Pharmacotherapeutic group: Monoclonal antibodies and antibody drug conjugates.
ATC code: L01FX18.
Pharmacology: Pharmacodynamics: Mechanism of action: Amivantamab is a low-fucose, fully-human IgG1-based EGFR-MET bispecific antibody with immune cell-directing activity that targets tumours with activating EGFR mutations such as Exon 19 deletions, L858R substitution, and Exon 20 insertion mutations. Amivantamab binds to the extracellular domains of EGFR and MET.
Amivantamab disrupts EGFR and MET signalling functions through blocking ligand binding and enhancing degradation of EGFR and MET, thereby preventing tumour growth and progression. The presence of EGFR and MET on the surface of tumour cells also allows for targeting of these cells for destruction by immune effector cells, such as natural killer cells and macrophages, through antibody-dependent cellular cytotoxicity (ADCC) and trogocytosis mechanisms, respectively.
Pharmacodynamic effects: Albumin: Amivantamab decreased serum albumin concentration, a pharmacodynamic effect of MET inhibition, typically during the first 8 weeks (see Adverse Reactions); thereafter, albumin concentration stabilised for the remainder of amivantamab treatment.
Clinical efficacy and safety: Previously treated NSCLC with EGFR Exon 19 deletions or Exon 21 L858R substitution mutations (MARIPOSA-2): MARIPOSA-2 is a randomised (2:2:1) open-label, multicentre Phase 3 study in patients with locally advanced or metastatic NSCLC with EGFR Exon 19 deletions or Exon 21 L858R substitution mutations (mutation testing could have been performed at or after the time of locally advanced or metastatic disease diagnosis. Testing did not need to be repeated at the time of study entry once EGFR mutation status was previously established) after failure of prior therapy including a third-generation EGFR tyrosine kinase inhibitor (TKI). A total of 657 patients were randomised in the study, of which 263 received carboplatin and pemetrexed (CP); and 131 which received RYBREVANT in combination with carboplatin and pemetrexed (RYBREVANT-CP). Additionally, 236 patients were randomised to receive RYBREVANT in combination with lazertinib, carboplatin, and pemetrexed in a separate arm of the study. RYBREVANT was administered intravenously at 1400 mg (for patients <80 kg) or 1750 mg (for patients ≥80 kg) once weekly through 4 weeks, then every 3 weeks with a dose of 1750 mg (for patients <80 kg) or 2100 mg (for patients ≥80 kg) starting at Week 7 until disease progression or unacceptable toxicity. Carboplatin was administered intravenously at area under the concentration-time curve 5 mg/mL per minute (AUC 5) once every 3 weeks, for up to 12 weeks. Pemetrexed was administered intravenously at 500 mg/m2 on once every 3 weeks until disease progression or unacceptable toxicity.
Patients were stratified by osimertinib line of therapy (first-line or second-line), prior brain metastases (yes or no), and Asian race (yes or no).
Of the 394 patients randomised to the RYBREVANT-CP arm or CP arm, the median age was 62 (range: 31-85) years, with 38% of the patients ≥65 years of age; 60% were female; and 48% were Asian and 46% were White. Baseline Eastern Cooperative Oncology Group (ECOG) performance status was 0 (40%) or 1 (60%); 66% never smoked; 45% had history of brain metastasis, and 92% had Stage IV cancer at initial diagnosis.
RYBREVANT in combination with carboplatin and pemetrexed demonstrated a statistically significant improvement in progression-free survival (PFS) compared to carboplatin and pemetrexed, with a HR of 0.48 (95% CI: 0.36, 0.64; p<0.0001). At the time of the second interim analysis for OS, with a median follow-up of approximately 18.6 months for RYBREVANT-CP and approximately 17.8 months for CP, the OS HR was 0.73 (95%CI: 0.54, 0.99; p=0.0386). This was not statistically significant (tested at a prespecified significance level of 0.0142).
Efficacy results are summarised in Table 1. (See Table 1 and Figure 1.)
Click on icon to see table/diagram/image
Click on icon to see table/diagram/image
The PFS benefit of RYBREVANT-CP compared to CP was consistent across all the predefined subgroups analysed, including ethnicity, age, gender, smoking history, and CNS metastases status at study entry. (See Figure 2.)
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Intracranial metastases efficacy data: Patients with asymptomatic or previously treated and stable intracranial metastases were eligible to be randomised in MARIPOSA-2. Treatment with RYBREVANT-CP was associated with a numeric increase in intracranial ORR (23.3% for RYBREVANT-CP versus 16.7% for CP, odds ratio of 1.52; 95% CI (0.51, 4.50), and intracranial DOR (13.3 months; 95% CI (1.4, NE) in the RYBREVANT-CP arm compared with 2.2 months; 95% CI (1.4, NE) in the CP arm). The median follow-up for RYBREVANT-CP was approximately 18.6 months.
Locally advanced or metastatic NSCLC with exon 20 insertion mutations: Previously-untreated NSCLC: NSC3001 (PAPILLON) is a randomized, open-label, multicenter phase 3 study comparing treatment with RYBREVANT in combination with carboplatin and pemetrexed to treatment as compared to chemotherapy alone (carboplatin and pemetrexed) in subjects with treatment-naïve, locally advanced or metastatic NSCLC with EGFR Exon 20 insertion mutations, as identified by local testing, plasma samples from 209/308 (67.9%) patients were tested retrospectively using Guardant360 CDx, identifying 155/209 (74.2%) samples with an EGFR exon 20 insertion mutation; 50/209 (23.9%) samples did not have an EGFR exon 20 insertion mutation identified. The remaining 4/209 (1.9%) samples generated an invalid test result.
Tumor tissue (92.2%) and/or plasma (7.8%) samples for all 308 patients were tested locally to determine EGFR Exon 20 insertion mutation status using next generation sequencing (NGS) in 55.5% of patients and/or polymerase chain reaction (PCR) in 44.5% of patients.
Patients with brain metastases at screening were eligible for participation once they were definitively treated, clinically stable, asymptomatic, and off corticosteroid treatment for at least 2 weeks prior to randomization. Patients with a medical history of ILD, drug induced ILD, radiation pneumonitis that required steroid treatment, or any evidence of clinically active ILD were excluded from the clinical study.
RYBREVANT was administered intravenously at 1,400 mg (for subjects <80 kg) or 1,750 mg (for subjects ≥80 kg) once weekly through 4 weeks, then every 3 weeks with a dose of 1,750 mg (for patients <80 kg) or 2,100 mg (for subjects ≥80 kg) starting at Week 7 until disease progression or unacceptable toxicity. Carboplatin was administered intravenously at area under the concentration-time curve 5 mg/mL per minute (AUC 5) once every 3 weeks, for up to 12 weeks. Pemetrexed was administered intravenously at 500 mg/m2 on once every 3 weeks until disease progression or unacceptable toxicity. Randomization was stratified by ECOG performance status, prior brain metastases, and prior EGFR TKI use. Subjects randomized to the carboplatin and pemetrexed arm who had confirmed disease progression were permitted to cross over to receive RYBREVANT monotherapy.
A total of 308 subjects were randomized (1:1) to RYBREVANT in combination with carboplatin and pemetrexed (N=153) or carboplatin and pemetrexed (N=155). The median age was 62 (range: 27 to 92) years, with 39% of the subjects ≥65 years of age; 58% were female; and 61% were Asian and 36% were White. Baseline Eastern Cooperative Oncology Group (ECOG) performance status was 0 (35%) or 1 (65%); 58% never smoked; 23% had history of brain metastasis and 84% had Stage IV cancer at initial diagnosis.
RYBREVANT in combination with carboplatin and pemetrexed demonstrated a clinically meaningful and statistically significant improvement in progression-free survival (PFS) compared to carboplatin and pemetrexed, with a HR of 0.40 (95% CI: 0.30, 0.53; p<0.0001), demonstrating a 61% reduction in the risk of disease progression or death in the patients. At the time of primary analysis, overall survival showed a strong trend suggestive of a survival benefit in favor of the RYBREVANT-treated arm, where 65 subjects (42%) randomized to receive carboplatin and pemetrexed crossed over to receive RYBREVANT monotherapy (see Figure 5). A greater proportion of patients treated with RYBREVANT in combination with carboplatin and pemetrexed were alive at 12 months and 18 months (74% and 72%, respectively) compared to patients treated with carboplatin and pemetrexed (68% and 54%, respectively). Analyses of post-progression endpoints demonstrated that PFS benefit was preserved through subsequent lines of therapy, with a median follow-up of 14.9 (range: 0.3 to 27.0) months.
Efficacy results for Study 3001 are summarized in Table 2, Figure 3 and Figure 4. (See Table 2 and Figure 3.)
Click on icon to see table/diagram/image
Click on icon to see table/diagram/image
The pre-planned sensitivity analysis evaluating PFS as assessed by the treating investigator showed a 62% reduction in the risk of disease progression or death (median 12.9 months) in participants randomized to the RYBREVANT in combination with carboplatin and pemetrexed arm (HR of 0.38 [95% CI: 0.29, 0.52, nominal p<0.001]), consistent with that observed in the BICR assessment of PFS.
Additionally, consistent with the assessment by BICR, results of the DOR and ORR analysis based on the treating investigator's assessment also showed a significant treatment benefit with RYBREVANT in combination with carboplatin and pemetrexed. The median DOR was 15.28 months (95% CI: 10.87, NE) and the ORR analysis showed significantly improved anti-tumor activity with an ORR of 66.0% (95% CI: 57.9, 73.5).
The PFS benefit of RYBREVANT in combination with carboplatin and pemetrexed compared to carboplatin and pemetrexed was consistent across the predefined subgroups of brain metastases at study entry (yes or no), age (<65 or ≥65), sex (male or female), race (Asian or non-Asian), weight (<80 kg or ≥80 kg), ECOG performance status (0 or 1), and smoking history (yes or no). See Figure 4. (See Figures 4 and 5.)
Click on icon to see table/diagram/image
Click on icon to see table/diagram/image
Patient Reported Outcomes: Patient-reported symptoms and health-related quality of life (HRQoL) were electronically collected using the EORTC QLQ-C30 and PROMIS-PF. These instruments were administered approximately once every 6 weeks until end of treatment. They were then administered 30 days after last dose of treatment, then once every 12 weeks for one year. Compliance was high at baseline (>97%) and during treatment (>80% through Cycle 31) in both arms. At baseline, patients in both treatment arms reported low symptom burden and high levels of functioning.
The PRO analyses demonstrated that the clinical benefits of receiving RYBREVANT with carboplatin and pemetrexed were achieved without compromising HRQoL. Across all PRO scales, patients’ baseline HRQoL was maintained while on treatment in both arms.
Time to deterioration analyses showed that median time to symptom worsening was delayed by 2 to 5 months for RYBREVANT with carboplatin and pemetrexed compared to carboplatin and pemetrexed alone for dyspnea (HR=0.75, 95% CI: 0.55, 1.01), pain (HR=0.74, 95% CI: 0.55, 1.00), insomnia (HR=0.75, 95% CI: 0.54, 1.04), diarrhea (HR=0.67, 95% CI: 0.47, 0.95), and nausea/vomiting (HR=0.74, 95% CI: 0.55, 0.98).
Previously-treated NSCLC: EDI1001 (CHRYSALIS) is a multicenter, open-label, multi-cohort study conducted to assess the safety and efficacy of RYBREVANT in subjects with locally advanced or metastatic NSCLC. Efficacy was evaluated in 81 subjects with locally advanced or metastatic NSCLC who had EGFR Exon 20 insertion mutations as determined by previous local standard of care testing, whose disease had progressed on or after platinum-based chemotherapy, and who had median follow-up of 9.7 months. RYBREVANT was administered intravenously at 1050 mg for subjects <80 kg or 1400 mg for subjects ≥80 kg once weekly for 4 weeks, then every 2 weeks starting at Week 5 until disease progression or unacceptable toxicity.
The median age was 62 (range: 42–84) years, with 9% of the subjects ≥75 years of age; 59% were female; and 49% were Asian and 37% were White. The median number of prior therapies was 2 (range: 1 to 7 therapies). At baseline, 99% had Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 (99%); 53% never smoked; 75% had Stage IV cancer; and 22% had previous treatment for brain metastases. Insertions in Exon 20 were observed at 8 different residues; the most common residues were A767 (24%), S768 (16%), D770 (11%), and N771 (11%).
Efficacy results are summarized in Table 3. (See Table 3.)
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Anti-tumor activity was observed across all mutation variants.
Elderly: No overall differences in effectiveness were observed between patients ≥65 years of age and patients <65 years of age.
Pharmacokinetics: Based on RYBREVANT monotherapy data, amivantamab area under the concentration-time curve (AUC1 week) increases proportionally over a dose range from 350 to 1750 mg.
Based on simulations from the population pharmacokinetic model, AUC1 week was approximately 2.8-fold higher after the fifth dose for the 2-week dosing regimen and 2.6-fold higher after the fourth dose for the 3-week dosing regimen. Steady-state concentrations of amivantamab were reached by Week 13 for both the 3-week and 2-week dosing regimen and the systemic accumulation was 1.9-fold.
Distribution: Based on the individual amivantamab PK parameter estimates in population PK analysis, the geometric mean (CV%) total volume of distribution, is 5.12 (27.8%) L, following administration of the recommended dose of RYBREVANT.
Elimination: Based on the individual amivantamab PK parameter estimates in population PK analysis, the geometric mean (CV%) linear clearance (CL) and terminal half-life associated with linear clearance is 0.266 (30.4%) L/day and 13.7 (31.9%) days respectively.
Special populations: Elderly: No clinically meaningful differences in the pharmacokinetics of amivantamab were observed based on age (27-87 years).
Renal impairment: No clinically meaningful effect on the pharmacokinetics of amivantamab was observed in patients with mild (≤60 creatinine clearance [CrCl] <90 mL/min) and moderate (≤29 CrCl <60 mL/min) renal impairment. The effect of severe renal impairment (≤15 CrCl <29 mL/min) on amivantamab pharmacokinetics is unknown.
Hepatic impairment: Changes in hepatic function are unlikely to have any effect on the elimination of amivantamab since IgG1-based molecules such as amivantamab are not metabolised through hepatic pathways.
No clinically meaningful effect in the pharmacokinetics of amivantamab was observed based on mild hepatic impairment [(total bilirubin ≤ ULN and AST > ULN) or (ULN < total bilirubin ≤1.5 x ULN)]. The effect of moderate (total bilirubin 1.5 to 3 times ULN) and severe (total bilirubin >3 times ULN) hepatic impairment on amivantamab pharmacokinetics is unknown.
Paediatric population: The pharmacokinetics of RYBREVANT in paediatric patients have not been investigated.
Toxicology: Preclinical safety data: Non-clinical data reveal no special hazard for humans based on conventional studies of repeated dose toxicity.
Carcinogenicity and mutagenicity: No animal studies have been performed to establish the carcinogenic potential of amivantamab. Routine genotoxicity and carcinogenicity studies are generally not applicable to biologic pharmaceuticals as large proteins cannot diffuse into cells and cannot interact with DNA or chromosomal material.
Reproductive toxicology: No animal studies have been conducted to evaluate the effects on reproduction and foetal development; however, based on its mechanism of action, amivantamab can cause foetal harm or developmental anomalies. As reported in the literature, reduction, elimination, or disruption of embryo foetal or maternal EGFR signaling can prevent implantation, cause embryo foetal loss during various stages of gestation (through effects on placental development), cause developmental anomalies in multiple organs or early death in surviving foetuses. Similarly, knock out of MET or its ligand hepatocyte growth factor (HGF) was embryonic lethal due to severe defects in placental development, and foetuses displayed defects in muscle development in multiple organs. Human IgG1 is known to cross the placenta; therefore, amivantamab has the potential to be transmitted from the mother to the developing foetus.