Clinical Trials

Inclusion Criteria:

- Presence of SPOP mutations in prostate cancer cells, as indicated by Next Generation
Sequencing (NGS)

- Patients must have measurable disease, defined as at least one lesion that can be
accurately measured in at least one dimension (longest diameter to be recorded for
non-nodal lesions and short axis for nodal lesions) as >= 20 mm (>= 2 cm) by chest
x-ray or as >= 10 mm (>= 1 cm) with CT scan, MRI, or calipers by clinical exam

- Castrate-range testosterone (< 50 ng/dL) after androgen deprivation therapy (ADT) or
orchiectomy

- Prior treatment with second generation anti-androgen (2GAA) and taxane- or
lutetium-based therapy

- Age >= 18 years. Because no dosing or adverse event data are currently available on
the use of M1774 in patients < 18 years of age, children are excluded from this study

- Eastern Cooperative Oncology Group (ECOG) performance status =< 2 (Karnofsky >= 60%)

- Absolute neutrophil count >= 1,500/mcL

- Platelets >= 100,000/mcL

- Total bilirubin =< 1.5 x institutional upper limit of normal (ULN)

- Aspartate aminotransferase (AST)(serum glutamic-oxaloacetic transaminase [SGOT]) and
alanine aminotransferase (ALT)(serum glutamic-pyruvic transaminase [SGPT]) =< 3 x
institutional ULN

- Creatinine =< 1.5 × ULN

- Creatinine clearance >= 50 mL/min

- Creatinine clearance should be measured if estimated glomerular filtration rate
(eGFR) is > 60 mL/min

- Hemoglobin >= 9.0g/dL

- Human immunodeficiency virus (HIV)-infected patients on effective anti-retroviral
therapy with undetectable viral load within 6 months are eligible for this trial

- For patients with evidence of chronic hepatitis B virus (HBV) infection, the HBV viral
load must be undetectable on suppressive therapy, if indicated

- Patients with a history of hepatitis C virus (HCV) infection must have been treated
and cured. For patients with HCV infection who are currently on treatment, they are
eligible if they have an undetectable HCV viral load

- Patients with treated brain metastases are eligible if follow-up brain imaging after
central nervous system (CNS)-directed therapy shows no evidence of progression

- Patients with new or progressive brain metastases (active brain metastases) or
leptomeningeal disease are eligible if the treating physician determines that
immediate CNS specific treatment is not required and is unlikely to be required during
the first cycle of therapy

- Patients with a prior or concurrent malignancy whose natural history or treatment does
not have the potential to interfere with the safety or efficacy assessment of the
investigational regimen are eligible for this trial

- Patients with known history or current symptoms of cardiac disease, or history of
treatment with cardiotoxic agents, should have a clinical risk assessment of cardiac
function using the New York Heart Association Functional Classification. To be
eligible for this trial, patients should be class 2B or better

- The effects of M1774 on the developing human fetus are unknown. For this reason and
because ATR inhibitors may be teratogenic (Musson et al., 2022), women of
child-bearing potential who are partners of men enrolled on this protocol must agree
to use adequate contraception (hormonal or barrier method of birth control;
abstinence) prior to the study, for the duration of study participation, and 6 months
after completion of M1774 administration. Should a woman become pregnant or suspect
she is pregnant while her partner is participating in this study, she should inform
her treating physician immediately. Men enrolled on this study must agree to use
adequate contraception prior to study entry, for the duration of study participation,
and 3 months after completion of M1774 administration

- Ability to understand and the willingness to sign a written informed consent document.
Legally authorized representatives may sign and give informed consent on behalf of
study participants

Exclusion Criteria:

- Patients who have not recovered from adverse events due to prior anti-cancer therapy
(i.e., have residual toxicities > grade 1) with the exception of alopecia

- Patients who are receiving any other investigational agents

- Patients with uncontrolled intercurrent illness

- Patients who cannot discontinue proton pump inhibitors (PPIs). H-2 receptor
antagonists and antacids are allowed

- Patients who cannot discontinue drugs that are strong inhibitors of CYP3A4 or CYP1A2

- Patients who cannot discontinue drugs that are hMATE1 or hMATE2-Ksubstrates

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 6/19/23. Questions regarding updates should be directed to the study team contact.