A human monoclonal antibody (mAb), Imfinzi attaches to programmed death-ligand 1 (PD-L1) while Tremelimumab, also a human mAb, hinders cytotoxic T-lymphocyte-associated protein 4’s (CTLA-4) activity.
The randomised, open-label, multi-centre, global Phase III POSEIDON trial compared Imfinzi plus platinum-based chemotherapy or Imfinzi plus tremelimumab and chemotherapy to chemotherapy alone as the first-line treatment.
It enrolled a total of 1,013 metastatic NSCLC patients.
Subjects in the experimental arms received Imfinzi 1,500mg plus up to four cycles of chemotherapy once every three weeks or Imfinzi and tremelimumab 75mg along with chemotherapy.
Subsequently, Imfinzi, or Imfinzi and a single tremelimumab dose every four weeks, were administered as the maintenance treatment.
The subjects in the control arm received up to six cycles of chemotherapy.
According to data from the final analysis of this trial, the Imfinzi, tremelimumab and chemotherapy combination was found to deliver statistically significant and clinically meaningful OS benefit as compared to chemotherapy alone.
Furthermore, this combination treatment also showed a statistically significant improvement in progression-free survival (PFS) as compared to chemotherapy alone, as reported in October 2019.
In an earlier analysis, statistically significant improvement in PFS versus chemotherapy was observed in Imfinzi plus chemotherapy arm but the latest data showed that the OS trend failed to meet statistical significance.
The combination treatments showed a favourable safety profile without any new safety signals.
AstraZeneca Oncology Business Unit executive vice-president Dave Fredrickson said: “We are pleased to see the POSEIDON Phase III trial demonstrate, for the first time, a significant and clinically meaningful overall survival benefit for Imfinzi plus tremelimumab with chemotherapy in metastatic non-small cell lung cancer.
“We’ve seen encouraging uptake of novel combinations in this setting and believe this new approach will add a further option for patients with high unmet medical need.”
Last month, AstraZeneca dosed the first subjects in three clinical trials of monoclonal antibody Fasenra (benralizumab) for the treatment of skin diseases.
In another development, Daiichi Sankyo and AstraZeneca’s datopotamab deruxtecan (Dato-DXd) demonstrated preliminary response and disease control in metastatic triple-negative breast cancer (TNBC) patients with disease progression after standard therapy.
Dato-DXd is a trophoblast cell surface antigen 2 (Trop2) directed antibody-drug conjugate.