Researchers have announced the first successful therapy for managing relapsed malignant mesothelioma, a major milestone in treating the cancer.

An ongoing British study of second-line mesothelioma treatment shows that patients who receive the immunotherapy drug nivolumab, which goes by the brand name Opdivo, live significantly longer than placebo patients, according to a release outlining the study’s findings.

The phase III trial is the first to show improvement in overall survival for relapsed mesothelioma patients since at least 2004, according to the U.K. research team. That was when the standard first-line chemotherapy treatment of pemetrexed combined with either cisplatin or carboplatin was first licensed.

More Time

Broadly speaking, second-line treatments for recurrent mesothelioma fare poorly in staving off the disease. However researchers at the University of Southampton and the University of Leicester are seeing patients on nivolumab live “significantly longer”; on average, 10 weeks longer than placebo patients. The group disclosed their findings on Jan. 30 at the International Association for the Study of Lung Cancer (IASLC) World Conference on Lung Cancer in Singapore.

The randomized trial — dubbed the Checkpoint Blockade for Inhibition of Relapsed Mesothelioma (CONFIRM) study — involves 332 patients from 24 treatment centers in the U.K. All of the patients have previously been treated for unresectable and histologically confirmed malignant mesothelioma.

Participants were separated into two camps — epithelioid mesothelioma or non-epithelioid mesothelioma — before either receiving nivolumab as a monotherapy or a placebo instead.

Impressive But Incomplete

The results, while incomplete because data are still being collected, remain impressive.

Progression-free survival for nivolumab patients is pegged at three months versus 1.8 for those receiving the placebo. Those rates were notably improved after a year, with a 14.5 percent progression-free survival rate for nivolumab recipients compared to 4.9 percent for those who got the placebo.

The overall survival rate also shows promise, with nivolumab patients averaging 9.2 months versus 6.6 for placebo patients.

Because the study is incomplete, the researchers cautioned that the overall survival ratio could worsen, as only 232 cases out of a target of 291 are complete. The progression-free survival numbers are considered more solid, having recorded 310 cases out of a planned 284.

Heightened Complications

As can be expected, the treatment does not come without serious risk. Patients taking nivolumab are nearly 13 percent more likely to suffer severe or life-threatening complications than those taking the placebo (19 percent versus 6.3 percent). Additionally, 13.1 percent of all nivolumab patients had to discontinue the treatment due to toxicity, versus a mere 2.7 percent of placebo patients.

Despite these issues, the researchers noted that the immunotherapy drug’s safety profile was unchanged as a result of the study, with the group finding no new safety signals.

The New Standard?

According to one of the researchers involved, Professor Gareth Griffiths of the Southampton Clinical Trials Unit at the University of Southampton, the CONFIRM trial “gives good evidence that this treatment approach should be considered for the new standard of care for these patients.”

“Therapeutic alternatives are always welcome in the contest of a difficult-to-treat disease such as malignant pleural mesothelioma,” according to Dr. Giorgio Scagliotti, the interim president of the IASLC. “This study contributes to increase our range of treatment opportunities in the setting of relapsed/recurrent disease.”

The research, which was initially presented on Jan. 12 but embargoed until the conference started, was funded by the charities Cancer Research U.K. and Stand Up To Cancer. It has yet to be published in a peer-reviewed medical journal.