Treating Prostate Cancer That Has Come Back After Surgery With Apalutamide and Targeted Radiation Based on PET Imaging

This phase III trial tests two questions by two separate comparisons of therapies. The first question is whether enhanced therapy (apalutamide in combination with abiraterone + prednisone) added to standard of care (prostate radiation therapy and short term androgen deprivation) is more effective compared to standard of care alone in patients with prostate cancer who experience biochemical recurrence (a rise in the blood level of prostate specific antigen [PSA] after surgical removal of the prostate cancer).

A second question tests treatment in patients with biochemical recurrence who show prostate cancer spreading outside the pelvis (metastasis) by positron emission tomography (PET) imaging. In these patients, the benefit of adding metastasis-directed radiation to enhanced therapy (apalutamide in combination with abiraterone + prednisone) is tested.

Diagnostic procedures, such as PET, may help doctors look for cancer that has spread to the pelvis. Androgens are hormones that may cause the growth of prostate cancer cells. Apalutamide may help fight prostate cancer by blocking the use of androgens by the tumor cells. Metastasis-directed targeted radiation therapy uses high energy rays to kill tumor cells and shrink tumors that have spread. This trial may help doctors determine if using PET results to deliver more tailored treatment (i.e., adding apalutamide, with or without targeted radiation therapy, to standard of care treatment) works better than standard of care treatment alone in patients with biochemical recurrence of prostate cancer.

PRIMARY OBJECTIVES:

1. For patients without PET-evidence of extrapelvic metastases, to evaluate whether the addition of enhanced systemic therapy to standard of care (SOC) salvage radiation therapy (RT) could prolong progression-free survival (PFS).

II. For patients with PET-evidence of extrapelvic metastases, to evaluate whether the addition of metastasis-directed RT to enhanced systemic therapy and SOC salvage RT could prolong PFS.

III. To compare overall quality of life, measured by Functional Assessment of Cancer Therapy - Prostate (FACT-P) total score, at 6 months between the two sets of treatment arms (A with B and C with D). (QUALITY OF LIFE [QOL] OBJECTIVE)

SECONDARY OBJECTIVES:

1. To evaluate overall survival in each arm. II. To evaluate event-free survival in each arm. III. To evaluate time to prostate-specific antigen (PSA) progression in each arm.

IV. To assess the incidence of adverse events with the addition of enhanced systemic therapy in patients without PET-evidence of extrapelvic metastases.

1. To assess the incidence of adverse events with local ablative metastasis-directed RT for PET-positive metastatic disease in patients with PET-evidence of extrapelvic metastases.

VI. To estimate the detection rate of PET at the patient and regional level, and to evaluate its concordance with the follow-up Food and Drug Administration (FDA)-approved conventional imaging modalities (CIM) (as available) considered standard-of-care per institution, including computed tomography (CT), bone scintigraphy, magnetic resonance imaging (MRI) and PET imaging.

VII. To determine the distribution of PET-positive lesions among anatomic sites (prostate fossa, intrapelvic soft tissue/lymph node, extrapelvic soft tissue/lymph node, and bone metastases) in patients with post-radical prostatectomy (RP) biochemical recurrence (BCR), correlated with PSA (level, doubling time, velocity) and other relevant clinical parameters.

VIII. To compare the change in overall QOL, measured by FACT-P total score, from baseline to 6 months between the two sets of treatment arms (A with B and C with D). (QOL OBJECTIVE) IX. To compare patient-reported fatigue (Functional Assessment of Chronic Illness Therapy [FACIT]-Fatigue scores) at 6 months between the two sets of treatment arms (A with B and C with D). (QOL OBJECTIVE) X. To compare patient-reported overall QOL (FACT-P scores), fatigue (FACIT-Fatigue scores) and pain interference (patient reported outcomes measurement information system [PROMIS] Pain Interference Short Form 4a) between the two sets of treatment arms (A with B and C with D) at the time of disease progression. (QOL OBJECTIVE)

EXPLORATORY OBJECTIVES:

I.To determine the value of repeat PET (PET2) at time of second PSA progression, clinical concern for progression, or 12 months after completion of enhanced systemic therapy, whichever comes first to assess response to therapy (enhanced systemic therapy +/- focal RT and/or androgen deprivation therapy [ADT]) compared to available standard response assessments (PSA and conventional imaging modalities [CIM]).

II. To compare cognitive function, measured by FACT - cognitive function (Cog) peritoneal cancer index (PCI) and total scores, between the three treatment arms receiving enhanced systemic treatment with ADT and apalutamide (Arms B, C, and D) and antiandrogen therapy (ADT) alone (Arm A) at 6 and 12 month. (QOL OBJECTIVE) III. To compare the change in cognitive function, measured by change in FACT-Cog PCI and total scores, from baseline to 6 and baseline to 12 months, between the three treatment arms receiving enhanced systemic treatment with ADT and apalutamide (Arms B, C, and D) and ADT alone (Arm A) at 6 and 12 months. (QOL OBJECTIVE) IV. To characterize longitudinal change in cognitive function between baseline and 24 months in patients with prostate cancer receiving treatment for biochemical recurrence (BCR) and define clinical and disease related characteristics associated with greater cognitive change by the FACT-Cog PCI and total scores. (QOL OBJECTIVE)

OUTLINE:

STEP 0: Patients undergo SOC PET/CT or PET/MR scan at baseline. Patients randomized to Arms C or D and receiving fluciclovine F18 intravenously (IV) undergo a repeat PET2 at time of PSA progression or clinical concerns for progression or 12 months after completion of enhanced systemic therapy, whichever occurs first. Patients in Arm C or D using another tracer for PET1 do not undergo PET2.

STEP 1: Patients are randomized to 1 of 4 arms based on results of fluciclovine F18 PET/CT or PET/MR in Step 0.

ARM A (PET NEGATIVE FOR EXTRA PELVIC-METASTASES): Patients undergo SOC external beam radiation therapy (EBRT) for 6 months. Patients also receive goserelin acetate subcutaneously (SC), leuprolide acetate intramuscularly (IM), triptorelin IM, relugolix orally (PO), or degarelix SC for 6 months starting up to 3 months prior to EBRT but no later than 7 days after start of EBRT. All treatment continues for 6 months in the absence of disease progression or unacceptable toxicity.

ARM B (PET NEGATIVE FOR EXTRA PELVIC-METASTASES): Patients undergo SOC EBRT and receive goserelin acetate SC, leuprolide acetate IM, triptorelin IM, relugolix PO, or degarelix SC as in Arm A. Patients also receive apalutamide PO once daily (QD) for 6 months in the absence of disease progression or unacceptable toxicity.

ARM C: (PET POSITIVE FOR EXTRA PELVIC-METASTASES): Patients undergo SOC EBRT and receive goserelin acetate SC, leuprolide acetate IM, triptorelin IM, relugolix PO, or degarelix SC as in Arm A. Patients also receive apalutamide PO QD as in Arm B.

ARM D (PET POSITIVE FOR EXTRA PELVIC-METASTASES): Patients undergo SOC EBRT and receive goserelin acetate SC, leuprolide acetate IM, triptorelin IM, relugolix PO, or degarelix SC as in Arm A and apalutamide PO QD as in Arm B. Patients also undergo stereotactic body radiation therapy (SBRT) or 3-dimensional (3D) conformal radiation therapy (CRT), intensity-modulated radiation therapy (IMRT) (including volume modulated arc therapy [VMAT]), and intensity-modulated proton therapy (IMPT) over 3-10 fractions in the absence of disease progression or unacceptable toxicity.

After completion of study treatment, patients are followed up every 3 months for the first 2 years, every 6 months for years 3-5, and then annually for years 6-10.