TTFields Optune Lua

Tumor Treating Fields (TTFields) / Optune Lua for Mesothelioma

Overview

Tumor Treating Fields (TTFields) represent a first-in-class, non-invasive cancer treatment that uses alternating electric fields to disrupt cancer cell division. The NovoTTF-100L system — now branded Optune Lua — became the first FDA-approved mesothelioma treatment in more than 15 years when it received Humanitarian Device Exemption (HDE) approval on May 23, 2019. Approval was based on the phase 2 STELLAR trial (NCT02397928), in which 80 patients with unresectable malignant pleural mesothelioma (MPM) treated with TTFields plus pemetrexed and platinum-based chemotherapy achieved a median overall survival of 18.2 months — compared to a historical control of 12.1 months with chemotherapy alone.

TTFields therapy is delivered continuously via a portable medical device weighing just 1.2 kg (second-generation model) with transducer arrays placed on the patient's torso, with a recommended usage of at least 18 hours per day. Often described as a "fourth modality" in cancer treatment — alongside surgery, radiation, and systemic therapy — TTFields have demonstrated antitumor effects through multiple mechanisms including mitotic spindle disruption, DNA damage repair interference, immune activation, and enhanced chemotherapy sensitivity. The only device-related adverse events are mild-to-moderate skin reactions beneath the arrays, with no additional systemic toxicity beyond what is expected from chemotherapy.

As of 2026, more than 110 U.S. hospitals are certified to offer TTFields for mesothelioma, and the therapy is commercially available in multiple countries including Austria, France, Germany, Israel, Japan, and Switzerland.

TTFields / Optune Lua
Device Name	Optune Lua (NovoTTF-100L / NovoTTF-200T)
Manufacturer	NovoCure Ltd.
FDA Approval	May 23, 2019 (HDE)
Indication	Unresectable, locally advanced or metastatic MPM
Frequency	150 kHz
Pivotal Trial	STELLAR (NCT02397928)
Median OS	18.2 months (vs 12.1 historical)
1-Year Survival	62.2%
Device Weight	1.2 kg (2nd gen)
Daily Usage	≥18 hours/day recommended
Estimated Cost	~$21,000/month
Approved Indications	MPM, GBM (new & recurrent), NSCLC

Key Facts

Key Facts: TTFields / Optune Lua for Mesothelioma

TTFields are low-intensity alternating electric fields (150 kHz for mesothelioma) that disrupt cancer cell division while sparing normal cells The STELLAR trial demonstrated 18.2-month median overall survival in 80 patients with unresectable MPM — a 50% improvement over the 12.1-month historical control with chemotherapy alone FDA granted Humanitarian Device Exemption approval on May 23, 2019 — the first new mesothelioma treatment approved since pemetrexed in 2004 Patients with epithelioid histology achieved median OS of 21.2 months versus 12.1 months for non-epithelioid subtypes The only device-related adverse event is localized skin irritation — 66% grade 1-2 and 5% grade 3 — with no systemic toxicity The second-generation Optune Lua weighs 1.2 kg (down from 2.7 kg) and is worn continuously for at least 18 hours per day More than 110 U.S. hospitals are certified to provide TTFields therapy for mesothelioma TTFields therapy costs approximately $21,000 per month, with NovoCure offering financial assistance programs for qualifying patients Two STELLAR patients have demonstrated exceptional long-term responses — one remaining in remission for over 8 years after treatment NCCN and ASCO guidelines do not prominently feature TTFields for mesothelioma, reflecting the lack of phase 3 randomized controlled trial data Preclinical evidence suggests mesothelioma cells are among the most sensitive to TTFields across all cancer types studied

What Are Tumor Treating Fields?

Tumor Treating Fields (TTFields) are low-intensity (1–3 V/cm), intermediate-frequency (100–300 kHz) alternating electric fields delivered non-invasively to tumors through insulated transducer arrays placed on the skin. The therapy exploits the geometrical shape and electrical properties of dividing cells, making rapidly proliferating cancer cells susceptible to the electric field's effects while sparing most normal, non-dividing cells. For mesothelioma and non-small cell lung cancer (NSCLC), the frequency is set at 150 kHz, while glioblastoma (GBM) uses 200 kHz — the optimal frequency inversely correlates with cell size.

Mechanisms of Cancer Cell Destruction

TTFields exert antitumor effects through multiple complementary mechanisms that have been progressively elucidated over two decades of research:

Mitotic Spindle Disruption: During metaphase, TTFields interfere with the alignment of highly polarized tubulin subunits, preventing proper mitotic spindle assembly. This reduces the ratio of polymerized to total tubulin, leading to cell cycle arrest and aberrant mitosis. The landmark 2015 study by Giladi and colleagues in Scientific Reports demonstrated this effect using live-cell imaging and biochemical analysis.

Dielectrophoretic Movement: During telophase, the hourglass shape of dividing cells creates a non-uniform electric field that drives polar macromolecules and organelles toward the cleavage furrow, disrupting cell integrity and leading to defective cytokinesis.

DNA Damage Repair Interference: TTFields downregulate Fanconi anemia (FA)-BRCA DNA repair pathway genes, inducing a "BRCAness" state that enhances sensitivity to DNA-damaging chemotherapies like cisplatin. This molecular mechanism provides the scientific rationale for combining TTFields with platinum-based chemotherapy.

Immune Activation: TTFields-treated cancer cells release damage-associated molecular patterns (DAMPs) including HMGB1, calreticulin, and ATP, triggering immunogenic cell death. They also activate the cGAS/STING pathway and AIM2 inflammasomes, producing proinflammatory cytokines and type 1 interferons — effectively converting tumors from immunologically "cold" to "hot."

Membrane Permeability: TTFields reversibly alter cancer cell membrane structure, increasing permeability to chemotherapeutic agents. This effect appears specific to neoplastic cells and was confirmed by electron microscopy.

Cell Motility Inhibition: Through disruption of microtubule organization and activation of GEF-H1/RhoA/ROCK signaling, TTFields reduce cancer cell migration and invasion — potentially limiting metastatic spread.

Why Mesothelioma Is Especially Sensitive to TTFields

Preclinical studies have found that mesothelioma cell lines are among the most sensitive to TTFields treatment across all cancer types studied, both in terms of cell viability and clonogenic survival. This high sensitivity may relate to increased DNA double-strand break formation, elevated expression of cell cycle arrest proteins, and reduced FA-BRCA pathway protein expression observed in mesothelioma cells under TTFields treatment. Additionally, mesothelioma grows as a superficial tumor on thoracic pleural surfaces, making it anatomically accessible to electric field delivery through the chest wall.

Mannarino and colleagues further demonstrated that epithelioid mesothelioma cells are more sensitive to TTFields than sarcomatoid cells, with a distinct G2/M-phase block observed in epithelioid cells versus a milder general cell cycle delay in sarcomatoid cells. This aligns with STELLAR clinical findings where epithelioid patients achieved superior outcomes.

How Does the Optune Lua Device Work?

System Components

The Optune Lua Treatment Kit consists of several integrated components designed for continuous, portable use:

• Electric Field Generator: A portable device that produces TTFields at preset parameters — 150 kHz frequency, 1.414 A RMS maximum output, with an average field intensity of 0.7 V/cm delivered to the lungs
• Insulated Transducer Arrays: Four adhesive patches containing ceramic disc electrodes (large arrays: 20 discs; small arrays: 13 discs) embedded in a flexible circuit board with hydrogel and thermistors for temperature monitoring
• Rechargeable Batteries: Four batteries included, each lasting approximately one hour of operation
• Power Supply: For stationary use (overnight or while seated)
• Connection Cable and Carrying Bag: Over-the-shoulder bag for daily portability

Device Evolution

Feature	1st Generation (NovoTTF-100L)	2nd Generation (Optune Lua)
Total Weight	2.7 kg (6 lbs)	1.2 kg (2.7 lbs)
Device Weight	0.9 kg	0.7 kg
Battery Weight	1.8 kg	0.5 kg
Array Design	ILE model	Improved ITE model (more flexible)
Dimensions	Device: 21 × 21 × 4.5 cm; Battery: 21 × 21 × 2.8 cm	18 × 5.8 × 19 cm (integrated)

Array Placement and Compliance

Array placement is personalized for each patient based on tumor location, patient gender, and body size. Positions are determined using NovoCure's Clinical Practice Guidelines and the treating physician's judgment, supported by NovoCure's TorsoMAX software for generating digital layout maps.

TTFields therapy is administered continuously with a recommended minimum of 18 hours per day (75% of each 24-hour period). The device automatically records daily usage data in internal log files, generating monthly reports for adherence tracking. In the STELLAR trial, the median daily usage during the first 3 months was 16.3 hours per day. Real-world data from a single U.S. center reported a median of 12.5 hours per day, with investigators citing hot or humid climate and patient frailty as contributing factors.

Arrays must be replaced at least twice per week (every 4 days at most), with array position shifted by 1–2 cm at each change to reduce skin irritation. Patients should have at least 12 extra transducer arrays on hand at all times.

What Did the STELLAR Trial Show?

The STELLAR study (EF-23; NCT02397928) is the landmark clinical trial that established TTFields as a viable treatment option for malignant pleural mesothelioma and formed the basis for FDA approval.

Trial Design

STELLAR was a prospective, international, phase 2, single-arm study that evaluated TTFields therapy delivered to the thorax in combination with standard first-line chemotherapy for unresectable MPM. The study enrolled 80 patients at 12 European sites from February 2015 to March 2017. Treatment consisted of continuous TTFields at 150 kHz (≥18 hours/day) via the NovoTTF-100L system plus up to 6 cycles of pemetrexed with platinum chemotherapy (cisplatin or carboplatin at investigator's choice). After completing chemotherapy, patients who remained progression-free continued TTFields alone as maintenance until disease progression, unacceptable toxicity, or patient decision.

Efficacy Results

Endpoint	Overall (N=80)	Epithelioid (n=53)	Non-Epithelioid (n=21)
Median OS	18.2 months (95% CI: 12.1–25.8)	21.2 months	12.1 months
1-Year Survival	62.2%	—	—
2-Year Survival	41.9%	—	—
Median PFS	7.6 months (95% CI: 6.7–8.6)	8.3 months	6.5 months
Objective Response Rate	40%	—	—
Disease Control Rate	97%	—	—

The median OS of 18.2 months compared favorably to the historical control of 12.1 months from the pivotal Vogelzang 2003 study of pemetrexed plus cisplatin. The median duration of response was 5.7 months. Among 72 evaluable patients, 29 achieved partial response (40%) and 41 had stable disease (57%), yielding a disease control rate of 97% with only 3% demonstrating progressive disease.

How Does STELLAR Compare to Other Landmark Trials?

Trial	Treatment	Phase	Median OS
STELLAR (2019)	TTFields + pem/plat	Phase 2 (single-arm)	18.2 months
Vogelzang (2003)	Pemetrexed + cisplatin	Phase 3 (RCT)	12.1 months
MAPS (2016)	Pem + cis + bevacizumab	Phase 3 (RCT)	18.8 months
CheckMate 743 (2021)	Nivolumab + ipilimumab	Phase 3 (RCT)	18.1 months

Limitations of the STELLAR Trial

Independent reviewers have identified important limitations inherent to STELLAR's single-arm, phase 2 design:

• No randomized control group — efficacy was compared only to historical controls, making it impossible to attribute the survival benefit solely to TTFields
• Potential sampling bias in a heterogeneous cancer like pleural mesothelioma
• The FDA's HDE approval statement explicitly notes that "the effectiveness of this device for this use has not been demonstrated"
• Cross-trial comparisons with different patient populations and eligibility criteria are inherently unreliable

However, the sample size (N=80) was relatively large for a mesothelioma trial, and baseline patient characteristics were comparable to those in other first-line MPM studies such as MAPS and LUME-Meso.

Long-Term Survivor Cases

Two notable long-term cases from the STELLAR study have been reported in the peer-reviewed literature:

• A 63-year-old male with stage 4 epithelioid MPM who achieved TTFields usage of ≥75% per day remained in remission for over 8 years after completing 4.5 months of combined TTFields/chemotherapy followed by TTFields maintenance
• A 52-year-old male with stage 3 MPM who received TTFields therapy for 16 months achieved progression-free survival well beyond median expectations

Both cases achieved the recommended 75% daily usage threshold, supporting the dose-response relationship between TTFields usage time and outcomes.

How Did TTFields Receive FDA Approval?

The Humanitarian Device Exemption Pathway

The NovoTTF-100L System received FDA approval on May 23, 2019 under the Humanitarian Device Exemption (HDE) pathway (HDE number: H180002). The HDE pathway was created to encourage development of treatments for rare diseases affecting fewer than 8,000 patients per year in the United States — mesothelioma qualifies with approximately 3,000 new cases annually.

The approved indication is the treatment of adult patients with unresectable, locally advanced or metastatic malignant pleural mesothelioma, to be used concurrently with pemetrexed and platinum-based chemotherapy. Under HDE, the effectiveness threshold is lower than for Premarket Approval (PMA) — the device must show "probable benefit" rather than demonstrated effectiveness.

This was the first FDA-approved mesothelioma treatment in more than 15 years — since pemetrexed received approval in 2004.

TTFields Regulatory Approvals Across Cancer Types

Indication	Year	Pathway	Pivotal Trial
Recurrent glioblastoma	2011	PMA	EF-11
Newly diagnosed glioblastoma	2015	PMA	EF-14
Malignant pleural mesothelioma	2019	HDE	STELLAR
Metastatic NSCLC (post-platinum)	2024	PMA	LUNAR

TTFields also received Conformité Européenne (CE) certification in Europe based on STELLAR results. Globally, more than 40,000 patients have been treated with TTFields across all four approved indications.

What Is the Treatment Protocol for TTFields Therapy?

First-Line Treatment Regimen

TTFields is approved for first-line use in combination with pemetrexed and platinum-based chemotherapy. The standard treatment protocol involves three phases:

Phase 1 — Concurrent Therapy: Continuous TTFields at 150 kHz (≥18 hours/day) delivered by two pairs of transducer arrays placed on the patient's torso, combined with up to 6 cycles of pemetrexed (500 mg/m²) plus cisplatin (75 mg/m²) or carboplatin, administered every 3 weeks.

Phase 2 — Maintenance: After completing chemotherapy, patients continue TTFields therapy alone as maintenance until disease progression, unacceptable toxicity, or patient/physician decision to stop.

In the STELLAR trial, patients received a median of 8 TTFields treatment cycles (range 2–41) and a median of 6 chemotherapy cycles. Among patients who progressed, 44 (56%) received post-study therapy, primarily second-line chemotherapy or pemetrexed rechallenge.

Contraindications

TTFields therapy is contraindicated in patients with:

• Implanted electronic medical devices (pacemakers, defibrillators)
• Known sensitivity to conductive gels (ECG or TENS-type)
• Requirement for supplemental oxygen
• Pregnancy (reproductive-age patients must use effective contraception)

Combination with Immunotherapy

Although no published clinical trial has specifically combined TTFields with immune checkpoint inhibitors in mesothelioma, preclinical evidence strongly supports this approach. Studies in mouse models demonstrated that concurrent TTFields with anti-PD-1 therapy significantly decreased tumor volume compared to either modality alone, with increased tumor-infiltrating lymphocytes. TTFields upregulate PD-L1 expression and promote conversion of the tumor microenvironment from immunologically "cold" to "hot." The LUNAR trial for NSCLC demonstrated that TTFields plus an immune checkpoint inhibitor yielded dramatic survival improvement over immunotherapy alone (19.0 vs 10.8 months), providing a strong rationale for investigating this combination in mesothelioma.

What Are the Side Effects of TTFields?

Dermatologic Adverse Events

The primary and essentially only adverse event attributable to TTFields is localized skin irritation beneath the transducer arrays. Based on STELLAR and a meta-analysis of four torso-based TTFields studies (N=192):

Adverse Event	Incidence
Any dermatologic adverse event	58%
Grade 1-2 dermatitis	53%
Grade 3-4 dermatologic events	6%
Grade 1-2 pruritus	9%
Device-related treatment discontinuation	5% (STELLAR)

Skin adverse events are principally caused by contact between the skin and array components (adhesive tape, hydrogel-covered ceramic discs) rather than by the electric fields themselves.

Prevention and Management

Key risk factors for skin adverse events include age, array contact with surgical scars, history of contact dermatitis, excessive sweating, prior radiation exposure, and use of high-dose systemic corticosteroids. Recommended prevention strategies include:

• Regular skin inspection during array changes
• Skin moisturization with mild, non-petroleum products compatible with TTFields therapy
• Adequate skin shaving and cleansing before array application
• Array position shifting (1–2 cm) at each replacement
• Beginning prophylaxis early (skin adverse events may develop in the first month)

For established skin events, early intervention is recommended. Mild dermatitis responds to topical high-potency corticosteroids, calcineurin inhibitors, or phosphodiesterase 4 inhibitors. Contact dermatitis requires isolation of affected skin from adhesives and topical or oral antibiotics if secondary infection develops.

Systemic Safety

TTFields therapy produces no systemic side effects. Animal studies and clinical experience have shown no evidence of cardiac toxicity. The device includes thermistors in each array that continuously monitor skin temperature, automatically shutting off if temperature exceeds 41°C. The LUNAR trial (N=133 TTFields-treated NSCLC patients) confirmed similar safety findings — only 6% reported a grade 3 TTFields-related adverse event, with no deaths attributed to the device.

How Does TTFields Compare to Other Mesothelioma Treatments?

TTFields occupies a unique position in the mesothelioma treatment landscape as a non-invasive, device-based therapy that can be combined with standard chemotherapy without adding systemic toxicity.

Cross-Indication TTFields Comparison

Cancer Type	Device	Frequency	Trial Phase	N	Median OS
Newly diagnosed GBM	Optune	200 kHz	Phase 3 (RCT)	695	20.9 months
Recurrent GBM	Optune	200 kHz	Phase 3 (RCT)	237	6.6 months
Unresectable MPM	Optune Lua	150 kHz	Phase 2 (single-arm)	80	18.2 months
Metastatic NSCLC	Optune Lua	150 kHz	Phase 3 (RCT)	276	13.2 months

The key difference for mesothelioma is the lack of a randomized controlled trial, unlike both GBM and NSCLC indications where phase 3 RCTs established a significant survival benefit.

Dose-Response Relationship

While limited data exist specifically for mesothelioma, the relationship between TTFields usage time and outcomes has been robustly demonstrated in glioblastoma research:

• In EF-11 (recurrent GBM): Patients using TTFields ≥18 hours/day had median OS of 7.7 months versus 4.5 months for fewer than 18 hours (p=0.04)
• In EF-14 (newly diagnosed GBM): A threshold of 50% usage was needed for improved PFS and OS; patients with greater than 90% usage showed median OS of 25 months and 5-year survival of 29%
• In PRiDe registry: Median OS was 13.5 months with ≥75% daily compliance versus 4.0 months with less than 75%

These data strongly support encouraging mesothelioma patients to maximize daily TTFields usage for optimal therapeutic benefit.

What Is the Cost of TTFields Therapy?

Device Pricing

The estimated cost of TTFields therapy is approximately $21,000 per month, based on published data primarily from the glioblastoma indication. This covers equipment rental, replacement arrays and supplies, and ongoing device support. In the STELLAR trial, patients received a median of 8 treatment cycles (approximately 5.5 months of continuous use), implying a typical total treatment cost in the range of $115,000 to $170,000 before insurance.

Insurance and Financial Assistance

Coverage for TTFields therapy varies by payer and region:

• Medicare: Medicare covers TTFields therapy for glioblastoma; coverage status specifically for mesothelioma varies by regional carrier
• Private Insurance: Coverage varies and prior authorization is typically required. Some private insurers consider TTFields investigational for mesothelioma given the HDE pathway
• NovoCure Patient Support: NovoCure provides financial assistance for qualifying patients based on income and insurance status and assists with billing and payment processes

International Access

TTFields therapy for mesothelioma is commercially available in the United States (under HDE) and in Europe (CE mark). More than 110 U.S. hospitals are certified to offer TTFields for MPM. Reimbursement varies internationally, with the therapy covered in Austria, Czechia, France, Germany, Israel, Japan, Spain, Sweden, and Switzerland across approved indications.

Cost-Effectiveness

Published cost-effectiveness analyses for TTFields exist primarily for NSCLC using LUNAR trial data. An analysis estimated an incremental cost-effectiveness ratio (ICER) of $89,808 per quality-adjusted life year (QALY) for TTFields plus an immune checkpoint inhibitor or docetaxel versus those agents alone, falling within standard U.S. willingness-to-pay thresholds. No published cost-effectiveness analysis specific to mesothelioma was identified as of early 2026.

What Do Current Guidelines Say About TTFields?

NCCN Guidelines

The NCCN Clinical Practice Guidelines for Malignant Pleural Mesothelioma Version 2.2025 do not reference TTFields therapy. This omission likely reflects the single-arm phase 2 evidence base and HDE (rather than PMA) regulatory status.

ASCO Guidelines (2025 Update)

The ASCO Treatment of Pleural Mesothelioma guideline update (published in early 2025, the first update since 2018) focuses on surgical cytoreduction, immunotherapy (nivolumab plus ipilimumab; pembrolizumab plus chemotherapy), chemotherapy, pathology, and germline testing. TTFields is not prominently featured in the ASCO guideline recommendations.

European Guidelines

The Onkopedia guidelines (Germany) include TTFields as a treatment option for pleural mesothelioma, noting the 150 kHz frequency and combination with chemotherapy. The CE certification in Europe has supported inclusion in some European treatment algorithms.

NCI PDQ Summary

The NCI Physician Data Query (PDQ) mesothelioma treatment summary lists surgery, radiation, chemotherapy, immunotherapy, and targeted therapy, but does not specifically feature TTFields in its standard treatment sections.

Understanding the Guideline Gap

The absence of TTFields from NCCN and ASCO guidelines reflects the current evidence standard in oncology, where phase 3 randomized data typically underpin Category 1 recommendations. TTFields' inclusion in clinical practice is supported by FDA HDE approval but not by the randomized controlled trial data that guidelines committees generally require for strong endorsements. Independent reviewers have called for a randomized phase 3 study as "paramount" to establishing TTFields' true added benefit in mesothelioma.

What Clinical Trials Are Currently Underway?

TIGER Meso (NCT05538806)

The TIGER Meso study is a post-authorization, observational, real-world study sponsored by NovoCure with an estimated enrollment of 198 patients at 23 centers. It aims to collect real-life data on TTFields use in routine clinical care for pleural mesothelioma, including combinations with various systemic agents. The study is currently enrolling.

TTFields Plus Immunotherapy

As of March 2026, no dedicated randomized trial combining TTFields with checkpoint inhibitors specifically in mesothelioma has been registered. However, the dramatic results from the LUNAR trial in NSCLC — where TTFields plus an immune checkpoint inhibitor yielded median OS of 19.0 months versus 10.8 months for immunotherapy alone — provide a strong scientific rationale for investigating this combination in mesothelioma.

Phase 3 Mesothelioma Trial

As of March 2026, no phase 3 randomized mesothelioma trial for TTFields has been registered on ClinicalTrials.gov. Independent reviewers have called for such a study as essential to establishing the true clinical benefit of TTFields in this disease.

Next-Generation Devices

NovoCure continues to improve the TTFields platform with smaller, lighter devices and more flexible array designs. The second-generation NovoTTF-200T is substantially smaller (1.2 kg versus 2.7 kg) with improved digital technology and more flexible ITE arrays designed to increase patient comfort and compliance.

What Is the Patient Experience Like?

Daily Living with TTFields

The Optune Lua device is designed to be as minimally disruptive to daily life as possible:

• Portability: The second-generation device weighs only 1.2 kg and can be carried in a shoulder bag or backpack, enabling patients to maintain most normal activities
• Showering: Arrays must be removed for showering and replaced with new arrays afterward
• Sleep: The device can be connected to an external power supply overnight, eliminating the need to change batteries during sleep
• Travel: Patients can travel with the device but should carry extra batteries (each lasting approximately one hour) for periods away from power sources
• Work: Patients can generally continue working while wearing the device, as it operates silently and can be worn under clothing

Caregiver Support

Patients should ideally have at least one caregiver who can assist with removing and reapplying arrays and managing skin adverse events. Patient and caregiver education and training before starting TTFields therapy are essential components of treatment. NovoCure Device Support Specialists provide technical training, education, and ongoing support to both patients and caregivers.

Quality of Life Considerations

In the STELLAR trial, quality of life was assessed using ECOG performance status and a visual analog scale for cancer-related pain until disease progression. No validated quality-of-life instrument results (such as the EORTC QLQ-C30) from STELLAR have been published specifically for mesothelioma. In GBM studies (EF-14), TTFields did not significantly worsen quality of life compared to temozolomide alone, except for a higher incidence of itchy skin — suggesting that the therapy is generally well-tolerated.

Historical Development of TTFields Technology

Year	Milestone
Late 1990s	Prof. Yoram Palti (Technion, Israel) begins exploring electric fields as cancer treatment
2000	NovoCure founded; preclinical research lab established
2003	First patient treated with TTFields in clinical trial (Switzerland)
2011	First FDA approval: recurrent glioblastoma (PMA)
Feb 2015	STELLAR trial begins enrolling mesothelioma patients
2015	Second FDA approval: newly diagnosed GBM + temozolomide (PMA)
Mar 2017	STELLAR enrollment complete
May 2019	FDA HDE approval for mesothelioma (NovoTTF-100L)
2019	STELLAR results published in The Lancet Oncology (Ceresoli et al.)
Oct 2024	FDA PMA approval for metastatic NSCLC (LUNAR trial)
2025	Ceresoli & Gianoncelli comprehensive TTFields-mesothelioma review published

As of 2026, NovoCure is an international oncology company headquartered in Baar, Switzerland, with U.S. headquarters in Portsmouth, New Hampshire, and R&D facilities in Haifa, Israel. The company employs over 1,300 people and has treated more than 40,000 patients globally across all approved cancer indications.

Frequently Asked Questions

What is TTFields therapy for mesothelioma?

TTFields (Tumor Treating Fields) therapy uses alternating electric fields delivered through a wearable device called Optune Lua to disrupt cancer cell division. For mesothelioma, the device operates at 150 kHz and is worn continuously for at least 18 hours per day alongside standard chemotherapy. It received FDA approval in 2019 and was the first new mesothelioma treatment approved in over 15 years.

How effective is TTFields for mesothelioma?

In the landmark STELLAR trial, 80 patients treated with TTFields plus chemotherapy achieved a median overall survival of 18.2 months, compared to 12.1 months for chemotherapy alone (historical control). The 1-year survival rate was 62.2% and the 2-year survival rate was 41.9%. Patients with epithelioid mesothelioma had even better outcomes, with median survival reaching 21.2 months.

What are the side effects of TTFields?

The only side effects directly attributable to TTFields are skin reactions beneath the transducer arrays. About 53% of patients experience mild-to-moderate dermatitis, while serious skin reactions occur in approximately 6% of patients. Importantly, TTFields cause no systemic side effects — there is no nausea, hair loss, or immune suppression from the device itself.

How much does TTFields therapy cost?

TTFields therapy costs approximately $21,000 per month, covering device rental, replacement arrays, and support services. A typical treatment course (median 8 cycles) may total $115,000 to $170,000 before insurance. NovoCure offers financial assistance for qualifying patients, and insurance coverage varies by payer.

Is TTFields covered by insurance?

Insurance coverage for TTFields mesothelioma therapy varies. Medicare covers TTFields for glioblastoma, but mesothelioma-specific coverage depends on the regional carrier. Private insurance typically requires prior authorization, and some insurers consider TTFields investigational for mesothelioma given the HDE approval pathway. NovoCure assists patients with billing and insurance navigation.

Can TTFields be combined with immunotherapy?

While no clinical trial has specifically combined TTFields with checkpoint inhibitors in mesothelioma, preclinical evidence strongly supports this approach. TTFields upregulate PD-L1 expression and promote immunogenic cell death. The LUNAR trial for lung cancer showed dramatic survival benefits when combining TTFields with immunotherapy. Real-world observational data from the TIGER Meso study may provide additional insight.

Why isn't TTFields in the NCCN guidelines?

The NCCN guidelines for mesothelioma (Version 2.2025) do not reference TTFields, likely because the evidence comes from a single-arm phase 2 trial rather than a randomized phase 3 study. NCCN typically requires randomized controlled trial data for Category 1 recommendations. However, TTFields remains an FDA-approved treatment option available at certified centers.

Who is eligible for TTFields therapy?

TTFields therapy is approved for adults with unresectable, locally advanced or metastatic malignant pleural mesothelioma. Patients must not have implanted electronic medical devices (pacemakers, defibrillators), known sensitivity to conductive gels, or require supplemental oxygen. Treatment is initiated at certified centers where NovoCure support specialists provide training for patients and caregivers.

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