Citations

632 Background: Paltusotine is an oral, nonpeptide, selective somatostatin receptor 2 agonist. In a phase 2 study, treatment with once-daily paltusotine reduced the frequency and severity of carcinoid syndrome (CS) symptoms and was well tolerated. The effect of paltusotine on biomarkers of serotonin and 5-hydroxyindoleacetic acid (5-HIAA) was further explored. Methods: This exploratory study, without formal power calculations, included an 8-week randomized treatment phase (completed) and a 102-week open-label extension phase (currently ongoing). The purpose was to evaluate safety, pharmacokinetics, and exploratory efficacy endpoints, including changes in biomarkers of paltusotine treatment. Enrolled patients were adults with a stable, documented grade 1 or 2 neuroendocrine tumor (NET) and CS. These patients were actively symptomatic and either untreated with somatostatin receptor ligand (SRL) therapy (average of ≥4 bowel movements [BMs] per day or >2 flushing episodes per day in ≥2 days over a 2-week period) or washed out of SRL therapy (symptoms previously controlled on SRL), with demonstrated symptom worsening after washout. Patients were randomized to once-daily paltusotine 40 mg or 80 mg; one optional uptitration (from 40 mg to 80 mg or 80 mg to 120 mg) was permitted. Blood samples for assessment of biomarkers (serum serotonin and plasma 5-HIAA) were collected longitudinally from screening to end of treatment. Upper limit of normal was prespecified as 541 ng/mL for serotonin and 22 ng/mL for 5-HIAA. This analysis focuses on changes in biomarker from baseline to the end of 8-week randomized treatment phase and after approximately one year (48 weeks). Results: Thirty-six patients (n=9 untreated; n=27 SRL washout) were randomized. Mean age was 60.8 years (range 35-83), and 52.8% were female. Nineteen patients had grade 1 NETs, and 17 had grade 2 NETs. As reported previously, treatment with once-daily, oral paltusotine was well tolerated and reduced the frequency and severity of CS symptoms, justifying further clinical development of the 80 mg dose. Mean serum serotonin decreased from 1553.0 ng/mL at baseline to 643.9 ng/mL at Week 8, and mean plasma 5-HIAA decreased from 245.1 ng/mL to 159.7 ng/mL. There was a trend of untreated patients achieving a greater reduction in comparison to washout patients. At 48-week follow-up, mean serum serotonin was stabilized at 791.50 ng/mL (n=20), and mean plasma 5-HIAA was stabilized at 190.45 ng/mL (n=20). Conclusions: Paltusotine significantly reduced serotonin and 5-HIAA levels, with effects maintained at 48 weeks. Biomarker reductions paralleled reductions in BM and flushing frequency. These findings support further investigation in the ongoing phase 3 study (CAREFNDR, NCT07087054). Clinical trial information: NCT05361668 .

687 Background: The NAPOLI 3 study (NCT04083235, N = 770) reported that NALIRIFOX improved overall survival (OS) vs Gem+NabP with manageable toxicity in 1L treatment of metastatic pancreatic adenocarcinoma. We explored changes in CA19-9 levels and their potential associations with efficacy as an important tumor marker in pancreatic adenocarcinoma. Methods: In NAPOLI 3, CA19-9 was evaluated at baseline and every 8 weeks until patients discontinued study treatment. The detection limit of CA19-9 was 8000 kU/L in this study. The Cox proportional hazards regression and logistic regression were employed to investigate the relationship between CA19-9 decrease and OS, progression-free survival (PFS), and overall response rate (ORR). Results: Patients with evaluable CA19-9 (levels =< 8000) at baseline and additional measurements at weeks 8 and 16 were included in the analysis (NALIRIFOX, n = 179; Gem+NabP, n = 194). The median baseline CA19-9 level was 378.0 and 409.7 kU/L for the NALIRIFOX and Gem+NabP arms, respectively. Overall, patients with (vs without) any CA 19-9 decrease by week 16 had a higher ORR (59.9% vs 35.2%; p = 0.002), a longer median PFS (9.2 vs 6.2 months; p < 0.001) and a longer median OS (14.2 vs 8.7 months; p = 0.005), respectively in a pooled analysis of the treatments. In the NALIRIFOX arm, patients with any CA19-9 decrease by week 16 had a higher confirmed ORR of 65.1% compared with those without at 42.4% ( p < 0.001), a median PFS of 9.5 vs 7.1 months ( p < 0.001) and a median OS of 15.4 versus 8.4 months ( p = 0.004), respectively. In the Gem+NabP arm, patients with CA19-9 decrease by week 16 had a higher ORR of 55.5% compared with those without at 23.8% ( p = 0.012), a median PFS of 7.6 versus 5.8 months ( p < 0.001) and a median OS of 13.7 versus 11.9 months ( p = 0.235), respectively. Conclusions: CA19-9 decrease by week 16 has the potential to be an early prognostic factor for OS, PFS and ORR. The results should be interpreted with caution as a considerable percentage of patients were excluded due to non-evaluable CA19-9 that exceeded the lab detection limit of 8000 kU/L. Clinical trial information: NCT04083235 .

4006 Background: Liposomal irinotecan + 5-fluorouracil/leucovorin (5-FU/LV) is approved in the USA and Europe for mPDAC following progression with gemcitabine-based therapy. A phase 1/2 study (NCT02551991) demonstrated promising anti-tumor activity in patients with mPDAC who received first-line liposomal irinotecan 50 mg/m2 + 5-FU 2400 mg/m2 + LV 400 mg/m2 + oxaliplatin 60 mg/m2 (NALIRIFOX). Here, we present results from NAPOLI 3 (NCT04083235), a randomized, open-label, phase 3 study investigating the efficacy and safety of NALIRIFOX compared with nab-paclitaxel 125 mg/m2 + gemcitabine 1000 mg/m2 (Gem+NabP) as first-line therapy in patients with mPDAC. Methods: Eligible patients with histopathologically/cytologically confirmed untreated mPDAC were randomized (1:1; stratified by Eastern Cooperative Oncology Group [ECOG] performance status, geographic region and presence/absence of liver metastases) to receive NALIRIFOX on days 1 and 15 of a 28-day cycle or Gem+NabP on days 1, 8 and 15 of a 28-day cycle. The primary endpoint was overall survival (OS); secondary endpoints were progression-free survival (PFS), overall response rate (ORR) and safety. OS was evaluated when at least 543 events were observed using a stratified log-rank test with an overall one-sided significance level of 0.025. Results: Overall, 770 patients (NALIRIFOX, n = 383; Gem+NabP, n = 387) were included. Baseline characteristics were balanced between arms. At a median follow-up of 16.1 months, 544 events had occurred. Median OS was 11.1 months in the NALIRIFOX group versus 9.2 months in the Gem+NabP group; median PFS was 7.4 months versus 5.6 months. Median (95% CI) duration of response was 7.3 (5.8–7.6) and 5.0 (3.8–5.6) months in patients who received NALIRIFOX and Gem+NabP, respectively. Grade 3/4 treatment-emergent adverse events occurring in at least 10% of patients receiving NALIRIFOX versus Gem+NabP included diarrhea (20.3% vs 4.5%), nausea (11.9% vs 2.6%), hypokalemia (15.1% vs 4.0%), anemia (10.5% vs 17.4%) and neutropenia (14.1% vs 24.5%). Conclusions: First-line NALIRIFOX demonstrated clinically meaningful and statistically significant improvement in OS and PFS compared with Gem+NabP in patients with mPDAC. The NALIRIFOX safety profile was consistent with the profiles of the regimen components and generally manageable. Clinical trial information: NCT04083235 . [Table: see text]

LBA661 Background: Liposomal irinotecan administered with 5-fluorouracil/leucovorin (5-FU/LV) is approved in the USA and Europe for mPDAC following progression with gemcitabine-based therapy. A phase 1/2 study (Wainberg et al. Eur J Cancer 2021;151:14–24; NCT02551991) demonstrated promising anti-tumor activity in patients with mPDAC who received first-line liposomal irinotecan 50 mg/m2 + 5-FU 2400 mg/m2 + LV 400 mg/m2 + oxaliplatin 60 mg/m2 (NALIRIFOX). Herein, we present results from NAPOLI-3 (NCT04083235), a randomized, open-label, phase 3 study investigating the efficacy and safety of NALIRIFOX compared with nab-paclitaxel + gemcitabine as first-line therapy in patients with mPDAC. Methods: Eligible patients with histopathologically/cytologically confirmed untreated metastatic PDAC were randomized (1:1) to receive NALIRIFOX on days 1 and 15 of a 28-day cycle or nab-paclitaxel 125 mg/m2 + gemcitabine 1000 mg/m2 (Gem+NabP) on days 1, 8 and 15 of a 28-day cycle. Randomization was stratified by ECOG performance status, geographic region and presence or absence of liver metastases. The primary endpoint was overall survival (OS); secondary endpoints were progression-free survival (PFS), overall response rate (ORR) and safety. OS was evaluated when ≥ 543 events were observed using a stratified log-rank test with an overall 1-sided significance level of 0.025. Results: Overall, 770 patients (NALIRIFOX, n = 383; Gem+NabP, n = 387) were included. Baseline characteristics were well balanced between arms. At a median follow-up of 16.1 months, 544 events had occurred. The median OS was 11.1 months in the NALIFIROX arm as compared with 9.2 months in the Gem+NabP arm (HR 0.84 [95% CI 0.71–0.99]; p = 0.04); PFS was also significantly improved (7.4 months vs 5.6 months; HR 0.70 [0.59–0.84]; p = 0.0001). Grade 3/4 treatment-emergent adverse events (TEAEs) with ≥ 10% frequency in patients receiving NALIRIFOX versus Gem+NabP included diarrhea (20.3% vs 4.5%), nausea (11.9% vs 2.6%), hypokalemia (15.1% vs 4.0%), anemia (10.5% vs 17.4%) and neutropenia (14.1% vs 24.5%). Conclusions: First-line NALIRIFOX demonstrated clinically meaningful and statistically significant improvement in OS and PFS compared with Gem+NabP in treatment-naïve patients with mPDAC. The safety profile of NALIRIFOX was manageable and consistent with the profiles of the treatment components. Funding: Funded by Ipsen. Clinical trial information: NCT04083235 .[Table: see text]