Zenflow, Inc., a privately held medical device company based in the San Francisco Bay Area, today announced the closing of a $31.4 million Series A equity financing round led by Invus Opportunities, F-Prime Capital Partners, and Medical Technology Venture Partners. Other new and existing investors participated alongside the leads. Zenflow has also received grant funding from the National Institutes of Health (NIH) and National Science Foundation (NSF).

Zenflow develops minimally invasive devices to treat obstructive urinary symptoms related to benign prostatic hyperplasia (BPH or enlarged prostate). Its first product is the Spring System, a technology that delivers a low-profile superelastic implant into the prostatic urethra. By providing therapy through a thin, flexible catheter with built-in visualization, the Spring System is designed to provide a simple procedure for the physician and the most patient-friendly solution on the market. This system is intended to permanently relieve BPH symptoms in a single procedure with fast recovery and minimal side effects.

"The Zenflow Spring System is a promising new treatment option for men suffering from BPH symptoms," said Dr. Harcharan Gill, Professor of Urology at Stanford University. "The device can be deployed in a simple procedure in the urologist's office under direct visualization through a flexible delivery system, which should minimize patient discomfort. I look forward to seeing the results of the upcoming clinical trials."


Zenflow was founded by Nick Damiano and Shreya Mehta out of the Stanford Biodesign Innovation Fellowship in 2014 and went on to become one of the first medical device companies to be funded by the Y Combinator accelerator. The company has also been supported by the StartX accelerator and the Rosenman Institute at QB3.

"Before founding this company, we interviewed a lot of BPH patients in the urology clinic and were astounded by the impact that the disease had on their quality of life," said Nick Damiano, Co-Founder and Chief Executive Officer of Zenflow. "Since then, we've been able to build a talented and experienced team that is as motivated to help these patients as Shreya and I were when we founded Zenflow. The strong investor interest in this funding round validates the importance of this clinical need and the accomplishments of our team so far. We're looking forward to the exciting next steps where we will see our technology have a real impact on patients' lives."

In 2016, Zenflow initiated the ZEST Study, a first-in-human safety and feasibility trial of the Spring System, led by Principal Investigator Dr. Peter Gilling in Tauranga, New Zealand. All patients from this study have now been followed beyond 12 months, and the company reports promising evidence of safety and lasting symptom relief.

This round of financing will be used to perform additional clinical studies that will serve to further validate safety and effectiveness of the Spring System, and to prepare for commercial launch. The company anticipates enrolling patients in the UK, Australia, New Zealand, and Mexico in 2018 while pursuing Investigational Device Exemption (IDE) approval from FDA to initiate a pivotal trial in the United States.


BPH is a non-cancerous enlargement of the prostate gland that most men experience as they age. Nearly half of men have symptoms associated with an enlarged prostate by age 50, and up to 90% of men develop the condition by age 80. BPH leads to urinary retention, frequency, and urgency, which result in anxiety, loss of sleep, and interference with daily activities. Medications are widely prescribed but can have adverse effects such as loss of libido and prove ineffective for a large fraction of patients. Surgery is effective but can result in post-operative pain and carries a high risk of permanent sexual side effects such as retrograde ejaculation and erectile dysfunction.