What is Amgen actually testing in advanced prostate cancer, and what would success look like? According to a ClinicalTrials.gov record updated June 18, 2026, the company has opened a Phase 3 study comparing xaluritamig plus abiraterone against an investigator's choice of standard therapies in men with chemotherapy-naive metastatic castration-resistant prostate cancer — a population clinicians abbreviate as mCRPC. The trial carries the registry identifier NCT07213674 and is listed as recruiting.

The short version is that this trial asks whether adding a newer kind of immunotherapy to an established hormonal drug helps men live longer than today's standard choices do. Xaluritamig is a T-cell engager — think of it as a molecular adapter that grabs a cancer cell with one hand and a patient's own T cell with the other, pulling them together so the immune cell can attack the tumor. Abiraterone is an established oral therapy that suppresses androgen production, cutting off a fuel source for prostate tumors. The trial pairs the two and tests that combination head-to-head against what oncologists would otherwise reach for.

"The primary objective of this study is to compare overall survival (OS) in participants receiving xaluritamig plus abiraterone against investigator's choice (docetaxel, cabazitaxel, or abiraterone)."— ClinicalTrials.gov, source

That single sentence from the record carries most of the design. The comparator is not a placebo — it is an active-comparator arm in which, per the record, "Participants will receive investigator's choice of" abiraterone acetate orally once daily, docetaxel given intravenously every three weeks, or cabazitaxel given intravenously. In plain terms, the control group gets real, currently used prostate-cancer treatment, and the question is whether the xaluritamig combination beats those options on how long patients survive. The experimental arm, the record states, randomizes participants "to receive xaluritamig in combination with abiraterone acetate," with xaluritamig administered intravenously.

What the endpoint and design tell you

The design module lists a randomized, parallel-assignment, open-label trial — masking is recorded as none. Open-label matters to read correctly: it means patients and investigators know which arm a participant is in, which is common when the treatment regimens (an IV T-cell engager versus oral or chemotherapy options) cannot be plausibly blinded. The single primary outcome is overall survival, assessed over a time frame the record gives as "Up to approximately 51 months." Overall survival is the most stringent endpoint in oncology — it counts whether people are alive, not a surrogate like tumor shrinkage — and a 51-month horizon is consistent with the slow event accrual that survival endpoints require.

Estimated enrollment is 750 participants. Eligibility is restricted to males aged 18 years and older, with no upper age limit recorded, and healthy volunteers are not accepted. The single listed condition is metastatic castration-resistant prostate cancer. The "chemotherapy-naive" qualifier in the official title is the other key inclusion detail: the study is enrolling men who have not yet received chemotherapy for their advanced disease, which positions the combination earlier in the treatment sequence than a salvage setting would.

Timeline and where it sits

The status module records a start date of November 28, 2025, a study-first-posted date of October 9, 2025, and an estimated primary completion date of January 7, 2030. The record was last updated and posted on June 18, 2026, and the overall status is recruiting. Because the primary endpoint is overall survival with completion estimated for early 2030, any efficacy readout is years out; what the June 18, 2026 record establishes is the trial's existence, structure, and stated objective.

For readers following the sector, the registry entry is deliberately narrow about what it asserts. It does not claim that xaluritamig plus abiraterone works better than standard therapy — it defines a comparison and the measure that will decide it. The interventions are named precisely: xaluritamig (IV), abiraterone acetate (oral), docetaxel (IV), and cabazitaxel (IV). The comparison is overall survival. The population is chemotherapy-naive mCRPC. Those are the load-bearing facts in the public record.

Why does the modality matter beyond this one trial? T-cell engagers have reshaped parts of blood-cancer treatment, but extending them to solid tumors like prostate cancer has been harder, because solid tumors are denser and less accessible to immune cells than circulating cancers. A Phase 3 overall-survival trial of a T-cell engager in a common solid tumor is therefore a notable data point in that broader effort — not because of any result, which does not yet exist, but because of where the program now sits in development. The record documents a 750-patient, survival-powered Phase 3 study in a public government registry that any reader can consult directly.

It also helps to understand the term "castration-resistant," because it defines who these patients are. Prostate tumors typically depend on androgens to grow, so the first line of treatment lowers those hormones — medically or surgically — to starve the cancer. Castration-resistant disease means the tumor has found ways to keep growing despite those hormone levels being driven down. That is why abiraterone, which blocks an enzyme involved in androgen synthesis even further upstream, is a standard tool in this setting, and why the record uses it both inside the experimental combination and as one of the investigator's-choice control options. The registry does not editorialize on prognosis; it enrolls this defined, treatment-resistant population and measures survival.

The practical takeaway for a generalist reader is simple. Amgen is testing whether its immune-engaging drug, added to an established hormonal therapy, extends life in men with advanced, treatment-resistant prostate cancer compared with the chemotherapy and hormonal options doctors use today. The trial is recruiting, the bar is overall survival, and the answer is several years away — but the structure of the question is now on the public record.