Phase 3 Study of ProstAtak® Immunotherapy With Standard Radiation Therapy for Localized Prostate Cancer (PrTK03)
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ClinicalTrials.gov Identifier: NCT01436968 |
Recruitment Status :
Active, not recruiting
First Posted : September 20, 2011
Last Update Posted : May 10, 2023
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Condition or disease | Intervention/treatment | Phase |
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Prostate Cancer | Biological: Aglatimagene besadenovec + valacyclovir Biological: Placebo + valacyclovir | Phase 3 |
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 711 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor) |
Primary Purpose: | Treatment |
Official Title: | A Randomized Controlled Trial of ProstAtak® as Adjuvant to Up-front Radiation Therapy For Localized Prostate Cancer |
Study Start Date : | September 2011 |
Estimated Primary Completion Date : | December 2024 |
Estimated Study Completion Date : | December 2024 |

Arm | Intervention/treatment |
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Experimental: ProstAtak®
Aglatimagene besadenovec (CAN-2409) + valacyclovir + radiation therapy +/- ADT
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Biological: Aglatimagene besadenovec + valacyclovir
Patients will receive three courses of ProstAtak® each consisting of aglatimagene besadenovec injection + oral valacyclovir. AdV-tk injection will be delivered to the prostate via trans-rectal ultrasound guided injection as follows:
The prodrug, valacyclovir, will be administered at a fixed dose for 14 days after each AdV-tk injection. Standard external beam radiation therapy will be delivered to the prostate. Short-term androgen deprivation therapy (maximum of 6 months) is optional but must be decided before enrollment to allow for stratification. Other Names:
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Placebo Comparator: Control
Placebo + valacyclovir + radiation therapy +/- ADT
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Biological: Placebo + valacyclovir
Patients will receive three courses each consisting of placebo injection + oral valacyclovir. Placebo injection will be delivered to the prostate via trans-rectal ultrasound guided injection as follows:
The prodrug, valacyclovir, will be administered at a fixed dose for 14 days after each placebo injection. Standard external beam radiation therapy will be delivered to the prostate. Short-term androgen deprivation therapy (maximum of 6 months) is optional but must be decided before enrollment to allow for stratification. |
- Disease free survival defined as the time from randomization until the date of the first failure event will be compared for the ProstAtak® arm versus the placebo control arm. The analyses will be based on the intent to treat population. [ Time Frame: Assessed at each visit every 6 months through year 5 until event occurs. ]
- Prostate cancer specific survival and overall survival will be compared for the ProstAtak® arm versus the placebo control arm. [ Time Frame: Assessed at each visit every 6 months through year 5 after which long-term follow up of general health status will continue yearly. ]
- PSA nadir will be compared for the ProstAtak® arm versus the placebo control arm. [ Time Frame: Assessed at each visit every 6 months through year 5. ]
- Patient reported Health Related Quality of Life outcomes will be collected using the Expanded Prostate Cancer Index Composite (EPIC-26) questionnaire. The change in QOL over time will be compared for the ProstAtak® arm versus the placebo control arm. [ Time Frame: Assessed at baseline and at 3, 6, 12, 18 and 24 months after completion of radiation. ]
- The safety profile will be characterized by collection of adverse event information and laboratory values during the treatment phase (until the completion of radiation). Data on late effects will be collected after radiation completion. [ Time Frame: Assessed at each visit and continuously throughout the study. ]

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Ages Eligible for Study: | 18 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | Male |
Accepts Healthy Volunteers: | No |
Inclusion Criteria include:
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Localized prostate cancer meeting the NCCN criteria of Intermediate Risk or patients having only one NCCN high-risk feature
- NCCN Intermediate Risk is defined as having at least one of the following: PSA 10-20 ng/ml, Gleason score =7, T2b-T2c
- High Risk with a single high risk feature is defined as having only one of the following: PSA>20 ng/ml, Gleason score 8-10, or T3a
- Excluded are those in the following risk groups: Low risk; High risk with more than 1 high risk factor; Locally advanced/very high risk=T3b-T4; Metastatic: N1 or M1
- Planning to undergo standard prostate-only external beam radiation therapy
- ECOG Performance Status 0-2
Exclusion Criteria include:
- Liver disease, including known cirrhosis or active hepatitis
- Patients on systemic corticosteroids (>10mg prednisone per day) or other immunosuppressive drugs
- Known HIV+ patients
- Regional lymph node involvement or distant metastases
- Patients planning to receive whole pelvic irradiation
- Prior treatment for prostate cancer, except TURP or ADT. For ADT, it may only be given for a maximum of 6 months
- Patients who had or plan to have orchiectomy as the form of hormonal ablation
- Known sensitivity or allergic reactions to acyclovir or valacyclovir

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01436968

Responsible Party: | Candel Therapeutics, Inc. |
ClinicalTrials.gov Identifier: | NCT01436968 |
Other Study ID Numbers: |
PrTK03 |
First Posted: | September 20, 2011 Key Record Dates |
Last Update Posted: | May 10, 2023 |
Last Verified: | May 2023 |
immunotherapy, cytotoxicity, tumor vaccine, prostate cancer, radiotherapy |
Prostatic Neoplasms Genital Neoplasms, Male Urogenital Neoplasms Neoplasms by Site Neoplasms Genital Diseases, Male Genital Diseases |
Urogenital Diseases Prostatic Diseases Male Urogenital Diseases Valacyclovir Antiviral Agents Anti-Infective Agents |