The crisis that has swept the biotech sector crashed into Medpace Holdings on Tuesday, sending shares of the drug-testing company down more than 13% in morning trading. Medpace which runs clinical trials of experimental medicines on behalf of drugmakers, revealed third-quarter results late Monday that implied weaker-than-expected demand from drugmakers. On an investor call Tuesday morning, Medpace CEO August Troendle said the company had seen higher-than-normal levels of cancellations in the third quarter, an issue that has dogged the company throughout the year.