BioWorld International Correspondent

BORNHEIM, Germany ImClone Systems Inc.’s U.S. setback on Erbitux won’t affect development of the drug in Europe, where the German pharmaceutical company Merck KGaA said trials remain on schedule.

ImClone in December said the FDA would not accept its biologics license application for Erbitux (cetuximab or C225) in irinotecan-refractory colorectal cancer. The drug candidate is a radiolabeled antibody.

Darmstadt-based Merck has a license to the rights for the drug outside North America, except for Japan. In Japan the company shares development and commercialization rights with ImClone and Bristol-Myers Squibb Co., which has rights in the U.S.

“As public discussion on ImClone and the refusal to file’ letter from the FDA starts to affect the product, we see the need to clearly demonstrate that we believe in this product, and that our preparations for the European approval are on schedule,” Merck spokesman Hartmut Vennen told BioWorld Today. “Our own studies demonstrate the value of this product. That’s what we want to point out for our territory.”

Merck’s own multicenter trials in Europe aim at approval of C225 for treatment of patients who are refractory to the standard treatments of cisplatin in head and neck cancer and irinotecan in colorectal cancer.

In Merck’s pivotal Phase II/III trial in head and neck cancer, researchers are testing C225 when added to the cancer drugs cisplatin or carboplatin in patients who have shown cancer progression. Inclusion of patients into the trial requires that tumor progression is documented by computerized tomography (CT) or magnetic resonance imaging (MRI) before inclusion, the company said, adding that the trial is undergoing final evaluation.

Supportive data concerning the single-agent activity of C225 in patients with refractory head and neck cancer are being generated in an ongoing trial, Merck said.

To support the filing for colorectal cancer, Merck began enrolling patients in a large, randomized multicenter trial in patients with irinotecan-refractory colorectal cancer in July 2001, the company said. Inclusion criteria for this trial included collection and review of all pre-study CTs or MRIs. About 100 out of 225 patients have been recruited so far, Vennen said. In addition, supporting Phase I/II and pharmacokinetic studies are ongoing, Merck said.

“Our initial plan to file with the European authorities in the third quarter this year is unchanged,” Vennen said, adding that market launch might be expected in the third quarter of 2003.

However, the FDA’s action is expected to delay approval in the U.S. and thus in Switzerland, too, Merck said. This is due to the fact that a Swiss filing was to be based on ImClone’s U.S. application, Merck said.

Expected European sales are “really difficult to predict,” because it is one of the first products of this class of biologic cancer treatments,” Vennen said. “We would not speculate on this, [but] analysts’ estimations [in the range of US$700 million to US$1.4 billion] seem to be realistic.”