Telmisartan in Prostate Cancer

Inclusion Criteria:

• Participants must be ≥18 years of age.

• Participants must be able and willing to provide informed consent or have asurrogate capable of providing same.

• Participants must not require immediate change in SOC treatment, i.e., patients withstable PSA (do not meet PCWG310 criteria for PSA progression), or with rising PSAbut they remain on SOC treatment (defined as having met PCWG3 criteria for PSAprogression, but do not have clinical/radiographic progression and have not metcriteria for an immediate change in therapy based on PSA doubling time) asdetermined by their primary oncologist

• Participants must be receiving or likely to receive one of the following SOC agentsfor PC:

cabazitaxel, docetaxel (alone or plus abiraterone) olaparib, rucaparib, or talazoparib plus enzalutamide

• Participants must have

• ECOG performance status of 0-2

• Adequate hepatic (SCOT ≤3x ULN) and renal function (serum creatinine ≤2.5 orestimated GFR >30 cc/min)

• Standing systolic blood pressure >/= 110mm Hg

• If not on active surveillance, patient mut have castrate level testosterone

• No contraindication to telmisartan, including ACE inhibitor use in the 6 weeks priorto projected telmisartan start on trial

• All participants must have a systolic blood pressure >110 mm Hg during studyenrollment assessment and throughout the study

• If participants are concurrently treated for hypertension, they must be able toallow telmisartan in addition to, or replacing their antihypertensive regimen

• Participants must be able to withstand planned research phlebotomies (Hb >10 gm/dl).

• Participants must have a blood prostate specific antigen > 1 ng/ml at study entryusing the Roche Cobas immunoassay.

• Participants must be able to take or have taken their own blood pressure per thestudy protocol (daily during telmisartan escalation and for two weeks after thefinal escalation and weekly thereafter for the following month and then monthly) ifnormotensive at enrollment.

Exclusion Criteria:

Participants who fall into one of the following categories will NOT be eligible for this study:

• Angiotensin l receptor blocker use currently or within the 30 days prior to day 1,cycle 1.

• Patients with hypertensive urgency or emergency as defined in N Engl J Med. 2019 Nov 7;381(19):1843-1852. doi:10.1056/NEJMep1901117

• Patients who are incarcerated or homeless

• Patients who are receiving PC-specific treatment aside from cabazitaxel, docetaxel,olaparib, rucaparib, abiraterone or talazoparib plus enzalutamide or have plans toundergo the same during the study period, except local irradiation therapy to PClesions.

• Patients on lithium therapy in any form

• Patients who received rituximab or amifostine within 30 days prior to firsttelmisartan dose on this study

• Patients on ramapril

• Patients on digoxin who do not consent to monthly digoxin blood level testing