The Long and Winding Cancer Clinical Trial Road

Kidney cancer drugs battling it out in clinical trials

(RxWiki News) The clinical trial process is a long and winding road that has lots of twists and turns. Clinical trials comparing two kidney cancer drugs illustrate this beautifully.

In a Phase II trial, a drug known as tivozanib appeared to work better than the standard of care medication called Nexavar (sorafenib) in key areas.

Tivozanib was shown to give patients with advanced renal cell carcinoma (kidney cancer) more time before the disease got worse. This is called progression-free survival.

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The drug tivozanib, which is made by Aveo Pharmaceuticals, had other advantages which were presented at the 2012 American Society of Clinical Oncology meeting in June.

In the trial, a total of 517 patients were assigned to one of the drugs. Some took 1.5 mg of tivozanib (T) once a day for 3 weeks followed by one week off.

The other group took 400 mg of sorafenib (S) twice a day for four weeks. Sorafenib is a Bayer/Onyx medication.

Participants had either not received any treatment prior to the trial or had undergone one round of chemotherapy.

Researchers were looking to see the difference in progression-free survival (PFS) between the two drugs. Here’s what they found:

  • PFS was 11.9 months for those on T and 9.1 months for those taking S.
  • For those who had received no previous treatment, the disease didn’t get worse for 12.7 months on T vs. 9.1 months for those on S.
  • Overall response rate (ORR) was 33 percent for T patients and 23 percent for S patients.
  • The most serious side effects for people taking tivozanib was high blood pressure, and hand-foot syndrome (viral infection that causes sores on the mouth, hands and feet) for those taking sorafenib.

The most important measure – lifespan – was not complete at the time the trial ended. But the authors concluded, “Tivozanib demonstrated significant improvement in PFS and ORR compared with sorafenib as initial targeted treatment for advanced RCC.”

Now for the twist.

In the current Phase III trial investigating these drugs, patients taking S are living longer than those taking T. After one year, 77 percent of patients taking T are alive, compared with 81 percent taking S.

Aveo has explained these findings by saying that the survival data is skewed, because those patients whose disease got worse were switched to their drug – tivozanib.

So the twists and turns of clinical trials continue. More to come.

All research is considered preliminary before it’s published in a peer-reviewed journal.

A number of the researchers involved with this study disclosed financial ties with a number of pharmaceutical companies, including AVEO, Bayer, GlaxoSmithKline, Pfizer and Roche, among others.

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Review Date: 
August 30, 2012