Abstract CT253: Results from KEYNOTE-B99: Phase 2 study of first-line (1L) pembrolizumab (pembro) plus investigational agents and chemotherapy (chemo) for extensive-stage small-cell lung cancer (ES-SCLC)
Bibliographic record
Abstract
Abstract Background: ES-SCLC is an aggressive cancer with substantial mortality. Current 1L treatments include anti-PD-(L)1 + etoposide-platinum chemo (EP), but with minimal improvements in OS vs chemo. In the phase 3 KEYNOTE-604 study, pembro + EP significantly improved PFS (P = 0.0023) but not OS vs placebo + EP; ORR was also improved (71% vs 62%). We present data from the phase 2 KEYNOTE-B99 study (NCT04924101) of 1L pembro + investigational agents (MK-4830, anti-ILT4; boserolimab, anti-CD27; or lenvatinib), and EP for ES-SCLC. Methods: In this open-label platform study, patients (pts) were aged ≥18 y with previously untreated histologically or cytologically confirmed stage IV ES-SCLC (per AJCC v8) and ECOG PS 0 or 1. Pts were randomized 1:1:1 to receive MK-4830 800 mg Q3W (35 cycles; arm A), boserolimab 30 mg Q6W (18 cycles; arm B), or lenvatinib 8 mg (induction)/20 mg (maintenance) QD (arm C). All pts received pembro 200 mg Q3W (35 cycles) + etoposide 100 mg/m2 Q3W and cisplatin 75 mg/m2 Q3W or carboplatin AUC 5 mg/mL/min Q3W (4 cycles). Primary endpoints were ORR and PFS at 6 mo, both assessed per RECIST v1.1 by BICR. Secondary endpoints included DOR, PFS, OS, and safety. Results: 122 pts received ≥1 dose of study treatment (arm A, 43; B, 41; C, 38). At data cutoff (Sep 15, 2023), median follow-up was 14.1 (range, 6.1-25.7) mo. ORR was 65%, 71%, and 74% in arms A, B, and C, respectively; median DOR was 6.8, 4.7, and 7.1 mo. 6-mo PFS rates were 45%, 38%, and 54%, respectively (Table). AEs (any cause) occurred in 98% of pts in arm A and all pts in arms B and C; most commonly neutropenia and anemia. Serious AEs occurred in 30%, 37%, and 55%; grade ≥3 AEs in 86%, 83%, and 87% of pts; and grade 5 AEs in 5%, 7%, and 21%, respectively. Conclusions: 1L ES-SCLC treatment with pembro + EP and MK-4830, boserolimab, or lenvatinib was associated with similar antitumor activity as in KEYNOTE-604 with pembro + EP. No new safety signals were identified. TABLE 1. NAND Group A MK-4830 + Pembro + EP(n = 43) Group B boserolimab + Pembro + EP(n = 41) Group C Lenvatinib + Pembro + EP(n = 38) ORR (95% CI), % 65.1 (49.1-79.0) 70.7 (54.5-83.9) 73.7 (56.9-86.6) Median DOR (range), mo 6.8 (2.4-13.9) 4.7 (1.4+ to 16.4+) 7.1 (1.8 to 18.4+) PFS - 6-mo PFS rate (95% CI), % 45.2 (29.9-59.4) 37.8 (22.7-52.7) 54.2 (35.8-69.4) - Median PFS (95% CI), mo 5.5 (4.2-8.3) 5.5 (4.0-6.7) 7.2 (5.4-NR) Median OS (95% CI), mo 15.5 (8.3-NR) NR (13.2-NR) 15.8 (7.2-NR) ‘+’, no PD at the time of last disease assessment. NR, not reached. Citation Format: Delvys Rodríguez-Abreu, Maximillian Hochmair, Byoung Chul Cho, Tibor Csőszi, Talia Shentzer Kutiel, Veronika Müller, Myung-Ju Ahn, Dariusz Kowalski, Michele Maio, Vladimir Moiseyenko, Alejandro Navarro, Jianxin Niu, Andrea S. Fung, Carolin Lips, Heng Zhou, Bin Zhao, Humberto Lara-Guerra, Nir Peled. Results from KEYNOTE-B99: Phase 2 study of first-line (1L) pembrolizumab (pembro) plus investigational agents and chemotherapy (chemo) for extensive-stage small-cell lung cancer (ES-SCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT253.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".