Conventional Cytotoxic Therapy Research Articles

Monocytic Differentiation in Acute Myeloid Leukemia Cells: Diagnostic Criteria, Biological Heterogeneity, Mitochondrial Metabolism, Resistance to and Induction by Targeted Therapies.

We review the importance of monocytic differentiation and differentiation induction in non-APL (acute promyelocytic leukemia) variants of acute myeloid leukemia (AML), a malignancy characterized by proliferation of immature myeloid cells. Even though the cellular differentiation block is a fundamental characteristic, the AML cells can show limited signs of differentiation. According to the French-American-British (FAB-M4/M5 subset) and the World Health Organization (WHO) 2016 classifications, monocytic differentiation is characterized by morphological signs and the expression of specific molecular markers involved in cellular communication and adhesion. Furthermore, monocytic FAB-M4/M5 patients are heterogeneous with regards to cytogenetic and molecular genetic abnormalities, and monocytic differentiation does not have any major prognostic impact for these patients when receiving conventional intensive cytotoxic therapy. In contrast, FAB-M4/M5 patients have decreased susceptibility to the Bcl-2 inhibitor venetoclax, and this seems to be due to common molecular characteristics involving mitochondrial regulation of the cellular metabolism and survival, including decreased dependency on Bcl-2 compared to other AML patients. Thus, the susceptibility to Bcl-2 inhibition does not only depend on general resistance/susceptibility mechanisms known from conventional AML therapy but also specific mechanisms involving the molecular target itself or the molecular context of the target. AML cell differentiation status is also associated with susceptibility to other targeted therapies (e.g., CDK2/4/6 and bromodomain inhibition), and differentiation induction seems to be a part of the antileukemic effect for several targeted anti-AML therapies. Differentiation-associated molecular mechanisms may thus become important in the future implementation of targeted therapies in human AML.

Expression Pattern of Estrogen Receptor Alpha and Progesterone Receptor in Gallbladder Carcinoma and Their Association with Clinicopathological Parameters and Overall Survival.

Gallbladder cancer (GBC) is a highly aggressive malignant tumor with a poor prognosis. Despite being first described two centuries ago, there are no targeted therapies available beyond conventional cytotoxic therapy. Epidemiological studies have shown that the incidence of gallbladder cancer is higher in females than males. This suggests that the gallbladder may be a female sex hormone-responsive organ, and these hormones might be involved in the pathogenesis of gallbladder cancer. Therefore, we aimed to analyze the expression of ERα and PR in GBC and correlate their expression with clinicopathological variables and overall survival. A total of 235 histopathologically diagnosed GBC cases were included in this hospital-based cross-sectional study. Clinicopathological data were collected, and the expression of ERα and PR was evaluated by immunohistochemistry. The mean age of this study population was 55.47 ± 8.45 with range 28-87years. Females were predominated over male with a male-to-female ratio of 1:3.5. Positive nuclear expression of the ERα and PR was found in 13 (5.5%) and eight (3.4%) cases, respectively. Apart from nuclear staining, cytoplasmic expression of ERα and PR was found in three (1.2%) and 31 (13.2%) cases, respectively. Higher percentage of positive nuclear expression of ER was found in < 50years age (p value = 0.04), parity > 4 (p value = 0.02), advanced pT stage (T3) (p value = 0.01), lymphovascular invasion (p value = 0.02), and liver invasion (p value = 0.04) which were statistically significant. Higher percentage of PR expression was also observed in < 50years age (p value = 0.01), and tumor associated with gallstone (p value = 0.04). There was no significant correlation between cytoplasmic expression of ER, PR, and clinicopathological variables. In multivariate analysis, there was no significant correlation between ER or PR positive expression and overall survival. Although nuclear expression of ERα was significantly associated with progressive disease factors but the positive expression was found in very small percentage of GBC cases. So anti-hormone therapy might be an option in patient with ER α positive gallbladder carcinoma.

Association of Geriatric Nutritional Risk Index With Immune Checkpoint Inhibitor Treatment Duration and Adverse Events in Lung Cancer.

Compared to conventional cytotoxic anticancer agent-based therapy, treatment with immune checkpoint inhibitors (ICI) significantly prolongs overall survival. The Geriatric Nutritional Risk Index (GNRI) has been used as a new prognostic indicator in cancer. As nutritional status is associated with prognosis and indicates treatment response, we investigated the effect of the pretreatment GNRI on the (1) occurrence of ICI-induced immune-related adverse events (ir-AE) and (2) association with time to treatment failure (TTF) in ICI monotherapy for lung cancer. In this study, 127 patients with lung cancer who were treated with ICI monotherapy were retrospectively enrolled. Based on a cutoff value of 92 for the GNRI, we investigated intergroup differences in the occurrence of adverse events and their association with TTF in the High-GNRI (≥92) and Low-GNRI (<92) groups. For intergroup comparisons, we used the Student's t-test, Welch's t-test, Fisher's direct probability test, and Mann-Whitney's U-test, and factors with p<0.05 in the intergroup comparison were extracted as explanatory variables. Based on the pretreatment GNRI, the median TTF was 5.1 months (95%CI=2.4-7.9 months) in the High-GNRI group and 2.3 months (95%CI=1.6-3.1 months) in the Low-GNRI group, with the High-GNRI group having a significantly longer TTF (p<0.01). The incidence of skin rash (p=0.0129) and pruritus (p<0.01) was significantly higher in the High-GNRI group. Pretreatment GNRI influences the continuation of ICI monotherapy. The High-GNRI group demonstrated a significantly higher frequency of skin lesions, which may have influenced the prolongation of TTF.

Precision Deuteration in Search of Anticancer Agents: Approaches to Cancer Drug Discovery.

Cancer chemotherapy has been shifted from conventional cytotoxic drug therapy to selective and target-specific therapy after the findings about DNA changes and proteins that are responsible for cancer. A large number of newer drugs were discovered as targeted therapy for particular types of neoplastic disease. The initial discovery includes the development of the first in the category, imatinib, a Bcr-Abl tyrosine kinase inhibitor (TKI) for the treatment of chronic myelocytic leukemia in 2001. But the joy did not last for long as the drug developed a point mutation within the ABL1 kinase domain of BCR-ABL1, which subsequently led to the discovery of many other TKIs. Resistance was observed for newer TKIs a few years after their launching, but the use of TKIs in life-threatening cancer therapy is considered as far better compared with the risks of disease because of its target specificity and hence less toxicity. In search of a better anticancer agent, the physiochemical properties of the lead molecule have been modified for its efficacy toward disease and delay in the development of resistance. Deuteration in the drug molecule is one of such modifications that alter the pharmacokinetic properties, generally its metabolism, as compared with its pharmacodynamic effects. Precision deuteration in many anticancer drugs has been carried out to search for better drugs for cancer. In this review, the majority of anticancer drugs and molecules for which deuteration was applied to get better anticancer molecules were discussed. This review will provide a complete guide about the benefits of deuteration in cancer chemotherapy.

Use of daunorubicin and cytarabine in adults with acute myeloid leukemia and associated risk factors for inpatient mortality: National inpatient sample review.

e19029 Background: According to American Cancer Society’s 2023 estimates, Acute Myeloid Leukemia (AML) is the most common leukemia in adults, involving up to 34% of new cases in the United States. The conventional cytotoxic therapy in AML involves induction therapy with cytarabine and an anthracycline daunorubicin or idarubicin. The purpose of this study was to assess patient traits and disease variables augmenting mortality risk in AML patients treated with cytarabine and daunorubicin. Methods: We used the 2016-2020 National inpatient sample (NIS), via SPSS 29. 0, to find adult patients with a diagnosis of AML and use of Daunorubicin/Cytarabine. Several patient characteristics and comorbidities such as sex, race, obesity, diabetes, and hypertension were identified. The mortality rate among these patients were estimated and logistic regression models were used to report risk factors of mortality and their associated adjusted odds ratio and 95% confidence interval (95% CI). Results: Our analysis found 6695 cases of AML using Daunorubicin/Cytarabine. Among them 47.1% were above the age of 60, 45.7% were covered under private insurance, 71.8% were of White race, 54.4% were males and 31.8% were smokers. 10.3% of patients were admitted on the weekend. Various comorbidities were seen including diabetes (14.7%), obesity (13.0%), hypertension (32.9%), history of old myocardial infarction (2.5%), and cirrhosis (3.0%). While admitted, patients experienced a range of side effects and complications including fever (2.2%), nausea and vomiting (9.4%), weakness or malaise or fatigue (4.4%), septicemia (18.6%), Acute Kidney Injury (AKI) (18.5%), cardiac dysrhythmias (16.0%), cardiogenic shock (0.5%) and secondary or unspecified thrombocytopenia (21.0%). Unfortunately, 415 patients died (6.2%) during hospitalization. A higher risk of mortality was seen in weekend admissions (aOR 1.687, 95% CI 1.227-2.318, p &lt; 0.01), those who developed septicemia (aOR 7.859, 95% CI 6.076-10.164, p &lt; 0.01), and AKI (aOR 3.095, 95% CI 2.396-3.998, p &lt; 0.01). Mortality risk was also higher in those with cirrhosis (aOR 6.367, 95% CI 4.139-9.794, p &lt; 0.01) and age more than 60 (aOR 3.174, 95% CI 2.275-4.428, p &lt; 0.01). However, a lower mortality risk was seen in patients with hypertension (aOR 0.689, 95% CI 0.518-0.918, p = 0.011). Conclusions: Various factors such as weekend admissions, septicemia, AKI, cirrhosis, and age &gt; 60 were associated with poorer outcomes while hypertensive patients had a lower mortality rate. The drawbacks of this study were that complications and side effects couldn't be quantified in proportion to doses or number of cycles received post induction with or without consolidation therapy with cytarabine and daunorubicin. Further studies in clinical settings should investigate the various disparities observed in our study.

Basal-like mammary carcinomas stimulate cancer stem cell properties through AXL-signaling to induce chemotherapy resistance.

Basal-like breast cancer (BLBC) is the most aggressive and heterogeneous breast cancer (BC) subtype. Conventional chemotherapies represent next to surgery the most frequently employed treatment options. Unfortunately, resistant tumor phenotypes often develop, resulting in therapeutic failure. To identify the early events occurring upon the first drug application and initiating chemotherapy resistance in BLBC, we leveraged the WAP-T syngeneic mammary carcinoma mouse model and we developed a strategy combining magnetic-activated cell sorting (MACS)-based tumor cell enrichment with high-throughput transcriptome analyses. We discovered that chemotherapy induced a massive gene expression reprogramming toward stemness acquisition to tolerate and survive the cytotoxic treatment in vitro and in vivo. Retransplantation experiments revealed that one single cycle of cytotoxic drug combination therapy (Cyclophosphamide, Adriamycin and 5-Fluorouracil) suffices to induce resistant tumor cell phenotypes in vivo. We identified Axl and its ligand Pros1 as highly induced genes driving cancer stem cell (CSC) properties upon chemotherapy in vivo and in vitro. Furthermore, from our analysis of BLBC patient datasets, we found that AXL expression is also strongly correlated with CSC-gene signatures, a poor response to conventional therapies and worse survival outcomes in those patients. Finally, we demonstrate that AXL inhibition sensitized BLBC-cells to cytotoxic treatment in vitro. Together, our data support AXL as a promising therapeutic target to optimize the efficiency of conventional cytotoxic therapies in BLBC.

Transplant for TP53-mutated MDS and AML: because we can or because we should?

TP53 mutations impair the cellular response to genotoxic stress and drive intrinsic resistance to conventional cytotoxic therapies. Clinical outcomes in patients with TP53-mutated myeloid malignancies are poor and marked by high-risk clinical features, such as complex karyotype and prior exposure to leukemogenic therapies, and short survival due to a high risk of relapse after allogeneic transplantation. TP53 mutations are thus included as adverse markers in clinical prognostic models, including European LeukemiaNet recommendations and the Molecular International Prognostic Scoring System for myelodysplastic syndromes (MDS). Recent data indicate that the TP53 allelic state, co-occurring somatic mutations, and the position of the TP53 mutation within the clonal hierarchy define genetic heterogeneity among TP53-mutated MDS and acute myeloid leukemia that may influence clinical outcomes, thereby informing the selection of patients most suitable for transplantation. Further, novel therapeutic methods such as antibody-based agents (monoclonals or dual-affinity retargeting antibodies), cellular therapies (natural killer cells, chimeric antigen receptor T cells), or targeted agents (eprenetapopt) may offer opportunities to modify the approach to pretransplant conditioning or posttransplant maintenance and improve clinical outcomes.

DNAR-05. A ROLE FOR TAZ/YAP IN DNA DAMAGE REPAIR IN GLIOBLASTOMA

Abstract Previous studies have shown that glioma stem-like cells (GSCs) evade conventional cytotoxic therapies and repopulate as recurrent tumors. A fuller understanding of the molecular mechanisms underlying the biology and therapy resistance of GSCs is required. Our group has shown that TAZ, a transcriptional co-factor is highly expressed in about 70% of glioblastomas (GBMs). TAZ and its paralog YAP are oncogenic drivers of brain tumor progression. GSCs overexpressing TAZ undergo a proneural (PN) to mesenchymal (MS) subtype transition, which is accompanied by aggressive phenotypes such as increased grade and treatment resistance in GSC xenografts. Although the oncogenic functions of TAZ/YAP are well established, the exact molecular mechanisms underlying TAZ/YAP mediated cell fate transition and therapy resistance in GBM are not fully understood. Here, we present novel functional interaction between TAZ/YAP and DNA-dependent protein kinase (DNA-PK) in response to exposure to ionizing radiation in GSCs. Mass-spectrometric analyses of TAZ-binding proteins showed that DNA-PK complex composed of the catalytic subunit (DNA-PKcs) and a Ku heterodimer of Ku70 and K80 interacted with TAZ. Immunoprecipitation of DNA-PK showed interaction of both YAP as well. Interaction of YAP/TAZ with DNA-PK complex and TEAD was enhanced by ionizing radiation. DNA-PKcs phosphorylated both YAP and TAZ, and phosphorylation level of these proteins were increased after irradiation, consistent with an increased interaction of these proteins. Intriguingly, siRNA knockdown of YAP and TAZ resulted in inactivation of DNA-PKcs, although protein stability of DNA-PKcs was not affected. Pharmacological inhibition of TAZ/YAPTEAD resulted in increased DNA damage and suppressed cell proliferation, and this effect was synergized by irradiation. We conclude that TAZ and YAP are integral components of DNA damage response and that pharmacological targeting of TAZ/YAP/TEAD pathway can overcome radiation resistance in GSCs.

Checkpoint inhibitor immunotherapy diminishes oocyte number and quality in mice.

Loss of fertility is a major concern for female reproductive-age cancer survivors, since a common side-effect of conventional cytotoxic cancer therapies is permanent damage to the ovary. While immunotherapies are increasingly becoming a standard of care for many cancers-including in the curative setting-their impacts on ovarian function and fertility are unknown. We evaluated the effect of immune checkpoint inhibitors blocking programmed cell death protein ligand 1 and cytotoxic T lymphocyte-associated antigen 4 on the ovary using tumor-bearing and tumor-free mouse models. We find that immune checkpoint inhibition increases immune cell infiltration and tumor necrosis factor-α expression within the ovary, diminishes the ovarian follicular reserve and impairs the ability of oocytes to mature and ovulate. These data demonstrate that immune checkpoint inhibitors have the potential to impair both immediate and future fertility, and studies in women should be prioritized. Additionally, fertility preservation should be strongly considered for women receiving these immunotherapies, and preventative strategies should be investigated in future studies.

Abstract 2600: AsiDNA® treatment protects healthy cells from anticancer treatment toxicity

Abstract Purpose: Conventional cytotoxic therapies are still the standard of care for the treatment of many cancers. However, the associated severe side effects, especially damage to normal proliferating cells like stem and progenitor cells, often lead to drug dose reduction, which limits treatment success. Indeed, chemotherapy-induced myelosuppression is manifested by neutropenia, lymphopenia, anemia, and thrombocytopenia. Although growth factors ameliorate this myelosuppression, their efficacy is still suboptimal and lineage specific. Pre-clinical and clinical studies have shown that AsiDNA, a double-stranded (DS) DNA molecule that mimics DS DNA breaks to interfere with DNA repair by over-activating a false DNA damage signaling through DNA-PK and PARP enzymes (decoy agonist), is extremely well tolerated in standalone in mammals. These observations led us to assess the potential of AsiDNA to protect healthy cells from toxicities of several anti-cancer treatments. Experimental design: In vivo, we analyzed the safety profile of AsiDNA during a recent clinical trial (DRIIV-1b/NCT03579628) in combination with platinum-based chemotherapy. In vitro, we used isolated blood cells from healthy donors, and epithelial and fibroblast cells as models to study if AsiDNA could protect healthy cells to chemo- and radiotherapy-induced toxicity. We monitored cell survival, DNA damage (comet assays) and repair (53BP1 and Rad51 foci), DNA-PK (HSP90 and H2AX phosphorylation) and PARP (PARylation) activation, cell cycle modulation and p53 dependency to identify mechanisms underlying the effects of AsiDNA on healthy cells. Results: In vivo, long-term treatment of several patients with carboplatine+/-paclitaxel + AsiDNA showed no increase of chemotherapies toxicities allowing longer periods of disease control and suggesting a protective effect of AsiDNA. In the in vitro models, we showed that AsiDNA enters non dividing and dividing healthy cells as revealed by intracellular PARylation but induces its nuclear target engagement (H2AX and HSP90 phosphorylation) only in dividing cells. Association of AsiDNA to antitumor treatments increased survival of healthy proliferative cells. Interestingly, AsiDNA displayed two distinct mechanisms of protection depending on the origin of the cells: p53-dependent G1/S cell cycle arrest in fibroblasts and epithelial cells, and DNA repair “doping” in hematological cells revealed by higher recruitment of Rad51 and 53BP1 at damage sites in those cells. Enzymatic inhibition and gene editing revealed that hyperactivation of DNA-PK/p53 pathway by AsiDNA might be required for healthy cells preservation. Conclusion: These findings suggest that the combination of AsiDNA with anticancer treatments should provide a means to attenuate therapy-induced toxicity, while showing the well-documented synergy in tumor cells, thus providing an opportunity to increase the therapeutic window. Citation Format: Wael Jdey, Anouk Sesink, Agathe Cohendet, Juliette Rieu, Chloe Doizelet, Vincent Hayes, Pierre-Marie Girard, Marie Dutreix, Judith Greciet. AsiDNA® treatment protects healthy cells from anticancer treatment toxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2600.

A multicenter phase Ib/II study of liposomal-irinotecan, 5-fluorouracil (5-FU), and leucovorin (LV) with nivolumab as second-line therapy for patients with advanced biliary tract cancer (BilT-03).

438 Background: Patients (pts) with advanced biliary tract cancers (BTC) have poor prognosis despite systemic chemotherapy and treatment beyond first-line platinum doublet remains largely investigational. The immunomodulatory properties of conventional cytotoxic therapy, particularly in regard to the upregulation of PD-L1 expression rendering tumor cells less sensitive to T cell-mediated lysis, rapid emergence of chemotherapy resistance, and known modest efficacy of single agent anti-PD-1 antibody in BTC provide a rationale for combination chemoimmunotherapy. We conducted a multi-center, phase Ib/II, single-arm study to investigate the role of liposomal-irinotecan, 5FU and LV in combination with nivolumab as second-line therapy in pts with advanced BTC. Methods: Key eligibility criteria include histologically confirmed unresectable or metastatic BTC after progression or intolerance of first-line systemic therapy, measurable disease per RECISTv1.1, ECOG PS 0-1, and absence of autoimmune disease or chronic steroid use. The limited phase Ib portion evaluated 10 pts to determine the recommended phase 2 dose (RP2D) based on the probability of dose-limiting toxicity (DLT) rate &lt;30% during days 1-29. Study treatment included 5FU 2400 mg/m2 over 46 hrs, LV 400 mg/m2, liposomal-irinotecan 70 mg/m2 at dose level 0 along with nivolumab 240 mg every 2 wks for up to 2 yrs in absence of disease progression or unacceptable toxicity. The primary endpoint was median progression-free survival (PFS) rate with an alternative and null hypothesis of 5.0 mo and 2.9 mo (two-sided alpha 0.05, power 80%), respectively. Secondary endpoints included best overall response rate (ORR) per immune related (ir)RECIST, median overall survival (OS), 75th percentile estimates of PFS and OS, and safety. Exploratory objectives include biomarker analysis using include targeted panel exome/transcriptome and immune cell subsets in tissue. Results: 30 eligible pts (60% men, 83% Caucasian) including 10 pts in phase Ib and 20 pts in phase II with a median age of 63.5 yrs (range 36-75) were enrolled across 4 US sites between June 2019 and July 2021. In phase Ib, one pt experienced DLT (grade 3 enterocolitis); RP2D was confirmed at dose level 0. All 30 pts were included in study reported outcomes with a median follow-up time of 10.7 mo. Median PFS was 4.2 mo (95% CI, 1.9-10.2) and failed to reject the null hypothesis. Median OS was 7.5 mo (95% CI, 5.8-21.4). The 75th percentile estimates for PFS and OS are 10.2 mo (95% CI, 5.4-NE) and 21.4 mo (95% CI, 7.8-21.4). ORR estimates and toxicity data are pending and will be presented at the meeting. Conclusions: The observed median PFS is insufficient to reject the null hypothesis. The 75th percentile estimates for PFS and OS are suggestive of prolonged benefit with chemoimmunotherapy in a small fraction of patients with BTC. Clinical trial information: NCT03785873.

Lenalidomide and Rituximab (ReRi) As Front-Line Chemo-Free Therapy for Elderly Frail Patients with Diffuse Large B-Cell Lymphoma. a Phase II Study of the Fondazione Italiana Linfomi (FIL)

▪INTRODUCTIONTreatment of Diffuse Large B cell lymphoma (DLBCL) in the elderly population is challenging as many patients (pts) are not eligible to receive standard curative therapy, due to comorbid conditions and to a higher susceptibility to the side effects of standard anthracycline containing regimens.Among currently available active drugs, Lenalidomide has been used in the setting of relapsed/refractory DLBCL both as monotherapy and in combination with rituximab, showing a good activity and an acceptable safety profile.We started a prospective, multicenter, single arm, phase II trial to demonstrate activity and safety of a chemo-free combination of lenalidomide + rituximab in older (≥ 70 years) untreated pts with DLBCL who were prospectively defined as frail according to the simplified comprehensive geriatric assessment (sCGA) (Tucci A. et al., Leuk Lymphoma. 2015 Apr).PATIENTS AND METHODSPts were eligible if they were previously untreated DLBCL patients, older than 69 years and defined as frail according to sCGA.The treatment consisted of a 28-day cycle (R2) combining oral Lenalidomide (20 mg on days 1 to 21) and i.v. Rituximab (375 mg/m2 on day 1); a maximum number of 6 cycles was planned; response assessment was performed after cycles 4 and 6. At the end of the 6 th cycle, patients with partial or complete response continued treatment with Lenalidomide 10mg/d on days 1 to 21 every 28 days, until cycle 12or unacceptable toxicity. Final response was evaluated within 28 days after the last study drug administration. Primary study endpoint was Overall Response Rate (ORR) after 6 R2 cycles, defined according to Lugano 2014 criteria; co-primary endpoint was the rate of extra-hematological toxicity with CTCAE grade >2 and of death for any cause during the treatmentThe study was planned according to a two stage Simon design. A total of 68 pts had to be enrolled to complete the study. With 34 responses the study would be able to demonstrate the initial hypothesis of an improvement of response rate from 45% (p0) to 65% (P1)RESULTSFrom August 2018 to June 2021, 68 newly diagnosed frail DLBCL were enrolled in 18 Italian centers. Median age was 83 years (range 70-91) and 73% had stage III/IV; 57% had High risk IPI (i.e. 3-5 risk factors). 64 pts were confirmed eligible and started R2 treatment. The planned 6 courses of R2 were completed in 36 pts (56%). The median number of R2 cycles was 6 (1-6). Treatment was discontinued in 28 pts due to lymphoma progression (11 cases), extra-hematological toxicity (7), hematological toxicity (1), lost after 1 cycle and investigator choice after 5 cycles in CR in 1 case each, death in 7 cases (1 each for infection, pancytopenia, cachexia, ischemia and bowel infarction, and from unknown causes in 2 cases).At the end of 6 th R2 cycle 26 patients achieved a response (ORR 41%), 13 CR and 13 PR. After a median follow-up of 17 months, the overall survival, and progression free survival at 12 months were 69% (95CI 56-79%) and 55% (95%CI 42-66%), respectively. The duration of remission at 12 months was 72%.Regarding safety 46 events were reported including 31 extra-hematological toxicities > CTCAE grade 2: 7 cardio-vascular (1 resulting in death), 4 nervous system disorders (1 resulting in death), 10 gastro-intestinal, 3 infections, 6 skin and subcutaneous tissue disorders, 5 respiratory events (all resolved). The rate of grade 3-4 adverse events was higher than the highest allowed limit of 28.CONCLUSIONSThe Reri is the first study to evaluate activity and safety of a chemo-free therapy in patients with diffuse large B-Cell Lymphoma who are not eligible for conventional cytotoxic therapy. Even if this study was not able confirm the initial activity hypothesis, activity of the R2 combination was observed in a significant proportion of cases warranting further exploration of chemo-free approach of elderly frail patient with DLBCL. DisclosuresTucci: janssen: Membership on an entity's Board of Directors or advisory committees; Gentili: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees. Fabbri: Takeda: Honoraria; Servier/Pfizer: Honoraria; Takeda: Other: Travel, Accomodations, Expenses. Musuraca: janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; incyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Zilioli: Takeda: Other: travel expenses, accommodation; Gentili, Takeda, Gilead, Servier: Consultancy, Speakers Bureau; Roche, Italfarmaco: Consultancy, Honoraria; MSD, Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations. Luminari: Roche, Celgene, Teva Pharmaceuticals, Gilead Sciences, and Takeda Pharmaceuticals: Honoraria.

PH-0329 Feasibility and outcome of bridging RT pre CAR-T in DLBCL in one centre with a wide referral network

Purpose or Objective CD19 CAR-T therapy is the most effective salvage treatment for relapsed/refractory DLBCL. However the manufacture of CAR-T cells takes several weeks and patients (pts) are at risk of progression during this time and usually require some form of bridging therapy to contain their disease. Radiotherapy (RT) is an attractive bridging option, as the chance of response to further conventional cytotoxic therapy is low. RT is generally delivered in the window between apheresis and infusion and requires careful scheduling. The aim of this study is to evaluate the feasibility, toxicity and early outcome of bridging RT in a cohort of pts undergoing CAR-T therapy for DLBCL. Materials and Methods This was a prospective analysis of pts receiving bridging RT since the start of CAR-T programme at our institution. We collected data on pt demographics, disease and RT details, as well as outcomes including early response, relapse, survival and toxicity. Results (Table presented.) Between April 2019 & January 2021 a total of 27 pts have received bridging RT. Of these 23 have been infused (1 not infused due to COVID19, 1 due to cardiac function & 2 pending). The CAR-T therapy was delivered in 1 Haematology Institution, but bridging RT in 9 different referring centres. Pt and disease characteristics and RT details are shown in table 1. The median time from CT planning scan to start of RT was 10 days (4-42). The median time between apheresis and start of RT was 5 days (-37-21;3 patients received RT prior to apheresis at -37,-35 &-29 days) and median time between end of RT and CAR-T infusion was 19 days (10-116). No pts were delayed due to RT toxicity. Toxicity data was available for 22 pts. 10 (45.5%) reported no toxicity. Only 1 pt had grade 3 toxicity (vomiting & diarrhoea) and RT was stopped. The most common toxicities were skin reaction (n=5) & fatigue (n=4). 25/27 (92.6%) pts underwent a PET-CT between bridging RT & infusion. In 22 (88%) pts there was response in treatment field (CMR=2, PMR=20). In 13 (59.1%) of those pts there was evidence of progressive disease (PD) outside the field, but none were prevented from receiving CAR-T infusion due to PD. With median FU of 8.8 (0.6-20.6) months from date of CAR-T infusion, 12/ 23 (52.2%) infused pts have relapsed, (2 infield, 5 out of field, 5 in both) with a local control rate of 69.6%;CMR (12;52.2%) and PMR (4;17.4%). 7 pts have died since infusion, 6 due to PD and 1 due to sepsis. Median PFS was 5.1 months (95% CI 0.0-11.9 months) and median OS 17.8 months (95% CI 12.7-22.9 months). 1 pt had infusion delayed due to COVID19 infection and died of PD. Conclusion RT was a safe and effective bridging option in this cohort of DLBCL pts pre CAR-T therapy. With close collaboration between Haematologists and Radiation Oncologists, it is possible to deliver a course of radical dose RT in the narrow window between apheresis and infusion, even across a wide geographical network. Further work is required to determine which pts benefit most from bridging RT and the optimal dose and schedule.

Bispecific T-Cell Engaging Antibodies Against MUC16 Demonstrate Efficacy Against Ovarian Cancer in Monotherapy and in Combination With PD-1 and VEGF Inhibition.

Immunotherapy for ovarian cancer is an area of intense investigation since the majority of women with relapsed disease develop resistance to conventional cytotoxic therapy. The paucity of safe and validated target antigens has limited the development of clinically relevant antibody-based immunotherapeutics for this disease. Although MUC16 expression is almost universal in High Grade Serous Ovarian Cancers, engagement of the shed circulating MUC16 antigen (CA-125) presents a theoretical risk of systemic activation and toxicity. We designed and evaluated a series of bispecific tandem single-chain variable fragments specific to the retained portion of human MUC16 ectodomain (MUC16ecto) and human CD3. These MUC16ecto- BiTEDs retain binding in the presence of soluble MUC16 (CA-125) and show cytotoxicity against a panel of ovarian cancer cells in vitro. MUC16ecto- BiTEDs delay tumor progression in vivo and significantly prolong survival in a xenograft model of ovarian peritoneal carcinomatosis. This effect was significantly enhanced by antiangiogenic (anti-VEGF) therapy and immune checkpoint inhibition (anti-PD1). However, the combination of BiTEDs with anti-VEGF was superior to combination with anti-PD1, based on findings of decreased peritoneal tumor burden and ascites with the former. This study shows the feasibility and efficacy of MUC16ecto- specific BiTEDs and provides a basis for the combination with anti-VEGF therapy for ovarian cancer.

Cancer Imaging in Immunotherapy.

Immune therapeutics are revolutionizing cancer treatments. In tandem, new and confounding imaging characteristics have appeared that are distinct from those typically seen with conventional cytotoxic therapies. In fact, only 10% of patients on immunotherapy may show tumor shrinkage, typical of positive responses on conventional therapy. Conversely, those on immune therapies may initially demonstrate a delayed response, transient enlargement followed by tumor shrinkage, stable size, or the appearance of new lesions. Response Evaluation Criteria in Solid Tumors (RECIST) or WHO criteria, developed to identify early effects of cytotoxic agents, may not provide a complete evaluation of new emerging treatment response pattern of immunotherapeutic agents. Therefore, new imaging response criteria, such as the immune-related Response Evaluation Criteria in Solid Tumors (irRECIST), immune Response Evaluation Criteria in Solid Tumors (iRECIST), and immune-related Response Criteria (irRC), are proposed. However, FDA approval of emerging therapies including immunotherapies still relies on the current RECIST criteria. In this chapter, we review the traditional and new imaging response criteria for evaluation of solid tumors and briefly touch on some of the more commonly associated immunotherapy-induced adverse events.

Molecular Mechanisms of Resistance to Anti-Angiogenic Drugs.

The problem of drug resistance in cancer patients has been well in mind from the beginning of modern medicine and oncology treatments with the so called conventional cytotoxic therapy. With the advent of target therapy against tumor angiogenesis and in particular against the vascular endothelial growth factor (VEGF)/VEGF receptor system, researchers thought that resistance could be no more a problem, since the low pattern of proliferation displayed by endothelial cells. However, beside the efficacy demonstrated by antiangiogenic drugs, resistance during prolonged drug treatments appears as a limiting feature. Nowadays, various mechanisms of resistance to antiangiogenic therapeutics have been discovered, either innate and depending on the host, or acquired by the tumor cells, especially as a consequence of induced hypoxia by antiangiogenic drugs and the redundancy of proangiogenic factors in the tumor microenvironment, and other forms of tumor neovascularization, than sprouting angiogenesis. Here, we have reviewed the preclinical and clinical evidence for mechanisms of resistance to antiangiogenic drugs reported so far. The knowledge of the mechanisms underneath antiangiogenic drug resistance could be of help in the choice of the more appropriate drug, the development of novel therapeutic strategies, the design of proper drug combination protocols or new formulations of antiangiogenic strategies.

Systemic CD4 Immunity as a Key Contributor to PD-L1/PD-1 Blockade Immunotherapy Efficacy.

PD-L1/PD-1 blockade immunotherapy has significantly improved treatment outcome for several cancer types compared to conventional cytotoxic therapies. However, the specific molecular and cellular mechanisms behind its efficacy are currently unclear. There is increasing evidence in murine models and in patients that unveil the key importance of systemic immunity to achieve clinical responses under several types of immunotherapy. Indeed, PD-L1/PD-1 blockade induces the expansion of systemic CD8+ PD-1+ T cell subpopulations which might be responsible for direct anti-tumor responses. However, the role of CD4+ T cells in PD-L1/PD-1 blockade-induced anti-tumor responses has been less documented. In this review we focus on the experimental data supporting the “often suspected” indispensable helper function of CD4 T cells towards CD8 effector anti-tumor responses in cancer; and particularly, we highlight the recently published studies uncovering the key contribution of systemic CD4 T cells to clinical efficacy in PD-L1/PD-1 blockade therapies. We conclude and propose that the presence of specific CD4 T cell memory subsets in peripheral blood before the initiation of treatments is a strong predictor of responses in non-small cell lung cancer patients. Therefore, development of new approaches to improve CD4 responses before PD-L1/PD-1 blockade therapy could be the solution to increase response rates and survival of patients.

Progress on Management of Penile Cancer in 2020.

Management of penile cancer represents a challenge to urologic oncologists due to the disease's rarity and sparse data in the literature. Squamous cell carcinoma represents the most common histologic subtype of penile cancer. Penile cancer has a disastrous effect on patients' psychological and physical health. Penile cancer accounts for approximately 1% of cancer deaths in the USA annually. However, in recent years, the management of penile cancer has achieved marked progress in both diagnostic and therapeutic approaches with the intent to avoid radical surgeries. The traditional total penile amputation has been replaced by penile preserving procedures in many patients. Nowadays, total penile amputation (total penectomy) is preserved only for patients with proximal lesions. The introduction of minimally invasive surgical techniques in the management of penile cancer-infiltrated lymph nodes has been reported. Given the dismal prognosis with conventional cytotoxic therapies, new systemic therapies have been investigated in patients with locally advanced or metastatic penile cancer. Multiple studies have shown promising outcomes. All these efforts have resulted in a remarkable improvement in patient quality of life. The objectives of our review are to update clinicians on the advances in the management of penile cancer and to summarize the recent guidelines and recommendations.

Brentuximab Vedotin with Chemotherapy in Frontline Treatment of Classic Hodgkin Lymphoma Nodular Sclerosis Syncytial Variant

BACKGROUND: Classic Hodgkin lymphoma (cHL) Nodular Sclerosis (NS) is the most common subtype of cHL and has a good prognosis. However, an uncommon variant of cHL NS, the syncytial variant (cHL NS-SV), represents an entity with a worse clinical outcome with conventional frontline cytotoxic therapy. Nevertheless, in the pivotal phase III study ECHELON-1, Brentuximab Vedotin (BV), doxorubicin, vinblastine, and dacarbazine (BV+AVD) while demonstrating a superior efficacy, unfortunately more febrile neutropenia (FN) and peripheral neuropathy (PN) were observed compared to bleomycin+AVD (ABVD) as frontline treatment of advanced-stage classical Hodgkin's lymphoma (cHL) (Straus et al Blood 2020). It is unknown whether BV combined with chemotherapy would improve the inferior prognosis of cHL NS-SV. METHODS: After obtaining institutional research approval, we retrospectively reviewed the characteristics and outcomes of adult cHL NS-SV patients, treated per physician preference with frontline BV combined with cytotoxic therapy, either as standard of care (SOC) or in a clinical trial (NCT01712490, NCT03646123 and NCT01060904) between 7/2010 and 7/2020. cHL NS-SV diagnosis was based on morphology and Immunophenotype. Bulky disease was defined as mass&amp;gt;10cm or mediastinal mass &amp;gt;1/3 of thoracic diameter at T5-T6. Lymph node regions were defined by the German Hodgkin Study Group (GHSG). Treatment consisted of 0.9 or 1.2 mg/kg of BV and standard dose ABVD or AVD or D, intravenously on days 1 and 15 of each 28-day cycle for up to 6 cycles. All patients received support with pegfilgrastim. Response assessment was based on positron emission tomography/computerized tomography (PET/CT). Follow-up time was calculated from the date of pre-treatment baseline lab measurement to relapse date or death date, whichever happened first. Patients with no event were censored at the last follow-up date. RESULTS: Among the 11 patients included in the analysis, the median age was 29 (range 19-59 years), 27.2% were female, and 90.9% were Caucasian. All patients had Eastern Cooperative Oncology Group (ECOG) 0-1, 72.7% of patients had B-symptoms and 81.9% had stage III or IV disease. The median size of the largest lesion was 9.0 cm, 45.5% of patients had bulky disease, 63.6% had extranodal disease, 72.7% had &amp;gt;3 GHSG involved nodal sites and median International Prognostic Score was 4. Overall, all patients received 6 cycles of therapy, 63.6% received BV+AVD, 27.3% received BV+ABVD and 1 patient received SOC BV with dacarbazine because of previous anthracycline exposure. The interim PET/CT showed response in all patients with Deauville score (DS) of 2-3 in 45.5% and 4 in 54.4%. The end-of-therapy PET/CT showed DS of 1-3 in 90.1% and 4 in 8.9%. The latter patient had the most voluminous bulk of this study. To date, no patient received additional systemic therapy or consolidative radiotherapy after completion induction therapy. With a median follow-up time of 14 months (range 5-82 months), no patient had relapse and all were still alive (Progression-Free Survival and Overall Survival of 100%). CONCLUSIONS: BV combined with cytotoxic therapy such as BV+AVD is a highly effective treatment strategy for patients with cHL NS-SV. Further studies are required to evaluate whether frontline therapy of BV+AVD could improve the outcome of the higher-risk subgroup cHL NS-SV. Table Disclosures Lee: Oncternal Therapeutics:Research Funding;Guidepoint Blogal:Consultancy;Aptitude Health:Speakers Bureau;Takeda:Research Funding;Seattle Genetics:Research Funding;Celgene:Research Funding;Bristol-Myers Squibb:Consultancy, Research Funding.

Immune characterization of pre-clinical murine models of neuroblastoma

Immunotherapy offers a potentially less toxic, more tumor-specific treatment for neuroblastoma than conventional cytotoxic therapies. Accurate and reproducible immune competent preclinical models are key to understanding mechanisms of action, interactions with other therapies and mechanisms of resistance to immunotherapy. Here we characterized the tumor and splenic microenvironment of two syngeneic subcutaneous (NXS2 and 9464D), and a spontaneous transgenic (TH-MYCN) murine model of neuroblastoma, comparing histological features and immune infiltrates to previously published data on human neuroblastoma. Histological sections of frozen tissues were stained by immunohistochemistry and immunofluorescence for immune cell markers and tumor architecture. Tissues were dissociated by enzymatic digestion, stained with panels of antibodies to detect and quantify cancer cells, along with lymphocytic and myeloid infiltration by flow cytometry. Finally, we tested TH-MYCN mice as a feasible model for immunotherapy, using prior treatment with cyclophosphamide to create a therapeutic window of minimal residual disease to favor host immune development. Immune infiltration differed significantly between all the models. TH-MYCN tumors were found to resemble immune infiltration in human tumors more closely than the subcutaneous models, alongside similar GD2 and MHC class I expression. Finally, TH-MYCN transgenic mice were administered cyclophosphamide alone or in combination with an anti-GD2 or anti-4-1BB monoclonal antibody, which resulted in increase in survival in both combination therapies. The TH-MYCN transgenic mouse is a promising in vivo model for testing immunotherapy compounds and combination therapy in a preclinical setting.