Merck KGaA’s Erbitux helped patients live longer than Roche Holding AG’s Avastin, a more commonly prescribed treatment, in a head-to-head test of the two drugs in patients with metastatic colon cancer.
Patients who got Erbitux together with chemotherapy as a first-line treatment lived about four months longer than those who got Avastin with chemotherapy, according to the 592-person study, dubbed Fire-3, presented today at the American Society of Clinical Oncology’s meeting in Chicago. Merck, based in Darmstadt, Germany, sponsored the trial.
While unlikely to change doctors’ prescribing behavior alone, the unexpected results may focus attention on a bigger Erbitux-versus-Avastin study due next year, said Axel Grothey, a professor of oncology at the Mayo Clinic in Rochester, Minnesota. Both drugs are approved as initial therapies in colon cancer in the U.S., though Avastin is used more often, he said.
“If we see the same finding in this study, then I think it’s real,” Grothey said, referring to next year’s follow-up trial. “If we don’t see this result, then the Fire-3 trial is more or less a fluke. Before I would change my standard of care I would wait for these results.”
Patients lived about the same amount of time before their disease worsened, 10 months compared to 10.3 months, in the Erbitux and Avastin arms of the trial. Overall response rate, or shrinkage of tumors, the trial’s main data endpoint, were also the same.
The survival results emerged more than a year after most patients had stopped taking either drug, as the group that got initial treatment with Erbitux lived a median 28.7 months, compared to 25 months for those taking Avastin. The study only included the roughly 60 percent of colon cancer patients whose tumors have the non-mutated KRAS gene that makes Erbitux more likely to be effective.
Outcomes could have been influenced by differing access to therapies once initial treatment was over, Mayo’s Grothey said.
Though he wasn’t involved with the trial itself, Grothey will serve as chairman this weekend for a combined advisory board on the study for Erbitux partners Merck, Bristol-Myers Squibb Co. and Eli Lilly & Co.
“These results are intriguing, but an unexplained positive finding from a secondary endpoint will not influence U.S. practice patterns,” Scott Kopetz, an associate professor of gastrointestinal medical oncology at the University of Texas MD Anderson Cancer Center, said in an e-mail.
About half the patients in each arm of the study switched to the opposite medicine -- from Erbitux to Avastin, or vice versa -- as a second treatment once their cancer had worsened, said Volker Heinemann, a professor of medical oncology at the Ludwig Maximilian University of Munich and lead author of the study. Full data on the treatment patients got once their cancer had worsened will be presented at the World Congress on Gastrointestinal Cancer in July, Heinemann said.
The results show that doctors who treat patients with the unmutated KRAS gene should choose Erbitux over Avastin, Heinemann said.
“For the moment we have to remain at that conclusion,” he said. “We are going to wait for support from the larger study. For the moment that is a reasonable conclusion.”
Roche looks forward to seeing full details of the study presented at the conference later today, spokesman Daniel Grotzky said in an e-mail before the results were released. Avastin is the Basel, Switzerland-based company’s third-biggest drug, with about $6 billion in sales last year.
Erbitux generated sales for Merck of 887 million euros ($1.15 billion) last year, with the majority of the revenue from initial use in metastatic colon cancer. The German company sells the medicine outside North America. Its U.S. partners Eli Lilly and Bristol-Myers market the drug in North America.
The survival benefit translated to a 23 percent lower risk of death for patients who got Erbitux, Merck said in an e-mailed statement. The German drugmaker said it looks forward to reviewing “emerging evidence” regarding how best to care for patients.
Germany’s Merck isn’t related to U.S. drugmaker Merck & Co.