Safety and pharmacokinetics of polatuzumab vedotin in Japanese patients with relapsed/refractory B-cell non-Hodgkin lymphoma: a phase 1 dose-escalation study

Development of a generalized pharmacokinetic model to characterize clinical pharmacokinetics of monomethyl auristatin E-based antibody-drug conjugates

AIMS

This study aims to develop a generalized pharmacokinetic (PK) model for monomethyl auristatin E (MMAE)-based antibody-drug conjugates (ADCs) that can simultaneously capture the PK of multiple ADC analytes commonly measured in the clinic.

METHODS

A comprehensive literature review was conducted to collect PK data on MMAE-based ADCs from clinical trials. From each study, PK profiles of total antibody, the ADC, conjugated MMAE, and unconjugated MMAE, were extracted. These data were pooled and dose-normalized to evaluate the generalizability of PK across various ADCs and dose levels. Upon confirming PK generalizability, a generalized PK model for MMAE-based ADCs was developed using the entire dataset. Furthermore, exposure metrics ( C max and AUC) reported across the range of doses were combined to establish linear relationships between dose and exposure metrics for MMAE-based ADCs.

RESULTS

A total of 109 PK profiles from 18 distinct MMAE-based ADCs were gathered. The dose-normalized PK profiles supported the generalizability of PK for MMAE-based ADCs. A generalized PK model was developed, which enabled capturing the PK data for 4 ADC analytes across all collected MMAE-based ADCs. A linear relationship between dose and PK exposure metrics was established, enabling the prediction of typical exposure values across different doses for MMAE-based ADCs.

CONCLUSIONS

This study comprehensively analysed clinical PK data from different valine-citrulline (vc)-MMAE-based ADCs. The generalized PK model developed here serves as an important tool for a priori prediction of the PK for multiple ADC analytes in clinical settings and lays the foundation for establishing generalized exposure-response and exposure-toxicity correlations for MMAE-based ADCs.

Clinical pharmacology strategies to accelerate the development of polatuzumab vedotin and summary of key findings

The favorable benefit-risk profile of polatuzumab vedotin, as demonstrated in a pivotal Phase Ib/II randomized study (GO29365; NCT02257567), coupled with the need for effective therapies in relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL), prompted the need to accelerate polatuzumab vedotin development. An integrated, fit-for-purpose clinical pharmacology package was designed to support regulatory approval. To address key clinical pharmacology questions without dedicated clinical pharmacology studies, we leveraged non-clinical and clinical data for polatuzumab vedotin, published clinical data for brentuximab vedotin, a similar antibody-drug conjugate, and physiologically based pharmacokinetic and population pharmacokinetic modeling approaches. We review strategies and model-informed outcomes that contributed to regulatory approval of polatuzumab vedotin plus bendamustine and rituximab in R/R DLBCL. These strategies made polatuzumab vedotin available to patients earlier than previously possible; depending on the strength of available data and the regulatory/competitive environment, they may also prove useful in accelerating the development of other agents.

Polatuzumab vedotin pharmacokinetics in a hemodialysis patient with diffuse large B-cell lymphoma

PURPOSE

Chemotherapy for the hemodialysis (HD) patient is a challenging situation because it requires special considerations including dose modifications and timing of drug administration in relation with HD sessions. Polaltuzumab vedotin (PV), an antibody-drug conjugate in which monomethyl auristatin E (MMAE) is linked to an anti-CD79b monoclonal antibody, is an extremely promising therapeutic for treating diffuse large B cell lymphoma (DLBCL), but the pharmacokinetics are unknown in HD patients.

METHODS

We carried out pharmacokinetic studies of PV when administered at 1.2 mg/kg to a DLBCL patient on HD, and compared the results with that of non-HD patients. PV was administered in conjunction with bendamustine and rituximab.

RESULTS

Serum concentration-time curves of both antibodyconjugated and unconjugated MMAE in the presented HD patient were similar compared to that of non-HD patients. We also demonstrate that elimination of both antibody-conjugated and unconjugated MMAE through HD is limited. PV administration at 1.2 mg/kg to an HD patient was also clinically feasible, and no signs of peripheral neuropathy were observed.

CONCLUSIONS

PV therapy may be a relatively safe treatment method for DLBCL patients on HD.

The forgotten survivor: A comprehensive review on Non-Hodgkin lymphoma survivorship

The number of non-Hodgkin lymphoma (NHL) survivors is increasing. With the advancement of NHL therapies, it is crucial to focus on the challenges these survivors may face. Three main categories are to be considered in NHL survivorship, including quality of life and uncertainty about the future, possible physical health complications (including cardiovascular disease, infertility, and subsequent neoplasms), and the impact of novel NHL treatments and their potential complications. The latter includes CAR T-cell therapy, monoclonal antibodies, checkpoint inhibitors, and hematopoietic stem cell transplantation. In this report, we aim to shed the light on these aspects and to discuss survivorship care plan for NHL.

A phase 2 study of polatuzumab vedotin + bendamustine + rituximab in relapsed/refractory diffuse large B-cell lymphoma

Polatuzumab vedotin (pola) is a CD79b‐targeted antibody‐drug conjugate delivering a potent antimitotic agent (monomethyl auristatin E) to B cells. This was an open‐label, single‐arm study of pola 1.8 mg/kg, bendamustine 90 mg/m², rituximab 375 mg/m² (pola + BR) Q3W for up to six cycles in patients with relapsed/refractory (R/R) diffuse large B‐cell lymphoma (DLBCL) who received ≥1 prior line of therapy and were ineligible for autologous stem cell transplantation (ASCT) or experienced treatment failure with prior ASCT. Primary endpoint was complete response rate (CRR) at the end of the treatment (EOT) by positron emission tomography–computed tomography (PET‐CT) using modified Lugano Response Criteria. Secondary endpoints included efficacy, safety, and pharmacokinetics. Thirty‐five patients (median age 71 [range 46‐86] years) were enrolled. Twenty‐three (66%) patients had refractory disease, and 23 (66%) had ≥2 prior lines of therapy. At a median follow‐up of 5.4 (0.7‐11.9) months, patients received a median of five treatment cycles. CRR was 34.3% (95% confidence interval [CI] 19.1‐52.2) at EOT. Overall response rate was 42.9% at EOT, and median progression‐free survival was 5.2 months (95% CI 3.6‐not evaluable). Median overall survival was not reached. No fatal adverse events (AEs) were observed. Grade 3‐4 AEs were mainly hematological: anemia (37%), neutropenia (31%), white blood cell count decreased (23%), thrombocytopenia/platelet count decreased/neutrophil count decreased (20% each), and febrile neutropenia (11%). Grade 1‐2 peripheral neuropathy (PN; sensory and/or motor) was reported in 14% of patients; there were no ≥grade 3 PN events. This study (JapicCTI‐184048) demonstrated the efficacy and safety of pola + BR in Japanese patients with R/R DLBCL who were ineligible for ASCT.