SpaceIT Hydrogel System for Perirectal Spacing

Inclusion Criteria:

Subjects must meet the following criteria to be eligible for participation in the study:

1. Age ≥18 years old

2. Subjects must have had pathologically confirmed (by routine hematoxylin and eosin [H&E] staining) invasive adenocarcinoma of the prostate and planning to undergo EBRT

3. Subjects must meet ALL of the following:

4. Clinical stage T1-T2c (AJCC Ver. 8) tumor AND

5. Gleason Score 7 or less as determined from a biopsy taken within 12 months ofthe Baseline visit AND

6. Demonstrated blood prostate specific antigen (PSA) levels ≤20 ng/ml as measuredwithin 6 months of the Baseline visit and prior to commencing androgendeprivation therapy (ADT)

7. Subject is able to provide written informed consent, approved by the appropriateInstitutional Review Board/Ethics Committee/Research Ethics Board (IRB/EC/REB) ofthe respective clinical site

Exclusion Criteria:

1. Prostate > 80 cc

2. Subjects who are planning to undergo brachytherapy or focal boost

3. Subjects who have magnetic resonance imaging (MRI) evidence of gross posteriorextracapsular extension (ECE) of the prostate cancer Note: MRI must be taken within 6 months prior to the Baseline visit

4. Subjects who have metastatic disease, other ongoing cancers which are being treatedduring the study or subjects for whom pelvic lymph node radiotherapy is planned

5. Subjects with any prior invasive solid tumor malignancy or hematologic malignancy (except non-melanomatous skin cancer) unless the subject has been disease free andtreatment free for a minimum of 3 years

6. History of radical prostatectomy, other ablative anti-prostate cancer therapy (e.g.,cryotherapy, high intensity focused ultrasound, irreversible electroporation) orprevious pelvic irradiation (including prior prostate brachytherapy) at any timeprior to screening

7. History of transurethral prostate surgery (e.g., Transurethral Needle Ablation (TUNA), Transurethral Microwave Therapy (TUMT), Transurethral Resection of theProstate (TURP)) if performed within 1 year prior to screening

8. History of prior pelvic surgery requiring low anterior or abdominoperinealresections or rectal surgery

9. History of or current perirectal disease that may interfere with interpretation ofstudy outcomes, including anal or perianal diseases such as fistula

10. Bleeding hemorrhoids requiring medical intervention within the prior three months

11. Diagnosed active bleeding disorder or a clinically significant coagulopathy, definedas PTT > 70s or aPTT>35s or INR > 1.4, or platelet count < 100,000 per mm3 Note:Subjects on anticoagulants may be included if the anticoagulant medication can beheld for index procedure

12. Active inflammatory or infectious process involving the perineum, GI or urinarytract based on positive diagnosis or suspected diagnosis in the presence of fever >38⁰ C, WBC > 12,000/uL

13. Inability to undergo pelvic MRI or presence of implants causing severe artifact (e.g. bilateral arthroplasty) that interferes with imaging interpretation for thisstudy at Investigator discretion

14. If a subject was enrolled in another investigational drug or device trial that hadnot completed the primary endpoint or that clinically interfered with this study

15. Unable to comply with the study requirements or follow-up schedule

16. Any condition the Investigator believed would interfere with the intent of the studyor would make participation not in the best interest of the patient

17. Known PEG (polyethylene glycol) sensitivity or allergy

18. Known iodine sensitivity or allergy

19. ADT, if applicable, cannot or was not started 15-60 days prior to the pre-indexprocedure RT planning imaging and is planned to continue for a total plannedduration greater than 6 months