Molecularly targeted therapy in hepatocellular carcinoma

With an annual incidence of over 660,000 deaths, hepatocellular carcinoma (HCC) is the third leading cause of cancer death globally. This disease is often diagnosed at an advanced stage, when potentially curative therapies are not feasible. HCC is highly resistant to conventional systemic therapies and prognosis for advanced HCC patients remains poor. Given the clear need, clinical development of novel therapeutic agents in HCC has begun in earnest. Our recent knowledge of the molecular mechanisms responsible of tumor initiation and progression has identified several potential molecular targets in HCC. These targets are the receptor tyrosine kinase-activated pathways, which include the Raf/MEK/ERK, PI-3K/Akt/mTOR, and Jak/Stat. Sorafenib is the multikinase inhibitor that has shown modest survival benefits in advanced HCC in two randomized controlled trials, supporting the use of molecularly targeted therapies in treatment of HCC. A number of strategies including monoclonal antibodies and tyrosine kinase inhibitors such as erlotinib, sunitinib, vandetanib, cediranib, brivanib, foretinib, and dovitinib have been developed and tested in various phases of clinical trials. The successful development of these novel targeted agents in the future will be dependent on the selection of patient populations that are most likely to derive clinical benefit, optimization of the dose used and schedules, and investigation of combined therapies. This review describes evolving molecular targeted agents, their common adverse side effects, and its potential use in management of HCC.

K-ras mutations and benefit from cetuximab in advanced colorectal cancer

BACKGROUND

Treatment with cetuximab, a monoclonal antibody directed against the epidermal growth factor receptor, improves overall and progression-free survival and preserves the quality of life in patients with colorectal cancer that has not responded to chemotherapy. The mutation status of the K-ras gene in the tumor may affect the response to cetuximab and have treatment-independent prognostic value.

METHODS

We analyzed tumor samples, obtained from 394 of 572 patients (68.9%) with colorectal cancer who were randomly assigned to receive cetuximab plus best supportive care or best supportive care alone, to look for activating mutations in exon 2 of the K-ras gene. We assessed whether the mutation status of the K-ras gene was associated with survival in the cetuximab and supportive-care groups.

RESULTS

Of the tumors evaluated for K-ras mutations, 42.3% had at least one mutation in exon 2 of the gene. The effectiveness of cetuximab was significantly associated with K-ras mutation status (P=0.01 and P<0.001 for the interaction of K-ras mutation status with overall survival and progression-free survival, respectively). In patients with wild-type K-ras tumors, treatment with cetuximab as compared with supportive care alone significantly improved overall survival (median, 9.5 vs. 4.8 months; hazard ratio for death, 0.55; 95% confidence interval [CI], 0.41 to 0.74; P<0.001) and progression-free survival (median, 3.7 months vs. 1.9 months; hazard ratio for progression or death, 0.40; 95% CI, 0.30 to 0.54; P<0.001). Among patients with mutated K-ras tumors, there was no significant difference between those who were treated with cetuximab and those who received supportive care alone with respect to overall survival (hazard ratio, 0.98; P=0.89) or progression-free survival (hazard ratio, 0.99; P=0.96). In the group of patients receiving best supportive care alone, the mutation status of the K-ras gene was not significantly associated with overall survival (hazard ratio for death, 1.01; P=0.97).

CONCLUSIONS

Patients with a colorectal tumor bearing mutated K-ras did not benefit from cetuximab, whereas patients with a tumor bearing wild-type K-ras did benefit from cetuximab. The mutation status of the K-ras gene had no influence on survival among patients treated with best supportive care alone. (ClinicalTrials.gov number, NCT00079066.)