CytoTherapeutics Inc. is taking its encapsulation of therapeuticcell implants a step further by combining cell types to enhancefunction, a method that has resulted in U.S. patent No.5,182,111, issued to Brown University Research Foundation andlicensed exclusively to the company.

The technology could allow combining a growth-factorsecreting cell with a cell that produces a therapeutically usefulcompound to increase the capacity of the second cell to surviveand function, Michael Lysaght, vice president for research anddevelopment, told BioWorld.

CytoTherapeutics (NASDAQ:CTII) is pursuing treatments forParkinson's disease, severe, chronic pain and Type I insulin-dependent diabetes, using single cells encapsulated insemipermeable polymer membranes to shield the cells fromthe immune system, but allow small, beneficial molecules fromthe encapsulated cells to escape.

The encapsulated cells, in packets about the size of a matchstick, can be implanted where they are needed and laterretrieved, if necessary. The patent also coversmicroencapsulation, but the company has preferredmacroencapsulation because the implants can be removed andare more durable, Lysaght said.

The patented technology will be applied to research programsin Parkinson's, pain analgesia and diabetes, and may also beused in gene therapy with genetically engineered cells, Lysaghtsaid.

Parkinson's is a debilitating, ultimately fatal neurologicaldisease with no known cure. Patients develop tremor, rigidityand mild dementia. Symptoms occur when cells that producethe neurotransmitter dopamine die in a critical area of thebrain, the corpus striatum. Current therapy involves oral dosesof L-dopa, the precursor of dopamine. However, its efficiencywanes as the disease progresses.

CytoTherapeutics would initially use its technology to deliverdopamine directly to the brain with "NeuroCRIB" implants inlate-stage patients who receive little or no benefit from oraltherapy. Several hundred thousand patients in the U.S. areestimated to be in this category.

Parkinson's affects about 800,000 Americans overall, andapproximately one in 500 people over age 50 are expected todevelop the disease. Late-stage patients have a life expectancyof five to 10 years, during which they often require extensivecare and hospitalization.

CytoTherapeutics' newly patented technology may improve theviability and productivity of the dopamine-producing cells, saidSeth Rudnick, chief executive officer.

Type I diabetes, currently treated with injections of insulin,affects about 1.2 million Americans. The injections cannotrespond to constantly changing levels of blood sugar, however,so long-term insulin therapy is frequently associated with suchproblems as heart disease, kidney failure, blindness, stroke andsevere nerve damage.

As an alternative, CytoTherapeutics is developing "EndoCRIB"encapsulated islet cells from pigs, whose insulin has been usedfor 50 years in diabetics and is almost identical to humaninsulin.

In preclinical studies, the encapsulated cells produce insulinand respond to changes in blood sugar levels. However, moredata is needed to compare this method with current therapy,Lysaght said. Also, development may take longer because quitea bit of insulin must be produced to regulate cells' uptake ofblood sugar.

The pain program involves placing capsules of adrenalchromaffin cells in the spinal cord of the lower back, wherethey release enkephalins and catecholamines that interrupttransmission of pain signals to the brain. This "CereCRIB"technology is slated for human clinical trials in Europe this yearin cancer patients with severe, chronic pain, Lysaght said.

Although the first-generation products of the 4-year-oldcompany will not use multiple cells, the technology forcombining cells could expand the potential of encapsulationtherapy.

"The ability to include a growth factor-secreting cell with atherapeutic cell would enable us to use cells that have beendifficult to grow and sustain within the capsule," Rudnick said."Because the growth factor-secreting cell would regulate theamount and rate at which the therapeutic substances arereleased from the capsule, the scope of serious human diseasesthat could be treated with encapsulated cell therapy issignificantly broadened," Rudnick said.

Listed as inventors of the patent are Patrick Aebishcer, a co-founder of the company and professor of biomaterials at thedepartment of biomedicine at Brown University in Providence,R.I., and Shelley Winn, a staff scientist.

CytoTherapeutics' stock gained 25 cents a share on Monday,closing at $6.

-- Nancy Garcia Associate Editor

(c) 1997 American Health Consultants. All rights reserved.