Pharmacological properties : תכונות פרמקולוגיות

Pharmacodynamic Properties

5.1   Pharmacodynamic properties
Pharmacotherapeutic group: Antineoplastic agents, other antineoplastic agents, ATC code: not yet assigned

Mechanism of action

Epcoritamab is a humanised IgG1-bispecific antibody that binds to a specific extracellular epitope of CD20 on B cells and to CD3 on T cells. The activity of epcoritamab is dependent upon simultaneous engagement of CD20-expressing cancer cells and CD3-expressing endogenous T cells by epcoritamab that induces specific T-cell activation and T-cell-mediated killing of CD20-expressing cells.

Epcoritamab Fc region is silenced to prevent target-independent immune effector mechanisms, such as antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cellular cytotoxicity (CDC), and antibody-dependent cellular phagocytosis (ADCP).

Pharmacodynamic effects

Epcoritamab induced rapid and sustained depletion of circulating B-cells (defined as CD19 B-cell counts < 10 cell/µl in the subjects who have detectable B cells at treatment initiation). There were 21% subjects (n=33) who had detectable circulating B-cells at treatment initiation. Transient reduction in circulating T cells was observed immediately after each dose in Cycle 1 and followed by T cell expansion in subsequent cycles.


Following subcutaneous administration of epcoritamab, transient and modest elevations of circulating levels of selected cytokines (IFN-γ, TNFα, IL-6, IL-2, and IL-10) occurred mostly after the first full dose (48 mg), with peak levels between 1 to 4 days post dose. Cytokine levels returned to baseline prior to the next full dose, however elevations of cytokines could also be observed after Cycle 1.

Immunogenicity

Anti-drug antibodies (ADA) were commonly detected. The incidence of treatment-emergent ADAs at the approved 48 mg dosing regimen in the target DLBCL population was 2.9% (2.9% positive, 2.9% indeterminate and 94.3% negative, N=140 evaluable patients) and 2.6% (2.6% positive, 2.6% indeterminate and 94.9% negative, N= 39 evaluable patients), in studies GCT3013-01 and GCT3013-04, respectively. No evidence of ADA impact on pharmacokinetics, efficacy or safety was observed, however, data are still limited. Neutralising antibodies were not evaluated.

Clinical efficacy and safety

Study GCT3013-01 was an open-label, multi-cohort, multicentre, single-arm study that evaluated epcoritamab as monotherapy in patients with relapsed or refractory large B-cell lymphoma (LBCL) after two or more lines of systemic therapy, including diffuse large B-cell lymphoma (DLBCL). The study includes a dose escalation part and an expansion part. The expansion part of the study included an aggressive non-Hodgkin lymphoma (aNHL) cohort, an indolent NHL (iNHL) cohort and a mantle-cell lymphoma (MCL) cohort. The pivotal aNHL cohort consisted of patients with LBCL (N=157), including patients with DLBCL (N=139, 12 patients of which had MYC, BCL2, and/or BCL6 rearrangements i.e., DH/TH), with high-grade B-cell lymphoma (HGBCL) (N=9), with follicular lymphoma grade 3B (FL) (N=5) and patients with primary mediastinal B-cell lymphoma (PMBCL) (N=4). In the DLBCL cohort, 29% (40/139) of patients had transformed DLBCL arising from indolent lymphoma. Patients included in the study were required to have documented CD20+ mature B-cell neoplasm according to WHO classification 2016 or WHO classification 2008 based on representative pathology report, failed prior autologous hematopoietic stem cell transplantation (HSCT) or were ineligible for autologous HSCT, patients who had lymphocyte counts < 5×109/L, and patients with at least 1 prior anti-CD20 monoclonal antibody-containing therapy.
The study excluded patients with central nervous system (CNS) involvement of lymphoma, prior treatment with allogeneic HSCT or solid organ transplant, chronic ongoing infectious diseases, any patients with known impaired T-cell immunity, a creatinine clearance of less than 45 ml/min, alanine aminotransferase > 3 times the upper limit of normal, cardiac ejection fraction less than 45%, and known clinically significant cardiovascular disease. Efficacy was evaluated in 139 patients with DLBCL who had received at least one dose of epcoritamab SC in cycles of 4 weeks, i.e., 28 days. Epcoritamab monotherapy was administered as follows:

•   Cycle 1: epcoritamab 0.16 mg on Day 1, 0.8 mg on Day 8, 48 mg on Day 15 and Day 22 •   Cycles 2-3: epcoritamab 48 mg on Days 1, 8, 15, and 22
•   Cycles 4-9: epcoritamab 48 mg on Days 1 and 15
•   Cycles 10 and beyond: epcoritamab 48 mg on Day 1

Patients continued to receive epcoritamab until disease progression or unacceptable toxicity.

The demographics and baseline characteristics are shown in Table 7.

Table 7 Demographics and baseline characteristics of patients with DLBCL in GCT3013-01 study 
Characteristics                                                                   (N=139) Age
Median, years (min, max)                                                    66 (22, 83) < 65 years, n (%)                                                                 66 (47) 65 to < 75 years, n (%)                                                           44 (32) ≥ 75 years, n (%)                                                                 29 (21) Males, n (%)                                                                      85 (61) Race, n (%)
White                                                                         84 (60) Asian                                                                         27 (19) Other                                                                          5 (4) Not Reported                                                                 23 (17) ECOG performance status; n (%)
0                                                                             67 (48) 1                                                                             67 (48) 2                                                                              5 (4)
Disease stagec at initial diagnosis, n (%)
III                                                                               16 (12) IV                                                                                86 (62) Number of prior lines of anti-lymphoma therapy

Median (min, max)                                                            3 (2, 11) 2, n (%)                                                                      41 (30)
3, n (%)                                                                      47 (34) ≥ 4, n (%)                                                                     51 (37) DLBCL Disease history; n (%)
De Novo DLBCL                                                                   97 (70) DLBCL transformed from indolent lymphoma                                        40 (29) FISH Analysis Per Central labd, N=88
Double-hit/Triple-hit lymphoma, n (%)                                          12 (14) Prior autologous HSCT                                                             26 (19) Prior therapy; n (%)
Prior CAR-T                                                                   53 (38) Primary refractory diseasea                                                     82 (59) Refractory to ≥ 2 consecutive lines of prior anti-lymphoma                     104 (75) therapyb
Refractory to the last line of systemic antineoplastic therapyb                114 (82) Refractory to prior anti-CD20 therapy                                          117 (84) Refractory to CAR-T                                                             39 (28) a
A patient is considered to be primary refractory if the patient is refractory to frontline anti-lymphoma therapy.
b
A patient is considered to be refractory if the patient either experiences disease progression during therapy or disease progression within < 6 months after therapy completion. A patient is considered relapsed if the patient had recurred disease ≥ 6 months after therapy completion.
c
Per Ann Arbor Staging.

d
Post hoc central lab FISH analysis was performed on available diagnostic baseline tumour tissue sections from 88 DLBCL patients.

The primary efficacy endpoint was overall response rate (ORR) determined by Lugano criteria (2014) as assessed by Independent Review Committee (IRC). The median follow-up time was 10.7 months (range: 0.3 to 17.9 months). The median duration of exposure was 4.1 months (range: 0 to 18 months).

Table 8 Efficacy results in study GCT3013-01 in patients with DLBCLa

Endpoint                                 Epcoritamab
IRC assessment                                (N=139)
ORRb, n (%)                                                        86 (62) (95% CI)                                                     (53.3, 70) CRb, n (%)                                                      54 (39) (95% CI)                                                    (30.7, 47.5) PR, n (%)                                                       32 (23) (95% CI)                                                     (16.3, 30.9) DORb
Median (95% CI), months                                  15.5 (9.7, NR) b
DOCR
Median (95% CI), months                                       NR (12.0, NR) TTR, median (range), months                                     1.4 (1, 8.4) CI = confidence interval; CR = complete response; DOR = duration of response; DOCR = duration of complete response; IRC = independent review committee; ORR = overall response rate; PR = partial response; TTR = time to response a
Determined by Lugano criteria (2014) as assessed by independent review committee (IRC) b
Included patients with initial PD by Lugano or IR by LYRIC who later obtained PR/CR.

The median time to CR was 2.6 months (range: 1.2 to 10.2 months).

Pharmacokinetic Properties

5.2   Pharmacokinetic properties
The population pharmacokinetics following subcutaneous administration of epcoritamab was described by a two-compartment model with first order subcutaneous absorption and target-mediated drug elimination. The moderate to high pharmacokinetic variability for epcoritamab was observed and characterised by inter-individual variability (IIV) ranging from 25.7% to 137.5% coefficient of variation (CV) for epcoritamab PK parameters.

Based on individually estimated exposures using population pharmacokinetic modelling, following the recommended SC dose of epcoritamab 48 mg, the geometric mean (% CV) Cmax of epcoritamab is 10.8 mcg/ml (41.7%) and AUC0-7d is 68.9 day*mcg/ml (45.1%) at the end of the weekly dosing schedule. The Ctrough at Week 12 is 8.4 (53.3%) mcg/ml.

The geometric mean (% CV) Cmax of epcoritamab is 7.52 mcg/ml (41.1%) and AUC0-14d is 82.6 day*mcg/ml (49.3%) at the end of q2w schedule. The Ctrough for q2W schedule is 4.1 (73.9%) mcg/ml.


The geometric mean (% CV) Cmax of epcoritamab is 4.76 mcg/ml (51.6%) and AUC0-28d is 74.3 day*mcg/ml (69.5%) at steady state during the q4w schedule. The Ctrough for q4W schedule is 1.2 (130%) mcg/ml.

Absorption

The peak concentrations occurred around 3-4 days (Tmax) in patients with LBCL receiving the 48 mg full dose.

Distribution

The geometric mean (% CV) central volume of distribution is 8.27 l (27.5%) and apparent steady-state volume of distribution is 25.6 l (81.8%) based on population PK modelling.

Biotransformation

The metabolic pathway of epcoritamab has not been directly studied. Like other protein therapeutics, epcoritamab is expected to be degraded into small peptides and amino acids via catabolic pathways.

Elimination

Epcoritamab is expected to undergo saturable target mediated clearance. The geometric mean (% CV) clearance (l/day) is 0.441 (27.8%). The half-life of epcoritamab is concentration dependent. The population PK model-derived geometric mean half-life of full dose epcoritamab (48 mg) ranged from 22 to 25 days based on frequency of dosing.

Special populations

No clinically important effects on the pharmacokinetics of epcoritamab (Cycle 1 AUC within approximately 36%) were observed based on age (20 to 89 years), sex, or race/ethnicity (white, Asian, and other), mild to moderate renal impairment creatinine clearance (CLcr ≥ 30 ml/min to CLcr < 90 ml/min), and mild hepatic impairment (total bilirubin ≤ ULN and AST > ULN, or total bilirubin 1 to 1.5 times ULN and any AST) after accounting for differences in bodyweight. No patients with severe to end-stage renal disease (CLcr < 30 ml/min) or severe hepatic impairment (total bilirubin > 3 times ULN and any AST) have been studied. There is very limited data in moderate hepatic impairment (total bilirubin > 1.5 to 3 times ULN and any AST, N=1). Therefore, the pharmacokinetics of epcoritamab is unknown in these populations.

Like other therapeutic proteins, body weight (39 to 144 kg) has a statistically significant effect on the pharmacokinetics of epcoritamab. Based on exposure-response analysis and clinical data, considering the exposures in patients at either low body weight (e.g., 46 kg) or high body weight (e.g., 105 kg) and across body weight categories (< 65 kg, 65-< 85, ≥ 85), the effect on exposures is not clinically relevant.

Paediatric population

The pharmacokinetics of epcoritamab in paediatric patients has not been established.