Real-world outcomes in patients with first-line and second-line therapy for advanced esophageal squamous cell carcinoma

Background: Little is known about real-world outcomes for first-line and anti-PD-1 second-line treatment for advanced/metastatic esophageal squamous cell carcinoma (ESCC). Patients & methods: Retrospective data of advanced/metastatic ESCC patients treated between 2011 and 2021 were collected from Flatiron Health. Median duration of therapy (mDoT) and median overall survival (mOS) were evaluated for patients initiating first-line and anti-PD-1 second-line therapy. Results: Among patients receiving first-line therapy (n = 948), mDoT was 1.4 months and mOS was 16.0 months, with mOS of 16.0 and 18.0 months for the non-immunotherapy and immunotherapy cohorts, respectively. Among patients receiving anti-PD-1 second-line therapy (n = 60), mDoT was 5.7 months and mOS was 10.1 months. Conclusion: Patients with advanced/metastatic ESCC have short duration of therapy, and overall survival remains limited. This real-world study underscores the need for efficacious treatments for advanced/metastatic ESCC in the first- and second-line setting. Direct comparisons of emerging therapies in the real world are urgently needed.

Real-world treatment patterns and survival of U.S. patients receiving second-line anti-programmed cell death protein-1 therapy for advanced/metastatic esophageal squamous cell carcinoma

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Background: Current second-line (2L) therapies for patients (pts) with advanced/metastatic esophageal squamous cell carcinoma (adv/met ESCC), including docetaxel, paclitaxel and irinotecan, have demonstrated modest survival gains. The National Comprehensive Cancer Network added the use of anti-programmed cell death protein-1 (PD-1) therapies (e.g., pembrolizumab, nivolumab) in the 2L to their guidelines in 2020. A real-world evidence study of 2L therapy for adv/met ESCC patients reported a median (95% CI) overall survival (OS) of 201 (153-249) days but did not include recently approved anti-PD-1 agents. Other studies of 2L anti-PD-1 therapy relied on claims data without the ability to report survival. Limited studies exist for 2L ESCC real-world treatment patterns. Herein, we characterize the real-world treatment patterns and OS for a recent cohort of US pts initiating an anti-PD-1 2L therapy. Methods: Pts (≥ 18 years of age) from the United States diagnosed with adv/met ESCC and initiating an anti-PD-1 2L therapy between January 1, 2011 and February 28, 2021 were selected using the electronic health record (EHR)-derived de-identified Flatiron Health database. Pt characteristics and descriptive treatment patterns were reported. Duration of therapy (DoT; start of therapy until last administration) was computed and OS (start of therapy until death or last recorded medical activity) was estimated by the Kaplan Meier method. Results: 60 pts were included who initiated an anti-PD-1 2L therapy. At 2L initiation, the median age was 66 years, 65% were male, 53% were white, 82% had a history of smoking, and 53% had stage IV disease. The median DoT was 92 days and median OS was 303 days with variability across agents (Table) . Of the 60 pts, a total of 21 (35%) initiated 3L therapy (8 initiated an anti-PD-1; 13 initiated a non-anti-PD-1). Of the 39 (65%) pts who did not initiate a 3L therapy, 16 (41%) died within 60 days of the final 2L administration, 12 (31%) lacked 60 days of follow-up observation, and the remaining 11 (28%) patients had no further 2L treatment. Conclusions: Compared to prior real-world analyses, use of anti-PD-1 therapy in the 2L for patients with advanced/metastatic ESCC may be associated with survival gains over other approved non-anti-PD-1 therapies. However, future real-world studies are needed to directly compare PD-1 inhibitors with other 2L therapies.[Table: see text]

Abstract P1-18-18: Real-world natural history data among patients with PIK3CA-mutant and PIK3CA-wild-type advanced breast cancer

Background: Oncogenic mutations involving PIK3CA gene (PI3Kα) are observed in over 40% of patients with hormone receptor-positive (HR+) advanced breast cancer (ABC). Clinical efficacy of PI3K inhibition was demonstrated in a recent trial, but data on the natural history of disease by PIK3CA status are limited in ABC. We assessed patient and disease characteristics, treatment patterns, and clinical outcomes among patients with ABC treated at the Memorial Sloan Kettering Cancer Center in the United States, prior to the clinical availability of alpelisib (a PI3Kα inhibitor). Methods: A retrospective medical record review of adult patients diagnosed with HR+ and human epidermal growth factor receptor 2-negative (HER2-) ABC between January 2014 and December 2018 was conducted. Data collection is ongoing and updated results will be presented. Cohorts were determined by eligible patients’ PIK3CA gene status (i.e., mutant or wild-type [WT]), and were frequency matched to have an equal distribution of the year of ABC diagnosis between cohorts. Study measures were descriptively summarized, and the Kaplan-Meier method was used to estimate progression-free survival (PFS) and left truncation-adjusted overall survival (OS), in months. To assess the association of PIK3CA mutation status on OS, a multivariate Cox proportional hazard model adjusted for age, race, stage at diagnosis, menopausal status, visceral disease, bone only disease, and Charlson Comorbidity Index score was computed. Additional adjustment on treatment modalities is planned. Results: Data for 249 PIK3CA-mutant and 143 PIK3CA-WT patients was analyzed. For the mutant cohort, the mean (SD) age was 59.0 (11.2) years, 80.7% were White, 30.9% were diagnosed with de novo ABC, and 54.6% were postmenopausal at initial BC diagnosis. Visceral- and bone only-disease were observed among 41.4% and 21.7% of patients, respectively. Among patients with a single PIK3CA mutation (n=220, 88.4%), the most common mutations were H1047R (37.3%), E545K (20.5%), and E542K (12.7%). Multiple PIK3CA mutations were observed in 29 (11.6%) patients. For the WT cohort, the mean (SD) age was 56.3 (12.1) years, 77.6% were White, 39.9% were diagnosed with de novo ABC, and 45.5% were postmenopausal at initial BC diagnosis. Visceral- and bone-only disease were observed among 51.8% and 16.8% of patients, respectively. Most common 1st-line treatments for ABC were cyclin-dependent kinase 4 and 6 inhibitor (CDK4/6i) + aromatase inhibitor (AI) (mutant: 38.6%; WT: 40.6%), AI only (mutant: 21.3%; WT:22.4%), CDK4/6i + fulvestrant (mutant: 15.7%; WT: 7.7%), and chemotherapy-based regimens (mutant: 9.6%; WT: 11.2%). Chemotherapy-based regimens were the most common 2nd- (mutant: 25.6%; WT: 21.3%) and 3rd-line (mutant: 41.4%; WT: 33.9%) therapies for both cohorts. Results for PFS and OS are presented in Table 1, and the survival risk was similar for both cohorts (adjusted HR: 1.18, 95% CI: 0.88-1.60). Conclusion: In this preliminary analysis of HR+/HER2- ABC, CDK4/6i-based regimens were the most common 1st-line therapy, and PFS to 1st-3rd line therapies and OS were not statistically significantly different. The recent availability of PI3K inhibitor therapy may improve clinical outcomes among patients with PIK3CA-mutant tumors.

Table 1.Progression-free Survival and Overall Survival Among Patients with HR+/HER2- ABC.PIK3CA MutantPIK3CA Wild-typeProgression-free Survival (months)1st line – all patients (n)249143Median (95% CI)12.4 (10.4-15.2)13.5 (10.3-16.0)1st line – CDK4/6i + AI (n)9658Median (95% CI)21.0 (17.0-27.9)19.1 (9.4-28.6)2nd line – all patients (n)211127Median (95% CI)7.3 (6.3-10.4)6.8 (5.4-8.8)2nd line – chemotherapy-based regimens (n)5427Median (95% CI)5.1 (3.7-6.3)5.2 (3.3-6.3)3rd line – all patients (n)186115Median (95% CI)4.5 (3.7-5.4)5.7 (4.7-8.9)3rd line – chemotherapy-based regimens (n)7739Median (95% CI)4.3 (3.0-5.1)4.7 (3.0-7.7)Overall Survival (months)Median (95% CI)47.4 (42.8-52.4)55.5 (44.9-61.9)

Citation Format: Pedram Razavi, Rohan C Parikh, Barbara Acevedo, Abigail Hitchens, Mehnaj Ahmed, Anton Safonov, Emanuela Ferraro, Komal Jhaveri, Michelle Sidel, Stacey Simmons, Mark Robson, Sarat Chandarlapaty, Sanjeev Balu. Real-world natural history data among patients with PIK3CA-mutant and PIK3CA-wild-type advanced breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-18-18.

Prevalence and characterization of dermatologic adverse events related to alpelisib (BYL719) in breast cancer patients

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Background: Rash develops in approximately 50% of breast cancer patients receiving alpelisib, often requiring dose modifications. Herein, we describe the characteristics of alpelisib-related dermatologic adverse events (dAEs). Methods: A single center retrospective analysis was conducted via review of electronic medical records. We collected clinical, laboratory and management data relevant to patients treated with alpelisib for advanced breast cancer under four different randomized clinical trials or post approval by regulatory agencies from 6/1/2013 to 7/31/2019. Type and severity of dAEs was recorded using the Common Terminology Criteria for Adverse Events version 5.0 (CTCAE v5.0). Results: A total of 102 patients (mean age 56 years, range 27-83) receiving alpelisib from 200 to 350 mg daily, most frequently in combination with endocrine therapy (79, 77.5%) were included. We identified 41 (40.2%) patients with all-grade rash [CTCAE grade 1/2 = 22 (21.6%); CTCAE grade 3 = 19, (18.6%)] distributed primarily along the trunk (18, 78%) and developing, on average, within 12.8 +/- 1.5 days of treatment initiation (n = 38). Mean duration of rash was 7.1 +/- 3.8 days; and no grade 4 dAEs were observed. Of 29 patients with documented morphology of alpelisib-related dAEs, the majority (26, 89.7%) had maculopapular rash. Thirteen (68%) of 19 patients with any-grade rash and report of any associated symptoms had pruritus (7, 36%) or burning pain (6, 32%). All-grade dAEs correlated with an increase in serum eosinophils from 2.7% to 4.4% (p < 0.05), and prophylaxis with non-sedating antihistamines (n = 43) was correlated with a reduction of grade 1/2 rash onset (OR 0.39, p = 0.09). Sixteen (84.2%) of 19 patients with grade 3 dAEs had interruption of alpelisib, followed by management with antihistamines, topical and/or systemic corticosteroids. We did not observe rash recurrence in 12 (75%) of these 16 patients who re-initiated therapy; and the majority (9, 56.3%) were re-challenged without a dose reduction. Conclusions: Pruritus and increased blood eosinophils occur with maculopapular rash within the first two weeks of initiating alpelisib and persists for approximately seven days. To reduce onset of grade 1/2 rash, non-sedating antihistamines (i.e. cetirizine) are recommended during the first eight weeks. While grade 3 rash leads to interruption of alpelisib, dermatologic improvement is evident with systemic corticosteroids; and most patients can resume therapy at a maintained or reduced dose upon re-challenge.