Cala Health’s real-world study validates its wearable’s long-term efficacy

Cala Health recently published a post-market surveillance study that demonstrates the long-term efficacy of its wrist-based wearable for people with essential tremor, finding that the device reduced patients’ tremor power by 71%.

The Burlingame, California-based company was founded in 2014 as a Stanford University spinout. It makes a wrist-based wearable that uses electrical stimulation to temporarily relieve tremor symptoms.

The study, published last week in Tremor and Other Hyperkinetic Movements, showed that electrical stimulation therapy delivered by Cala’s device, called Cala Trio, significantly reduces patients’ tremor with no loss of effect over time. 

Cala Trio works by delivering an electronic signal across the skin that goes from the fingers through the spinal cord up to the brain, Dr. Dhira Khosla, Cala’s medical director, said in an interview. 

The device’s band contains an electrical stimulator as well as electrodes that sit over two nerves in the wrist — the median and radial nerves. These electrodes allow the device to measure the frequency of a patient’s tremor. Cala’s device takes that frequency and calculates a stimulation pattern it can provide to interfere with the tremor network in the brain, according to Dr. Khosla.

“Once that tremor network is interrupted by the stimulation from the device, the patient can get tremor reduction and tremor relief,” she said. “This tremor relief lasts about 90 minutes on average, which for some patients is enough to go have lunch with their families or give a presentation at work or something else that’s meaningful or important.”

The recently published study that validated Cala Trio’s efficacy involved 321 patients who had  completed at least 90 days of therapy using the device from August 2019 through June 2021. It contains the largest patient set and the longest usage period (up to two years) of any evaluation of a noninvasive essential tremor treatment, according to the company.

The study not only found that the device reduced patients’ tremor power by 71%— it also showed that more than half of patients experienced reduction of tremor power by at least 50%. No loss of effect was observed among patients who used the device for longer than a year, and there was no significant reduction in improvement between the first three months and beyond the one-year mark, Dr. Khosla pointed out. 

The result is especially notable compared with how people respond to drugs.

“This is unlike medications. People’s brains actually get used to medication and they need higher doses to maintain the same tremor reduction and control,” she said. “In the case of the Cala device, we looked at the first 90 days of use versus the next 90 days and beyond, we didn’t find evidence of habituation. Patients were really able to use the device and get the same level of tremor reduction for a longer period of time.”

Most patients involved in the study reported improvement in daily activities. Nearly three-quarters said the device improved their ability to eat, 65% reported improvement with drinking, and 64% said it helped with writing.

Study participants’ feedback showed that they enjoyed using the device to treat their essential tremor because it is noninvasive and nonpharmacological. They liked that they had this option instead of undergoing brain surgery and taking on the risk of surgical infection, Dr. Khosla said.

Users also liked that the device was a non-drug treatment, which meant they didn’t have to deal with unwanted side effects or add another medication to their routine. Dr. Khosla pointed out that even though nearly 10 million of the people in the U.S. suffer from essential tremor, there aren’t medications made specifically to treat the condition. She said the medications neurologists use to treat essential tremor are originally made for other reasons, such as reducing blood pressure and treating seizures. 

Among the patients who were on tremor medication prior to using Cala’s device, 24% reduced their tremor medication and 14% stopped using these drugs. 

Cala Trio received de novo clearance from the Food and Drug Administration in 2018, later earning 510(k) clearance for the temporary relief of hand tremors in adults with essential tremor in October 2021. 

Patients obtain the device via a prescription written by their primary care physician or neurologist — more than 1,000 patients across the U.S. currently use the device to treat essential tremor. Cala has coverage agreements for its device with the Department of Veterans Affairs and Medicare, according to Doug Biehn, Cala’s chief commercial officer. He said the company is working to ensure more coverage among commercial payers.

Cala is among a small number of companies making electrical stimulation devices to treat tremors, including Allevion Therapeutics and Encora TherapeuticsResearchers say more studies are required to determine whether wearable devices can create longer-lasting relief from a single session, beyond reducing tremors for and hour or two at a time. They also suggest that further research is needed to solidify wearables as a standalone treatment for essential tremor patients.

Photo: aldomurillo, Getty Images