WCLC 2026, day 2: MRI surveillance without prophylactic cranial irradiation, and two relapse trials at 13.3 and 18.5 months

MRI surveillance without PCI improves cognitive failure-free survival, with no early survival difference

SWOG S1827 MAVERICK, presented by Dr. Chad Rusthoven of the University of Colorado School of Medicine, is an international phase III trial in which 304 patients with limited-stage or extensive-stage SCLC and no brain metastases on MRI after initial therapy were randomised to MRI surveillance alone or MRI surveillance plus prophylactic cranial irradiation (PCI, 25 Gy in 10 fractions). Sites were in the United States, Canada, Mexico, Korea, Chile and Colombia; 68% of patients had limited-stage disease. At a median follow-up of 22 months for living patients, cognitive failure-free survival, the primary endpoint, favoured MRI alone (HR 0.60, 90% CI 0.46–0.78), with no significant interaction by stage or by receipt of immunotherapy. A preliminary overall survival analysis at 128 deaths gave an HR of 0.90 (90% CI 0.67–1.20) for MRI alone; the final analysis follows 190 deaths. Brain metastasis-free survival did not differ significantly (HR 1.25, 90% CI 0.95–1.66), although the slides show more brain metastases with MRI alone (30% versus 15% at 12 months). Grade 3–5 treatment-related adverse events occurred in 0.8% versus 7.9% (p=0.004), including one grade 5 encephalopathy after PCI. In the IASLC release Dr. Rusthoven said: “These results support MRI surveillance alone as the standard of care for patients with SCLC.” The detailed cognitive-function analyses and the final survival result were not presented.

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Tam-Peli adds about four months of median survival over topotecan in relapsed SCLC

TAISHAN-302, presented by Prof. Li Zhang of Sun Yat-sen University Cancer Center, Guangzhou, is a randomised, open-label phase 3 trial of tambotatug pelitecan (Tam-Peli, YL201), an anti-B7-H3 antibody-drug conjugate, against topotecan as second-line treatment for SCLC relapsed after one line of platinum-based therapy, conducted in China. Of 451 patients, 225 received Tam-Peli at 2.0 mg/kg every three weeks and 226 topotecan; the primary endpoint was overall survival. At the 20 May 2026 cut-off, after roughly nine months of follow-up, median overall survival was 13.3 months with Tam-Peli and 9.4 months with topotecan (stratified HR 0.46, 95% CI 0.35–0.62, p<0.0001); the benefit held in patients with brain metastases (HR 0.43). Median progression-free survival was 7.4 versus 2.8 months (HR 0.29, 95% CI 0.23–0.37) and the objective response rate 59.1% versus 9.7%. Grade 3 or higher treatment-related adverse events were fewer with Tam-Peli (46.4% versus 74.7%), with no treatment-related deaths on Tam-Peli; interstitial lung disease or pneumonitis occurred in 4.9% versus 1.4%, none above grade 3. Prof. Zhang said in the release: “TAISHAN-302 is among the first phase III studies of an antibody-drug conjugate to demonstrate statistically significant and clinically meaningful improvements in overall survival, progression-free survival and objective response rate compared with topotecan in relapsed small-cell lung cancer.” Subgroup confidence intervals were not reported, and the survival result is an interim analysis.

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Risvutatug rezetecan reaches a median survival of 18.5 months in relapsed SCLC

ARTEMIS-008 (NCT06498479), presented by Prof. Jie Wang of the Cancer Hospital, Chinese Academy of Medical Sciences, Beijing, is a multicentre, open-label, randomised phase 3 trial of risvutatug rezetecan (Ris-Rez), a B7-H3-directed antibody-drug conjugate, at 8.0 mg/kg every three weeks against topotecan, in SCLC that had progressed on or after platinum-based chemotherapy. All 461 patients were enrolled in China (230 Ris-Rez, 231 topotecan); 80.9% had received a prior PD-(L)1 inhibitor. At the 6 June 2026 cut-off, a pre-planned interim analysis at a median follow-up of 12.2 months, median overall survival was 18.5 months with Ris-Rez and 10.3 months with topotecan (HR 0.46, 95% CI 0.35–0.62, p<0.0001). By blinded independent central review, median progression-free survival was 7.2 versus 3.0 months (HR 0.33, 95% CI 0.25–0.42), the objective response rate 58.3% versus 12.6% and the disease control rate 90.4% versus 60.2%. Grade 3 or higher treatment-related adverse events occurred in 60.9% versus 78.2% and were mainly haematological. The slides add interstitial lung disease in 11.7% versus 1.9%, none of grade 4 or 5. In the IASLC release Prof. Wang said: “Ris-Rez demonstrated a statistically significant and clinically meaningful overall survival benefit over topotecan in patients with SCLC that progressed after platinum-based therapy, with a favorable safety profile.” Confidence intervals for the median survival times and a p-value for progression-free survival were not reported.

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Sacituzumab govitecan plus pembrolizumab misses both primary endpoints in PD-L1-high NSCLC

EVOKE-03/KEYNOTE-D46 (NCT05609968), presented by Dr. Giannis Mountzios of the Henry Dunant Hospital Center, Athens, is an open-label, multicentre phase 3 trial in 620 patients with untreated metastatic NSCLC, a PD-L1 tumour proportion score of at least 50% and no EGFR, ALK or ROS1 alteration, randomised to sacituzumab govitecan plus pembrolizumab or pembrolizumab alone. The dual primary endpoints were progression-free survival by blinded independent central review and overall survival. At the 3 April 2026 cut-off (median follow-up 14.7 months), median progression-free survival was 11.8 months with the combination and 7.7 months with pembrolizumab (HR 0.81, 95% CI 0.66–1.00; one-sided p=0.0252 against a boundary of 0.007 stated in the slides). At the interim overall survival analysis the medians were 21.5 and 22.8 months (HR 1.07, 95% CI 0.85–1.35; p=0.7155). The confirmed objective response rate was 55.6% versus 43.7%. The slides report grade 3 or higher treatment-emergent adverse events in 73.6% versus 45.0%. Dr. Mountzios said in the release: “While the combination of sacituzumab govitecan and pembrolizumab produced a numerically longer progression-free survival and a higher response rate, EVOKE-03/KEYNOTE-D46 did not meet statistical significance for its primary PFS endpoint, and overall survival was not significantly improved at this interim analysis.” Subgroup hazard ratios appear on the slides as images only, and patient-reported outcomes were not presented.

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Ivonescimab prolongs overall survival over pembrolizumab in PD-L1-positive NSCLC

HARMONi-2 (NCT05499390), presented by Prof. Caicun Zhou of Shanghai Pulmonary Hospital, is a randomised phase 3 trial of ivonescimab, a PD-1/VEGF bispecific antibody, against pembrolizumab as first-line monotherapy in 398 patients with treatment-naive, locally advanced or metastatic NSCLC, a PD-L1 tumour proportion score of at least 1% and no EGFR or ALK alteration, enrolled at centres in China (198 ivonescimab, 200 pembrolizumab). Progression-free survival, the primary endpoint, was reported earlier (HR 0.51). This second prespecified interim analysis of overall survival, the key secondary endpoint, used 234 events at a 20 August 2026 cut-off. Median overall survival was 30.75 months with ivonescimab and 22.57 months with pembrolizumab (HR 0.73, 95% CI 0.57–0.95, p=0.009). The hazard ratio was 0.65 in squamous and 0.79 in non-squamous histology, and 0.58 (95% CI 0.38–0.89) at a tumour proportion score of 50% or more against 0.85 (95% CI 0.61–1.18) at 1–49%. Any-grade treatment-related adverse events occurred in 93.4% versus 84.9%, serious ones in 29.9% versus 21.6%, and immune-related adverse events in 34.0% versus 33.7%. In the IASLC release Prof. Zhou said: “Ivonescimab significantly prolonged overall survival versus pembrolizumab in this patient population, with no new safety signals identified relative to the established pembrolizumab safety profile.” Grade 3 or higher adverse event rates, response rates and an updated progression-free survival were not reported.

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Written by the Lung Summit editorial team.