GI-102 (CD80-IgG4 Fc-IL2v3) in Combination With Pasritamig in Patients With Metastatic Castration-resistant Prostate Cancer (mCRPC) (JET-201)

Participants receive GI-102 in combination with pasritamig during the Safety run-in phase. Dose escalation is guided by a Bayesian Optimal Interval (BOIN) design.

Drug: GI-102 · Drug: Pasritamig

Participants receive GI-102 in combination with pasritamig during the Safety run-in phase. Dose escalation is guided by a Bayesian Optimal Interval (BOIN) design.

Drug: GI-102 · Drug: Pasritamig

Participants enrolled in the Expansion phase will receive the combination recommended Phase 2 regimen (cRP2R) of GI-102 and pasritamig, determined based on the safety and dose-escalation results from the Safety run-in phase.

Drug: GI-102 · Drug: Pasritamig

GI-102 will be administered in accordance with the procedures specified in the study protocol.

Pasritamig will be administered in accordance with the procedures specified in the study protocol.

Plazo: From Day -14 to Cycle 1 Day 22 (35 days)

A DLT is defined as a clinically significant AE (classified according to the NCI CTCAE version 6.0) or significant laboratory abnormality that occur during the DLT assessment periods, and is considered by the Investigator to be related to the study drug(s).

Plazo: Up to 2 years

An adverse event (AE) is any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a pharmaceutical product, whether or not considered related to the pharmaceutical product. Preexisting conditions which worsen during a study are also considered as AEs. All AE events will be graded according to National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) version 6.0.

Plazo: Up to 2 years

PSA response rate is defined as the percentage of participants with a decline of PSA of 50% or more from baseline.

Plazo: Up to 2 years

PSA response rate is defined as the percentage of participants with a decline of PSA of 50% (or 90%) or more from baseline.

Plazo: Up to 2 years

Radiographic PFS is defined as the time from the date of first dose of any study treatment until the date of radiographic disease progression or death, whichever comes first.

Plazo: Up to 2 years

Time to PSA progression, defined as the time from baseline to the first date of documented PSA progression per PCWG3 criteria.

Plazo: Up to 2 years

Among participants with measurable disease, ORR is defined as the percentage of participants who achieve a partial response (PR) or complete response (CR) according to RECIST v1.1.

Plazo: Up to 2 years

Among participants with measurable disease who achieve a CR or PR, DoR is defined as the time from the first documented CR or PR until the first documented disease progression according to RECIST v1.1 or death from any cause, whichever occurs first.

Plazo: Up to 2 years

Among participants with measurable disease, DCR is defined as the percentage of participants who achieve a CR, PR, or stable disease (SD) according to RECIST v1.1.

Plazo: Up to 2 years

An adverse event (AE) is any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a pharmaceutical product, whether or not considered related to the pharmaceutical product. Preexisting conditions which worsen during a study are also considered as AEs. All AE events will be graded according to National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) version 6.0.

Plazo: Up to 2 years

Plasma concentrations of GI-102 will be measured at specified time points following administration of GI-102 in combination with pasritamig to determine the maximum observed plasma concentration (Cmax).

Plazo: Up to 2 years

Plasma concentrations of GI-102 will be measured at specified time points following administration of GI-102 in combination with pasritamig to determine the terminal half-life (T1/2) of GI-102.

Plazo: Up to 2 years

Plasma concentrations of GI-102 will be measured at specified time points following administration of GI-102 in combination with pasritamig to determine the area under the plasma concentration-time curve (AUC) of GI-102.

Plazo: Up to 2 years

Immune cell populations and their changes following study treatment will be assessed in peripheral blood using flow cytometry.

Plazo: Up to 2 years

ORR is defined as the percentage of participants who achieve a partial response (PR) or complete response (CR) according to the iRECIST criteria.

Plazo: Up to 2 years

Overall survival (OS) is defined as the time from the first dose of study treatment to death from any cause.

Plazo: Up to 2 years

Serum samples will be analyzed using a validated assay to determine the incidence of anti-GI-102 antibodies (ADA).

Plazo: Up to 2 years

Serum samples that are positive for anti-GI-102 antibodies (ADA) will be further analyzed using a validated assay to determine the incidence of neutralizing antibodies (Nab).

A Phase 1b/2, Open-label, Multi-center Study to Evaluate the Anti-cancer Activity, Safety and Tolerability of GI-102 (CD80-IgG4 Fc-IL2v3) in Combination With Pasritamig [T-CELL-Redirecting Agent Targeting Human Kallikrein 2 (KLK2)] in Patients With Metastatic Castration-resistant Prostate Cancer (mCRPC) Who Progressed on Previous Novel Hormonal Therapy (NHT) (JET-201)