By Peter Loftus
CHICAGO (MarketWatch) -- The drug Erbitux produced a modest improvement in a measure of survival in colorectal cancer patients when used as a first-line treatment with chemotherapy, according to a new study.
Erbitux is co-marketed in North America by ImClone Systems Inc. and Bristol-Myers Squibb Co. /zigman2/quotes/202559280/composite BMY +0.13% , and outside North America by Merck KGaA (MRK.XE) of Germany. Results of the Merck KGaA-sponsored study were released early Monday in conjunction with the annual meeting of the American Society of Clinical Oncology in Chicago.
Erbitux already is approved to treat people with advanced colorectal cancer, in combination with Pfizer Inc.'s /zigman2/quotes/202877789/composite PFE +0.74% Camptosar after Camptosar has failed to halt the disease. Or, it can be used as a single agent in patients who can't tolerate Camptosar.
The latest study tested Erbitux in a different setting: in previously untreated patients, and with a chemotherapy regimen known Folfiri, which is a combination of Camptosar, 5-fluorouracil and leucovorin. It was the first study to test Erbitux plus Folfiri as a first-line therapy for advance colorectal cancer.
About 1,200 patients received either the combination of Erbitux and Folfiri, or only Folfiri. Progression-free survival, which measures time until patient death or tumor growth, was 8.9 months in the Erbitux group and 8 months in the Folfiri-only group. Side effects were generally similar between the groups, although a higher rate of people in the Erbitux group had significant diarrhea and skin reactions.
ImClone had announced in January the so-called "Crystal" study met its primary goal of increasing median duration of progression-free survival, though it saved the details for this week. ImClone shares had risen 5% that day on hopes that the study would lead to wider use of Erbitux and potentially help it muscle in on turf now held by Avastin, Genentech Inc.'s /zigman2/quotes/226092395/composite DNA +0.51% first-line colorectal cancer treatment.
However, in recent weeks, investor enthusiasm for the Crystal study has been dampened. Details of the study trickled out, including the relatively small progression-free survival benefit of less than one month. In comparison, a previous study of Avastin in combination with a chemotherapy regimen improved progression-free survival to 10.6 months versus 6.2 months in the chemotherapy-only group. Some analysts have suggested the modest improvement in the new Erbitux study might limit expansion of its use as a first-line treatment.
ImClone shares have fallen about 9% since May 9, closing Friday at $41.25.
The stock is still up more than 50% year-to-date, however, helped by news in March that a rival drug, Amgen Inc.'s /zigman2/quotes/209157011/composite AMGN +0.12% Vectibix, was associated with decreased survival when used as a first-line colorectal cancer treatment with Avastin in a study. That study diminished the competitive threat posed to Erbitux by Vectibix, which is currently approved as a second-line treatment.
Investor reaction notwithstanding, researchers view the improved progression-free survival in the latest Erbitux study as significant. "These findings suggest we have a new option for the initial treatment of metastatic colorectal cancer," Eric Van Cutsem, a medical professor in Belgium who led the study, said in an ASCO press release.
A separate study of Erbitux presented at ASCO showed that it extended the lives of people with head and neck cancer, when used in combination with chemotherapy. But a third study presented here showed that it failed to significantly improve survival in pancreatic cancer.
The drug went on sale in 2004 and generated about $652 million in sales for its primary marketer, Bristol-Myers, last year, up 58% from the year before. ImClone receives royalties on Erbitux sales.