New Pain Drug Shows Promise in IC Patients

The nerve growth factor inhibitor tanezumab is showing great promise for knocking down IC pain. The ICA’s own Medical Advisory Board member, Robert Evans, MD, presented the results of the first proof-of-concept study in IC last week at the 20th Annual Clinical Meeting of the American Academy of Pain Management meeting in Phoenix, Arizona.

The new monoclonal antibody drug from Pfizer is given intravenously and is also being studied in other pain conditions. Nevertheless, IC will be one of the conditions it seeks FDA approval for. That’s great news for IC patients, since that may make insurance coverage easier and will certainly increase IC awareness.

Patients in the study included both men and women with moderate to severe IC. After keeping a symptom diary and scoring their bladder pain for seven days, half got an infusion of the drug (adjusted for weight), and half got a placebo. They continued keeping their symptom and pain diaries and had doctor visits every 2 weeks for 10 weeks and then again 16 weeks later. In those who got the drug, average pain scores went from about 6.5 to a little more than 4 six weeks later, when peak effect was expected, rising slowly after that to about 5 16 weeks later. Those who got placebo had scores start at about 6, dropping to 5 at 6 weeks and to about 4 16 weeks later.

Although that doesn’t seem like much, Dr. Evans said in his patients, “it was huge. . . . They really felt significantly better.”

The study’s aim, he pointed out, wasn’t to thoroughly evaluate the results. Many more IC patients are needed for that. This phase 2a trial was a proof-of-concept study, intended to check safety and feasibility. Patients underwent careful neurologic examinations at every visit to check for side effects, which proved to be minimal. Headache and tingling (in the feet, for example) were the most common.

The next step is to try different doses to see what dose and timing is optimal, and we may be hearing more about that at the American Urological Association meeting next May.

Because the drug is not aimed at pain in the bladder alone but at pain that has become chronic in the central nervous system, this drug may prove helpful for many more types of chronic pain, which doesn’t respond well to most available drugs. In fact, studies are already under way in men with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS).

Posted October 15, 2009