Traynor, Anne M.

e21212 Background: Combining local ablative and systemic therapies in patients with oligometastatic NSCLC leads to improved overall survival (OS) and progression-free survival (PFS). The potential immunostimulatory effects of ablating all visible disease with SBRT in combination with dual immune checkpoint inhibition has prompted interest, but the toxicity and benefit are unknown. Methods: We conducted a phase Ib study to investigate the safety of SBRT, with doses between 30 and 50 Gy in five fractions to all sites of disease, followed by durvalumab 1500 mg IV in combination with tremelimumab 75 mg IV every 4 weeks x 4 cycles, followed by durvalumab maintenance until progression. Eligible patients had 1-6 extracranial metastatic sites, allowing multiple metastases per location, with all lesions suitable for SBRT, ECOG performance status 0-1, no actionable driver mutation, and no prior immunotherapy. The primary endpoint was safety of this combination. Secondary endpoints include PFS and OS. Dose-limiting toxicities (DLTs) (any Grade ≥ 3 toxicity) were evaluated from the first administration of SBRT until 28 days post start of durvalumab and tremelimumab. Baseline tumor mutational burden, PD-L1 expression on post-SBRT biopsy and circulating tumor cells will be correlated with outcomes. In this first cohort analysis, we assess the safety and outcomes of the first 17 patients. Results: From 2/2018-2/2021, the first 17 pts were enrolled. Characteristics of those enrolled included: median age 68 years, female/male 4/13, squamous/non-squamous 2/15, median number of non-central nervous system (CNS) metastatic sites 2 (1-5), median number of non-CNS metastatic lesions 2 (1-9), CNS involvement 6/17 (35.3%), previous treatment 4/17 (23.5%). DLTs were seen in 2/17 (11.8%) patients; DLTs were autoimmune hepatitis and autoimmune pancreatitis. Most treatment-related adverse events (TRAEs) were grade (G) 1/2. TRAEs included: all TRAEs n = 188, 88.2% (of patients); G 3 n = 17, 29.4%; G 4 n = 1, 5.8%. There were no treatment-related deaths. Five patients discontinued treatment due to grade 3/4 immune related adverse events (IRAE). At a median follow up of 20 months 11/17 (64.7%) patients are alive with 10/17 (58.8%) with no evidence of disease (NED). Six of 17 (35.2%) patients experienced disease progression and 4/17 (23.5%) patients died of disease progression. Median PFS and OS are not yet reached. Conclusions: There were no unexpected safety signals in the cohort of patients enrolled. The incidence of grade ≥ 3 IRAEs is similar to the treatment of advanced NSCLC and no additional toxicity was observed with the addition of SBRT. Clinical outcomes look promising with median OS and PFS not yet reached at 20 months median follow up. The study continues to enroll a second cohort and results will be updated. Clinical trial information: NCT03275597.

Introduction: Multikinase inhibitors have clinical activity in radioactive iodine refractory (RAIR) differentiated thyroid cancers (DTCs) but are not curative; optimal management and salvage therapies remain unclear. This study assessed clinical effects of pazopanib therapy in RAIR-DTC patients with progressive disease, examining in parallel biomarker that might forecast/precede therapeutic response. Methods: Assessment of responses and toxicities and of any association between thyroglobulin (Tg) changes cycle 1 and RECIST (response evaluation criteria in solid tumors) response to pazopanib therapy were prospectively undertaken in Tg antibody negative RAIR-DTC patients. RECIST progressive metastatic disease <6 months preceding enrollment was required. With a sample size of 68 (assuming 23 attaining partial response [PR]), there would be 90% chance of detecting a difference of >30% when the proportion of patients attaining PR whose Tg values decrease by >50% is >50% cycle 1 (one-sided α = 0.10, two sample test of proportions). Mean corpuscular volume (MCV) change or mutational status or pretreatment were also explored as early correlates of eventual RECIST response. Results: From 2009 to 2011, 60 individuals were treated and evaluated; (one additional patient withdrew; another was found ineligible before therapy initiation); 91.7% had previous systemic therapy beyond RAI. Adverse events included one death (thromboembolic) deemed possibly pazopanib associated. Twenty-two confirmed RECIST PRs resulted (36.7%, confidence interval; CI [24.6–50.1]); mean administered 4-week cycles was 10. Among 44 fully accessible patients, the Tg nadir was greater among the 20 attaining PR (median: −86.8%; interquartile range [IQR]: −90.7% to −70.9%) compared with the 28 who did not (median: −69.0%; IQR: −78.1% to −27.7%, Wilcoxon rank-sum test: p = 0.002). However, the difference in the proportion of PRs among those whose Tg fell ≥50% after cycle 1 versus those that did not were not significantly correlated (−23.5% [CI: −55.3 to 8.3]; Fisher's exact test p -value = 0.27). RECIST response was also not correlated with/predicted by early MCV change, receipt of prior therapy, or tumor mutational status. Conclusions: This trial prospectively confirmed pazopanib to have clinical activity and manageable toxicities in patients with progressive RAIR-DTC. Response to pazopanib, however, was not robustly forecast by early associated changes in Tg or MCV, by prior therapy, or by tumor mutational status. ClinicalTrials.gov NCT00625846.

5544 Background: Pazopanib, an orally bioavailable multitargeted inhibitor of kinases including VEGF-R, demonstrated impressive activity in metastatic differentiated thyroid cancer (49% durable RECIST PRs) and promising preclinical activity in anaplastic thyroid cancer (ATC) models, prompting its evaluation also as a candidate therapeutic in advanced ATC. Methods: A multicenter single arm phase II trial of 800 mg pazopanib daily was undertaken with the primary endpoint of RECIST response rate. The trial was designed such that there would be a 90% chance of detecting a response rate of >20% at the 0.10 significance level when the true tumor response rate is >5%. A pre-specified stopping rule designated that enrollment would cease unless 1 or more RECIST PRs+CRs were observed in the first 14 of 33 potential patients. Eligibility required informed consent, >18 years of age, performance status ECOG 0-2, systolic blood pressure (BP) <140 mm Hg and diastolic BP <90 mm Hg at entry, QTc interval <480 msecs, and measurable disease by RECIST criteria. Anatomical imaging and toxicity evaluations were required every 4 weeks. Results: Sixteen patients were enrolled. One patient withdrew prior to therapy, leaving 15 evaluable patients – 33.3% were male, with a median age of 66 years (range 45-77); 11 of 15 patients had progressed through prior systemic therapy. Four patients required 1-2 dose reductions, with the most common severe toxicities (CTC-AE version 3.0 grades 3-5) hypertension (13%) and pharyngolaryngeal pain (13%). Reasons for treatment discontinuation included: disease progression (12 pts), death on study due to a vascular event possibly related to treatment (1 pt.), and intolerability (radiation recall tracheitis – 1 pt, and uncontrolled hypertension – 1 pt). Although transient disease regression was observed in several patients, there were no confirmed RECIST tumor responses, triggering study closure at time of interim analysis. Two patients are alive with disease 9.9 months and 2.9 years post-registration; the remaining 13 died of disease. The median time to progression was 62 days and the median survival time was 111 days. Conclusions: Pazopanib has poor single agent activity in advanced anaplastic thyroid cancer.

265 Background: Gemcitabine (G) is the standard treatment for first- line PanC. PanC is one of the most hypoxic solid tumors. TH-302 is an inert prodrug of brominated isophosphoramide mustard and undergoes selective activation in deep hypoxia. As a single agent, tumor responses were reported in patients (pts) with metastatic melanoma, SCLC, and head/neck cancer at TH-302 weekly doses of 480-575 mg/m2. Methods: Eligible pts for the PanC expansion of this phase I/II study ( NCT00743379 ) had ECOG <1, locally advanced or metastatic PanC previously untreated with systemic chemotherapy other than adjuvant G, 5FU, and/or radiation. IV TH-302 was dosed at 240-575 mg/m2 (240 or 340 in expansion) with standard dose G (1000 mg/m2) on days 1, 8 and 15 of a 28-day cycle. Serum protein and microRNA hypoxia biomarkers were analyzed at baseline, start of cycle 3 and end of study. Results: 46 PanC subjects (12 locally advanced, 34 distant mets); median age: 63 (range 41-83); 24 male; ECOG 0/1 in 29/17 pts; RECIST response rate (RR) of 21%, median PFS of 6.1 mo (95%CI 4.8, 7.7) and median survival of 11.4 mo (95%CI 6.0, not reached) were observed. RR was 23% with median survival of 7.4 mo in pts with distant mets. 52% of pts had a >50% decrease in CA19-9. Common adverse events were skin or mucosal toxicity, nausea, fatigue and vomiting; most grade 1/2. Grade 3/4 neutropenia, thrombocytopenia and anemia in 68%, 64%, and 20% of pts respectively. The dose intensities at 240 mg/m2 and 340 mg/m2 were similar and related to hematologic toxicities. Skin toxicities were less common at 240 mg/m2. A TH-302 dose response was present with higher RR and PFS at 340 mg/m2. Initial serum hypoxia biomarkers did not identify a preferential pt population. Conclusions: The activity and clinical benefits of the combination of TH-302 with G in first line PanC are promising as compared to previous studies of G alone. TH-302 adds to the hematologic toxicity of G, but the regimen is well tolerated. The safety and activity provided rationale for comparing TH-302 plus G versus G alone in a randomized phase II trial ( NCT01144455 ) and indicate TH-302 may complement G by penetrating into the hypoxic regions of the PanC tumors where activation induces cytotoxicity. No significant financial relationships to disclose.

Abstract Lessons Learned Targeted therapy options for SCLC patients are limited; no agent, thus far, has resulted in a strategy promising enough to progress to phase III trials. Linsitinib, a potent insulin growth factor-1-receptor tyrosine kinase inhibitor, may be one agent with activity against SCLC. Despite lack of a reliable predictive biomarker in this disease, which may have partly contributed to the negative outcome reported here, linsitinib, although safe, showed no clinical activity in unselected, relapsed SCLC patients. Background. Treatment of relapsed small-cell lung cancer (SCLC) remains suboptimal. Insulin growth factor-1 receptor (IGF-1R) signaling plays a role in growth, survival, and chemoresistance in SCLC. Linsitinib is a potent IGF-1R tyrosine kinase inhibitor that potentially may be active against SCLC. Methods. In this phase II study, 8 eligible patients were randomly assigned in a 1:2 ratio to topotecan (1.5 mg/m2 intravenously or 2.3 mg/m2 orally, daily for 5 days for 4 cycles) or linsitinib (150 mg orally twice daily until progression). The primary endpoint was progression-free survival. Patients with relapsed SCLC, platinum sensitive or resistant, performance status (PS) 0–2, and adequate hematologic, renal, and hepatic function were enrolled. Patients with diabetes, cirrhosis, and those taking insulinotropic agents were excluded. Crossover to linsitinib was allowed at progression. Results. Fifteen patients received topotecan (8 resistant, 3 with PS 2) and 29 received linsitinib (16 resistant, 5 with PS 2). Two partial responses were observed with topotecan. Only 4 of 15 patients with topotecan and 1 of 29 with linsitinib achieved stable disease. Median progression-free survival was 3.0 (95% confidence interval [CI], 1.5–3.6) and 1.2 (95% CI, 1.1–1.4) months for topotecan and linsitinib, respectively (p = .0001). Median survival was 5.3 (95% CI, 2.2–7.6) and 3.4 (95% CI, 1.8–5.6) months for topotecan and linsitinib, respectively (p = .71). Grade 3/4 adverse events (&gt;5% incidence) included anemia, thrombocytopenia, neutropenia/leukopenia, diarrhea, fatigue, dehydration, and hypokalemia for topotecan; and thrombocytopenia, fatigue, and alanine aminotransferase/aspartate aminotransferase elevations for linsitinib. Conclusion. Linsitinib was safe but showed no clinical activity in unselected, relapsed SCLC patients.