A pharmacokinetics and safety phase 1/1b study of oral ixazomib in patients with multiple myeloma and severe renal impairment or end-stage renal disease requiring haemodialysis

Phase I study of TQB3602, an oral proteasome inhibitor, in relapsed and refractory multiple myeloma

OBJECTIVE

TQB3602 is a novel orally bioavailable proteasome inhibitor. This study is the first-in-human phase I clinical trial to evaluate the safety, tolerability, pharmacokinetics, and preliminary efficacy of TQB3602 in relapsed/refractory multiple myeloma (RRMM).

METHODS

This is a multicenter phase I clinical trial consisting of the 3+3 dose-escalation phase and dose expansion phase. Patients with MM who have received ≥2 prior antimyeloma therapies were enrolled. TQB3602 is administered at a dose of 0.5~7mg on days 1, 8, 15 in 28-day cycle.

RESULTS

Twenty-five RRMM patients who relapsed or failed ≥2 lines of therapies were enrolled in the dose escalation phase. Two patients in the 7.0 mg dose group developed dose-limiting toxicity events (one with grade 2 peripheral neuropathy [PN] complicated by pain and one with diarrhea and abdominal pain), leading to a maximum tolerated dose of 6.0 mg. Any-grade adverse events (AEs) occurred in 24 (96.0%) patients, while grade ≥3 AEs occurred in 13 (52.0%). The most common grade ≥3 AEs was anemia (6, 24.0%). The incidence rate of PN was 16% with no grade ≥3 PN occurred. TQB3602 was rapidly absorbed, resulting in a time-to-plasma peak concentration of 0.8-1.5 h. The mean half-life was approximately 82 h. The AUClast and Cmax were approximately 1.9 times higher on day 15 than on day 1. Among 22 response-evaluable patients, 63.7% achieved stable disease or better.

CONCLUSIONS

TQB3602 is well tolerated, with a favorable neurotoxicity profile, and has shown preliminary efficacy in patients with RRMM. The anticipated therapeutic dose was 6 mg and was adopted for an ongoing dose-expansion phase.

Practical management of disease-related manifestations and drug toxicities in patients with multiple myeloma

Multiple myeloma (MM) is a very heterogeneous disease with multiple symptoms and clinical manifestations. MM affects mainly elderly patients and is difficult to manage in the presence of comorbidities, polypharmacy, frailty and adverse events of disease-targeted drugs. The rapid changes in MM treatment resulting from constant innovations in this area, together with the introduction of numerous new drugs with distinct mechanisms of action and toxicity profiles, have led to an increased complexity in the therapeutic decision-making and patient management processes. The prolonged exposure to novel agents, sometimes in combination with conventional therapies, makes this management even more challenging. A careful balance between treatment efficacy and its tolerability should be considered for every patient. During treatment, a close monitoring of comorbidities, disease-related manifestations and treatment side effects is recommended, as well as a proactive approach, with reinforcement of information and patient awareness for the early recognition of adverse events, allowing prompt therapeutic adjustments. In this review, we discuss various issues that must be considered in the treatment of MM patients, while giving practical guidance for monitoring, prevention and management of myeloma-related manifestations and treatment-related toxicities.

Proteasome inhibition in combination with immunotherapies: State-of-the-Art in multiple myeloma

Multiple myeloma (MM) is a malignant plasma cell disorder accounting for around 1.8% of all neoplastic diseases. Nowadays, clinicians have a broad arsenal of drugs at their disposal for the treatment of MM, such as proteasome inhibitors, immunomodulatory drugs, monoclonal antibodies, bispecific antibodies, CAR T-cell therapies and antibody-drug conjugates. In this paper we briefly highlight essential clinical elements relating to proteasome inhibitors, such as bortezomib, carfilzomib and ixazomib. Studies suggest that the early use of immunotherapy may improve outcomes significantly. Therefore, in our review we specifically focus on the combination therapy of proteasome inhibitors with novel immunotherapies and/or transplant. A high number of patients develop PI resistance. Thus, we also review new generation PIs, such as marizomib, oprozomib (ONX0912) and delanzomib (CEP-18770) and their combinations with immunotherapies.

Management of multiple myeloma-related renal impairment: recommendations from the International Myeloma Working Group

Here, the International Myeloma Working Group (IMWG) updates its clinical practice recommendations for the management of multiple myeloma-related renal impairment on the basis of data published until Dec 31, 2022. All patients with multiple myeloma and renal impairment should have serum creatinine, estimated glomerular filtration rate, and free light chains (FLCs) measurements together with 24-h urine total protein, electrophoresis, and immunofixation. If non-selective proteinuria (mainly albuminuria) or involved serum FLCs value less than 500 mg/L is detected, then a renal biopsy is needed. The IMWG criteria for the definition of renal response should be used. Supportive care and high-dose dexamethasone are required for all patients with myeloma-induced renal impairment. Mechanical approaches do not increase overall survival. Bortezomib-based regimens are the cornerstone of the management of patients with multiple myeloma and renal impairment at diagnosis. New quadruplet and triplet combinations, including proteasome inhibitors, immunomodulatory drugs, and anti-CD38 monoclonal antibodies, improve renal and survival outcomes in both newly diagnosed patients and those with relapsed or refractory disease. Conjugated antibodies, chimeric antigen receptor T-cells, and T-cell engagers are well tolerated and effective in patients with moderate renal impairment.

Partnering With All Patients: Ensuring Shared Decision Making and Evidence-Based Management for Underrepresented Groups With Multiple Myeloma

Several landmark therapeutic advances in multiple myeloma (MM) have led to an unprecedented number of options available to patients and their physicians as shared decision making is attempted. A myriad of factors need to be considered to ensure that patient-, disease-, and treatment-related factors are addressed to arrive at the most appropriate choice for patients at that time in their journey with myeloma. Some of these factors have traditionally remained underaddressed but have a clear association with patient outcomes, leading to underrepresented groups of patients with MM, including the elderly patients, racial-ethnic minorities, and those with specific advanced comorbidities, for example, renal insufficiency. Some of these factors may not be modifiable, but data suggest that they may give rise to implicit or explicit bias and affect treatment decisions. A growing body of literature is bringing these factors to light. However, their incorporation in day-to-day decision making for patients needs to be universal. It is imperative that prospective data are generated for all these and other underrepresented groups such that evidence-based medicine is applicable universally to all patients with MM, irrespective of clinical and sociodemographic factors.

Multiple myeloma with acute light chain cast nephropathy

Light chain cast nephropathy (LCCN) is a leading cause of acute kidney injury (AKI) in patients with multiple myeloma (MM) and is now defined as a myeloma defining event. While the long-term prognosis has improved with novel agents, short-term mortality remains significantly higher in patients with LCCN especially if the renal failure is not reversed. Recovery of renal function requires a rapid and significant reduction of the involved serum free light chain. Therefore, proper treatment of these patients is of the utmost importance. In this paper, we provide an algorithm for treatment of MM patients who present with biopsy-proven LCCN or in those where other causes of AKI have been ruled out. The algorithm is based on data from randomized trial whenever possible. When trial data is not available, our recommendations is based on non-randomized data and expert opinions on best practices. We recommend that all patients should enroll in a clinical trial if available prior to resorting to the treatment algorithm we outlined.

No needles needed: All-oral therapy options for relapsed and refractory multiple myeloma

Immense progress has been made for the treatment of multiple myeloma over the past two decades, with patient outcomes improving dramatically as a result. Patient quality of life, however, is constantly challenged by complications of the disease, side effects of therapy and the overall burden receiving continuous treatment. Compared to parenteral agents, all-oral regimens can provide logistically favorable alternatives and are associated with improved quality of life. Here, we review the currently available and investigational oral therapies for relapsed and refractory multiple myeloma and provide a practical clinical reference tool. We explore the factors that dictate the selection of therapy, such as prior drug refractoriness, disease biology and patient-specific considerations. Regimens with their respective supporting clinical data are organized by the degree of prior treatment, from lenalidomide-sensitive to heavily pretreated patients. We explore common challenges such as renal insufficiency and cytopenias. Lastly, we review investigational oral agents.

An update on the safety of ixazomib for the treatment of multiple myeloma

INTRODUCTION

Treatment options for multiple myeloma (MM) have rapidly expanded over the past few years with several newly approved drugs. While there is need to explore treatments that lead to longer responses and survival, special consideration should be given on reducing treatment burden, reducing toxicities, and improving quality of life. Ixazomib is the first oral proteasome inhibitor for the treatment of MM, combining clinical efficacy with a favorable safety profile.

AREAS COVERED

Here, we discuss the clinical efficacy and safety of ixazomib. Pharmacokinetic considerations, management of common toxicities, and the impact of the drug on the current and future treatment strategies are also discussed.

EXPERT OPINION

Ixazomib is an effective and welltolerated MM drug. It is also being studied in combination with other newer agents. It does not have long-term cumulative toxicities, and the most adverse events are mild and manageable. These findings, along with the ease of oral administration, make it a possible option for long-term treatment approaches for MM patients, as well as in the frail/elderly patient population.

Ixazomib combined with lenalidomide and dexamethasone chemotherapy for newly diagnosed multiple myeloma in China-Compared with bortezomib/lenalidomide/dexamethasone

BACKGROUND

To compare the response and safety of Ixazomib/Lenalidomide/Dexamethasone (IRd) and Bortezomib/Lenalidomide/Dexamethasone (VRd) treatment in newly diagnosed multiple myeloma (MM).

METHODS

This was a single-center retrospective analysis in Xiangtan Central Hospital. A total of 52 newly diagnosed MM patients from June 2019 to June 2021 were enrolled and divided into the IRd (n = 21) and VRd (n = 31) groups. After 4 cycles of chemotherapy, the best response and adverse events were recorded. Moreover, the progression-free survival (PFS) and overall survival (OS) were calculated.

RESULTS

Patients in IRd group and VRd group showed similar PFS (Log-rank p = 0.70), OS (Log-rank p = 0.61) and overall response rate (83.87% vs 90.48%, p = 0.803). In addition, patients in VRd group showed lower Eastern Cooperative Oncology Group scores (p = 0.047), and higher incidence of peripheral sensory neuropathy (0.00% vs 19.35%, p = 0.032) than that of patients in IRd group.

CONCLUSION

Compared to VRd regimen, IRd had the similar efficacy, better safety, and may be more convenient for patients with poor basic condition for newly diagnosed MM. This study provides an insight for physicians to use IRd as first-line treatment in MM.

An overview of treatment options for patients with relapsed/refractory multiple myeloma and renal impairment

Renal impairment (RI) is a relatively common complication of multiple myeloma, which increases in frequency as disease becomes more advanced and recovery of renal function becomes less likely as patients progress through lines of therapy. Clinical trials in the relapsed/refractory multiple myeloma (RRMM) setting have not uniformly included patients with RI or robustly reported their outcomes. Here, we review existing data among patients with RI and RRMM across drug classes (including immunomodulatory agents, proteasome inhibitors, monoclonal antibodies, antibody-drug conjugates, chimeric antigen receptor T-cell therapies, and exportin-1 inhibitor) to provide an improved understanding of available treatment options for this important population. We highlight data from pivotal clinical trials, including data relating to renal response (as defined by the International Myeloma Working Group) and discuss real-world experiences in patients with RI, where applicable. Despite substantial advances in RRMM treatment, the presence of RI remains associated with reduced overall survival. Consistent inclusion of patients with RI, and uniform reporting of their outcomes, should be encouraged in future prospective trials of treatments for RRMM.

Advances in the Treatment of Relapsed and Refractory Multiple Myeloma in Patients with Renal Insufficiency: Novel Agents, Immunotherapies and Beyond

BACKGROUND

Renal insufficiency is one of the most frequent complications in multiple myeloma. The incidence of renal insufficiency in patients with multiple myeloma ranges from 20% to 50%. Renal impairment in patients with multiple myeloma results primarily from the toxic effects of monoclonal light chains on the kidneys. Dehydration, hypercalcemia, hyperuricemia, the application of nephrotoxic NSARs, antibiotics, contrast agents, etc., all play a major role in the deterioration of renal function in patients with multiple myeloma. The diagnosis and treatment of these patients use an interdisciplinary approach in consultation with hematologist-oncologists, radiologists, nephrologists and intensive care specialists. Using new drugs in the treatment of patients with refractory/relapsed multiple myeloma and renal insufficiency markedly improves progression-free survival and overall survival in these patients.

CONCLUSIONS

New drugs have helped to widen the treatment options available for patients with renal impairment and refractory/relapsed multiple myeloma, since dose adjustments are unnecessary with carfilzomib as well as with panobinostat, elotuzumab, pomalidomide or daratumumab in patients with renal impairment. Several new substances for the treatment of refractory/relapsed multiple myeloma have been approved in the meantime, including belantamab mafodotin, selinexor, melflufen, venetoclax, CAR T-cell therapy and checkpoint inhibitors. Ongoing studies are investigating their administration in patients with renal impairment.

A pilot study of 3D tissue-engineered bone marrow culture as a tool to predict patient response to therapy in multiple myeloma

Cancer patients undergo detrimental toxicities and ineffective treatments especially in the relapsed setting, due to failed treatment attempts. The development of a tool that predicts the clinical response of individual patients to therapy is greatly desired. We have developed a novel patient-derived 3D tissue engineered bone marrow (3DTEBM) technology that closely recapitulate the pathophysiological conditions in the bone marrow and allows ex vivo proliferation of tumor cells of hematologic malignancies. In this study, we used the 3DTEBM to predict the clinical response of individual multiple myeloma (MM) patients to different therapeutic regimens. We found that while no correlation was observed between in vitro efficacy in classic 2D culture systems of drugs used for MM with their clinical efficacious concentration, the efficacious concentration in the 3DTEBM were directly correlated. Furthermore, the 3DTEBM model retrospectively predicted the clinical response to different treatment regimens in 89% of the MM patient cohort. These results demonstrated that the 3DTEBM is a feasible platform which can predict MM clinical responses with high accuracy and within a clinically actionable time frame. Utilization of this technology to predict drug efficacy and the likelihood of treatment failure could significantly improve patient care and treatment in many ways, particularly in the relapsed and refractory setting. Future studies are needed to validate the 3DTEBM model as a tool for predicting clinical efficacy.

Special Considerations for Supportive Care and Management of Complications in Elderly Patients With Multiple Myeloma

Multiple myeloma is a progressive and incurable hematologic malignancy. It is predominantly a disease of older individuals, with a third of these patients considered to be elderly. In recent years, there has been a focus and emphasis on identifying and stratifying patients based on their functional status and frailty. There are several hallmark complications of the disease-hypercalcemia, renal insufficiency, anemia, bone pain-along with thromboembolism and compromised immunity that are common in patients with multiple myeloma. Due to the wide range of patient ages and functional status, there are, accordingly, different considerations for management of the above complications based on numerous factors, including frailty status. This review focuses on considerations and management of common complications of multiple myeloma in elderly patients. These include renal failure, skeletal complications, anemia, thromboembolism, and infectious complications.

A comparison of the efficacy and safety of ixazomib and lenalidomide combined with dexamethasone in the treatment of multiple myeloma

OBJECTIVE

To explore the efficacy and safety of ixazomib and lenalidomide combined with dexamethasone (DXMS) in the treatment of multiple myeloma (MM).

METHODS

A total of 80 patients with newly diagnosed MM were randomly divided into the ID group (ixazomib + DXMS, n=40) and the RD group (lenalidomide + DXMS, n=40). All patients were given DXMS orally on the 1st, 8th, 15th, and 22nd day of the treatment cycle (20 mg each time). The patients in the ID group also received 4 mg of ixazomib citrate capsules orally on the 1st, 8th, and 15th day of the treatment cycle, whereas those in the RD group received 25 mg of lenalidomide capsules orally from the 1st to the 21st day of the treatment cycle continuously. The primary outcome measure was progression-free survival (PFS) within 5 years, and the secondary outcome measures were overall survival (OS), overall response rate (ORR), quality of life, and safety.

RESULTS

The median PFS and median OS in the ID group were similar to those in the RD group (30.03 and 50.21 months vs. 25.04 and 46.33 months, both P>0.05). The ID group had higher complete remission rate (13 cases vs. 5 cases, P<0.05), but similar ORR compared with the RD group (90.00% vs. 82.50%, P>0.05). After treatment, the pain intensity assessed by Numeric Rating Scale and the functional impairment measured by Karnofsky Performance Status Scale of the two groups were both relieved (both P<0.001), and no intergroup differences in these two markers were observed (both P>0.05). The incidence of grade 1-2 peripheral neuropathy in the ID group was higher than that in the RD group (30.00% vs. 20.00%, P=0.032). There were no differences in other adverse reactions between the two groups (all P>0.05).

CONCLUSION

Compared with the combination of lenalidomide and DXMS, ixazomib combined with DXMS can achieve higher complete remission rate and more improved PFS and OS in patients with newly diagnosed MM, which is a safe and effective method.

Outcomes of ixazomib/lenalidomide/dexamethasone for multiple myeloma: A multicenter retrospective analysis

OBJECTIVES

This study aimed to investigate real-world data of ixazomib plus lenalidomide and dexamethasone (IRd) therapy for patients with relapsed and refractory multiple myeloma (RRMM).

METHODS

We retrospectively analyzed 122 patients treated with IRd at 16 centers from May 2017 to January 2019 by using the Kansai Myeloma Forum database.

RESULT

At the start of IRd, the median age was 72 years, 66.7% of patients had IgG type, and the median number of prior therapies was 4, comprising bortezomib (85.4%) and lenalidomide (89.3%)-based regimens. Disease progression and adverse events accounted for treatment discontinuation in 46 and 32 patients, respectively. The median overall survival (OS) was not reached, and the median progression-free survival (PFS) was 11.9 months. Sensitivity to bortezomib did not affect the PFS, whereas lenalidomide-refractory patients had significantly lower PFS than lenalidomide-sensitive patients, who were comparable to TOURMALINE-MM1 study. The patients with IgG type had significantly better PFS and OS than those with non-IgG type.

CONCLUSION

This study presents the largest real-world data of patients treated with IRd in Asia. However, in real clinical practice, the patient background is different from the TOURMALINE-MM1 study, and IRd showed poor efficacy, especially in the non-IgG type and lenalidomide-refractory patients with RRMM.

Treatment of relapsed multiple myeloma: Evidence-based recommendations

The practice of choosing the next best therapy for patients with relapsed and/or refractory multiple myeloma (RRMM) is becoming increasingly complex. There is no clear consensus regarding the best treatment sequence for RRMM. With the approval of novel proteasome inhibitors (ixazomib and carfilzomib), immunomodulatory agents (pomalidomide), monoclonal antibodies (daratumumab and elotuzumab), and other targeted therapies, multiple combination regimens utilizing these agents are being studied with the goal of enhancing disease control, prolonging progression-free survival, and improving overall survival. We, herein, describe a review of FDA-approved regimens for RRMM patients and offer a paradigm in selecting subsequent treatment regimens, focusing on patient specific morbidity, treatment toxicity, and disease-specific characteristics.

Pharmacodynamics and pharmacokinetics of proteasome inhibitors for the treatment of multiple myeloma

Introduction: Multiple myeloma (MM) is the second most commonly diagnosed hematologic malignancy and has an increasing incidence and prevalence globally, and proteasome inhibitors (PIs) form the backbone of some of our most effective regimens for all phases of this disease in fit and frail patients. Areas covered: Strong understanding of the proteasome complex is increasingly important as the rapid development of new PIs and innovative myeloma therapies complicate the use of old and new combination regimens. We focus herein on the pharmacodynamics and pharmacokinetics of the approved PIs and others in development, including their safety and efficacy in corresponding clinical studies. Expert opinion: Advancements such as the first oral PI, ixazomib, with a more convenient route of administration and improved toxicity profile led to an improved quality of life, patient compliance, and all-oral combination regimens which are efficacious for long-term management of standard and high-risk MM. Novel pan-PIs, such as marizomib, hold the promise of superior clinical activity due to irreversible targeting of all multicatalytic proteinase complex subunits. Development of clinically validated biomarkers of PI sensitivity/resistance is required to inform utilization of the most optimal and effective, rationally targeted PI treatments for all MM patients.

Clinical Pharmacology of Ixazomib: The First Oral Proteasome Inhibitor

Ixazomib, the first oral proteasome inhibitor, is approved in combination with lenalidomide and dexamethasone for the treatment of patients with multiple myeloma (MM) who have received at least one prior therapy. Ixazomib is a selective, potent, and reversible inhibitor of the 20S proteasome, and preferentially binds to and inhibits the β5 chymotrypsin-like proteolytic site. Ixazomib absorption is rapid, with a median time to reach maximum plasma concentration of approximately 1 h post-dose. Ixazomib pharmacokinetics (PK) are adequately described by a three-compartment model (terminal half-life of 9.5 days) with first-order linear absorption (oral bioavailability of 58%). Plasma exposures of ixazomib increase in a dose-proportional manner. A high-fat meal decreases both the rate and extent of ixazomib absorption, supporting administration on an empty stomach. Population PK analyses demonstrated that no dose adjustment is required based on age, body size/weight, race, sex, mild-to-moderate renal impairment, or mild hepatic impairment. Results from dedicated studies indicate that a reduced starting dose (from 4 to 3 mg) is appropriate for patients with severe renal impairment, end-stage renal disease requiring dialysis, or moderate-to-severe hepatic impairment. Non-cytochrome P450 (CYP)-mediated metabolism appears to be the major clearance mechanism for ixazomib. Drug-drug interaction studies have shown no meaningful effects of strong inhibitors of CYP3A on ixazomib PK; however, the strong inducer rifampin caused a clinically relevant reduction in ixazomib exposure, supporting the recommendation to avoid concomitant administration of ixazomib with strong CYP3A inducers. Exposure-response analyses of data from the phase III TOURMALINE-MM1 registrational study demonstrate a favorable benefit-risk profile for the approved dose and regimen of weekly ixazomib 4 mg on days 1, 8, and 15 of each 28-day cycle.

Model-Informed Drug Development for Ixazomib, an Oral Proteasome Inhibitor

Model-informed drug development (MIDD) was central to the development of the oral proteasome inhibitor ixazomib, facilitating internal decisions (switch from body surface area (BSA)-based to fixed dosing, inclusive phase III trials, portfolio prioritization of ixazomib-based combinations, phase III dose for maintenance treatment), regulatory review (model-informed QT analysis, benefit-risk of 4 mg dose), and product labeling (absolute bioavailability and intrinsic/extrinsic factors). This review discusses the impact of MIDD in enabling patient-centric therapeutic optimization during the development of ixazomib.

Proteasome inhibitors for multiple myeloma

Therapeutic strategies for multiple myeloma have dramatically changed in the last two decades, especially after the introduction of proteasome inhibitors. The first-in-class proteasome inhibitor, bortezomib, was approved by the US Food and Drug Administration in 2003. Since then, it has been a backbone therapy for not only relapsed or refractory myeloma patients but also newly diagnosed multiple myeloma patients. Second-generation proteasome inhibitors, such as carfilzomib and ixazomib, have been approved, and three proteasome inhibitors were incorporated into several regimens with other cytotoxic agents, such as alkylating agents, immunomodulatory drugs and monoclonal antibodies. Because each proteasome inhibitor shows different properties with respect to adverse events, understanding and managing each adverse event of proteasome inhibitors are necessary for the continuation of therapy with minimal interruption of treatment. This review summarizes the recent advances in proteasome inhibitors used in the treatment of multiple myeloma.

Ixazomib in the management of relapsed multiple myeloma

The development of proteasome inhibitors contributed to the dramatic life expectancy improvement observed in myeloma patients over the past decades. Ixazomib is a boron-containing selective and reversible proteasome inhibitor that demonstrated antimyeloma activity with excellent safety profile. Ixazomib is the first orally available proteasome inhibitor approved in combination with lenalidomide and dexamethasone for the treatment of myeloma patients who received at least one prior therapy. The present review addresses the current knowledge regarding the clinical use of ixazomib in relapsed myeloma patients.

Dose and Schedule Selection of the Oral Proteasome Inhibitor Ixazomib in Relapsed/Refractory Multiple Myeloma: Clinical and Model-Based Analyses

Background

The oral proteasome inhibitor ixazomib has been approved by regulatory authorities around the world, including in the United States and the European Union, for the treatment of patients with multiple myeloma (MM) who have received at least one prior therapy, based on the pivotal phase III TOURMALINE-MM1 study.

Objective

The objective of this study was to quantitatively characterize the benefit–risk profile of ixazomib in relapsed/refractory MM in support of the approved dose and schedule.

Methods

We report early-phase study data and exposure–response analyses of TOURMALINE-MM1 data that support the selection of the recommended ixazomib dose and schedule.

Results

Single-agent ixazomib studies showed a favorable efficacy/safety profile with weekly versus twice-weekly dosing; a phase I/II study of ixazomib in combination with lenalidomide and dexamethasone (IRd) identified a weekly ixazomib dose that offered an acceptable efficacy/safety profile. In IRd exposure–response analyses from TOURMALINE-MM1, ixazomib systemic exposure was not a significant predictor of progression-free survival or probability of response. Significant associations were observed between ixazomib exposure and the probability of grade ≥3 anemia and thrombocytopenia, and grade ≥2 diarrhea, fatigue, nausea, peripheral neuropathy, and rash. Additionally, higher ixazomib exposure was associated with lower lenalidomide relative dose intensity.

Conclusions

These analyses support a favorable benefit–risk profile for weekly ixazomib 4.0 mg on days 1, 8, and 15 of 28-day cycles, which was selected for the phase III TOURMALINE registration program.

Trial Registration Numbers

ClinicalTrials.gov NCT00932698, NCT00963820, NCT01217957, NCT01564537

Electronic supplementary material

The online version of this article (doi:10.1007/s11523-017-0524-3) contains supplementary material, which is available to authorized users.

Population Pharmacokinetic Analysis of Ixazomib, an Oral Proteasome Inhibitor, Including Data from the Phase III TOURMALINE-MM1 Study to Inform Labelling

Ixazomib is an oral proteasome inhibitor, approved in USA, Canada, Australia and Europe in combination with lenalidomide and dexamethasone, for the treatment of patients with multiple myeloma who have received at least one prior therapy. We report a population pharmacokinetic model-based analysis for ixazomib that was pivotal in describing the clinical pharmacokinetics of ixazomib, to inform product labelling. Plasma concentration–time data were collected from 755 patients who received oral or intravenous ixazomib in once- or twice-weekly schedules in ten trials, including the global phase III TOURMALINE-MM1 study. Data were analysed using nonlinear mixed-effects modelling (NONMEM software version 7.2, ICON Development Solutions, Hanover, MD, USA). Ixazomib plasma concentrations from intravenous and oral studies were described by a three-compartment model with linear distribution and elimination kinetics, including first-order linear absorption with a lag time describing the oral dose data. Body surface area on the volume of the second peripheral compartment was the only covariate included in the final model. None of the additional covariates tested including body surface area (1.2–2.7 m²), sex, age (23–91 years), race, mild/moderate renal impairment and mild hepatic impairment were found to impact systemic clearance, suggesting that no dose adjustment is required based on these covariates. The geometric mean terminal disposition phase half-life was 9.5 days, steady-state volume of distribution was 543 L and systemic clearance was 1.86 L/h. The absolute bioavailability of an oral dose was estimated to be 58%.

Ixazomib: A Review in Relapsed and/or Refractory Multiple Myeloma

The oral proteasome inhibitor ixazomib (Ninlaro^®) is approved in the USA, EU and Japan in combination with lenalidomide and dexamethasone, for the treatment of patients with multiple myeloma (MM) who have received at least one prior therapy. In adults with relapsed and/or refractory MM who had received one to three prior therapies, progression-free survival (PFS) was significantly prolonged in patients who received the ixazomib- versus placebo-based triple therapy in the pivotal, global TOURMALINE-MM1 trial and its regional expansion (China continuation study). A significantly longer time to progression and favourable hazard ratios for PFS were observed across all prespecified subgroups, including patients with high cytogenetic risk. Overall response was achieved in a significantly higher proportion of patients receiving ixazomib- than placebo-based treatment. Ixazomib had a manageable tolerability profile in patients with MM. Ixazomib is the first orally-administered proteasome inhibitor approved for patients with MM, and in combination with lenalidomide and dexamethasone represents an important new option for use in patients with relapsed and/or refractory MM who have previously received at least one prior therapy.

The treatment of paraprotein-related kidney disease

PURPOSE OF REVIEW

Myeloma kidney and amyloid light-chain (AL) amyloidosis remain the principal kidney complications of paraproteins. In this review, we update readers to many of the recent advances which have occurred in the care and outcomes for patients with these presentations.

RECENT FINDINGS

Myeloma kidney has historically caused a severe acute kidney injury with very poor outcomes. The combination of new diagnostic techniques, enabling a rapid diagnosis and novel chemotherapy agents has transformed these poor outcomes for the better. Two multicentre randomized controlled trials have recently evaluated if the removal of free light chains by high cut-off haemodialysis improves renal outcomes beyond effective chemotherapy alone. Although we await the full articles of these studies to be published, abstracts suggested the studies will have contradictory primary results. In the field of AL amyloidosis, there are now novel criteria for the risk stratification of kidney outcomes which can be used in combination with markers of early kidney response to provide clinicians with powerful tools to guide patient discussions.

SUMMARY

Across both AL amyloidosis and myeloma kidney patient outcomes continue to improve. Principally this improvement has been driven by the continuing development of novel chemotherapy agents in this field.

Proteasome inhibitor-induced gastrointestinal toxicity

PURPOSE OF REVIEW

Gastrointestinal toxicities are commonly reported following treatment with proteasome inhibitors. The first-generation proteasome inhibitor, bortezomib, induces significant gastrointestinal side effects including nausea, vomiting, diarrhoea, and constipation, occurring in up to 84% of patients. Despite the development of safer proteasome inhibitors, such as carfilzomib, gastrointestinal toxicities remain some of the most common side effects. This review aims to summarize the previous literature on proteasome inhibitor-induced gastrointestinal toxicities, report on recent updates in the field, and investigate possible mechanisms of this toxicity.

RECENT FINDINGS

Updates in the literature have included a direct comparison of the safety of approved proteasome inhibitors, bortezomib and carfilzomib, reporting less neurotoxicity and similar gastrointestinal toxicity, from carfilzomib when compared with bortezomib. Many recent studies have investigated the safety of orally bioavailable proteasome inhibitors, such as ixazomib and oprozomib. However, little progress has been made in understanding the possible mechanisms of proteasome inhibitor-induced gastrointestinal toxicities.

SUMMARY

Although recent studies have continued to report gastrointestinal toxicities resulting from proteasome inhibitor treatment, particularly when combined with other agents or when administered orally, the mechanisms of proteasome inhibitor-induced gut toxicity remain largely unexplored. Further studies are needed to investigate the pathophysiology of this toxicity to improve the safety of existing and novel proteasome inhibitors.

Acute Pancreatitis Associated with Ixazomib in a Multiple Myeloma Patient

BACKGROUND

Acute pancreatitis is an uncommon complication of anti-myeloma agents. Ixazomib is a first-in-class oral proteasome inhibitor to receive regulatory approval for the treatment of multiple myeloma. This case report describes the first case of ixazomib-associated pancreatitis.

CASE PRESENTATION

An 80-year-old female with relapsed multiple myeloma presented with severe diarrhea, nausea, vomiting, abdominal pain, and acute renal failure 3 weeks after starting ixazomib and dexamethasone for disease progression. An extensive workup revealed acute pancreatitis without a definitive cause. Her condition improved with supportive measures and the discontinutation of ixazomib. The latter was suspected as the probable etiology of the patient's acute pancreatitis, given no clear alternative causes and the temporal relationship between initiating ixazomib and the development of her symptoms.

CONCLUSIONS

Practitioners should include acute pancreatitis as part of their differential diagnosis in patients on ixazomib treatment who present with gastrointestinal symptoms.

Clinical pharmacokinetics of oral drugs in the treatment of multiple myeloma

Treatment of myeloma is a long-term treatment mainly based on all-oral combinations of drugs. Because oral drugs have a more complex pharmacokinetics compared with IV treatments, an appropriate knowledge of the factors that may alter their systemic exposure is of particular clinical relevance. Both drug-drug interactions, food-effect, and dose-adaptation in renal and hepatic impairment may influence the systemic drug levels with a potential impact on drug efficacy or safety. Moreover, a better control of drug exposure may improve the side effect profiles of these treatments with a favourable impact on patient compliance. Furthermore, as long-term treatments, these drugs may also alter the systemic exposure of coadministered medications in these rather old patients. The aim of this review was to identify the factors modifying the systemic exposure of oral drugs used in myeloma by focusing on the pharmacokinetic drug-drug interactions and the effects of renal and hepatic impairment and of food impact.

A phase I study to assess the mass balance, excretion, and pharmacokinetics of [14C]-ixazomib, an oral proteasome inhibitor, in patients with advanced solid tumors

This two-part, phase I study evaluated the mass balance, excretion, pharmacokinetics (PK), and safety of ixazomib in patients with advanced solid tumors. In Part A of the study, patients received a single 4.1 mg oral solution dose of [¹⁴C]-ixazomib containing ~500 nCi total radioactivity (TRA), followed by non-radiolabeled ixazomib (4 mg capsule) on days 14 and 21 of the 35-day PK cycle. Patients were confined to the clinic for the first 168 h post dose and returned for 24 h overnight clinic visits on days 14, 21, 28, and 35. Blood, urine, and fecal samples were collected during Part A to assess the mass balance (by accelerator mass spectrometry), excretion, and PK of ixazomib. During Part B of the study, patients received non-radiolabeled ixazomib (4 mg capsules) on days 1, 8, and 15 of 28-day cycles. After oral administration, ixazomib was rapidly absorbed with a median plasma T_max of 0.5 h and represented 70% of total drug-related material in plasma. The mean total recovery of administered TRA was 83.9%; 62.1% in urine and 21.8% in feces. Only 3.23% of the administered dose was recovered in urine as unchanged drug up to 168 h post dose, suggesting that most of the TRA in urine was attributable to metabolites. All patients experienced a treatment-emergent adverse event, which most commonly involved the gastrointestinal system. These findings suggest that ixazomib is extensively metabolized, with urine representing the predominant route of excretion of drug-related material.Trial ID: ClinicalTrials.gov # NCT01953783.

New developments in the management of relapsed/refractory multiple myeloma - the role of ixazomib

Ixazomib is the first oral proteasome inhibitor to be approved, in combination with lenalidomide and dexamethasone, for the treatment of patients with multiple myeloma who have received at least one prior therapy. Approval was on the basis of results from the phase 3, double-blind, placebo-controlled TOURMALINE-MM1 study, which demonstrated a 35% improvement in progression-free survival with the all-oral combination of ixazomib plus lenalidomide-dexamethasone versus lenalidomide-dexamethasone alone (median: 20.6 vs 14.7 months; hazard ratio: 0.74, p=0.012; median follow-up 14.7 months). The addition of ixazomib to the lenalidomide-dexamethasone regimen was associated with limited additional toxicity and had no adverse impact on patient-reported quality of life. Common grade ≥3 adverse events with ixazomib include gastrointestinal adverse events, rash, and thrombocytopenia. Here, we review the efficacy, safety, pharmacokinetics, and patient-reported quality of life data seen with ixazomib, and discuss the role of this oral agent in the treatment of patients with relapsed/refractory multiple myeloma, including in patients with high-risk cytogenetic abnormalities and those with multiple prior therapies.

Effects of Strong CYP3A Inhibition and Induction on the Pharmacokinetics of Ixazomib, an Oral Proteasome Inhibitor: Results of Drug-Drug Interaction Studies in Patients With Advanced Solid Tumors or Lymphoma and a Physiologically Based Pharmacokinetic Analysis

At clinically relevant ixazomib concentrations, in vitro studies demonstrated that no specific cytochrome P450 (CYP) enzyme predominantly contributes to ixazomib metabolism. However, at higher than clinical concentrations, ixazomib was metabolized by multiple CYP isoforms, with the estimated relative contribution being highest for CYP3A at 42%. This multiarm phase 1 study (Clinicaltrials.gov identifier: NCT01454076) investigated the effect of the strong CYP3A inhibitors ketoconazole and clarithromycin and the strong CYP3A inducer rifampin on the pharmacokinetics of ixazomib. Eighty-eight patients were enrolled across the 3 drug-drug interaction studies; the ixazomib toxicity profile was consistent with previous studies. Ketoconazole and clarithromycin had no clinically meaningful effects on the pharmacokinetics of ixazomib. The geometric least-squares mean area under the plasma concentration-time curve from 0 to 264 hours postdose ratio (90%CI) with vs without ketoconazole coadministration was 1.09 (0.91-1.31) and was 1.11 (0.86-1.43) with vs without clarithromycin coadministration. Reduced plasma exposures of ixazomib were observed following coadministration with rifampin. Ixazomib area under the plasma concentration-time curve from time 0 to the time of the last quantifiable concentration was reduced by 74% (geometric least-squares mean ratio of 0.26 [90%CI 0.18-0.37]), and maximum observed plasma concentration was reduced by 54% (geometric least-squares mean ratio of 0.46 [90%CI 0.29-0.73]) in the presence of rifampin. The clinical drug-drug interaction study results were reconciled well by a physiologically based pharmacokinetic model that incorporated a minor contribution of CYP3A to overall ixazomib clearance and quantitatively considered the strength of induction of CYP3A and intestinal P-glycoprotein by rifampin. On the basis of these study results, the ixazomib prescribing information recommends that patients should avoid concomitant administration of strong CYP3A inducers with ixazomib.

A Phase 1 Study to Assess the Relative Bioavailability of Two Capsule Formulations of Ixazomib, an Oral Proteasome Inhibitor, in Patients With Advanced Solid Tumors or Lymphoma

The oral proteasome inhibitor ixazomib is approved in multiple countries in combination with lenalidomide and dexamethasone for the treatment of patients with multiple myeloma who have received at least 1 prior therapy. Two oral capsule formulations of ixazomib have been used during clinical development. This randomized, 2-period, 2-sequence crossover study (Clinicaltrials.gov identifier NCT01454076) assessed the relative bioavailability of capsule B in reference to capsule A in adult patients with advanced solid tumors or lymphoma. The study was conducted in 2 parts. In cycle 1 (pharmacokinetic cycle), patients received a 4-mg dose of ixazomib as capsule A or capsule B on day 1, followed by a 4-mg dose of the alternate capsule formulation on day 15. Pharmacokinetic samples were collected over 216 hours postdose. After the pharmacokinetic cycle, patients could continue in the study and receive ixazomib (capsule B only) on days 1, 8, and 15 of each 28-day cycle. Twenty patients were enrolled; of these, 14 were included in the pharmacokinetic-evaluable population. Systemic exposures of ixazomib were similar after administration of capsule A or capsule B. The geometric least-squares mean ratios (capsule B versus capsule A) were 1.16 for C_max (90% confidence interval [CI], 0.84-1.61) and 1.04 for AUC_0-216 (90%CI, 0.91-1.18). The most frequently reported grade 3 drug-related adverse events were fatigue (15%) and nausea (10%); there were no grade 4 drug-related adverse events. These results support the combined analysis of data from studies that used either formulation of ixazomib during development.

Management of adverse events associated with ixazomib plus lenalidomide/dexamethasone in relapsed/refractory multiple myeloma

The oral proteasome inhibitor ixazomib is approved in the United States, European Union and other countries, in combination with oral lenalidomide and dexamethasone (Rd), for the treatment of patients with multiple myeloma who have received at least one prior therapy. Approval was based on the global, randomised, double-blind, placebo-controlled Phase III TOURMALINE-MM1 study of ixazomib-Rd (IRd) versus placebo-Rd in patients with relapsed/refractory multiple myeloma. IRd resulted in a significant improvement in progression-free survival versus placebo-Rd (median: 20·6 vs. 14·7 months; hazard ratio 0·74). Common toxicities observed more commonly with IRd versus placebo-Rd were thrombocytopenia, nausea, vomiting, diarrhoea, constipation, rash, peripheral neuropathy, peripheral oedema and back pain; these were generally grade 1/2 in severity except for thrombocytopenia (19% vs. 9% grade 3/4), which appeared manageable and reversible, with no differences between arms in significant bleeding or dose discontinuations. No cumulative toxicities were observed, indicating the potential feasibility of long-term IRd treatment. Safety data from TOURMALINE-MM1 are reviewed and guidance for managing clinically relevant adverse events associated with IRd is provided. Most toxicities were manageable with supportive care and dose delays or reductions as needed. Clinicians should be aware of and understand these potential side effects to optimise and prolong patient benefit.

Safety of ixazomib for the treatment of multiple myeloma

INTRODUCTION

Despite a major positive impact of proteasome inhibitors (PI), such as bortezomib and carfilzomib, on the survival of patients with multiple myeloma (MM) over the last few years, their use in clinical practice is limited by the development of drug resistance, significant side-effects or constraining administration schedules. Ixazomib is the first, and for now the only, oral PI, which was approved by the US Food and Drug Administration in 2015 and by the European Medicines Agency in 2016. Areas covered: In this review, we provide an overview of the preclinical and early-phase studies of ixazomib used as single-agent and in combination. Furthermore, we discuss the results of a recently published pivotal trial, which evaluated the safety profile and clinical benefit of the combination of ixazomib, lenalidomide and dexamethasone versus lenalidomide and dexamethasone alone in 722 patients with relapsed/refractory MM. Expert opinion: Ixazomib combines the comfort of oral administration, substantial clinical efficacy and a good safety profile with manageable side-effects, which mainly comprise low-grade hematological, digestive or cutaneous events, and the agent will therefore play an active part in long-term treatment strategies, both as single agent and as part of combination regimens. Ongoing phase III trials are currently defining its place in first-line, maintenance and relapse settings.

The proteasome - victim or culprit in autoimmunity

The ubiquitin proteasome system is closely connected to apoptosis, autophagy, signaling of inflammatory cytokines and generation of ligands for MHC class I antigen presentation. Proteasome function in the innate immune response becomes particularly evident in patients with proteasome-associated autoinflammatory syndromes (PRAAS), where disease causing mutations result in reduced proteasome activity. PRAAS can be classified as a novel type of interferonopathy, however the molecular mechanism and signaling pathways leading from impaired proteasome capacity, the accumulation of damaged proteins, and the induction of type I IFN-genes remain to be determined. In contrast, several studies have confirmed an up-regulation of inducible subunits of the proteasome in systemic autoimmune diseases. Since proteasome inhibition was shown to be efficacious in several in-vitro studies and animal models of autoimmune diseases, it is justified to investigate the application of proteasome inhibitors in human disease. In this context, a number of available proteasome inhibitors has been characterized as potent immune-suppressants. The mode of action of proteasome inhibition interferes with the quality control of the huge amounts of synthetized antibodies causing an unfolded protein response. Further effects of proteasome inhibition includes inhibition of NFκB activation as well as direct activation of intrinsic and extrinsic pathways of apoptosis. The preliminary clinical work on proteasome inhibition in autoimmune diseases comprises only few studies in small cohorts with promising effects, which needs to be confirmed in controlled clinical trials.