Setidegrasib Demonstrates Clinical Activity and Manageable Safety in KRAS G12D+ NSCLC

Data from a phase 1 study (NCT05382559) presented at the 2026 European Lung Cancer Congress (ELCC) and published in The New England Journal of Medicine indicate that setidegrasib, a first-in-class protein degrader, yielded significant antitumor activity with a tolerable safety profile in patients with KRAS G12D-mutant non–small cell lung cancer (NSCLC).^1,2

Managing the Toxicity Profile: A Focus on Infusion-Related Reactions

To provide a nursing perspective, the primary takeaway from the safety data is the prevalence and management of infusion-related reactions (IRRs). The study’s primary end point was safety, and while treatment-related adverse events (TRAEs) were nearly universal at 97.8% (n = 44), the majority were grade 1 or 2.

• Infusion-Related Reactions: Occurred in 78% of patients.
• Clinical Presentation: Most IRRs were low grade, occurred during the first infusion, and were successfully managed with standard protocols.
• Severe Toxicity: Grade 3 or higher TRAEs occurred in only 13.3% (n = 6) of patients, with serious TRAEs reported in 6.7% (n = 3).
• Discontinuation: Notably, no TRAEs led to treatment discontinuation or patient death.

Efficacy and Response Durability

In 45 evaluable patients with NSCLC, the overall response rate (ORR) was 35.8%. When stratified by treatment history and smoking status, the data showed:

• Second- or Third-Line Patients: 37.5% ORR.
• Light or Nonsmokers: 47.1% ORR.

The median duration of response (DOR) has not yet been reached for the general cohort or those in the second- and third-line settings. However, in light or nonsmokers, the median DOR was 9.7 months. Exploratory data for progression-free survival (PFS) in the second- and third-line setting reached a median of 11.2 months (95% CI, 5.6-NE).

Understanding Targeted Protein Degradation

Unlike traditional small-molecule inhibitors that block oncogenic proteins, setidegrasib utilizes a mechanism known as proteolysis-targeting chimera (PROTAC).

Because KRAS G12D lacks the reactive cysteine residue found in KRAS G12C, it has historically been difficult to inhibit. Setidegrasib bypasses this by forming a ternary complex between the KRAS G12D protein and the VHL E3 ligase. This marks the protein for ubiquitination and subsequent degradation by the proteasome. By eliminating the protein entirely, the agent effectively shuts down downstream signaling.

Biomarkers and Immunomodulatory Effects

The study confirmed target engagement through circulating tumor DNA (ctDNA) and tumor biopsies.

• Protein Degradation: Biopsies showed a median KRAS G12D protein degradation of 70.6%.
• ctDNA Correlation: Patients achieving a 50% decrease in variant allele frequency (VAF) in ctDNA saw a median PFS of 9.6 months, compared with 2.6 months for those with a less than 50% decrease.

Biopsies also revealed increased intratumoral CD8+ T-cell infiltration. This suggests that setidegrasib may relieve immune suppression within the tumor microenvironment, potentially "priming" the tumor for better responses to immunotherapy.

Nursing Implications and Future Directions

The recommended phase 2 dose (RP2D) has been established at 600 mg administered intravenously weekly. While doses up to 800 mg were tested, they were deemed clinically infeasible for nursing administration due to low solubility requiring excessive volumes and prolonged infusion times.

"The fact that we're relieving the immune suppression probably helps the T-cell infiltration," noted lead study author Philippe Cassier, MD, PhD, of Centre Léon Bérard, in a presentation during the meeting.

A phase 3 trial evaluating setidegrasib as monotherapy is currently advancing. Additionally, researchers are investigating the agent in combination with immune checkpoint inhibitors in the first-line setting, where its immunomodulatory effects may be most impactful.

References

1. Cassier P. Efficacy and safety of setidegrasib in patients with advanced NSCLC with KRAS G12D mutation. Presented at: 2026 ELCC; March 25–28, 2026; Copenhagen, Denmark. Abstract 1O.
2. Park W, Kasi A, Spira A, et al. Setidegrasib in Advanced Non–Small-Cell Lung Cancer and Pancreatic Cancer. N Engl J Med. Published online ahead of print March 25, 2026. doi:10.1056/NEJMoa2600752