REZILIENT3 Key Takeaways
Design
Randomized, open-label Phase 3 (N=285): zipalertinib plus platinum-pemetrexed versus platinum-pemetrexed alone, 1:1, in previously untreated non-squamous EGFR exon 20 insertion NSCLC. Primary endpoint progression-free survival by blinded independent central review. Full study design, population and crossover →
Topline result — 12 August 2026
The trial met its primary PFS endpoint at a planned interim analysis, and the Independent Data Monitoring Committee recommended unblinding. No median PFS, hazard ratio, confidence interval, p-value or response rate was disclosed. Full results are to be submitted for presentation at an upcoming international medical conference.Topline only — no numeric results released (Taiho Oncology / Cullinan Therapeutics press release, 12 Aug 2026)
Safety
The sponsors reported only that “observed safety for the zipalertinib containing arm was manageable.” No adverse-event rates were disclosed. (Taiho / Cullinan, 12 Aug 2026)
Regulatory status
Zipalertinib is investigational and has not been approved by any health authority. It is an oral, irreversible, mutant-selective EGFR tyrosine kinase inhibitor (formerly CLN-081 / TAS6417) developed by Taiho Pharmaceutical with Cullinan Therapeutics. It holds US FDA Breakthrough Therapy Designation for previously treated EGFR ex20ins NSCLC after platinum-based chemotherapy — not for the first-line setting REZILIENT3 studies. On the back of this interim analysis the sponsors stated that, “pending discussions with the U.S. Food and Drug Administration (FDA),” they “plan to pursue U.S. regulatory approval for this combination regimen in the first-line setting.” That is a stated intention: no application has been submitted for this combination and no approval exists. (Taiho / Cullinan, 12 Aug 2026)
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Top KOLs Discussing REZILIENT3 and Zipalertinib
Marcelo Corassa, MD served as the ASCO 2025 discussant for the REZILIENT-1 oral abstract session. Replying to Chul Kim, MD on the agents in development for EGFR exon 20 insertion and HER2-mutant NSCLC, he wrote — about the oral-TKI class, before any REZILIENT3 readout existed:
This is a tough setting. Rare alterations. Toxic drugs. It is nice to see that oral TKIs can finally play a role here without overwhelming toxicity. https://t.co/mri5AwyDGu
— Marcelo Corassa, MD. (@MarceloCorassa) 2025-06-01
How Oncologists Read the REZILIENT3 Topline
Two threads run through the clinical reaction. The first is that this is the third randomised Phase 3 trial to improve PFS over platinum doublet chemotherapy alone in first-line EGFR exon 20 insertion NSCLC, after PAPILLON (amivantamab plus chemotherapy) and WU-KONG28 (sunvozertinib monotherapy). The second is that none of the three has yet demonstrated a clear overall survival benefit, and no head-to-head comparison between them exists — a point Dr. Garitaonaindia makes explicitly above. REZILIENT3 overall survival data remain immature; the study continues to follow patients. Full results are to be presented at a future medical conference.
Sources: Taiho Oncology / Taiho Pharmaceutical / Cullinan Therapeutics topline release, 12 Aug 2026 · PAPILLON and WU-KONG28 comparators as cited in the 1L Landscape section below.
REZILIENT Programme Key Slides & Visuals
Top Physician Posts on Zipalertinib
About the REZILIENT3 Trial
EGFR exon 20 insertion mutations account for a small minority of EGFR-mutant non-small cell lung cancer and have historically been insensitive to the classical EGFR tyrosine kinase inhibitors used for exon 19 deletions and L858R. Until amivantamab plus chemotherapy was established in the first-line setting by PAPILLON, platinum-doublet chemotherapy alone was the standard of care.
Zipalertinib (formerly CLN-081 / TAS6417) is an oral, irreversible, mutant-selective EGFR tyrosine kinase inhibitor built on a pyrrolopyrimidine scaffold designed to hit exon 20 insertion variants while relatively sparing wild-type EGFR. REZILIENT3 is the confirmatory Phase 3 study that moves it into the first-line setting, layered onto platinum-pemetrexed chemotherapy rather than replacing it.
The 12 August 2026 announcement was qualitative throughout — it named the endpoint and the IDMC unblinding recommendation but released no efficacy or safety figures.
Today in partnership with @TaihoOncology and Taiho Pharmaceutical, we announced that our Phase 3 REZILIENT3 trial in patients with NSCLC harboring EGFR ex20ins mutations met its primary endpoint at a planned interim analysis. Learn more: https://t.co/egqUPaGsRf https://t.co/x4ahZAwZmN
— Cullinan Therapeutics (@CullinanTx) 2026-08-12
REZILIENT3 Methodology & What Has Been Reported
Study Design
Randomized, controlled, open-label, global multi-centre Phase 3 trial with a Part A safety lead-in and a randomized Part B. (ClinicalTrials.gov)
Population
Previously untreated locally advanced or metastatic non-squamous NSCLC with documented EGFR exon 20 insertion; ECOG PS 0-1; stable or treated brain metastases allowed. N=285. (ClinicalTrials.gov)
Interventions
Zipalertinib orally twice daily plus pemetrexed and carboplatin or cisplatin (21-day cycles, platinum up to 4 cycles) versus pemetrexed and platinum alone, randomized 1:1. (ClinicalTrials.gov)
Endpoints
Primary: PFS by blinded independent central review per RECIST v1.1, plus safety. Secondary: ORR, DCR, DoR, intracranial ORR and DoR, and overall survival. (ClinicalTrials.gov)
Crossover
Patients on the chemotherapy-only arm with BICR-confirmed progression may cross over to zipalertinib monotherapy. (ClinicalTrials.gov)
Sponsor / development
Taiho Oncology, Inc. is the sponsor, developing zipalertinib with Cullinan Therapeutics, Inc. in the US and with Taiho Pharmaceutical Co., Ltd.
Progression-free survival — primary endpoint MET, no numbers released
REZILIENT3 met its primary PFS endpoint at a planned interim analysis. The sponsors' exact wording: the study “demonstrated a statistically significant and clinically meaningful improvement in PFS in the zipalertinib containing arm,” and “based on these data, the Independent Data Monitoring Committee recommended unblinding the study.”
No median PFS, hazard ratio, 95% CI, p-value, objective response rate or duration of response has been disclosed for either arm. KOL Pulse will not publish estimated or inferred figures. Full results are to be submitted for presentation at an upcoming international medical conference, and the sponsors have said they plan to pursue US regulatory approval for the combination in the first-line setting pending discussions with the FDA.
Endpoint met at interim · efficacy figures pending Source: Taiho Oncology / Cullinan Therapeutics press release, 12 Aug 2026Safety
The only safety statement released is that “observed safety for the zipalertinib containing arm was manageable.” No adverse-event rates, grade 3+ rates or discontinuation rates have been reported for REZILIENT3. The adverse-event profile observed with single-agent zipalertinib in REZILIENT-1 is summarised below and should not be read as REZILIENT3 safety data.
Source: Taiho Oncology / Cullinan Therapeutics press release, 12 Aug 2026REZILIENT-1: the Phase 2b Data Behind Zipalertinib
REZILIENT-1 (NCT04036682) is a separate Phase 1/2 trial. Its Phase 2b portion tested zipalertinib monotherapy at 100 mg twice daily in patients already treated with platinum-based chemotherapy, with or without amivantamab — a later line and a different regimen from REZILIENT3. Helena A. Yu, MD presented these data at ASCO 2025 (Abstract 8503) with simultaneous publication in the Journal of Clinical Oncology. These figures are REZILIENT-1 results and are not REZILIENT3 results.
| Population | N | Confirmed ORR (95% CI) | DCR (95% CI) | Median DoR (95% CI) |
|---|---|---|---|---|
| Primary efficacy population | 176 | 35.2% (28.2-42.8) | 89.2% (83.7-93.4) | 8.8 mo (8.3-12.7) |
| Prior platinum chemotherapy only | 125 | 40.0% (31.3-49.1) | 88.8% (81.9-93.7) | 8.8 mo (8.3-12.7) |
| Prior amivantamab (all) | 51 | 23.5% (12.8-37.5) | 90.2% (78.6-96.7) | 8.5 mo (4.2-14.8) |
| Prior amivantamab only | 30 | 30.0% (14.7-49.4) | 96.7% (82.8-99.9) | 14.7 mo (4.2-NE) |
| Prior amivantamab + other ex20ins agent | 21 | 14.3% (3.0-36.3) | 81.0% (58.1-94.6) | 4.2 mo (3.9-NE) |
| Baseline brain metastases (systemic response) | 68 | 30.9% (20.2-43.3) | 88.2% (78.1-94.8) | 8.3 mo (4.2-9.9) |
REZILIENT-1 safety (zipalertinib monotherapy, N=244)
Grade 3 or higher treatment-related adverse events occurred in 29.5% of patients (72/244). The most common grade 3+ events were anaemia (7.0%), pneumonitis (2.5%), rash (2.5%), ALT increased (2.0%), diarrhoea (2.0%) and platelet count decreased (2.0%). Treatment discontinuation due to drug-related adverse events occurred in 8.2% (20/244), and fatal treatment-related events in 0.8% (2 patients: one pneumonitis, one hypoxia). The most frequent any-grade events were paronychia (38.5%), rash (30.3%), dermatitis acneiform (24.6%), dry skin (24.6%) and diarrhoea (21.7%).
Monotherapy safety, REZILIENT-1 — not REZILIENT3 Source: Piotrowska Z, et al. J Clin Oncol 2025;43(21):2387-2397 (DCO 10 Dec 2024)Dr. @HelenaYu923 at #ASCO25 with results from REZILIENT1 of zipalertinib in #EGFR exon 20 NSCLC. RR 35% with efficacy after other exon 20 directed therapy like amivantamab. 39% paronychia but none grade 3. https://t.co/UpzXUaXNza
— Stephen V Liu, MD (@StephenVLiu) 2025-06-01
First-Line EGFR Exon 20 Insertion NSCLC: the Randomized Phase 3 Landscape
REZILIENT3 enters a first-line setting that already has a randomized winner and a randomized failure. The table below reports only figures verified against the primary publications. REZILIENT3's own efficacy figures are not yet public, so it cannot be compared with these regimens.
| Trial | Regimen vs control | Median PFS | HR (95% CI) | ORR | Source |
|---|---|---|---|---|---|
| PAPILLON | Amivantamab + chemo vs chemo | 11.4 vs 6.7 mo | 0.395 (0.30-0.53), P<0.001 | 73% vs 47% (BICR) | NEJM 2023;389:2039-51 |
| WU-KONG28 | Sunvozertinib vs chemo | 10.3 vs 7.5 mo | 0.65 (0.50-0.85), P=0.0008 | 58.9% vs 31.1% (confirmed, BICR) | NEJM 2026 / ASCO 2026 LBA8500 |
| EXCLAIM-2 | Mobocertinib vs chemo | 9.6 vs 9.6 mo | Did not demonstrate superiority | — | JCO 2025;43:1553-63 |
| REZILIENT3 | Zipalertinib + chemo vs chemo | Primary PFS endpoint met at planned interim analysis — no figures disclosed | Taiho / Cullinan, 12 Aug 2026 | ||
$CGEM $AVBP benchmarks in 1st-line EGFR ex20ins lung cancer https://t.co/IpSRuhfJle
— Jacob Plieth (@JacobPlieth) 2026-08-13
REZILIENT3 and Zipalertinib in the News
REZILIENT3 FAQ
Did the REZILIENT3 trial meet its primary endpoint?
Yes. On August 12, 2026, Taiho Oncology, Cullinan Therapeutics and Taiho Pharmaceutical announced that REZILIENT3 (NCT05973773) met its primary endpoint of progression-free survival at a planned interim analysis, and that the Independent Data Monitoring Committee recommended unblinding the study.
What were the REZILIENT3 results - what is the hazard ratio and median PFS?
No numeric results have been released. The August 12, 2026 topline announcement disclosed no median PFS, hazard ratio, confidence interval, p-value or response rate for either arm. The companies said full results will be submitted for presentation at an upcoming international medical conference. Any figure circulating for REZILIENT3 efficacy is not sourced to the sponsors.
Is zipalertinib FDA approved?
No. Zipalertinib is investigational and has not been approved by any health authority. It is an oral, irreversible, mutant-selective EGFR tyrosine kinase inhibitor (formerly CLN-081 / TAS6417) developed by Taiho Pharmaceutical with Cullinan Therapeutics. It holds US FDA Breakthrough Therapy Designation for previously treated EGFR exon 20 insertion NSCLC after platinum-based chemotherapy, not for the first-line setting studied in REZILIENT3. Following the interim analysis the sponsors said they plan to pursue US regulatory approval for the combination in the first-line setting pending discussions with the FDA - a stated intention, not a submission or an approval.
How is REZILIENT3 different from REZILIENT-1?
They are different trials in different lines of therapy. REZILIENT-1 (NCT04036682) is a Phase 1/2 trial whose Phase 2b portion tested zipalertinib monotherapy in patients already treated with platinum-based chemotherapy with or without amivantamab; it reported a confirmed objective response rate of 35.2% (95% CI, 28.2-42.8) in 176 patients. REZILIENT3 (NCT05973773) is a randomized Phase 3 trial testing zipalertinib added to platinum-doublet chemotherapy in previously untreated (first-line) patients. REZILIENT-1 response data must not be read as REZILIENT3 results.
How does REZILIENT3 compare with PAPILLON and the other first-line exon 20 insertion trials?
PAPILLON established amivantamab plus chemotherapy as a first-line standard, with median PFS 11.4 versus 6.7 months (HR 0.395; 95% CI, 0.30-0.53; P<0.001) (NEJM 2023). WU-KONG28 reported first-line sunvozertinib median PFS 10.3 versus 7.5 months (HR 0.65) (NEJM 2026), while EXCLAIM-2 showed first-line mobocertinib did not improve on chemotherapy (median PFS 9.6 versus 9.6 months) (JCO 2025). REZILIENT3 has reported only that it met its PFS endpoint - no numbers - so no cross-trial comparison with these regimens is possible yet.
Key KOL Sentiments — Zipalertinib & the REZILIENT Programme
Compiled and reviewed by the KOL Pulse research team, led by Brian Shields, Founder, KOL Pulse. Every numeric claim on this page is sourced to the primary publication, sponsor press release or ClinicalTrials.gov record cited beside it. Last updated 2026-08-14.