New pain drugs in pipeline, but challenges to usage remain.

O ver the past two decades, pain control has become a front-burner issue among oncologists, but glaring problems in treating pain remain, a new survey shows. Barriers limiting pain control include patients' reluctance to report pain and to take opioids, coupled with physicians' reluctance to prescribe them, as well as increasing regulatory barriers, according to a study in the Nov. 14 online issue of the Journal of Clinical Oncology. " In the 1980s, pain control got a lot of attention, but in the past two decades, medical expertise has not progressed as well as treatment for cancer itself, " said Russell Portenoy, M.D., an author of the study and chairman of the department of pain medicine and palliative care at Beth Israel Medical Center in New York. " The drugs we have are not good enough, and we are not using the drugs we do have effectively, " according to Judy The JCO study emphasized that not all pain is equal. " Patients with multifocal pain, those who are medically frail, and patients with neuropathic pain are more difficult to treat, " said Portenoy. " Up to 50% of patients with cancer, and 75% with advanced disease, have pain not adequately controlled with opioids and other drugs, " said Paice. individual neurological mechanisms are involved in initiating and sustaining pain. His lab has identified the variant of a gene that makes an essential cofactor for the enzymes that synthesize amines and nitric oxide; this variant gene protects against developing pain by reducing synthesis of the cofactor in response to stress. Woolf is now working on making pain-susceptible individuals pain-resistant by mimicking the effect of the pain-protective gene variant with an enzyme inhibitor. Ultimately, he expects that no one type of analgesic will treat cancer pain but that control will be tailored to each patient. Inflammatory pain is hypersensitivity to a defined pathology, such as a tumor pressing on an organ or radiation damage of sensitive tissues. By contrast, neuro-pathic pain results from altered neural processing due to damage to the nervous system, such as a tumor invading a nerve. Neuropathy typically continues even when a tumor is removed. Cancer pain is often a complex mixture of these two types of pain. Pain also has a heritable component, so in the long term, defining who is at risk and identifying ways to pharmacologically reduce that risk will be important, Woolf said. …