TEAD Inhibitors for Mesothelioma

TEAD Inhibitors for Mesothelioma
At a Glance
Drug class	YAP/TEAD (Hippo-pathway) inhibitors
FDA status	Investigational — none approved
Lead agent	VT3989 (Vivace Therapeutics)
Best phase 1/2 signal	32% response rate (n=22, optimized dose + UACR threshold)
Molecular target	NF2 / Hippo-pathway–altered tumors
Phase 3	Registered September 2026 (NCT07824986); not yet recruiting
Discontinued programs	IK-930 (2024), IAG933 (2025)

Executive Summary

TEAD inhibitors are a new class of investigational targeted drugs that block the final step of the Hippo signaling pathway, a growth-control circuit that is abnormally active in many mesotheliomas. They are among the most distinctive drug targets in mesothelioma because the disease so frequently carries loss of the NF2 gene and related Hippo-pathway defects, which switch this pathway on. No TEAD inhibitor is approved by the U.S. Food and Drug Administration (FDA) for mesothelioma or any other cancer — every agent in this class remains experimental and available only through clinical trials.

The most advanced agent is VT3989, developed by Vivace Therapeutics. In a phase 1/2 trial published in Nature Medicine in 2025, VT3989 produced an objective response rate of 32% and a disease control rate of 86% in a group of 22 heavily pretreated mesothelioma patients selected for both clinically optimized dosing and a urine albumin-to-creatinine ratio (UACR) threshold, with a median progression-free survival of 40 weeks (about 9 months) as reported from the ESMO 2025 presentation; the Nature Medicine paper reports 10 months. The FDA granted VT3989 Orphan Drug and Fast Track designations in 2025. A phase 3 trial comparing VT3989 with investigator's-choice chemotherapy (gemcitabine or vinorelbine) in previously treated epithelioid pleural mesothelioma, with overall survival as its primary endpoint, was registered in September 2026 (NCT07824986); as of October 2026 it is not yet recruiting. These are early-phase results in a small cohort; they signal activity but do not yet prove a survival benefit, which the phase 3 trial is designed to test.

VT3989 is the most advanced TEAD inhibitor program in mesothelioma. Two other agents that reached the clinic were discontinued: IK-930 (Ikena Oncology) in 2024, after a review of clinical data, available resources and the company's strategic priorities, and IAG933 (Novartis) in 2025, which ApexOnco reported was owing to lack of tolerability and efficacy. Another agent, BPI-460372, reported first-in-human results in 2026 from a solid-tumor study in which 15 of 28 patients had mesothelioma. That history is part of why TEAD is regarded as a difficult but important target — and why VT3989's durable responses have drawn attention. Patients interested in TEAD-directed therapy should discuss molecular testing and clinical-trial eligibility with their oncology care team.

At-a-Glance

TEAD inhibitors in mesothelioma at a glance:

• Investigational class — TEAD inhibitors block YAP/TAZ–TEAD, the endpoint of the Hippo pathway. None is FDA-approved; the most advanced, VT3989, is in a phase 3 trial that has not yet begun recruiting.
• Why mesothelioma — roughly 30–40% of pleural mesotheliomas carry inactivating mutations of the NF2 (merlin) tumor-suppressor gene, and alterations in other Hippo-pathway genes such as LATS2 (7–11% of cases) add to that, driving tumor growth through TEAD.
• VT3989 response rate — 32% objective response and 86% disease control at the optimized dose and UACR threshold (n=22) in a phase 1/2 trial.
• Durability — median progression-free survival of 40 weeks (about 9 months; the Nature Medicine paper reports 10 months) in that same optimized-dose/UACR-threshold n=22 group.
• Responses without a detected NF2 mutation — responses occurred whether or not the tumor had a detected NF2 mutation; in the trial paper, responding tumors without a detected mutation had lost merlin, the NF2 protein, on immunohistochemistry.
• Safety — most side effects were mild to moderate; the main class effect is proteinuria (protein in the urine), managed with an intermittent two-weeks-on / two-weeks-off schedule. A 2026 case report also describes visual decline with chorioretinal atrophy in one VT3989-treated patient, changes its authors presumed to be secondary to the drug; they write that it may be important to ensure ophthalmologic monitoring of patients on drugs targeting the Hippo pathway.
• FDA designations — VT3989 holds Orphan Drug (2025) and Fast Track (2025) designations, which can expedite review but are not approvals.
• Phase 3 — a phase 3 trial of VT3989 against investigator's-choice chemotherapy in previously treated epithelioid pleural mesothelioma was registered in September 2026 (NCT07824986), with an estimated start of December 2026.
• Discontinued programs — Ikena's IK-930 (halted 2024) and Novartis's IAG933 (discontinued 2025) show the target's difficulty.
• How to access — TEAD inhibitors are available only in clinical trials; eligibility is checked at trial centers and on ClinicalTrials.gov.

Key Facts

Measure	Finding (Source)
Drug class	YAP/TEAD (Hippo-pathway) inhibitors — investigational
Lead agent	VT3989 — Vivace Therapeutics, phase 1/2 (NCT04665206)
Objective response rate	32% at optimized dose + UACR threshold (7 of 22 patients), phase 1/2, 2025
Disease control rate	86% at optimized dose + UACR threshold (n=22), phase 1/2
Median progression-free survival	40 weeks (about 9 months; 10 months in the Nature Medicine paper) at optimized dose + UACR threshold (n=22)
Grade 3–4 treatment-related events	Not specified in the published abstract; overall toxicity described as mostly grade 1–2 (n=172)
Reported ocular adverse event	Chorioretinal atrophy, 1 case report, resembling TEAD1 loss-of-function phenotype (JAMA Ophthalmol, 2026)
Molecular target population	NF2 inactivation in ~30–40% of pleural mesothelioma; LATS2 alterations in 7–11%
FDA designations	Orphan Drug (2025) + Fast Track (2025) — not an approval
Phase 3 status	Registered September 2026 (NCT07824986); not yet recruiting
Discontinued agents	IK-930 (Ikena, 2024); IAG933 (Novartis, 2025)

What Is a TEAD Inhibitor?

A TEAD inhibitor is a targeted cancer drug that shuts down TEAD (TEA-domain transcription factors), the proteins that carry out the final instructions of the Hippo signaling pathway. Under normal conditions, the Hippo pathway acts as a brake on cell growth. When that brake is removed — most commonly through loss of the NF2 gene — two partner proteins called YAP and TAZ move into the cell nucleus, bind to TEAD, and switch on genes that drive cell survival, invasion, and proliferation. TEAD inhibitors are designed to interrupt that switch, cutting off the growth signal at its source.

There are two main chemical strategies. VT3989 is an auto-palmitoylation inhibitor: it blocks a fatty-acid modification that TEAD needs in order to work, effectively disabling the protein. Other agents, such as the discontinued IAG933, instead tried to physically pry apart the YAP/TAZ–TEAD connection (a protein–protein-interaction, or PPI, inhibitor). Both approaches aim at the same endpoint but differ in how they get there, and those differences have mattered for how well each drug was tolerated.

It is important to be precise about what these drugs are and are not. TEAD inhibitors are investigational — none has been approved by the FDA for mesothelioma or any other cancer, and they are available only through clinical trials. They are also not a response to what causes mesothelioma. Asbestos exposure remains the established cause of the disease; the Hippo-pathway changes these drugs target are alterations that arise within the tumor after it has formed, and they represent a treatment opportunity rather than an explanation of how the cancer began. For more on the molecular changes found in mesothelioma tumors, see Mesothelioma Molecular and Genetic Testing.

How Does the Hippo Pathway Drive Mesothelioma?

The Hippo pathway is one of the most frequently disrupted growth-control circuits in mesothelioma, which is what makes it such an attractive drug target. Its central brake is a protein called merlin, encoded by the NF2 gene. When merlin is working, it helps keep the pathway "on," which in turn keeps YAP and TAZ out of the nucleus and cell growth in check. When NF2 is lost or mutated, the brake fails, YAP/TAZ flood into the nucleus, and they team up with TEAD to drive relentless tumor growth.

These defects are strikingly common in mesothelioma. Somatic NF2 mutation is found in roughly 30–40% of pleural mesotheliomas, and LATS2 alterations have been observed in 7–11% of mesothelioma cases; the review's authors add that the overall frequency of NF2 and Hippo-pathway abnormalities may be slightly higher than previously reported. That means a substantial share of mesothelioma patients could, in principle, have tumors dependent on this pathway.

Crucially, these are somatic alterations — changes acquired by the tumor cells themselves, not inherited traits and not an alternative cause of the disease. They sit alongside other well-documented molecular features of mesothelioma such as BAP1 and CDKN2A loss. Readers can compare these targets on the BAP1 gene mutation page and in the overview of histological subtypes of mesothelioma. Because Hippo-pathway disruption is so widespread in the disease, a drug that can safely block TEAD has long been viewed as a potentially high-impact addition to mesothelioma treatment — if the target could be drugged without unacceptable side effects.

What Did the VT3989 Trial Show?

VT3989 is the first TEAD inhibitor to produce peer-reviewed clinical evidence of activity in mesothelioma. The pivotal dataset comes from an open-label phase 1/2 dose-escalation and expansion study (NCT04665206) that enrolled 172 patients across U.S. and Australian sites, including MD Anderson Cancer Center and the University of California, San Francisco. Of those patients, 135 (about 79%) had mesothelioma. The results were published in Nature Medicine in 2025 and presented at the 2025 European Society for Medical Oncology (ESMO) Congress.

The most informative data come from the 22 mesothelioma patients selected on two criteria: the clinically optimized dose and schedule — 100 mg once daily on an intermittent two-weeks-on, two-weeks-off cycle — and a urine albumin-to-creatinine ratio (UACR) threshold. In that group, the objective response rate was 32% (7 partial responses) and the disease control rate was 86%, with a median progression-free survival of 40 weeks (95% CI 23 weeks to not evaluable), about 9 months, as reported from the ESMO 2025 presentation; the Nature Medicine paper reports 10 months. In a broader group of 47 mesothelioma patients treated at optimized dose levels alone (no UACR restriction), the response rate was 26%. These are encouraging early numbers, but they come from a small, single-arm, early-phase study rather than a randomized comparison.

The safety profile was a central part of the story. VT3989 showed mostly grade 1–2 toxicities across the full 172-patient population, with just 3.5% discontinuing because of side effects. The signature toxicity was proteinuria (protein leaking into the urine), a known class effect of TEAD inhibitors, which proved reversible with dose adjustment and did not cause lasting kidney damage. The intermittent two-on/two-off schedule was specifically designed to manage this effect while preserving activity — a design choice that distinguishes VT3989 from competitors that used continuous daily dosing. Overall survival data have not yet been reported; overall survival is the primary endpoint of the registered phase 3 trial (NCT07824986). All of these findings remain investigational; VT3989 is not an approved or established treatment.

A 2026 case report in JAMA Ophthalmology — published after the Nature Medicine safety data above and not reflected in it — describes a second concern. A woman in her 50s with metastatic mesothelioma developed visual decline and peripapillary retinal-pigment-epithelium atrophy after five cycles of VT3989, in a pattern resembling Sveinsson chorioretinal atrophy (helicoid peripapillary chorioretinal degeneration), a rare inherited condition caused by loss-of-function mutations in TEAD1 itself. Because the injury mirrors the phenotype of losing the drug's own molecular target, the authors read it as an on-target, mechanism-based effect — a potential class concern for TEAD inhibitors generally, not an idiosyncratic reaction to VT3989 specifically — and recommend ophthalmologic monitoring for patients on Hippo-pathway-targeted drugs.

Which TEAD Inhibitors Have Been Tested in Mesothelioma?

At least six TEAD inhibitors have reached clinical trials that enroll patients with mesothelioma, and the diverging fates of VT3989, IAG933 and IK-930 illustrate why the target has been considered both promising and difficult.

VT3989 (Vivace Therapeutics) is the most advanced program. It is a pan-TEAD auto-palmitoylation inhibitor, and — as described above — it produced durable responses and a manageable safety profile in its phase 1/2 trial, earning FDA Orphan Drug and Fast Track designations. Its phase 3 trial (NCT07824986) was registered in September 2026.

IAG933 (Novartis) was the most advanced competitor and used a different mechanism — a YAP/TAZ–TEAD protein–protein-interaction inhibitor given as continuous daily dosing. It was tested in a first-in-human phase 1 study (NCT04857372) in mesothelioma and other solid tumors. Novartis discontinued the program in 2025: the asset disappeared from its pipeline in its third-quarter earnings presentation, and ApexOnco reported the discontinuation was owing to lack of tolerability and efficacy.

IK-930 (Ikena Oncology) was a TEAD1-selective inhibitor evaluated in a phase 1 trial (NCT05228015). Ikena discontinued the program in May 2024, citing a review of clinical data to date, available resources and the company's strategic priorities, and continued developing another candidate, IK-595. The registry lists the trial as terminated for "sponsor strategic reasons."

BPI-460372 (Betta Pharmaceuticals) is a covalent inhibitor of TEAD palmitoylation. Its first-in-human phase Ia study (NCT05789602) enrolled 28 patients with advanced solid tumors who had progressed after standard therapy or had no standard option, and 15 of them (53.6%) had malignant mesothelioma.

The one confirmed partial response in the study was in a 40-year-old man with pleural mesothelioma treated at 120 mg twice daily. Across all 28 patients, the disease control rate was 64.3% and median progression-free survival was 5.6 months; these figures cover all 28 patients, not the mesothelioma group alone.

No dose-limiting toxicities were observed and the maximum tolerated dose was not reached. Once-daily escalation stopped at 240 mg because of absorption saturation. For the twice-daily schedule, the authors give two reasons for not going past 120 mg: steady-state exposure rose only about 9% from 80 mg to 120 mg twice daily, and further escalation was discontinued because of grade 3 cardiac adverse events.

Treatment-related cardiac adverse events occurred in 50.0% of patients, with grade 3 or higher events in 21.4% and no fatal cardiac events. The authors write that these findings raise the possibility that cardiac toxicity is an on-target effect of TEAD inhibition. Proteinuria was the most common treatment-related adverse event (46.4%), and one treatment-related death, from an abdominal infection, occurred. As of October 2026, ClinicalTrials.gov lists the study as recruiting, with an estimated enrollment of 82.

SW-682 (SpringWorks Therapeutics) is a small-molecule TEAD inhibitor. Its phase 1 study (NCT06251310), sponsored by SpringWorks, a healthcare company of Merck KGaA, enrolls patients with advanced solid tumors and malignant mesothelioma. ISM6331 (InSilico Medicine) is a TEAD inhibitor in a phase 1/2 study (NCT06566079) of patients with advanced or metastatic mesothelioma and other advanced solid tumors. As of October 2026, ClinicalTrials.gov lists both studies as recruiting.

The contrast points to two apparent advantages for VT3989: a pan-TEAD palmitoylation mechanism rather than a paralog-selective or PPI approach, and an intermittent dosing schedule that keeps the class-effect proteinuria in check. None of this guarantees success — a single-arm phase 1/2 signal is not a randomized survival result — but it explains why VT3989 is the program the field is now watching most closely.

Who Might Be Eligible for TEAD Inhibitor Trials?

Because Hippo-pathway disruption is so common in mesothelioma, a broad range of patients could potentially be candidates for TEAD-directed trials — but eligibility is determined by each trial's specific criteria, not by a single test. In the VT3989 study, responses occurred whether or not the tumor had a detected NF2 mutation, and responding tumors without a detected mutation had lost merlin, the protein NF2 encodes.

That said, molecular testing of the tumor is increasingly valuable in mesothelioma care, both for understanding a tumor's biology and for matching patients to appropriate trials. Patients considering a TEAD inhibitor trial may benefit from having NF2 and broader Hippo-pathway status assessed as part of comprehensive genomic testing. The pages on molecular and genetic testing and mesothelioma biomarkers explain how this testing works and where it fits in the diagnostic process.

TEAD inhibitor trials generally focus on patients whose disease has progressed after standard therapy — typically after platinum-based chemotherapy and immune checkpoint inhibitors. That places these drugs in the later-line setting, where new options are most urgently needed. How targeted therapies like TEAD inhibitors fit into the broader treatment sequence is covered in latest treatment advances for mesothelioma and immunotherapy for mesothelioma.

How Do Patients Access TEAD Inhibitor Trials?

Because no TEAD inhibitor is FDA-approved, the only way to receive one is through a clinical trial. The VT3989 phase 1/2 study (NCT04665206) has enrolled at major cancer centers including MD Anderson and UCSF. Its phase 3 trial (NCT07824986) is registered but not yet recruiting. The most reliable, up-to-date source for open trials, locations, and eligibility criteria is the U.S. National Library of Medicine's registry at ClinicalTrials.gov, which lists each trial by its NCT number.

Patients interested in a TEAD inhibitor trial should start by discussing it with their treating oncologist, who can assess whether a trial is medically appropriate and help coordinate referral to a participating center. A specialized mesothelioma treatment center is often the best point of entry, because these centers are more likely to be trial sites and to have the molecular-testing infrastructure that trials require. General guidance on finding and evaluating trials is available on the mesothelioma clinical trials page. As with any investigational therapy, the decision to enroll should be made together with a qualified care team, weighing the potential benefits and the uncertainties that come with early-phase treatment.

Frequently Asked Questions

Is VT3989 approved by the FDA? No. VT3989 is investigational and available only through clinical trials. It holds FDA Orphan Drug and Fast Track designations, which can help speed the review process, but neither is an approval. Its phase 3 trial (NCT07824986) was registered in September 2026 and is not yet recruiting.

What is the Hippo pathway, and why does it matter in mesothelioma? The Hippo pathway is a growth-control system that normally limits cell division. In many mesotheliomas it is disrupted — most often by loss of the NF2 gene — which allows the proteins YAP and TAZ to partner with TEAD and drive tumor growth. TEAD inhibitors are designed to block that final step.

How well does VT3989 work? In a phase 1/2 trial, VT3989 produced a 32% response rate and 86% disease control rate at the optimized dose and UACR threshold in 22 mesothelioma patients, with median progression-free survival of 40 weeks (about 9 months; the Nature Medicine paper reports 10 months). These are promising early results in a small group; they demonstrate activity but do not yet prove a survival benefit, which the phase 3 trial will test.

Do I need an NF2 mutation to be eligible? Not necessarily. In the VT3989 trial, responses occurred whether or not the tumor had a detected NF2 mutation, although responding tumors without a detected mutation had lost merlin, the NF2 protein. Molecular testing is still valuable for understanding your tumor and matching you to trials.

What are the side effects of TEAD inhibitors? The main class effect is proteinuria (protein in the urine). In the VT3989 trial most side effects were mild to moderate, and the proteinuria was reversible with dose adjustment. An intermittent two-weeks-on / two-weeks-off schedule is used to manage it. Separately, a 2026 case report described visual decline with chorioretinal atrophy in one patient after five treatment cycles, resembling a mild form of a rare inherited retinal condition caused by loss-of-function variants in TEAD1; the report's authors write that it may be important to ensure ophthalmologic monitoring of patients on drugs targeting the Hippo pathway.

What happened to the other TEAD inhibitors? Two that reached the clinic were discontinued. Ikena discontinued IK-930 in 2024, citing a review of clinical data, available resources and its strategic priorities. Novartis discontinued IAG933 in 2025; ApexOnco reported the reason as lack of tolerability and efficacy. VT3989 is the most advanced TEAD inhibitor in mesothelioma development. Another agent, BPI-460372, is in an early phase Ia study that includes mesothelioma patients.

How can I find a TEAD inhibitor trial? Search ClinicalTrials.gov by NCT number (the VT3989 study is NCT04665206) and discuss options with your oncologist. Specialized mesothelioma centers are the most likely trial sites. See the clinical trials page for guidance.

Quick Statistics

• 0 — TEAD inhibitors FDA-approved for mesothelioma (all investigational).
• 32% — VT3989 objective response rate at the optimized dose + UACR threshold (n=22), phase 1/2.
• 86% — VT3989 disease control rate at the optimized dose + UACR threshold (n=22).
• 40 weeks — median progression-free survival at the optimized dose + UACR threshold (n=22).
• 172 — total patients in the VT3989 phase 1/2 trial; 135 had mesothelioma.
• 1 — case report of visual decline with chorioretinal atrophy (resembling a mild form of Sveinsson chorioretinal atrophy) after VT3989; its authors suggest ophthalmologic monitoring on Hippo-pathway drugs (JAMA Ophthalmol, 2026).
• 30–40% — pleural mesotheliomas with NF2 inactivation; LATS2 alterations in 7–11% of mesothelioma cases.
• 2 — TEAD inhibitor programs discontinued in mesothelioma (IK-930, IAG933).
• 350 — estimated enrollment of VT3989's phase 3 trial (NCT07824986), registered September 2026.

External Links

• Danziger & De Llano — Mesothelioma Treatment Overview — plain-language guide to current and emerging mesothelioma treatment options
• Mesothelioma Lawyer Center — treatment, diagnosis, and clinical-trial background for patients and families
• Mesothelioma.net — patient resources on treatment, second opinions, and specialist centers
• ClinicalTrials.gov — VT3989 Study (NCT04665206) — official registry listing with locations and eligibility criteria

Related Pages

• Mesothelioma Molecular and Genetic Testing
• BAP1 Gene Mutation in Mesothelioma
• Latest Treatment Advances for Mesothelioma
• Immunotherapy for Mesothelioma
• Clinical Trials for Mesothelioma
• Histological Subtypes of Mesothelioma