ime to disease progression, Median months
5.6
7.1
0.70 (0.58-0.85)
0.0003
Overall response rate,%
34.5%
47.3%
1.70a (1.22, 2.38)
0.0017
Duration of response, median months
4.8
6.9
0.54 (0.40-0.73)
< 0.0001
FP + H: Fluoropyrimidine/cisplatin + trastuzumab
FP: Fluoropyrimidine/cisplatin
a Odds ratio
Patients were recruited to the trial who were previously untreated for HER2-positive inoperable locally advanced or recurrent and/or metastatic adenocarcinoma of the stomach or gastro-oesophageal junction not amenable to curative therapy. The primary endpoint was overall survival which was defined as the time from the date of randomisation to the date of death from any cause. At the time of the analysis a total of 349 randomised patients had died: 182 patients (62.8%) in the control arm and 167 patients (56.8%) in the treatment arm. The majority of the deaths were due to events related to the underlying cancer.
Post-hoc subgroup analyses indicate that positive treatment effects are limited to targeting tumours with higher levels of HER2 protein (IHC 2+/FISH+ or IHC 3+). The median overall survival for the high HER2 expressing group was 11.8 months versus 16 months, HR 0.65 (95% CI 0.51-0.83) and the median progression free survival was 5.5 months versus 7.6 months, HR 0.64 (95% CI 0.51-0.79) for FP versus FP + H, respectively. For overall survival, the HR was 0.75 (95% CI 0.51-1.11) in the IHC 2+/FISH+ group and the HR was 0.58 (95% CI 0.41-0.81) in the IHC 3+/FISH+ group.
In an exploratory subgroup analysis performed in the TOGA (BO18255) trial there was no apparent benefit on overall survival with the addition of trastuzumab in patients with ECOG PS 2 at baseline [HR 0.96 (95% CI 0.51-1.79)], non measurable [HR 1.78 (95% CI 0.87-3.66)] and locally advanced disease [HR 1.20 (95% CI 0.29-4.97)].
Paediatric population
The European Medicines Agency has waived the obligation to submit the results of studies with trastuzumab in all subsets of the paediatric population in breast and gastric cancer (see section 4.2 for information on paediatric use).
5.2 Pharmacokinetic properties
The pharmacokinetics of trastuzumab were eva luated in a population pharmacokinetic model analysis using pooled data from 1,582 subjects, including patients with HER2 positive MBC, EBC, AGC or other tumour types, and healthy volunteers, in 18 Phase I, II and III trials receiving trastuzumab intravenously. A two-compartment model with parallel linear and non-linear elimination from the central compartment described the trastuzumab concentration-time profile. Due to non-linear elimination, total clearance increased with decreasing concentration. Therefore, no constant value for half-life of trastuzumab can be deduced. The t1/2 decreases with decreasing concentrations within a dosing interval (see Table 16). MBC and EBC patients had similar PK parameters (e.g. clearance (CL), the central compartment volume (Vc)) and population-predicted steady-state exposures (Cmin, Cmax and AUC). Linear clearance was 0.136 L/day for MBC, 0.112 L/day for EBC and 0.176 L/day for AGC. The non-linear elimination parameter values were 8.81 mg/day for the maximum elimination rate (Vmax) and 8.92 μg/mL for the Michaelis-Menten constant (Km) for the MBC, EBC, and AGC patients. The central compartment volume was 2.62 L for patients with MBC and EBC and 3.63 L for patients with AGC. In the final population PK model, in addition to primary tumour type, body weight, serum aspartate a |
