When given as a first-line therapy, Libtayo (cemiplimab) prolonged the survival of patients with advanced non-small cell lung cancer (NSCLC), compared with platinum-based chemotherapy, according to early data from a Phase 3 trial.
In addition to improving survival, Libtayo increased the proportion of people who responded to treatment, and lowered their risk of death or disease progression, compared with chemo. These positive findings are expected to form the basis of future submissions to U.S. and European regulatory agencies.
The study’s findings were recently presented as a late-breaking abstract, titled “EMPOWER-Lung 1: Phase III first-line (1L) cemiplimab monotherapy vs platinum-doublet chemotherapy (chemo) in advanced non-small cell lung cancer (NSCLC) with programmed cell death-ligand 1 (PD-L1) ≥50%,” at the European Society for Medical Oncology (ESMO) Virtual Congress 2020, recently held online.
Libtayo is an engineered human antibody that binds a protein receptor, called PD-1, on the surface of immune T-cells. By doing so, Libtayo prevents this receptor from interacting with PD-L1, a signaling molecule cancer cells produce to avoid being targeted and destroyed by immune cells. Through this mechanism, Libtayo is expected to increase immune cells’ effectiveness at recognizing and destroying cancer cells.
The medication, developed by Regeneron Pharmaceuticals in collaboration with Sanofi, was the first form of immunotherapy to be approved in the U.S. and Europe for the treatment of adults with metastatic or locally advanced cutaneous squamous cell carcinoma (CSCC), a common form of skin cancer, who were not good candidates for surgery or radiation therapy.
Libtayo is currently being investigated as a potential treatment candidate for other types of cancer, including cervical cancer and NSCLC.
EMPOWER-Lung 1 (NCT03088540) is a Phase 3 trial that is assessing the safety and efficacy of Libtayo, compared with platinum-based chemo, when given as a first-line therapy to patients with metastatic or locally advanced NSCLC whose tumors contain PD-L1.
During the study, patients were randomly assigned to receive 350 mg of intravenous (into-the-vein) Libtayo every three weeks for up to 27 months, or four to six cycles of the investigators’ choice of chemo. Those receiving chemotherapy were allowed to switch over to Libtayo after showing signs of disease worsening.
The main goals of the study were to assess if Libtayo could be superior to chemo at prolonging the time patients lived, as well as the time they lived until showing signs of disease progression. Secondary goals included the effects of treatment on patient response rates, response duration, and quality of life.
Consistent with previous data announced in April, new data from EMPOWER-Lung 1 showed that in the overall population of 710 study participants, Libtayo increased the time patients lived from a median of 14.3 to 22.1 months, lowering their risk of death by 32%.
These survival benefits were even stronger in a sub-group of 563 patients whose tumors had more than 50% of PD-L1-positive cells. In this group of patients, Libtayo lowered the risk of death by 43%.
“In new analyses presented at ESMO, Libtayo reduced the risk of death by 43% in patients whose cancer had confirmed PD-L1 expression of 50% or greater. This is notable given that nearly three-quarters of patients crossed over from chemotherapy following disease progression and 12% of patients had pretreated and stable brain metastases,” Ahmet Sezer, MD, associate professor in the department of medical oncology at Başkent University, in Turkey, and a trial investigator who presented the findings at ESMO, said in a press release.
Compared with chemo, Libtayo also lowered the risk of disease progression or death by 41% in the overall population of patients enrolled in the study, and by 46% in the group whose tumors had more than 50% of PD-L1-positive cells.
The percentage of patients who responded to treatment also was higher among those receiving Libtayo. In the overall population, 37% of the patients responded to Libtayo, compared with a response rate of 21% among those receiving chemo. Similar findings were seen in the subset of patients with confirmed PD-L1 tumor levels.
Unlike patients treated with chemo, investigators found that in those on Libtayo, higher response rates were associated with higher levels of PD-L1 in tumor cells. Patients on Libtayo whose tumors had at least 90% of PD-L1-positive cells had response rates of 46%, with their target tumors shrinking by more than 40% after an average of six months of treatment.
In the overall population, those who received Libtayo also had longer treatment responses compared with those treated with chemo (median of 21.0 vs. 6.0 months).
The incidence of severe (grade 3), life-threatening (grade 4), or fatal (grade 5) adverse events was also lower with Libtayo, compared with chemo (37% vs. 49%). However, the percentage of patients who discontinued treatment due to side effects was slightly higher in the Libtayo group (6% vs. 4%). No new safety concerns associated with the use of Libtayo were reported.
“These results support Libtayo as a potential new option for anti-PD-1 monotherapy in first-line advanced non-small cell lung cancer,” Sezer said.
