# PROSPECT

Source: https://onco.cc/trials/prospect-prostvac/  
OnCo record `prospect-prostvac` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

The prostate cancer vaccine that looked like it added eight and a half months of life in a small trial added nothing in a big one.

## Summary

PROSPECT randomised 1,297 men with asymptomatic or minimally symptomatic metastatic castration-resistant prostate cancer to PROSTVAC (432), PROSTVAC with granulocyte-macrophage colony-stimulating factor (432) or placebo (433), with three planned interim analyses.

At the third interim analysis the futility criteria were met and the trial stopped early. Neither active arm affected overall survival: median 34.4 months with PROSTVAC, hazard ratio 1.01 (95 percent confidence interval 0.84 to 1.20, p=0.47); 33.2 months with the granulocyte-macrophage colony-stimulating factor combination, 1.02 (0.86 to 1.22, p=0.59); and 34.3 months with placebo. Patients alive without radiographic progression, pain progression, chemotherapy initiation or death at 6 months were 29.4, 28.0 and 30.3 percent respectively.

Adverse events were similar across arms, injection site reactions in 62 to 72 percent and fatigue in 21 to 24 percent, with arrhythmias the commonest cardiac event at 1.4 to 3.5 percent. No myocarditis or pericarditis was reported and serious treatment-related events occurred in under 1 percent of all patients.

The phase 2 result that justified the trial had reported a median overall survival 8.5 months longer than placebo. In PROSPECT the placebo arm lived 34.3 months, far longer than the phase 2 control, which is the likeliest explanation: the earlier comparison was against an unrepresentatively poor control group.

## Fields

- Kind: Trial
- Status: negative
- Last checked: 2026-09-25
- Also known as: PROSPECT; BNIT-PRV-301; PROSTVAC phase 3
- Registry id: NCT01322490
- Phase: 3
- Setting: Asymptomatic or minimally symptomatic metastatic castration-resistant prostate cancer, stratified by PSA (below or at least 50 ng/mL) and lactate dehydrogenase (below or at least 200 U/L): PROSTVAC, PROSTVAC with granulocyte-macrophage colony-stimulating factor, or placebo, with overall survival as the primary endpoint
- Sponsor: Bavarian Nordic
- Enrolled: 1297
- Result: Median overall survival 34.4 months with PROSTVAC (hazard ratio 1.01), 33.2 months with PROSTVAC and granulocyte-macrophage colony-stimulating factor (1.02) and 34.3 months with placebo; stopped early for futility.
- Outcomes: Overall survival (median): PROSTVAC 34.4 months vs PROSTVAC with granulocyte-macrophage colony-stimulating factor 33.2 months vs Placebo 34.3 months, HR 1.01
- Replication: Sipuleucel-T, the only prostate cancer vaccine ever approved, did extend survival in IMPACT (25.8 against 21.7 months); its guidance in England, NICE TA332, has since been withdrawn because the marketing authorisation was withdrawn.

## Sources

- ClinicalTrials.gov NCT01322490: https://clinicaltrials.gov/study/NCT01322490
- PROSPECT (Journal of Clinical Oncology 2019): https://doi.org/10.1200/JCO.18.02031

## Connected records

- cancers: [Metastatic castration-resistant prostate cancer](https://onco.cc/cancers/prostate-mcrpc/), [Prostate cancer](https://onco.cc/cancers/prostate/)
- technologies: [Off-the-shelf cancer vaccines](https://onco.cc/technologies/shared-antigen-vaccine/)
- drugs: [PROSTVAC](https://onco.cc/drugs/prostvac/)
- companies: [Bavarian Nordic](https://onco.cc/companies/bavarian-nordic/)
- terms: [Castration-resistant prostate cancer (CRPC)](https://onco.cc/terms/castration-resistance/), [Prostate cancer programmes that failed, and what each failure taught](https://onco.cc/terms/prostate-failed-programmes/), [PSA (prostate-specific antigen)](https://onco.cc/terms/psa/)
- trials: [CA184-043](https://onco.cc/trials/ca184-043-ipilimumab/), [IMPACT (sipuleucel-T)](https://onco.cc/trials/impact-sipuleucel-t/)

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