First human trials of prostate cancer drug shock doctors

Raw Story-Doctors at the Mayo Clinic in Minnesota announced on Saturday details surrounding the first human trials of a prostate cancer drug called Ipilimumab.

In their initial results, the doctors said, two men who were expected to die made dramatic recoveries after just a single dose.

One of the doctors said, according to a report in Saturday’s Independent, that the results are akin to the first time a human broke the sound barrier, calling it "one of the holy grails of prostate cancer research."

The UK paper reported:

Rodger Nelson and Fructuoso Solano-Revuelta were diagnosed with advanced prostate cancer and sought treatment at the Mayo Clinic.

They were told the disease had spread beyond the prostate. Mr Nelson’s cancer was encroaching on the abdomen and Mr Solano-Revuelta’s tumour was the size of a golf ball. Patients in such condition are told they may have only months to live, and are normally only offered palliative care. But after one infusion of the drug ipilimumab, a monoclonal antibody that stimulates the immune system, given with conventional hormone therapy, their tumours shrank enough to be surgically removed. Both men have since made a full recovery and returned to their businesses.

The pair were part of a trial involving 108 patients, half of whom received the experimental drug. The trial is ongoing but the improvement of the two patients was so dramatic and unexpected that they were removed from the study so they could undergo curative surgery.

Dr Kwon said yesterday: "Halfway through the trial we began seeing remarkable responses. Some patients had dramatic shrinkage of their tumours so practically all traces had disappeared. We had thought we might get some incremental delay in the progression of the cancer. It had not dawned on us that we might go from an inoperable tumour to an operable one. That just doesn’t happen."

The doctors said that once surgery began on their first subject, there was a question as to whether they had the right patient because the cancer was so hard to find. What was once an inoperable tumor shrank so dramatically that doctors were able to operate and remove the growth.

They did add one bit of caution: While the first human trials of Ipilimumab yielded wildly successful results, both men had undergone hormone therapy which can, in some cases, shrink the tumors by itself. Nevertheless, added Dr. Eugene Kwon, "These were patients for whom there was no hope. The course of their disease has been altered in a dramatic fashion. … [But] we have to complete our studies."

Ipilimumab, being developed by  Bristol-Myers Squibb and Medarex, "is a fully human antibody that binds to CTLA-4 (cytotoxic T lymphocyte-associated antigen 4), a molecule on T-cells that is believed to play a critical role in regulating natural immune responses," the drug makers said. "The absence or presence of CTLA-4 can augment or suppress the immune system’s T-cell response in fighting disease. Ipilimumab is designed to block the activity of CTLA-4, thereby sustaining an active immune response in its attack on cancer cells."

The Mayo Clinic plans to launch a larger trial of Ipilimumab this fall. Dr. Kwon’s trials are ongoing and will be the subject of a peer-reviewed study sometime in the future.

But for now, for all the sufferers of prostate cancer and their loved ones, there’s new hope.

— Stephen C. Webster