Clinical Evaluation of BackStop in Patients Undergoing Ureteroscopic Lithotripsy

• Sponsor: University of Southern California (Other)
• Overall Status: Terminated
• CT.gov ID: NCT02122341
• Collaborator: Urology of Virginia (Other)
• Enrollment: 35
• Locations: 2
• Arms: 2
• Duration (Months): 27
• Patients Per Site: 17.5
• Patients Per Site Per Month: 0.6

Study Details

Study Description

Brief Summary

The purpose of this clinical study is to evaluate BackStop, a polymer-based device that is intended to be used during ureteroscopic lithotripsy to prevent retrograde stone migration.

Condition or Disease	Intervention/Treatment	Phase
Kidney Stones	Device: BackStop	N/A

Detailed Description

During ureteroscopic treatment for ureteral stones, lithotripsy, irrigation, and manipulation of the stone often pushes stone away into the kidney itself. This phenomenon is called retropulsion, which is defined as clinically significant retrograde migration of stone or stone fragments. Movement of stones retrograde into the renal pelvis could potentially add and complicate the surgery further. Often scopes need to be changed in order to reach the stone, and chasing these stones will add time to the surgery and require more valuable resources. Furthermore, sometimes a second operation will need to be done when these retropulsed fragments could not be all found and cleaned out.

A number of devices have been developed to prevent such migration including stone baskets and conical devices. These are wire-based devices which have the potential of injuring the ureter. Because of safety concerns and that there is limited data available on the effectiveness of these devices; these are not widely used by urologists. BackStop has recently been developed as another tool to prevent retropulsion. It is a water soluble gel that is injected proximal to the stone. This creates a physical barrier that prevents stone migration during ureteroscopic lithotripsy for ureteral calculus.

Study Design

• Study Type: Interventional
• Actual Enrollment: 35 participants
• Allocation: Randomized
• Intervention Model: Parallel Assignment
• Masking: Single (Participant)
• Primary Purpose: Treatment
• Official Title: Post FDA-Approval Clinical Evaluation of BackStopTM in Patients Undergoing Ureteroscopic Lithotripsy: A Prospective, Randomized Clinical Trial
• Study Start Date: Apr 1, 2014
• Actual Primary Completion Date: Jun 1, 2016
• Actual Study Completion Date: Jul 1, 2016

Arms and Interventions

Arm	Intervention/Treatment
Experimental: BackStop Patients randomized to the Experimental arm will receive the BackStop gel during their ureteroscopic lithotripsy to prevent retrograde migration of stones or stone fragments.	Device: BackStop; BackStop™ is a FDA approved device. It is intended for use during ureteroscopic lithotripsy to prevent retrograde migration of stones and stone fragments. It is comprised of a solution of a thermosensitive polymer, a purified version of poloxamer 407 having been fractionated in saline. BackStop™, which is injected above the stone, is provided in sterile, pre-filled 2.5ml and 5ml syringes along with and a corresponding injector and a catheter (3F or 5F).
No Intervention: Control Patients randomized to the control group will not use any devices to prevent retrograde migration of stones and stone fragments during their ureteroscopic lithotripsy.

Outcome Measures

Primary Outcome Measures

1. Rate of Prevention of Retrograde Stone or Stone Fragment Migration [At the time of surgery]

   Prevention of retrograde stone migration (Yes/No)

Secondary Outcome Measures

1. Stone-free Rate [2 months]

   Presence or absence of residual stone fragments at 2 month follow up after lithotripsy

Other Outcome Measures

1. Need for Secondary Procedures [Up to 3 months]

   Need for secondary procedures of patients who had stone migration

2. Time for BackStop Injection [Minutes during Surgery]

   Time required to deliver BackStop beginning with insertion of BackStop catheter and ending with its removal subsequent to the delivery of BackStop

3. Duration of Lithotripsy Procedure [during surgery]

   Duration of Lithotripsy Procedure

Eligibility Criteria

Criteria

• Ages Eligible for Study: 18 Years and Older
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: No

Inclusion Criteria:

• patient with solitary ureteral stone ranging from 5mm to 15mm diameter

• able to tolerate general anesthesia

• clinical indication for treatment by ureteroscopic lithotripsy

• must be willing and able to participate in any follow-up visits

• provide informed consent

• have a CT scan demonstrating the stone

Exclusion Criteria:

• patients undergoing extracorporeal shock wave lithotripsy (ESWL) or any other extracorporeal or percutaneous lithotripsy procedure as primary procedure

• any co-morbidity or condition that would necessitate exclusion of patient (physician opinion)

• renal or ureteral anatomical abnormality

• multiple stones in the indicated ureter

• stones in the indicated kidney

• patient is immunocompromised

• multiple organ dysfunction syndrome

• has an absolute or relative solitary kidney mass

• = Stage 3 chronic kidney disease

• bilateral ureteral obstructing stones

• staghorn calculi

• impaction of several stone fragments (Steinstrasse)

• uncorrected coagulopathy/thrombocytopenia

• urethral and/or ureteral stricture

• reconstructive urinary surgery

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	USC Institute of Urology	Los Angeles	California	United States	90089
2	Urology of Virginia	Virginia Beach	Virginia	United States	23462

Sponsors and Collaborators

• University of Southern California
• Urology of Virginia

Investigators

• Principal Investigator: Matthew Dunn, M.D., USC Institute of Urology

Study Documents (Full-Text)

None provided.

More Information

Additional Information:

• FDA MAUDE database online (accessed date July 8, 2007)

Publications

• Chow GK, Patterson DE, Blute ML, Segura JW. Ureteroscopy: effect of technology and technique on clinical practice. J Urol. 2003 Jul;170(1):99-102.
• Hendrikx AJ, Strijbos WE, de Knijff DW, Kums JJ, Doesburg WH, Lemmens WA. Treatment for extended-mid and distal ureteral stones: SWL or ureteroscopy? Results of a multicenter study. J Endourol. 1999 Dec;13(10):727-33.
• International Conference on Harmonisation of technical requirements for registration of pharmaceuticals for human use. ICH harmonized tripartite guideline: Guideline for Good Clinical Practice. J Postgrad Med. 2001 Jan-Mar;47(1):45-50.
• Knispel HH, Klän R, Heicappell R, Miller K. Pneumatic lithotripsy applied through deflected working channel of miniureteroscope: results in 143 patients. J Endourol. 1998 Dec;12(6):513-5.
• Pardalidis NP, Kosmaoglou EV, Kapotis CG. Endoscopy vs. extracorporeal shockwave lithotripsy in the treatment of distal ureteral stones: ten years' experience. J Endourol. 1999 Apr;13(3):161-4.
• Rane A, Bradoo A, Rao P, Shivde S, Elhilali M, Anidjar M, Pace K, D'A Honey JR. The use of a novel reverse thermosensitive polymer to prevent ureteral stone retropulsion during intracorporeal lithotripsy: a randomized, controlled trial. J Urol. 2010 Apr;183(4):1417-21. doi: 10.1016/j.juro.2009.12.023. Epub 2010 Feb 20.
• Robert M, Bennani A, Guiter J, Avérous M, Grasset D. Treatment of 150 ureteric calculi with the Lithoclast. Eur Urol. 1994;26(3):212-5.
• Segura JW, Preminger GM, Assimos DG, Dretler SP, Kahn RI, Lingeman JE, Macaluso JN Jr. Ureteral Stones Clinical Guidelines Panel summary report on the management of ureteral calculi. The American Urological Association. J Urol. 1997 Nov;158(5):1915-21.

• Responsible Party: University of Southern California
• ClinicalTrials.gov Identifier: NCT02122341
• Other Study ID Numbers: HS-12-00714
• First Posted: Apr 24, 2014
• Last Update Posted: May 22, 2019
• Last Verified: Apr 1, 2019

• Individual Participant Data (IPD) Sharing Statement: No
• Plan to Share IPD: No
• Additional relevant MeSH terms: Kidney Calculi

Study Results

Participant Flow

Arm/Group Title	Experimental: BackStop	No Intervention: Control
Arm/Group Description	Patients randomized to the Experimental arm will receive the BackStop gel during their ureteroscopic lithotripsy to prevent retrograde migration of stones or stone fragments. BackStop: BackStop™ is a FDA approved device. It is intended for use during ureteroscopic lithotripsy to prevent retrograde migration of stones and stone fragments. It is comprised of a solution of a thermosensitive polymer, a purified version of poloxamer 407 having been fractionated in saline. BackStop™, which is injected above the stone, is provided in sterile, pre-filled 2.5ml and 5ml syringes along with and a corresponding injector and a catheter (3F or 5F).	Patients randomized to the control group will not use any devices to prevent retrograde migration of stones and stone fragments during their ureteroscopic lithotripsy.
Period Title: Overall Study
STARTED	17	18
COMPLETED	17	18
NOT COMPLETED	0	0

Baseline Characteristics

Arm/Group Title	Experimental: Backstop	No Intervention: Control	Total
Arm/Group Description	Patients randomized to the Experimental arm will receive the BackStop gel during their ureteroscopic lithotripsy to prevent retrograde migration of stones or stone fragments. BackStop: BackStop™ is a FDA approved device. It is intended for use during ureteroscopic lithotripsy to prevent retrograde migration of stones and stone fragments. It is comprised of a solution of a thermosensitive polymer, a purified version of poloxamer 407 having been fractionated in saline. BackStop™, which is injected above the stone, is provided in sterile, pre-filled 2.5ml and 5ml syringes along with and a corresponding injector and a catheter (3F or 5F).	Patients randomized to the control group will not use any devices to prevent retrograde migration of stones and stone fragments during their ureteroscopic lithotripsy.	Total of all reporting groups
Overall Participants	17	18	35
Age (Count of Participants)
<=18 years	0 0%	0 0%	0 0%
Between 18 and 65 years	15 88.2%	12 66.7%	27 77.1%
>=65 years	2 11.8%	6 33.3%	8 22.9%
Sex: Female, Male (Count of Participants)
Female	8 47.1%	5 27.8%	13 37.1%
Male	9 52.9%	13 72.2%	22 62.9%
Ethnicity (NIH/OMB) (Count of Participants)
Hispanic or Latino	4 23.5%	5 27.8%	9 25.7%
Not Hispanic or Latino	12 70.6%	12 66.7%	24 68.6%
Unknown or Not Reported	1 5.9%	1 5.6%	2 5.7%
Race (NIH/OMB) (Count of Participants)
American Indian or Alaska Native	0 0%	0 0%	0 0%
Asian	2 11.8%	1 5.6%	3 8.6%
Native Hawaiian or Other Pacific Islander	0 0%	0 0%	0 0%
Black or African American	4 23.5%	1 5.6%	5 14.3%
White	7 41.2%	11 61.1%	18 51.4%
More than one race	0 0%	0 0%	0 0%
Unknown or Not Reported	4 23.5%	5 27.8%	9 25.7%
Region of Enrollment (participants) [Number]
United States	17 100%	18 100%	35 100%

Outcome Measures

1. Primary Outcome

Title	Rate of Prevention of Retrograde Stone or Stone Fragment Migration
Description	Prevention of retrograde stone migration (Yes/No)
Time Frame	At the time of surgery

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Investigational: BackStop	No Intervention: Control
Arm/Group Description	Patients randomized to the Experimental arm will receive the BackStop gel during their ureteroscopic lithotripsy to prevent retrograde migration of stones or stone fragments. BackStop: BackStop™ is a FDA approved device. It is intended for use during ureteroscopic lithotripsy to prevent retrograde migration of stones and stone fragments. It is comprised of a solution of a thermosensitive polymer, a purified version of poloxamer 407 having been fractionated in saline. BackStop™, which is injected above the stone, is provided in sterile, pre-filled 2.5ml and 5ml syringes along with and a corresponding injector and a catheter (3F or 5F).	Patients randomized to the control group will not use any devices to prevent retrograde migration of stones and stone fragments during their ureteroscopic lithotripsy.
Measure Participants	17	18
Yes	14 82.4%	11 61.1%
No	3 17.6%	7 38.9%

2. Secondary Outcome

Title	Stone-free Rate
Description	Presence or absence of residual stone fragments at 2 month follow up after lithotripsy
Time Frame	2 months

Outcome Measure Data

Analysis Population Description

Number of patients analyzed is inconsistent with numbers provided in participant flow module due to patients lost to follow up

Arm/Group Title	Investigational: BackStop	No Intervention: Control
Arm/Group Description	Patients randomized to the Experimental arm will receive the BackStop gel during their ureteroscopic lithotripsy to prevent retrograde migration of stones or stone fragments. BackStop: BackStop™ is a FDA approved device. It is intended for use during ureteroscopic lithotripsy to prevent retrograde migration of stones and stone fragments. It is comprised of a solution of a thermosensitive polymer, a purified version of poloxamer 407 having been fractionated in saline. BackStop™, which is injected above the stone, is provided in sterile, pre-filled 2.5ml and 5ml syringes along with and a corresponding injector and a catheter (3F or 5F).	Patients randomized to the control group will not use any devices to prevent retrograde migration of stones and stone fragments during their ureteroscopic lithotripsy.
Measure Participants	9	10
Present	9 52.9%	10 55.6%
Absent	0 0%	0 0%

3. Other Pre-specified Outcome

Title	Need for Secondary Procedures
Description	Need for secondary procedures of patients who had stone migration
Time Frame	Up to 3 months

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Investigational: BackStop	No Intervention: Control
Arm/Group Description	Patients randomized to the Experimental arm will receive the BackStop gel during their ureteroscopic lithotripsy to prevent retrograde migration of stones or stone fragments. BackStop: BackStop™ is a FDA approved device. It is intended for use during ureteroscopic lithotripsy to prevent retrograde migration of stones and stone fragments. It is comprised of a solution of a thermosensitive polymer, a purified version of poloxamer 407 having been fractionated in saline. BackStop™, which is injected above the stone, is provided in sterile, pre-filled 2.5ml and 5ml syringes along with and a corresponding injector and a catheter (3F or 5F).	Patients randomized to the control group will not use any devices to prevent retrograde migration of stones and stone fragments during their ureteroscopic lithotripsy.
Measure Participants	3	7
Yes	0 0%	0 0%
No	3 17.6%	7 38.9%

4. Other Pre-specified Outcome

Title	Time for BackStop Injection
Description	Time required to deliver BackStop beginning with insertion of BackStop catheter and ending with its removal subsequent to the delivery of BackStop
Time Frame	Minutes during Surgery

Outcome Measure Data

Analysis Population Description

The control group did not receive BackStop injection

Arm/Group Title	Investigational: BackStop	No Intervention: Control
Arm/Group Description	Patients randomized to the Experimental arm will receive the BackStop gel during their ureteroscopic lithotripsy to prevent retrograde migration of stones or stone fragments. BackStop: BackStop™ is a FDA approved device. It is intended for use during ureteroscopic lithotripsy to prevent retrograde migration of stones and stone fragments. It is comprised of a solution of a thermosensitive polymer, a purified version of poloxamer 407 having been fractionated in saline. BackStop™, which is injected above the stone, is provided in sterile, pre-filled 2.5ml and 5ml syringes along with and a corresponding injector and a catheter (3F or 5F).	Patients randomized to the control group will not use any devices to prevent retrograde migration of stones and stone fragments during their ureteroscopic lithotripsy.
Measure Participants	17	0
Mean (Full Range) [minutes]	3.04

5. Other Pre-specified Outcome

Title	Duration of Lithotripsy Procedure
Description	Duration of Lithotripsy Procedure
Time Frame	during surgery

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Investigational: BackStop	No Intervention: Control
Arm/Group Description	Patients randomized to the Experimental arm will receive the BackStop gel during their ureteroscopic lithotripsy to prevent retrograde migration of stones or stone fragments. BackStop: BackStop™ is a FDA approved device. It is intended for use during ureteroscopic lithotripsy to prevent retrograde migration of stones and stone fragments. It is comprised of a solution of a thermosensitive polymer, a purified version of poloxamer 407 having been fractionated in saline. BackStop™, which is injected above the stone, is provided in sterile, pre-filled 2.5ml and 5ml syringes along with and a corresponding injector and a catheter (3F or 5F).	Patients randomized to the control group will not use any devices to prevent retrograde migration of stones and stone fragments during their ureteroscopic lithotripsy.
Measure Participants	17	18
Mean (Full Range) [minutes]	4.17	6.09

Adverse Events

Arm/Group Title	Investigational: BackStop		No Intervention: Control
Arm/Group Description	Patients randomized to the Experimental arm will receive the BackStop gel during their ureteroscopic lithotripsy to prevent retrograde migration of stones or stone fragments. BackStop: BackStop™ is a FDA approved device. It is intended for use during ureteroscopic lithotripsy to prevent retrograde migration of stones and stone fragments. It is comprised of a solution of a thermosensitive polymer, a purified version of poloxamer 407 having been fractionated in saline. BackStop™, which is injected above the stone, is provided in sterile, pre-filled 2.5ml and 5ml syringes along with and a corresponding injector and a catheter (3F or 5F).		Patients randomized to the control group will not use any devices to prevent retrograde migration of stones and stone fragments during their ureteroscopic lithotripsy.
All Cause Mortality
	Investigational: BackStop		No Intervention: Control
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	/ (NaN)		/ (NaN)
Serious Adverse Events
	Investigational: BackStop		No Intervention: Control
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/17 (0%)		0/18 (0%)
Other (Not Including Serious) Adverse Events
	Investigational: BackStop		No Intervention: Control
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	4/17 (23.5%)		0/18 (0%)
Gastrointestinal disorders
nausea	2/17 (11.8%)	2	0/18 (0%)	0
vomiting	2/17 (11.8%)	2	0/18 (0%)	0
General disorders
fever	1/17 (5.9%)	1	0/18 (0%)	0
Musculoskeletal and connective tissue disorders
Flank Pain	3/17 (17.6%)	3	0/18 (0%)	0
Renal and urinary disorders
Urinary Retention	1/17 (5.9%)	1	0/18 (0%)	0
hematuria	1/17 (5.9%)	1	0/18 (0%)	0
Urethral Pain	1/17 (5.9%)	1	0/18 (0%)	0

Limitations/Caveats

Study was not able to meet target accrual and was closed early. More patients are needed to fully evaluate the clinical effectiveness of BackStop.

More Information

Certain Agreements

Principal Investigators are NOT employed by the organization sponsoring the study.

There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.