Phase 3 Study of ProstAtak® Immunotherapy With Standard Radiation Therapy for Localized Prostate Cancer

Condition(s) studied

Investigational drug(s) / intervention(s)

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: 1. The first injection will be given at least 15 days and not more than 8 weeks before starting radiation. 2. The second injection will be 0-3 days before initiation of radiation therapy. 3. The third injection will be 15-22 days after the 2nd injection. 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.

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: 1. The first injection will be given at least 15 days and not more than 8 weeks before starting radiation. 2. The second injection will be 0-3 days before initiation of radiation therapy. 3. The third injection will be 15-22 days after the 2nd injection. 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.

Study summary

The purpose of this study is to evaluate the effectiveness of ProstAtak® immunotherapy in combination with radiation therapy for patients with intermediate-high risk localized prostate cancer. ProstAtak kills tumor cells and stimulates a cancer vaccine effect. Killing tumor cells in an immune stimulatory environment induces the body's immune system to detect and destroy cancer cells. ProstAtak has shown synergy with radiation without added toxicity and lower than expected recurrence rates in previous clinical trials. The hypothesis is that ProstAtak can lead to improvement in the clinical outcome for patients with prostate cancer. Participants will be randomized to the ProstAtak or control arm at a 2:1 ratio. Both arms receive standard external beam radiation therapy. Short-term androgen deprivation therapy may be given but is not required.

Eligibility

Primary outcome measure(s)

• 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. — Assessed at each visit every 6 months through year 5 until event occurs.

Trial sites (73)

+ 33 more sites — see the full list on the official registry below.

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