Molina, Julian R.

e20554 Background: The paradigm for locally advanced non-small cell lung cancer has been markedly altered to include maintenance durvalumab (D) post completion of definitive chemoradiation (CRT) following the publication of the Pacific trial in 2018. The toxicity of this treatment has not been well evaluated in the real-world setting. Methods: We identified 42 patients (pts) with Stage IIB-IIIC NSCLC treated at Mayo Clinic Rochester between 6/1/2018 and 10/1/2020 who received definitive CRT followed by maintenance D. Data were abstracted by retrospective chart review under an IRB approved protocol. Results: Median age was 66 yrs (range 47-90) and 62% were women. Primary lung cancer histology included 19 adenocarcinoma, 20 squamous cell, and 3 adenosquamous. The distribution of stages was: IIB (4/42), IIIA (15/42), IIIB (19/42), IIIC (4/42). Approximately half of patients had PDL1 expression > 25% (20/42). With a median follow up of 12.2 months (calculated from first cycle of D; range 4.2-30.5 months), 14 had completed one year of maintenance D, 16 were receiving ongoing D, and 10 stopped D early with 6/12 discontinuing due to disease progression (4/6 local progression, 2/6 distant progression). Other reasons for discontinuation (5/10) included grade 3 colitis, grade 2 hepatitis, aspergillus lung infection, and flare of autoimmune disorders. One quarter of patients experienced grade 2 radiation pneumonitis (RP; 10/42) with median time to development of RP 78 days from end of CRT and 45 days from start of D. RP was determined by multidisciplinary review of imaging and treatment fields. 17/42 patients developed immune related adverse events (see Table for details). There was minimal overlap between the patients who experienced pneumonitis and immune related toxicity; 2/17 had both pneumonitis and immune related toxicity (hepatitis, thyroiditis). Conclusions: In our early experience with the Pacific regimen, 29% of patients did not complete D due to either toxicity or progression during D administration. Pneumonitis was common (10/42 patients) although there were no grade 3 events. Nearly half of the patients developed an immune-related adverse event. Further analysis is needed to evaluate the real-world toxicity of this treatment as well as oncologic outcomes.[Table: see text]

9093 Background: Treatment addressing non-small cell lung cancer (NSCLC) harboring EGFR or HER2 exon 20 insertion mutations remains an unmet need. These tumors are associated with a high incidence of CNS metastases and unfavorable survival rates. Poziotinib is a potent, irreversible, tyrosine kinase inhibitor (TKI) with a structure that can overcome the steric hindrance of the exon 20 limited binding pocket. Preclinical data suggest poziotinib CNS penetration, and here we show meaningful poziotinib CNS activity in patients with NSCLC harboring exon 20 insertion mutations in an ongoing multi-cohort, multi-center Phase 2 study (ZENITH20; NCT03318939). Methods: ZENITH20 enrolled previously treated and naïve patients with advanced/metastatic NSCLC and EGFR or HER2 exon 20 insertion mutations in several cohorts: Cohort 1 (C1) EGFR previously treated; Cohort 2 (C2) HER2 previously treated and Cohort 3 (C3) EGFR treatment-naïve. All patients with stable CNS metastases at baseline were included. Poziotinib (16 mg) was administered orally QD, with follow-up for up to 24 months. The primary endpoint was Objective Response Rate (ORR) evaluated centrally using RECIST v1.1 by an independent image review committee. Secondary endpoints included Disease Control Rate (DCR), Duration of Response (DOR), Progression-Free Survival (PFS) and safety. Primary efficacy results have been previously released. Intracranial response was determined based on the modified RECIST criteria. Results: A total of 284 patients across 3 cohorts (C1 n=115; and C2 n=90; and C3 n=79) with a median age of 60.5 years were enrolled. The median follow-up was 7.3, 8.3, and 9.2 months for all patients in C1, C2, and C3, respectively. In NSCLC patients that had baseline CNS lesions (N=36), the analysis showed a patient-based ORR of 22.2% (8/36) and a DCR of 88.9% (32/36). One patient in each cohort had a complete intracranial response and stable disease was 80.6% across 3 cohorts and 92.9% in C2. Two patients each in C1 and C3 had progressive disease (PD) and none had CNS progression in C2 (Table). Conclusions: Poziotinib exhibited clinically meaningful CNS activity in patients with EGFR or HER2 exon 20 mutations in ZENITH20 Cohorts 1-3. The majority of the patients had no CNS progression and 3/36 patients had intracranial complete responses. The preliminary data suggest that poziotinib may provide a meaningful treatment alternative for patients with NSCLC that harbor EGFR or HER2 exon 20 mutations and who present with CNS metastases that have poor prognosis. Clinical trial information: NCT03318939. [Table: see text]

Abstract Objectives To evaluate SATB2 expression and prognostic implications in a large cohort of thoracic neuroendocrine tumors. Methods Surgical pathology files (1995-2017) and an institutional thymic epithelial tumor database (2010-2020) were searched for resected neuroendocrine tumors. Cases were stained with SATB2 (clone EP281). Percent SATB2-positive tumor cells and expression intensity were scored. Results In the lung, SATB2 was expressed in 5% or more of tumor cells in 29 (74.4%) of 39 small cell carcinomas and 9 (22.5%) of 40 atypical and 26 (40.6%) of 64 typical carcinoid tumors. SATB2 percent tumor cell expression and intensity were higher in small cell carcinomas than in carcinoid tumors (both P < .001, respectively). After adjusting for tumor subtype, SATB2 expression did not correlate with outcome. In the thymus, four (100%) of four atypical carcinoid tumors and one large cell neuroendocrine carcinoma but no small cell carcinoma (n = 2) expressed SATB2 in 5% or more of tumor cells. Conclusions SATB2 (clone EP281) is expressed in a large subset of pulmonary and thymic neuroendocrine tumors and therefore does not appear to be a useful marker to identify the origin of neuroendocrine tumors. Validation studies are needed, specifically including thymic neuroendocrine tumors, as the expression pattern might be different in those tumors.

Introduction: The impact of beta blocker use on surgical outcomes of cancer patients receiving immunotherapy is unknown. Hypothesis: Beta blocker use is associated with lower post-operative mortality in cancer patients on immunotherapy. Methods: We used an institutional Advanced Cohort Explorer to identify all patients who underwent any surgical procedure less than 90 days after receiving immunotherapy. Data on the procedure performed as well as the post-operative outcome were collected and analyzed per the pre-operative beta blocker use status. Results: A total of 233 patients underwent surgery between 09/2011-06/2019. Mean age was 64.7 years (range: 16-92). The most common cancer diagnoses were lung (48, 44.4%), melanoma (49, 45.4%) and kidney (11, 10.2%). Immunotherapy medications were pembrolizumab ( 127, 54.5%), nivolumab (51, 21.9%), ipilimumab (43, 18.5%), atezolizumab (11, 4.7%) and avelumab (1, 0.43%). Pre-operative beta blocker use was documented in 140 (60.1%) patients. Most common surgical procedures were skin resection (75, 32.1%), wound repair (47, 20.2%), vascular procedures (36, 15.5%), urethral procedures 16 (6.9%) and sentinel lymph node biopsies (10, 4.3%). The 30-day mortality rate was 10.3% (24 deaths). In a multi-variable logistic regression analysis, pre-operative use of beta blockers was associated with a lower risk of death within 30 days from surgery (OR 0.34, CI 0.13-0.87, P=0.024). 30-day mortality rates were higher in patients undergoing vascular (50%, 17 of 34) versus non-vascular (3.5%, 7 of 199) procedures (P<0.0001) in a Chi Square test. Conclusions: Beta blocker use is associated with a lower 30-day mortality rate after surgical procedures in cancer patients treated with immunotherapy. Further investigation is warranted.

Abstract Chromosome region maintenance protein 1 (CRM1) mediates protein export from the nucleus and is a new target for anticancer therapeutics. Broader application of KPT-330 (selinexor), a first-in-class CRM1 inhibitor recently approved for relapsed multiple myeloma and diffuse large B-cell lymphoma, have been limited by substantial toxicity. We discovered that salicylates markedly enhance the antitumor activity of CRM1 inhibitors by extending the mechanisms of action beyond CRM1 inhibition. Using salicylates in combination enables targeting of a range of blood cancers with a much lower dose of selinexor, thereby potentially mitigating prohibitive clinical adverse effects. Choline salicylate (CS) with low-dose KPT-330 (K+CS) had potent, broad activity across high-risk hematological malignancies and solid-organ cancers ex vivo and in vivo. The K+CS combination was not toxic to nonmalignant cells as compared with malignant cells and was safe without inducing toxicity to normal organs in mice. Mechanistically, compared with KPT-330 alone, K+CS suppresses the expression of CRM1, Rad51, and thymidylate synthase proteins, leading to more efficient inhibition of CRM1-mediated nuclear export, impairment of DNA-damage repair, reduced pyrimidine synthesis, cell-cycle arrest in S-phase, and cell apoptosis. Moreover, the addition of poly (ADP-ribose) polymerase inhibitors further potentiates the K+CS antitumor effect. K+CS represents a new class of therapy for multiple types of blood cancers and will stimulate future investigations to exploit DNA-damage repair and nucleocytoplasmic transport for cancer therapy in general.

8106 Background: Bcl-2 family proteins are expressed in SCLC and are associated with chemotherapy resistance. AT-101 is an oral, pan Bcl-2 family protein inhibitor (Bcl-2, Bcl-XL, Mcl-1, and Bcl-w) and potent inducer of proapoptotic proteins. AT-101 has demonstrated activity in SCLC models, including those that express Mcl-1 and are resistant to other Bcl-2 inhibitors. The P1 portion of the study was previously reported. Methods: Pts ≥18 years of age, PS 0–1, with relapsed or refractory SCLC after first line chemotherapy with measurable disease per RECIST were eligible. Pts were stratified into 2 cohorts; cohort A ≥ 60 days and cohort B < 60 days relapse from prior chemotherapy and treated with T 1.25 mg/m2 daily and AT-101 40 mgs daily on days 1–5, q21 along with the use of myeloid growth factors. Adverse Events (AEs) were graded by the NCI CTCAE v. 3.0. Efficacy assessments (RECIST) were performed every 6-weeks. A 2-stage design was used with power/alpha of 80%/0.05 to detect a RR of > 25% and > 5%, in cohort A and B respectively. Results: 36 pts enrolled: ages 41–76; cohort A/B 23/13. The PR/SD/PD/NE rates were 17%/70%/9%/4% and 8%/54%/23%/15%, in cohorts A/B respectively. The median times to progression (TTP) were 18 and 13 weeks, respectively. The most common (>20 %) AEs (all grades): anemia (64%); neutropenia (53%); nausea (47%); fatigue (44%); thrombocytopenia (42%); dyspnoea (25%); and vomiting (22%). Most common Grade 3/4 related events (>5%): neutropenia (31%); thrombocytopenia (25%); anemia (14%); and asthenia (6%). No ileus was reported. Conclusions: AT-101 can be safely combined with T. The observed toxicities were consistent with the known rates of G4 cytopenias of T alone. The response rates observed did not meet the criteria for additional enrolment; however, many patients had a best response of SD and the median TTP in both cohorts was favorable compared to historical controls. Additional trials of AT-101 in SCLC are ongoing. [Table: see text]

8085 Background: Historically, tumor response has been the primary endpoint in phase II (P2) trials in ED-SCLC. We investigated the suitability of alternate PFS based endpoints to predict OS as early evidence of efficacy in the P2 setting. Methods: Individual patient (pt) data from 942 pts from 11 previously untreated ED-SCLC P2 and phase III (P3) platinum- or paclitaxel-based treatment trials were pooled. Best response (BR), response confirmed (RC), objective status at 16 weeks (RR16), and PFS rate at 5 and 6 months were considered. Percent agreement (PA) and kappa (k) for PFS5, PFS6, BR, RC, and RR16 with OS at 12 months (OS12) was calculated on a per-pt basis and predictive utility was assessed using the area under the receiver operating characteristic (A- ROC) curve in logistic models. Cox models were used to assess the prognostic impact of the endpoints on subsequent survival, using landmark analysis. Results: The median OS and PFS were 9.6 m and 5.5 m, respectively. PFS5 and PFS6 had the highest PA, k, and A-ROC values, and were predictive of subsequent survival in the landmark analysis (p <0.0001; c-statistics ≥ 0.60). While RR16 and BR were significantly associated with subsequent survival (p<0.0001, c-statistics of 0.61 and 0.57, respectively) the PA, k, and A-ROC values were lower. Conclusions: PFS rate at 5 and 6 months is more predictive of 12-month OS and subsequent survival than tumor response in untreated ED-SCLC. PFS based endpoints should be routinely used as primary endpoints in P2 trials within ED-SCLC. [Table: see text] No significant financial relationships to disclose.

7544 Background: NCCTG N0028 was a trial that determined the MTD of RT that could be given with carboplatin & paclitaxel was 74 Gy/34 fractions. This secondary analysis was performed to determine the survival of pts treated on this trial. Methods: Eligible pts had medically or surgically unresectable NSCLC, PS=0–1, weight loss <10% in the prior 3 months(mo), no prior therapy, adequate laboratory & pulmonary functions. Included were 25 pts with clinical stages I (4pts), II (1 pt), IIIa (12 pts), & IIIb (8 pts). Treatment included: weekly I.V. paclitaxel (50mg/m2) & carboplatin (AUC=2) during RT. The RT included 2 Gy daily to an initial dose of 70 Gy. The total dose was increased in 4 Gy increments until the MTD was determined. RT was delivered with 3-D treatment planning but no elective nodal RT. Three pts received 70 Gy, 18 pts received 74 Gy, & 4 pts received 78Gy. Results: Pts were followed until death or from 10–67 mo (median: 28mo) in those alive at last evaluation. The median survival (MS) of the entire cohort was 42mo. The 5 stages I-II pts had a MS of 53 mo & the 20 stage III pts had MS of 42mo. Conclusions: Standard dose RT is unable to sterilize disease in the majority of pts with unresectable NSCLC. While the addition of chemotherapy has significantly improved survival of these pts, the MS is generally 15–24 mo. These preliminary results suggest higher than standard doses of RT may improve disease control & prolong survival. A phase III trial comparing standard-dose RT(60Gy) to high-dose RT (74Gy) is open and should more definitively address the issue of RT dose with concurrent chemotherapy for unresectable NSCLC. Future technological improvements in imaging & targeting will provide methods to safely administer even greater RT doses which will likely further improve disease control. No significant financial relationships to disclose.

3521 Background: Systemic therapies have had little impact on the outcomes of patients with advanced differentiated thyroid cancers. Methods: A three-outcome one-stage Phase II trial was conducted to assess the anti-tumor activity and toxicities of the orally bioavailable VEGF/tyrosine kinase inhibitor pazopanib (800 mg daily) in patients with advanced and progressive radioiodine-insensitive differentiated thyroid cancers. Up to 2 prior therapies were allowed, with measurable disease required. Design: at the 0.10 significance level, there would be a 90% chance of detecting a RECIST response rate of >20% given a true response rate of >5%; with the regimen considered promising if >4 confirmed responses observed. Results: From February to November 2008, 32 patients (53% male) aged 23–79 years (median: 63 years) were enrolled. Common sites of metastases were: lung (100%), nodes (52%), and bone (39%). Measurement data are available for 26 patients, with the median number of cycles administered thus far 4 (range: 1–8, total: 101). Overall, therapy has been well tolerated. Six patients (23%) required dose reduction due to: grade 2+ ALT (3 pts), grade 3 mucositis (1 pt); grade 3 diarrhea and dehydration (1 pt), and grade 3 abdominal pain (1 pt.). Other serious toxicities included grade 3 colon perforation and grade 3 chest pain (1 pt). No thyroglobulin antibody (TGA) negative patient has become TGA positive, and 11 of 16 patients (69%) with initially elevated thyroglobulin levels experienced a decline in thyroglobulin of >50%. Five RECIST partial responses have been confirmed to date (19%). Two patients are alive with disease progression and another has died from disease progression. Conclusions: Pazopanib appears to have both a favorable toxicity profile and promising clinical activity in patients with advanced and progressive differentiated thyroid cancers. Supported in part by NCI CA15083 and CM62205. No significant financial relationships to disclose.