An Integrated Assessment of the Effects of Immunogenicity on the Pharmacokinetics, Safety, and Efficacy of Elotuzumab

Immunotherapy of Multiple Myeloma: Promise and Challenges

Whereas the treatment of MM was dependent solely on alkylating agents and corticosteroids during the prior three decades, the landscape of therapeutic measures to treat the disease began to expand enormously early in the current century. The introduction of new classes of small-molecule drugs, such as proteasome blockers (bortezomib and carfilzomib), immunomodulators (lenalidomide and pomalidomide), nuclear export inhibitors (selinexor), and histone deacetylase blockers (panobinostat), as well as the application of autologous stem cell transplantation (ASCT), resulted in a seismic shift in how the disease is treated. The picture changed dramatically once again starting with the 2015 FDA approval of two monoclonal antibodies (mAbs) - the anti-CD38 daratumumab and the anti-SLAMF7 elotuzumab. Daratumumab, in particular, has had a great impact on MM therapy and today is often included in various regimens to treat the disease, both in newly diagnosed cases and in the relapse/refractory setting. Recently, other immunotherapies have been added to the arsenal of drugs available to fight this malignancy. These include isatuximab (also anti-CD38) and, in the past year, the antibody-drug conjugate (ADC) belantamab mafodotin and the chimeric antigen receptor (CAR) T-cell product idecabtagene vicleucel (ide-cel). While the accumulated benefits of these newer agents have resulted in a doubling of the disease's five-year survival rate to more than 5 years and improved quality of life, the disease remains incurable. Almost without exception patients experience relapse and/or become refractory to the drugs used, making the search for innovative therapies all the more essential. This review covers the current scope of anti-myeloma immunotherapeutic agents, both those in clinical use and on the horizon, including naked mAbs, ADCs, bi- and multi-targeted mAbs, and CAR T-cells. Emphasis is placed on the benefits of each along with the challenges that need to be overcome if MM is to be considered curable in the future.

Elotuzumab in the treatment of relapsed and refractory multiple myeloma

Multiple myeloma (MM) is still considered an incurable disease. However, drugs with different mechanisms of action that can improve the efficiency of treatment offer hope. Still, there are concerns about an unacceptable increase in toxicity with such regimens. The results of recently published clinical studies of elotuzumab in combination with lenalidomide/dexamethasone or pomalidomide/dexamethasone confirm previous hopes to improve the effect of that treatment. Humanized monoclonal antibodies aimed at SLAMF7 stimulate natural killer cells to fight against MM cells. Elotuzumab used in combination with lenalidomide/dexamethasone or with pomalidomide/dexamethasone is approved by the US FDA to treat patients with relapsed and/or refractory MM. The article is a summary of the recent knowledge about the possibility of using elotuzumab in the treatment of relapsed and/or refractory MM and shows its potential uses in the future.

The Molecular Mechanisms That Underlie the Immune Biology of Anti-drug Antibody Formation Following Treatment With Monoclonal Antibodies

Monoclonal antibodies (mAbs) are a crucial asset for human health and modern medicine, however, the repeated administration of mAbs can be highly immunogenic. Drug immunogenicity manifests in the generation of anti-drug antibodies (ADAs), and some mAbs show immunogenicity in up to 70% of patients. ADAs can alter a drug's pharmacokinetic and pharmacodynamic properties, reducing drug efficacy. In more severe cases, ADAs can neutralize the drug's therapeutic effects or cause severe adverse events to the patient. While some contributing factors to ADA formation are known, the molecular mechanisms of how therapeutic mAbs elicit ADAs are not completely clear. Accurate ADA detection is necessary to provide clinicians with sufficient information for patient monitoring and clinical intervention. However, ADA assays present unique challenges because both the analyte and antigen are antibodies, so most assays are cumbersome, costly, time consuming, and lack standardization. This review will discuss aspects related to ADA formation following mAb drug administration. First, we will provide an overview of the prevalence of ADA formation and the available diagnostic tools for their detection. Next, we will review studies that support possible molecular mechanisms causing the formation of ADA. Finally, we will summarize recent approaches used to decrease the propensity of mAbs to induce ADAs.

Model-Based Determination of Elotuzumab Pharmacokinetics in Japanese Patients With Multiple Myeloma Incorporating Time-Varying M Protein

A population pharmacokinetic model was developed to evaluate the effects of Japanese ethnicity, prior line of therapy (0 or ≥1), time-varying M protein, and maintenance dosing regimens (10 mg/kg intravenously every 2 weeks or 20 mg/kg intravenously every 4 weeks beginning in cycle 19) on the pharmacokinetics of elotuzumab in patients with multiple myeloma treated with elotuzumab plus lenalidomide/dexamethasone. Elotuzumab pharmacokinetics were characterized by a 2-compartment model with parallel linear (nonspecific) and Michaelis-Menten elimination from the central compartment and target-mediated elimination from the peripheral compartment. Asian race on nonspecific clearance (CL) and central volume of distribution, prior line of therapy on CL, and maximum target-mediated elimination rate (V_max ) were statistically significant but not considered clinically relevant (magnitude < 20%). Time-varying M protein on V_max was statistically significant, and the magnitude was >20%; however, clinical implications in the setting of combination therapy were not expected. Model-predicted steady-state elotuzumab exposure in cycle 12 were similar in Japanese and non-Japanese patients and in Japanese patients with 0 and ≥1 prior lines of therapy. Elotuzumab 20 mg/kg intravenously every 4 weeks beginning in cycle 19 produced time-averaged concentrations similar to elotuzumab 10 mg/kg intravenously every 2 weeks, although maximum and minimum concentrations after elotuzumab 20 mg/kg intravenous every-4-week dosing were slightly higher and lower, respectively. In conclusion, the current analysis demonstrates that Japanese ethnicity, prior line of therapy, time-varying M protein, and change in elotuzumab dosing regimen in cycle 19 have no clinically meaningful impact on elotuzumab pharmacokinetics and exposure in Japanese patients with multiple myeloma.

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

Intravenous elotuzumab (Empliciti™), a monoclonal antibody targeting the signalling lymphocytic activation molecule F7 (SLAMF7) glycoprotein, is approved for use in combination with lenalidomide and dexamethasone for the treatment of multiple myeloma in previously-treated adult patients. In the pivotal, multinational, phase III ELOQUENT-2 trial in adults with relapsed and/or refractory multiple myeloma, elotuzumab in combination with lenalidomide and dexamethasone significantly prolonged median progression-free survival (PFS) and increased overall response rate (ORR; co-primary endpoints) compared with lenalidomide and dexamethasone alone. The clinical benefit of elotuzumab was maintained over the longer term (≤ 4 years' minimum follow-up); final overall survival data are awaited. Health-related quality of life was not negatively impacted by the addition of elotuzumab. Elotuzumab combination therapy had a generally manageable tolerability profile and the most common adverse events (AEs) of grade ≥ 3 severity were haematological (e.g. lymphocytopenia, anaemia, thrombocytopenia, neutropenia). Elotuzumab plus lenalidomide and dexamethasone extends the treatment options available for the management of relapsed and/or refractory multiple myeloma.

Immunogenicity of antibody-drug conjugates: observations across 8 molecules in 11 clinical trials

Aim: To evaluate the clinical immunogenicity of eight antibody-drug conjugates (ADCs), multi-domain biotherapeutics that could theoretically pose a greater immunogenicity risk than monoclonal antibodies (mAbs) because they contain non-natural structural motifs. Methodology & results: Immunogenicity strategies and assays for these ADCs included those commonly used for conventional biotherapeutics with additional characterization. A tiered approach was adopted for testing Phase I and II clinical study samples with screening, confirmatory assays and additional domain characterization. Antidrug antibody incidences with these ADCs were within those reported for mAb biotherapeutics with no apparent impact on clinical outcomes. Conclusion: These data suggest that the ADC hapten-like structure across these eight ADCs does not appear to increase patient immune responses beyond those generally observed for mAb biotherapeutics.

The Clinical Pharmacology of Elotuzumab

Novel treatment options are needed to improve long-term outcomes for patients with multiple myeloma (MM). In this article, we comprehensively review the clinical pharmacology of elotuzumab, a first-in-class monoclonal anti-SLAMF7 antibody approved in combination with lenalidomide and dexamethasone (ELd) for the treatment of patients with MM and one to three prior therapies. Elotuzumab has a dual mechanism of action to specifically kill myeloma cells: binding SLAMF7 on myeloma cells facilitates natural killer (NK) cell-mediated antibody-dependent cellular cytotoxicity (ADCC), and direct engagement of SLAMF7 on NK cells further enhances NK cell activity. Elotuzumab administration causes transient elevations of selected cytokines (tumor necrosis factor-α, interferon-γ-induced protein-10 and monocyte chemoattractant protein-1). The temporary nature of these elevations (greatest after the first dose, with a trend to return to baseline by day 7) suggests a low likelihood of facilitating clinically meaningful drug-drug interactions. Elotuzumab exposure increases more than proportionally to dose and >80% SLAMF7 receptor occupancy is achieved with the approved elotuzumab 10 mg/kg regimen. Population pharmacokinetic data from 375 patients demonstrated weight-based dosing is appropriate for elotuzumab, and that ethnicity and hepatic/renal function have minimal effects on exposure. Exposure-response analysis of patients treated with ELd demonstrated that increased elotuzumab exposure does not elevate the risk of grade 3+ adverse events (AEs) or AEs leading to discontinuation/death. Elotuzumab antidrug antibodies occurred in 18.5% of patients treated with ELd or elotuzumab plus bortezomib and dexamethasone, but were generally transient and did not affect elotuzumab efficacy or safety. A monotherapy study indicated elotuzumab does not have clinically relevant effects on QT intervals.

Reporting, Visualization, and Modeling of Immunogenicity Data to Assess Its Impact on Pharmacokinetics, Efficacy, and Safety of Monoclonal Antibodies

The rapidly increasing number of therapeutic biologics in development has led to a growing recognition of the need for improvements in immunogenicity assessment. Published data are often inadequate to assess the impact of an antidrug antibody (ADA) on pharmacokinetics, safety, and efficacy, and enable a fully informed decision about patient management in the event of ADA development. The recent introduction of detailed regulatory guidance for industry should help address many past inadequacies in immunogenicity assessment. Nonetheless, careful analysis of gathered data and clear reporting of results are critical to a full understanding of the clinical relevance of ADAs, but have not been widely considered in published literature to date. Here, we review visualization and modeling of immunogenicity data. We present several relatively simple visualization techniques that can provide preliminary information about the kinetics and magnitude of ADA responses, and their impact on pharmacokinetics and clinical endpoints for a given therapeutic protein. We focus on individual sample- and patient-level data, which can be used to build a picture of any trends, thereby guiding analysis of the overall study population. We also discuss methods for modeling ADA data to investigate the impact of immunogenicity on pharmacokinetics, efficacy, and safety.