The investigational cellular product (Spheramine), which is being evaluated in a new clinical study called STEPS1, consists of RPE cells attached to microcarriers. RPE cells produce levodopa, the precursor of dopamine. Dopamine is a neurotransmitter produced by nerve cells in the brain that progressively declines as the disease progresses. The RPE cells, which are normally found in the back of the eye, are cultured under standardized conditions and attached to the microscopic beads prior to implantation. The microcarriers are necessary for the cells to survive in the brain. The implanted cells serve as a new potential source of levodopa to enhance dopamine production where it is most needed.
An earlier pilot clinical study at Emory University implanted six advanced Parkinson's patients with cells on one side of the brain. These six patients experienced sustained improvements in motor function, averaging 41 percent at 24 months following treatment. In addition, there have been no safety concerns more than two years post treatment, according to neurosurgeon Dr. Roy A.E. Bakay, now at Rush and member of the Chicago Institute of Neurosurgery and Neuroresearch (CINN) medical group, who performed the surgical implantation for the study.
Along with Bakay, Rush neurologist Dr. Leonard Verhagen is the principal investigator for the Chicago site for this new Phase IIb, blinded STEPS study. Recruitment for the 68 patients for the study has recently begun. Each patient will be followed for approximately two years.
While the pilot study evaluated treatment on just one side of the brain, the STEPS research study will implant cells bilaterally, as Parkinson's affects both sides of the brain. Half of participants will receive Spheramine and half will receive placebo, or imitation surgery. For the participants receiving treatment, neurosurgeons will implant approximately 325,000 cells on each side of the brain (a total of 650,000 RPE cells) during MRI-guided injections. The cells will be implanted in the striatum, the part of the brain that controls movement.
"This research is promising because it may ultimately provide Parkinson's patients with a new method to achieve continuous control of motor function," said Verhagen. "Current medical therapies provide relief from symptoms for short periods of time, but then the effect of one dose of medication wears off, requiring patients to take another pill and wait until their symptoms subside again." In the pilot clinical study, which tested the preliminary safety and efficacy of the treatment, the six patients knew that they were receiving the RPE cells.
The current STEPS study is an expanded, placebo-controlled research study that involves a number of measures to ensure the integrity of results and that bias or the power of suggestion does not affect the results. Patients from Chicago will have surgery at another site, then return to Chicago for follow-up, to prevent accidental communications between the neurosurgery staff and neurologist Verhagen who will assess the patients over the two-year period. This will ensure that neither the physician nor the patient knows if the patient received the cell therapy treatment or a placebo.
Rush neurosurgeon Bakay will operate on patients recruited from Emory University, Atlanta or Baylor University School of Medicine, Houston, who then return to their home city for follow-up.
Parkinson's disease (PD) is a disorder of the central nervous system that affects between one and one-and-a-half million Americans. Because it is not contagious and does not have to be reported by physicians, the incidence of the disease is often underestimated. PD may appear at any age, but it is uncommon in people younger than 30, and the risk of developing it increases with age. It occurs in all parts of the world, and men are affected slightly more often than women.
When the study is completed and if the results show a benefit, research participants who did not have Spheramine implanted will be offered the therapy. Patients who are interested in learning more about the STEPS clinical research study can call 1-866-STEPS03 (1-866-783-7703).
Rush University Medical Center is an academic medical center that encompasses the 824-bed Presbyterian-St. Luke's Hospital (including Rush Children's Hospital), the 110-bed Johnston R. Bowman Health Center and Rush University. Rush University, with more than 1,270 students, is home to one of the first medical schools in the Midwest, one of the nation's top-ranked nursing colleges, as well as graduate programs in allied health and the basic sciences. Rush is noted for bringing together clinical care and research to address major health problems, including arthritis and orthopedic disorders, cancer, heart disease, mental illness neurological disorders and diseases associated with aging.
The Chicago Institute of Neurosurgery and Neuroresearch is one of the nation's leading organizations for the diagnosis, treatment and rehabilitation of people with brain and spine disorders. Originally founded in 1987, CINN is the Midwest's largest team of neurosurgeons known for their pioneering treatments in minimally invasive techniques. Through a network of seven hospitals spanning two states, CINN treats more patients with brain tumors and spine disorders than any other physician group in Illinois.
The STEPS research study is sponsored by Titan Pharmaceuticals, the developer of Spheramine, and Schering AG, Germany.