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Background: For patients with essential thrombocythaemia (ET) intolerant of or resistant to hydroxyurea (HU), interferon or anagrelide, there is a need for therapies with distinct MOAs that reduce thromboses, improve the patient experience and potentially offer distinct clinical benefits. Lysine-specific demethylase-1 (LSD1) is a histone H3K4 demethylase critical for the self-renewal potential of malignant myeloid cells and the differentiation of myeloid progenitors, e.g., LSD1 licenses progenitors to mature into megakaryocytes, a cell central to the pathogenesis of ET. IMG-7289 (bomedemstat) is an orally active LSD1 inhibitor that reduced peripheral cell counts, splenomegaly, inflammatory cytokines, and mutant cell burdens in mouse models of MPNs (Jutzi et al. 2018). In an ongoing study of IMG-7289 for the treatment of myelofibrosis (MF) (NCT03136185), symptoms, platelets, neutrophils, mutant allele burdens and inflammatory cytokines were favorably impacted (Pettit et al. 2020). Aim(s): IMG-7289-CTP-201 is an ongoing, multi-national, open-label, 24-week Phase 2b study of bomedemstat taken once daily in patients with ET who are resistant to or intolerant of at least one standard of care treatment (NCT04254978). Key objectives are safety and reduction in the platelet count to <=400k/muL in the absence of thromboembolic events. Dosing is individually tailored targeting a platelet count between 200- 400k/muL. All patients were started at a dose of 0.6mg/kg/d and titrated as needed to the target platelet count range. Method(s): At the censoring date (16 Feb 2021), 10 patients had enrolled. All patients remain on study. The median duration of treatment is 85 days (6-141). Median age, 66 years (55-84), 20% males. 60% were deemed resistant to or intolerant of HU (by ELN criteria), 20% to anagrelide and 10% to interferon or busulfan. 40% had received at least one additional previous treatment. After a 14- to 28-day washout of prior ET treatment, the mean platelet and WBC co

Aim: Primary Central Nervous System Lymphoma (PCNSL) [i.e. diffuse large B-cell lymphoma of the CNS] is a rare and poor-prognosis disease occurring predominantly in older patients (median age >60 years old). Prospective studies of two commonly used chemoimmunotherapy (CIT) protocols, MATRix and MPV/Ara-C (+/- rituximab), have reported 2-year PFS and OS of 57-61% and 69-81% respectively. Our aim was to evaluate registry-reported outcomes of frontline CIT strategies employed at Australasian sites. Method(s): A retrospective study of consecutive, immunocompetent, adult PCNSL patients (WHO criteria: 2017) treated with curative-intent CIT, from 10 sites (9 Australian, 1 Singaporean) between 1 st January 2009 and 31 st December 2018 (i.e. ten-year period). Overall survival (OS) and progression-free survival (PFS) were calculated using the Kaplan-Meier (log-rank) method. Univariate associations were derived using a Cox model with variables p<0.10 entered stepwise into a multivariate model. Result(s): Data was collected on 207 patients, 189 of whom met WHO diagnostic criteria for PCNSL (i.e. diffuse large B-cell lymphoma of the CNS). We excluded patients with insufficient data (6), non-DLBCL histology (6), secondary PCNSL (3) and post-transplant lymphoproliferative disorder (3). Of these, 176 (93%) received curative-intent CIT. The majority (66%) were over 65 years of age (median: 65, range: 25-87); ECOG performance status was >= 2 in 31% (data not available for 14% of patients). The majority were male (55%) and had deep structure involvement (64%). International Extranodal Lymphoma Study Group (IELSG) risk criteria could not be calculated in many patients due to missing data (predominantly LDH and CSF protein). CSF involvement was rare (n=23, 13%) but data was only available for 60% of patients. Of the 159 with documented renal function, 26% had renal impairment (defined as Cockroft-Gault creatinine clearance <60ml/min or eGFR <90ml/min). Five CIT regimens were used: MATRi

Background: MCL is a rare and incurable disease representing 5-10% of all non-Hodgkin lymphoma cases. Although intensive chemotherapy induction and up-front ASCT can induce durable remissions in fit patients, toxicity can be significant. R-DHAOx chemoimmunotherapy provides adequate outcomes and a favourable toxicity profile compared to some other induction regimens (Le Gouill S Blood 2017). The highly selective Bruton tyrosine kinase inhibitor (BTKi) acalabrutinib has minimal off-target activity and proven efficacy in relapsed MCL (Wang M Lancet 2018), however, direct combination of BTKi & chemoimmunotherapy is toxic. Thus, it is postulated that up-front use with an acalabrutinib 'window' before chemoimmunotherapy, followed by maintenance after intensive chemotherapy will prolong time to next treatment and reduce overall treatment toxicity (Kuruvilla J Hematol Oncol 2017). Method(s): The WAMM study is an ALLG-sponsored investigator-initiated multicentre single-arm phase 2 trial (ACTRN1269000990123). Eligible patients are aged 18-70 years with previously-untreated histologically-proven CD20-positive stage II-IV MCL (all subtypes), ECOG 0-1, and no comorbidities precluding ASCT. Patient with major contraindications to BTKi use are excluded. Treatment is delivered in a unique and innovative acalabrutinib 'sandwich' design to avoid excess toxicity of combination acalabrutinib-chemoimmunotherapy (see figure). All patients receive 2 cycles of induction rituximab (R) 375 mg/m 2 IV (day 1) & acalabrutinib (A) 100mg BD PO daily (continuous) 4-weekly, followed by 4 conventional R-DHAOx chemoimmunotherapy cycles. Patients then undergo positron emission tomography (PET) assessment. Those with partial or complete response will proceed to carmustine, etoposide, cytarabine and melphalan (BEAM) autograft which is followed by A+R maintenance (A; 100 mg BD continuous for 1 year & R; 375 mg/m 2 IV, 3-monthly x 8 cycles). Patients with stable or progressive disease will be taken off st

Background Modern antiretroviral therapy (ART) has reduced HIV associated morbidity and mortality, and allowed a similar treatment approach of aggressive lymphomas in PLWH to that of their HIV negative counterparts. Australia is an ethnically diverse country with a low HIV prevalence and an excellent population-wide ART coverage and adherence in PLWH. We aimed to describe the real-world Australian experience in managing PLWH diagnosed with diffuse large B cell lymphoma (DLBCL) and Burkitt lymphoma (BL), and compare our treatment approach and outcomes against international data. Methods This was a retrospective, multicenter study conducted by the Australasian Lymphoma Alliance across 6 centers in 5 states. HIV positive patients with biopsy proven BL and DLBCL, diagnosed between 1st January 2009 and 31st December 2019 were identified through each institution's database. Baseline patient and disease characteristics, treatment exposure and outcomes were extracted from hospital medical records. Descriptive statistics, and survival analyses were performed as appropriate. Results 44 patients (24 DLBCL, 20 BL) were included in the analysis. The median age was 52 years (range 32-78). The median follow-up was 1.8 years (range 0.1-13.1). 36 (82%) patients presented with advanced stage (III-IV) disease. 28 (64%) were defined as high-risk based on disease specific IPI scoring systems. The mean CD4 count was 334 cells/muL at diagnosis and 10 (23%) patients had a CD4 count of <100 cells/muL. 23 (52%) had a HIV viral load <50 copies/ml. 12 (27%) were diagnosed with HIV at the time of lymphoma diagnosis (Mean CD4 count 191 cells/muL, mean viral load 665,612 copies/ml). 41 (93%) patients received chemotherapy with curative intent and 39 (88%) received Rituximab. 37 (84%) were given concurrent ART and chemo(immuno)therapy. 11 (55%) of BL patients were treated with CODOX-M/IVAC or HyperCVAD followed by 6 (30%) with Da-EPOCH. 14 (58%) of DLBCL patients received CHOP-based therapy with 1

Background: For patients with essential thrombocythaemia (ET) intolerant of or resistant to hydroxyurea (HU), interferon or anagrelide, there is a need for therapies with distinct MOAs that reduce thromboses, improve the patient experience and potentially offer distinct clinical benefits. Lysine-specific demethylase-1 (LSD1) is a histone H3K4 demethylase critical for the self-renewal potential of malignant myeloid cells and the differentiation of myeloid progenitors, e.g., LSD1 licenses progenitors to mature into megakaryocytes, a cell central to the pathogenesis of ET. IMG-7289 (bomedemstat) is an orally active LSD1 inhibitor that reduced peripheral cell counts, splenomegaly, inflammatory cytokines, and mutant cell burdens in mouse models of MPNs (Jutzi et al. 2018). In an ongoing study of IMG-7289 for the treatment of myelofibrosis (MF) (NCT03136185), symptoms, platelets, neutrophils, mutant allele burdens and inflammatory cytokines were favorably impacted (Pettit et al. 2020). Aim(s): IMG-7289-CTP-201 is an ongoing, multi-national, open-label, 24-week Phase 2b study of bomedemstat taken once daily in patients with ET who are resistant to or intolerant of at least one standard of care treatment (NCT04254978). Key objectives are safety and reduction in the platelet count to <=400k/muL in the absence of thromboembolic events. Dosing is individually tailored targeting a platelet count between 200- 400k/muL. All patients were started at a dose of 0.6mg/kg/d and titrated as needed to the target platelet count range. Method(s): At the censoring date (16 Feb 2021), 10 patients had enrolled. All patients remain on study. The median duration of treatment is 85 days (6-141). Median age, 66 years (55-84), 20% males. 60% were deemed resistant to or intolerant of HU (by ELN criteria), 20% to anagrelide and 10% to interferon or busulfan. 40% had received at least one additional previous treatment. After a 14- to 28-day washout of prior ET treatment, the mean platelet and WBC co

Aim: Primary Central Nervous System Lymphoma (PCNSL) [i.e. diffuse large B-cell lymphoma of the CNS] is a rare and poor-prognosis disease occurring predominantly in older patients (median age >60 years old). Prospective studies of two commonly used chemoimmunotherapy (CIT) protocols, MATRix and MPV/Ara-C (+/- rituximab), have reported 2-year PFS and OS of 57-61% and 69-81% respectively. Our aim was to evaluate registry-reported outcomes of frontline CIT strategies employed at Australasian sites. Method(s): A retrospective study of consecutive, immunocompetent, adult PCNSL patients (WHO criteria: 2017) treated with curative-intent CIT, from 10 sites (9 Australian, 1 Singaporean) between 1 st January 2009 and 31 st December 2018 (i.e. ten-year period). Overall survival (OS) and progression-free survival (PFS) were calculated using the Kaplan-Meier (log-rank) method. Univariate associations were derived using a Cox model with variables p<0.10 entered stepwise into a multivariate model. Result(s): Data was collected on 207 patients, 189 of whom met WHO diagnostic criteria for PCNSL (i.e. diffuse large B-cell lymphoma of the CNS). We excluded patients with insufficient data (6), non-DLBCL histology (6), secondary PCNSL (3) and post-transplant lymphoproliferative disorder (3). Of these, 176 (93%) received curative-intent CIT. The majority (66%) were over 65 years of age (median: 65, range: 25-87); ECOG performance status was >= 2 in 31% (data not available for 14% of patients). The majority were male (55%) and had deep structure involvement (64%). International Extranodal Lymphoma Study Group (IELSG) risk criteria could not be calculated in many patients due to missing data (predominantly LDH and CSF protein). CSF involvement was rare (n=23, 13%) but data was only available for 60% of patients. Of the 159 with documented renal function, 26% had renal impairment (defined as Cockroft-Gault creatinine clearance <60ml/min or eGFR <90ml/min). Five CIT regimens were used: MATRi

Background Modern antiretroviral therapy (ART) has reduced HIV associated morbidity and mortality, and allowed a similar treatment approach of aggressive lymphomas in PLWH to that of their HIV negative counterparts. Australia is an ethnically diverse country with a low HIV prevalence and an excellent population-wide ART coverage and adherence in PLWH. We aimed to describe the real-world Australian experience in managing PLWH diagnosed with diffuse large B cell lymphoma (DLBCL) and Burkitt lymphoma (BL), and compare our treatment approach and outcomes against international data. Methods This was a retrospective, multicenter study conducted by the Australasian Lymphoma Alliance across 6 centers in 5 states. HIV positive patients with biopsy proven BL and DLBCL, diagnosed between 1st January 2009 and 31st December 2019 were identified through each institution's database. Baseline patient and disease characteristics, treatment exposure and outcomes were extracted from hospital medical records. Descriptive statistics, and survival analyses were performed as appropriate. Results 44 patients (24 DLBCL, 20 BL) were included in the analysis. The median age was 52 years (range 32-78). The median follow-up was 1.8 years (range 0.1-13.1). 36 (82%) patients presented with advanced stage (III-IV) disease. 28 (64%) were defined as high-risk based on disease specific IPI scoring systems. The mean CD4 count was 334 cells/muL at diagnosis and 10 (23%) patients had a CD4 count of <100 cells/muL. 23 (52%) had a HIV viral load <50 copies/ml. 12 (27%) were diagnosed with HIV at the time of lymphoma diagnosis (Mean CD4 count 191 cells/muL, mean viral load 665,612 copies/ml). 41 (93%) patients received chemotherapy with curative intent and 39 (88%) received Rituximab. 37 (84%) were given concurrent ART and chemo(immuno)therapy. 11 (55%) of BL patients were treated with CODOX-M/IVAC or HyperCVAD followed by 6 (30%) with Da-EPOCH. 14 (58%) of DLBCL patients received CHOP-based therapy with 1

Background: MCL is a rare and incurable disease representing 5-10% of all non-Hodgkin lymphoma cases. Although intensive chemotherapy induction and up-front ASCT can induce durable remissions in fit patients, toxicity can be significant. R-DHAOx chemoimmunotherapy provides adequate outcomes and a favourable toxicity profile compared to some other induction regimens (Le Gouill S Blood 2017). The highly selective Bruton tyrosine kinase inhibitor (BTKi) acalabrutinib has minimal off-target activity and proven efficacy in relapsed MCL (Wang M Lancet 2018), however, direct combination of BTKi & chemoimmunotherapy is toxic. Thus, it is postulated that up-front use with an acalabrutinib 'window' before chemoimmunotherapy, followed by maintenance after intensive chemotherapy will prolong time to next treatment and reduce overall treatment toxicity (Kuruvilla J Hematol Oncol 2017). Method(s): The WAMM study is an ALLG-sponsored investigator-initiated multicentre single-arm phase 2 trial (ACTRN1269000990123). Eligible patients are aged 18-70 years with previously-untreated histologically-proven CD20-positive stage II-IV MCL (all subtypes), ECOG 0-1, and no comorbidities precluding ASCT. Patient with major contraindications to BTKi use are excluded. Treatment is delivered in a unique and innovative acalabrutinib 'sandwich' design to avoid excess toxicity of combination acalabrutinib-chemoimmunotherapy (see figure). All patients receive 2 cycles of induction rituximab (R) 375 mg/m 2 IV (day 1) & acalabrutinib (A) 100mg BD PO daily (continuous) 4-weekly, followed by 4 conventional R-DHAOx chemoimmunotherapy cycles. Patients then undergo positron emission tomography (PET) assessment. Those with partial or complete response will proceed to carmustine, etoposide, cytarabine and melphalan (BEAM) autograft which is followed by A+R maintenance (A; 100 mg BD continuous for 1 year & R; 375 mg/m 2 IV, 3-monthly x 8 cycles). Patients with stable or progressive disease will be taken off st

Background Stage I/II or early-stage follicular lymphoma (ESFL) is considered potentially curable with radiotherapy (XRT). While XRT does achieve local disease control in >90% of cases, more than half the patients (pts) relapse by 10 years (yr), generally outside of the radiation field. A recent randomized controlled trial (TROG 99.03) demonstrated that combined modality therapy (CMT), with sequential XRT and systemic therapy, significantly improved PFS but not overall survival (OS) compared to XRT alone in ESFL. However, only half the pts were staged with F-FDG positron emission tomography and computed tomography (PET) and 58% of CMT pts did not receive rituximab.Compared with CT staging, 20-60% of cases are upstaged by PET. Consequentially, there are limitations in applying this trial to modern populations. Despite the support of current guidelines, only one third of pts in clinical practice are treated with XRT. This suggests a need to better understand the role of other treatments, including watchful waiting (WW), in the PETera. Our aim was to compare outcomes with real-world treatment approaches in rigorously staged ESFL patients. Methods We conducted an international, multicenterretrospective study of stage I and II FL pts rigorously staged with bone marrow biopsy and PET. Eligible pts were >18yr with newly-diagnosed grade 1-3A FL and >=3 months follow up. Primary outcome measures were overall response rate (ORR), progression free survival (PFS), OS and risk of transformation. Survival curves were estimated with the Kaplan-Meier method and uni- and multivariate analysis was performed using Cox regression model. Results A total of 387 pts treated at 13 Australian and 3 Canadian centres between 2005-2017 were studied. Median follow-up was 45 months (range 3.1 - 164.0).5-yrPFS and OS rates were 73.5% (95% CI 66.0-78.5) and 94.4% (95% CI 89.4-93.6) respectively. 22 patients had stage IE duodenal FL with 5- yr PFS and OS rates of 100% and 100% respectively. Conside

Introduction: The optimal induction and conditioning regimen for patients with transplant eligible mantle cell lymphoma (MCL) remains unknown. Common approaches include the Nordic MCL2 regimen (rituximab (R), cyclophosphamide, vincristine, doxorubicin, prednisone (R-maxi-CHOP)) alternating with high-dose cytarabine (Geisler, Blood 2006) and R-Hyper CVAD/R-MA (hyperfractionated cyclophosphamide, vincristine, doxorubicin and dexamethasone alternating with high dose methotrexate/cytarabine) (Romaguera JCO 2005). The aim of this study was to compare the efficacy of different induction and conditioning regimens in transplant eligible MCL patients. Method(s): We performed a multi-center retrospective analysis of MCL patients treated with induction chemo-immunotherapy and deemed fit enough for autologous stem cell transplant (ASCT) between December 2001 and December 2015. Patients were excluded if they did not receive rituximab with induction chemotherapy. Transplant eligibility was determined by the treating physician and patients were included if fit enough to undergo ASCT regardless of whether it was subsequently performed. Patient characteristics, prognostic factors and outcomes following treatment were collected. We used appropriate descriptive statistics to compare baseline characteristics between treatment groups, and calculated progression free (PFS), overall survival (OS) and follow up from date of diagnosis to date of disease progression or death from any cause, or death from any cause, respectively. Patients alive at last observation were censored. We used univariate Cox regression to identify associations between prognostic factors and outcomes, and covariates with P-values <0.1 were included in a Cox multivariate regression. Result(s): We identified 228 patients and grouped them according to induction regimen received. Their baseline characteristics, treatment and outcomes are summarized in Table 1. Overall, the 5 groups were mostly balanced in terms of baseli

Introduction: The optimal induction and conditioning regimen for patients with transplant eligible mantle cell lymphoma (MCL) remains unknown. Common approaches include the Nordic MCL2 regimen (rituximab (R), cyclophosphamide, vincristine, doxorubicin, prednisone (R-maxi-CHOP)) alternating with high-dose cytarabine (Geisler, Blood 2006) and R-Hyper CVAD/R-MA (hyperfractionated cyclophosphamide, vincristine, doxorubicin and dexamethasone alternating with high dose methotrexate/cytarabine) (Romaguera JCO 2005). The aim of this study was to compare the efficacy of different induction and conditioning regimens in transplant eligible MCL patients. Method(s): We performed a multi-center retrospective analysis of MCL patients treated with induction chemo-immunotherapy and deemed fit enough for autologous stem cell transplant (ASCT) between December 2001 and December 2015. Patients were excluded if they did not receive rituximab with induction chemotherapy. Transplant eligibility was determined by the treating physician and patients were included if fit enough to undergo ASCT regardless of whether it was subsequently performed. Patient characteristics, prognostic factors and outcomes following treatment were collected. We used appropriate descriptive statistics to compare baseline characteristics between treatment groups, and calculated progression free (PFS), overall survival (OS) and follow up from date of diagnosis to date of disease progression or death from any cause, or death from any cause, respectively. Patients alive at last observation were censored. We used univariate Cox regression to identify associations between prognostic factors and outcomes, and covariates with P-values <0.1 were included in a Cox multivariate regression. Result(s): We identified 228 patients and grouped them according to induction regimen received. Their baseline characteristics, treatment and outcomes are summarized in Table 1. Overall, the 5 groups were mostly balanced in terms of baseli

Background: Bendamustine +/- anti-CD20 antibody is a highly effective regimen for iNHL. Though initially favoured for its toxicity profile, subsequent analyses demonstrate profound and prolonged lymphopenia and the landmark phase III GALLIUM study showed a grade 3-5 infection rate of 20-26% in the bendamustine arms (Hiddemann JCO 2018). The relationship between severity and duration of lymphopenia and infection, and the role of antimicrobial prophylaxis (ppx), are not fully characterised. We performed a multicentre, retrospective analysis of bendamustine-treated iNHL patients (pts) to define the type and onset of infections, identify concomitant risk factors and evaluate the role of ppx. Method(s): iNHL pts aged >=18 yrs, treated with bendamustine +/- anti-CD20 in 1st-3rd line from 2011-2019, were identified from 9 Australian centres. HIV, prior transplant and long-term immunosuppression were excluded. Demographics, treatment, lymphocyte counts, infections and ppx were collected from baseline to 24 months post end of bendamustine treatment (EOT) or subsequent lymphoma therapy. Association between potential risk factors and infection was evaluated by logistic regression (odds ratio, OR) and negative binomial regression (incidence rate ratio, IRR) with Stata 16.1. Result(s): 302 pts were eligible. Baseline and treatment characteristics are summarised in Table 1. 252 infection episodes occurred across 134 pts (44%), equally divided between during therapy and after EOT (Figure 1A, Table 2). Infections on treatment occurred in 30% of pts (n=92) with 18% hospitalised (n = 54; n = 20 with febrile neutropenia (FN)) and dose delay /modification/ discontinuation in 11%. Late infections post EOT occurred in 23% of pts (n=70) with 11% hospitalised (n = 32; n = 12 with FN); infection post EOT was more common in pts on maintenance anti-CD20 (infection rate 49% v 16%, OR 5.1 p<0.001). Opportunistic infections (OI) occurred in 21 pts: VZV (n=9; 4 on treatment, 5 post EOT, 1 on ppx)

Background The time to treatment initiation is determined by tumour burden in patients with follicular lymphoma (FL). The Groupe d'Etude des Lymphomes Folliculaires ('GELF') criteria, defined in the pre-rituximab era, are commonly used to assess tumour burden.2 Patients must meet >=1 of the following criteria to be considered "high" tumour burden according to GELF: any tumour mass >7 cm; >= 3 nodal sites (each >3 cm); B symptoms; splenomegaly; compression syndrome; pleural/peritoneal effusion; leukemic phase or cytopenias. Low tumour burden FL is often excluded from clinical trials, based on data from initial retrospective studies and later randomised trials, demonstrating no survival advantage with chemotherapy compared with observation alone. 1-3 Conversely, it is recommended those with high burden disease receive immediate therapy. The use of GELF in therapeutic decision-making outside of clinical trials is not well described. Methods Cases of newly diagnosed Grade 1-3a FL were retrospectively identified from the Australian Lymphoma and Related Diseases Registry (LaRDR), and 2 additional institutional databases from 2002-2019. Additional data was obtained from electronic hospital records. The primary aim of the study was to determine the utilisation of GELF criteria in guiding therapeutic decisions in FL. The secondary aims were to document frequency of GELF according to stage and treatment and to determine the impact of the number of GELF criteria on PFS. Survival analysis was calculated according to the Kaplan-Meier method. Results 385 cases were identified. Patient characteristics are in table 1. The median follow-up was 2 years (range 0.1-18) with 2-year PFS and OS of 89% (95% CI 85-92%) and 96% (95% CI 92-98%) respectively. 94 (24%) patients underwent a 'watch and wait' approach (W&W), 54 (14%) received radiotherapy alone and 237 (62%) received chemotherapy +/- radiotherapy. 118 (31%) patients had stage I/II disease at diagnosis, of these 36 (30%) underwent

Background: Bendamustine +/- anti-CD20 antibody is a highly effective regimen for iNHL. Though initially favoured for its toxicity profile, subsequent analyses demonstrate profound and prolonged lymphopenia and the landmark phase III GALLIUM study showed a grade 3-5 infection rate of 20-26% in the bendamustine arms (Hiddemann JCO 2018). The relationship between severity and duration of lymphopenia and infection, and the role of antimicrobial prophylaxis (ppx), are not fully characterised. We performed a multicentre, retrospective analysis of bendamustine-treated iNHL patients (pts) to define the type and onset of infections, identify concomitant risk factors and evaluate the role of ppx. Method(s): iNHL pts aged >=18 yrs, treated with bendamustine +/- anti-CD20 in 1st-3rd line from 2011-2019, were identified from 9 Australian centres. HIV, prior transplant and long-term immunosuppression were excluded. Demographics, treatment, lymphocyte counts, infections and ppx were collected from baseline to 24 months post end of bendamustine treatment (EOT) or subsequent lymphoma therapy. Association between potential risk factors and infection was evaluated by logistic regression (odds ratio, OR) and negative binomial regression (incidence rate ratio, IRR) with Stata 16.1. Result(s): 302 pts were eligible. Baseline and treatment characteristics are summarised in Table 1. 252 infection episodes occurred across 134 pts (44%), equally divided between during therapy and after EOT (Figure 1A, Table 2). Infections on treatment occurred in 30% of pts (n=92) with 18% hospitalised (n = 54; n = 20 with febrile neutropenia (FN)) and dose delay /modification/ discontinuation in 11%. Late infections post EOT occurred in 23% of pts (n=70) with 11% hospitalised (n = 32; n = 12 with FN); infection post EOT was more common in pts on maintenance anti-CD20 (infection rate 49% v 16%, OR 5.1 p<0.001). Opportunistic infections (OI) occurred in 21 pts: VZV (n=9; 4 on treatment, 5 post EOT, 1 on ppx)

Background The time to treatment initiation is determined by tumour burden in patients with follicular lymphoma (FL). The Groupe d'Etude des Lymphomes Folliculaires ('GELF') criteria, defined in the pre-rituximab era, are commonly used to assess tumour burden.2 Patients must meet >=1 of the following criteria to be considered "high" tumour burden according to GELF: any tumour mass >7 cm; >= 3 nodal sites (each >3 cm); B symptoms; splenomegaly; compression syndrome; pleural/peritoneal effusion; leukemic phase or cytopenias. Low tumour burden FL is often excluded from clinical trials, based on data from initial retrospective studies and later randomised trials, demonstrating no survival advantage with chemotherapy compared with observation alone. 1-3 Conversely, it is recommended those with high burden disease receive immediate therapy. The use of GELF in therapeutic decision-making outside of clinical trials is not well described. Methods Cases of newly diagnosed Grade 1-3a FL were retrospectively identified from the Australian Lymphoma and Related Diseases Registry (LaRDR), and 2 additional institutional databases from 2002-2019. Additional data was obtained from electronic hospital records. The primary aim of the study was to determine the utilisation of GELF criteria in guiding therapeutic decisions in FL. The secondary aims were to document frequency of GELF according to stage and treatment and to determine the impact of the number of GELF criteria on PFS. Survival analysis was calculated according to the Kaplan-Meier method. Results 385 cases were identified. Patient characteristics are in table 1. The median follow-up was 2 years (range 0.1-18) with 2-year PFS and OS of 89% (95% CI 85-92%) and 96% (95% CI 92-98%) respectively. 94 (24%) patients underwent a 'watch and wait' approach (W&W), 54 (14%) received radiotherapy alone and 237 (62%) received chemotherapy +/- radiotherapy. 118 (31%) patients had stage I/II disease at diagnosis, of these 36 (30%) underwent