A New Hope

An imaging agent available first at Mayo Clinic detects recurrent prostate cancer earlier

By Mayo Clinic Staff

When Mike Hawker came to Mayo Clinic, he had about a month to live. Today, a new imaging agent keeps his cancer in check so he can enjoy life as an Alaskan legislator.

Huddled into a ball on his airplane seat, watching out the window as the Alaskan landscape slowly receded, Michael Hawker thought it was the last time he'd see the Land of the Midnight Sun.

Prostate cancer had so riddled his body — spreading to his spine, femur, lymph nodes, pelvis, bladder and eye sockets — that his life expectancy was less than a month. He was flying to Mayo Clinic in Rochester, Minn., looking for a miracle.

"I had come to the point where I saw my death and accepted my mortality," the Alaska state legislator says.

His wife, Carol, hadn't. Fighting to give her husband one last chance, she called Mayo Clinic to find a physician with experience in widely metastatic neuroendocrine prostate cancer. When she reached the urology appointment desk, Eugene D. Kwon, M.D., research co-director for the Department of Urology and the Cancer Immunology and Immunotherapy Program, happened to be walking by and overheard his name and a bit of the conversation.

Dr. Kwon asked to speak to the caller.

"That is remarkable in itself," Michael says. "I understand doctors just don't take cold calls."

Within days of that conversation, Michael and Carol boarded a plane headed to Rochester, Minn.

The most miserable week of my life

Despite four months of chemotherapy in Alaska, Michael's cancer grew unchecked. "My body was completely debilitated, and my wife had to do everything for me," he says. "I hardly remember the plane ride to Minnesota."

Upon Michael's arrival at Mayo Clinic on Dec. 1, 2010, Dr. Kwon ordered a back-to-back series of bone, pelvic, bladder and prostate biopsies and started Michael on hormone therapy to fight the cancer. "It was quite literally the most painful and worst week of my life," he says.

By Dec. 8, Michael's prostate-specific antigen (PSA) levels had dropped from 36 to six.

"We just couldn't believe it," Michael says. "This was the first time in six months we received news other than 'you're going to die.' "

And so began Michael's long-term relationship with Dr. Kwon and Mayo Clinic. Within a few months of receiving hormone treatment, Michael's PSAs were nearly undetectable and stayed that way until fall 2012.

Keeping cancer at bay

Dr. Kwon views Michael's cancer as a major offender on probation. To keep his cancer in line, Michael has his PSA levels checked regularly with doctors in Alaska, and every six months he returns to Mayo Clinic for a thorough once-over.

In September 2012, Michael's PSA level increased from 0.1 to 0.2 nanograms per milliliter (ng/mL). For most men, such an infinitesimal increase wouldn't cause concern. But for Michael, who had cancer throughout his body, the slightest increment is a four-alarm call to action.

As soon as his numbers started rising, Michael headed back to Mayo to pinpoint where the cancer was hiding through a powerful new diagnostic tool: Choline C-11 Injection, which can help locate cancer when PSA levels are at least half of what traditional imaging techniques can detect.

Detecting and defeating recurrent prostate cancer

This new imaging technique uses a radioactive form of the vitamin choline, which cancer cells readily absorb. Clinicians inject a small amount of the agent into a patient's vein and then use a positron emission tomography (PET) scanner and computer to see where the agent collects. The result is a detailed map of a person's cancer.

The Food and Drug Administration (FDA) approved Mayo Clinic as the first institution in the U.S. that can manufacture and administer Choline C-11 Injection. The technical name for the compound is 11C choline. The 11C denotes that a carbon atom has been made radioactive and has a half-life of 20 minutes, which means for every 20 ticks of the clock the agent loses 50 percent of its efficacy.

Its short life span means 11C choline needs to be made for each patient and administered within minutes of its creation. Michael's Choline C-11 Injection identified four spots of prostate cancer activity. After clinical confirmation of the imaging results, doctors quickly treated him with radiation therapy, and today Michael's cancer is once again in check.

A game changer

Until this technology became available, determining how to treat recurrent prostate cancer could be a guessing game, as physicians couldn't tell where the cancer was. Even if a traditional PET scan revealed a mass that early, it was very difficult to tell what the mass might be — scar tissue? Arthritis? An inflammation? Cancer? Choline C-11 Injections help change that dynamic, so doctors can react more quickly and craft more-targeted therapies.

Back in Alaska, Michael is healthy and feeling on top of the world. "I have been granted a second chance at life by the people who work at Mayo Clinic and the tools and technology they have. I recognize this and am grateful for it. Every day burns a little bit brighter. I only have so many days left on this planet, and I truly want to leave a legacy of something good. I cannot describe how happy I am to be alive."

The right thing to do

Pharmaceutical companies have known of 11C choline's imaging power for some time, but none have spent precious development resources pursuing it. From a profit point of view, it has three strikes against it: It's not patentable, it's only good for a short amount of time (20-minute half-life), and it's virtually impossible to distribute in mass quantities.

But Mayo Clinic's Eugene D. Kwon, M.D., Val Lowe, M.D., and Joseph C. Hung, Ph.D., knew it had potential to impact the care of prostate cancer patients. So, with the help of colleagues R. Jeffrey Karnes, M.D., and Christopher R. Mitchell, M.D., they pursued, on their own time, Mayo Clinic's first new drug application with the Food and Drug Administration (FDA).

They didn't have $4 billion, which Forbes Magazine reports is the average amount a pharmaceutical company spends for every drug approved. And they didn't want to wait patiently the typical 10-plus years it takes to put a drug through the usual approval process.

"We pursued this because it's the right thing to do," says Dr. Lowe, a specialist in nuclear medicine and PET imaging at Mayo Clinic. "We believe it will save more lives."

So, armed with years of research and published literature, the Mayo team met with the FDA to determine if Choline C-11 Injection qualified for a new drug application. The FDA gave the green light to the researchers and granted a priority review for the application. Within nine months of the researchers' application submission, the FDA approved Mayo Clinic as the first institution in the U.S. to manufacture and administer Choline C-11 Injection to help identify recurrent prostate cancer.

"The evidence is compelling," says Dr. Hung, director of the Mayo Clinic PET Radiochemistry Facility. "We were hoping the FDA would agree. And they did."

Mayo physicians want to use Choline C-11 Injection to investigate where prostate cancer manifests in the body and determine what treatments work best for which forms of prostate cancer. The team is also specifically interested in developing the next generation of other radioisotopes to pinpoint all types of cancer and other diseases, like Alzheimer's.