A San Francisco, California-based medical device startup, Zenflow, has announced a $31.4 million Series A financing round to further its minimally-invasive approach to treating benign prostatic hyperplasia (BPH) or enlarged prostate.

The condition affects half of all men between the ages of 51 and 60, and up to 90 percent of men greater than 80 years of age. It occurs when the prostate gland becomes enlarged (but not cancerous) and encroaches on the urinary tract.

Zenflow’s solution is a device to prop open the urethra, thereby mitigating the symptoms of BPH without the need for surgery or medications. Dubbed the Spring System, it was designed by a team of Stanford Biodesign Innovation Fellows, including Nick Damiano and Shreya Mehta who went on to found the company in 2014.

In a phone interview, Damiano said the startup “threw out a broad net” for funding and between 2015 and 2017, it hauled in $5.2 million in seed funding, mostly from angel investors.

Along the way, it was supported by the StartX accelerator and the Rosenman Institute that focuses on medical device innovation at QB3, which is University of California’s hub for innovation and entrepreneurship in the life sciences. A notable partnership was also struck with Y Combinator, a popular Silicon Valley accelerator that typically backs technology companies (think Airbnb, Dropbox, and Reddit). Zenflow became the first medical device startup in the program’s 10-year history.

This week’s Series A was another group effort. Invus Opportunities, F-Prime Capital Partners, and Medical Technology Venture Partners led the round with a consortium of smaller investors, including Stanford-StartX Fund, SV Tech Ventures, and ShangBay Capital among others.

According to Damiano, the money will give the company a long runway and potentially move them through an FDA approval. From there, it all rests on the technology and how well it can edge out its competitors.

A surgical intervention known as TURP (transurethral resection of the prostate) has long been the gold standard for advanced BPH. And there are medications, approved many years ago, that can help control the symptoms. What was lacking was, he believes is a middle-ground that could address the underlying issue without the risks and side effects of the existing options.

Zenflow’s Spring System involves a minimally-invasive procedure that delivers a low-profile superelastic implant into the prostatic urethra. It’s paired with a thin, flexible catheter with built-in visualization, allowing the patient’s urologist to perform the procedure using just a local anesthetic. There is no cutting, heating, or removal of prostate tissue.

While it’s early days – patients have now been followed a little over 12 months – Damiano said the system is designed to permanently relieve BPH complications. Based on a 2016 trial, called ZEST, the company is also reporting “promising evidence of safety.”

Zenflow is one of several companies developing non-surgical treatments for BPH. While that may increase the challenge, Damiano believes it also shows demand for the product is there.

One competitor, he pointed to, is Neotract,  which gained FDA clearance for its UroLift System in 2013. The company uses small implants that hold the enlarged prostate tissue out of the way, like a miniature reinforcing wall for the urethra.Four years later it was acquired by Teleflex Incorporated in a deal worth up to $1.1 billion.

“They really did a good job with the company, so we were happy to see they’ve done well,” Damiano said, adding that Zenflow believes there’s still “a good space” for its Spring System if it reaches the market.

Both procedures are designed around small implants. An alternative approach is to ‘ablate’ or erode the excess prostate tissue in a targeted way.

Maple Grove, Minnesota-based NxThera does this with its FDA-approved Rezu?m System, which delivers ‘radiofrequency generated thermal therapy’ in the form of water vapor. An earlier-stage company, Procept Biorobotics, uses a combination of ‘aquablation’ and autonomous robotics. A third, Sophiris Bio, is developing a therapy that involves the localized injection of a drug, topsalysin, which activates in the presence of prostate-specific antigen (PSA).

Given an estimated 400 million men worldwide have an enlarged prostate, there’s likely enough room for all therapies, based on an individual’s condition and personal preference. Put together, this new wave of innovation could shift the BPH treatment paradigm from operating room surgeries to outpatient procedures that any urologist may perform.