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Background Immune checkpoint inhibitors (ICIs) to date have demonstrated limited activity in advanced ovarian cancer (OC). Folate receptor alpha (FRα) is overexpressed in the majority of OCs and presents an attractive target for a combination immunotherapy to potentially overcome resistance to ICI in OCs. The current study sought to examine clinical and immunologic responses to TPIV200, a multiepitope FRα vaccine administered with programmed death ligand 1 (PD-L1) inhibitor durvalumab in patients with advanced platinum-resistant OC. Methods Following Simon two-stage phase II trial design, 27 patients were enrolled. Treatment was administered in 28-day cycles (intradermal TPIV200 and granulocyte-macrophage colony-stimulating factor (GM-CSF) for 6 cycles and intravenous durvalumab for 12 cycles). Primary endpoints included overall response rate and progression-free survival at 24 weeks. Translational parameters focused on tumor microenvironment, PD-L1 and FRα expression, and peripheral vaccine-specific immune responses. Results Treatment was well tolerated, with related grade 3 toxicity rate of 18.5%. Increased T cell responses to the majority of peptides were observed in all patients at 6 weeks (p<0.0001). There was one unconfirmed partial response (3.7%) and nine patients had stable disease (33.3%). Clinical benefit was not associated with baseline FRα or PD-L1 expression. One patient with prolonged clinical benefit demonstrated loss of FRα expression and upregulation of PD-L1 in a progressing lesion. Despite the low overall response rate, the median overall survival was 21 months (13.5–∞), with evidence of benefit from postimmunotherapy regimens. Conclusions Combination of TPIV200 and durvalumab was safe and elicited robust FRα-specific T cell responses in all patients. Unexpectedly durable survival in this heavily pretreated population highlights the need to investigate the impact of FRα vaccination on the OC biology post-treatment.

Abstract Background Awareness of burnout has led residency programs to seek interventions to promote well-being, resiliency, camaraderie and social network development. Limited evidence exists on the efficacy of specific interventions. This study evaluated the efficacy of an emergency medicine residency program’s semi-annual retreat using serial administration of the Maslach burnout index and resident well-being survey. Methods Surveys were administered to all emergency medicine residents (n = 25) in July 2018 and before and after fall 2018 and winter 2019 retreats. Retreats included a meal, team building, and social networking opportunities (bowling, softball, snow tubing, and sledding). Comparisons of responses between baseline, pre-retreat, and post-retreat were evaluated using two-sample t, Wilcoxon rank sum, and Fisher exact tests. Results Sixteen emergency medicine residents (64%) responded at baseline. Response rates on subsequent surveys ranged from 14 (56%) to 21 (84%). Nineteen percent of residents exhibited burnout at baseline. This peaked at 36% pre-winter retreat. Burnout decreased after each retreat (fall: 29–6%, winter: 36–13%). Mean Maslach burnout index subscores for emotional exhaustion (13 to 9) and depersonalization (7 to 5) decreased from baseline to post-fall retreat, but neither changed significantly over the entire study period (emotional exhaustion: 13 to 12, depersonalization: 7 to 6). Resident well-being survey pre- and post-retreat responses were similar on all items. Conclusion Meaningful, but not statistically significant differences were detected on the Maslach burnout index and resident well-being survey in association with a retreat. Mean emotional exhaustion, depersonalization and burnout decreased after retreats. Larger studies would provide further insight into the significance of these trends.

LBA110 Background: There are limited data on COVID-19 in patients with cancer. We characterize the outcomes of patients with cancer and COVID-19 and identify potential prognostic factors. Methods: The COVID-19 and Cancer Consortium (CCC19) cohort study includes patients with active or prior hematologic or invasive solid malignancies reported across academic and community sites. Results: We included 1,018 cases accrued March-April 2020. Median age was 66 years (range, 18-90). Breast (20%) and prostate (16%) cancers were most prevalent; 43% of patients were on active anti-cancer treatment. At time of data analysis, 106 patients (10.4%) have died and 26% met the composite outcome of death, severe illness requiring hospitalization, and/or mechanical ventilation. In multivariable logistic regression analysis, independent factors associated with increased 30-day mortality were age, male sex, former smoking, ECOG performance status (2 versus 0/1: partially adjusted odds ratio (pAOR) 2.74, 95% CI 1.31-5.7; 3/4 versus 0/1: pAOR 5.34, 95% CI 2.44-11.69), active malignancy (stable/responding, pAOR 1.93, 95% CI 1.06-3.5; progressing, pAOR 3.79, 95% CI 1.78-8.08), and receipt of azithromycin and hydroxychloroquine. Tumor type, race/ethnicity, obesity, number of comorbidities, recent surgery, and type of active cancer therapy were not significant factors for mortality. Conclusions: All-cause 30-day mortality and severe illness in this cohort were significantly higher than previously reported for the general population and were associated with general risk factors as well as those unique to patients with cancer. Cancer type and treatment were not independently associated with increased 30-day mortality. Longer follow-up is needed to better understand the impact of COVID-19 on outcomes in patients with cancer, including the ability to continue specific cancer treatments.

11539 Background: Ripretinib is a novel switch-control TKI that broadly inhibits KIT and PDGFRA kinase signaling. In INVICTUS (NCT03353753), a randomized, double-blind, placebo (PBO)-controlled trial of ripretinib in ≥4th-line advanced GIST, ripretinib reduced the risk of disease progression or death by 85% vs PBO with a favorable overall safety profile. Common ( > 20%) adverse events (AEs) included, but were not limited to, alopecia and PPES. Exploratory analyses evaluated the impact of alopecia and PPES on quality of life (QoL). Methods: Patients (pts) with advanced GIST previously treated with at least imatinib, sunitinib, and regorafenib were randomized (2:1) to ripretinib 150 mg QD or PBO. AEs were graded using CTCAE v4 and PROs collected using EQ-5D-5L (EQ5D) and EORTC QLQ-C30 (C30). Repeated measures (RM) models assessed the impact of alopecia and PPES on 5 PROs (EQ5D visual analogue scale; and C30 physical functioning, role functioning, and the overall health and overall QoL questions) within the ripretinib arm. Fixed effects were sex, alopecia/PPES, and ECOG scores at baseline. Results: 128/129 randomized pts received treatment (85 ripretinib 150 mg QD; 43 PBO). Alopecia, regardless of causality, occurred in 44 (51.8%) on ripretinib (34 [40.0%] grade 1; 10 [11.8%] grade 2) and 2 (4.7%) on PBO (both grade 1). PPES occurred in 18 (21.2%) on ripretinib (11 [12.9%] grade 1; 7 [8.2%] grade 2); none on PBO. The median times in days to first occurrence and worst severity grade with ripretinib were 57.0 and 62.5 for alopecia; 56.5 and 57.0 for PPES. The RM models showed a slight trend towards improvement in PRO score over time for pts with alopecia; the only association reaching a P-value of < 0.05 was between alopecia and increased overall QoL. None of the associations between PPES and PRO scores reach P < 0.05. All PRO p-values are nominal, and no statistical significance is being claimed. Conclusions: Ripretinib had a favorable overall safety and tolerability profile. When stratified by alopecia and PPES, patient-reported assessments of function, overall health, and overall QoL were maintained over time. For both alopecia and PPES, onset and maximum severity occurred almost simultaneously, indicating that these events generally did not progressively worsen. These results suggest that alopecia and PPES are manageable and do not have a negative effect on function, overall health, and QoL. Clinical trial information: NCT03353753 .

11535 Background: Ripretinib is a novel switch-control tyrosine kinase inhibitor (TKI) that broadly inhibits KIT and PDGFRA kinase signaling through a dual mechanism of action. In INVICTUS (NCT03353753), a randomized, double-blind, placebo-controlled trial of ripretinib in ≥4th-line advanced GIST, ripretinib reduced the risk of disease progression or death by 85% vs placebo and had a favorable overall safety profile in patients previously treated with ≥3 prior TKIs. Methods: As part of the INVICTUS trial, patient reported outcome (PRO) measures were collected using EQ-5D-5L (EQ5D) and EORTC QLQ-C30 (C30). In prespecified and additional analyses, ANCOVA models were built to compare changes from baseline to cycle 2 day 1 (C2D1) for PRO measures within the ripretinib and placebo arms and determine the difference between treatment arms. PRO measures included the EQ5D visual analogue scale (VAS) and the C30 physical functioning (PF) and role functioning (RF) scales (all scores range from 0–100; higher scores are better). The C30 overall health and overall QoL questions were also assessed (scores range from 1–7; higher scores are better). Fixed effects included treatment arm, number of previous anticancer treatments (3 vs ≥4), and ECOG score at baseline (0 vs 1/2). Results: Overall, 129 patients were randomized and 128 received treatment (85 to ripretinib 150 mg QD; 43 to placebo). All PRO p-values are nominal, and no statistical significance is being claimed. VAS scores improved an average 3.7 points from baseline to C2D1 with ripretinib vs an average decline of 8.9 with placebo (P = 0.004; improvement or no change, 67% vs 41% of patients, respectively). Similarly, the average PF score improved 1.6 points with ripretinib and decreased 8.9 with placebo (P = 0.004; improvement or no change, 68% vs 44%). RF scores also improved an average of 3.5 points with ripretinib vs a decrease of 17.1 with placebo (P = 0.001; improvement or no change, 77% vs 50%). For the overall health and overall QoL questions, scores increased with ripretinib an average of 0.20 and 0.28, respectively, and decreased 0.78 and 0.76 with placebo (both P = 0.001; improvement or no change, 74% vs 47% and 79% vs 59%, respectively). Conclusions: Based on the 5 PRO measures assessed, when compared with placebo and best supportive care, ripretinib provided patient-benefit in advanced GIST with PRO measures of role and physical function, VAS, overall health, and overall QoL remaining stable. Clinical trial information: NCT03353753 .

e20044 Background: Primary Cutaneous Diffuse Large B-cell Lymphoma, Leg-type (PCDLBCL) is a rare lymphoma comprising 4% of all cutaneous lymphomas with an aggressive clinical course. We investigated disease characteristics and outcomes among patients PCDLBCL. Methods: Following IRB approval, we identified patients retrospectively with PCDLBCL treated at the Mayo Clinic Cancer Center 1998-2019. Results: 45 pts were identified with a median age of 71 years (Range- 48-95) and 28 (62%) were female. Disease locations were legs (62%), arms (22%), head (11%), trunk (2%) and multiple sites (2%). At diagnosis, (51%) had a single lesion, (29%) had multiple lesions in 1-2 contiguous regions, (16%) had multiple lesions in non-contiguous regions or > 2 regions and data was not available (4%). Immunohistochemistry showed positive staining for BCL-2 (92%), BCL-6 (76%), c-MYC (62%), MUM1 (95%), CD10 (11%), and cytoplasmic IgM (8/9- 89%). By Han’s criteria, (95%) had activated B cell lymphoma (ABC). Median Ki-67 was 90% (range, 50,100%). 9/12 (75%) were positive for MYD88 L265P mutation. 13/21 (62%) were double expressor and 3/22 (14%) had double hit lymphoma. 37/45 (82%) had ECOG < 2. LDH was elevated in 13/37 (35%). The median number of therapies was 1 (range; 1-11). The initial treatments were chemo-radiation (30%), chemo alone (38%), rituximab alone (11%), radiation (RT) alone (16%), rituximab-RT (2.5%), and surgical (2.5%). The median follow-up time for the whole cohort was 80 months (95% CI; 32, 169). The median progression free survival and overall survival (OS) were 20 months (95% CI; 12, 34) and 80 months (95% CI; 48, 119). 22/45 (49%) are alive. The cause of death was disease-related in 11/23 (48%). The median number of relapses was 1 (range; 0, 11) with (60%) relapsed after first line. 4/45 pts had autologous stem cell transplant after relapse. 7/45 (16%) had a systemic relapse at a median time of 35 months from diagnosis (range; 16, 112). Age above 60 years was associated with worse OS; 70 months (95% CI; 30, 99) vs NR (95% CI; 135, NR), p = 0.025. ECOG performance status < 2 was associated with better OS, NR months (95% CI; 80, NR) vs 48 months (95% CI; 3.3, 88),p = 0.0003. 1 pt received Ibrutinib on 11th relapse and had 3 years of PFS. Conclusions: PCDLBCL is predominantly ABC type, affects elderly pts and is characterized by multiple cutaneous relapses followed in some cases by systemic relapses. Increased age and poor performance status had a negative impact on OS. High incidence of MYD88 L265P mutation is observed in PCDLBCL similar to immune-privileged site lymphomas.

e20036 Background: Hepatosplenic T cell lymphoma (HSTL) is a rare subtype of mature T cell lymphomas accounting for less than 1 percent of non-Hodgkin lymphomas. it has been associated with poor prognosis. It typically involves sinusoids in the spleen, liver, and bone marrow. Methods: Following IRB approval, we retrospectively evaluated patients with HSTL treated at the Mayo Clinic Cancer Center 1996-2019. Kaplan-Meier survival analysis and univariate analysis to identify prognostic factors were performed. We investigated clinical characteristics and outcomes among patients with HSTL. Results: 22 patients (15 males) with median age of 45.5 years (range- 15.5-80.6) were identified. The majority of patients had B symptoms (12/22), cyotpenias (20/22), massive splenomegaly (16/22), liver involvement (13/22), and/or bone marrow involvement (14/22). Additionally, 42% tested positive for peripheral blood involvement and 8/22 (36%) were on chronic immunosuppression related to solid organ transplant (2), inflammatory bowel disease (2), and rheumatologic disorders (4). Phenotypically, the majority of patients were positive for gamma/delta (18/22), isochromosome 7q (8/13), and 4/9 (44%) tested positive for trisomy 8. Initial therapies included CHOP/CHOEP (14), ICE (2), EPOCH (1), pentostatin (1), and radiation (1). The median follow-up was 33 months (range 2,137). Progression free survival and overall survival (OS) were 9.5 months (95% CI; 1.8, 16.3) and 12 months (95% CI; 4.9, 18.5) respectively. 10/22 (45%) underwent splenectomy with one patient receiving splenectomy alone as treatment. 8/22 (36%) had stem cell transplant (SCT- 5 allogeneic and 3 autologous). Out of the 22 patients 4 (18%) were long-term survivors with 55, 74, 95, and 137 months; 3/4 had splenectomy at diagnosis and 2/4 had allogeneic SCT. The longest survivor had splenectomy only. Liver involvement was associated with worse OS; 10 months (95% CI; 1.6, 18) vs 35 months (95% CI; 4, NR), p = 0.036. Immune suppression at diagnosis was associated with worse OS; 5 months (95% CI; 1.3, 18) vs 18 months (95% CI; 9, 74), p = 0.036. A trend for better OS was seen with splenectomy and SCT. Conclusions: HSTL is a rare lymphoma with poor prognosis. Long-term survival was seen in 18% only. Liver involvement and immune suppression had a negative impact on OS. A larger cohort is needed to better evaluate the impact of different treatment options.

6016 Background: The role of HIPEC for recurrent EOC is not well defined. The aim of this phase II study was to determine the proportion of pts without evidence of disease progression at 24 months post SCS +/- intraoperative carboplatin HIPEC. Methods: After SCS to ≤ 0.5 cm residual visible disease pts were intraoperatively randomized to carboplatin HIPEC (800mg/m2 for 90 minutes) or no HIPEC. The HIPEC arm received 5 additional and the standard arm received 6 postoperative cycles of IV platinum-based chemotherapy without maintenance treatment. Based on an exact binomial single stage “pick the winner” design, each arm is considered “winner” if ≥ 17/49 pts are without evidence of disease progression at 24 months post SCS. Secondary objectives include postoperative grade ≥ 3 toxicity and complications within 4 weeks post SCS, and pharmacokinetics of carboplatin HIPEC. Results: Of 98 pts, 49 (50%) were randomized to the HIPEC arm. The arms were well balanced for age, stage, histology, BRCA mutation status, prior chemotherapy, and disease-free interval. Complete gross SCS was achieved in 94% of the standard and 82% of the HIPEC arm (p = 0.12). Bowel resection was performed more frequently in the standard (65%) compared to the HIPEC arm (37%; p = 0.008). Median operative time was shorter in the standard (296 minutes) compared to the HIPEC arm (475 minutes; p < 0.001). There was no perioperative mortality and no difference in use of ostomies, length of stay or postoperative toxicity. At a median follow-up of 27.7 months (range: 8.8-81.8 months) 70 of 98 pts progressed and 26 died with a median progression free survival (PFS) of 14.3 months (12.1-16 months) and a median overall survival (OS) of 55.2 months (47.7-not reached). At 24 months post SCS 32 pts progressed within 24 months in the standard versus 35 in the HIPEC arm. There was no statistically significant difference in median PFS (15.4 vs 12.3 months, p = 0.173) or median OS (69.2 vs 53.1 months, p = 0.317) between arms. These are preliminary efficacy estimates as 83/98 pts have a minimum of 24 months follow-up. Conclusions: The HIPEC arm did not reach the predefined “winner” endpoint; the standard arm is still undetermined as 6 pts did not reach 24 months follow-up. No perioperative mortality, and no increased perioperative morbidity or toxicity was seen with HIPEC. SCS with carboplatin HIPEC followed by 5 cycles of platinum-based chemotherapy was not superior to SCS without HIPEC followed by 6 cycles of platinum-based chemotherapy. Clinical trial information: NCT01767675.

4108 Background: Circulating tumor DNA (ctDNA) testing can be used for the assessment of molecular residual disease (MRD) in patients with early-stage or advanced colorectal cancer (CRC). Prospective evaluation of this methodology in clinical practice has been limited to-date. Methods: A personalized and tumor-informed multiplex PCR assay (Signatera 16-plex bespoke mPCR NGS assay) was used for the detection and quantification of ctDNA for MRD assessment. We analyze and present results from an ongoing early adopter program of ctDNA testing across the spectrum of CRC management. Results: Here we present a total of 250 patients with colon (n=200), rectal (n=40), and other lower gastrointestinal cancers (n =10; anal, appendiceal, small bowel). MRD positivity rates and ctDNA quantification (mean tumor molecules/mL) are shown in Table. ctDNA detection was significantly associated with stage of disease (p<0.0001 Chi-square: 70.33). Additionally, in patients with radiologically measurable active metastatic disease, ctDNA detection rate was 100%. On the contrary, patients with advanced/metastatic disease who had partial response to treatment or no evidence of disease (NED) showed 28.5% and 19.2% of ctDNA-positivity, respectively. Conclusions: This is the first large, real-world study reporting on the results from a clinically validated MRD assay. For the first time we delineate MRD rates and quantify ctDNA concentration in patients with early-stage and advanced CRC. Furthermore, we provide an initial readout that effective ongoing treatment in patients with CRC may be correlated with ctDNA clearance. Ongoing analysis expanded to a cohort of 1200 clinical cases including correlation with genomic and serial testing will be presented. [Table: see text]