Some critics have suggested that clinical trials be limited to only the sarcoma subtypes that show the greatest initial response. But Dr. Tap said he wouldn’t want to focus on one or two subtypes while other patients who might have responded go untested.
"A phase 2 study showed broad activity across sarcoma subtypes."
Some recent drug studies have looked at progression-free survival, i.e., how long a patient lives without the sarcoma returning or advancing. The TH-302 trial looks at whether patients live longer, Dr. Tap said.
“In sarcoma, in more than 30 years, we haven't had a new drug that we believe affects overall survival," he said, except those used for gastrointestinal stromal tumors.
Some people think TH-302 may fail because palifosfamide did, Beckert said. Both are chemical cousins of ifosfamide, but less toxic. Ifosfamide, an older drug, is sometimes paired with doxorubicin for chemotherapy. The palifosfamide trial combined it with doxorubicin in one arm vs. doxorubicin alone – similar to the TH-302 trial.
"They're different drugs,” Dr. Tap said. “It's like comparing apples and oranges. The key is the delivery method."
Unlike palifosfamide, TH-302 activates in tissue with low oxygen, and those conditions often exist in the center of a sarcoma, he said. This differs from other drugs that attack the edges of tumors, which have more blood vessels and thus, more oxygen.
For more information on the Sarcoma Alliance, go to http://sarcomaalliance.org
Read the full story at http://www.prweb.com/releases/2013/6/prweb10866921.htm.
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