In sharp contrast to study results presented earlier this year showing that Novocure’s Tumor Treating Fields technology, or TTFields, could significantly increase the overall survival rate for patients with platinum-resistant, metastatic non-small cell lung cancer, the treatment fell short in a more recent study of ovarian cancer patients.
TTFields failed to meet its primary endpoint in the INNOVATE-3 clinical trial, Novocure announced Monday. The trial was testing the combination of TTFields and the chemotherapy medication paclitaxel in patients with platinum-resistant ovarian cancer, a group that makes up about 20% of all ovarian cancer patients, according to Novocure.
The technology’s primary goal in the study was to outperform paclitaxel alone in extending patients’ overall survival. After the study’s 18-month follow-up, however, both groups—those who received TTFields and paclitaxel as well as those treated only with the chemo drug—demonstrated almost equal survival rates.
TTFields generates high-frequency electric fields that are sent through the skin with an aim of interrupting cancer cells’ division and reproduction. It was first cleared by the FDA over a decade ago, in 2011, to help treat glioblastoma.
The INNOVATE-3 study results span about 280 participants in each of the two treatment groups. Patients enrolled in the study had already undergone up to five other therapeutic approaches for their ovarian cancer without significant success.
After the treatment period, the researchers calculated a median overall survival rate of 12.2 months for the TTFields group—only a little over a week longer than the 11.9-month median among the paclitaxel-only group.
Novocure is still in the process of working with the study’s investigators to prepare the full study results for release.
Bright spots among the disheartening results included Novocure’s report that the TTFields therapy had been well tolerated across the group as well as the finding from a subgroup analysis that patients who had undergone only one other treatment before joining the study may experience an extended survival rate compared to the paclitaxel-only patients.
That finding “suggests the potential for a clinical benefit when TTFields therapy is initiated early in a patient’s treatment journey,” William Doyle, Novocure’s executive chairman, said in the announcement, adding that the subgroup analysis was “encouraging” amid the “disappointing” results of the overall study.
Indeed, the researchers are continuing to delve into subgroup analyses of the trial data to parse out the patients who may experience the greatest benefit from TTFields therapy.
As David O’Malley, M.D., a primary investigator in the study, added in the announcement: “We see treatment exposure and number of prior therapies are relevant and can drive outcomes, and we will leverage these data as we explore and identify new opportunities to treat this deadly disease.”
Editor's note: This story was updated to correct the difference in survival between the TTFields and paclitaxel-only treatment groups. The former group's survival rate was approximately nine days longer than the latter's, not three months.