Local parents find hope in drug trial
Boys with muscular dystrophy see results through national study
Thursday, December 21, 2006
Short stuff: Health
Tne day last spring, as her 8-year-old son Timothy raced around the playground during her older son’s baseball game, an acquaintance said something to Ellen Wagner that made her pause.
Something seemed different about Tim. He’d never seen him run like that and was curious to know what had changed.
To Wagner, of McHenry, it was proof that Tim, who has Duchenne muscular dystrophy or DMD, was benefiting from a cutting-edge treatment he was taking as part of the second phase of a national study.
Recently, Wagner’s observations about her son’s improvements were backed up with the release of preliminary data showing that the treatment, called PTC124, increased many of the 26 participants’ dystrophin levels. A protein, dystrophin is needed to keep muscles strong and when it is not produced, as happens in muscular dystrophy, muscles break down and eventually fail.
"This changes the whole picture," Wagner says. "You have in your mind that this is a progressive, terminal disease and maybe it’s not going to be that anymore. Maybe we’ll never get to the point where he needs a wheelchair ... Maybe he’ll go to college. It’s still scary because we don’t want to pin all of our hopes on it, but wouldn’t it be exciting if he didn’t get any worse?"
Twenty-five boys like Tim, whose form of DMD is caused by a nonsense mutation, took PTC124 three times a day by mouth for about a month. Before starting and after finishing the treatment, the boys underwent muscle biopsies at testing sites in Cincinnati, Philadelphia and Salt Lake City, where doctors looked for dystrophin.
Developed by New Jersey-based PTC Therapeutics, the drug is geared toward genetic diseases caused by nonsense mutations, which account for between 13 and 15 percent of the 20,000 DMD cases reported worldwide each year.
According to Valerie Cwik, a neurologist and medical director of the Tucson-based Muscular Dystrophy Association, nonsense mutations occur when just a single point on the gene is changed. All genes carry instructions that account for the way the body functions and when mutations occur, those functions are changed or disrupted.
"A point mutation is a sort of stop sign," Cwik says. "When the genetic translation machinery gets to that point in the instructions, the protein productions stops. The fragment of protein is not really functional and gets chewed up by the body so that the boys are left with no dystrophin in the muscles."
PTC124 tells the cells to read through the stop sign and continue following the instructions, which results in production of full-length proteins.
"These are exciting results," Cwik says. "This is the first time a drug of any sort has done this. One of the most important factors here is that it provides hope that different therapies are on the horizon to really make major inroads at treating this disease."
At present, the results of phase two are being reviewed by regulatory authorities with the intent of initiating the study’s third phase this year.
For the families of children with DMD, many of whom belong to and heard about the trial though the national advocacy and support group Parents Project Muscular Dystrophy (PPMD), the next step can’t come soon enough.
"Waiting is difficult, but we’ve sort of trained ourselves to go one day at a time—we have no choice but to be patient," says Carolyn Monson of Arlington Heights, whose 13-year-old son Grant was in the trial. "We’re elated, so excited and encouraged by the preliminary data. And all of us are hoping that this happens sooner than later."
Because of the degenerative nature of muscular distrophy, each passing day means further deterioration. Patients typically begin using wheelchairs in their teens and oftentimes need respiratory support at night. As they age, their respiratory systems continue to weaken and patients typically survive into their mid-20s.
"When you have a child that has such a devastating disorder, you want to feel like you’re proactive and tend to kind of do whatever you can do to make him better," says Sandy Mabus of Mount Prospect, whose 10-year-old son Jacob has DMD.
For the many challenges the participants already face, they were not the least bit hesitant to participate in the drug trial, their mothers’ say.
"Jacob knows that there are young men in wheel chairs that are worse off than him and so he looks at himself as having it pretty good," says Mabus, who heads the Chicago’s PPMD support group. "When he said he wanted to do the trial, I told him that what he is doing is something magnificent—that he’s not just helping himself, but he could be helping a lot of people. I think it’s good for us to realize these boys are doing something heroic, because if this drug becomes viable, they really are heroes."
Robin Huiras is a writer living in Evergreen Park.