Study of Oral MRT-2359 With Apalutamide in Prostate Cancer

The film gives the main points. The full list below is copied from the registry; the study team makes the final decision.

• Age18 Years to no maximum
• SexMale
• Healthy volunteersNo

You may be able to join if

• Age > 18 years
• A predicted life expectancy of ≥ 3 months and an ECOG performance status ≤ 1
• Have histologically or cytologically confirmed castration-resistant adenocarcinoma of the prostate without small cell histology and with androgen receptor (AR) mutations
• Have not had prior treatment with more than 1 prior taxane-based chemotherapy regimen for castration-resistant prostate cancer
• Have no prior treatment with an AR degrader, opevesostat, or similar therapy
• Has ongoing (chemical or surgical) androgen deprivation with serum testosterone < 50 ng/dL (< 1.7 nM)
• Has received prior treatment with poly(ADP-ribose) polymerase (PARP) inhibitor, if appropriate, or deemed ineligible to receive treatment by the Investigator, or has refused PARP inhibitor treatment
• Has received prior treatment with at least 1 line of ARPi
• Have disease measurable per Prostate Cancer Working Group 4 (PCWG4) criteria, with or without measurable disease by RECIST 1.1
• Be able to provide a tumor biopsy for biomarker analysis during the Screening period
• Have adequate organ function

You cannot join if

• • Have received prior chemotherapy, definitive radiation, or biological cancer therapy within 21 days before the first dose of study treatment or have any AEs that have failed to recover to baseline
• Have received prior therapy with a GSPT1 degrader that was discontinued due to an AE
• Have received prior auto-HCT and have not fully recovered from effects of the last transplant
• Have received allogeneic hematopoietic stem cell transplantation within past 6 months and/or have symptoms of graft-versus-host disease
• Current use of chronic systemic steroid therapy in excess of replacement doses
• Have clinically active central nervous system involvement and/or carcinomatous meningitis
• Have a confirmed history of (noninfectious) pneumonitis that required steroids
• Clinically significant cardiac disease

This is how the treatment is meant to work. Whether it helps, and how safe it is, is what this trial is testing.

GSPT1 MGD MRT-2359. An orally bioavailable selective molecular glue degrader (MGD) of the translational termination factor GSPT1, with potential antineoplastic activity. Upon oral administration, MRT-2359 targets and binds to GSPT1, thereby promoting complex formation between the E3 ubiquitin ligase component cereblon (CRBN) and GSPT1, and inducing GSPT1 degradation in a CRBN- and degron-dependent manner. This downregulates L-MYC and N-MYC, thereby disrupting MYC-driven protein translation and reducing MYC-oncogenic signaling. This inhibits proliferation in MYC-driven tumors. The translation termination factor GSPT1, a G-loop degron-containing protein, plays a key role in protein translation in MYC-driven cancers. NCI Drug Dictionary

apalutamide. A small molecule and androgen receptor (AR) antagonist with potential antineoplastic activity. Apalutamide binds to AR in target tissues thereby preventing androgen-induced receptor activation and facilitating the formation of inactive complexes that cannot be translocated to the nucleus. This prevents binding to and transcription of AR-responsive genes. This ultimately inhibits the expression of genes that regulate prostate cancer cell proliferation and may lead to an inhibition of cell growth in AR-expressing tumor cells. NCI Drug Dictionary

Treatments listed in the registry

• Oral MRT-2359 (Drug): Orally administered tablets of MRT-2359
• Apalutamide (Drug): Orally administered apalutamide

Na · Single Group · masking: None

Main goals

• Assess the efficacy of MRT-2359 combined with apalutamide (14 months)

Other goals

• Further evaluation of the safety and tolerability of MRT-2359 administered orally in combination with apalutamide
• To assess additional measures of the efficacy of MRT-2359 in combination with apalutamide
• To assess additional measures of the efficacy of MRT-2359 in combination with apalutamide
• To assess additional measures of the efficacy of MRT-2359 in combination with apalutamide
• To assess additional measures of the efficacy of MRT-2359 in combination with apalutamide
• To assess additional measures of the efficacy of MRT-2359 in combination with apalutamide
• To assess additional measures of the efficacy of MRT-2359 in combination with apalutamide
• To assess additional measures of the efficacy of MRT-2359 in combination with apalutamide
• To characterize the population pharmacokinetic profile of MRT-2359 in combination with apalutamide
• To characterize the population pharmacokinetic profile of MRT-2359 in combination with apalutamide
• To characterize the population pharmacokinetic profile of MRT-2359 in combination with apalutamide

Planned enrollment: 25 (estimated).

• START Los Angeles, Los Angeles, California
• XCancer Omaha, Omaha, Nebraska
• START New Jersey, East Brunswick, New Jersey
• START Mountain Region, West Valley City, Utah
• University of Washington Medical Center, Seattle, Washington

Site status as of Oct 30, 2026. Check the live record before contacting a site.

• ClinicalTrials.gov NCT07745361
• NCI Drug Dictionary: C190778
• NCI Drug Dictionary: C92574

Registry record reviewed as fetched Oct 30, 2026, last updated by the sponsor Oct 7, 2026. Public record; not medical advice.