Clinically significant tumor shrinkage occurred in 12 percent of the patients.

Furthermore, the longer survival without tumor shrinkage of change in progression is surprising.

Historically, fewer than 5 percent of drugs studied in Phase 1 trials have produced measurable tumor shrinkage.

And in the company study, only 10 percent of patients in each group had any sign of tumor shrinkage.

But the patients who received the combination did not live noticeably longer than those who got Erbitux alone, despite the greater rate of tumor shrinkage.

Only 17 percent of patients receiving cisplatin alone experienced tumor shrinkage.

In other words, the agency asked, could Erbitux have achieved the same tumor shrinkage by itself?

The company reported tumor shrinkage in 22.5 percent of the patients, who were given both Erbitux and irinotecan.

There is some debate about the relevance of tumor shrinkage, since sorafenib might help patients just by keeping tumors from growing.

During the 19th century, tumor shrinkage after a high fever due to infection had been reported in a small number of cases.