A universal antivenom being tested at Duke could change snake bite treatment worldwide

·7 min read

Duke Health is a trial site for a drug that could be the first universal antivenom to treat any kind of snake bite — including North Carolina’s ubiquitous copperhead.

Currently, an antivenom specific to the type of snake bite is required to treat serious bites, and the antivenom is administered intravenously in hospitals. The universal antivenom being tested now is in pill form. If successful, the pill could become distributed across the world, possibly breaking down many barriers to healthcare and reducing the cost of snake bite treatment.

“The cornerstone of therapy for snake bites is antivenom treatments, and it’s been around for about 120 years,” said Dr. Charles Gerardo, an emergency medicine specialist at Duke Health. “It’s gotten better over the years, and it’s now safe and effective. But there are some gaps and limitations, and this novel agent is directed at filling some of those gaps.”

Ophirex, the drug manufacturer, is a public benefit corporation focused on developing affordable, accessible, oral treatment for snake bites.

It’s estimated that 2.7 million people get venomous snake bites per year, according to the World Health Organization. Between 81,000 and 138,000 die each year, and about three times as many more are left with permanent disabilities.

Many venomous bites occur in rural or remote areas with limited access to healthcare providers that carry antivenoms (sometimes referred to as antivenins), according to Duke Health. Time is a big factor in treating venomous snake bites, as bites that aren’t treated quickly can lead to loss of limbs or even death.

The News & Observer spoke with Gerardo, who is leading Duke’s participation in the universal antivenom research; and Malcolm Chandler, a participant who joined the antivenom study after being bitten by a copperhead in his Durham backyard in May.

Universal antivenom pill at Duke Health

Duke Health was the first site to enroll in testing the oral novel therapy for venomous snake bites. In total, six sites in the United States and six in India will participate in the study.

The United States has two families of venomous snakes — pit vipers (which include copperheads) and coral snakes — with a different antivenom for each family, Gerardo said. These antivenoms are antibodies to snake venom components that were produced in large mammals, like horses or sheep.

It’s nearly impossible in the United States to give the wrong antivenom for a pit viper or coral snake bite, as the bites look very different, Gerardo said. Both of those antivenoms are only to be administered intravenously, or within a vein.

The universal antivenom, if successful, will simplify treatment.

“One of the things that makes this treatment novel is that you can take it orally, which makes for potential ease of administration and ease of training to administer it. Though we’re not looking at this now, future studies can focus on getting the drug before you get to the hospital,” Gerardo said.

American researchers are looking at how this pill works with bites from pit vipers and coral snakes, while Indian researchers are studying bites from monocled cobras, Russell’s vipers and other venomous snakes, Gerardo said.

A copperhead snake in the grass.
A copperhead snake in the grass.

How the antivenom drug study works

The drug is currently being administered in conjunction with intravenous treatments. After determining the success of this study, the drug could be tested for use ahead of intravenous treatments or possibly in place of them entirely.

“With this current study, people who choose to enroll are receiving standard of care no matter what. So if you get a snake bite, you’re getting antivenom and hospitalization for treatment, and this medication is an addition to that,” Gerardo said. “The study drug, in addition to standard of care, is either the active drug or a placebo. Then we compare the two arms of the study.”

The study is double-blinded, and Gerardo said he does not yet know who has received the active drug — called varespladib-methy — and who has received the placebo.

Durham’s Chandler was the seventh participant in the study, which requires more than 100 participants to analyze findings.

How can universal antivenom lower antivenom costs?

“It’ll be a pretty long time before we know if the pill alone can be the treatment, but there are a number of ways the pill can work to reduce costs,” Gerardo said.

The universal antivenom may:

  • Lessen the amount of intravenous antivenom required to treat the venomous bite in the first place.

  • Reduce the need for painkillers, such as expensive opioids.

  • Shorten hospital stays, reducing non-antivenom costs regarding snake bite care.

Chandler received nine vials of intravenous antivenom treatments at Duke Health following his bite in May. Each vial cost about $11,000, he said, but his insurance lowered the cost to $255 total.

“I’m glad to know that this pill might lower these costs, because there aren’t that many people who have $100,000 laying around in case they get bitten by a snake,” Chandler said. “I didn’t pay that much, and thankfully, I’m perfectly fine. Playing golf with my granddaughter and enjoying my life, just a month after a bite.”

A typical initial dose of antivenom is four to six vials, UNC Health previously told The N&O. The total charge for the treatment at a UNC facility can range from $76,000 to $115,000.

At Hilton Head Island Hospital, the black line on Carolyn Bivens Cote’s hand was used to measure swelling over time from the copperhead snakebite on her left index finger.
At Hilton Head Island Hospital, the black line on Carolyn Bivens Cote’s hand was used to measure swelling over time from the copperhead snakebite on her left index finger.

A scramble for antivenom

Local hospitals are sometimes called on to treat bites from non-native snakes, and that antivenom is harder to come by.

Typically, the only exotic antivenoms in the U.S. are held by zoos or aquariums that keep venomous snakes, Dustin Smith, Curator of Herpetology at the North Carolina Zoo told The News & Observer for a previous report. The antivenoms are expensive and have a short shelf life, he said.

In 2016, the Riverbanks Zoo & Garden in South Carolina provided antivenom when Ali Iyoob of Chapel Hill was bitten by his pet king cobra. EMS workers found Iyoob on N.C. 54, about two miles west of Carrboro, where he became sick while trying to drive himself to the hospital. The antivenom had to be flown inside a cooler from the zoo to Chapel Hill.

The same zoo provided antivenom in March 2021, when Christopher Gifford of Raleigh suffered a near-fatal bite from a pet green mamba snake. Gifford, who made news a few months later when his spitting zebra cobra went missing in his north Raleigh neighborhood, said in a Facebook post at the time that his recovery required four vials of antivenom and a 42-hour hospital stay.

What’s it like getting bit by a copperhead?

“I thought it was a bee sting,” Chandler said.

After an afternoon of yard work, Chandler noticed his shed door was open, and a storm was coming. So he threw on some slippers and walked out to the storage unit.

“I lifted up my foot and saw those two signature snake marks with some blood running out of them, then I turn around and see the snake laying three feet from me,” Chandler said. “I got a shovel, came back and killed him, then I called 9-1-1.”

In the ambulance, the EMT talked to Chandler about dry bites, which are snake bites where no venom is injected into the victim. But Chandler knew he had a venomous bite within five minutes of getting bitten, as his foot began to swell heavily and quickly.

Chandler stayed in the hospital from Saturday morning to late Sunday night, he said. He received nine vials of antivenom through an IV, and he began taking the universal antivenom pills while in the hospital. He was sent home with more pills to take at specific times, and then went to Duke Health clinics for follow-ups.

“It couldn’t have gone any better. You hear horror stories about people who’ve gotten bitten, and I was afraid that would be me,” he said. “I think my neighbor stayed in the hospital for five days when he got bitten. His whole finger, left arm and part of his left side turned completely black. In the end, he only lost his fingernail, which has grown back by now.”

Chandler hopes the study will allow everyone, especially those in developing countries, to have top-notch access to snake bite care.

“We’re fortunate to live here, where we have exceptional medical care,” Chandler said. “I’m 70 — an age in my life where I want to be close to good medical care, and we certainly have it here. Maybe this pill will give access to this kind of care everywhere in the world.”