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No approved medical therapies prevent progression of low-grade prostate cancer. Rapamycin inhibits cell proliferation and augments immune responses, producing an antitumor effect. Encapsulated rapamycin (eRapa) incorporates rapamycin into a pH-sensitive polymer, ensuring consistent dosing. Here, we present results from a phase I trial evaluating the safety and tolerability of eRapa in patients with prostate cancer. Patients with Gleason ≤7 (3+4) disease (low and intermediate risk) under active surveillance were enrolled in a 3+3 study with three eRapa dosing cohorts (cohort 1, 0.5 mg/week; cohort 2, 1 mg/week; and cohort 3, 0.5 mg/day). Patients were treated for 3 months and followed for an additional 3 months to assess safety, pharmacokinetics, quality of life (QoL), immune response, and disease progression. Fourteen patients (cohort 1, n = 3; cohort 2, n = 3; and cohort 3, n = 8) were enrolled. In cohort 3, one dose-limiting toxicity (DLT; neutropenia) and two non-DLT grade 1–2 adverse events (AE) occurred that resulted in patient withdrawal. All AEs in cohorts 1 and 2 were grade 1. Peak serum rapamycin concentration was 7.1 ng/mL after a 1 mg dose. Stable trough levels (∼2 ng/mL) developed after 48–72 hours. Daily dosing mildly worsened QoL, although QoL recovered after treatment cessation in all categories, except fatigue. Weekly dosing increased naïve T-cell populations. Daily dosing increased central memory cell populations and exhaustion markers. No disease progression was observed. In conclusion, treatment with eRapa was safe and well-tolerated. Daily dosing produced higher frequencies of lower grade toxicities and transient worsening of QoL, while weekly dosing impacted immune response. Future studies will verify clinical benefit and long-term tolerability.Prevention Relevance: There is an unmet medical need for a well-tolerated treatment capable of delaying progression of newly diagnosed low-grade prostate cancer. This treatment would potentially obviate the need for future surgical intervention and improve the perception of active surveillance as a more acceptable option among this patient population.

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Introduction The 2020 Commission on Cancer accreditation standards 5.7 and 5.8 address total mesorectal excision for rectal cancer and lymph node sampling for lung cancer. The purpose of this review was to assess our institution’s compliance with these operative standards, which will be required in 2022 and 2023, and provide recommendations to other military training facilities seeking to comply with these standards. Materials and Methods A 2018-2020 single institution chart review was performed of operative and pathology reports. Identified deficits were addressed in meetings with colorectal and thoracic surgery leadership, and cases were followed to reassess compliance. Results A total of 12 rectal and 48 lung cancer cases met the inclusion criteria and were examined. Pre-intervention compliance for standards 5.7 and 5.8 was 58% and 35%, respectively, because of inadequate synoptic reporting and lymph node sampling. After intervention, compliance was 100%. Conclusions Our institution requires changes to comply with new standards, including in areas of documentation and systematic pulmonary lymph node sampling. We provide lessons learned from our own institutional experience, including practical tips and recommendations to achieve compliance. All military training facilities performing lung and rectal oncologic resections should conduct an internal review of applicable cases in preparation for upcoming American College of Surgeons Commission on Cancer site visits.

Background Melanoma therapy has changed dramatically over the last decade with improvements in immunotherapy, yet many patients do not respond to current therapies. This novel vaccine strategy may prime a patient’s immune system against their tumor and work synergistically with immunotherapy against advanced-stage melanoma. Methods This was a prospective, randomized, double-blind, placebo-controlled, phase IIb trial of the tumor lysate, particle-loaded, dendritic cell (TLPLDC) vaccine administered to prevent recurrence in patients with resected stage III/IV melanoma. Patients were enrolled and randomized 2:1 to the TLPLDC vaccine or placebo (empty yeast cell wall particles and autologous dendritic cells). Both intention-to-treat (ITT) and per treatment (PT) analyses were predefined, with PT analysis including patients who remained disease-free through the primary vaccine/placebo series (6 months). Results A total of 144 patients were randomized (103 vaccine, 41 control). Therapy was well-tolerated with similar toxicity between treatment arms; one patient in each group experienced related serious adverse events. While disease-free survival (DFS) was not different between groups in ITT analysis, in PT analysis the vaccine group showed improved 24-month DFS (62.9% vs. 34.8%, p = 0.041). Conclusions This phase IIb trial of TLPLDC vaccine administered to patients with resected stage III/IV melanoma shows TLPLDC is well-tolerated and improves DFS in patients who complete the primary vaccine series. This suggests patients who do not recur early benefit from TLPLDC in preventing future recurrence from melanoma. A phase III trial of TLPLDC + checkpoint inhibitor versus checkpoint inhibitor alone in patients with advanced, surgically resected melanoma is under development. Trial Registration NCT02301611. Supplementary information The online version contains supplementary material available at (10.1245/s10434-021-09709-1).

Lymphadenectomy (LND) is recommended following surgical resection of ≥ T1b gallbladder cancer (GBC). However, frequency and stage-specific survival benefits of LND remain unclear. The National Cancer Database (NCDB; 2006-15) was queried for resected pathologic stage I–III GBC. LND performance, predictors of receiving LND, and LND association with overall survival (OS) were assessed. Of 2302 total patients, 1343 (58.3%) underwent LND. Patients who underwent LND were younger and more frequently had private health insurance, a negative surgical margin, higher pathologic T stage, and received adjuvant chemotherapy (all p < 0.001). LND rates were highest at academic centers (70.1%) relative to all other facility types (p < 0.001). LND was independently associated with improved OS [hazard ratio (HR) 0.52, 95% confidence interval (CI) 0.44–0.61]. LND was associated with improved OS for pT1b, pT2, and pT3 patients (all p < 0.05) on univariate analysis. LND was independently associated with improved OS in pT2 (HR 0.44, CI 0.35–0.56) and pT3 (HR 0.54, CI 0.43–0.69) patients. LND is associated with a 48% reduction in risk of death in patients with resectable non-metastatic GBC, with greatest impact in pT2–3 patients. Patients without LND have similar OS to patients with node-positive disease, highlighting the importance of LND. Underutilization of LND likely results in undertreatment of patients with undiagnosed nodal disease, which may contribute to unfavorable oncologic outcomes.

Background Colorectal cancer (CRC) tumor microenvironment (TME) characteristics, such as tumor infiltrating lymphocyte (TIL) densities and PD-L1 status, are predictive of recurrence, disease-free survival, and overall survival. In many malignancies, TME characteristics are also predictive of response to immunotherapy. As window of opportunity studies using neoadjuvant immunotherapy become more common and treatment guidelines incorporate TME features, accurate assessment of the pre-treatment TME using the biopsy specimen is critical. However, no study has thoroughly evaluated the correlation between the TMEs of the biopsy and resection specimens. Methods We conducted a retrospective analysis of patients with stage I–III CRC with matched biopsy and resection specimens. CD3+, CD4+, CD8+, and FoxP3+ lymphocyte populations at the center of tumor (CT) and invasive margin (IM) and tumor PD-L1 status in the biopsy and resection specimens were evaluated. TIL populations were compared using Mann–Whitney U tests or Student’s t tests and correlated using Pearson r. Results CD3+ and CD4+ densities were significantly higher in the CT of the biopsy relative to the resection specimen Comparing biopsy and resection specimens, no TIL population at either the CT or IM had a correlation coefficient > 0.5. Determining PD-L1 status based on biopsy tissue resulted in a sensitivity of 37.1%, specificity of 81.4%, and accuracy of 61.5%. Conclusions These findings demonstrate significant discordance between the TME of the biopsy and resection specimens. Caution should be used when basing treatment decisions on pre-treatment endoscopic biopsy findings and when interpreting changes in the TME between pre-treatment biopsy and resection specimens after neoadjuvant therapy. Electronic supplementary material The online version of this article (10.1007/s00262-020-02784-5) contains supplementary material, which is available to authorized users.

Adjuvant chemotherapy (AC) is recommended following surgical resection of gallbladder cancer regardless of stage. However, stage-specific benefits of AC in gallbladder cancer are unclear. Patients with resected pathologic stage I–III gallbladder cancer were identified using the 2006–2015 National Cancer Database. Utilization trends, predictors of use, and impact of AC on overall survival (OS) were determined. A total of 5656 patients were included. Use of AC increased from 9.9% in 2006 to 24.2% in 2015 (OR 2.91; 95% CI 2.06–4.09; p

A randomized, double-blind, placebo-controlled phase 2b trial of the tumor lysate, particle-loaded, dendritic cell (TLPLDC) vaccine was conducted in patients with resected stage III/IV melanoma. Dendritic cells (DCs) were harvested with and without granulocyte-colony stimulating factor (G-CSF). This analysis investigates differences in clinical outcomes and RNA gene expression between DC harvest methods.The TLPLDC vaccine is created by loading autologous tumor lysate into yeast cell wall particles (YCWPs) and exposing them to phagocytosis by DCs. For DC harvest, patients had a direct blood draw or were pretreated with G-CSF before blood draw. Patients were randomized 2:1 to receive TLPLDC or placebo. Differences in disease-free survival (DFS) and overall survival (OS) were evaluated. RNA-seq analysis was performed on the total RNA of TLPLDC + G and TLPLDC vaccines to compare gene expression between groups.144 patients were randomized: 103 TLPLDC (47 TLPLDC/56 TLPLDC + G) and 41 placebo (19 placebo/22 placebo + G). Median follow-up was 27.0 months. Both 36-month DFS (55.8% vs. 24.4% vs. 30.0%, p = 0.010) and OS (94.2% vs. 69.8% vs. 70.9%, p = 0.024) were improved in TLPLDC compared to TLPLDC + G or placebo, respectively. When compared to TLPLDC + G vaccine, RNA-seq from TLPLDC vaccine showed upregulation of genes associated with DC maturation and downregulation of genes associated with DC suppression or immaturity.Patients receiving TLPLDC vaccine without G-CSF had improved OS and DFS. Outcomes remained similar between patients receiving TLPLDC + G and placebo. Direct DC harvest without G-CSF had higher expression of genes linked to DC maturation, likely improving clinical efficacy.

The coronavirus disease 2019 pandemic has profoundly impacted surgical education. We assessed resident perceptions of our virtual academic program, which consists of daily lectures or case conferences held via a videoconferencing platform.A survey evaluating attitudes and practices for virtual academics was administered to general surgery residents. A focus group was conducted to identify benefits, barriers to engagement, and opportunities for improvement for virtual education. A total of 19 residents completed the education survey, and seven residents participated in the focus group.While expressing preference toward in-person academics (84.2%), residents felt the virtual academics were of good quality (median rating 4/5) and preferred virtual academics to no academic sessions (94.7%). Of respondents, 57.9% believe that the coronavirus pandemic negatively impacted their surgical education. They believe their American Board of Surgery In-Training Examination preparation was not impacted. Residents preferred using a computer over a phone for academics (79% versus 16%). The focus group identified the benefits of virtual academics, including the ability to participate while away and having recordings available. Areas for improvement included reinforcement of protected time for academics, requiring cameras be on, increasing in-lecture polls, and creation of an online repository of recordings for review. Residents hoped a virtual component of academics and recordings would continue past the pandemic.Although virtual academics are not the preferred mode of learning in our residency, there are multiple unintended benefits. We recommend a hybrid academic model with in-person didactics and recorded video for later review.

BackgroundThe tumor lysate, particle-loaded, dendritic cell (TLPLDC) vaccine is an autologous tumor vaccine that decreased recurrence in stage III/IV melanoma when granulocyte-colony stimulating factor (G-CSF) was not used to harvest the dendritic cells in a randomized phase 2B adjuvant trial.1The tumor lysate (TL) particle only (TLPO) vaccine utilizes a similar mechanism, but with autologous TL-loaded yeast cell wall particles; this eliminates the need for dendritic cell (DC) collection and ex-vivo loading and reduces production costs and time. The TLPO vaccine was compared to TLPLDC in an embedded bridging portion of the trial. Here, we examine 36-month outcomes of the ongoing randomized, double-blind phase 2 trial in patients (pts) with resected stage III/IV melanoma.MethodsPts were randomized 2:1 to receive TLPO or TLPLDC as a continuation of a previously established clinical trial comparing TLPLDC versus placebo. The TLPLDC group was analyzed separately based on use (or not) of G-CSF for collection of DC. Safety was measured by the Common Terminology Criteria for Adverse Events (CTCAE). Kaplan-Meier and log-rank analysis was used to compare 36-month disease-free survival (DFS) and overall survival (OS) in the intention-to-treat (ITT) main arms as well as pre-specified subgroups.ResultsA total of 187 pts were randomized with 41, 47, 56, and 43 pts enrolled in the placebo, TLPLDC without G-CSF (TLPLDC), TLPLDC with G-CSF (TLPLDC+G), and TLPO arm, respectively. Pts randomized to the TLPO arm were more likely to have stage IV melanoma (22.0% for placebo, 20.4% for TLPLDC and TLPLDC+G, and 44.2% for TLPO; p = 0.002) and to receive prior immunotherapy (36.6% for placebo, 39.8% for both TLPLDC and TLPLDC+G, and 83.7% for TLPO; p < 0.001). Grade 3+ adverse events were not significantly different between arms. In the ITT analysis, 36-month DFS was 30.0% for placebo, 55.8% for TLPLDC, 24.4% for TLPLDC+G, and 64.0% for TLPO (p < 0.001). OS at 36 months was 70.9% for placebo, 94.2% for TLPLDC, 69.8%% for TLPLDC+G, and 94.8% for TLPO (p = 0.011) (figure 1).Abstract 542 Figure 1Kaplan-Meier curves demonstrating DFS (A) and OS (B) between Placebo (n=41), TLPLDC (n=47), TLPLDC+G (n=56), and TLPO (n=43)ConclusionsThe TLPO and TLPLDC (without G-CSF) vaccines improved 36-month DFS and OS in this randomized phase 2 trial. The efficacy of the TLPO and TLPLDC vaccines will be confirmed in a phase III trial in resected Stage III/IV melanoma pts.Trial RegistrationNIH, clinicaltrials.gov, NCT02301611ReferencesO’Shea AE, Chick RC, Clifton GT, et al. The effect of pretreatment with G-CSF prior to dendritic cell collection during the phase IIb trial of an autologous DC-based vaccine for advanced, resectable melanoma. Presented at: Society for Immunotherapy of Cancer 35th Anniversary Annual Meeting & Preconference Programs (SITC 2020); November 11–14, 2020. Abstract 310. J Immunother Cancer. 2020;8(Suppl 3):A656–A959.Ethics ApprovalThe clinical trial protocol was approved by the Western Institutional Review Board (2014–1932). All participants provided informed consent prior to enrollment in the trial.

Immunotherapy has revolutionized the treatment of melanoma, yet survival remains poor for patients with metastatic disease. The autologous tumor lysate, particle-loaded, dendritic cell (TLPLDC) vaccine has been shown to be safe adjuvant therapy for patients with resected stage III/IV melanoma who complete the primary vaccine series. Here, we describe an open-label trial of patients with metastatic melanoma treated with TLPLDC vaccine in addition to standard of care (SoC) therapies. The TLPLDC vaccine is created by loading autologous tumor lysate into yeast cell wall particles, which are phagocytosed by autologous dendritic cells ex vivo. Patients who recurred while enrolled in a phase IIb trial of adjuvant TLPLDC vaccine (crossover cohort) and patients with measurable metastatic melanoma cohort were offered TLPLDC vaccine along with SoC therapies. Tumor response was measured by RECIST 1.1 criteria. Overall survival (OS) and progression-free survival (PFS) were estimated by intention-to-treat analysis. Fifty-four patients were enrolled (28 in crossover cohort; 26 in metastatic melanoma cohort). The vaccine was well-tolerated with no grade ≥3 adverse events when given with SoC therapies to include checkpoint inhibitors, BRAF/MEK inhibitors, tyrosine kinase inhibitors, intralesional therapy and/or radiation. In the crossover arm, OS was 76.5% and PFS was 57.1% (median follow-up of 13.9 months). In the metastatic melanoma arm, OS was 85.7% and PFS was 52.2% (median follow-up 8.5 months). The TLPLDC vaccine is well-tolerated and safe in combination with SoC therapies. Future trials will determine the efficacy of TLPLDC in combination with SoC therapies in metastatic melanoma.

BACKGROUND Secondary overtriage is a problematic phenomenon because it creates unnecessary expense and potentially results in the mismanagement of healthcare resources. The rates of secondary overtriage among patients with complicated mild traumatic brain injury (cmTBI) are unknown. OBJECTIVE To determine the rate of secondary overtriage among patients with cmTBI using the institutional trauma registry. METHODS An observational study using retrospective analysis of 1447 hospitalizations including all consecutive patients with cmTBI between 2004 and 2013. Data on age, sex, race/ethnicity, insurance status, GCS, Injury Severity Score (ISS), Trauma Injury Severity Score, transfer mode, overall length of stay (LOS), LOS within intensive care unit, and total charges were collected and analyzed. RESULTS Overall, the rate of secondary overtriage among patients with cmTBI was 17.2%. These patients tended to be younger (median: 41 vs 60.5 yr; P

Military experience has shown low-titer O whole blood (LTOWB) to be safe and beneficial in the resuscitation of hemorrhaging trauma patients. However, few civilian centers use LTOWB for trauma resuscitation. We evaluated the early experience and safety of a LTOWB program at a level 1 civilian trauma center.We retrospectively reviewed our trauma registry from January 2018 to June 2020 for patients admitted in shock (defined as ≥1 of the following: heart rate,120 beats per minute; systolic blood pressure,90 mm Hg; or shock index,0.9) who received blood products within 24 hours. Patients were grouped by resuscitation provided: LTOWB (group 1), component therapy (CT; group 2), and LTOWB-CT (group 3). Safety, outcomes, and variables associated with LTOWB transfusion and mortality were analyzed.216 patients were included: 34 in Group 1, 95 in Group 2, and 87 in Group 3. Patientsreceiving LTOWB were more commonly male (p0.001) and had a penetrating injury (p=0.005). Groups 1 and 3 had higher median ISS scores compared to Group 2 (19 and 20 vs 17; p=0.01). Group 3 received more median units of blood product in the first 4h (p0.001) and in the first 24h (p0.001). There was no difference between groups in 24h mortality or transfusion-related complications (all p0.05). Arrival ED SBP was associated with LTOWB transfusion (odds ratio [OR] 0.98, 95% confidence interval [CI] 0.95-1.00, p=0.03). ED lactate was independently associated with 24h mortality. (OR 1.27, CI 1.02-1.58, p=0.03). LTOWB transfusion was not associated with mortality (p=0.49). Abstract.Severely injured patients received LTOWB-CT and more overall product units but had similar 24 h mortality when compared with the LTOWB or CT groups. No increase in transfusion-related complications was seen after LTOWB transfusion. Low-titer O whole blood should be strongly considered in the resuscitation of trauma patients at civilian centers.Retrospective, therapeutic, level IV.

Background Checkpoint inhibitors (CPI) in combination with cell‐based vaccines may produce synergistic antitumor immunity. The primary analysis of the randomized and blinded phase IIb trial in resected stage III/IV melanoma demonstrated TLPLDC is safe and improved 24‐month disease‐free survival (DFS) in the per treatment (PT) analysis. Here, we examine efficacy within pre‐specified and exploratory subgroups. Methods Stage III/IV patients rendered disease‐free by surgery were randomized 2:1 to TLPLDC vaccine versus placebo. The pre‐specified PT analysis included only patients completing the primary vaccine/placebo series at 6 months. Kaplan–Meier analysis was used to compare 24‐month DFS among subgroups. Results There were no clinicopathologic differences between subgroups except stage IV patients were more likely to receive CPI. In stage IV patients, 24‐month DFS was 43% for vaccine versus 0% for placebo (p = 0.098) in the ITT analysis and 73% versus 0% (p = 0.002) in the PT analysis. There was no significant difference in 24‐month DFS when stratified by use of immunotherapy or CPI. For patients with resected recurrent disease, 24‐month DFS was 88.9% versus 33.3% (p = 0.013) in the PT analysis. All benefit from vaccination was in the PT analysis; no benefit was found in patients receiving up to three doses. Conclusion The TLPLDC vaccine improved DFS in patients completing the primary vaccine series, particularly in the resected stage IV patients. The efficacy of the TLPLDC vaccine will be confirmed in a phase III study evaluating adjuvant TLPLDC + CPI versus Placebo + CPI in resected stage IV melanoma patients., TLPLDC is an autologous tumor lysate vaccine made with autologous dendritic cells to prevent recurrence in patients with high‐risk resected melanoma. In this analysis, the vaccine was found to have the most benefit in stage IV resected patients and may have a synergistic effect in combination with checkpoint inhibitors. ​

OBJECTIVE To describe the feasibility, efficacy, and learner perception of the flipped classroom model for teaching conferences within surgical training programs. DESIGN For the flipped classroom conferences, video lectures were prepared by a faculty member, and sent to all attendees at least 2 days prior to lecture. The conference time was then spent going over cases and questions, rather than traditional lecture. We conducted a qualitative survey to assess learner's perceptions and pre-lecture quizzes to assess trainee preparedness. SETTING The comparison of pre-conference quizzes between flipped classroom and traditional models was carried out at Brooke Army Medical Center (BAMC) in San Antonio, TX, a tertiary care facility with a general surgery residency program. The survey was conducted at BAMC and within the Complex General Surgical Oncology fellowship program at University of Texas MD Anderson Cancer Center, where a flipped classroom model was similarly employed. PARTICIPANTS Surgical residents BAMC participated in pre-lecture quizzes. BAMC residents and MD Anderson fellows were invited to complete the online survey. RESULTS Lecture videos did not increase mean preparation time (1.53 vs. 1.46 hours without vs. with video, p = 0.858), but did increase mean quiz scores from 67% to 80% (p = 0.031) with 32/35 learners utilizing videos. Videos increased the proportion of learners who self-reported preparing at all from 42% to 95% (p = 0.28), and preparing for at least one hour for conference from 23% to 49% (p = 0.014). Of survey respondents, 90% said videos were very helpful, 90% would use them weekly if available, and 90% prefer this format to traditional lecture. CONCLUSIONS Utilization of a flipped classroom method was well received and preferred by surgical trainees, and it increased performance on pre-conference quizzes without increasing preparation time. Although creation of video lectures is work-intensive for lecturers, these results suggest it is more effective for learner preparation. These results could be generalizable to surgical residents nationwide as technology utilization increases in surgical education.

Background We have completed a prospective, randomized, multi-center, double-blind, placebo-controlled phase IIb trial of the tumor lysate, particle loaded, dendritic cell (TLPLDC) vaccine given to prevent recurrences in patients with resected stage III/IV melanoma. During the trial, granulocyte colony stimulating factor (G-CSF) was administered to some patients to mobilize dendritic cells (DCs) precursors prior to harvest, allowing for similar DC yield with reduced blood draws. This study examines the impact of DC collection methods on vaccine effectiveness. Methods TLPLDC is produced by loading tumor lysate into pre-prepared yeast cell wall particles (YCWPs) and exposing them to autologous DCs. DC precursors were isolated either by collection of 50–70 mL of blood following pre-administration of 300µg of G-CSF 24–48 hrs prior, or collection of 120 mL of peripheral blood without G-CSF pretreatment based on patient and provider preference. Patients were randomized 2:1 to receive TLPLDC or placebo (DCs exposed to empty YCWPs). 1–1.5 × 106 cells/dose were injected intradermally at 0, 1, 2, 6, 12, and 18 months. Differences in disease free survival (DFS) and overall survival (OS) were analyzed by log rank. Results Of 144 patients randomized, 103 received TLPLDC and 41 received placebo. Within the TLPLDC group, 57 received pretreatment with G-CSF (TLPLDC+G-CSF) and 46 did not (TLPLDC–G-CSF). There were no significant clinicopathologic or treatment differences between the three treatment arms. 36-month DFS was significantly better in TLPLDC–G-CSF vs. TLPLDC+G-CSF or placebo (51.8% vs. 23.4% and 27.1% respectively, p=0.027) (figure 1). TLPLDC–G-CSF had correspondingly improved OS (92.9% vs. 62.8% and 72.3% respectively, p=0.022) (figure 2). Subgroup analysis revealed TLPLDC–G-CSF had increased DFS over TLPLDC+G-CSF or placebo in Stage IV (68.6% vs. 18.8% and 0.0% respectively, p=0.058). Similarly, the DFS survival benefit of TLPLDC–G-CSF was enhanced in patients who received prior immunotherapy (IO) (61.9% vs. 11.5% and 35.7% respectively, p=0.007) or checkpoint inhibitors (CPI) (48.5% vs. 10.6% and 37.5% respectively, p=0.039). Conclusions TLPLDC vaccine created without G-CSF pretreatment significantly improved 36-month DFS and OS compared to TLPLDC+G-CSF or placebo in stage III/IV (resected) melanoma patients. On further subgroup analysis, the increases in OS and DFS were more profound in patients who received additional immune therapies to include CPI. Ongoing evaluation will determine if G-CSF mobilization leads to collection of phenotypically different DCs. Based on these results, we are planning a phase III trial of TLPLDC–G-CSF + CPI vs. placebo + CPI in advanced melanoma post-resection. Trial Registration ClinicalTrials. gov Identifier: NCT02301611 Ethics Approval This study was reviewed and approved by the IRB or Independent Ethics Committee (IEC) of each participating center prior to study initiation.

Background The autologous tumor lysate, particle-loaded, dendritic cell (TLPLDC) vaccine is safe and effective in improving 24 and 36-month disease-free survival (DFS) in patients (pts) with resected stage III/IV melanoma who completed the primary vaccine series. The tumor lysate, particle only (TLPO) vaccine has been developed to accelerate production by omitting DC isolation and ex vivo loading in favor of in vivo phagocytosis of the TL-loaded particles. We are currently conducting a randomized and double-blind trial of the TLPO vs TLPLDC to improve DFS and overall survival (OS) in patients with resected late stage melanoma. Methods Patients with stage III/IV melanoma who were clinically disease-free after standard of care therapies were randomized to receive TLPO vs TLPLDC (2:1) as a continuation of the phase IIb trial comparing TLPLDC vs placebo (2:1). For the TLPLDC vaccine, autologous TL was loaded into yeast cell wall particles (YCWP) which were then phagocytized by isolated autologous DC ex vivo. For the placebo DC were loaded with empty YCWP. For TLPO, the autologous TL-loaded YCWP were coated with a chemoattractant and injected intradermally for in vivo phagocytosis. Some patients in the TLPLDC arm received G-CSF prior to DC harvest to minimize blood draw (60 mL instead of 120 mL without G-CSF). For all arms, six vaccine/placebo doses were administered intradermally at 0, 1, 2, 6, 12, and 18 mos. Data was analyzed by an intention-to-treat (ITT) analysis for DFS and OS by the Kaplan-Meier method and compared by log-rank test. Results 63 pts were randomized to TLPO (n=43) vs TLPLDC (n=20). The TLPO cohort contained more females and received less chemotherapy (0% vs 10%), but otherwise were comparable. There were no differences in DFS (p=0.948) or OS (p=0.779) between the two vaccines (figures 1&2). Comparing the TLPO pts to all other pts in the phase IIb trial [TLPLDC+G-CSF (n=57), TLPLDC-G-CSF (n=46), and placebo (n=41)] the TLPO arm had improved DFS compared to placebo (p=0.019) and TLPLDC+G-CSF (p=0.001), but roughly equivalent to the TLPLDC-G-CSF arm (p=0.276) (figure 3). A similar trend was seen in OS analysis, though differences were not statistically significant (figure 4). Conclusions TLPO and TLPLDC vaccines (without the use of G-CSF) improve DFS in patients with resected stage III/IV melanoma compared to placebo. The TLPO vaccine may offer advantages via reduced cost and vaccine production time. TLPO should be closely considered for further clinical trials. Trial Registration NCT02301611: Phase IIB TL + YWCP + DC in MelanomaTLPLDC IND#16101TLPO IND#17274 Ethics Approval This study was approved by WIRB; protocol #20141932

Background The tumor lysate, particle-loaded, dendritic cell (TLPLDC) vaccine is created ex vivo by loading autologous dendritic cells (DC) with yeast cell wall particles (YCWP) containing autologous tumor lysate, thus delivering tumor antigens to the DC cytoplasm via phagocytosis. TLPLDC then activates a robust T cell response against the unique antigens for each patient. The primary analysis of the prospective, randomized, multi-center, double-blind, placebo-controlled phase IIb trial in patients with resected stage III/IV melanoma showed TLPLDC improved 24-month disease-free survival (DFS) in the per-treatment (PT) analysis (patients completing the 6-month primary vaccine series). Here, we examine the secondary endpoint of 36-month DFS and overall survival (OS). Methods Patients with resected stage III/IV melanoma were randomized 2:1 to TLPLDC vaccine or placebo (autologous DC loaded with empty YCWP). Treatments were given at 0, 1, 2, 6, 12 and 18 months. The protocol was amended to include patients receiving concurrent checkpoint inhibitors (CPIs) to follow changes in standard of care. The co-primary endpoints were 24-month DFS by intention-to-treat (IT) analysis and per-treatment (PT) analysis, with secondary endpoints including 36-month DFS and OS by ITT and PT analysis, pre-specified analysis by stage, and safety as measured by CTCAE v4.03. Results Overall, 103 patients received TLPLDC and 41 placebo. In PT analysis, 65 patients received TLPLDC and 32 placebo. Total adverse events (AEs), grade 3+ AEs, and serious AEs (SAEs) were similar in placebo vs TLPLDC groups, with one related SAE per treatment arm. By ITT analysis, 36-month OS was 76.2% for TLPLDC vs 70.3% for placebo (HR 0.72, p=0.437) and 36-month DFS was 35.6% vs 27.1% (HR 0.95, p=0.841). By PT analysis, 36-month DFS was improved with TLPLDC (57.5% vs 35.0%; HR 0.50, p=0.025, figure 1). This effect was even more dramatic in resected stage IV patients (36-month DFS: 60.9% vs 0%; HR 0.12, p=0.001, figure 2). Conclusions This phase IIb trial again demonstrates the safety of the TLPLDC vaccine, and an improved 36-month DFS in patients with resected stage III/IV melanoma who complete the primary vaccine series, particularly in the stage IV subgroup. Next, a phase III trial will evaluate the efficacy of TLPLDC vaccine as adjuvant treatment for resected stage IV melanoma, with patients randomized to receive standard of care PD-1 inhibitors + TLPLDC versus PD-1 inhibitors + placebo. Trial Registration This is a phase IIb clinical trial registered under NCT02301611 Ethics Approval This study was approved by Western IRB, protocol 20141932.

Lymphadenectomy (LND) is recommended following surgical resection of ≥ T1b gallbladder cancer (GBC). However, frequency and stage-specific survival benefits of LND remain unclear.The National Cancer Database (NCDB; 2006-15) was queried for resected pathologic stage I-III GBC. LND performance, predictors of receiving LND, and LND association with overall survival (OS) were assessed.Of 2302 total patients, 1343 (58.3%) underwent LND. Patients who underwent LND were younger and more frequently had private health insurance, a negative surgical margin, higher pathologic T stage, and received adjuvant chemotherapy (all p0.001). LND rates were highest at academic centers (70.1%) relative to all other facility types (p0.001). LND was independently associated with improved OS [hazard ratio (HR) 0.52, 95% confidence interval (CI) 0.44-0.61]. LND was associated with improved OS for pT1b, pT2, and pT3 patients (all p0.05) on univariate analysis. LND was independently associated with improved OS in pT2 (HR 0.44, CI 0.35-0.56) and pT3 (HR 0.54, CI 0.43-0.69) patients.LND is associated with a 48% reduction in risk of death in patients with resectable non-metastatic GBC, with greatest impact in pT2-3 patients. Patients without LND have similar OS to patients with node-positive disease, highlighting the importance of LND. Underutilization of LND likely results in undertreatment of patients with undiagnosed nodal disease, which may contribute to unfavorable oncologic outcomes.

Routine lymphadenectomy (LND) for resectable hepatocellular carcinoma (HCC) remains controversial. We evaluated national LND trends to identify pre-operative factors associated with node-positive disease to determine which patients might benefit from LND.We identified HCC patients in the National Cancer Database (NCDB) treated with surgical resection between 2004 and 2015. Demographic, operative, pathologic, and survival data were compared. Multivariable regression was performed to determine preoperative predictors of pathologic nodal disease.Of 8095 total resected patients, 1442 (17.8%) underwent hepatectomy with LND. Patients who received LND had higher preoperative clinical T (T3-T4: 20.0% vs 12.1%, p 0.001) and N (N1: 3.3% vs 0.6%, p 0.001) stages. The strongest independent predictor of pathologic nodal disease was clinical N stage (OR 106.54, CI 44.10-257.42). Survival was highest in patients whose surgeons omitted LND or were found with LND to be node-negative on final pathology (p 0.001). Clinical node positivity had high negative predictive value (97.9%) but moderate positive predictive value (56.3%) in estimating pathologic nodal status.Defining preoperative clinical nodal status is imperative in HCC patients. Clinical node positivity was the strongest predictor of pathologic nodal disease and its associated worse prognosis. LND can be considered selectively in clinically node-positive patients.

No approved medical therapies prevent progression of low-grade prostate cancer. Rapamycin inhibits cell proliferation and augments immune responses, producing an antitumor effect. Encapsulated rapamycin (eRapa) incorporates rapamycin into a pH-sensitive polymer, ensuring consistent dosing. Here, we present results from a phase I trial evaluating the safety and tolerability of eRapa in patients with prostate cancer. Patients with Gleason ≤7 (3+4) disease (low and intermediate risk) under active surveillance were enrolled in a 3+3 study with three eRapa dosing cohorts (cohort 1, 0.5 mg/week; cohort 2, 1 mg/week; and cohort 3, 0.5 mg/day). Patients were treated for 3 months and followed for an additional 3 months to assess safety, pharmacokinetics, quality of life (QoL), immune response, and disease progression. Fourteen patients (cohort 1, n = 3; cohort 2, n = 3; and cohort 3, n = 8) were enrolled. In cohort 3, one dose-limiting toxicity (DLT; neutropenia) and two non-DLT grade 1–2 adverse events (AE) occurred that resulted in patient withdrawal. All AEs in cohorts 1 and 2 were grade 1. Peak serum rapamycin concentration was 7.1 ng/mL after a 1 mg dose. Stable trough levels (∼2 ng/mL) developed after 48–72 hours. Daily dosing mildly worsened QoL, although QoL recovered after treatment cessation in all categories, except fatigue. Weekly dosing increased naïve T-cell populations. Daily dosing increased central memory cell populations and exhaustion markers. No disease progression was observed. In conclusion, treatment with eRapa was safe and well-tolerated. Daily dosing produced higher frequencies of lower grade toxicities and transient worsening of QoL, while weekly dosing impacted immune response. Future studies will verify clinical benefit and long-term tolerability. Prevention Relevance: There is an unmet medical need for a well-tolerated treatment capable of delaying progression of newly diagnosed low-grade prostate cancer. This treatment would potentially obviate the need for future surgical intervention and improve the perception of active surveillance as a more acceptable option among this patient population.

Background The COVID-19 pandemic presents a unique challenge to surgical residency programs. Due to the restrictions recommended by the Centers for Disease Control and Prevention and other organizations, the educational landscape for surgical residents is rapidly changing. In addition, the time course of these changes is undefined. Methods We attempt to define the scope of the problem of maintaining surgical resident education while maintaining the safety of residents, educators, and patients. Within the basic framework of limiting in-person gatherings, postponing or canceling elective operations in hospitals, and limiting rotations between sites, we propose innovative solutions to maintain rigorous education. Results We propose several innovative solutions including the flipped classroom model, online practice questions, teleconferencing in place of in-person lectures, involving residents in telemedicine clinics, procedural simulation, and the facilitated use of surgical videos. Although there is no substitute for hands-on learning through operative experience and direct patient care, these may be ways to mitigate the loss of learning exposure during this time. Conclusions These innovative solutions utilizing technology may help to bridge the educational gap for surgical residents during this unprecedented circumstance. The support of national organizations may be beneficial in maintaining rigorous surgical education.

Adjuvant chemotherapy (AC) is recommended following surgical resection of gallbladder cancer regardless of stage. However, stage-specific benefits of AC in gallbladder cancer are unclear.Patients with resected pathologic stage I-III gallbladder cancer were identified using the 2006-2015 National Cancer Database. Utilization trends, predictors of use, and impact of AC on overall survival (OS) were determined.A total of 5656 patients were included. Use of AC increased from 9.9% in 2006 to 24.2% in 2015 (OR 2.91; 95% CI 2.06-4.09; p 0.001). However, only 17.5% of patients overall and only 32.4% of node-positive (stage IIIb) patients received AC. Patients receiving AC were younger and had fewer comorbidities, shorter hospitalizations, more advanced disease, and more margin-positive resections (all p 0.01). Higher pathologic T stage and positive nodal status represented the greatest independent predictors of receipt of AC. While AC demonstrated no OS advantage for stage I patients (p = 0.83), AC was associated with improved OS among stage II patients (p = 0.003), though this impact was not independently associated with improved OS on multivariable analysis. AC was independently associated with improved OS among stage IIIb patients, with a 30% reduction in risk of death (HR 0.70; 95% CI 0.58-0.83; p 0.001). Younger age, fewer comorbidities, and shorter hospitalization all predicted receipt of AC among stage IIIb patients (all p 0.05).Systemic therapy remains underprescribed, in particular among patients that would seem to benefit most. Adjuvant chemotherapy likely improves survival in node-positive gallbladder cancer, but its utility in the treatment of node-negative disease has not been demonstrated.

Variability exists in opioid prescribing practices among surgeons, frequently resulting in the prescription of excessive opioids. This study evaluated the ability of a single educational intervention targeted toward general surgery residents to reduce the quantity of postoperative opioids prescribed.This retrospective cohort study evaluated opioid prescribing practices 12 mo prior to and 6 mo following a 30-min lecture for general surgery residents that discussed prescribing guidelines and multimodal analgesia. Opioid volumes (normalized to oral morphine equivalents, OME), opioid type, nonopioid pain medications, and refills requested were analyzed for opioid-naïve adult patients undergoing excisional breast biopsy (EB), mastectomy (M), laparoscopic appendectomy (LA), laparoscopic cholecystectomy (LC), open umbilical hernia repair (OUHR), open inguinal hernia repair (OIHR), or laparoscopic inguinal hernia repair (LIHR).695 and 376 patients preintervention and postintervention were included, respectively. Median OME prescribed decreased for EB (150 mg to 75 mg, P 0.001), M (225 mg to 150 mg, P = 0.85), LA (150 mg to 94 mg, P 0.001), LC (150 mg to 82 mg, P 0.001), OUHR (150 mg to 103 mg, P 0.001), OIHR (175 mg to 100 mg, P = 0.001), and LIHR (200 mg to 113 mg, P 0.001). Fewer patients received opioids alone and more patients received an opioid with two nonopioid adjuncts (P 0.001). More patients received oxycodone as fewer received acetaminophen-containing opioid combinations (P 0.001). Patients requiring refills decreased (11.9% to 7.2%) (P = 0.014).Following this targeted intervention, patients were discharged with fewer OME and more nonopioid analgesics, even as refill requests decreased. Educating residents on opioid prescription guidelines and multimodal therapy is effective and should be part of the annual didactic curriculum.

9548 Background: A randomized, double-blind, placebo-controlled phase IIb trial of the tumor lysate, particle loaded, dendritic cell (TLPLDC) vaccine was conducted to prevent recurrence in patients (pts) with resected stage III/IV melanoma. Two methods for dendritic cell (DC) harvest were used for vaccine production, including no pretreatment or pretreatment with granulocyte-colony stimulating factor (G-CSF) in an attempt to reduce blood draw volumes. This analysis investigates differences in clinical outcomes and RNA gene expression between these DC harvest methods for TLPLDC vaccine creation. Methods: The TLPLDC vaccine is created by loading autologous tumor lysate into yeast cell wall particles (YCWPs) and exposing them to phagocytosis by DCs. By investigator/pt choice, pts had 120mL of blood drawn for DC harvest, or pts received 300μg of G-CSF for pre-DC mobilization and a 50-70 mL blood draw 24-48 hours later. Total vaccine production time was 72 hrs. Pts were randomized 2:1 to receive TLPLDC or placebo (DCs exposed to empty YCWPs). 1-1.5 x10^6 cells/dose were injected intradermally at 0, 1, 2, 6, 12, and 18 months. Differences in disease free survival (DFS) and overall survival (OS) were evaluated by Kaplan Meier analysis between pts who did not receive pretreatment (TLPLDC), pts who did receive pretreatment with G-CSF (TLPLDC+G), and pts receiving placebo. RNA-seq analysis was performed on the total RNA of pts’ prepared TLPLDC vaccines to assess gene expression. Relative RNA expression (RRE) was compared between TLPLDC and TLPLDC+G. Results: As previously reported, 144 pts were randomized: 103 received TLPLDC (46 TLPLDC, 57 TLPLDC+G) and 41 received placebo. There were no significant clinicopathologic or treatment differences between the three treatment arms. Survival was significantly improved in TLPLDC compared to TLPLDC+G or placebo, including 36-month OS (92.9% vs 62.8% vs 72.3% respectively, p = 0.022) and DFS (51.8% vs 23.4% vs 27.1%, p = 0.027). When compared to TLPLDC+G (n = 3) vaccine, RNA-seq from TLPLDC vaccine (n = 3) showed upregulation of genes associated with DC maturation, including HLA-DMB (RRE: 3.60), IFIT1 (3.38), CD27 (3.26), IFI44L (3.24), MX1 (2.96), HLA-DQA1 (2.67), HLA-DRA (2.40), CD49D (2.34) and CD74 (2.09), while downregulated genes were associated with DC suppression or immaturity including SERPINA1 (RRE:7.8), TLR2 (6.65), CCR1 (5.11), IL10 (4.19), CD93 (3.84) and CD14 (3.25). Conclusions: Pts receiving TLPLDC vaccine had significantly improved OS and DFS, while outcomes remained similar between those who received TLPLDC+G vs placebo. Pts who did not receive G-CSF had higher expression of genes linked to DC maturation and antigen processing and presentation, likely explaining the improvement in clinical efficacy. A phase III trial to further assess the TLPLDC vaccine to prevent recurrence is planned. Clinical trial information: NCT02301611.

Background: The treatment of melanoma has changed drastically with the advent of immunotherapy, particularly checkpoint inhibition (CPI). Unfortunately, only 50-60% of tumors respond to current immunotherapy. The autologous tumor lysate, particle loaded, dendritic cell (TLPLDC) vaccine utilizes the whole antigenic panel of the patient's tumor to stimulate T-cells and may work synergistically with other immunotherapies. We have previously demonstrated both safety and efficacy of TLPLDC vaccine as adjuvant therapy for patients (pts) with resected stage III or IV melanoma who complete the primary vaccine series. Here, we describe results in pts with metastatic melanoma treated with the TLPLDC vaccine together with other approved therapies. Methods: The TLPLDC vaccine is created by loading autologous tumor lysate into yeast cell wall particles which are then phagocytosed by autologous dendritic cells ex-vivo. Pts who recurred while enrolled in a randomized phase IIb trial of adjuvant TLPLDC vaccine (crossover arm) and pts with metastatic melanoma with measurable disease (MM arm) were offered TLPLDC vaccine in an open-label fashion in addition to other approved therapies as determined by their treating physician. The vaccine is given via intradermal injection monthly x4 followed by boosters at six and nine months. Tumor response is measured by RECIST 1.1 criteria. Results: To date, 53 pts have been enrolled (28 in the crossover arm and 25 in the MM arm). Within the crossover arm, 18 pts had received TLPLDC as part of the phase IIb trial, 8 were from the placebo group, and 2 patients withdrew prior to vaccination. Within the MM arm, 2 were excluded for no evidence of disease at time of vaccination and 1 withdrew. The vaccine was well tolerated, with 24% of patients experiencing a treatment-related adverse event (AE), with no grade ≥3 AE. Concurrent therapies were varied in the crossover arm, but 36% received CPI, compared with 68% in the MM arm. Of those receiving CPI, 59% had >1 immune-related AE, none of which were grade ≥3. In the crossover arm, 12-month overall survival (OS) was 83.3% in the vaccine-naïve cohort at median follow-up of 6.0 months vs. 94.7% in the re-vaccinated cohort at median follow-up of 9.0 months (p=0.961). In the MM arm, 12-month OS was 61.2% at a median follow-up of 7.7 months. In a pooled analysis of 33 evaluable pts, vaccine-naïve pts (n=21) had a 42.9% non-progression rate compared to a 66.7% non-progression rate in re-vaccinated pts (n=12). Conclusion: Vaccination with the TLPLDC vaccine in combination with approved systemic therapies in MM pts is well tolerated, with acceptable rates of immune-related AE when combined with CPI. Additionally, vaccination, and specifically re-vaccination, may provide clinical benefit particularly if used in combination with other approved therapies. Citation Format: Robert Connor Chick, Annelies T. Hickerson, Guy Travis Clifton, Phillip M. Kemp Bohan, Tommy A. Brown, Jessica L. Cindass, John W. Myers, Timothy J. Vreeland, Doreen O. Jackson, Diane F. Hale, Kaitlin M. Peace, Garth S. Herbert, Xianzhong Yu, Thomas Wagner, George E. Peoples. Safety and efficacy of autologous tumor lysate particle loaded dendritic cell (TLPLDC) vaccination in combination with systemic therapies in patients with metastatic melanoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6536.

Background: Immunotherapy has become a mainstay of adjuvant treatment of advanced melanoma, but recurrence rates remain high. TLPLDC is a personalized vaccine that was shown in a multi-center, double-blind, placebo-controlled phase IIb trial to be safe, well tolerated, and effective for preventing recurrence in patients with resectable stage III or IV melanoma. The trial enrolled patients who had either a new diagnosis of melanoma or recurrent disease. It is hypothesized that the length of disease-free interval (DFI) may be a marker of more indolent disease and therefore a good prognostic factor for vaccine efficacy. In this study, we examined the impact of disease-free interval on response to the vaccination. Methods: Vaccine production and dosing has been described elsewhere. Patients were characterized as having either primary or recurrent disease at the time of enrollment. For recurrent patients, DFI was defined as the length of time between their initial biopsy establishing a diagnosis of melanoma and complete surgical resection. Patients were grouped by DFI into a primary and recurrent group, where the recurrent group had DFI >3 months and the primary group had no prior disease or recurrence with DFI Results: Patients were randomized 2:1 (103 vaccine group, 41 control group) and divided into a recurrent group (n=48) and a primary group (n=96). There was no difference between groups in stage, age, margin status, BRAF mutation, or use of concurrent immunotherapy including checkpoint inhibitors. Patients in the recurrent group had numerically improved 24-month DFS with vaccine vs. placebo (52.6% vs. 23.5%, p=0.214) whereas the primary group had no difference (32.9% vs. 31.8%, p=0.451). Patients in the recurrent group had significantly improved overall survival with vaccine vs. placebo (94.4% vs. 50.5%, p=0.011) whereas the primary group had no difference (83.4% vs. 90.2%, p=0.779). Conclusions: The TLPLDC vaccine improved overall survival in patients with DFI >3 months prior to recurrence. These patients have more indolent disease biology and a less immunosuppressive tumor microenvironment, where monotherapy with a cancer vaccine is thought to be more effective. Further study is required to identify patients at initial presentation who are more likely to benefit from the TLPLDC vaccine. Meanwhile, combination therapy with vaccine and checkpoint inhibitor may be required for those with more aggressive disease biology. Citation Format: Robert Connor Chick, Phillip M. Kemp Bohan, Timothy J. Vreeland, Annelies T. Hickerson, Jessica L. Cindass, Diane F. Hale, Guy Travis Clifton, George E. Peoples. Impact of disease-free interval on recurrence in high-risk melanoma patients in a phase IIb trial of the tumor lysate particle loaded dendritic cell (TLPLDC) vaccine [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6537.

34 Background: At low doses, rapamycin inhibits cell proliferation and angiogenesis while augmenting CD8 T-cell responses, cumulatively producing an antitumor effect. Oral rapamycin is limited by variable bioavailability. Encapsulated rapamycin (eRapa) incorporates submicron rapamycin particles into a pH-sensitive polymer, improving bioavailability and allowing for consistent and lower dosing. Here, we present results of a phase Ib trial evaluating safety and treatment effects of eRapa in patients with low-grade prostate cancer (PCa). Methods: PCa patients with Gleason ≤7 (3+4) under active surveillance were enrolled in a 3+3 study with 3 dosing cohorts (0.5mg weekly, 1mg weekly, and 0.5mg daily) to determine the optimal dosing. Patients were treated for 3 months (m) and followed for 6m. Safety, labs (including PSA), pharmacokinetics, immune response, and quality of life (QOL) were assessed for each cohort. Results: 14 patients were enrolled; 3 in cohort 1, 3 in cohort 2, and 8 in cohort 3. 2 patients withdrew for non-dose limiting toxicity (DLT) (grade 1-2) adverse events (AEs) in cohort 3, leaving 6 evaluable. A single grade 3 DLT (neutropenia) occurred in cohort 3. No AEs > Grade 1 occurred in cohorts 1/2. Peak serum rapamycin concentration ([Rapa]) was 7 ng/mL after a 1 mg dose (2h after administration). Stable trough levels (2 ng/mL) were established after 48 hrs and persisted to 13wks. Central memory CD8 T cells and CD3+/CD56+ NK cells were more prevalent in cohort 3 than other cohorts at 1m (p = 0.027 and p = 0.041) and 3m (p = 0.023 and p = 0.049). There was no significant change in PSA level; no patients clinically progressed on therapy. In cohort 3, there were no differences between baseline and 3m QOL assessments but there was a suggestion of withdrawal effects at 6m. Conclusions: Treatment with low dose eRapa is safe and well-tolerated. The dose of 0.5mg daily produced stable serum [Rapa] through the duration of treatment and resulted in a positive immune impact. Further investigation with low dose and/or intermittent dosing of eRapa as a preventive agent in PCa and other indications will be required to establish clinical benefit. Clinical trial information: NCT03618355.

63 Background: A novel vaccine strategy may prevent recurrence in high-risk melanoma patients (pts). The TLPLDC vaccine uses yeast cell wall particles (YCWP) to load tumor lysate into autologous dendritic cells (DC). In this phase IIb trial of TLPLDC vs. placebo in resected stage III/IV pts, TLPLDC increased 24 month (mo) disease free survival (DFS) in the per treatment (PT) population. Here, we present a 24mo DFS subgroup analysis and estimated overall 36mo DFS. Methods: Disease-free pts were randomized 2:1 to the TLPLDC vaccine vs. unloaded YCWP+DC at 0, 1, 2, 6, 12, and 18mo. The protocol was amended to allow concurrent adjuvant checkpoint inhibitor (CPI) therapy once approved. The pre-specified PT population included only pts completing the primary vaccine/placebo series (PVS) at 6 mo. Kaplan-Meier estimates of DFS were used to compare treatment arms by stage (III or IV) and CPI therapy (yes/no) in the ITT and PT populations. Results: 144 pts were randomized (103 TLPLDC, 41 placebo); 98 pts (66 TLPLDC, 32 placebo) completed the PVS. There were no clinicopathologic differences between treatment groups. There was no difference in 24mo DFS in stage III pts (n = 112), but in stage IV pts (n = 32), the 24mo DFS was 44% vs 0% (TLPLDC vs placebo) (p = 0.41) in ITT and 73.3% vs. 0% (HR 0.14, p = 0.002) in PT. Stage IV pts were more likely to receive CPI than stage III pts (50% vs. 30%, p = 0.003). There was no difference in 24mo DFS for pts who did not receive CPI (n = 102), but in pts who received CPI (n = 42), the 24mo DFS was 49.3% vs. 31.3% (p = 0.71) in ITT and 68.8% vs. 41.7% (HR 0.46, p = 0.28) in PT, showing a trend toward improved DFS in pts who completed the PVS and received CPI (n = 31). Overall, the 36mo estimated DFS was 34.2% vs. 21.6% (p = 0.89) for ITT and 56.9% vs. 27.9% (p = 0.021) for PT. Conclusions: The TLPLDC vaccine improved DFS in patients completing the PVS at 24 and 36 mos, particularly in the resected stage IV subset. The apparent synergistic effect with TLPLDC + CPI will be confirmed in a phase III study evaluating adjuvant TLPLDC + CPI vs. CPI alone in resected stage IV melanoma pts. Clinical trial information: NCT02301611.