Time-to-event modelling of effect of codrituzumab on overall survival in patients with hepatocellular carcinoma

Aims

Codrituzumab (GC33) is a recombinant, humanized mAb that binds to glypican-3 (GPC3), an oncofoetal protein highly expressed in hepatocellular carcinoma (HCC). This investigation aimed to identify clinically relevant factors that may affect the overall survival (OS) in HCC patients treated with codrituzumab and to quantitatively annotate their effects.

Methods

Codrituzumab exposure was estimated by a population pharmacokinetics model with a non-linear elimination pathway. Analysis of OS was performed using a time-to-event model in 181 patients with advanced HCC. The model was tested with addition of various covariates, including levels of immune biomarkers, such as CD16 (measured in terms of molecules of equivalent soluble fluorophore; CD16_MESF) and CD4, codrituzumab exposure, and potential prognostic biomarkers of HCC such as baseline tumour size, and soluble GPC3.

Results

The time-to-event model estimated a prolonged OS (>3 months) in patients with codrituzumab exposure of ≥230 μg/mL and high CD16_MESF level (>5.26 × 10⁵ MESF at least). The Weibull model was selected as the base hazard model. The baseline tumour size was included in the hazard model as a parameter independent of the drug effect. A logistic model was applied to explain the effects of drug exposure and CD16_MESF level.

Conclusions

The final model indicates that adequate drug exposure plus a favourable immune environment are associated with prolonged OS. This quantitative model should be further validated with emerging data so as to guide study design in future clinical trials.

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