What happened

Shares of NovoCure (NVCR 3.31%) were crashing 32.8% lower as of 11:24 a.m. ET on Monday. The sharp sell-off came after the company announced that a phase 3 study evaluating its tumor treating fields (TTFields) therapy in treating platinum-resistant ovarian cancer didn't meet the primary endpoint of overall survival.

Patients in the late-stage study who received TTFields plus the chemotherapy paclitaxel had a median overall survival rate of 12.2 months. While that was better than the median overall survival rate of 11.9 months for patients treated with paclitaxel alone, the difference wasn't statistically significant.

So what

NovoCure's TTFields therapy uses electric fields in an attempt to kill cancer cells. The therapy has already been approved for treating glioblastoma (an aggressive type of brain cancer) and mesothelioma (a cancer linked to exposure to asbestos).

TTFields also met the primary endpoint of a late-stage study targeting non-small cell lung cancer and plans to seek U.S. Food and Drug Administration (FDA) approval in the indication. However, the healthcare stock has still performed dismally so far this year.

Positive results in the ovarian cancer study could have provided a much-needed spark for NovoCure. Hopes of success in the indication are now greatly diminished, but might not be totally gone.

NovoCure noted that an analysis of some subgroups in its phase 3 study of TTFields in treating ovarian cancer suggested "a potential survival benefit in patients who received only one prior line of therapy." Executive Chairman William Doyle said that the company was "encouraged" by this and that it could point to the potential for TTFields to provide a clinical benefit when given to patients as an earlier treatment.

Now what

NovoCure expects to finalize its premarket approval submission to the FDA for TTFields in treating non-small cell lung cancer later this year. It also anticipates reporting data from a phase 3 study targeting brain metastases in the first quarter of 2024 followed by data from another late-stage study aimed at pancreatic cancer in the second half of next year.