Water Vapor Ablation Therapy Shows Encouraging Efficacy, Safety in Prostate Cancer

Christopher Warlick, MD, PhD

A water vapor ablation therapy has been shown to be able to reach and treat all prostate regions and eradicate intermediate risk, grade group 2 (GG2, Gleason score 3+4) prostate cancer with acceptable safety and tolerability, according to 6-month data from the VAPOR 1 trial (NCT04087980).¹

The technology reached regions such as the apex, mid, base, anterior, and posterior. Moreover, 6-month biopsy results revealed that 87% of the 15 patients enrolled to the trial did not have GG2 or worse disease on the treated side. In 3 patients, data on the treated side revealed a single positive biopsy core with 5% or less involvement of GG1 (Gleason Score 3+3) disease.

Additionally, no serious adverse effects (AEs) were reported with the approach, and no device-related toxicities were observed. Moreover, no unanticipated toxicities with the device occurred.

“I am excited to be participating in the VAPOR 1 trial,” Christopher Warlick, MD, PhD, principal investigator of VAPOR 1 and head of the Department of Urology at the University of Minnesota, stated in a press release. “Currently, urologists commonly use water vapor to successfully treat benign prostatic hyperplasia. The VAPOR 1 results are very encouraging and suggest the viability of water vapor technology to treat prostate cancer, as well. This approach has the potential to provide appropriate men a simple outpatient procedure to manage their prostate cancer with minimal risk of the debilitating [AEs] often seen with other therapies.”

Thermal water vapor energy technology was developed to utilize phase shift energy stored in sterile water vapor to convectively transfer thermal energy to cancer tissue to provoke cell death.² Cancer ablation via water vapor is fueled by the energy that is generated when liquid water converts to vapor, or steam.

When water changes to vapor at approximately 100 degrees Celsius, a phase shift happens. Notably, the water vapor that is produced from this process carries over fivefold the energy of water of the same mass. When this vapor is administered to the targeted tissue, the thermal energy that is stored is discharged onto the cancer cells as the vapor condenses back to its liquid state. The transfer of energy results in ablation of the cellular membrane, which results in cancer cell death.

The majority of the ablative technologies used in clinical practice utilize thermal energy that stems from a single point that is either hot or cold. The energy then transfers from cell to cell and progressively gets cooler, or warmer, the further from the source that it gets; this leads to heating or cooling that is uneven and can be challenging to control, according to Francis Medical, the device developer.

With water vapor technology, the vapor is given under pressure and moves through the space between the cells over the course of a few seconds. The energy produced is evenly distributed throughout the area and ablates uniformly as the vapor changes back to water.

In the prospective, multicenter, single-arm study, investigators enrolled 15 patients with intermediate-risk, localized prostate cancer at 4 clinical sites in the United States. Participants had unilateral cancer and the treatment intent was to ablate only the impacted side.

The primary outcome measure for the trial is serious device-related AEs, while secondary measures include AEs, changes from baseline in the Expanded Prostate Cancer Index Questionnaire, changes from baseline in the International Index of Erectile Function Questionnaire, changes from baseline in the International Prostate Cancer Symptom Score, and changes from baseline in the Male Sexual Health Ejaculatory Function Short Form Questionnaire, among others.³

Additional safety data at the 6-month time point showed low levels of AEs with the approach, with no participants experiencing urinary incontinence requiring pad usage. Only 1 patient (6.7%) reported moderate erectile dysfunction with the therapy.

The data support the intent of the therapy to manage clinically significant disease while reducing morbidities linked with treatments that are currently utilized. Participants from the study will continued to be followed for 1 year.

The company also announced that they will use the safety and efficacy data produced in the trial to support another pivotal trial that will further examine the device, as well as regulatory approval for its use in this indication in the United States.

“The VAPOR 1 results are the culmination of the hard work and shared vision of the entire Francis Medical team,” Michael Hoey, founder and chief medical officer of Francis Medical, added in the press release. “At Francis Medical, the patient is always first and foremost in our minds. Therefore, it is extremely gratifying to provide the patients in VAPOR 1 with not only an effective treatment for their cancer, but also one that produced minimal pain and [AEs], allowing them to quickly return to their normal activities. We continue to work hard every day to realize our shared goal to bring this therapy to every man who can benefit from it.”

References

1. Francis Medical announces positive data from VAPOR 1 IDE for water vapor ablation of prostate cancer. News release. Francis Medical, Inc. June 8, 2021. Accessed June 12, 2021. https://bit.ly/3cITvxU
2. Technology. Francis Medical, Inc. Accessed June 12, 2021. https://bit.ly/3pZf2rp
3. Ablation of prostate tissue utilizing sterile water vapor in patients with intermediate risk localized prostate cancer. ClinicalTrials.gov. Updated December 16, 2020. Accessed June 12, 2021. https://clinicaltrials.gov/ct2/show/NCT04087980