ARTICLE SUMMARY:
One of the highlights of this year’s NANS meeting was Nevro’s presentation on results from its RCT for painful diabetic neuropathy.
There was a lot to unpack at the recent annual meeting of the North American Neuromodulation Society (NANS), the world’s largest gathering dedicated to advances in both the science and practice of neuromodulation. Held in Las Vegas in January, the meeting presented the latest research in spinal cord stimulation, deep brain stimulation, peripheral nerve stimulation, sacral nerve stimulation, and other neuromodulation targets, as well as nerve-targeted drug delivery and ablation, and minimally invasive spinal implant therapies.
At NANS, the over-arching theme of discussions about all of these modalities was the need for personalization. Clinicians need to have at hand a tool box, so they can administer to patients the therapy that works best for them, and still have options for their continued management in the future, should they become resistant to their previous treatment or develop new sources of pain.
It’s an exciting time for clinicians, who now have more to offer patients that have long suffered from chronic pain, and the opportunity to manage them into the future. And it’s a high-growth opportunity for the medtech industry, which is operating in a market segment that is extremely underpenetrated in terms of currently approved indications, and will continue to grow with the addition of new indications like painful diabetic neuropathy (PDN).
Nevro Corp., which is already advancing into the latter market, describes it as two to three million patients in the US. That estimate is based on 35-40 million people with diabetes, 4-5 million of them on medical management for PDN, and more than half of those not enjoying pain relief from pain drugs. One of the highlights of NANS was the presentation of three-month data on Nevro’s HF10 spinal cord stimulation system for the treatment of PDN.
Erika Petersen, MD, presented three-month results from a multicenter (18 centers) randomized, controlled clinical trial studying Nevro’s Senza-PDN high frequency (10 kHz) for the treatment of painful diabetic neuropathy. In the study, 216 patients were randomized, one to one, to medical management in the control arm, and medical management plus Senza-PDN in the treatment arm. “This is the largest RCT that has ever been done in the space of neuromodulation. We are excited to have invested in this and done this,” said David Caraway, MD, PhD, chief medical officer of Nevro.
The enrolled patients “look like the people who walk into your clinics, and they have been suffering horribly for long periods of time.”
Patients that met the enrollment criteria had painful diabetic neuropathy of the lower limbs and were refractory to two classes of medications, one of which had to be an anti-convulsant like pregabalin orgabapentin. The trial had generous inclusion criteria for these diabetes patients: a pain score of 5 or greater on the VAS (Visual Analog Scale), anHbA1c (measure of overall glycemic control) less than 10%, and a BMI (body mass index) up to 45 (diabetic patients with a BMI above 35 are considered to be morbidly obese).
Most patients in the study had lived with painful diabetic neuropathy for a little over seven years. Noted Caraway, the enrolled patients “look like the people who walk into your clinics, and they have been suffering horribly for long periods of time.”
The company had to screen 400 patients to enroll 216; many were outside the inclusion criteria, and many had not met the medical management criteria.
While safety and efficacy are the sine qua non of all therapies, for patients with diabetes it is even more crucial to demonstrate that surgical interventions are safe, since cardiovascular disease, peripheral vascular disease and other effects of diabetes make surgeries riskier for these patients. “We looked at this very carefully,” said Caraway, reporting that there were only two events in the SCS cohort; one patient had a wound dehiscence that required device explantation, and another had an infection that was resolved with debridement and antibiotics, and continues in the study. A 1.8% infection rate in the SCS cohort was especially low for a diabetes population, Caraway said.
In terms of efficacy at three months, 89% of patients in the Senza-PDN arm met the study’s primary endpoint of pain relief of 50% or better without increasing their neurological deficits, while, as to be expected in a refractory cohort, only 7% of patients in the medical management arm met the endpoint. Responders in the treatment arm experienced pain relief, on average, of 77%, while responders in the medical management cohort experienced a mere 5% reduction in pain.
Investigators also looked at sensory changes (degree of numbness) in these neuropathic patients, finding that 72% of patients in the Senza-PDN arm felt they had improved. Only 7% of patients on conventional medical management experienced improvement, 83% felt there had been no change, and 10% reported that they had worsened
Patients who’d received the Senza-PDN therapy also reported significantly larger improvements in their ability to fall asleep, and weren’t awakened by pain as often as the patients in the control group.
Although it’s an early signal of success, it’s promising. The study’s investigators will continue to follow the patients out to 24 months, after which Nevro aims to evaluate health economics and pain medication usage.
Although PDN is a new indication, these patients will be treated by the same pain clinicians that administer SCS now. However, referral patterns are more complicated, and whether the company develops an ability to capture patients from endocrinologists and primary care physicians or relies on a direct-to-patient campaign remains to be seen, said Grossman.
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