Tumor Treating Fields (TTFields) and Mesothelioma

How Is Tumor Treating Fields Used to Treat Mesothelioma?

Tumor Treating Fields is a new type of anti-cancer therapy that uses alternating electrical fields to limit cancer growth. It is combined with chemotherapy to control the growth of pleural mesothelioma.

In May 2019, TTFields became the second pleural mesothelioma treatment to be approved by the U.S. Food and Drug Administration.

The first mesothelioma treatment approved by the FDA was a chemotherapy regimen combining Alimta (pemetrexed) with cisplatin or carboplatin, which was approved in 2004. TTFields is administered in combination with this chemotherapy regimen.

A company called Novocure invented the noninvasive technology and has been developing Tumor Treating Fields since 2000. TTFields received its first approval from the FDA in 2011 to treat a type of brain cancer called glioblastoma.

The clinical trial that led the FDA to approve TTFields for pleural mesothelioma reported an overall survival of 18.2 months.

Patients in the trial who received only chemotherapy lived 12.1 months. The addition of TTFields helped patients live an average of six months longer.

TTFields doesn’t offer a cure for mesothelioma, but it can significantly improve survival with a low risk of side effects.

How Does TTFields Work?

Tumor Treating Fields applies alternating electrical fields of an intermediate frequency that are low in intensity.

The electrical fields are delivered through insulated pads that adhere to skin. The electrical field frequency is 100 to 300 kilohertz, and the intensity is delivered at 1 to 3 volts per centimeter.

Research shows that applying this range of alternating frequencies to cancer cells has the power to disrupt certain proteins that are essential to cell division.

When the electrical fields enter a cancer cell, they prevent these proteins from functioning properly. This stops cancer cells from multiplying, which limits tumor growth and may kill some cancer cells.

How Is TTFields Administered?

Novocure’s TTFields delivery system, also known as the NovoTTF-100L System, is a portable device that can be used anywhere.

The system comes with a TTFields-generating device, battery charger and rechargeable batteries, power supply, insulated pads and a carrying bag.

The treatment is designed for continual use at home or on-the-go. The carrying bag can be worn as a backpack or held in your hand.

The therapy is applied with three pads attached to the front and back of a patient’s chest. The pads are changed every two to three days, and the area must be shaved. It involves no skin incisions or insertion of any medical devices into the body.

Patients are advised to wear NovoTTF-100L for 18 to 20 hours a day until their cancer progresses.

Patients can carry on with their lives while receiving treatment. They can run errands, take walks and do house chores while the therapy is administered.

However, keeping the device charged may present some logistical challenges for active people. NovoTTF-100L is plugged into a power supply or uses a large rechargeable battery pack that must be carried to power the device.

Every three weeks, patients will receive chemotherapy with Alimta and cisplatin or carboplatin for six cycles. Research shows that using NovoTTF-100L does not increase the toxicity of chemotherapy.

NovoTTF-100L is only prescribed with chemotherapy. That means patients must take chemotherapy to use the device.

Side Effects of TTFields for Mesothelioma

The most common side effects of TTFields plus chemotherapy in pleural mesothelioma patients include:

• Device skin reaction

• Itchy skin

• Constipation

• Nausea

• Fatigue

• Cough

• Chest pain

• Anemia

Less common side effects include:

• Treatment-related skin toxicity

• Allergic reaction to transducing patches

• Pain or skin burns from patches that overheat

• Skin infections

• Skin breakdown or skin ulcers

• Tingling sensation beneath the patches

• Muscle twitching

Skin irritation is reported in nearly half of patients who receive the therapy, but only 4% of patients report a severe level of irritation.

Contraindications, Warnings and Precautions

Do not use TTFields if:

• You have an active implanted medical device such as a pacemaker

• You have a sensitivity to conductive hydrogels (severe allergic reactions are possible)

• You are pregnant or trying to get pregnant

The NovoTTF-100L System can only be prescribed by a mesothelioma doctor that has completed required certification training.

Patients with an underlying serious skin condition on the chest may not be able to receive Novocure’s mesothelioma treatment.

Research on Mesothelioma and TTFields

The clinical trial that led the FDA to approve NovoTTF-100L for pleural mesothelioma reported the following:

• Patients lived an average of six months longer with the addition of NovoTTF-100L (18.2 months) compared to those only receiving chemotherapy (12.1 months).

• More than 97% of patients responded to the therapy with tumor shrinkage or no new tumor growth.

• Patients with epithelial mesothelioma, which responds best to treatment, lived 21.2 months.

• Participants using NovoTTF-100L had no new cancer growth for an average of 7.6 months. Those only receiving chemotherapy had no new cancer growth for 5.7 months.

Availability of TTFields for Mesothelioma

In October 2019, a patient at West Cancer Center in Memphis, Tennessee, became the first pleural mesothelioma patient outside of a clinical trial to use NovoTTF-100L since it was approved by the FDA.

Other cancer centers are starting to use the novel treatment, including the Miami Cancer Institute in Florida and the Oregon Health & Sciences University in Portland. More than a dozen other centers throughout the U.S. are awaiting approval.

Novocure’s other TTFields device, called Optune, is specially designed to treat glioblastoma. It cannot be used to treat mesothelioma.

If you are interested in TTFields, ask your doctor if they are certified to prescribe the NovoTTF-100L System, and ask if you qualify for the therapy. The FDA has approved it only for pleural mesothelioma patients with inoperable tumors.