Bicalutamide With or Without Enzastaurin in Treating Patients With Prostate Cancer

DISEASE CHARACTERISTICS: * Histologically confirmed prostate cancer * Hormone-sensitive disease, as evidenced by a serum total testosterone level \> 150 ng/dL * No evidence of metastatic disease on physical exam, CT abdomen/pelvis (or MRI), chest x-ray or CT scan and bone scan within 6 weeks prior to randomization * Underwent prior definitive surgery or radiotherapy * Must have evidence of biochemical failure after primary therapy and subsequent progression as determined by 1 of the following: * Prostate-specific antigen (PSA) ≥ 0.4 ng/mL (in case of radical prostatectomy) * PSA rise ≥ 2 ng/mL above the nadir PSA (in case of radiotherapy) * Baseline PSA must be at least 2 ng/mL and no greater than 50 ng/mL * PSA doubling time (PSADT) \< 12 months PATIENT CHARACTERISTICS: * ECOG performance status 0 - 1 * Granulocytes ≥ 1,500/mm\^3 * Platelet count ≥ 75,000/mm\^3 * Serum creatinine normal or creatinine clearance ≥ 60 mL/min * Serum total bilirubin ≤ 1.5 times upper limit of normal (ULN) * Alkaline phosphatase ≤ 2.5 times ULN * SGOT and SGPT \< 2.5 times ULN * PT/INR normal * Fertile patients must use effective barrier contraception during and for at least 3 months after completion of study treatment * No gastrointestinal (GI) tract disease resulting in: inability to take oral medication, malabsorption syndrome, a requirement for IV alimentation, prior surgical procedures affecting absorption, or uncontrolled inflammatory GI disease (e.g., Crohn's, ulcerative colitis) * No history of allergic reactions attributed to compounds of similar chemical or biologic composition to enzastaurin hydrochloride or bicalutamide * No uncontrolled intercurrent illness including, but not limited to, any of the following: * Ongoing or active infection * Symptomatic congestive heart failure * Unstable angina pectoris * Cardiac arrhythmia * Psychiatric illness/social situations that would limit compliance with study requirements * A history of other malignancy is permitted if the patient is predicted to be disease-free for 2 years PRIOR CONCURRENT THERAPY: * See Disease Characteristics * More than 4 weeks since prior salvage therapy with intent to cure (i.e., surgery, radiotherapy, or other local ablative procedures) * More than 4 weeks since prior prophylactic radiotherapy to prevent gynecomastia * More than 1 year since prior therapy modulating testosterone levels (such as luteinizing-hormone releasing-hormone agonists/antagonists and antiandrogens) unless in the neoadjuvant or adjuvant setting * No 5 alpha reductase inhibitors, ketoconazole, megestrol acetate, systemic steroids, or herbal supplements during PSA value collection * At least 14 days since prior enzyme-inducing anti-epileptic drugs (EIAEDs) * Patients who must begin EIAED therapy while on study are allowed to remain * No concurrent combination antiretroviral therapy for HIV-positive patients * No concurrent anticoagulant therapy * Low dosage acetyl salicylic acid ≤ 325 mg/day allowed * No other concurrent investigational agents or anticancer therapy (i.e., chemotherapy, immunotherapy, radiotherapy, surgery for cancer, or experimental medications) * No history of allergic reactions attributed to compounds of similar chemical or biologic composition to enzastaurin or bicalutamide * Prior neoadjuvant and/or adjuvant therapy ≤ 4 weeks prior to randomization (i.e., hormones, chemotherapy, vaccines, or experimental agents) allowed if PSA rise and PSADT were documented after testosterone level was \> 150 ng/dL