The idea of a cell therapy for Parkinson’s disease starts out simple: Symptoms of the progressive disease are largely driven by the deaths of dopamine-producing neurons found deep within the brain. With lower levels of the neurotransmitter come the characteristic tremors, rigidity and slow movements.
By replacing those lost nerve cells with new dopamine producers, researchers hope to renew the brain’s connection to the body’s muscles and improve a person’s overall motor function.
But in the brain, everything becomes more complicated. On top of the risk of immune system rejection that comes with any kind of living tissue transplant, it’s important to make sure the implanted cells function correctly and do not pick up any dangerous genetic mutations as they grow.
Now, a new company, Aspen Neuroscience, aims to tackle both obstacles at once.
First, the startup hopes to avoid any harmful immune reactions by using a patient’s own cells as a starting point. Then, Aspen plans to implement a rigorous quality control program employing whole genome sequencing and artificial intelligence to make sure the cells stay in line as they’re processed and readied for the procedure.
And to do it, the San Diego-based company is starting out with $6.5 million in seed money plus an impressive roster of names.
They are led by neurology researcher Howard Federoff, previously vice chancellor for health affairs and CEO of the University of California, Irvine health system as well as the executive dean of medicine at Georgetown University. He’s joined by Aspen co-founder and stem cell scientist Jeanne Loring, founding director and professor emeritus of the Center for Regenerative Medicine at the Scripps Research Institute.
Meanwhile, the seed round was led by Domain Associates and Axon Ventures with additional backing from Alexandria Venture Investments, Arch Venture Partners, OrbiMed and Section 32.
Aspen looks to combine its expertise in stem cell biology, genomics and neurology to offer the first autologous cell therapy for Parkinson’s disease—while others in the space have pursued allogeneic routes, or therapies derived from donors other than the patient.
The process starts with a culture of the patient’s skin cells, which are then genetically induced to become pluripotent stem cells—or cells capable of differentiating into any other cell type in the body. These are then chemically nudged further to transform into precursor versions of the dopamine-producing neurons, which are typically found in the midbrain and regions responsible for the movement of limbs.
“We can say without any equivocation that we can produce the population of cells necessary to transplant, and in a short enough period of time to have a potential beneficial impact on the evolution of the disease,” said Federoff, who has also served as chair of the NIH’s Recombinant DNA Advisory Committee and helped lead the U.S. Parkinson’s Disease Gene Therapy Study Group.
“We envisage that this will set back the clock on patients who have Parkinson’s, unlike any other therapy that we know of,” he told FierceMedTech in an interview.
The number of cells needed would be much smaller compared to other cell therapies and cancer treatments. The healthy human brain contains only about 200,000 dopamine-producing nerve cells, split between its two hemispheres, while patients with Parkinson’s disease have lost about 50% or more of those neurons.
Aspen aims to evaluate two doses: one that aims to replace about 60% to 65% of a person’s normal cell complement and another larger treatment, Federoff said.
Those smaller doses, as well as starting with a patient’s donor cells, help make the treatment safer to produce by requiring fewer steps. Each cycle of cell division and multiplication to increase their numbers carries the risk of introducing genetic mutations.
As the cells are grown, they are consistently evaluated with data-driven techniques pioneered by Loring’s laboratory. Using whole genome RNA sequencing, Aspen will match the cells up at every stage with a genetic barcode taken from each patient at the start. This will allow them to look for changes, duplications or deletions in the pluripotent stem cell genome.
“If the cells harbor mutations that are cancer drivers, we don't want to put those into people,” Loring said. “The only way is to check the sequencing before we transplant them.”
The cells used in the transplant procedure aren’t fully grown; as neuron progenitors, they mimic the development steps seen in the brain of a growing fetus after they’re placed in the body as they wire themselves up to other neural structures and begin to form new networks of their own.
“We anticipate that they will manufacture and release dopamine in a manner that is consistent with synaptic neurotransmission and the process of communicating from cell-to-cell,” said Federoff. “They will take up dopamine from synapses when it has done its business, bring it back into the cell, and prepare it for another synaptic release.”
“These are not just dopamine pumps, they’re real neurons,” added Loring. “They will genuinely replace the cells that have been lost in every way.”
Aspen plans to pursue two courses of therapy, for the two major types of Parkinson’s disease. Their lead candidate is for idiopathic, or sporadic Parkinson’s, while their second is a CRISPR-edited version of the therapy designed to address one of the disease’s most common genetic mutations, linked to about 5% of cases.
This would not only aim to restart dopamine production in this orphan indication, but also restore the damaged enzyme GBA, which is seen as an underlying cause. Federoff and Loring expect their sequencing-based quality check system will also help catch any off-target edits linked to the use of CRISPR-Cas9.
The company has yet to secure permission from the FDA to officially launch clinical trials, but the agency has signed off on Aspen’s plans to prepare a “trial-ready cohort” of Parkinson’s disease patients in the meantime. This would include the initial stages of recruitment and testing, including the selection of patients capable of having their skin cells made into pluripotent stem cells.
After it receives its go-ahead from the FDA, Aspen plans to hit the ground running, enrolling at least 176 participants in a phase 1/2 study that includes a randomized stage to determine clinical benefits.