Strategies to address drug interaction potential for antibody-drug conjugates in clinical development

Anti-Lymphocyte Antigen 6 Complex, Locus E-Seco-Cyclopropabenzindol-4-One-Dimer Antibody-Drug Conjugate That Forms Adduct with α1-Microglobulin Demonstrates Slower Systemic Antibody Clearance and Reduced Tumor Distribution in Animals

Anti-Ly6E-seco-cyclopropabenzindol-4-one dimer antibody-drug conjugate (ADC) has been reported to form an adduct with α1-microglobulin (A1M) in animal plasma, but with unknown impact on ADC PK and tissue distribution. In this study, we compared the PK and tissue distribution of anti-Ly6E ADC with unconjugated anti-Ly6E mAb in rodents and monkeys. For PK studies, animals received an intravenous administration of anti-Ly6E ADC or unconjugated anti-Ly6E mAb. Plasma samples were analyzed for total antibody (Tab) levels and A1M adduct formation. PK parameters were generated from dose-normalized plasma concentrations. Tissue distribution was determined in tumor-bearing mice after a single intravenous dosing of radiolabeled ADC or mAb. Tissue radioactivity levels were analyzed using a gamma counter. The impact of A1M adduct formation on target cell binding was assessed in an in vitro cell binding assay. The results show that ADC Tab clearance was slower than that of mAb in mice and rats but faster than mAb in monkeys. Correspondingly, the formation of A1M adduct appeared to be faster and higher in mice, followed by rats, and slowest in monkeys. Although ADC tended to show an overall lower distribution to normal tissues, it had a strikingly reduced distribution to tumors compared with mAb, likely due to A1M adduct formation interfering with target binding, as demonstrated by the in vitro cell binding assay. Together, these data 1) demonstrate that anti-Ly6E ADC that forms A1M adduct had slower systemic clearance with strikingly reduced tumor distribution and 2) highlight the importance of selecting an appropriate linker-drug for successful ADC development. SIGNIFICANCE STATEMENT: Anti-lymphocyte antigen 6 complex, locus E, ADC with seco-cyclopropabenzindol-4-one-dimer payload formed adduct with A1M, which led to a decrease in systemic clearance but also attenuated tumor distribution. These findings demonstrate the importance of selecting an appropriate linker-drug for ADC development and also highlight the value of a mechanistic understanding of ADC biotransformation, which could provide insight into ADC molecule design, optimization, and selection.

Polatuzumab vedotin, an anti-CD79b antibody-drug conjugate for the treatment of relapsed/refractory diffuse large B-cell lymphoma

Refractory/relapsed diffuse large B-cell lymphoma remains a major unmet medical need with poor outcome, especially for patients considered ineligible for stem cell transplant. Polatuzumab vedotin (PV) is a first-in-class anti-CD79b antibody-drug conjugate that contains the microtubule inhibitor monomethyl auristatin E. The development of PV is currently very active. This drug was US FDA approved in 2019 in combination with bendamustine and rituximab for the treatment of refractory/relapsed diffuse large B-cell lymphoma in third line and more, after demonstrating relevant efficacy and acceptable safety in a pivotal randomized Phase II trial. This review summarizes the features of this new drug with the primary focus on the clinical work supporting efficacy, relevance and tolerability of PV.

Pharmacokinetics of polatuzumab vedotin in combination with R/G-CHP in patients with B-cell non-Hodgkin lymphoma

Purpose

The phase Ib/II open-label study (NCT01992653) evaluated the antibody-drug conjugate polatuzumab vedotin (pola) plus rituximab/obinutuzumab, cyclophosphamide, doxorubicin, and prednisone (R/G-CHP) as first-line therapy for B-cell non-Hodgkin lymphoma (B-NHL). We report the pharmacokinetics (PK) and drug–drug interaction (DDI) for pola.

Methods

Six or eight cycles of pola 1.0–1.8 mg/kg were administered intravenously every 3 weeks (q3w) with R/G-CHP. Exposures of pola [including antibody-conjugated monomethyl auristatin E (acMMAE) and unconjugated MMAE] and R/G-CHP were assessed by non-compartmental analysis and/or descriptive statistics with cross-cycle comparisons to cycle 1 and/or after multiple cycles. Pola was evaluated as a potential victim and perpetrator of a PK drug–drug interaction with R/G-CHP. Population PK (popPK) analysis assessed the impact of prior treatment status (naïve vs. relapsed/refractory) on pola PK.

Results

Pola PK was similar between treatment arms and independent of line of therapy. Pola PK was dose proportional from 1.0 to 1.8 mg/kg with R/G-CHP. Geometric mean volume of distribution and clearance of acMMAE ranged from 57.3 to 95.6 mL/kg and 12.7 to 18.2 mL/kg/day, respectively. acMMAE exhibited multi-exponential decay (elimination half-life ~ 1 week). Unconjugated MMAE exhibited formation rate-limited kinetics. Exposures of pola with R/G-CHP were similar to those in the absence of CHP; exposures of R/G-CHP in the presence of pola were comparable to those in the absence of pola.

Conclusions

Pola PK was well characterized with no clinically meaningful DDIs with R/G-CHP. Findings are consistent with previous studies of pola + R/G, and support pola + R/G-CHP use in previously untreated diffuse large B-cell lymphoma.

Electronic supplementary material

The online version of this article (10.1007/s00280-020-04054-8) contains supplementary material, which is available to authorized users.

Antibody-Drug Conjugates: Pharmacokinetic/Pharmacodynamic Modeling, Preclinical Characterization, Clinical Studies, and Lessons Learned

Antibody-drug conjugates are an emerging class of biopharmaceuticals changing the landscape of targeted chemotherapy. These conjugates combine the target specificity of monoclonal antibodies with the anti-cancer activity of small-molecule therapeutics. Several antibody-drug conjugates have received approval for the treatment of various types of cancer including gemtuzumab ozogamicin (Mylotarg^®), brentuximab vedotin (Adcetris^®), trastuzumab emtansine (Kadcyla^®), and inotuzumab ozogamicin, which recently received approval (Besponsa^®). In addition to these approved therapies, there are many antibody-drug conjugates in the drug development pipeline and in clinical trials, although these fall outside the scope of this article. Understanding the pharmacokinetics and pharmacodynamics of antibody-drug conjugates and the development of pharmacokinetic/pharmacodynamic models is indispensable, albeit challenging as there are many parameters to incorporate including the disposition of the intact antibody-drug conjugate complex, the antibody, and the drug agents following their dissociation in the body. In this review, we discuss how antibody-drug conjugates progressed over time, the challenges in their development, and how our understanding of their pharmacokinetics/pharmacodynamics led to greater strides towards successful targeted therapy programs.

Pharmacokinetics of trastuzumab emtansine (T-DM1) as a single agent or in combination with pertuzumab in HER2-positive breast cancer patients with recurrent or locally advanced metastatic breast cancer

PURPOSE

The phase III MARIANNE study investigated single-agent trastuzumab emtansine (T-DM1) and combination T-DM1 plus pertuzumab as the first-line treatment for human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC). Pharmacokinetic properties of T-DM1 and pertuzumab in these patients and the potential for drug-drug interactions (DDIs) were assessed.

METHODS

Pharmacokinetic samples of T-DM1-related analytes (T-DM1 conjugate, total trastuzumab, DM1) and pertuzumab were analyzed. Observed pharmacokinetic data were summarized for all analytes. Historical population pharmacokinetic models for T-DM1 conjugate and pertuzumab in HER2-positive MBC were used to derive empirical Bayes estimates of pharmacokinetic parameters.

RESULTS

In MARIANNE (N = 375), mean ± standard deviation population pharmacokinetic model-predicted Cycle 1 C_max for T-DM1 conjugate was 74.4 ± 10.1 µg/mL, Cycle 1 C_trough was 1.34 ± 0.802 µg/mL, and area under the concentration-time curve from time zero to infinity after first dose (AUC_inf) was 338 ± 69.5 µg*day/mL. These values were similar to other T-DM1 studies. Pharmacokinetics of T-DM1 conjugate and other analytes (total trastuzumab, DM1) were similar with or without pertuzumab. In the pertuzumab plus T-DM1 arm, mean model-predicted Cycle 1 pertuzumab C_max, C_trough, and AUC_inf were 276 ± 50.0 µg/mL, 64.8 ± 17.9 μg/mL, and 4470 ± 1360 µg*day/mL, respectively. These values were similar to other pertuzumab studies.

CONCLUSIONS

Based on the population pharmacokinetic analysis of T-DM1 conjugate and pertuzumab, pharmacokinetics are similar across different lines of treatment and stages of disease including previously untreated MBC patients, and no DDIs were identified for combined use of T-DM1 and pertuzumab.

Antibody-drug conjugates for cancer therapy: The technological and regulatory challenges of developing drug-biologic hybrids

Antibody-drug conjugates (ADCs) are a new class of therapeutic agents that combine the targeting ability of monoclonal antibodies (mAbs) with small molecule drugs. The combination of a mAb targeting a cancer-specific antigen with a cytotoxin has tremendous promise as a new type of targeted cancer therapy. Two ADCs have been approved and many more are in clinical development, suggesting that this new class of drugs is coming to the forefront. Because of their unique nature as biologic-small drug hybrids, ADCs are challenging to develop, from both the scientific and regulatory perspectives. This review discusses both these aspects in current practice, and surveys the current state of the art of ADC drug development.

Semi-mechanistic Multiple-Analyte Pharmacokinetic Model for an Antibody-Drug-Conjugate in Cynomolgus Monkeys

Purpose

A semi-mechanistic multiple-analyte population pharmacokinetics (PK) model was developed to describe the complex relationship between the different analytes of monomethyl auristatin E (MMAE) containing antibody-drug conjugates (ADCs) and to provide insight regarding the major pathways of conjugate elimination and unconjugated MMAE release in vivo.

Methods

For an anti-CD79b-MMAE ADC the PK of total antibody (Tab), conjugate (evaluated as antibody conjugated MMAE or acMMAE), and unconjugated MMAE were quantified in cynomolgus monkeys for single (0.3, 1, or 3 mg/kg), and multiple doses (3 or 5 mg/kg, every-three-weeks for 4 doses). The PK data of MMAE in cynomolgus monkeys, after intravenous administration of MMAE at single doses (0.03 or 0.063 mg/kg), was included in the analysis. A semi-mechanistic model was developed and parameter estimates were obtained by simultaneously fitting the model to all PK data using a hybrid ITS-MCPEM method.

Results

The final model well described the observed Tab, acMMAE and unconjugated MMAE concentration-time profiles. Analysis suggested that conjugate is lost via both proteolytic degradation and deconjugation, while unconjugated MMAE in systemic circulation appears to be mainly released via proteolytic degradation of the conjugate.

Conclusions

Our model improves the understanding of ADC catabolism, which may provide useful insights when designing future ADCs.

Electronic supplementary material

The online version of this article (doi:10.1007/s11095-014-1585-y) contains supplementary material, which is available to authorized users.

Antibody-drug conjugates: current status and future directions

Antibody-drug conjugates (ADCs) aim to take advantage of the specificity of monoclonal antibodies (mAbs) to deliver potent cytotoxic drugs selectively to antigen-expressing tumor cells. Despite the simple concept, various parameters must be considered when designing optimal ADCs, such as selection of the appropriate antigen target and conjugation method. Each component of the ADC (the antibody, linker and drug) must also be optimized to fully realize the goal of a targeted therapy with improved efficacy and tolerability. Advancements over the past several decades have led to a new generation of ADCs comprising non-immunogenic mAbs, linkers with balanced stability and highly potent cytotoxic agents. Although challenges remain, recent clinical success has generated intense interest in this therapeutic class.