Phase I trial of radiation therapy and sorafenib in unresectable liver metastases.

BACKGROUND AND PURPOSE: To determine maximum tolerated dose (MTD) and toxicities of sorafenib combined with stereotactic radiotherapy (SBRT) or whole liver radiotherapy (WLRT) in patients with liver metastases.

MATERIAL AND METHODS: Eligible patients had unresectable liver metastases. Sorafenib dose was escalated in 2 strata: I - SBRT: effective liver volume irradiated (Veff )<80% (30-60Gy in 6 fractions); II - WLRT: Veff >80% (21.6Gy in 6 fractions). Four weeks of sorafenib, with radiotherapy during weeks 2-3, was delivered at 3 escalating dose levels (200-400mg twice daily). Dose limiting toxicity was defined as any grade 3+ liver toxicity, or grade 4+ treatment-related toxicity.

RESULTS: Thirty-three patients were treated: 18 in stratum I (median dose 42Gy), 15 in stratum II. The MTD was not reached. Grade 3+ toxicity was seen in 33% of patients, at a median of 10days. Two deaths from non-classic liver toxicity occurred post WLRT in stratum II. The median overall survival was 22.3 and 5.7months for strata I and II respectively.

CONCLUSIONS: Sorafenib and 21.6Gy in 6 fraction WLRT resulted in unacceptably high rates of liver toxicity. Although sorafenib combined with SBRT was tolerable, the observed efficacy does not merit further clinical evaluation.