SYDNEY, AUSTRALIA – Cetuximab does not improve overall survival when used alongside chemoradiotherapy in patients with unresectable stage III lung cancer, based on data from a randomized, phase III comparison trial.
Cetuximab also appeared to be associated with an increase in therapy-related toxicities, based on data presented during a plenary session of a world conference on lung cancer.
The RTOG 0617 trial is an intergroup trial comparing standard-dose (60 Gy) and high-dose (74 Gy) radiotherapy and standard chemotherapy with and without cetuximab in patients with newly diagnosed, unresectable stage IIIA/IIIB non–small cell lung cancer.
Median survival in patients randomized to cetuximab was 23.1 months, compared with 23.5 months in patients not taking cetuximab; overall survival at 18 months was 60.8% versus 60.2% on the cetuximab and noncetuximab arms, respectively (P = .484; hazard ratio, 0.99), based on data from 465 patients.
There were 167 therapy-related grade 3 nonhematologic adverse events reported in the cetuximab group, compared with 115 in the no-cetuximab group (P less than .0001).
There was no significant interaction between radiation dose and cetuximab, although preliminary analysis did suggest that cetuximab may have more beneficial effect in patients with high-EGFR expression.
Presenting author Dr. Gregory Masters said that cetuximab – a monoclonal antibody used in head and neck, and colon cancer – had shown some survival benefit in previous studies in patients with more advanced lung cancer.
"If a drug shows an effect in stage IV patients, where you may only improve survival by a few months, hopefully you can then translate that into more cures for earlier-stage patients," said Dr. Masters, medical oncologist at the Helen F. Graham Cancer Centre in Newark, Del.
"In fact, we saw more toxicity and we didn’t show a treatment effect, at least in the overall population," Dr. Masters said in an interview at the meeting, which was sponsored by the International Association for the Study of Lung Cancer.
The trial was originally designed to compare high and low-dose radiotherapy; cetuximab was added after other studies suggested promising results in combination with chemotherapy and radiotherapy.
Results from the standard and high-dose radiotherapy analysis of the trial were presented at the annual meeting of the American Society of Clinical Oncology in May of this year and showed no advantage with increased radiation dose.
The study received support from Bristol-Myers Squibb and Eli Lilly, but no other financial conflicts of interest were declared.