Stewart, A. Keith

INTRODUCTION: To report the prevalence and outcomes of unselected pancreatic cancer (PC) patients with pathogenic/likely pathogenic germline variants (PGVs) detected using a universal testing approach. METHODS: We undertook a prospective, multisite study of germline sequencing using a >80 gene next-generation sequencing platform among 250 patients with PC (not selected for age or family history of cancer) between April 1, 2018, and March 31, 2020. Demographic, tumor characteristics, and clinical outcomes were compared between PGV carriers and noncarriers. RESULTS: Of 250 patients, the mean age was 65 years (SD 8.7), 56% was male, 83.6% was White, and 65.6% had advanced disease (stages III and IV). PGVs were found in 15.2% (N = 38) of patients, and 2 patients had more than 1 PGV. Variants of uncertain significance were found in 44.4% (N = 111). Family history of cancer (odds ratio: 2.36, 95% confidence interval: 1.14–5.19, P = 0.025) was associated with a higher risk of PGV. In a median follow-up of 16.5 months, the median overall survival was 16.8 months in PGV carriers compared with 16.5 months in noncarriers (hazard ratio: 0.51, 95% confidence interval: 0.25–1.01, P = 0.05). Higher levels of carbohydrate antigen 19-9 and advanced disease stages (III and IV) were associated with worse outcomes in both groups. Overall, 68% of PGV carriers had mutations in homologous recombination repair genes, including BRCA1 , BRCA2 , PALB2 , ATM , CHEK2 , NBN , and RAD51C . DISCUSSION: Universal multigene panel testing in PC reveals that 1 in 6 patients are carriers of PGV. Multigene germline testing should be used to aid in treatment selection, prognostication, and familial cancer counseling.

8542 Background: Clonal hematopoiesis of indeterminate potential (CHIP) is defined by the presence of leukemia-associated somatic mutations in clonally expanded hematopoietic stem cells with a VAF of ≥2%. CHIP has been associated with myeloid malignancies and increased all cause mortality largely from atherovascular disease. The prevalence and impact of CHIP in patients with myeloma (MM) is yet to be defined. Aims: Evaluate the prevalence and significance of CHIP in 101 lenalidomide exposed patients with multiple myeloma. Methods: 101 MM patients, the majority exposed to > 2 years of lenalidomide (Len), with stored mononuclear blood samples were identified for Next Generation Sequencing (NGS) using a panel encompassing 42 gene mutations associated with CHIP. Electronic medical records were reviewed and outcomes of secondary malignancy, macrocytosis, thrombosis and mortality were extracted. Results: Thirty of 101patients were found to have CHIP with the most frequent mutations: DNMT3A (12%), TET2 (5%), and TP53 (4%). One third of patients with CHIP had > 1 mutation (37%). At 68 months median follow up over a quarter of patients experienced thrombosis (31%) and 13% developed subsequent malignancy/premalignant condition including myelodysplastic syndrome (3%). There was no significant difference in age, gender, duration of Len prior to NGS testing, thrombosis complication, or survival in those with versus without a CHIP mutation. At last F/U 30% had died, 25% remained on therapy, 27% were on maintenance therapy and 11% were on observation alone. Conclusions: CHIP mutations are common in plasma cell neoplasms, with 30% of patients in this study retrospectively found to have CHIP mutations by NGS testing. CHIP mutations have been associated with cardiovascular events and malignancy development, however no associations were identified in this small study. Limitations to this study include small sample size, retrospective nature and duration of follow up. Further study of this very common finding in MM patients regarding timing of development and subsequent impact of these mutations could help risk stratify and inform therapy selection. [Table: see text]

e19132 Background: The Functional Assessment of Cancer Therapy–General has an item about patient tolerability of treatment: “I am bothered by side effects of treatment” (GP5). We examined the predictive value of this single item for early treatment discontinuation in clinical trials. Methods: GP5 level prior to protocol therapy (rated using a 5-point Likert scale) and treatment start/end dates and off treatment reason data at each treatment phase were drawn from five phase III clinical trials conducted by ECOG-ACRIN. In the present analysis, GP5 was dichotomized as 0 = “Not at all”/“A little bit” and 1 = “Somewhat”/“Quite a bit”/“Very Much”. Early treatment discontinuation was defined either as receiving less than protocol specified cycles of treatment when maximum cycles specified in the protocol (E1A06 induction, E1912 induction, E1609 induction, E1105 induction, E5103 adjuvant), analyzed using logistic regression via odds ratio [OR]), or treatment cessation for reasons other than progressive disease or death when treatment continued until progression or intolerability (E1A06 maintenance, E1912 maintenance, E1609 maintenance, E1105 maintenance), analyzed using Cox proportional hazard model via hazard ratio [HR]. Results: GP5 prior to treatment was significantly associated with early discontinuation of E1A06 maintenance, E1609 maintenance, E1912 maintenance, and E1912 induction. No significant association was found for other therapies examined in the study. Conclusions: High GP5 level prior to treatment is associated with higher likelihood of early treatment discontinuation in patients who have received previous treatment. The limited predictive value of GP5 for treatment naïve patients is more limited, serial on-treatment assessment should be considered in this setting. Clinical trial information: NCT00602641 . [Table: see text]

8013 Background: Obatoclax mesylate (GX15-070MS) is a BH3 mimetic that inhibits Bcl-2 protein family members including MCL-1, a dominant target in myeloma (MM). Obatoclax (OBX) inhibited viability of 14 MM cell lines (mean IC50 215 nM) and primary MM samples while exhibiting pre clinical synergy with bortezomib (BTZ). Sensitivity correlated with basal levels of Mcl-1 and Bcl-XL, but not Bcl2, Bim, Bax or Bak expression. Methods: We report a phase I trial of OBX in combination with BTZ. Eligibility required measureable disease, > 1 prior MM therapy, ≤10 cycles of prior BTZ and did not progress on prior BTZ therapy, creatinine ≤2 ULN. Starting dose level 1 was OBX 14 mg/m2 24-hour continuous iv. infusion days 1, 8, 15 of a 21-day cycle. BTZ given at 1.3mg/m2 iv. days 1, 4, 8 and 11. After protocol amendment OBX level 1 dosing was 30 mg/m2, level 2 was 40 mg/m2 IV both by continuous 3 hour infusion days 1, 8 and 15 on a 21 day schedule. Pre med. with famotidine was required. Results: Eleven patients were accrued, median age 62 (range: 46-77), median time from diagnosis was 4.7 years. Median of 2.5 cycles (range: 1-10). Median follow-up for patients still alive is 11.6 months (range: 0.9-35.5). At dose level 1, there were 2 DLTs. After amendment 8 patients were accrued (3 hour infusion): 4 at amended dose level 1 and 4 at dose level 2. All patients are now off treatment. 10 patients are evaluable for response: 2 patients at original dose level 1 (2 PR), 3 patients at dose level 1 (2 PR, 1 MR), no patients at dose level 2 responded: overall PR of 40%, clinical benefit response in 50% (95% CI: 19-81%). 6 patients had disease progression and 2 patients died. 4 DLTs were seen: at original dose level 1 grade 4 thrombocytopenia and delay of therapy > 15 days. At dose level 2, 1 patient had grade 3 somnolence, a 2nd patient grade 3 euphoria and grade 4 thrombocytopenia. No DLTs were seen at amended dose level 1. Common adverse events of any grade included GI, hematologic and neurologic e.g. euphoria, decreased level of consciousness, psychosis, speech. Conclusions: In summary MTD is OBX 30mg/m2 by 3 hour iv infusion once weekly, BTZ 1.3 mg/m2 days 1,4,8, and 11. Major toxicities were central neurologic and hematologic. This P2C consortium study was supported by NCI N01-CM62205.

BACKGROUNDNVP‐AUY922 (AUY; Luminespib) with or without bortezomib showed preclinical activity against multiple myeloma (MM) cells. This phase 1/1B study assessed NVP‐AUY922 alone and with bortezomib in patients with relapsed or refractory MM.METHODSDose escalation was guided by an adaptive Bayesian logistic regression model. In phase 1, patients who progressed after 2 to 4 prior therapies received NVP‐AUY922 intravenously once weekly. In phase 1B, patients who progressed after 2 or fewer prior therapies received NVP‐AUY922 plus bortezomib. The primary objective was to determine the maximum tolerated dose (MTD) of NVP‐AUY922.RESULTSTwenty‐four patients received NVP‐AUY922 monotherapy at doses of 8 to 70 mg/m2. One dose‐limiting toxicity (DLT) was observed (grade 3 blurred vision at 70 mg/m2); no MTD was reached. The recommended phase 2 dose was 70 mg/m2. The most frequent drug‐related adverse events (AEs) were diarrhea, nausea, and ocular toxicities. Grade 3/4 AEs were uncommon (<10%). Eight patients discontinued treatment because of AEs; 5 had ocular toxicities (≥45 mg/m2). The best response was stable disease in 66.7% of the patients. There were no partial or complete responses. Five patients received NVP‐AUY922 (which was started at 50 mg/m2) plus bortezomib (1.3 mg/m2). Three of these patients experienced DLT. No further dose escalation was performed; the MTD for NVP‐AUY922 plus bortezomib was not established.CONCLUSIONSThis study showed disease stabilization with NVP‐AUY922 in patients with relapsed or refractory MM. The MTD for NVP‐AUY922 was not reached, but reversible ocular toxicity has been reported at high dose levels. Bortezomib at the standard recommended dose plus NVP‐AUY922 was not tolerated. Cancer 2015;121:2185–2192. © 2015 American Cancer Society.