Therapeutic anti-cancer vaccines: a systematic review of prospective intervention trials for common hematological malignancies.

BACKGROUND

This review comprehensively assesses all prospective trials on anti-cancer vaccines for common hematological malignancies by analyzing trial designs, endpoints, and whether these endpoints are met across these trials.

METHODS

We included onco prospective clinical trials involving therapeutic anti-cancer vaccines for hematological malignancies published up to May 2025. We excluded retrospective cohort studies, case reports, non-research opinion publications, and studies not related to hematological malignancies. Information sources: Embase, MEDLINE, Web of Science Core Collection, and ClinicalTrials.gov. All the included RCTs were assessed for bias using the Cochrane Handbook for Systematic Review of Interventions, version 6.2 and Cochrane risk-of-bias tool. Results were synthesized descriptively, using frequencies (%) and medians (interquartile range [IQR]). The study protocol utilized was recorded in the PROSPERO database (Registration ID. CRD42024504780).

FINDINGS

Out of 2856 studies screened, a total of 187 studies were included. The median sample size was 18 (IQR = 20), and 33/187 (18%) studies were randomized. Most utilized primary endpoints were translational and safety, of which the endpoint was met 65/81 (80%) and 51/74 (69%) of the time, respectively. In 35/187 (19%) of the total studies included, the primary endpoint was a clinical efficacy endpoint (PFS, OS, duration of remission, cancer response) of which, 11/35 (31%) of studies met their clinical primary endpoint. Of the 33 randomized studies, 24 measured a clinical endpoint as their primary endpoint. Besides BCG administration in AML, no vaccine trial met a clinical efficacy endpoint in a randomized trial. There was not a single instance in which a vaccine product demonstrated an improvement in overall survival. The risk of bias assessment for RCTs showed most studies at low or intermediate risk of bias.

INTERPRETATION

This systematic review of all therapeutic anti-cancer vaccine trials in common hematological malignancies shows that although vaccines generally demonstrate immunogenicity, they have mostly failed to show consistent anti-cancer activity. Limitations include a lack of quantitative synthesis due to heterogeneity of assessed interventions, small sample sizes in most studies, and a lack of clear endpoint description in some studies.

FUNDING

None. PROSPERO Registration ID. CRD42024504780.