in-human (CABL001X2101, Phase 1), ClinicalTrials.gov identifier: NCT02081378 [28 February 2014]; ASCEMBL (CABL001A2301, Phase 3), ClinicalTrials.gov identifier: NCT03106779 [10 April 2017].

An evaluation of asciminib for patients with chronic myeloid leukemia previously treated with ≥2 Tyrosine Kinase Inhibitors

INTRODUCTION

: To date, five tyrosine kinase inhibitors (TKIs) are available for treating chronic myeloid leukemia (CML) patients in clinical practice. Despite this, a significant proportion of patients will ultimately develop failure to approved TKIs due to intolerance or resistance. Consequently, new treatment approaches are still required in this unmet clinical need. Asciminib, a first-in-class BCR::ABL1 inhibitor Specifically Targeting the ABL Myristoyl Pocket (STAMP), has the potential to overcome resistance/intolerance to prior TKI treatment.

AREAS COVERED

This review will cover the mechanism of action, pharmacokinetic profile and clinical data of asciminib based on available information from laboratory studies, clinical trials and real world evidence.

EXPERT OPINION

Recent approval of asciminib will require positioning of this drug in the treatment algorithm of CML patients failing initial TKI therapy. Available data support the lack of cross-intolerance of asciminib with other TKIs and its favorable cardiovascular toxicity profile. In addition, asciminib has demonstrated considerable efficacy in CML patients who have failed at least two TKIs, although preliminary data suggest that this efficacy may be lower in those previously exposed to ponatinib. The introduction of asciminib in clinical practice may represent an important step forward in the management of CML.

Asciminib: new therapeutic option in chronic phase CML with treatment failure

Asciminib, a first-in-class allosteric inhibitor of BCR::ABL1 kinase activity, is now approved for the treatment of chronic phase CML patients who failed 2 lines of therapy or in patients with the T315I mutation. Promising attributes include high specificity and potency against BCR::ABL1, activity against most kinase domain mutations, and potential for combination therapy with ATP-competitive tyrosine kinase inhibitors (TKIs). Clinicians now have expanded third-line options which in most cases will involve a choice between asciminib and ponatinib.

Pharmacokinetic drug interactions of asciminib with the sensitive cytochrome P450 probe substrates midazolam, warfarin, and repaglinide in healthy participants

Asciminib, a first‐in‐class BCR‐ABL1 inhibitor that works by Specifically Targeting the ABL Myristoyl Pocket (STAMP), is a new treatment option for patients with chronic myeloid leukemia who no longer benefit from currently approved tyrosine kinase inhibitors. In vitro, asciminib reversibly inhibits cytochrome P450 (CYP) 3A4/5, CYP2C9, and CYP2C8. This phase I, open‐label, two‐stage study in healthy participants evaluated the effect of asciminib (40 mg b.i.d. at steady‐state) as a potential perpetrator on single‐dose pharmacokinetics of a two‐drug cocktail containing midazolam (CYP3A substrate) and warfarin (CYP2C9 substrate) in stage 1 (n = 22), and of repaglinide (CYP2C8 substrate) in stage 2 (n = 25). For midazolam plus asciminib versus midazolam, geometric mean (G_mean) ratios (90% confidence interval) for midazolam area under the curve from zero to infinity (AUC_inf) and maximum plasma concentration (C_max) were 1.28 (1.15, 1.43) and 1.11 (0.96, 1.28), respectively. For warfarin plus asciminib versus warfarin, G_mean ratios for S‐warfarin AUC_inf and C_max were 1.41 (1.37, 1.45) and 1.08 (1.04, 1.13), respectively. Results for R‐warfarin were in line with those for S‐warfarin. For repaglinide plus asciminib versus repaglinide, G_mean ratios for AUC_inf and C_max were 1.08 (1.02, 1.14) and 1.14 (1.01, 1.28), respectively. The treatments were generally well tolerated, and the asciminib safety profile was consistent with previous studies of asciminib in the absence of probe substrates. Overall, the results indicate that asciminib (40 mg b.i.d.) is a weak inhibitor of CYP3A and CYP2C9 and has no meaningful effect on CYP2C8.

Asciminib: First Approval

Asciminib (Scemblix^®) is an orally administered, small molecule, selective allosteric inhibitor that targets the myristoyl pocket of the BCR-ABL1 tyrosine kinase and is being developed by Novartis for the treatment of haematological malignancies, including Philadelphia chromosome-positive (Ph+) chronic myeloid leukaemia (CML). The drug is active against a number of the single catalytic-site mutations, such as T315I, that confer resistance to conventional tyrosine kinase inhibitors (TKIs) that bind to the ATP-binding site of BCR-ABL1. In October 2021, asciminib monotherapy was granted accelerated approval for the treatment of adults with Ph+ CML in chronic phase (CML-CP), previously treated with ≥ 2 TKIs, and full approval for the treatment of adults with Ph+ CML-CP with the T315I mutation. The drug is under regulatory review for use as monotherapy in CML in the EU, and is in phase 1-3 development exploring its potential in first-line, later-line and paediatric patients with CML. This article summarizes the milestones in the development of asciminib leading to this first approval for the treatment of adults with Ph+ CML-CP, previously treated with ≥ 2 TKIs, and Ph+ CML-CP with the T315I mutation.

Gene Transcription as a Therapeutic Target in Leukemia

Blood malignancies often arise from undifferentiated hematopoietic stem cells or partially differentiated stem-like cells. A tight balance of multipotency and differentiation, cell division, and quiescence underlying normal hematopoiesis requires a special program governed by the transcriptional machinery. Acquisition of drug resistance by tumor cells also involves reprogramming of their transcriptional landscape. Limiting tumor cell plasticity by disabling reprogramming of the gene transcription is a promising strategy for improvement of treatment outcomes. Herein, we review the molecular mechanisms of action of transcription-targeted drugs in hematological malignancies (largely in leukemia) with particular respect to the results of clinical trials.