Journal of Clinical Oncology SEPTEMBER 09, 2024

Datopotamab Deruxtecan Versus Docetaxel for Previously Treated Advanced or Metastatic Non-Small Cell Lung Cancer: The Randomized, Open-Label Phase III TROPION-Lung01 Study

Ahn MJ, Tanaka K, Paz-Ares L, et al.

Bottom Line

In patients with previously treated advanced or metastatic non-small cell lung cancer (NSCLC), datopotamab deruxtecan demonstrated a statistically significant improvement in progression-free survival (PFS) compared with docetaxel, particularly in the nonsquamous subgroup, though it did not significantly improve overall survival (OS).

Key Findings

1. Datopotamab deruxtecan (Dato-DXd) resulted in a statistically significant, albeit modest, improvement in progression-free survival (PFS) compared to docetaxel in the overall study population, with a median PFS of 4.4 months versus 3.7 months (hazard ratio [HR], 0.75; 95% confidence interval [CI], 0.62–0.91; P=0.004).
2. In the prespecified subgroup of patients with nonsquamous NSCLC, the benefit was more pronounced, with a median PFS of 5.5 months for Dato-DXd versus 3.6 months for docetaxel (HR, 0.63; 95% CI, 0.51–0.79).
3. Final overall survival (OS) analysis showed no statistically significant difference between the two treatment arms in the overall population, with a median OS of 12.9 months with Dato-DXd compared to 11.8 months with docetaxel (HR, 0.94; 95% CI, 0.78–1.14; P=0.530).
4. Dato-DXd demonstrated a more favorable safety profile regarding grade ≥3 treatment-related adverse events (TRAEs), which occurred in 25.6% of patients in the Dato-DXd group compared to 42.1% in the docetaxel group.

Study Design

Design
RCT
Open-Label
Sample
604
Patients
Duration
9.6-10.9 mo
Median
Setting
Multicenter, Global
Population Adults with stage IIIB/C or IV non-small cell lung cancer (NSCLC) who received at least one prior systemic therapy.
Intervention Datopotamab deruxtecan (6 mg/kg every 3 weeks).
Comparator Docetaxel (75 mg/m2 every 3 weeks).
Outcome Progression-free survival (PFS) by blinded independent central review and overall survival (OS).

Study Limitations

The study failed to meet the dual primary endpoint of improved overall survival in the overall population, limiting the clinical argument for Dato-DXd as a definitive replacement for docetaxel in all-comers.
The efficacy benefit of Dato-DXd was primarily driven by the nonsquamous subgroup, with no clear progression-free or overall survival benefit observed in patients with squamous histology.
The open-label study design may have introduced potential for bias in the assessment of subjective endpoints or clinical management of side effects.
While grade ≥3 TRAEs were lower with Dato-DXd, specific toxicities such as stomatitis (47.5%) and interstitial lung disease/pneumonitis remain important clinical considerations requiring monitoring.

Clinical Significance

While Dato-DXd offers a statistically significant improvement in PFS over docetaxel and a more manageable grade ≥3 toxicity profile in pretreated NSCLC, the lack of significant OS benefit necessitates careful selection of patients—likely favoring those with nonsquamous histology—when considering this therapy in clinical practice.

Historical Context

Docetaxel has long served as the standard-of-care second-line chemotherapy for patients with advanced NSCLC who progress after initial platinum-based treatment; however, its use is often limited by significant toxicities and modest efficacy, prompting the evaluation of newer targeted agents like the TROP2-directed antibody-drug conjugate datopotamab deruxtecan.

Guided Discussion

High-yield insights from every perspective

Med Student
Medical Student

What is the mechanism of action of datopotamab deruxtecan (Dato-DXd), and how does its 'bystander effect' distinguish it from traditional chemotherapy?

Key Response

Dato-DXd is an antibody-drug conjugate (ADC) consisting of a humanized anti-TROP2 IgG1 monoclonal antibody linked to a topoisomerase I inhibitor payload (deruxtecan). Unlike traditional chemotherapy which affects all rapidly dividing cells, ADCs deliver the cytotoxic agent directly to cells expressing the target antigen (TROP2). The 'bystander effect' occurs when the payload is released from the target cell and diffuses into neighboring tumor cells, potentially killing adjacent cells regardless of their target expression, which is a key feature of the deruxtecan-based ADC technology.

Resident
Resident

In the TROPION-Lung01 study, how did the toxicity profile of datopotamab deruxtecan differ from docetaxel, and what are the key adverse events a clinician must monitor for?

Key Response

Datopotamab deruxtecan showed a different safety profile than docetaxel. While docetaxel is associated with higher rates of grade 3 or higher neutropenia and febrile neutropenia, Dato-DXd is more commonly associated with stomatitis (all grades ~47%) and nausea. Critically, clinicians must monitor for interstitial lung disease (ILD)/pneumonitis, a known class effect of deruxtecan ADCs, which occurred in 8% of patients in the Dato-DXd arm (mostly low grade, but including some fatal cases).

Fellow
Fellow

How should the significant progression-free survival (PFS) benefit observed in the nonsquamous subgroup be reconciled with the lack of benefit in the squamous cell carcinoma subgroup in the TROPION-Lung01 trial?

Key Response

The trial demonstrated a clear benefit in nonsquamous NSCLC (PFS HR 0.63), while the squamous subgroup actually trended toward favoring docetaxel (PFS HR 1.38). This suggests a biological divergence in TROP2 dependency or ADC processing between histologies. For a fellow, this underscores the importance of histology-driven treatment selection in the second-line setting and suggests that TROP2 expression levels or internalization rates may differ significantly across NSCLC subtypes.

Attending
Attending

Given that TROPION-Lung01 met its primary endpoint for PFS but failed to demonstrate a statistically significant improvement in overall survival (OS), how does this affect the clinical value proposition of replacing docetaxel as the second-line standard of care?

Key Response

While PFS was significantly improved (especially in nonsquamous patients), the lack of OS benefit (HR 0.94 in the final analysis) creates a clinical dilemma. The attending must weigh the 'quality of life' benefit—derived from a more favorable safety profile (fewer hematologic toxicities) and delayed progression—against the lack of a proven survival advantage. This necessitates a shared decision-making approach, prioritizing either toxicity management or survival outcomes depending on the individual patient's goals.

Scholarly Review

Critical appraisal through the lens of expert reviewers and guideline development

PhD
PhD

The TROPION-Lung01 study utilized a dual primary endpoint (PFS and OS) in an all-comers population. What are the statistical and design implications of the observed heterogeneity in the nonsquamous vs. squamous subgroups for future ADC trial designs?

Key Response

The marked difference in efficacy between histologies suggests that 'all-comer' designs may dilute the treatment effect of ADCs if the target biology varies by subtype. Future research should investigate if TROP2 mRNA or protein expression levels are predictive biomarkers, and whether future Phase III trials should be stratified or exclusively limited to nonsquamous populations. This highlights a need for better patient selection strategies (biomarkers) rather than relying solely on anatomic histology.

Journal Editor
Journal Editor

As a reviewer, how would you address the clinical significance of the primary endpoint 'success' in this trial, given the magnitude of the PFS benefit was only 0.7 months in the intention-to-treat population?

Key Response

A journal editor would flag that while the HR of 0.75 was statistically significant, the median PFS improvement (4.4 vs 3.7 months) is modest. This raises questions about the 'meaningful' clinical benefit. A tough reviewer would also scrutinize whether the nonsquamous subgroup analysis was pre-specified with sufficient power or if it was an exploratory finding used to salvage a trial that was largely negative in the squamous population.

Guideline Committee
Guideline Committee

Should the TROPION-Lung01 data lead to a change in the NCCN or ASCO guidelines for second-line NSCLC, specifically regarding the 'preferred' status of docetaxel?

Key Response

Current guidelines (e.g., NCCN) recommend docetaxel with or without ramucirumab. While Dato-DXd showed improved PFS and better tolerability in nonsquamous patients, the lack of OS benefit makes it difficult to designate it as a superior 'Category 1' recommendation over the existing standard. The committee would likely consider it as a histology-specific option for nonsquamous patients who are poor candidates for the hematologic toxicity of docetaxel, but may wait for further data on subsequent ADCs before a full-scale replacement of docetaxel.

Clinical Landscape

Noteworthy Related Trials

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KEYNOTE-010

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Comparator

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Endpoint

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2017

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Atezolizumab

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Endpoint

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2021

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Tested

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Population

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Comparator

None (single arm)

Endpoint

Objective response rate

Key result: Trastuzumab deruxtecan showed durable antitumor activity with an objective response rate of 55% in patients with HER2-mutant NSCLC.

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