Although some people have called it intriguing, a new “On The Horizon” drug, XL-184, is still very early in its testing. What makes LX184 intriguing is the just released results from a conference in Berlin.
In very early testing, 19 of 20 men in a phase I trial showed an improvement in their scans used to determine whether the cancer had spread to their bones. To the surprise of the investigators, in some cases, the bone scans could no longer detect any cancer in men who had already had scans that demonstrated the spread to the bones. Additionally, the men were able to stop taking the narcotics they were using to control the bone pain.
Before you become to excited, remember, these results are from a very small number of men and there was no control group in the trial design. Survival was not measured in this trial, so there is no way to know if it is possible for XL184 to prolong life or how long the improvement in bone scans will last.
However, “There’s really no precedent for another drug that does this,” said Dr. Matthew R. Smith, a prostate cancer specialist at the Massachusetts General Hospital. Additionally, one must remember that bone scans measure bone formation, not the presence of prostate cancer itself. So it cannot be ruled out that XL184 only stopped bone growth without killing the cancer. Pointing to the fact that there were signs that XL184