Population Pharmacokinetics and Exposure-Response Relationship of Carfilzomib in Patients With Multiple Myeloma

Target trial emulation of carfilzomib safety among patients with relapsed/refractory multiple myeloma using a nationwide observational data in Korea

PURPOSE

Carfilzomib, commonly used for relapsed/refractory multiple myeloma (RRMM), has been associated with various adverse events in randomized controlled trials (RCTs). However, real-world safety data for a more diverse population are needed, as carfilzomib received expedited approval. This study aimed to evaluate carfilzomib's safety in Korea by comparing new users of KRd (carfilzomib, lenalidomide, and dexamethasone) to Rd (lenalidomide and dexamethasone) using a nationwide administrative claims database.

METHODS

The retrospective cohort study utilized target trial emulation, focusing on adverse events in various organ systems similar to the ASPIRE trial.

RESULTS

This study included 4,580 RRMM patients between 2007 and 2020, and the KRd group showed significantly higher risks of hematologic adverse events (anemia, neutropenia, thrombocytopenia) and some non-hematologic adverse events (cough, hypokalemia, constipation, hypertension, heart failure) compared to the Rd group. Among non-hematologic adverse events, cardiovascular events (heart failure [HR 2.04; 95% CI 1.24-3.35], hypertension [HR 1.58; 95% CI 1.15-2.17]) had the highest risk in the KRd group.

CONCLUSION

The safety profile of carfilzomib in Korean patients was similar to previous RCTs. Therefore, caution should be exercised when using carfilzomib in Asian individuals with RRMM due to the increased risk of cardiovascular adverse events.

Population Pharmacokinetics and Pharmacodynamics of Carfilzomib in Combination with Rituximab, Ifosfamide, Carboplatin, and Etoposide in Adult Patients with Relapsed/Refractory Diffuse Large B Cell Lymphoma

BACKGROUND

In patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL), salvage chemotherapy regimens (e.g., rituximab, ifosfamide, carboplatin, and etoposide, R-ICE) yield poor outcomes. Carfilzomib, an irreversible proteasome inhibitor, can overcome acquired rituximab-chemotherapy resistance and, when combined with R-ICE, improves outcomes in patients with R/R DLBCL.

OBJECTIVE

This analysis aimed to develop a population pharmacokinetic/pharmacodynamic (PK/PD) model for carfilzomib in R/R DLBCL patients.

PATIENTS AND METHODS

In a single-center, open-label, prospective phase 1 study, patients received carfilzomib (10, 15, or 20 mg/m2) on days 1, 2, 8, and 9, and standard doses of R-ICE on days 3-6 every 21 days (maximum of three cycles). Carfilzomib plasma concentrations up to 24 h postinfusion were measured by liquid chromatography coupled with tandem mass spectrometry. Proteasome activity (PD biomarker) in peripheral blood mononuclear cells was assessed on days 1-2 with sparse sampling. PK/PD models were developed using NONMEM v7.4.1 interfaced with Finch Studio v1.1.0 and PsN v4.7.0. Model selection was guided by objective function value, goodness-of-fit, and visual predictive checks. Stepwise covariate modeling was used for covariate selection.

RESULTS

Twenty-eight patients were enrolled in the PK/PD analysis, from whom 217 PK samples and 127 PD samples were included. Carfilzomib PK was best described by a two-compartment model with linear disposition (typical total clearance of 133 L/h). Proteasome activity was best characterized using a turnover model with irreversible inactivation. All parameters were estimated with good precision. No statistically significant covariates were identified.

CONCLUSIONS

A validated population-based PK/PD model of carfilzomib was developed successfully. Further research is needed to identify sources of variability in response to treatment with carfilzomib in combination with R-ICE.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier number NCT01959698.

Mechanistic Pharmacokinetic/Pharmacodynamic Modeling in Support of a Patient-Convenient, Longer Dosing Interval for Carfilzomib, a Covalent Inhibitor of the Proteasome

BACKGROUND

Carfilzomib is an irreversible second-generation proteasome inhibitor that has a short elimination half-life but much longer pharmacodynamic (PD) effect based on its irreversible mechanism of action, making it amenable to longer dosing intervals. A mechanistic pharmacokinetic/pharmacodynamic (PK/PD) model was built using a bottom-up approach, based on the mechanism of action of carfilzomib and the biology of the proteasome, to provide further evidence of the comparability of once-weekly and twice-weekly dosing.

METHODS

The model was qualified using clinical data from the phase III ENDEAVOR study, where the safety and efficacy of bortezomib (a reversible proteasome inhibitor) and carfilzomib were compared. Simulations were performed to compare the average proteasome inhibition across five cycles of treatment for the 20/70 mg/m² once-weekly (70 QW) and 20/56 mg/m² twice-weekly (56 BIW) regimens.

RESULTS

Results indicated that while 70 QW had a higher maximum concentration (C_max) and lower steady-state area under the concentration-time curve (AUC) than 56 BIW, the average proteasome inhibition after five cycles of treatment between the regimens was comparable. Presumably, the higher C_max of carfilzomib from 70 QW compensates for the lower overall AUC compared with 56 BIW, and hence 70 QW is expected to have comparable proteasome inhibition, and therefore comparable efficacy, to 56 BIW. The comparable model-predicted proteasome inhibition between 70 QW and 56 BIW also translated to comparable clinical response, in terms of overall response rate and progression-free survival.

CONCLUSION

This work provides a framework for which mechanistic PK/PD modeling can be used to guide optimization of dosing intervals for therapeutics with significantly longer PD effects than PK, and help further justify patient-convenient, longer dosing intervals.

Systems level profiling of chemotherapy-induced stress resolution in cancer cells reveals druggable trade-offs

Cancer cells can survive chemotherapy-induced stress, but how they recover from it is not known. Using a temporal multiomics approach, we delineate the global mechanisms of proteotoxic stress resolution in multiple myeloma cells recovering from proteasome inhibition. Our observations define layered and protracted programs for stress resolution that encompass extensive changes across the transcriptome, proteome, and metabolome. Cellular recovery from proteasome inhibition involved protracted and dynamic changes of glucose and lipid metabolism and suppression of mitochondrial function. We demonstrate that recovering cells are more vulnerable to specific insults than acutely stressed cells and identify the general control nonderepressable 2 (GCN2)-driven cellular response to amino acid scarcity as a key recovery-associated vulnerability. Using a transcriptome analysis pipeline, we further show that GCN2 is also a stress-independent bona fide target in transcriptional signature-defined subsets of solid cancers that share molecular characteristics. Thus, identifying cellular trade-offs tied to the resolution of chemotherapy-induced stress in tumor cells may reveal new therapeutic targets and routes for cancer therapy optimization.

Overview of Current Targeted Anti-Cancer Drugs for Therapy in Onco-Hematology

The upgraded knowledge of tumor biology and microenviroment provides information on differences in neoplastic and normal cells. Thus, the need to target these differences led to the development of novel molecules (targeted therapy) active against the neoplastic cells' inner workings. There are several types of targeted agents, including Small Molecules Inhibitors (SMIs), monoclonal antibodies (mAbs), interfering RNA (iRNA) molecules and microRNA. In the clinical practice, these new medicines generate a multilayered step in pharmacokinetics (PK), which encompasses a broad individual PK variability, and unpredictable outcomes according to the pharmacogenetics (PG) profile of the patient (e.g., cytochrome P450 enzyme), and to patient characteristics such as adherence to treatment and environmental factors. This review focuses on the use of targeted agents in-human phase I/II/III clinical trials in cancer-hematology. Thus, it outlines the up-to-date anticancer drugs suitable for targeted therapies and the most recent finding in pharmacogenomics related to drug response. Besides, a summary assessment of the genotyping costs has been discussed. Targeted therapy seems to be an effective and less toxic therapeutic approach in onco-hematology. The identification of individual PG profile should be a new resource for oncologists to make treatment decisions for the patients to minimize the toxicity and or inefficacy of therapy. This could allow the clinicians to evaluate benefits and restrictions, regarding costs and applicability, of the most suitable pharmacological approach for performing a tailor-made therapy.

Analysis of carfilzomib cardiovascular safety profile across relapsed and/or refractory multiple myeloma clinical trials

Carfilzomib is a selective proteasome inhibitor approved for the treatment of relapsed and/or refractory multiple myeloma (RRMM). It has significantly improved outcomes, including overall survival (OS), and shown superiority vs standard treatment with lenalidomide plus dexamethasone and bortezomib plus dexamethasone. The incidence rate of cardiovascular (CV) events with carfilzomib treatment has varied across trials. This analysis evaluated phase 1-3 trials with >2000 RRMM patients exposed to carfilzomib to describe the incidence of CV adverse events (AEs). In addition, the individual CV safety data of >1000 patients enrolled in the carfilzomib arm of phase 3 studies were compared with the control arms to assess the benefit-risk profile of carfilzomib. Pooling data across carfilzomib trials, the CV AEs (grade ≥3) noted included hypertension (5.9%), dyspnea (4.5%), and cardiac failure (4.4%). Although patients receiving carfilzomib had a numeric increase in the rates of any-grade and grade ≥3 cardiac failure, dyspnea, and hypertension, the frequency of discontinuation or death due to these cardiac events was low and comparable between the carfilzomib and control arms. Serial echocardiography in a blinded cardiac substudy showed no objective evidence of cardiac dysfunction in the carfilzomib and control arms. Moreover, carfilzomib had no significant effect on cardiac repolarization. Our results, including the OS benefit, showed that the benefit of carfilzomib treatment in terms of reducing progression or death outweighed the risk for developing cardiac failure or hypertension in most patients. Appropriate carfilzomib administration and risk factor management are recommended for elderly patients and patients with underlying risk factors.

Preclinical comparison of proteasome and ubiquitin E1 enzyme inhibitors in cutaneous squamous cell carcinoma: the identification of mechanisms of differential sensitivity

Proteasome inhibitors have distinct properties and the biochemical consequences of suppressing ubiquitin E1 enzymes and the proteasome differ. We compared the effects of the proteasome inhibitors bortezomib, ixazomib and carfilzomib and the ubiquitin E1 enzyme inhibitor MLN7243/TAK-243 on cell viability and cell death in normal keratinocytes and cutaneous squamous cell carcinoma (cSCC) cell lines. The effects of both a pulse of treatment and more extended incubation were investigated. This is relevant to directly-delivered therapy (topical treatment/intratumoral injection) where the time of exposure can be controlled and a short exposure may better reflect systemically-delivered inhibitor pharmacokinetics. These agents can selectively kill cSCC cells but there are variations in the pattern of cSCC cell line sensitivity/resistance. Variations in the responses to proteasome inhibitors are associated with differences in the specificity of the inhibitors for the three proteolytic activities of the proteasome. There is greater selectivity for killing cSCC cells compared to normal keratinocytes with a pulse of proteasome inhibitor treatment than with a more extended exposure. We provide evidence that c-MYC-dependent NOXA upregulation confers susceptibility to a short incubation with proteasome inhibitors by priming cSCC cells for rapid BAK-dependent death. We observed that bortezomib-resistant cSCC cells can be sensitive to MLN7243-induced death. Low expression of the ubiquitin E1 UBA1/UBE1 participates in conferring susceptibility to MLN7243 by increasing sensitivity to MLN7243-mediated attenuation of ubiquitination. This study supports further investigation of the potential of proteasome and ubiquitin E1 inhibition for cSCC therapy. Direct delivery of inhibitors could facilitate adequate exposure of skin cancers.

Pharmacokinetics of carfilzomib in patients with advanced malignancies and varying degrees of hepatic impairment: an open-label, single-arm, phase 1 study

BACKGROUND

Carfilzomib is approved in the United States and Europe for treatment of relapsed or refractory multiple myeloma (MM). This study evaluated pharmacokinetics (PK) and safety of carfilzomib in patients with relapsed or progressive advanced malignancies and varying degrees of impaired hepatic function.

METHODS

Patients with normal hepatic function (normal) or hepatic impairment (mild, moderate, or severe) received carfilzomib infusion in 28-day cycles. The primary objective was to assess the influence of hepatic impairment on carfilzomib PK following 27 and 56 mg/m² doses.

RESULTS

The majority of patients enrolled in this study had solid tumors (n = 44) vs. MM (n = 2) since patients with multiple myeloma do not tend to have severe hepatic impairment in the same way as patients with solid tumors. A total of 11 normal and 17 mild, 14 moderate, and 4 severe hepatic impairment patients were enrolled. Compared with patients with normal hepatic function, patients with mild and moderate hepatic impairment had 44 and 26% higher carfilzomib AUC_0-last, respectively (27 mg/m² dose); increases at the 56 mg/m² dose were 45 and 21%, respectively. Considerable PK variability (% coefficient of variation in AUC ≤100%) was discerned and no consistent trend of increasing exposure resulting from increasing hepatic impairment severity (moderate vs. mild) was seen. The observed adverse event (AE) profile in patients of mostly solid tumors was consistent with the known safety profile of carfilzomib, with the exception of an increased frequency of AEs consistent with hepatic function abnormalities.

CONCLUSIONS

In this population of primarily advanced solid tumor patients, patients with mild and moderate hepatic impairment had approximately 20-50% higher carfilzomib AUC vs. normal hepatic function patients. These increases are unlikely to be clinically significant, in light of the intrinsic PK variability and exposure-response relationship of carfilzomib. Trial registration http://clinicaltrials.gov NCT01949545; date of registration: September 6, 2013.

Pharmacokinetics and safety of carfilzomib in patients with relapsed multiple myeloma and end-stage renal disease (ESRD): an open-label, single-arm, phase I study

Purpose

The pharmacokinetics (PK) of carfilzomib have been previously studied in multiple myeloma patients with varying degrees of renal impairment (normal, mild, moderate, severe, and end-stage renal disease [ESRD]) at doses of 15 and 20 mg/m². This study evaluated carfilzomib PK at higher doses of 27 and 56 mg/m² in normal renal function and ESRD patients.

Methods

Patients received carfilzomib on two consecutive days/week for 3 weeks every 28-day cycle: 20 mg/m² (cycle 1 day 1–2), escalated to 27 mg/m² on cycle 1 day 8; if tolerated, 56 mg/m² starting cycle 2 day 1. The primary objective was PK assessment with safety/tolerability and response rate as secondary and exploratory objectives, respectively.

Results

26 patients were enrolled (15 normal, 11 ESRD). There was a trend toward higher area under the concentration time curve (AUC) and maximum concentration in ESRD versus normal renal function patients; however, high interpatient PK variability was discerned. Relative to patients with normal renal function, ESRD patients showed 33% higher AUC. Overall response rate was 43% for the normal renal function and 60% for the ESRD groups. Safety findings were generally similar between the two groups and consistent with the known safety profile of carfilzomib in multiple myeloma patients.

Conclusion

There were no meaningful differences in PK between patients with normal renal function and ESRD in light of carfilzomib exposure–response relationships. These results continue to support dosing recommendation that no starting dose adjustment of carfilzomib appears warranted in patients with baseline renal impairment.