Two-year update from KEYNOTE-799: Pembrolizumab plus concurrent chemoradiation therapy (cCRT) for unresectable, locally advanced, stage III NSCLC

8508

Background: Primary analysis (database cutoff, Oct 28, 2020) of the global KEYNOTE-799 study (NCT03631784) in patients (pts) with unresectable, locally advanced stage III NSCLC, showed that pembrolizumab (pembro; anti–PD-1) plus cCRT resulted in an ORR of 70.5% in cohort A (n = 112; squamous and nonsquamous) and 70.6% in cohort B (n = 102; nonsquamous only) and grade ≥3 pneumonitis in 9 (8.0%) and 7 (6.9%) pts, respectively. We present updated outcomes with 1 y of additional follow-up. Methods: In this nonrandomized, phase 2 study, eligible pts were aged ≥18 y with previously untreated, unresectable, pathologically confirmed, stage IIIA-C NSCLC with measurable disease per RECIST v1.1. Pts in cohort A (squamous and nonsquamous) received carboplatin AUC 6 plus paclitaxel 200 mg/m2 and pembro 200 mg for one 3-wk cycle, followed by carboplatin AUC 2 plus paclitaxel 45 mg/m2 QW for 6 wks plus 2 cycles of pembro 200 mg Q3W plus standard thoracic radiotherapy (TRT). Pts in cohort B (nonsquamous) received 3 cycles of cisplatin 75 mg/m2, pemetrexed 500 mg/m2, and pembro 200 mg Q3W plus standard TRT in cycles 2 and 3. All pts received 14 additional cycles of pembro 200 mg Q3W. Primary endpoints were ORR per RECIST v1.1 by blinded independent central review (BICR) and the incidence of grade ≥3 pneumonitis (per NCI CTCAE v4.0). Results: Of 216 pts enrolled in this study, 112 in cohort A and 102 in cohort B received treatment. Median (range) time from first dose to database cutoff (Oct 18, 2021) was 30.2 (25.3–35.5) mo in cohort A and 25.4 (14.5–35.2) mo in cohort B. ORR (95% CI) was 71.4% (62.1%–79.6%) in cohort A and 75.5% (66.0%–83.5%) in cohort B. Median duration of response (DOR) and OS were not reached (NR) in both cohorts; median PFS was 30.6 mo in cohort A, and NR in cohort B (Table). ORR was 66.7% in pts with PD-L1 TPS <1% and 77.3% in pts with PD-L1 TPS ≥1% in cohort A and 78.6% and 72.5%, respectively, in cohort B. ORR was similar by histology (squamous, 72.0%; nonsquamous, 74.1%). Grade ≥3 pneumonitis occurred in 16 pts (7.5%) overall; 9 pts (8.0%) in cohort A and 7 (6.9%) in cohort B. Treatment-related grade ≥3 AEs occurred in 64.3% and 51.0% of pts in cohort A and B, respectively. Conclusions: With the accrual of additional responses after >2 y of follow-up, pembro plus cCRT continues to demonstrate robust and durable responses, regardless of PD-L1 TPS and tumor histology, promising survival outcome and manageable safety in pts with previously untreated, locally advanced stage III NSCLC. Clinical trial information: NCT03631784. [Table: see text]

DUART: durvalumab after radiotherapy in patients with unresectable, stage III NSCLC who are ineligible for chemotherapy

Consolidation durvalumab is standard of care in patients with unresectable, stage III non-small-cell lung cancer (NSCLC) without disease progression following chemoradiotherapy (the 'PACIFIC regimen'). However, many patients with poor performance status, older age or comorbidities may be ineligible for chemotherapy due to expected high toxicity. These patients typically receive radiotherapy alone, with poor survival outcomes. Based on the PACIFIC trial data, and the strong biological rationale for combining radiotherapy with anti-programmed cell death ligand-1 therapy, durvalumab following radiotherapy could provide additional survival benefit versus radiotherapy alone. Here, we describe the DUART trial, a Phase II, open-label, single-arm study assessing the safety and tolerability of durvalumab following radiotherapy in patients with unresectable, stage III NSCLC who are ineligible for chemotherapy (ClinicalTrials.gov Identifier: NCT04249362).

TAXOMET: A French Prospective Multicentric Randomized Phase II Study of Docetaxel Plus Metformin Versus Docetaxel Plus Placebo in Metastatic Castration-Resistant Prostate Cancer

BACKGROUND

Docetaxel (DOCE) is a standard of care in metastatic castration-resistant prostate cancer (mCRPC). Several retrospective studies suggested a decrease in Prostate Cancer incidence and mortality with metformin (MET). MET has also demonstrated anti-tumor activity in Prostate Cancer preclinical models, with increased apoptosis when added to DOCE. We aimed at exploring the role of MET in combination with DOCE in mCRPC.

PATIENTS AND METHODS

Non-diabetic mCRPC patients were randomly assigned to receive DOCE 75 mg/m² every 21 days + prednisone (5 mg. BID) with either MET 850 mg BID (D+M) or placebo (D+P) up to 10 cycles. Prostate-Specific Antigen (PSA) response ≥50% from baseline was the primary end point. Secondary end points included objective response rate (ORR), progression-free survival (PFS), overall survival (OS), toxicity and quality of life (QoL).

RESULTS

Out of 99 patients were randomized (D+M = 50; D+P = 49) in 10 French centers. The median follow-up was 86 (IQR 73-88) months. The PSA-response rate reached 66% in the D+M arm, but was not different from that observed in the D+P arm (63%, P = 0,94). In the D+M and D+P arms, the ORR was 28% and 24%, the median PFS was 7.8 and 6.0 months and the median OS was 27 and 20 months (ns), respectively. Diarrhea grade I to II was more frequent in the MET arm (66% vs. 43%). No impairment of QoL was observed.

CONCLUSION

MET addition failed to improve the standard DOCE regimen in mCRPC. Further research targeting tumor cell metabolism should be performed.

Pembrolizumab Plus Concurrent Chemoradiation Therapy in Patients With Unresectable, Locally Advanced, Stage III Non-Small Cell Lung Cancer: The Phase 2 KEYNOTE-799 Nonrandomized Trial

IMPORTANCE

Administration of pembrolizumab plus concurrent chemoradiation therapy (cCRT) may provide treatment benefit to patients with locally advanced, stage III non-small cell lung cancer (NSCLC).

OBJECTIVE

To evaluate treatment outcomes and safety of pembrolizumab plus cCRT in stage III NSCLC.

DESIGN, SETTING, AND PARTICIPANTS

The phase 2, nonrandomized, 2-cohort, open-label KEYNOTE-799 study enrolled patients between November 5, 2018, and July 31, 2020, from 52 academic facilities and community-based institutions across 10 countries. As of October 28, 2020, median (range) follow-up was 18.5 (13.6-23.8) months in cohort A and 13.7 (2.9-23.5) months in cohort B. Of 301 patients screened, 216 eligible patients with previously untreated, unresectable, and pathologically/radiologically confirmed stage IIIA/IIIB/IIIC NSCLC with measurable disease per Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST v1.1) were enrolled.

INTERVENTIONS

Patients in cohort A (squamous/nonsquamous) received 1 cycle (3 weeks) of carboplatin (area under the curve [AUC] 6 mg/mL/min), paclitaxel (200 mg/m2), and pembrolizumab (200 mg), followed by carboplatin (AUC 2 mg/mL/min) and paclitaxel (45 mg/m2) once weekly for 6 weeks and 2 cycles of pembrolizumab plus standard thoracic radiotherapy. Patients in cohort B (nonsquamous) received 3 cycles of cisplatin (75 mg/m2), pemetrexed (500 mg/m2), and pembrolizumab (200 mg) every 3 weeks and thoracic radiotherapy in cycles 2 and 3. Patients received 14 additional cycles of pembrolizumab.

MAIN OUTCOMES AND MEASURES

Coprimary end points were objective response rate per RECIST v1.1 by blinded independent central review and incidence of grade 3 to 5 pneumonitis.

RESULTS

A total of 112 patients received treatment in cohort A (76 men [67.9%]; median [range] age, 66.0 [46-90] years; 66 patients [58.9%] with programmed cell death ligand 1 [PD-L1] tumor proportion score ≥1%) and 102 patients received treatment in cohort B (62 men [60.8%]; median [range] age, 64.0 [35-81] years; 40 patients [39.2%] with PD-L1 tumor proportion score ≥1%). Objective response rate was 70.5% (79 of 112; 95% CI, 61.2%-78.8%) in cohort A and 70.6% (72 of 102; 95% CI, 60.7%-79.2%) in cohort B. Median duration of response was not reached, but 79.7% and 75.6%, respectively, had response duration of 12 months or longer. Grade 3 or higher pneumonitis occurred in 9 of 112 patients (8.0%) in cohort A and 7 of 102 (6.9%) in cohort B. Grade 3 to 5 treatment-related adverse events occurred in 72 of 112 (64.3%) and 51 of 102 (50.0%) patients, respectively.

CONCLUSIONS AND RELEVANCE

The findings of this phase 2, nonrandomized, 2-cohort study suggest promising antitumor activity of pembrolizumab plus cCRT and manageable safety in patients with previously untreated, locally advanced, stage III NSCLC.

KEYNOTE-799: Phase 2 trial of pembrolizumab plus platinum chemotherapy and radiotherapy for unresectable, locally advanced, stage 3 NSCLC

8512

Background: KEYNOTE-799 (NCT03631784) is an ongoing study of the anti‒PD-1 antibody pembrolizumab (pembro) plus concurrent chemoradiation therapy (cCRT) in patients (pts) with unresectable, locally advanced stage III NSCLC. Prior results from this study in a subset of pts (primary efficacy population) showed an ORR of 69.6% in cohort A (squamous and nonsquamous, n = 112) and 70.5% in cohort B (nonsquamous, n = 61), and grade ≥3 pneumonitis in 8.0% and 7.9% of pts, respectively. Here, we present results for all pts enrolled in KEYNOTE-799. Methods: This nonrandomized, multisite, open-label phase 2 trial enrolled pts aged ≥18 y with previously untreated, unresectable, pathologically confirmed, stage IIIA‒C NSCLC with measurable disease per RECIST v1.1. Pts in cohort A (squamous and nonsquamous) received 1 cycle of carboplatin AUC 6 and paclitaxel 200 mg/m2 and pembro 200 mg. After 3 wks, pts received carboplatin AUC 2 and paclitaxel 45 mg/m2 QW for 6 wks and 2 cycles of pembro 200 mg Q3W plus standard thoracic radiotherapy (TRT). Pts in cohort B (nonsquamous only) received 3 cycles of cisplatin 75 mg/m2, pemetrexed 500 mg/m2,and pembro 200 mg Q3W, and TRT in cycles 2 and 3. All pts received an additional 14 cycles of pembro 200 mg Q3W. Primary endpoints were ORR per RECIST v1.1 by blinded independent central review (BICR) and the incidence of grade ≥3 pneumonitis (per NCI CTCAE v4.0). Efficacy and safety were assessed in all pts as-treated. Results: Of 216 pts enrolled in KEYNOTE-799 (cohort A, n = 112; cohort B, n = 104), 112 in cohort A and 102 in cohort B received treatment. As of October 28, 2020, the median (range) time from first dose to database cutoff was 18.5 (13.6–23.8) mo in cohort A and 13.7 (2.9–23.5) mo in cohort B. ORR (95% CI) was 70.5% (61.2%‒78.8%) in cohort A and 70.6% (60.7%‒79.2%) in cohort B. Median DOR was not reached in either cohort (Table). ORR was similar regardless of PD-L1 status ([TPS <1% and TPS ≥1%]; Cohort A, 66.7% and 75.8%; Cohort B, 71.4% and 72.5%) and tumor histology (Cohort A, squamous, 71.2% and nonsquamous, 69.2%). Grade ≥3 pneumonitis occurred in 9 pts (8.0%) in cohort A and 7 (6.9%) in cohort B. Grade 3‒5 treatment-related AEs occurred in 72 pts (64.3%) in cohort A and 51 (50.0%) in cohort B. Conclusions: Pembro plus cCRT continues to demonstrate promising antitumor activity, regardless of PD-L1 TPS and tumor histology, and manageable safety in pts with previously untreated, locally advanced, stage III NSCLC with longer follow-up. Clinical trial information: NCT03631784. [Table: see text]

[Thoracic radiotherapy and control of respiration: current perspectives]

Three-dimensional conformal radiotherapy (3D CRT) is adversely affected by setup error and organ motion. In thoracic 3D CRT, breathing accounts for most of intra-fraction movements, thus impairing treatment quality. Breath control clearly exhibits dosimetric improvement compared to free breathing, leading to various techniques for gated treatments. We review benefits of different breath control methods--i.e. breath-holding or beam gating, with spirometric, isometric or X-ray respiration sensor--and argument the choice of expiration versus inspiration, with consideration to dosimetric concerns. All steps of 3D-CRT can be improved with breath control. Contouring of organs at risk (OAR) and target are easier and more accurate on breath controlled CT-scans. Inter- and intra-fraction target immobilisation allows smaller margins with better coverage. Lung outcome predictors (NTCP, Mean Dose, LV20, LV30) are improved with breath-control. In addition, inspiration breath control facilitates beam arrangement since it widens the distance between OAR and target, and leaves less lung normal tissue within the high dose region. Last, lung density, as of CT-scan, is more accurate, improving dosimetry. Our institution's choice is to use spirometry driven, patient controlled high-inspiration breath-hold; this technique gives excellent immobilization results, with high reproducibility, yet it is easy to implement and costs little extra treatment time. Breath control, whatever technique is employed, proves superior to free breathing treatment when using 3D-CRT. Breath control should then be used whenever possible, and is probably mandatory for IMRT.

Evaluation of deep inspiration breath-hold lung treatment plans with Monte Carlo dose calculation

PURPOSE

To evaluate dosimetry of deep inspiration breath-hold (DIBH) relative to free breathing (FB) for three-dimensional conformal radiation therapy of lung cancer with 6-MV photons and Monte Carlo (MC) dose calculations.

METHODS AND MATERIALS

Static three-dimensional conformal radiation therapy, 6-MV plans, based on DIBH and FB CT images for five non-small-cell lung cancer patients, were generated on a clinical treatment planning system with equivalent path length tissue inhomogeneity correction. Margins of gross to planning target volume were not reduced for DIBH plans. Cord and lung toxicity determined the maximum treatment dose for each plan. Dose distributions were recalculated for the same beams with an MC dose calculation algorithm and electron density distributions derived from the CT images.

RESULTS

MC calculations showed decreased target coverage relative to treatment-planning system predictions. Lateral disequilibrium caused more degradation of target coverage for DIBH than for FB (approximately 4% worse than expected for FB vs. 8% for DIBH). However, with DIBH higher treatment doses could be delivered without violating normal tissue constraints, resulting in higher total doses to gross target volume and to >99% of planning target volume.

CONCLUSIONS

If DIBH enables prescription dose increases exceeding 10%, MC calculations indicate that, despite lateral disequilibrium, higher doses will be delivered to medium-to-large, partly mediastinal gross target volumes, providing that 6-MV photons are used and margins are not reduced.