Big Pharma-backed SonoThera sounds off with $125M series B for bubble-based genetic delivery

Bay Area biotech SonoThera is bubbling to a clinical boil after raising a $125 million series B with the backing of some of the biggest names in pharma.

Vida Ventures led the raise, with the venture arms of UCB, Bayer, Otsuka Pharmaceutical and Johnson & Johnson all pitching in to support SonoThera’s unique delivery system for genetic medicines.

SonoThera will use the raise to push its lead candidate for Duchenne muscular dystrophy (DMD) and an autosomal dominant polycystic kidney disease program into the clinic, the biotech announced in a June 10 release.

The Big Pharma interest stems from the potential for SonoThera’s technology to solve long-standing problems with traditional delivery systems and bring genetic medicines to bigger patient populations, the biotech’s co-founder and CEO, Kenneth Greenberg, Ph.D., told Fierce Biotech.

Viral vectors, the classic shuttle for gene therapies, are especially prone to safety concerns such as liver toxicity and are limited to a single dose because of recognition from the immune system, Greenberg explained. Both viruses and lipid nanoparticles also struggle with complex manufacturing processes, and can’t fit large amounts of DNA or RNA at once.

“Most of the large pharmas have been battling against these same challenges with their internal programs,” Greenberg said. They also recognize that SonoThera’s approach “could allow the application of gene therapy into chronic prevalent diseases with much greater populations than rare disease[s].”

SonoThera’s solution was invented by the company’s chief scientific officer and co-founder Steve Feinstein, M.D., back in the 1990s. A cardiologist, Feinstein noticed there was no way to produce contrast when using ultrasound on the heart, making imaging difficult.

He created microbubbles as a way to better view the blood-pumping organ, Greenberg told Fierce. “He created the entire field of contrast ultrasound by inventing the first two FDA-approved microbubbles.”

It wasn’t long until Feinstein recognized that the tiny bubbles could also be used to help deliver medicines, and he, Greenberg and the other co-founders teamed up to launch the company in 2022.

The process works like this, Greenberg said: naked DNA or RNA is infused into the patient’s body alongside a stream of microbubbles. Ultrasound is then beamed onto the target organ, which activates the bubbles and causes them to open gaps in the blood vessels that serve as a path to the organ’s tissues. The same ultrasound, the components of which are all already established and FDA approved, then makes the bubbles pop, opening pores in the organ’s cells that the genetic payload can slip through.

The whole procedure can be done in under an hour, according to SonoThera’s release.

“We really wanted to build a platform that would enable patient access and adoption by the clinical community without having novel hardware and additional regulatory hurdles,” the CEO said.

With $125 million more now in the safe, the biggest test is set to come for SonoThera’s unique technique. The biotech plans to launch its DMD clinical trial next year, using its bubble-assisted delivery to ship the full-length dystrophin gene to patients.

Dystrophin is the key muscle protein lacking in DMD, but the gene that makes it is too large to fit into traditional adeno-associated virus (AAV) or nanoparticle vectors. This is why existing medicines, like Sarepta Therapeutics’ Elevidys, instead use a shortened form of the gene, or why other approaches try to target specific disease-causing mutations.