Recruiting
Phase 1

VIR-5500

Sponsor:

Astellas Pharma Global Development, Inc.

Code:

NCT05997615

Conditions

Hormone-refractory Prostate Cancer

Eligibility Criteria

Sex: Male

Age: 18+

Healthy Volunteers: Not accepted

Interventions

VIR-5500

Androgen receptor signaling inhibitor (ARSI)

Study Details

Brief summary:

The study will be conducted in 4 parts and will commence with dose escalation of VIR-5500 as a monotherapy (Part 1), followed by combination escalation (Part 3a), monotherapy dose expansion (Part 2) and combination dose expansion (Part 4a).

  • Part 1 (Monotherapy Dose Escalation): Single-agent VIR-5500 dose escalation
  • Part 2 (Monotherapy Dose Expansion): Single-agent VIR-5500 dose expansion
  • Part 3 (Combination Dose Escalation): VIR-5500 plus another therapeutic agent dose escalation Part 3a (Combination Dose Escalation): VIR-5500 in combination with an androgen receptor signaling inhibitor (ARSI)
  • Part 4 (Combination Dose Expansion): VIR-5500 plus another therapeutic agent dose expansion Part 4a (Combination Dose Expansion): VIR-5500 in combination with an androgen receptor signaling inhibitor (ARSI)

Conditions

Hormone-refractory Prostate Cancer

Study ID

NCT05997615

Start date

Aug 10, 2023

Status verified date

Aug, 2026

Completion date

Sep 29, 2027

Anticipated

Primary completion date

Sep 29, 2027

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: Male

Age: 18+

Healthy Volunteers: Not accepted

Inclusion Criteria:

Applicable to Parts 1 and 2

1. Have metastatic disease, defined by ≥ 1 metastatic lesion that is present on baseline computed tomography (CT), magnetic resonance imaging (MRI), or bone scan imaging
2. Have documented progressive mCRPC based on ≥ 1 of the criteria (per PCWG3)

  • PSA level ≥ 1 ng/mL that has increased on ≥ 2 successive occasions ≥ 1 week apart
  • Nodal or visceral progression as defined by RECIST v1.1 with PCWG3 modifications
  • Appearance of ≥ 2 new lesions in bone scan
3. Have been treated with ≥ 1 second-generation androgen-signaling inhibitor, including abiraterone, apalutamide, darolutamide, and/or enzalutamide
4. Have been treated with ≥ 1 prior taxane regimens (e.g., docetaxel, cabazitaxel)
5. Are deemed unsuitable for standard of care

Applicable to Part 2, 3a and Part 4a,

1. Have metastatic CRPC, defined by ≥ 1 metastatic lesion that is present on baseline CT, MRI, or bone scan imaging that has documented progressive disease (PD) based on ≥ 1 of the following criteria (per PCWG3):

  • PSA level ≥ 1 ng/mL that has increased on ≥ 2 successive occasions ≥ 1 week apart
  • Nodal or visceral progression as defined by RECIST v1.1 with PCWG3 modifications
  • Appearance of ≥2 new lesions in bone scan
2. Participants with metastatic hormone sensitive prostate cancer (mHSPC) or with biochemical recurrent prostate cancer (BRPC) may also participate in select cohorts of this clinical trial.

Exclusion Criteria:

1. Presence of dominant histopathological features representative of sarcomatoid, spindle cell, or neuroendocrine small cell components
2. Has acute or chronic infections
3. Has a concomitant medical or inflammatory condition that may increase the risk of toxicity to VIR-5500 (AMX-500), per the Investigator
4. Has lesions in proximity of vital organs
5. Has known active CNS metastases and/or carcinomatous meningitis The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.

Study Design

Enrollment

437 participants

Anticipated

Allocation

Non randomized

Intervention Model

Sequential

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Part 1: VIR-5500 Monotherapy Dose Escalation

VIR-5500 will be administered as a monotherapy in patients with mCRPC over a 21-day or 28-day cycle

experimental: Part 2: VIR-5500 Monotherapy Dose Expansion

VIR-5500 will be administered as a monotherapy in patients with mCRPC over a 21-day or 28-day cycle

experimental: Part 3a: VIR-5500 in combination with an ARSI for Dose Escalation

VIR-5500 will be administered in combination with ARSI over a 21-day or 28-day cycle

experimental: Part 4a: VIR-5500 in combination with an ARSI for Dose Expansion

VIR-5500 will be administered in combination with ARSI over a 21-day or 28-day cycle

Interventions

VIR-5500

Pharmaceutical form: Solution for infusion Route of administration: Intravenous (IV) infusion

Androgen receptor signaling inhibitor (ARSI)

Oral administration

Primary outcome measure

  • All parts: Incidence of treatment emergent anti-drug antibodies (ADAs) to VIR-5500 [ Time Frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months ]
  • Part 1 and 3a: Incidence of Dose Limiting Toxicities (DLTs) [ Time Frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to Day 21 or Day 28 ]
  • Part 2 and 4a: Prostate-Specific Antigen (PSA) response rate [ Time Frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months ]
  • Part 2 and 4a: Objective Response Rate (ORR) [ Time Frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months ]
  • Part 1 and 3a: Number of participants with treatment-emergent Adverse Events (AEs) [ Time Frame: from the Cycle 1(each cycle is 21 or 28 days), Day 1 up to approximately 48 months ]

Central Contacts and Locations

Central contacts

Locations

Investigational Site Number: 403

Recruiting

Palo Alto, California, United States, 94304

Investigational Site Number: 401

Recruiting

Houston, Texas, United States, 77030

Investigational Site number: 404

Recruiting

Fairfax, Virginia, United States, 22031

Investigational Site Number: 400

Recruiting

Seattle, Washington, United States, 98109

More Information

Sponsor

Astellas Pharma Global Development, Inc.

Last update posted

Aug 24, 2026

Last verified

Aug, 2026

Keywords

  • Prostate Cancer
  • Castration Resistant Prostatic Cancer
  • High-Risk Biochemical Recurrent Prostate Cancer
  • Metastatic Castration-resistant Prostate Cancer (mCRPC)
  • Hormone Sensitive Prostate Cancer (HSPC)
  • Genital Neoplasms, Male
  • Urogenital Neoplasms
  • Neoplasms by Site
  • Neoplasms
  • Genital Diseases, Male
  • Genital Diseases
  • Urogenital Diseases
  • Prostatic Diseases
  • Male Urogenital Diseases
  • Prostatic Neoplasms
  • Prostatic Neoplasms, Castration-Resistant

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Astellas Pharma Global Development, Inc. on 2026-08-24.