May 24, 2019
2 min read

FDA approves tumor-treating fields system for mesothelioma

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The FDA approved NovoTTF-100L, a tumor-treating fields delivery system, for use in combination with pemetrexed plus platinum-based chemotherapy for the first-line treatment of patients with unresectable, locally advanced or metastatic malignant pleural mesothelioma.

NovoTTF-100L (Novocure) — a noninvasive, antimitotic treatment that delivers tumor-treating fields to the tumor — represents the first treatment approved for malignant pleural mesothelioma in more than 15 years. The tumor-treating fields therapy uses electric fields at specific frequencies to disrupt solid tumor cancer cell division.

Prior to this approval, pemetrexed plus cisplatin was the only FDA-approved therapy for malignant pleural mesothelioma — a rare cancer, with 3,000 diagnoses annually in the U.S., that is linked to asbestos exposure.

“Malignant pleural mesothelioma is a devastating disease, with only 10% to 20% of patients being candidates for surgery to remove the tumor,” Mary Hesdorffer, NP, executive director of the Mesothelioma Applied Research Foundation, said in a press release. “Typically, patients [with mesothelioma] who cannot have surgery receive palliative care to mitigate their symptoms. NovoTTF-100L provides [patients with unresectable malignant pleural mesothelioma] with a treatment option that may improve survival. We are encouraged by the FDA approval and hope it is just the beginning of innovation in the treatment of this aggressive disease.”

The FDA based the decision, in part, on data from STELLAR, a prospective, single-arm trial that evaluated the safety and efficacy of NovoTTF-100L plus first-line chemotherapy among 80 patients with unresectable and previously untreated malignant pleural mesothelioma who were eligible to receive pemetrexed and cisplatin or carboplatin.

OS served as the study’s primary endpoint. Secondary endpoints included overall response rate, PFS and safety.

Median OS was 18.2 months (95% CI, 12.1-25.8) across all patients in the trial who received NovoTTF-100L plus first-line chemotherapy. Median OS was 21.1 months for the 53 patients with epithelioid malignant pleural mesothelioma, and 12.1 months for the 21 patients with nonepithelioid disease.

Sixty-two percent of patients (n = 80) achieved 1-year OS.

Of the 72 patients with at least one follow-up CT scan, 97% showed disease control. Forty percent of patients achieved partial response, 57% had stable disease and 3% experienced progressive disease.

Median PFS was 7.6 months.

Researchers reported no increase in serious adverse events with the use of NovoTTF-100L in combination with chemotherapy. The most common device-related adverse event of NovoTTF-100L was mild to moderate skin irritation.

NovoTTF-100L received FDA approval under the Humanitarian Device Exemption pathway, created to encourage the innovation of therapies for underserved patients with rare diseases.


Since the FDA approved another tumor-treating fields delivery system — Optune (Novocure) — for glioblastoma in 2011, more than 12,000 patients with glioblastoma have received the therapy.

“Since 2000, we have been developing and commercializing tumor-treating fields to extend survival in some of the most aggressive forms of cancer,” Bill Doyle, Novocure’s executive chairman, said in the release. “FDA approval of NovoTTF-100L provides patients with the first FDA-approved treatment for [malignant pleural mesothelioma] in more than 15 years and, as our first FDA-approved torso cancer indication, marks a major milestone for Novocure. We are thankful for the patients, caregivers and health care providers who partnered with us to make this possible.”