Model-based treatment optimization of a novel VEGFR inhibitor

AIM

To evaluate dosing and intervention strategies for the phase II programme of a VEGF receptor inhibitor using PK-PD modelling and simulation, with the aim of maximizing (i) the number of patients on treatment and (ii) the average dose level during treatment.

METHODS

A previously developed PK-PD model for lenvatinib (E7080) was updated and parameters were re-estimated (141 patients, once daily and twice daily regimens). Treatment of lenvatinib was simulated for 16 weeks, initiated at 25 mg once daily. Outcome measures included the number of patients on treatment and overall drug exposure. A hypertension intervention design proposed for phase II studies was evaluated, including antihypertensive treatment and dose de-escalation. Additionally, a within-patient dose escalation was investigated, titrating up to 50 mg once daily unless unacceptable toxicity occurred.

RESULTS

Using the proposed antihypertension intervention design, 82% of patients could remain on treatment, and the mean dose administered was 21.5 mg day⁻¹. The adverse event (AE) guided dose titration increased the average dose by 4.6 mg day⁻¹, while only marginally increasing the percentage of patients dropping out due to toxicity (from 18% to 20.8%).

CONCLUSIONS

The proposed hypertension intervention design is expected to be effective in maintaining patients on treatment with lenvatinib. The AE-guided dose titration with blood pressure as a biomarker yielded a higher overall dose level, without relevant increases in toxicity. Since increased exposure to lenvatinib seems correlated with increased treatment efficacy, the adaptive treatment design may thus be a valid approach to improve treatment outcome.

Risk/benefit profile of bevacizumab in metastatic colon cancer: a systematic review and meta-analysis

BACKGROUND

Bevacizumab, an anti vascular endothelial growth factor antibody is licensed in several tumours and widely used in colorectal cancer. However, bevacizumab has several adverse effects which may appear unexpectedly and differ according to the tumour.

AIMS

The aim of this work is to quantify the overall risk of bevacizumab-related side effects in patients affected by advanced colorectal cancer and to compare them with its overall benefit.

METHODS

We performed a systematic review and meta-analysis investigating bevacizumab in metastatic colorectal cancer. Our primary endpoint was safety and secondary endpoints were overall survival and progression-free survival. The relative risks for side effects were calculated with their 95% confidence interval using the inverse of variance method. For statistically significant relative risks, number needed to harm were calculated.

RESULTS

We retrieved six out of 17 eligible papers encompassing 3385 patients. Only hypertension (relative risk 2.98 95% confidence interval 2.32-3.84), gastrointestinal perforations (relative risk 5.04 95% confidence interval 1.72-14.79) and bleeding (relative risk 2.07 95% confidence interval 1.19-3.62) were significantly increased. Bevacizumab significantly improved both overall survival (HR 0.80 95% confidence interval 0.71-0.91) and progression-free survival (hazard ratio (HR) 0.62 95% confidence interval 0.52-0.74). Number needed to treat for overall survival is 12, whilst number needed to harms ranges from 2 to 14.286.

CONCLUSION

These results show that the benefits of the treatment with bevacizumab outweigh the toxicity that may occur: enough to justify its use in advanced colorectal cancer.