Adding Imfinzi (durvalumab) to standard chemotherapy as the first-line treatment of adults with extensive-stage small cell lung cancer (SCLC) continues to show survival benefits sustained now for two years, updated findings from the CASPIAN trial show.
The ongoing Phase 3 clinical trial (NCT03043872) supported Imfinzi’s recent approval by the U.S. Food and Drug Administration, after demonstrating that this combination reduced the risk of death by 27% compared to chemotherapy.
CASPIAN recruited 805 SCLC patients, who were randomly assigned to either AstraZeneca’s Imfinzi and standard chemotherapy (etoposide plus cisplatin or carboplatin) or to standard chemotherapy alone. In all these patients, cancer had spread within the lungs or elsewhere in the body.
Those treated with the Imfinzi combination completed four cycles of chemotherapy, while those on standard treatment received up to six cycles plus an optional form of radiation therapy (cranial irradiation).
The updated results — collected after a median follow-up of more than two years — showed that Imfinzi plus chemotherapy have sustained efficacy, maintaining a 25% reduction in the risk of death versus chemotherapy alone. These results represented an extended survival time from 10.5 months for those on standard chemotherapy to 12.9 months for patients taking the Imfinzi combination.
A post-hoc analysis estimated that 22.2% of Imfinzi-treated patients were alive at two years compared with 14.4% of those on standard treatment.
“These updated results from the CASPIAN trial show a remarkable 22% of patients still alive at 24 months, supporting the sustained benefits of treatment with Imfinzi plus chemotherapy,” Luis Paz-Ares MD, PhD, principal investigator in the CASPIAN trial, said in a press release.
“This is an effective 1st-line treatment in the extensive-stage setting, where improving outcomes has been a challenge and so few patients survive five years,” Paz-Ares added.
Imfinzi plus chemotherapy also showed other sustained benefits. A total of 11% of combination patients were alive and progression-free at 24 months, compared to 2.9% of those on chemotherapy alone.
Response rates were also better with Imfinzi (68% vs. 58%), and 13.5% of patients showed responses lasting two years or more compared with 3.9% of those responding to chemotherapy.
“After two years median follow-up, Imfinzi continues to show sustained and meaningful improvements in survival and prolonged treatment response for patients facing this devastating and aggressive disease,” said José Baselga, MD, PhD, executive vice president at AstraZeneca, which is marketing the therapy.
Consistent with previous studies, the number of severe and life-threatening adverse events were similar in both groups, as were the number of people who discontinued treatment.
“These data reinforce Imfinzi plus chemotherapy as an important new standard of care for extensive-stage small cell lung cancer patients, and this regimen offers patients convenient dosing every four weeks during maintenance,” Baselga added.
Regulatory authorities in the European Union and Japan are also reviewing the Imfinzi plus standard chemo combination for extensive-stage SCLC patients, which was first approved in Singapore.
“We look forward to bringing the benefits of Imfinzi to patients around the world,” Baselga said.
Imfinzi is a so-called immune checkpoint inhibitor that enhances the immune response against cancer cells by blocking a protein known as PD-L1. Cancer cells use PD-L1 to evade immune system attack.
Another Phase 3 clinical trial, called ADRIATIC (NCT03703297), is testing Imfinzi after chemoradiation therapy in patients with limited-stage small cell lung cancer (SCLC), a cancer that is typically limited to one lung and, possibly, to lymph nodes on one side of the chest.
ADRIATIC is currently enrolling eligible patients worldwide, and is expected to be finish by February 2024. More information can be found here.
