Baran, Andrea

12047 Background: Metastatic colorectal cancer (mCRC) is a leading cause of death, particularly in older adults. Regorafenib (REGO) is an FDA-approved oral multi-kinase inhibitor for refractory mCRC based on the CORRECT trial results, but older adults were underrepresented with a median age of 61 (54–67). This study aimed to evaluate REGO safety in older adults with mCRC and assess the feasibility of using geriatric assessment (GA) to predict toxicity risk. Methods: 27 subjects (PTs) enrolled (median age 73, range 65-85) and started at 120mg of REGO for 21 days of a 28-day cycle with provider discretion to escalate to full dose of 160mg after cycle 1. GA was conducted at enrollment, 4 weeks later, and then every 3 months to monitor for any deterioration. GA assessed 8 geriatric domains (comorbidity, functional status, physical performance, cognition, psychological state, nutrition, medication review, and social support) using validated tools. Primary objective was to assess grade 3-5 toxicity rate, with secondary objectives evaluating REGO efficacy and exploring baseline GA and toxicity risk associations. Kaplan-Meier method was used to estimate median overall survival (OS) and progression-free survival (PFS) from date of consent. Continuous GA measures were compared using non-parametric Wilcoxon rank-sum test, and binary GA measures were compared using Fisher’s exact test. Results: Of 27 PTs enrolled, 15 were male, 12 were female, and 19 identified as white. At baseline, 77.7% of PTs had at least 3 (1-9) GA impairments. Physical performance (80.8%), comorbidity (75%), and cognition (69.2%) were the most prevalent impaired GA domains. 40% required dose reduction by end of cycle 2, and none escalated to full dose. 55% of PTs completed cycle 3. Main reasons for drug discontinuation were disease progression (80%) and toxicity (12%). 74.1% of PTs experienced at least one treatment-related grade 3-4 toxicity. Fatigue (33%), hypertension (30%), and hand-foot syndrome (15%) were the leading grade 3-4 toxicities. Median OS was 5.6 months (95% CI: 3.6-12.2m), and median PFS was 2.8 months (95% CI: 2.5-3.4m). There was no significant difference in baseline GA measures between those who experienced toxicities and those who did not. No statistically significant toxicity risk was associated with any baseline GA impairment. The prevalence of impaired mini-nutritional assessment increased over 4 weeks (58% to 91%, p < 0.01), and median Short Physical Performance Battery (SPPB) scores decreased (7 to 6, p = 0.03). Conclusions: The study found that older adults with mCRC had comparable survival with REGO but experienced high toxicity. This may be ameliorated by recently published step-wise REDOS dosing method and should be considered in older adults with mCRC. The study confirms the feasibility of implementing GA within clinical trials. More data is needed on the role of GA in predicting toxicity with targeted therapies. Clinical trial information: NCT02466009 .

Abstract Background Age has long been recognized as a poor prognostic factor in diffuse large B-cell lymphoma (DLBCL) and more recently, a lower baseline quality of life (QOL) in patients with aggressive lymphomas has been associated with an inferior overall survival (OS) (Thompson et al, 2018). Older patients with DLBCL are a heterogeneous population and commonly have comorbid conditions. A concerted effort to identify prognostic factors specific to this population is needed, including QOL. Event free survival at 24 months (EFS24) is a well validated endpoint in DLBCL (Maurer et al, 2014) and is clinically relevant in older patients. We hypothesized that baseline clinical factors and QOL would be associated with EFS24 this patient group. Methods Newly diagnosed lymphoma patients were prospectively enrolled within 9 months of diagnosis into the University of Iowa/Mayo Clinic Lymphoma SPORE Molecular Epidemiology Resource (MER). Patients ≥70 years of age with DLBCL were utilized in this study. All pathology was reviewed by a lymphoma hematopathologist. Clinical variables were abstracted from the medical record. QOL was assessed at enrollment using a single item Linear Analogue Self-Assessment (LASA) and the 27-item Functional Assessment of Cancer Treatment-General questionnaire (FACT-G), which includes physical, social, emotional, and functional well-being domains. QOL scores were converted to a 0-100 scale to facilitate modeling. QOL was analyzed in patients who completed 80% of the FACT-G questions. Characteristics of the study population were compared using the Wilcoxon rank sum test. Odds ratios (ORs) and 95% confidence intervals (CI) were used to estimate the associations of clinical and continuous QOL variables with failure to achieve EFS24 using logistic regression models, with a stepwise approach to identify parsimonious multivariate models. Results A total of 389 patients ≥70 years were identified with DLBCL in the MER from 2002-2015; patient characteristics are described in the Table. In the entire study population, univariate predictors of EFS24 failure included age (OR per 10 years=1.85, 95% CI: 1.26-2.71), ECOG PS ≥2 (OR=4.78, 95% CI: 2.92-7.83), elevated LDH (OR=3.59, 95% CI: 2.27-5.65), stage III-IV (OR=1.94, 1.25-3.02), bulky disease (OR=2.86, 95% CI: 1.43-5.72), international prognostic index (OR=8.71 for IPI 5 vs IPI 0, 95% CI: 3.04-24.9), and receipt of an anthracycline (OR=0.25, 95% CI: 0.12-0.51), while none of the other variables in the Table, including the QOL variables, were statistically significant. In a stepwise multivariate analysis, only ECOG PS ≥2 (OR= 3.56, 95% CI: 2.09-6.06) and elevated LDH (OR=2.86, 95% CI: 1.78-4.60) remained significant predictors of EFS24 failure. QOL data were available on 220 patients, with 120 completing QOL questionnaires prior to receipt of chemotherapy. Compared to participants who completed their FACT-G before the initiation of chemotherapy, the median FACT-G physical (85.7 v. 71.4, p=0.005) and functional (71.4 vs 57.1, p=0.008) scores were lower in participants completing FACT-G after initiation of therapy, were higher on FACT-G emotional (79.2 vs 83.3, p=0.03), and showed no differences on FACT-G social (89.3 vs 91.7, p=0.60) or FACT-G total score (78.2 vs 74.1, p=0.17). Given these differences, we restricted the QOL analysis to those with pre-treatment data. In univariate analysis, the LASA score (OR= 0.98, 95% CI: 0.84-1.14), the FACT-G total (OR=0.99, 95% CI: 0.96-1.01), physical (OR=0.98, 95% CI: 0.97-1.00), social (OR=1.00, 95% CI: 0.98-1.03), emotional (OR= 1.00, 95% CI: 0.98-1.02), and functional (OR=0.99, 95% CI: 0.98-1.01) scores were not associated with EFS24 failure. In a stepwise multivariate analysis of clinical variables in patients with pretreatment QOL scores, only ECOG PS ≥2 (OR=3.56, 95% CI: 1.30-9.72) and female sex (OR=0.37, 95% CI: 0.16-0.85) were associated with failure to achieve EFS24. Conclusions In patients aged 70 years and older, ECOG PS and LDH were the strongest independent predictors of failure to achieve EFS24. As expected, physical and functional scores were lower in patients who completed their QOL after initiation of treatment. Restricting the analysis to patients with pre-treatment data, QOL was not associated with failure to achieve EFS24. Additional studies are needed to identify the most robust clinical predictors of EFS24, while QOL does not appear to be an important predictor of EFS24. Disclosures Reagan: Seattle Genetics: Research Funding. Maurer:Morphosys: Research Funding; Celgene: Research Funding; Nanostring: Research Funding. Cerhan:Celgene: Research Funding; Nanostring: Research Funding; Jannsen: Other: Scientific Advisory Board.

Summary Unconjugated monoclonal antibodies (mAbs) are an important component of effective combination therapies for chronic lymphocytic leukaemia (CLL). Antibody-dependent phagocytosis (ADP) is a major mediator of mAb cytotoxicity, but there is limited knowledge of the determinants of ADP efficacy. We used macrophages derived in vitro from autologous circulating monocytes to test the effects of mAb structure and concentration, target : effector cell ratio, duration of co-incubation and CLL cell CD20 expression on ADP. Next-generation anti-CD20 mAbs (ofatumumab, ublituximab, obinutuzumab, ocaratuzumab) were significantly more effective at inducing ADP compared to rituximab, but none were as effective as the anti-CD52 mAb alemtuzumab. Ofatumumab (10 μg/ml) used as a representative next-generation anti-CD20 mAb achieved an ADP plateau at 3 h co-incubation with a target : effector ratio of 10 : 1 (mean = 2·1 CLL cells/macrophage, range = 1·5–3·5). At 0·156 μg/ml (the lowest concentration tested) ofatumumab ADP was significantly higher than alemtuzumab. However, ofatumumab-induced ADP did not increase significantly at higher mAb concentrations. We show that anti-CD20 mAb ADP efficacy is determined by the mAb characteristics, target : effector ratio and incubation time. We suggest that preclinical evaluation of anti-CD20 mAbs to understand the determinants of ADP could be useful in designing future combination therapies for CLL.