A day after saying US regulators rejected their kidney cancer drug application and faulted their clinical results as “unintepretable,” top Aveo Pharmaceuticals Inc. executives Tuesday defended their clinical program and said they still believe their experimental drug is an effective treatment for kidney cancer.

In a conference call with industry analysts, executives of the Cambridge biotechnology company insisted they had been transparent throughout their dealings with regulators from the Food and Drug Administration. Even when FDA regulators had suggested another clinical study, Aveo executives argued, they did not say approval of tivozanib—the company’s drug to treat renal cell carcinoma—would hinge on that study.

“While it is not surprising” given the overwhelming FDA advisory panel recommendation against tivozanib last month, “we are still disappointed that the FDA did not approve our application,” Aveo chief executive Tuan Ha-Ngoc told the analysts. “Overall, we think this is a loss for patients who would have benefitted from tivozanib.

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Aveo chief medical officer William Slichenmyer said the company’s late-stage clinical trial with 517 patients demonstrated the drug slowed progression of the disease, the FDA’s primary “endpoint” criteria. But in a comparison with an existing drug, called Nexavar, tivozanib fell short of demonstrating that it improved patient survival rates better than the medicine already available.

Slichenmyer, however, said that was because Aveo permitted a “control arm” of the clinical trial—patients who were given Nexavar—to switch to tivozanib when their conditions worsened in what was called “a one-way crossover.”

“We believe the results were confused because some of the patients in the control arm received two drugs rather than one,” he said.

Aveo executives Tuesday reiterated their plans to move forward with the testing of tivozanib as a treatment for breast and colorectal cancers.