INSIGNA Trial Overview and Objectives

The INSIGNA (EA5163/S1709, NCT03793179) trial, sponsored by the ECOG-ACRIN Cancer Research Group under the NCI, is a Phase 3, randomized clinical trial conducted in patients with stage IV non-squamous NSCLC. The trial aims to determine whether a sequential strategy of administering pembrolizumab (Keytruda, an anti-PD-1 monoclonal antibody) as a first-line monotherapy, followed by the addition of chemotherapy upon progression, is non-inferior to the standard strategy of administering first-line immuno-chemotherapy combination therapy in patients with a PD-L1 tumor proportion score (TPS) of 1% or greater. Patients with EGFR, ALK, ROS1, or BRAF V600E driver mutations are excluded, and only adult patients with an ECOG performance status of 0-1 are eligible.

Three Treatment Arms and Key Endpoints

The trial consists of three treatment arms. Arm A involves the administration of pembrolizumab monotherapy followed by the addition of pemetrexed and carboplatin chemotherapy upon progression. Arm B follows the same initial monotherapy approach but transitions to a combination therapy of pembrolizumab, pemetrexed, and carboplatin upon progression. Arm C (the control arm) involves the administration of first-line pembrolizumab, pemetrexed, and carboplatin combination therapy followed by pembrolizumab and pemetrexed maintenance therapy, which is the current standard of care. The primary endpoint is the comparison of overall survival (OS) between the experimental arms (A and B) and the control arm (C). Secondary endpoints include progression-free survival (PFS) according to RECIST 1.1 criteria, objective response rate (ORR), safety assessment, and subgroup analysis of patients with a PD-L1 TPS of 50% or greater.

Market Context: Keytruda's $31.7 Billion in Revenue and Patent Cliff

Merck's (MRK) Keytruda generated $31.7 billion in annual revenue in 2025 and remains the world's top-selling cancer drug. The NSCLC indication accounts for approximately 37% of the overall PD-1/PD-L1 inhibitor market, and the global NSCLC treatment market is projected to grow from approximately $42 billion in 2025 to $70.8 billion in 2030. However, the key U.S. patent for Keytruda is set to expire in 2028, and several companies, including Samsung Bioepis and Amgen, are conducting biosimilar clinical trials. If INSIGNA demonstrates the non-inferiority of the monotherapy strategy, it could provide clinical evidence to support an increase in the proportion of patients receiving monotherapy in the biosimilar transition period, while also reducing chemotherapy costs.

Competitive Landscape and Differentiation of Treatment Strategies

In the first-line NSCLC immunotherapy market, Keytruda competes with nivolumab (Opdivo, Bristol-Myers Squibb/BMY), atezolizumab (Tecentriq, Roche/RHHBY), durvalumab (Imfinzi, AstraZeneca/AZN), and cemiplimab (Libtayo, Regeneron/REGN and Sanofi/SNY). According to a network meta-analysis, the combination of pembrolizumab or cemiplimab with chemotherapy achieved the highest OS, while the combination of nivolumab or atezolizumab with bevacizumab and chemotherapy showed the best PFS. In this competitive landscape, INSIGNA is the first large-scale Phase 3 trial to evaluate whether a sequential strategy of administering immunotherapy first, followed by the addition of chemotherapy as needed, can achieve at least equivalent survival benefits while reducing toxicity.

Current Status and Key Points to Watch

The INSIGNA trial is currently in the active, not recruiting phase, with follow-up ongoing at multiple academic centers in the United States. The OS data maturity is expected in 2028 or later. If monotherapy is shown to be effective in patients with a PD-L1 TPS of 1-49%, it could open up new treatment options for patients with moderate PD-L1 expression, for whom combination chemotherapy is currently considered essential. As the trial is not sponsored by a pharmaceutical company but is led by the NCI/ECOG-ACRIN, it is expected to provide unbiased evidence regarding treatment sequencing.