OptiTROP-Lung05 NCT06448312
For1L stage IIIB-IV NSCLC, PD-L1 TPS ≥1%, EGFR/ALK wild-type, ECOG 0-1
HR 0.35
95% CI 0.26-0.47, p<0.0001; NR vs 5.7 mo
TL;DRmPFS NR vs 5.7mo, HR 0.35 (0.26-0.47) for sac-TMT + pembro in 1L PD-L1+ NSCLC.
In treatment-naive PD-L1 TPS ≥1% advanced NSCLC without EGFR/ALK alteration, this supports a TROP2 ADC plus pembro as a chemo-free option worth watching; it does not address pts already committed to pembro plus platinum chemo, nor PD-L1-negative disease.
| Arm | PFS events, n (%) | Median PFS, mo (95% CI) | HR (95% CI) |
|---|---|---|---|
| Sac-TMT + Pembro (n=208) | 66 (31.7) | NR (13.6, NE) | 0.35 (0.26, 0.47), p<0.0001 |
| Pembro (n=205) | 128 (62.4) | 5.7 (4.3, 7.0) | n/a |
+3 more figures
| PD-L1 stratum | Sac-TMT + Pembro median, mo | Pembro median, mo | HR (95% CI) |
|---|---|---|---|
| TPS ≥50% | NR (NE, NE) | 9.5 (6.9, 13.8) | 0.47 (0.29, 0.77) |
| TPS 1-49% | NR (11.1, NE) | 4.3 (2.9, 5.5) | 0.28 (0.19, 0.41) |
| Arm | OS events, n (%) | Median OS, mo (95% CI) | HR (95% CI) |
|---|---|---|---|
| Sac-TMT + Pembro (n=208) | 33 (15.9) | NR (NE, NE) | 0.55 (0.36, 0.85) |
| Pembro (n=205) | 54 (26.3) | NR (NE, NE) | n/a |
13 details 3 trials watching
Randomized, multicenter, open-label phase 3 (NCT06448312), 1:1, N=413. Stratified by histology (squamous vs non-squamous), PD-L1 TPS (1-49% vs ≥50%), and ECOG (0 vs 1). Median follow-up 10.5 months at this analysis.
Locally advanced stage IIIB/IIIC or metastatic stage IV NSCLC with no prior systemic antitumor therapy. Required PD-L1 TPS ≥1% by IHC 22C3 central lab, no sensitizing EGFR or ALK alteration, ECOG 0 or 1.
Sac-TMT 4 mg/kg Q2W plus pembrolizumab 400 mg versus pembrolizumab 400 mg Q6W alone, until progression or unacceptable toxicity. Pembro was capped at a maximum of 18 cycles in both arms. One pt in the pembro group never received assigned treatment.
Primary: PFS by BICR. Key secondary: OS. Other secondary: investigator-assessed PFS, ORR, DCR, DOR, safety. The updated efficacy boundary at the actual 194 PFS events was 0.0174 (2-sided).
PFS crossed its boundary at p<0.0001. OS was descriptive at the PFS interim, HR 0.55 (0.36, 0.85) with both medians not reached and only 33 vs 54 deaths.
The pembro-alone control performed as expected for an all-comers TPS ≥1% population, with the TPS ≥50% arm reaching 9.5 mo and the TPS 1-49% arm 4.3 mo, consistent with the KEYNOTE-042 signal that low-expressors gain least from single-agent IO. This is the setting where chemo-IO has historically been chosen, so the trial tests whether an ADC can occupy that slot instead of platinum doublet chemotherapy.
No toxicity data in the source, which is the decisive missing piece for a doublet whose entire premise is avoiding chemotherapy. The comparator is pembro monotherapy rather than the chemo-IO most oncologists actually give at TPS 1-49%, so the PFS gap partly measures a weak control rather than a strong experimental arm.
An HR of 0.35 with a median not reached is a large PFS effect, and the OS point estimate moves in the same direction, but neither settles whether sac-TMT plus pembro beats the regimen it would actually replace. The larger effect in TPS 1-49% (HR 0.28) than TPS ≥50% (HR 0.47) is the expected pattern when the control arm is weakest in the low-expressors, not evidence of a biomarker-selected ADC effect.
CONSORT flow
PFS interim of an open-label phase 3; OS descriptive at 10.5 mo f/u with both medians NR. No safety data in source, and no comparison vs pembro + chemo.
- Benefit vs pembrolizumab plus platinum chemotherapy, the real-world comparator n=614 · primary completion 2028-01 · phase 3 sac-TMT + pembro vs pembro alone, TPS >=50%, OSrecruiting Pembrolizumab With or Without Maintenance Sacituzumab Tirumotecan (Sac-TMT; MK-2870) in Metastatic Squamous Non-small Cell Lung Cancer (NSCLC) [MK-2870-023] Phase 3n=851 · primary completion 2029-01 · 1L sq NSCLC: pembro + platinum backbone, sac-TMT maint
- Safety and ILD rates of sac-TMT combined with pembrolizumab n=30 · primary completion 2026-12 · phase 1 safety/tolerability of sac-TMT + pembro
- Whether the OS signal holds at the final prespecified analysis
📚 Sources · 🐦 2 tweets
Right patient. Right treatment. Right timing.
— Yakup Ergün (@dr_yakupergun) May 30, 2026
The result: curves like these👇#ASCO26 https://t.co/72KByLKz90
🔁REVIEW #ASCO26 #LCSM Oral
— Hidehito HORINOUCHI (@HHorinouchi) May 30, 2026
🔥OptiTROP-Lung05: 1L Sac-TMT + Pembro vs Pembro in PD-L1+ NSCLC
✅mPFS NR vs 5.7m (HR 0.35)
✅ORR 70.2% vs 42.0%
✅OS HR 0.55 (95%CI 0.36-0.85, immature)
🎙️Dr. Caicun Zhou
🔗 https://t.co/DcbK1dGrhO@OncoAlert @Larvol @ASCO @IASLC https://t.co/512k6dZviW pic.twitter.com/Vdo86N50h9
The longer read
The number that will travel from this presentation is HR 0.35, and it deserves a moment of scepticism about what it is measuring. Pembrolizumab monotherapy in an all-comers TPS ≥1% population is a control arm that produces a median PFS in the 5 to 6 month range, which is exactly what happened here (5.7 mo). That is a low bar. The relevant question for a first-line decision is not whether adding a TROP2 ADC beats pembrolizumab alone, but whether it beats pembrolizumab plus platinum doublet chemotherapy, and this trial does not ask that. Until a chemo-IO comparator trial reads out, the magnitude here is best understood as the size of the gap that combination therapy of any kind closes over IO monotherapy in a population where roughly 60% of pts have TPS under 50%.
The PD-L1 subgroup pattern supports that reading rather than complicating it. The effect is larger in TPS 1-49% (HR 0.28, median 4.3 mo in the control) than in TPS ≥50% (HR 0.47, median 9.5 mo in the control). That gradient is what you see whenever a combination is tested against single-agent IO across expression strata: the control arm underperforms most where PD-L1 is lowest, so the ratio widens there. It is not, on this evidence, a signal that TROP2 biology is enriched in low-expressors. A reader tempted to use the 0.28 as a reason to prioritise this regimen specifically in the 1-49% group is reading a property of the comparator as a property of the drug.
Methodologically the design does the important things right and one thing it cannot. PFS was assessed by blinded independent central review, which is the correct mitigation for an open-label trial whose primary endpoint is radiographic, and the efficacy boundary was pre-specified and updated to the actual event count (0.0174 two-sided at 194 events). What blinding cannot fix is the behaviour of pts and investigators who know the assignment, particularly around the timing of scans and the decision to call progression at the margin. With an HR this far from unity that concern is unlikely to explain the result, but it is worth holding for the secondary endpoints.
The overall survival data are genuinely immature and should be treated as directional only. Median follow-up is 10.5 months, both arms have medians not reached, and there are 33 versus 54 events. An HR of 0.55 with a confidence interval reaching 0.85 at this event count is compatible with a wide range of eventual truths, including a substantially smaller benefit once the curves mature and post-progression therapy in the control arm takes effect. Pembro was capped at 18 cycles in both arms, which means the control pts come off IO and become eligible for subsequent lines, and what they receive will shape the final OS read as much as the randomized comparison does.
The largest gap in what was presented is safety. A chemotherapy-free first-line regimen earns its place by being better tolerated than chemo-IO, and no toxicity data appear in this source. TROP2 ADCs as a class carry stomatitis, cytopenias, and interstitial lung disease, and the last of those matters disproportionately when the partner is a checkpoint inhibitor and the tumour is in the lung. Whether this regimen is adoptable rests on numbers that this presentation, as captured, does not provide.