UV1 Telomerase Vaccine

The UV1 Telomerase Vaccine is an investigational peptide cancer vaccine developed by Ultimovacs ASA that targets human telomerase reverse transcriptase (hTERT), an enzyme expressed in the great majority of human cancers but largely silent in normal adult tissue. In malignant pleural mesothelioma (MPM), UV1 has been tested in combination with the checkpoint inhibitors ipilimumab + nivolumab in the randomized Phase 2 NIPU trial (NCT04300244) as second-line therapy after first-line platinum + pemetrexed. The trial's pre-specified primary endpoint — progression-free survival by blinded independent central review — was not met (hazard ratio 1.01, 80% confidence interval 0.75–1.36, P = 0.979). Secondary readouts (investigator-assessed PFS, confirmed objective response rate, and overall survival) all trended in favour of the UV1 arm but did not reach pre-specified significance. The U.S. Food and Drug Administration granted UV1 + ipilimumab + nivolumab Fast Track designation on February 5, 2024 for unresectable malignant pleural mesothelioma in the first-line setting — a setting in which UV1 has not yet been tested in a randomized trial. A pivotal Phase 3 study is publicly planned but, as of May 28, 2026, has not been registered on ClinicalTrials.gov.

UV1 Telomerase Vaccine
Investigational hTERT Peptide Vaccine
Drug Class	Therapeutic cancer vaccine (long-peptide)
Target Antigen	Human telomerase (hTERT)
Sponsor	Ultimovacs ASA (Oslo, Norway)
Pivotal Trial	NIPU (NCT04300244) — Phase 2, randomized
Combination Partner	Ipilimumab + nivolumab
Setting Tested	Second-line pleural mesothelioma
Primary Endpoint	PFS by BICR — NOT MET (HR 1.01, P = 0.979)
FDA Fast Track	Granted Feb 5, 2024 (first-line MPM)
FDA Orphan Drug	Granted October 2023
FDA Approval	Not approved
Phase 3 Status	Planned; not yet registered

Executive Summary

UV1 is a synthetic long-peptide cancer vaccine built from three peptides derived from the catalytic subunit of human telomerase reverse transcriptase (hTERT). Telomerase is expressed in ≥85% of human cancers — including pleural mesothelioma — and largely silent in normal adult tissue, which makes it an attractive vaccine antigen with limited off-target risk. The peptides are injected intradermally with granulocyte-macrophage colony-stimulating factor (GM-CSF) as adjuvant; antigen-presenting cells process them and present the fragments on MHC class I and II to induce both CD4⁺ and CD8⁺ telomerase-specific T-cell responses.

In mesothelioma, UV1 has been tested in the randomized Phase 2 NIPU trial (NCT04300244), a 118-patient study at sites in Norway, Denmark, Sweden, Spain, and Australia. Patients had inoperable pleural mesothelioma that had progressed after first-line platinum + pemetrexed and were randomized 1:1 to ipilimumab + nivolumab + UV1 versus ipilimumab + nivolumab alone. The pre-specified primary endpoint was progression-free survival by blinded independent central review (BICR). That endpoint was not met: median PFS by BICR was 4.2 months on the UV1 arm versus 4.7 months on control, with hazard ratio 1.01 (80% CI 0.75–1.36, P = 0.979). The published conclusion stated that predefined analyses of response rates were in favour of adding the vaccine, but the trial cannot be characterised as positive on its primary endpoint.

Three points distinguish UV1 from the immunotherapy regimens currently approved in mesothelioma. First, the mechanism is antigen-specific T-cell priming rather than broad checkpoint release — UV1 is intended to give checkpoint inhibition a defined target to act on. Second, the trial that generated the supporting data was second-line, while the FDA Fast Track designation Ultimovacs received in February 2024 is for the first-line setting; no randomized first-line UV1 data yet exist. Third, the Phase 3 program in mesothelioma has been publicly described as planned but has not been registered on ClinicalTrials.gov as of May 28, 2026 — sober context for any timeline question.

UV1 is not a treatment patients can obtain through ordinary clinical channels in 2026. It is an investigational agent available only through the NIPU follow-up program and, potentially, through future registered trials. Patients and clinicians evaluating UV1 in mesothelioma should rely on the NIPU final results paper (PMID 38447379) and any subsequent registered Phase 3 protocol for current evidence.

At-a-Glance

UV1 telomerase vaccine at a glance:

• Class: Synthetic long-peptide cancer vaccine targeting hTERT (telomerase) — administered intradermally with GM-CSF adjuvant.
• Sponsor: Ultimovacs ASA, Oslo, Norway.
• Pivotal trial in mesothelioma: NIPU (NCT04300244) — Phase 2, randomized, open-label, n = 118, second-line pleural mesothelioma, sites in Norway, Denmark, Sweden, Spain, and Australia, PI Åslaug Helland (Oslo University Hospital).
• Combination tested: UV1 plus ipilimumab + nivolumab (the checkpoint backbone) — not pembrolizumab, and not chemotherapy.
• Primary endpoint NOT MET: BICR-determined median PFS 4.2 vs 4.7 months; hazard ratio 1.01 (80% CI 0.75–1.36), P = 0.979.
• Investigator-assessed PFS (secondary): 4.3 vs 2.9 months, HR 0.60 (80% CI 0.45–0.81), P = 0.025 — a directionally positive signal that did not reproduce on central review.
• Confirmed ORR (secondary, BICR): 31% vs 16%, odds ratio 2.44, P = 0.056 — exploratory.
• Overall survival at 17.3-month median follow-up: 15.4 vs 11.1 months, HR 0.73 (80% CI 0.53–1.00), P = 0.197.
• FDA Fast Track granted February 5, 2024 for first-line unresectable MPM — a setting where UV1 has not been tested.
• FDA Orphan Drug granted October 2023; EMA Orphan Drug designation also granted.
• No FDA approval as of May 2026; Phase 3 planned but not yet registered on ClinicalTrials.gov.

Key Facts

Measure	Finding (Source)
Trial Design	NIPU — Phase 2, randomized, open-label, multi-centre, 1:1, n = 118 (NCT04300244, Haakensen et al., Eur J Cancer 2024).
Population	Inoperable pleural mesothelioma progressing after first-line platinum + pemetrexed — i.e., second-line treatment (Haakensen et al., Eur J Cancer 2024).
Regimen Tested	UV1 + ipilimumab + nivolumab (Bristol-Myers Squibb checkpoint backbone) — NOT pembrolizumab (NCT04300244 interventions field).
Primary Endpoint Result	NOT MET. BICR median PFS 4.2 vs 4.7 mo; HR 1.01 (80% CI 0.75–1.36); P = 0.979 (Haakensen et al., Eur J Cancer 2024 — verbatim: "The primary endpoint was not met.").
Investigator-Assessed PFS (Secondary)	4.3 vs 2.9 mo; HR 0.60 (80% CI 0.45–0.81); P = 0.025 — directionally positive but did not reproduce on central review (Haakensen et al., Eur J Cancer 2024).
Confirmed ORR (Secondary, BICR)	31% (UV1) vs 16% (control); OR 2.44 (80% CI 1.35–4.49); P = 0.056 — exploratory (Haakensen et al., Eur J Cancer 2024).
Overall Survival (Secondary)	15.4 vs 11.1 mo at 17.3-mo median follow-up; HR 0.73 (80% CI 0.53–1.00); P = 0.197 (Haakensen et al., Eur J Cancer 2024).
FDA Fast Track Designation	Granted February 5, 2024, for UV1 + ipilimumab + nivolumab in first-line unresectable MPM (Targeted Oncology; Cancer Network).
FDA Orphan Drug Designation	Granted October 2023 (Ultimovacs investor release).
EMA Orphan Drug Designation	Granted (Ultimovacs investor release).
Imaging Biomarker Substudy	PET/CT — higher baseline metabolic tumour volume (MTV) associated with worse OS, multivariate HR 1.35 (95% CI 1.09–1.68), P = 0.007 (Thunold et al., Eur J Nucl Med Mol Imaging 2025).
Phase 3 Status	Publicly planned by sponsor; no Phase 3 NCT number registered on ClinicalTrials.gov as of May 28, 2026 (ClinicalTrials.gov search).

What Is the UV1 Telomerase Vaccine?

UV1 is a therapeutic cancer vaccine — a vaccine intended not to prevent disease, but to teach the immune system of a person who already has cancer to recognise and attack tumour cells. It is built from three synthetic peptides derived from the catalytic subunit of human telomerase reverse transcriptase (hTERT). Each peptide is a "long peptide": long enough that the body's antigen-presenting cells must process it before presenting fragments on both major histocompatibility complex (MHC) class I — which engages CD8⁺ cytotoxic T cells — and MHC class II — which engages CD4⁺ helper T cells. Inducing both arms of the T-cell response is the design intent.

The vaccine is delivered intradermally (just under the skin), with GM-CSF (sargramostim) co-administered as adjuvant. GM-CSF helps recruit and activate dendritic cells at the injection site so they can take up the peptides and migrate to draining lymph nodes, where they prime telomerase-specific T cells. In the NIPU mesothelioma trial, eight intradermal UV1 doses were given over the first roughly three months of treatment, alongside ongoing checkpoint inhibition with ipilimumab + nivolumab.

Why Telomerase as a Target?

Telomerase is the enzyme that maintains the protective caps (telomeres) at the ends of chromosomes. Normal somatic cells in adult tissue largely silence telomerase as part of cellular ageing; in contrast, cancer cells reactivate telomerase to enable the unlimited replication that defines malignancy. Telomerase activity is detectable in approximately 85% or more of human cancers — including pleural mesothelioma. A vaccine that targets a near-universal cancer antigen with limited expression in normal tissue carries a favourable theoretical risk profile for autoimmune off-target effects.

Why Combine UV1 With Checkpoint Inhibition?

The strategic logic of the NIPU regimen is that vaccines and checkpoint inhibitors act on different bottlenecks in the anti-tumour immune response:

• UV1 supplies tumour-specific T cells — antigen priming
• Ipilimumab (anti-CTLA-4) widens the pool of T cells that can be activated in lymph nodes
• Nivolumab (anti-PD-1) prevents T cells from being silenced once they reach the tumour

The hypothesis tested in NIPU was that adding UV1 to a dual checkpoint backbone would yield a deeper or more durable response than checkpoint inhibition alone. The NIPU protocol paper described this as "a well-founded scientific rationale for the combination of a telomerase vaccine and checkpoint inhibition to improve treatment response in MPM patients."

The NIPU Trial

NIPU (NCT04300244) is the trial that anchors essentially everything publicly known about UV1's clinical activity in mesothelioma. Final results were published by Haakensen and colleagues in the European Journal of Cancer in 2024. The full design and outcome detail are summarised in the dedicated NIPU Trial page; the operational features most relevant to understanding the UV1 evidence base are summarised below.

Trial Design Summary

Feature	Detail
Registration	NCT04300244
Phase / Design	Phase 2, randomized, open-label, multi-centre
Sponsor / PI	Oslo University Hospital, Åslaug Helland, MD, PhD; collaborators Ultimovacs ASA and Bristol-Myers Squibb
Sites	Norway, Denmark, Sweden, Spain, Australia
Population	Inoperable malignant pleural mesothelioma progressing after first-line platinum + pemetrexed
Sample Size	118 patients, randomized 1:1
Experimental Arm	Ipilimumab 1 mg/kg every 6 weeks + nivolumab 240 mg every 2 weeks + 8 intradermal UV1 doses over ~3 months
Control Arm	Ipilimumab 1 mg/kg every 6 weeks + nivolumab 240 mg every 2 weeks
Primary Endpoint	PFS by blinded independent central review (BICR), modified RECIST
Powering	69 PFS events to detect HR 0.60 at 80% power, one-sided α = 0.10
Study Start	May 4, 2020
Primary Completion	March 15, 2025

The single most important interpretive detail is the population. NIPU enrolled patients after first-line chemotherapy had failed. Those patients had already passed the disease milestone at which dual immunotherapy with ipilimumab + nivolumab is now approved in many jurisdictions (based on the CheckMate 743 trial). NIPU therefore answered the question "does adding UV1 to dual checkpoint inhibition improve outcomes after first-line chemo has failed" — not "should UV1 be given upfront."

What the Trial Actually Found

Primary Endpoint — Not Met

The pre-specified primary endpoint was progression-free survival as determined by blinded independent central review (BICR) per modified RECIST. Quoting the published abstract verbatim: "The primary endpoint was not met."

• Median PFS by BICR: 4.2 months (95% CI 2.9–9.8) in the UV1 arm versus 4.7 months (95% CI 3.9–7.0) in the control arm
• Hazard ratio for progression or death: HR 1.01 (80% CI 0.75–1.36)
• P = 0.979 — well above any threshold for statistical significance
• Median follow-up at PFS analysis: 12.5 months

By the pre-specified, regulatory-grade analysis, adding UV1 to ipilimumab + nivolumab did not extend progression-free survival.

Secondary and Exploratory Signals

Several secondary outcomes trended in favour of the UV1 arm but did not reach pre-specified significance:

• Investigator-assessed median PFS: 4.3 months (UV1) vs 2.9 months (control); HR 0.60 (80% CI 0.45–0.81), P = 0.025
• Confirmed objective response rate (ORR) by BICR: 31% vs 16%; odds ratio 2.44 (80% CI 1.35–4.49), P = 0.056
• Overall survival at 17.3-month median follow-up: 15.4 months vs 11.1 months; HR 0.73 (80% CI 0.53–1.00), P = 0.197

The published conclusion read: "Predefined analyses of response rates are in favour of adding the vaccine."

Why BICR-PFS and Investigator-PFS Diverged

The discrepancy between BICR-PFS (negative, HR 1.01) and investigator-PFS (positive, HR 0.60) is itself a finding worth surfacing. In NIPU, central radiology review did not reproduce the on-site investigators' progression calls. BICR is the more conservative analysis and the standard against which regulators evaluate the primary endpoint of a randomized trial. When investigator-PFS and BICR-PFS point in different directions, the conservative reading is that the apparent benefit may reflect measurement variability or investigator bias rather than a genuine drug effect. The ORR difference (31% vs 16%), assessed by BICR rather than investigator review, is a more independent — though still exploratory and underpowered — signal.

Imaging Biomarker Substudy

A pre-specified PET/CT substudy reported separately by Thunold and colleagues evaluated 18F-fluorodeoxyglucose imaging at baseline (n = 100) and week 5 (n = 76) in NIPU participants. Higher baseline metabolic tumour volume (MTV) was associated with worse overall survival (multivariate HR 1.35, 95% CI 1.09–1.68, P = 0.007), and early reductions in total lesion glycolysis, SUVmax, and SUVpeak at week 5 correlated with objective response. The substudy supports MTV as a prognostic marker in immunotherapy-treated pleural mesothelioma but does not change the primary trial verdict.

Regulatory Status — and the First-Line / Second-Line Gap

UV1's regulatory standing in mesothelioma has two layers that need to be read together because they cover different settings.

Designation	Date / Status	Setting Specified
FDA Fast Track designation	Granted February 5, 2024	UV1 + ipilimumab + nivolumab — first-line unresectable MPM
FDA Orphan Drug designation	Granted October 2023	Mesothelioma
EMA Orphan Drug designation	Granted (Ultimovacs investor release)	Mesothelioma
FDA approval	Not approved	No Biologics License Application reported as of May 2026

The Fast Track designation accelerates FDA review and communication for drugs intended to treat serious conditions with unmet need. It is not an approval, and it does not endorse efficacy. It does indicate that the agency views first-line MPM as a setting where an effective new therapy would be welcomed.

The interpretive gap that matters: the Fast Track designation specifies the first-line setting, but the only randomized clinical data for UV1 in mesothelioma — the NIPU trial — was conducted in the second-line setting after first-line chemotherapy failed. A randomized first-line evaluation of UV1 in mesothelioma has not yet been conducted. Whether the secondary signals from NIPU (better ORR, longer investigator-PFS, longer OS) would extend to a chemotherapy-naïve, first-line population is an open empirical question that only a properly powered first-line trial can answer.

Phase 3 Outlook

Ultimovacs has publicly indicated intent to pursue a pivotal Phase 3 program for UV1 in mesothelioma. As of May 28, 2026, no Phase 3 protocol for UV1 in mesothelioma is registered on ClinicalTrials.gov. Specifics that would normally accompany a pivotal trial — Phase 3 design, sample size, comparator arm, primary endpoint, enrolment timeline — are not publicly available because no registered protocol exists.

A realistic outlook for the program must also take into account that Ultimovacs' two other Phase 2 UV1 readouts in the same window — INITIUM in melanoma and FOCUS in head-and-neck cancer — both missed their primary endpoints, results widely reported in the oncology trade press. The mesothelioma program is no longer the only UV1 program for which the published Phase 2 evidence is mixed. Patients and clinicians evaluating UV1 should treat any "Phase 3 underway" framing with caution unless it is accompanied by an active NCT number, an enrolling status, and a defined primary endpoint.

Safety

The NIPU final-results abstract did not foreground specific safety findings. The full paper reports an adverse-event profile broadly consistent with the ipilimumab + nivolumab backbone, which carries well-characterised risks of immune-related adverse events affecting skin, gastrointestinal tract, liver, lungs, and endocrine organs.

Across the broader UV1 development programme, the most commonly reported vaccine-specific adverse event has been injection-site reactions — typically Grade 1–2 erythema, induration, or pruritus at the intradermal injection site. No vaccine-specific systemic safety signals have been described in any UV1 Phase 1/2 programme reported to date.

For mesothelioma patients considering enrolment in a future UV1 trial, the practical safety question is whether the addition of UV1 changes the rate or severity of immune-related adverse events from the underlying checkpoint inhibitor backbone — a question best answered by the full NIPU publication and any subsequent Phase 3 safety database, not from the abstract-level data summarised here.

Frequently Asked Questions

Did UV1 work in the NIPU trial?

The pre-specified primary endpoint — progression-free survival by blinded independent central review — was not met (HR 1.01, P = 0.979). Secondary readouts (investigator-assessed PFS, confirmed objective response rate, overall survival) all trended in favour of the UV1 arm but did not reach pre-specified significance. The trial's published conclusion was that "predefined analyses of response rates are in favour of adding the vaccine," but NIPU cannot be characterised as a positive trial on its primary endpoint.

What combination was tested in NIPU?

NIPU tested UV1 plus ipilimumab + nivolumab (the Bristol-Myers Squibb dual checkpoint backbone), versus ipilimumab + nivolumab alone. UV1 was not tested with pembrolizumab, and it was not tested with chemotherapy.

Has the FDA approved UV1 for mesothelioma?

No. As of May 2026, UV1 is not FDA-approved for mesothelioma or any other indication. It holds FDA Fast Track designation (granted February 5, 2024, for the first-line setting) and FDA and EMA Orphan Drug designations, but those are pre-approval regulatory tools — not approvals. No Biologics License Application has been publicly reported.

What is FDA Fast Track designation and why did UV1 receive it?

Fast Track is an FDA mechanism that accelerates communication and review for drugs intended to treat serious conditions with unmet medical need. It typically allows rolling review of a marketing application and more frequent agency meetings. UV1 + ipilimumab + nivolumab received Fast Track designation on February 5, 2024 for unresectable malignant pleural mesothelioma in the first-line setting.

Is there a Phase 3 UV1 trial for mesothelioma?

Not yet. Ultimovacs has publicly stated intent to pursue a pivotal Phase 3 program, but as of May 28, 2026 no Phase 3 protocol is registered on ClinicalTrials.gov for UV1 in mesothelioma. Until a protocol is registered with a comparator, primary endpoint, and enrolment plan, Phase 3 design details cannot be reported reliably.

What were the secondary signals from NIPU and what do they mean?

Investigator-assessed PFS was 4.3 vs 2.9 months (HR 0.60, P = 0.025); confirmed ORR by central review was 31% vs 16% (P = 0.056); overall survival at 17.3-month median follow-up was 15.4 vs 11.1 months (HR 0.73, P = 0.197). These are directionally positive but exploratory — they did not meet pre-specified significance, and the central radiology review did not reproduce the investigator-PFS signal. The honest interpretation is "hypothesis-generating signals on a missed primary endpoint."

How does UV1 work?

UV1 consists of three long peptides derived from human telomerase (hTERT). When injected intradermally with GM-CSF, the peptides are taken up by dendritic cells, processed, and presented to T cells via MHC class I and II. The resulting telomerase-specific CD4⁺ and CD8⁺ T cells can recognise tumour cells that express hTERT — which is most cancers, including pleural mesothelioma. Combined with checkpoint inhibition, the vaccine is intended to give those T cells both a target and freedom from inhibition once they reach the tumour.

Why does the FDA Fast Track cover first-line use if NIPU was a second-line trial?

This is the most important structural question about the UV1 evidence base. The Fast Track designation is for the first-line setting because that is where the sponsor and the agency see unmet need and where a future approval pathway is most plausible. The randomized data, however, come from a second-line trial. A randomized first-line UV1 trial in mesothelioma has not yet been conducted — whether the secondary NIPU signals would extend to a chemotherapy-naïve first-line population is an open question that requires a new trial.

Related Pages

• NIPU Trial — full design and outcome detail for the pivotal Phase 2 trial
• Immunotherapy for Mesothelioma — overview of checkpoint inhibitors and experimental immunotherapies
• Mesothelioma Treatment — standard and emerging treatment options
• Clinical Trials Mesothelioma — current trials enrolling patients
• ATOMIC-Meso Trial — Phase 2-3 pegargiminase in nonepithelioid mesothelioma
• CheckMate 743 Trial — first-line nivolumab + ipilimumab approval study
• Pleural Mesothelioma — disease overview