Tumor Treating Fields (TTFields) therapy has cleared a key regulatory hurdle in Japan. According to BioSpace, Japan’s Ministry of Health, Labour and Welfare (MHLW) approved Novocure’s wearable Optune Lua® system for concurrent use with PD-1/PD-L1 inhibitors in adult patients with unresectable, advanced or recurrent non-small cell lung cancer (NSCLC) whose disease progressed on or after platinum-based chemotherapy. The decision effectively adds a noninvasive, device-based therapy to later-line options for Japanese patients.
Optune Lua delivers low-intensity, alternating electric fields through adhesive arrays placed on the chest. These fields disrupt cancer cell division and may make tumors more susceptible to systemic therapy—all without chemotherapy-like systemic toxicities. As BioSpace noted, the approval specifically pairs TTFields with checkpoint inhibitors, reflecting where the strongest clinical signal was seen.
The MHLW action is grounded in the global phase 3 LUNAR trial, which compared standard therapy alone (PD-1/PD-L1 inhibitor or docetaxel) versus the same treatment plus TTFields in patients whose metastatic NSCLC had progressed following a platinum regimen. OncLive reports that LUNAR met its primary end point, showing a median overall survival (OS) of 13.2 months with TTFields combinations versus 9.9 months with standard therapy alone. Notably, in the prespecified subgroup receiving a PD-1/PD-L1 inhibitor, median OS was 19.0 months with TTFields versus 10.8 months without—an 8-month advantage that drove the concurrent-use label now granted in Japan.
Safety outcomes also factored into the decision. In LUNAR, most TTFields-related adverse events were low-grade skin reactions beneath the arrays; grade 3 skin toxicity occurred in a small minority of patients and there were no device-related grade 4/5 events, according to OncLive. That profile helps explain why clinicians view TTFields as additive to immunotherapy rather than a replacement—something that can be layered onto existing regimens with manageable incremental risk.
The Japanese approval follows the U.S. Food and Drug Administration’s October 2024 decision authorizing Optune Lua for use with PD-1/PD-L1 inhibitors or docetaxel in metastatic NSCLC after platinum chemotherapy, again on the strength of LUNAR. For Japanese clinicians, the new label provides a defined path to combine TTFields with checkpoint blockade in patients whose disease has already tested the limits of standard sequencing.
What it could mean for practice in Japan:
- New option after platinum failure. The indication targets a population with limited choices, enabling oncologists to build on immunotherapy rather than pivoting solely to cytotoxic agents.
- Potential synergy with immunotherapy. The largest survival benefit in LUNAR appeared when TTFields were paired with PD-1/PD-L1 inhibitors, which aligns with the approval’s concurrent-use framing.
- Noninvasive delivery with localized side effects. Because TTFields act regionally and are worn at home, the main trade-off is skin care and adherence, not systemic toxicity, based on the trial safety data.
According to BioSpace, Novocure characterized the ruling as an important expansion for its thoracic oncology portfolio and indicated that the company is preparing for commercial availability in Japan. As with any device-based therapy, real-world uptake will hinge on reimbursement, logistics (array placement, nursing support), and patient adherence to daily wear time. But for patients and physicians confronting disease after platinum chemotherapy, TTFields now represents a newly approved, mechanistically distinct tool to extend survival alongside immunotherapy.
Read Our Special Article About Immunotherapy of Lung Cancer
Written By Aren Karapetyan, MD