Epitope profiling using computational structural modelling demonstrated on coronavirus-binding antibodies

Identifying the epitope of an antibody is a key step in understanding its function and its potential as a therapeutic. Sequence-based clonal clustering can identify antibodies with similar epitope complementarity, however, antibodies from markedly different lineages but with similar structures can engage the same epitope. We describe a novel computational method for epitope profiling based on structural modelling and clustering. Using the method, we demonstrate that sequence dissimilar but functionally similar antibodies can be found across the Coronavirus Antibody Database, with high accuracy (92% of antibodies in multiple-occupancy structural clusters bind to consistent domains). Our approach functionally links antibodies with distinct genetic lineages, species origins, and coronavirus specificities. This indicates greater convergence exists in the immune responses to coronaviruses than is suggested by sequence-based approaches. Our results show that applying structural analytics to large class-specific antibody databases will enable high confidence structure-function relationships to be drawn, yielding new opportunities to identify functional convergence hitherto missed by sequence-only analysis.

Metastatic Prostate Cancer: Treatment Options

<b><i>Background:</i></b> Metastatic prostate cancer (PCa) is associated with considerable diminished overall survival (OS). Standard treatment for metastatic PCa has long been androgen deprivation therapy alone, with patients initially responding to this treatment and then progressing to a castration-resistant phase. <b><i>Summary:</i></b> The advent of novel therapeutic agents has changed this paradigm, with high-level evidence that upfront combination therapy with either docetaxel or new hormonal agents results in improved OS for patients with metastatic hormone-sensitive PCa. In the absence of a comprehensive clinical trial investigating the comparative efficacy and safety of all agents, clinicians are responsible for choosing the most appropriate therapy in close coordination with patients. Furthermore, the same therapeutic agents are also efficient in the castration-resistant phase, leading to the issue of the best therapeutic sequence. Finally, along with systemic therapy and molecular imaging advancements, radiotherapy was investigated in the oligometastatic setting, whether it is to treat the primary tumour or metastases. <b><i>Key Messages:</i></b> In this complex landscape, where providers have multiple effective therapeutic options to treat metastatic PCa patients, priority must be given to determine which treatment combination and sequence is best suited to a particular patient, given his comorbidities and preferences.

Application of FLIC model to predict adverse events onset in neuroendocrine tumors treated with PRRT

To develop predictive models of side effect occurrence in GEPNET treated with PRRT. Metastatic GEPNETs patients treated in our centre with PRRT (177Lu-Oxodotreotide) from 2019 to 2020 were considered. Haematological, liver and renal toxicities were collected and graded according to CTCAE v5. Patients were grouped according with ECOG-PS, number of metastatic sites, previous treatment lines and therapies received before PRRT. A FLIC model with backward selection was used to detect the most relevant predictors. A subsampling approach was implemented to assess variable selection stability and model performance. Sixty-seven patients (31 males, 36 females, mean age 63) treated with PRRT were considered and followed up for 30 weeks from the beginning of the therapy. They were treated with PRRT as third or further lines in 34.3% of cases. All the patients showed at least one G1–G2, meanwhile G3–G5 were rare events. No renal G3–G4 were reported. Line of PRRT administration, age, gender and ECOG-PS were the main predictors of haematological, liver and renal CTCAE. The model performance, expressed by AUC, was > 65% for anaemia, creatinine and eGFR. The application of FLIC model can be useful to improve GEPNET decision-making, allowing clinicians to identify the better therapeutic sequence to avoid PRRT-related adverse events, on the basis of patient characteristics and previous treatment lines.

Sequencing radium 223 and other life-prolonging agents in castration-resistant prostate cancer patients

Background: Radium 223 (RA223) is currently administered as part of a therapeutic sequence with the other life-prolonging agents (LPAs) for metastatic castration-resistant prostate cancer (mCRPC). Patients & methods: We retrospectively reviewed the clinical records of patients who had received at least three LPAs including RA223. Results: Median overall survival (OS) from the start of first-line treatment was 39.8 months, with the patients who completed all six planned courses of RA223 having a longer OS than those who did not (53.2 vs 29.5 months; p < 0.0001). Conclusions: Our study confirms the activity of RA223 regardless of the treatment line in which it is administered and suggests that patient selection plays a central role in maximizing this activity.

Diagnostic capability of ultrasound in peritoneal catheter malfunction compared to videolaparoscopy

Background: The approach to peritoneal catheter malfunction consists usually in a diagnostic and therapeutic sequence of laxative prescription, abdominal radiography, brushing of the catheter, guide-wire manipulation or fluoroscopy and in the end of a videolaparoscopy (VLS) rescue intervention. Ultrasound (US) is able to find out major causes of peritoneal catheter malfunction, however without a clearly defined diagnostic value. The aim of the study was to validate the diagnostic capability of US in catheter malfunction compared to the diagnostic reference of VLS. Methods: US scans of the subcutaneous and intraperitoneal segment of the catheter were performed prior to a VLS intervention in 40 adult patients presenting persistent catheter malfunction within a prospective multicentre study. Laxative prescription and brushing of the catheter lumen were undertaken prior to US scan. US diagnosis was compared to the corresponding at VLS, kappa coefficient calculated and the causes of mismatch analysed. Results: In US, causes of persistent malfunction were catheter dislocation combined with omental wrapping in 21 cases, omental wrapping without dislocation in 11 cases, dislocation only in 4 cases, adherences to non-omental structures in 3 cases and entrapment in the lateral inguinal fossa in 1 case. The US diagnosis corresponded to the respective at VLS in 36 of 40 cases, resulting in a kappa coefficient of 0.89 (95% CI: 0.78–1.00). The discrepancies were due to improper visualization of the catheter between omentum and intestinal loops, resulting in an erroneous US diagnosis of omental wrapping. Conclusions: This study suggests that US might have a pivotal role in the diagnostic approach to peritoneal catheter dysfunction.

Palbociclib Plus Fulvestrant or Everolimus Plus Exemestane for Pretreated Advanced Breast Cancer with Lobular Histotype in ER+/HER2− Patients: A Propensity Score-Matched Analysis of a Multicenter Retrospective Patient Series

Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) in combination with endocrine therapy (ET) show meaningful efficacy and tolerability in patients with metastatic breast cancer (MBC), but the optimal sequence of ET has not been established. It is not clear if patients with lobular breast carcinomas (LBC) derive the same benefits when receiving second line CDK4/6i. This retrospective study compared the efficacy of palbociclib plus fulvestrant (PALBO–FUL) with everolimus plus exemestane (EVE–EXE) as second-line ET for hormone-resistant metastatic LBC. From 2013 to 2018, patients with metastatic LBC positivity for estrogen and/or progesterone receptors and HER2/neu negativity, who had relapsed during adjuvant hormonal therapy or first-line hormonal treatment, were enrolled from six centers in Italy in this retrospective study. A total of 74 out of 376 patients (48 treated with PALBO–FUL and 26 with EVE–EXE) with metastatic LBC were eligible for inclusion. Progression-free survival (PFS) was longer in patients receiving EVE–EXE compared with PALBO–FUL (6.1 vs. 4.5 months, univariate HR 0.58, 95% CI 0.35–0.96; p = 0.025). On the propensity score (PS) analysis, PFS was confirmed to be significantly longer for patients treated with EVE–EXE compared to PALBO–FUL (6.0 vs. 4.6 months, p = 0.04). This retrospective analysis suggests that EVE–EXE is more effective than PALBO–FUL for second line ET of metastatic LBC, allowing us to speculate on the optimal therapeutic sequence.

New potential therapeutic-sequence strategies of TDM1 in the revolutionary era of metastatic HER2-positive breast cancer treatment: A monocentric retrospective experience.

e13014 Background: EMILIA study showed benefits in terms of both progression free survival (PFS) and overall survival (OS) administering Ado-trastuzumab emtansine (T-DM1) vs lapatinib-capecitabine in HER2+ mBC patients (pts) treated at least with a previous trastuzumab-taxane-based therapy. However a paucity of data is available on TDM1 efficacy after dual anti HER2 blockade with pertuzumab and trastuzumab (PT). Instead TH3RESA trial revealed the positive impact on OS of T-DM1 also in heavily pre-treated (at least 2 lines of T, lapatinib and taxanes regimens) pts. We conducted a retrospective analysis reporting innovative findings on the sequence of anti-HER2 treatments and how it could be potentially optimized. Methods: Between June 15, 2014 and January 31, 2020 we identified HER2+ (IHC: 3+ or 2+/FISH amplified) mBC pts treated with T-DM1, either as second-line after progression on dual blockade PT (Cohort PT) or after ≤ 3 anti her2-combined regimens (trastuzumab o lapatinib plus chemotherapy) (Cohort T). 74 pts received T-DM1: Cohort T n = 34 (all females, median age = 52,7), Cohort PT n = 40 (39 females, 1 male, median age = 52,2). Within Cohort T: 64,7 % of pts (n = 22) received T-DM1 after 1 previous anti her2-combined regimen, 20,6 % (n = 7) and 14,7 % (n = 5) in third and fourth lines, respectively. Instead, the whole Cohort PT received second line T-DM1 after pertuzumab/trastuzumab. Results: Median progression- free survival was 10,2 in Cohort T and 3,7 months in Cohort PT. As regards the best response rate, 8,8 % (n = 3/34) and 52,5 % (n = 21/40) of pts reported a progressive disease (PD) into the Cohorts T and PT, respectively: stable disease (SD) 38,2 % (n = 13/34) versus 15 % (n = 6/40); partial response (PR) 23,5 % (n = 8/34) vs 15 % (n = 6/40); complete response (CR) 23,5 % (n = 8/34) vs 12,5 % (n = 5/40). Almost 2/3 (n = 21/34) of Cohort T and half (n = 20/40) of Cohort PT pts had a 3+ IHC status. Conclusions: Our data suggest a lower efficacy of T-DM1 after progression on dual HER2-blockade PT. After all, EMILIA trial did not robustly evaluate the role of T-DM1 in this specific subset of pts. Obviously, larger prospective studies are necessary in order to optimize the best sequence strategy in the treatment of metastatic HER2+ BC, in light of the increasingly innovative anti-HER2 agents.

Systemic Therapy of Neuroendocrine Neoplasia: Single Center Experience from a Cohort of 110 Consecutive Cases

Objective. Neuroendocrine neoplasias (NENs) represent a rare and biologically heterogeneous group of malignancies. Treatment of NEN patients remains challenging due to lack of prospective evidence on the choice of ideal therapeutic sequence and therapeutic efficacy in specific individual scenarios. Methods. Clinical data on 110 consecutive patients suffering from NEN treated at a single German university center were analyzed, therapeutic regimens applied were assessed, and the outcome was evaluated. Results. Histological grading, Ki67 proliferation index, functional activity, and presence of metastases were identified as prognostic markers. 10-year overall survival rates were 92%, 44%, and 0% for G1, G2, and G3 tumors, and 60%, 39%, 69%, 53%, and 0% for Ki67 <2%, 3–5%, 6–20%, 21–49%, and >50%, respectively. Peptide receptor radionuclide therapy (PRRT) and cytostatic chemotherapy were the second most common options, with PRRT being used more frequently in NET G1 and G2 and chemotherapy in NEC G3. Combination chemotherapy with etoposide plus cisplatin or carboplatin showed disease control rates (DCRs) of overall 74%, with a short median progression-free survival (PFS) of 7 or 5 months, respectively. DCR and PFS for PRRT were 89% and 22 months when administered as monotherapy, versus 100% and 27 months upon combination with somatostatin analog (SSA) therapy. Of note, PRRT also achieved disease control as best response in 5/5 (100%) selected cases of NEC G3. Conclusion. Further prospective studies are warranted to help stratify available options for therapeutic intervention in NEN patients.

P58 IMPACT OF SYSTEMATIC ENTERAL NUTRITION IN OESOPHAGEAL OR OESOGASTRIC JUNCTION (OG) CANCERS INVOLVED IN A CURATIVE STRATEGY

Aim In the absence of severe dysphagia or major weight loss, most patients treated for OG cancer do not have enteral nutrition (EN) instituted before neoadjuvant treatment. The aim of this work was to compare the impact of a systematic NE (NES) or on demand (NED) on the course of the therapeutic sequence, the post-operative follow-up: post-operative complications of grade Clavien-Dindo> II and Complication Comprehensive Index (CCI); and oncologic results (median follow-up: 36 months). Background & Methods Among 682 patients with OG cancer operated between 2007 and 2015, 313 patients with <20% weight loss and no severe dysphagia (Atkinson <IV) were included. Control group with NES (n = 140) and group with NED (n = 173) were compared with propensity score adjustment. Results In the NES group, the tumor stage was more advanced (clinical stage III: 78.6% vs 61.4% p = 0.001) and the more frequent undernutrition (28.6% vs 14.6% p = 0.002). After adjustment, there was no significant difference between the two groups regarding the risk of severe complications (25.7% vs 24.9% p = 0.682), the median CCI (20.9 vs 20.9, p = 0.08) and 90-day mortality (4.3% vs. 5.2% p = 0.706). In case of perioperative chemotherapy, the rate of patients benefiting from the complete therapeutic sequence was higher in the NES group (80.4% vs 62.2% p = 0.0192 ie OR = 2.5). Overall survival was similar between the 2 groups (p = 0.509). Conclusion In OG cancers, systematic NE does not modify the operative and oncological follow-ups with respect to an on-demand NE, but more frequently makes it possible to achive the therapeutic sequence in the case of perioperative chemotherapy.