Janssen. **Kalakonda, N:** Research Funding: Celgene. **Dreyling, M:** Consultant Advisory Role: Acerta Pharma, Bayer, Celgene, Gilead Sciences, Janssen, Novartis, Roche, and Sandoz; Honoraria: Bayer, Celgene, Gilead Sciences, Janssen, and Roche; Research Funding: Celgene, Janssen, Mundipharma, and Roche; Other Remuneration: Travel, accommodations and expenses from Celgene, Janssen, Roche, and Takeda. **Zinzani, P:** Consultant Advisory Role: Verastem, BMS, MSD, Johnson & Johnson, Servier, and Gilead; Honoraria: Verastem, BMS, MSD, Johnson & Johnson, Servier, and Gilead; Other Remuneration: Fees for participation in a speakers' bureau from Verastem, BMS, MSD, Johnson & Johnson, Servier, and Gilead. **Dinberger-Hertweck, M:** Employment Leadership Position: MorphoSys. **Weirather, J:** Employment Leadership Position: MorphoSys. **Ambarkhane, S:** Employment Leadership Position: MorphoSys. **Maddocks, K:** Consultant Advisory Role: AstraZeneca, Pharmacyclics, Bayer, Teva and Sandoz; Honoraria: AstraZeneca, Pharmacyclics, Bayer, Sandoz and Teva; Research Funding: Pharmacyclics, BMS, Novartis and Merck.

125
BET INHIBITOR RG6146, VENETOCLAX, AND RITUXIMAB IS A HIGHLY ACTIVE REGIMEN IN RELAPSED/REFRACTORY (R/R) DLBCL: INITIAL REPORT OF PHASE 1B SAFETY, BIOMARKER, AND RESPONSE DATA

M. Dickinson¹ | J. Briones Mejjide² | A.F. Herrera³ |

E. González Barca⁴ | N. Ghosh⁵ | R. Cordoba⁶ |

S.C. Rutherford⁷ | R. Advani⁸ | E. Bournazou⁹ |

E. Labriola-Tompkins⁹ | T. Friess¹⁰ | E. Chesne¹¹ |

J. Brouwer-Visser⁹ | K. Lechner¹⁰ | B. Brennan⁹ |

E. Nueesch¹¹ | M. De Mario⁹ | M. Hutchings¹²

¹Department of Haematology, Peter MacCallum Cancer Centre, Melbourne, Australia; ²Hematology Department, Hospital de la Santa Creu i Sant Pau, Sant Pau and Jose Carreras Leukemia Research Institutes, Barcelona, Spain; ³Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Duarte, United States; ⁴Haematology, Institut Català d'Oncologia, L'Hospitalet de Llobregat, Barcelona, Spain; ⁵Department of Hematologic Oncology and Blood Disorders, Levine Cancer Institute-Morehead, Charlotte, United States; ⁶Department of Haematology, Fundacion Jimenez Diaz University Hospital, Madrid, Spain; ⁷Meyer Cancer Center, Division of Hematology and Medical Oncology, New York Presbyterian Hospital/Weill Cornell Medicine, New York, United States; ⁸Blood and Marrow Transplant Program, Stanford Cancer Center, Palo Alto, United States; ⁹Roche Pharma Research and Early Development, Roche Innovation Center New York, New York, United States; ¹⁰Roche Pharma Research and Early Development, Roche Innovation Center Munich, Penzberg, Germany; ¹¹Roche Pharma Research and Early Development, Roche Innovation Center Basel, Basel, Switzerland; ¹²Department of Haematology and Phase 1 Unit, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark

**Introduction:** Outcomes of patients (pts) with R/R DLBCL are inferior after standard R-CHOP chemotherapy, and a significant proportion of patients has concurrent expression or rearrangements of MYC and BCL2. Bromodomain and extra-terminal (BET) proteins are transcriptional activators for multiple oncogenic processes in DLBCL, including MYC, BCL2, E2F, and toll-like receptor signaling. Results from monotherapy trials inhibiting BET by RG6146 (B)¹ or BCL2 by venetoclax (V)² demonstrated single agent activity in DLBCL pts (ORR: 15% and 18%, respectively). The combination B+V+rituximab (R) demonstrates enhanced activity in preclinical models of DLBCL. We report results of an ongoing phase 1b study in R/R DLBCL (NCT03255096).

<figure><img src="image_99.png" /><figcaption>Fig. 1: Summary of overall best response and duration on study (PET-CT Lugano Classification) *</figcaption></figure>
**Methods:** Pts with R/R DLBCL, including transformed follicular lymphoma (tFL), with at least 1 prior regimen which included an anti-CD20 agent were eligible. Other key criteria: ECOG ≤2, ineligible or R/R to ASCT, prior CAR-T cell or bispecific antibodies treatment was allowed. A 3 + 3 escalation design was used, initially B [(0.30, 0.45, or 0.65 mg/kg/d s.c. (14 d/3 wk cycle))] + V (400, 600, or 800 mg/d/3 wk cycle) to determine doublet maximum tolerated dose (MTD); R was added (375 mg/m2 x 3d cycle 1; then d1 cycle 2+) in later cohorts. Primary endpoint was safety [DLT, MTD, recommended dose (RD)] and secondary endpoints were PK, biomarker, and preliminary efficacy assessments (modified Lugano criteria; investigator assessed).

**Results:** 36 pts were treated from 8/2017 to 2/2019. Median age 68 (28-81) years, 17M:19F, stage IV 26 (72%), median prior regimens 3 (1-6), prior CAR-T or bispecifics 6 (17%). Baseline biomarker data (26 pts): COO GCB in 18/26 (69%); MYC+BCL2 wt disease (58%), 1 pt had MYC and 7 pts had BCL2 translocations.

**Safety:** Doublet MTD was determined as 0.65 mg/kg B + 600 mg V and triplet expansion is near completion to confirm 0.45 mg/kg B + 600 mg V + 375 mg/m2 R as MTD/RD. Pts received a median of 3 (1-11) cycles. Higher rates of Grade (G) 3/4 AEs (%): thrombocytopenia (+6.9), anemia (+11.2), neutropenia (+2.3) and diarrhea (+3.1) relative to V monotherapy were observed and expected. DLTs include G3 febrile neutropenia, G4 diarrhea and hypomagnesemia for B+V; and G3 hyperbilirubinemia, G4 diarrhea for B+V+R. PK: Data for B are similar to B monotherapy with approximately dose proportional increases in exposure with increasing dose and ~2-fold accumulation. Activity: ORR (28 evaluable pts) is 46%, with 25% CR; median DOR is 5 mo (0.5-11 mo) (Figure 1). Responses were seen in all cohorts and all molecular subtypes.

**Conclusions:** RG6146, venetoclax, and rituximab is a tolerable, highly active regimen [46% ORR (25% CR)] with durable responses in R/R DLBCL and tFL. These results suggest the regimen is a valuable treatment option for heavily-pretreated R/R DLBCL patients.

1. P. Caimi, ICML, abstr. 274, 2017

2. MS Davids, J Clin Oncol, 2017

**Keywords:** BCL2; bromodomains; diffuse large B-cell lymphoma (DLBCL).

**Disclosures:** Dickinson, M: Other Remuneration: (Speaker fees) Roche. Briones Mejjide, J: Employment Leadership Position: N/A; Consultant Advisory Role: Takeda, Jansen, Celgene, Gilead; Honoraria: Roche, Takeda, Celgene, Novartis, Gilead; Research Funding: Roche; Other Remuneration: (Travel) Roche, Takeda, Celgene, Jansen, Gilead. Herrera, A: Consultant Advisory Role: BMS, Genentech, Merck, Kite Pharma, Gillead, Adaptive Biotechnologies; Research Funding: Immune Design, AstraZeneca, Seattle Genetics. Ghosh, N: Consultant Advisory Role: Seattle Genetics, Pharmacyclics, Janssen, Gilead/Kite, AbbVie, BMS, TG Therapeutics, Celgene/Juno. Cordoba, R: Consultant Advisory Role: Servier, Kiowa, Janssen. Rutherford, S: Consultant Advisory Role: AstraZeneca, Celgene, Heron, Juno, Janssen, Karyopharm, Seattle Genetics, Verastem; Research Funding: Genentech. Advani, R: Consultant Advisory Role: AstraZeneca, Autolus, Bayer Healthcare Pharmaceuticals, Bristol Myers Squibb, Cell Medica, Roche, Genentech, Gilead, Juno, KitePharma, Kyowa, NanoString, Pharmacyclics, Seattle Genetics,

Spectrum, Sutro, Takeda; Research Funding: Institutional Research Funding For Trial. Bournazou, E: Employment Leadership Position: Hoffmann-La Roche; Stock Ownership: Hoffmann-La Roche. Labriola-Tompkins, E: Employment Leadership Position: Hoffmann-La Roche; Stock Ownership: Hoffmann-La Roche. Friess, T: Employment Leadership Position: Hoffmann-La Roche; Stock Ownership: Hoffmann-La Roche. Chesne, E: Employment Leadership Position: Hoffmann-La Roche; Stock Ownership: Hoffmann-La Roche. Brouwer-Visser, J: Employment Leadership Position: Hoffmann-La Roche; Stock Ownership: Hoffmann-La Roche. Lechner, K: Employment Leadership Position: Roche Diagnostics; Stock Ownership: Roche Diagnostics. Brennan, B: Employment Leadership Position: Hoffmann-La Roche. Nueesch, E: Employment Leadership Position: Hoffmann-La Roche; Stock Ownership: Hoffmann-La Roche. De Mario, M: Employment Leadership Position: Hoffmann-La Roche; Stock Ownership: Hoffmann-La Roche. Hutchings, M: Consultant Advisory Role: Takeda, Roche, Celgene; Honoraria: Takeda, Roche, Celgene, Janssen; Research Funding: Takeda, Roche, Novartis, Celgene.

126
POLATUZUMAB VEDOTIN (POLA) +
OBINUTUZUMAB (G) + LENALIDOMIDE
(LEN) IN PATIENTS (PTS) WITH
RELAPSED/REFRACTORY (R/R)
FOLLICULAR LYMPHOMA (FL): PHASE IB/II
INTERIM ANALYSIS

C. Diefenbach¹ | B. Kahl² | L. Banerjee³ |

A. McMillan⁴ | R. Ramchandren⁵ | F. Miall⁶ |

J. Briones⁷ | R. Cordoba⁸ | E. Gonzalez-Barca⁹ |

C. Panizo¹⁰ | J. Hirata¹¹ | N. Chang¹² |

L. Musick¹³ | P. Abrisqueta¹⁴

¹Department of Hematology/Oncology, Perlmutter Cancer Center at
NYU Langone Health, New York, NY, United States; ²Division of
Oncology, Washington University, St. Louis, MO, United States;
³Oncology Centre, Maidstone and Tonbridge Wells NHS Trust, Kent,
United Kingdom; ⁴Centre for Clinical Haematology, Nottingham
University Hospitals NHS Trust, Nottingham, United Kingdom; ⁵Division
of Oncology, University of Tennessee, Knoxville, TN, United States,
Barbara Ann Karmanos Cancer Institute, Detroit, MI, United States;
⁶Department of Haematology, University Hospitals of Leicester NHS
Trust, Leicester, United Kingdom; ⁷Department of Hematology, Hospital
Santa Creu i Sant Pau, Barcelona, Spain; ⁸Department of Hematology,
Fundacion Jimenez Diaz, Madrid, Spain; ⁹Haematology, Institutut Catala
D'Oncologia, Barcelona, Spain; ¹⁰Haemotology and Haemotherapy
Department, Clínica Universidad de Navarra, Madrid, Spain; ¹¹Production
Development Oncology, Genentech, Inc., South San Francisco, CA, United
States; ¹²Oncology, F. Hoffmann-La Roche Ltd, Mississauga, Canada;
¹³Clinical Sciences-Hematology, Genentech, Inc., South San Francisco,
CA, United States; ¹⁴Department of Hematology, Vall d'Hebron Institute
of Oncology (VHIO), Hospital Universitari Vall d'Hebron, Barcelona, Spain
**Introduction:** Pola-G-Len may enhance anti-tumor immune response in R/R FL. We report a pre-planned interim analysis of the safety/efficacy of induction and maintenance with Pola-G-Len in pts with R/R FL in a phase Ib/II study (NCT02600897).

**Methods:** Pts received induction treatment with 6x 28-day (D) cycles (C) of: G 1000mg IV (C1: D1, D8, D15; C2-6: D1); Pola 1.4mg/kg or 1.8mg/kg dose escalation (DE) or recommended phase 2 dose (RP2D; expansion) IV (D1); and Len 10-20mg (DE) or RP2D (expansion) PO (D1-21). Pts with complete response (CR)/partial response (PR)/stable disease (SD) at the end of induction (EOI) received G 1000mg (D1 every 2mo, for 24mo), and Len (10mg, D1-21 monthly, 12mo). Primary endpoints were C1 dose-limiting toxicities (DLTs), safety/tolerability, CR rate at EOI (modified Lugano criteria).

**Results** At the interim data cut-off (6 July 2018), 52 pts were enrolled: 9 discontinued the study (adverse events [AE], n=3; death due to PD, n=4; pt withdrawal, n=1; other, n=1). At baseline, the median pt age was 62 (range 32-87) years; 60% were male; 58% had FLIPI score 3-5; 79% had received ≥2 prior therapy lines; 50% were refractory to their last treatment; 17% had bulky disease (≥7cm). Two DLTs were reported in the cohort receiving Pola 1.8mg/kg + Len 10mg during the DE period (Gr 4 lipase/amylase elevation; asymptomatic, resolved with supportive care; Gr 3 thrombocytopenia leading to a delay in the initiation of cycle 2). Gr ≥3 AEs were experienced by 75% of pts: neutropenia (46%), thrombocytopenia (17%), anemia (12%) and infections (12%) were the most common AEs. Len dose reduction or interruption occurred in 31% and 52% of pts, respectively. One Gr 5 AE was reported (septic shock after PD in pt receiving subsequent therapy). The RP2D was determined as Pola 1.4mg/kg + Len 20mg. Preliminary efficacy data suggest high activity, with an independent review committee-assessed Modified Lugano response rate of 89% and a CR rate of 67% (Table). Median progression-free survival was not reached (median follow-up duration 8.95 mo in the efficacy-evaluable population).

**Conclusions** The safety profile of Pola-G-Len is consistent with known profiles of the individual drugs. Response rates at EOI with Pola-G-Len are promising, with high CR compared with available R/R FL treatments.

<table><caption>**TABLE 1** Responses at end of induction (efficacy-evaluable population; recommended phase II dose; N=18)</caption><thead><tr><th rowspan="2">Best overall response,<br>n (%)</th><th colspan="2">Modified<br>Lugano 2014</th><th colspan="2">Lugano 2014</th></tr><tr><th>INV</th><th>IRC</th><th>INV</th><th>IRC</th></tr></thead><tbody><tr><td>Objective response rate</td><td>16 (89)</td><td>16 (89)</td><td>16 (89)</td><td>16 (89)</td></tr><tr><td>CR</td><td>11 (61)<sup>1</sup></td><td>12 (67)<sup>2</sup></td><td>14 (78)</td><td>14 (78)</td></tr><tr><td>PR</td><td>5 (28)</td><td>4 (22)</td><td>2 (11)</td><td>2 (11)</td></tr><tr><td>SD</td><td>1 (6)</td><td>1 (6)</td><td>1 (6)</td><td>1 (6)</td></tr><tr><td>PD</td><td>0</td><td>0</td><td>0</td><td>0</td></tr><tr><td>Missing/unevaluable</td><td>1 (6)<sup>3</sup></td><td>1 (6)<sup>3</sup></td><td>1 (6)<sup>3</sup></td><td>1 (6)<sup>3</sup></td></tr></tbody></table>

**Acknowledgment:** Third-party editorial assistance, under the direction of authors was provided by Angela Rogers of Gardiner-Caldwell Communications, and was funded by F Hoffmann-La Roche.

© 2019 American Society of Clinical Oncology, Inc. Reused with permission. This abstract was accepted and previously presented at the 2019 ASCO Annual Meeting. All rights reserved.

**Keywords:** follicular lymphoma (FL); immunoconjugates; polatuzumab.

**Disclosures:** Diefenbach, C: Consultant Advisory Role: Seattle Genetics, Bayer, Bristol-Myers Squibb, Genentech/Roche, Merck; Stock Ownership: Gilead Sciences; Research Funding: Seattle Genetics, Genentech, Incyte, LAM Therapeutics, Merck, Bristol-Myers Squibb, Millennium, MEI Pharma.

Kahl, B: Consultant Advisory Role: Roche, Genentech, Celgene, AbbVie, Pharmaceutics, Acerta; Research Funding: Genentech, Acerta, BeiGene.

Banerjee, L: Other Remuneration: Novartis, Takeda, Gilead (travel, accommodation, expenses). McMillan, A: Honoraria: Roche, Celgene, Novartis, MSD, BMS, Sandoz; Research Funding: Pfizer; Other Remuneration: Roche, Celgene (speakers' bureau, and travel, accommodation and expenses). Ramchandren, R: Consultant Advisory Role: Pharmaceutics, Genentech, Celgene, BMS; Research Funding: Merck, Pharmaceutics, Janssen; Other Remuneration: CARIS (travel, accommodation and expenses).

Miall, F: Consultant Advisory Role: Takeda, Roche; Honoraria: Takeda, Roche; Other Remuneration: Takeda, Roche, Janssen (travel, accommodation and expenses). Briones, J: Consultant Advisory Role: Takeda, Nocartis, Celgene; Honoraria: Roche, Takeda, Novartis, Gilead; Research Funding: Roche; Other Remuneration: Roche, Celne, Janssen, Gilead (travel, accommodation and expenses). Cordoba, R: Consultant Advisory Role: Celgene, Janssen; Other Remuneration: Janssen, Roche, Servier (speakers' bureau); Janssen, Roche, Abbvie (travel, accommodation and expenses). Gonzalez-Barca, E: Consultant Advisory Role: Deltrion, Janssen, Gilead, Sandoz, Klowa; Other Remuneration: Janssen, AbbVie, Roche, Takeda (speakers' bureau); Janssen, AbbVie, Roche (travel, accommodation and expenses). Panizo, C: Consultant Advisory Role: Bristol-Myers Squibb, Kyowa Kirin; Other Remuneration: Roche Pharma, Janssen (speakers' bureau); Roche Pharma (travel, accommodation and expenses).

Hirata, J: Employment Leadership Position: Roche; Stock Ownership: Roche. Chang, N: Employment Leadership Position: Roche; Stock Ownership: Roche. Musick, L: Employment Leadership Position: Genentech, Inc.

127
THE PI3Kδ INHIBITOR ME-401 ± RITUXIMAB IN RELAPSED/REFRACTORY (R/R) FOLLICULAR LYMPHOMA (FL), CHRONIC LYMPHOCYTIC LEUKEMIA (CLL), AND SMALL LYMPHOCYTIC LYMPHOMA (SLL)

A.D. Zelenetz¹ | D. Jagadeesh² | V.P. Kenkre³ |

N.M. Reddy⁴ | A. Stathis⁵ | H.S. Salman⁶ |

A.S. Asch⁷ | J. Soumerai⁸ | H.S. Jhangiani⁹ |

A. Iasonos¹ | K. Patel¹⁰ | J. Carter¹ |

J. LLorin-Sangalang¹¹ | J.M. Pagel¹⁰

<footnote n="13">¹³ pts and ²² pts downgraded from CR to PR with Modified Lugano due to missing bone marrow biopsy; ³¹ pt had PR by CT (interim scan) but no PET at EOI performed before SCT.</footnote>

<footnote>Abbreviations: CR, complete response; EOI, end of induction; INV, investigator assessment; IRC, independent review committee assessment; PD, progressive disease; PR, partial response; SD, stable disease.</footnote>
¹Lymphoma, Memorial Sloane Kettering Cancer Center, New York City, United States; ²Hematology, Cleveland Clinic Taussig Cancer Institute, Cleveland, United States; ³Hematology, University of Wisconsin Medical Center, Madison, United States; ⁴Hematology, Vanderbilt University Ingram Cancer Center, Nashville, United States; ⁵Hematology, IOSI - Oncology Institute of Southern Switzerland, Bellinzona, Switzerland; ⁶Hematology, Stony Brook Medical Center, Stony Brook, United States; ⁷Hematology, University of Oklahoma Stephenson Cancer Center, Oklahoma, United States; ⁸Hematology, Massachusetts General Hospital, Boston, United States; ⁹Hematology/Oncology, Compassionate Care Cancer Center, Fountain Valley, United States; ¹⁰Hematology, Swedish Cancer Institute, Seattle, United States; ¹¹Clinical Development, MEI Pharma, San Diego, United States

**Background:** ME-401, a potent and selective oral PI3kδ inhibitor, is being evaluated in a Phase 1b study in patients (pts) with R/R B-cell malignancies (NCT02914938). 70 pts were treated as of January 2019 and we report here results in pts with FL and CLL/SLL.

**Methods:** Adult pts with ECOG performance status ≤2, no prior PI3K therapy, and progression of disease (POD) after ≥1 prior therapy were initially enrolled in a dose escalation phase (60-180 mg) then in 60 mg expansion cohorts as monotherapy or in combination with rituximab (375 mg/m² x 8 doses in 6 months). ME-401 was given initially on a daily continuous schedule (CS) until POD or unacceptable toxicity. Patients on CS were switched to an intermittent schedule (IS) on days 1-7 of a 28-day cycle in Cycle 3 (n = 20) or in Cycles ≥4 (n = 18) of CS. Toxicity on CS was managed by switch to IS and POD on IS was managed by switch to CS.

**Results:** 61 pts, 48 with FL and 13 with CLL/SLL received ME-401 alone (n = 48) or with rituximab (n = 13). Median age 65 yrs. (range: 38-81), median prior therapies 2 (range: 1-10), 33 pts had ≥2 prior therapies, and 25 FL pts were POD24. In CLL/SLL pts, IgVH was unmutated in 7, mutated in 2, and not evaluated in 4. 39 pts (64%) remain on therapy with a median follow-up of 12.3 months (range: 1.6-25.1) and 22 pts discontinued: 9 POD, 5 adverse events (AEs), 5 withdrew consent, and 3 were referred to stem cell transplant in CR. Delayed (i.e., Cycle >2) grade 3 immune related AEs (irAEs), primarily diarrhea/colitis and rash, were reported in 13/41 pts (31.7%) on CS and 2/20 pts (10%) who had switched to IS in Cycle 3, with irAEs noted 15 and 18 days after switch to IS. 6 pts with grade 3 irAEs had a drug holiday and corticosteroid therapy then resumed ME-401 on IS without recurrence of the irAE. Objective responses were achieved in 33/43 evaluable FL pts (77%) and 11/11 evaluable CLL/SLL pts (100%). In FL,

<table><caption>TABLE 1</caption><thead><tr><td>Dosing Schedule</td><td>No. of Pts</td><td>No. (%) of irAEs</td><td>No. Efficacy Evaluable Pts</td><td>No. (%) CR+PR</td></tr></thead><tbody><tr><td>CS or CS → IS in Cycles ≥4</td><td>41</td><td>13 (31.7%)</td><td>34</td><td>28 (82%)</td></tr><tr><td>CS → IS in Cycle 3</td><td>20</td><td>2 (10%)</td><td>20</td><td>16 (80%)</td></tr></tbody></table>

response rate was 77% with ME-401 alone (including 29% CR by Lugano criteria), 78% with ME-401 plus rituximab, 91% in POD24, and 75% in pts who had ≥2 prior therapies. Of 38 pts switched to IS, 33 (87%) remain on therapy (median: 14.5 months), 26 on IS and 7 who switched back to CS due to POD on IS, 3 pts discontinued due to persistent POD after switch to CS, and 2 pts withdrew.

**Conclusions:** ME-401 achieves a high rate of durable responses in R/R FL and CLL/SLL. IS appears to reduce the incidence of irAEs and maintain responses. POD on IS can be successfully retreated by reverting to CS. A global study is enrolling pts with R/R FL randomized to ME-401 by IS or CS after 2 cycles of CS, with switch to IS for irAEs and switch to CS if POD on IS (NCT03768505).

**Keywords:** chronic lymphocytic leukemia (CLL); follicular lymphoma (FL); PI3K/AKT/mTOR.

**Disclosures:** Zelenetz, A: Consultant Advisory Role: MEI Pharma, Amgen, Astra-Zeneca, Bayer, Celgene, DAVA oncology, Genentech/Roche, Gilead, Janssen, Karyopharm, Morphosys, Novartis, Pharmacyclics/AbbVie, Pfizer, Verastem. Reddy, N: Research Funding: AbbVie, BMS, Adaptive Biotechnologies, Gilead, Genentech. Stathis, A: Research Funding: Amgen, Bayer, Novartis, Pfizer, Roche, MEI Pharma. Soumerai, J: Consultant Advisory Role: Verastem; Research Funding: Roche/Genentech, BeiGene, TG Therapeutics. LLorin-Sangalang, J: Employment Leadership Position: MEI Pharma. Pagel, J: Consultant Advisory Role: Pharmacyclics, Gilead, Astra Zeneca.

128
INVESTIGATING SAFETY AND
PRELIMINARY EFFICACY OF AFM13 PLUS
PEMBROLIZUMAB IN PATIENTS WITH
RELAPSED/REFRACTORY HODGKIN
LYMPHOMA AFTER BRENTUXIMAB
VEDOTIN FAILURE

S.M. Ansell¹ | N.L. Bartlett² | R.W. Chen³ |

A. Herrera³ | E. Domingo-Domenech⁴ | A. Mehta⁵ |

A. Forero-Torres⁵ | R. Garcia-Sanz⁶ | P. Armand⁷ |

S. Devata⁸ | A. Rodriguez Izquierdo⁹ | I.S. Lossos¹⁰ |

C.B. Reeder¹¹ | T. Sher¹² | C. Choe-Juliak¹³ |

K. Prier¹⁴ | S.E. Schwarz¹⁴ | A. Strassz¹⁴ | L. Alland¹³ |

¹Hematology, Mayo Clinic, Rochester, United States; ²Medical Oncology, Siteman Cancer Center, Washington University School of Medicine, St. Louis, United States; ³Hematology & Hematopoietic Cell Transplantation, City of Hope, Duarte, United States; ⁴Clinical Hematology, Instituto Catalán de Oncología L'Hospitalet, Barcelona, Spain; ⁵Lymphoma Program, Hematology and Oncology, University of Alabama at Birmingham, Birmingham, United States; ⁶Hematology, Hospital Universitario de Salamanca, Salamanca, Spain; ⁷Medical oncology, Dana Farber Cancer Institute, Boston, United States; ⁸Division of Hematology/Oncology, University of Michigan Rogel Cancer Center, Ann Arbor, United States; ⁹Hematology, Hospital Universitario 12 de Octubre, Madrid, Spain; ¹⁰Hematology/oncology, University of Miami Sylvester
Comprehensive Cancer Center, Miami, United States; ¹¹Hematology, Mayo Clinic - Arizona, Phoenix, United States; ¹²Hematology, Mayo Clinic - Floria, Jacksonville, United States; ¹³Clinical Development, Affimed, Inc., New York, United States; ¹⁴Clinical Operations, Affimed GmbH, Heidelberg, Germany

**Background:** AFM13 is a bispecific, tetravalent NK cell-engaging antibody construct binding to CD30 on Hodgkin Lymphoma (HL) cells and CD16A on NK cells. <fnref n="1" /> Pembrolizumab is a PD-1 blocking antibody that induces high response rates in patients (pts) with relapsed or refractory HL (RRHL) <fnref n="2" />. AFM13 has shown clinical activity in pts with RRHL in a Phase 1 study ³. Preclinical data of the combination of AFM13 with PD-1 inhibition suggest synergism ⁴.

**Methods:** This Phase 1b dose escalation/extension study is evaluating the safety, tolerability and preliminary efficacy of the combination of AFM13 with pembrolizumab as salvage therapy after failure of standard therapies including brentuximab vedotin (BV) in pts with HL (NCT02665650). Pts receive escalating doses of AFM13 in combination with pembrolizumab following the classical 3+3 design. Response assessment is performed every 12 weeks by PET/CT according to the Lugano Classification ⁵. Data as of February 12, 2019 are presented.

**Results:** All thirty pts have been enrolled. The median age is 34 years (18-73), with a median of 4 (3-7) prior lines of therapy. All pts have failed standard treatments including BV and 43% had BV as their last therapy. Thirty seven percent have undergone prior autologous stem cell transplantation. Twelve pts were enrolled into the dose escalation cohorts and 18 into the Extension Cohort. All 30 pts completed the dose limiting toxicity (DLT) observation period. No DLTs occurred in Cohorts 1/2, one DLT occurred in Cohort 3 (missed ≥25% of AFM13 during the DLT period) and one DLT occurred in the Extension Cohort (Grade G4 infusion-related reaction (IRR)). Adverse Events were mainly G1/G2 and included IRRs (87%), rash (30%), nausea (23%), pyrexia (23%), and diarrhea (20%). G3/4 AEs included IRRs (13%), elevated aspartate aminotransferase (3%), gastritis (3%), hypotension (3%), nausea (3%), neutropenia (3%), and vomiting (3%). Included in the efficacy analysis were the best response from all 30 patients. The best overall response rate (ORR) and complete response (CR) rate for pts treated at the dose and schedule chosen for expansion (n=24; Cohort 3 and Extension Cohort) were 88% and 46% by independent assessment. Investigator assessment resulted in an ORR of 88% and CR rate of 42% for these pts. Estimated 6-month PFS rate at the highest treated dose level was 77%. Longer term follow up results will be presented at the meeting.

**Conclusions:** The combination of AFM13 and pembrolizumab is well-tolerated with most AEs mild to moderate in nature. The ORR of 88% compares favorably to the historical data of pembrolizumab in a similar RRHL population, with the CR rates of 42% and 46% by local and independent assessment, respectively, approximately doubling that of pembrolizumab (CR rates 22-25%) <fnref n="2" />.

## References

1) Reusch U., et al., *mAbs* 2014; 6(3): 728-39.

2) Chen et al., *J Clin Oncol* 2017; 35:2125-2132.

3) Rothe A., et al., *Blood*2015; 125(26): 4024-31. 4) Zhao X., et al., *J Clin Oncol* 2015; 33 (suppl; abstr 3050). 5) Cheson B.D., et al., *J Clin Oncol* 2014; 32(27): 3059-3067.

**Keywords:** CD30; Hodgkin lymphoma (HL).

**Disclosures:** Ansell, S: Research Funding: Affimed, BMS, Seattle Genetics, Trillium, Regeneron, Pfizer. Chen, R: Employment Leadership Position: Former employee of City of Hope. Herrera, A: Consultant Advisory Role: Bristol-Myers Squibb (BMS), Genentech, Merck, Seattle Genetics, Kite Pharma, Adaptive Biotechnologies; Research Funding: BMS, Genentech, Merck, Seattle Genetics, Pharmacyclics, Immune Design, Kite Pharma, and Gilead Sciences. Mehta, A: Consultant Advisory Role: Spectrum, Celgene, Kite, BMS, Astra Zeneca, Spectrum, Kyowa Kirin, Seattle Genetics; Research Funding: Incyte, Roche, Merck, BMS, Epizyme, Seattle Genetics, Kite, Forty Seven Inc, Takeda, Rhizen, Juno. Forero-Torres, A: Employment Leadership Position: Former employee of University of Alabama at Birmingham. Armand, P: Consultant Advisory Role: Merck, BMS, Pfizer, Affimed, Adaptive, Infinity; Research Funding: Merck, BMS, Affimed, Adaptive, Roche, Tensha, Otsuka, Sigma Tau. Choe-Juliak, C: Employment Leadership Position: Affimed, Inc. Prier, K: Employment Leadership Position: Affimed GmbH. Schwarz, S: Employment Leadership Position: Affimed GmbH. Strassz, A: Employment Leadership Position: Affimed GmbH. Alland, L: Employment Leadership Position: Affimed, Inc.

## 129
# TARGETING THE PERIPHERAL T-CELL LYMPHOMA (PTCL) EPIGENOME WITH ORAL 5-AZACYTIDINE AND ROMIDEPSIN: RESULTS AND CLINICAL-MOLECULAR CORRELATIONS FROM A PHASE 2 STUDY

L. Falchi<fnref n="1" /> | J.K. Lue<fnref n="1" /> | F. Montanari<fnref n="1" /> | E. Marchi<fnref n="1" /> |
J.E. Amengual<fnref n="1" /> | A. Sawas<fnref n="1" /> | C. Deng<fnref n="1" /> | K. Khan<fnref n="1" /> |
H.A. Kim<fnref n="1" /> | A. Rada<fnref n="1" /> | M. Malanga<fnref n="1" /> |
M.F. Francescone<fnref n="1" /> | C.R. Soderquist<fnref n="1" /> | D.C. Park<fnref n="1" /> |
G. Bhagat<fnref n="1" /> | L. Sokol<fnref n="2" /> | A.R. Shustov³ | O.A. O'Connor<fnref n="1" />

**Introduction:** PTCL exhibit pervasive dysfunction of epigenetic operations. This may be a targetable vulnerability, as demonstrated by the single-agent activity of histone deacetylase inhibitors (HDACi) and hypomethylating agents (HMA). We previously showed marked synergism between HDACi and HMA in T-cell lymphoma lines, accompanied by the modulation of >900 unique genes with the combination, but not the single agents. In a recently completed phase-1 study we observed encouraging activity of combined oral 5-azacytidine (AZA)

<footnote n="1">¹Medicine, Columbia University Medical Center, New York, United States;</footnote>

<footnote n="2">²Malignant Hematology, Moffitt Cancer Center/University of South Florida, Tampa, United States; ³Medicine, University of Washington School of Medicine, Seattle, United States</footnote>
and romidepsin (ROMI) in T-cell lymphoma patients. Here, we report the first analysis of the phase-2 portion of that study.

**Methods:** Patients with newly diagnosed (ND) or relapsed/refractory (R/R) PTCL were eligible for enrollment. The recommended phase-2 dose from the phase-1 trial was AZA 300 mg daily days 1-14 and ROMI 14 mg/ms days 8, 15, 22 every 35 days. The primary objective was overall response rate (ORR). Other endpoints were progression-free survival (PFS) and duration of response (DOR). We performed targeted next-generation sequencing (NGS) of pre-treatment tumor samples to correlate epigenetic gene mutations and response.

**Results:** Among 25 enrolled patients the median age was 63 years [42-88] and the M:F ratio was 14:11. 11 patients were ND and 14 were R/R, with a median of 2 prior therapies [1-6], 17 patients had AITL or PTCL-TFH, 3 PTCL-NOS, and 4 other subtypes (1 each of ALCL, ATLL, EATL, and ENKTL).

19 patients are evaluable for response and 5 are pending evaluation (complete data will be presented). The ORR was 68% (13/19), including 42% complete responses (CR) (8/19). Among 8 evaluable ND patients the ORR and CR were 75% and 37%, respectively, while among 11 R/R patients these were 64% and 45%, respectively. Notably, among 11 evaluable patients with AITL (9) or PTCL-TFH (2), 10 responded, and 6 achieved a CR.

23 patients are evaluable for toxicity. The most frequent hematologic G3-4 AE were thrombocytopenia (39%) and neutropenia (39%). The most frequent non-hematologic G3-4 AE included lung infection (17%) and febrile neutropenia (13%). Other common G1-2 toxicities included anemia, diarrhea, fatigue, nausea, and vomiting. No patients discontinued therapy due to AE. At a median follow-up of 5.8 months [0.3-23.1], the median DOR has not been reached (1.8-20.0+ months) and the median PFS for the entire population, ND and R/R patients is 7.9 months, 7.9 months, and not reached, respectively. Two patients have died, one due to progressive disease, one due to unknown cause.

Pre-treatment tumor samples are available for 17 patients, 13 of whom are evaluable for response: all patients had at least one mutation in an epigenetic gene. Importantly, 9/10 patients with a TET2 mutation responded, whereas only 1 of 3 patients with wild-type TET2 responded.

**Conclusions:** The AZA-ROMI combination is well tolerated and highly active in PTCL patients, particularly AITL or PTCL-TFH. TET2 mutations may portend a higher likelihood of response. Sequencing data from the entire study population will be presented (NCT01998035).

**Keywords:** epigenetics; peripheral T-cell lymphomas (PTCL); romidepsin (RD).

**Disclosures:** Amengual, J: Research Funding: Appia Pharmaceuticals.

Sokol, L: Honoraria: Celgene, Spectrum Pharmaceuticals, Seattle Genetics. Shustov, A: Honoraria: Portola Pharmaceuticals, Kyowa-Hakko-Kirin; Research Funding: Spectrum Pharmaceuticals.

O'Connor, O: Honoraria: Celgene; Research Funding: Celgene.

FOCUS ON... SESSION: INDOLENT NON-FOLLICULAR LYMPHOMA

130
EARLY PROGRESSION OF DISEASE (POD24)
PREDICTS SHORTER SURVIVAL IN MALT
LYMPHOMA PATIENTS RECEIVING
SYSTEMIC TREATMENT

A. Conconi<fnref n="1" /> | C. Thieblemont<fnref n="2" /> | L. Cascione<fnref n="3" /> |

V. Torri⁴ | B. Kiesewetter⁵ | G. Margiotta-Casaluci⁶ |

G. Gaidano⁶ | M. Raderer⁵ | F. Cavalli<fnref n="3" /> |

A. Lopez Guillermo⁷ | P.W. Johnson⁸ | E. Zucca⁹

**Introduction.** Progression of disease within two years from the start of therapy (POD24) is linked with poor outcome in follicular lymphoma who received first-line systemic therapy<fnref n="1" />. In the present study, we sought to understand whether early progression after first-line treatment is affecting overall survival (OS) also in extranodal marginal zone B-cell lymphomas of MALT type (EMZL).

**Methods.** We analyzed the dataset of the IELSG19 clinical trial<fnref n="2" /> (training set) to determine whether POD24 is associated with inferior OS. The study population included 401 EMZL patients (131 randomly assigned to chlorambucil treatment, 138 to rituximab and 132 to chlorambucil plus rituximab). Reproducibility was analyzed in an independent validation set (generated from the larger validation cohort of the MALT-IPI study<fnref n="3" />) which comprised 287 patients with adequate treatment and follow-up data, who received systemic treatment (chemotherapy, immunotherapy or both). In both, training and validation sets, we excluded from the analysis patients who died without progression within 24 months and those who were lost to follow-up without progression within 24 months from treatment start. Overall survival was calculated from disease progression in patients with POD24 and from 24 months after the start of treatment in those without POD24 (reference group).

**Results.** POD24 was observed in 69 of 401 patients of the IELSG19 study. The reference group comprises 315 patients with no relapse or death during the first 24 months since 17 patients were excluded

<footnote n="1">¹Division of Hematology, Ospedale degli Infermi, Ponderano, Italy;</footnote>

<footnote n="2">²Hemato-Oncology Department, Saint Louis Hospital, Paris, France;</footnote>

<footnote n="3">³IOR, Institute of Oncology Research, Bellinzona, Switzerland; ⁴Clinical Research Methodology Laboratory, IRCCS-Mario Negri Institute, Milan, Italy; ⁵Division of Oncology, Department of Internal Medicine I, Medical University of Vienna, Vienna, Austria; ⁶Division of Hematology, Department of Translational Medicine, University of Eastern Piedmont, Novara, Italy; ⁷Department of Hematology, Hospital Clinic, Barcelona, Spain; ⁸Cancer Research UK Center, Southampton General Hospital, Southampton, United Kingdom; ⁹Division of Medical Oncology, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland</footnote>
Testing set

<figure><img src="image_100.png" /></figure>

Validation set

<figure><img src="image_101.png" /></figure>

from the analysis (8 dead without POD within 24 months and 9 followed up for less than 24 months from treatment start). For the 69 patients (18%) with early POD, median age was 62 years, 32 patients were male and 26 had gastric localization. The 10-year OS rate was 64% in the POD24 group and 85% in the reference group (HR= 2.42, 95%CI, 1.35-4.35; log-rank P=0.002). Patients in the early-POD group were more likely to have high-risk MALT-IPI scores than those in the reference group (P=0.013). The prognostic impact of POD24 was confirmed in the validation set, in which POD24 was observed in 64 patients out of 224 evaluable patients (63 patients were excluded: 9 dead without POD within 24 months and 54 followed up for less than 24 months from treatment start) with 10-year OS rate of 48% in the POD24 group and 71% in the reference group (HR of 2.15, 95% CI, 1.19 to 3.90; log-rank P=0.009).

**Conclusions.** In patients with EMZL who received front-line systemic treatment, POD24 is associated with poorer survival and may represent a useful endpoint in future prospective clinical trials.

**Keywords:** extranodal lymphomas; extranodal marginal zone lymphoma of MALT type; prognostic indices.

131
INTRALESIONAL RITUXIMAB
SUPPLEMENTED WITH AUTOLOGOUS
SERUM IN RELAPSED CD20+ INDOLENT
LYMPHOMAS OF THE CONJUNCTIVA:
ACTIVITY AND SAFETY RESULTS OF THE
"IRIS" TRIAL

A.J. Ferreri<fnref n="1" /> | M. Sassone<fnref n="1" /> | E. Miserocchi<fnref n="2" /> |

S. Govi<fnref n="1" /> | C. Cecchetti<fnref n="1" /> | M.E. Corti<fnref n="3" /> | T. Calimeri<fnref n="1" /> |

S. Perrone<fnref n="1" /> | S. Mappa<fnref n="1" /> | M. Ponzoni⁴ | G. Modorati<fnref n="2" />

¹Lymphoma Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy;

²Ophthalmology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy;

³Pharmacy Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy;

⁴Pathology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy

**Background:** Most lymphomas primarily arising in the conjunctiva exhibit indolent behavior, with rare cases of systemic dissemination and symptomatic disease. Conventional chemo-, radio- and immunotherapy are associated with good disease control rates; however, the excellent prognosis of this lymphoma seems to suggest that less invasive and safer therapies should be preferred. Intravenous rituximab is well tolerated, but responses are usually short lived. Topic and intralesional therapies may play a role in the management of conjunctival lymphomas, but experience is limited to a few pts treated with intralesional interferon. Herein, we report a monoinstitutional phase II trial addressing safety and activity of intralesional rituximab supplemented by autologous serum in pts with CD20+ indolent lymphomas of the conjunctiva (NCT01514344 - IRIS trial).

**Methods:** Adults with relapsed/refractory CD20+ indolent lymphoma (MZL, FL, SLL, lymphoplasmacytic lymphoma) limited to the conjunctiva (mono- or bilateral disease), and measurable disease were registered and treated with intralesional injections of 10-20 mg of undiluted rituximab (1-2 ml) combined with local anesthetic. Pts received four weekly doses followed by six monthly injections. Toxicity was assessed before each rituximab dose, and objective response was assessed after weekly doses and at the end of the therapeutic program by photographs of the lesions. 500 microL of autologous serum were added to rituximab in pts who did not achieve at least partial response (PR). Safety was the primary endpoint; response rate and antitumor effect of the addition of autologous serum were secondary endpoints.

**Results:** 20 pts (median age 63 - range 30-81; 12 females) were registered; all pts had MZL, 4 pts had HBV/HCV infection, no pt had increased LDH serum levels. Treatment tolerability was excellent: there were no interruptions or delay due to toxicity; only 3 pts experienced mild local effects like edema and bleeding. 11 pts achieved tumor regression after the 4 weekly doses, whereas 9 pts required autologous serum. Response at the end of the whole treatment was complete in 10 pts and partial in 2, with an ORR of 63% (95%CI: 42-84%). At a median follow-up of 3 years (range 7-73), 12 pts remain relapse-free; relapse occurred in the contralateral eye in 2 pts, with a 3-year local disease control rate of 63 ±11%, and a 3-year PFS of 60 ±12%. Interestingly, 3 failed pts were retreated with intralesional rituximab and autologous serum achieving a further response that lasted 12, 25+ and 32+ months, respectively. All pts are alive.

**Conclusions:** Intralesional rituximab is a safe and active treatment in pts with conjunctival indolent lymphoma. The addition of autologous serum is associated with improved response in some cases.

<footnote n="1">¹ Casulo C, et al. J Clin Oncol. 2015; 33:2516-2522.</footnote>

<footnote n="2">² Zucca E, et al. J Clin Oncol. 2017; 35:1905-1912.</footnote>

<footnote n="3">³ Thieblemont C, et al. Blood. 2017; 130:1409-1417.</footnote>
Retreatment of local relapses can result in a second long-lasting response.

**Keywords:** CD20; extranodal marginal zone lymphoma of MALT type; rituximab.

132
MULTI-OMICS LANDSCAPE OF SPLENIC
MARGINAL ZONE LYMPHOMA (SMZL) -
INTERIM ANALYSIS OF IELSG46 STUDY

A. Bruscaggin¹ | M. Mollejo² | G. Tapia³ |
M. Gomes da Silva⁴ | U. Novak⁵ | S. Dietrich⁶ |
M. Ponzoni⁷ | A. Rambaldi⁸ | P. Corradini⁹ |
U. Vitolo¹⁰ | M. Merli¹¹ | A. Tzankov¹² |
S. Cogliatti¹³ | C. Montalban¹⁴ | R. Marasca¹⁵ |
L. de Leval¹⁶ | C. Visco¹⁷ | M.J. Baptista¹⁸ |
T. Tousseyn¹⁹ | F. Facchetti²⁰ | M. Paulli²¹ |
L. Mazzucchelli²² | S. Bea²³ | D. Oscier²⁴ |
P. Zinzani²⁵ | G. Bhagat²⁶ | G. Inghirami²⁷ |
G. Gaidano²⁸ | A. Traverse-Glehen²⁹ |
C. Thieblemont³⁰ | M.A. Piris³¹ | F. Cavalli³² |
L. Arcaini³³ | E. Zucca³⁴ | D. Rossi¹

¹Experimental Hematology, Institute of Oncology Research, Bellinzona, Switzerland; ²Division of Pathology, Hospital Virgen de la Salud, Toledo, Spain; ³Division of Pathology, Universitat Autònoma de Barcelona, Barcelona, Spain; ⁴Department of Hematology, Portuguese Institute of Oncology, Lisbon, Portugal; ⁵Department of Medical Oncology, University Cancer Center, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland; ⁶Division of Hematology, National Center for Tumor Diseases, Heidelberg, Germany; ⁷Division of Pathology, San Raffaele Hospital, Milan, Italy; ⁸Division of Hematology, ASST Papa Giovanni XXIII, Bergamo, Italy; ⁹Department of Hematology, Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Milan, Italy; ¹⁰Department of Oncology, AOU Città della Salute e della Scienza di Torino, Turin, Italy; ¹¹Division of Hematology, Ospedale di Circolo e Fondazione Macchi, Varese, Italy; ¹²Department of Medical Genetics and Pathology, University Hospital Basel, Basel, Switzerland; ¹³Division of Pathology, Kantonsspital St. Gallen, St. Gallen, Switzerland; ¹⁴Division of Hematology, MD Anderson Cancer Center, Madrid, Spain; ¹⁵Division of Hematology, Università di Modena e Reggio Emilia, Modena, Italy; ¹⁶Institute of Pathology, Lausanne University Hospital, Lausanne, Switzerland; ¹⁷Division of Hematology, Ospedale San Bortolo, Vicenza, Italy; ¹⁸Division of Hematology, Josep Carreras Leukaemia Research Institute, Barcelona, Spain; ¹⁹Division of Pathology, Katholieke Universiteit Leuven, Leuven, Belgium; ²⁰Medicina Molecolare e Traslazionale, Spedali Civili, Brescia, Italy; ²¹Division of Pathology, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy; ²²Division of Pathology, Istituto Cantonale di Patologia, Locarno, Switzerland; ²³Division of Pathology, Hospital Clinic de Barcelona, IDIBAPS, Barcelona, Spain; ²⁴Division of Hematology, Royal Bournemouth Hospital, Bournemouth, United Kingdom; ²⁵Division of Hematology, Policlinico Sant'Orsola, Bologna, Italy; ²⁶Department of Pathology & Cell

Biology, Columbia University Medical Center, New York, United States; ²⁷Division of Pathology, Weill Cornell Medical College, New York, United States; ²⁸Department of Translational Medicine, University of Eastern Piedmont, Novara, Italy; ²⁹Division of Pathology, Centre Hospitalier Lyon Sud, Pierre-Bénite, France; ³⁰Division of Hematology, Saint Louis Hospital, Paris, France; ³¹Division of Pathology, Fundacion Jimenez Diaz, Madrid, Spain; ³²Division of Oncology, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland; ³³Division of Hematology, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy; ³⁴Lymphomas Unit, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland

*EZ and DR equally contributed

**Introduction:** Splenic marginal zone lymphoma (SMZL) is heteroge-
neous at the morphological, biological and clinical level, suggesting the
existence of includes still unveiled subtypes. According to the 2016
WHO classification, discovery of new entities or subtypes within het-
erogeneous tumors should be based using a multiparametric
approach, encompassing tumor histopathology, genetics,
immunophenotype and clinical course.

**Methods:** The IELSG46 study (NCT02945319) is the largest repository of clinical data and spleen samples from SMZL patients, and has the statistical power to resolve tumor subgroups within this lymphoma. Mutations were identified by CAPP-seq of tumor genomic DNA, copy number aberrations (CNA) by sequencing reads-based GATK4-CNV, IGHV rearrangements by LymphoTrack®, gene expression profiling (GEP) by mRNA-seq.

**Results:** Overall, the genetic-immunogenetic profile of the study cohort (n=382) was consistent with prior unselected SMZL series, reported by us in previous findings by our and other groups. Genes recurrently mutated in >10% SMZL were KLF2, NOTCH2, KMT2D, TNFAIP3 and NOTCH1. Deletion 7q occurred in 24% SMZL and IGHV1-2\*04 was used in 30% SMZL. Machine learning approaches applied to multiple layers of "big" data led to the discovery of unexpected molecular clusters (MC) in SMZL, each associated with distinct clinical outcome (Fig.1A). MC1 (NF-κB pathway) and MC2 (NOTCH pathway), driven by KLF2 and NOTCH2 mutations respectively, were enriched in IGHV1-2\*04 gene usage and 7q deletion. MC3 was defined by epigenetic mutated genes and was enriched in KMT2D mutations. MC4 was enriched in TP53 and ATM mutations, and in 17p deletions. SMZL patients showed an overall 26% decrease in survival at 15 years compared to the matched general population. Among molecular clusters, only MC1 and MC2 showed a lower relative survival compared to the general population, indicating a significant impact of the disease on MC1 and MC2 patients' life expectancy. Transcriptome profiling of 55 tumor samples led to the discovery of 3 molecular phenotypes (MP) in SMZL. MP1 showed an inflammatory response signature, MP2 a B-cell receptor signaling signature, and MP3 that lacked of both these signatures (Fig.1B).

**Conclusions:** Genetic analysis of a large cohort of SMZLs cases identified four molecular subtypes characterized by unique deregulated genetic pathways, clinical outcome and potentially a molecular phenotype. These results can provide the basis for proposing the
<figure><img src="image_102.png" /><figcaption>Fig. 1</figcaption></figure>

classification of SMZL into provisional molecular subtypes, that may lead to a conceptual edifice for developing precision therapies for SMZL patients.

**Keywords:** gene expression profile (GEP); molecular genetics; splenic marginal zone lymphoma (SMZL).

133
UMBRALISIB MONOTHERAPY
DEMONSTRATES EFFICACY AND SAFETY
IN PATIENTS WITH
RELAPSED/REFRACTORY MARGINAL
ZONE LYMPHOMA: A MULTICENTER,
OPEN-LABEL, REGISTRATION DIRECTED
PHASE 2 STUDY

P. Zinzani<fnref n="1" /> | F. Samaniego² | W. Jurczak³ |

E. Lech-Maranda⁴ | N. Ghosh⁵ | B. Anz⁶ |

P. Patten⁷ | J. Reeves⁸ | L.A. Leslie⁹ |

P. Smolewski¹⁰ | J.C. Chavez¹¹ | L. Scarfo¹² |

E. Derenzini¹³ | J.M. Burke¹⁴ | J. Sharman¹⁵ |

K. Kolibaba¹⁶ | O.A. O'Connor¹⁷ | C.Y. Cheah¹⁸ |

H.P. Miskin¹⁹ | P. Sportelli¹⁹ | M.S. Weiss¹⁹ |

N.H. Fowler²

<footnote n="1">¹Institute of Hematology, "L. e A. Seragnoli" University of Bologna, Bologna, Italy; ²Department of Lymphoma/ Myeloma, MD Anderson Cancer Center, Houston, United States; ³Department of Hematology, Jagiellonian University, Krakow, Poland; ⁴Department of Hematology, Institute of Hematology and Transfusion Medicine, Warsaw, Poland; ⁵Department of Hematologic Oncology and Blood Disorders, Levine</footnote>
Cancer Center, Charlotte, United States; ⁶Tennessee Oncology, Sarah Cannon Research Institute, Chattanooga, United States; ⁷Department of Hematology, Kings Hospital NHS Foundation Trust, London, United Kingdom; ⁸Florida Cancer Specialists, Sarah Cannon Research Institute, Fort Myers, United States; ⁹John Theurer Cancer Center, Hackensack University Medical Center, Hackensack, United States; ¹⁰Department of Hematology, Copernicus Memorial Hospital, Lodz, Poland; ¹¹Department of Hematology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, United States; ¹²IRCCS Ospedale San Raffaele, Università Vita-Salute San Raffaele, Milan, Italy; ¹³Department of Hematology, European Institute of Oncology, Milan, Italy; ¹⁴Rocky Mountain Cancer Centers, US Oncology, Aurora, United States; ¹⁵Willamette Valley Cancer Institute, US Oncology, Eugene, United States; ¹⁶Compass Oncology, US Oncology, Vancouver, United States; ¹⁷Center for Lymphoid Malignancies, Columbia University Medical Center, New York, United States; ¹⁸Department of Hematology, Sir Charles Gairdner Hospital, Perth, Australia; ¹⁹Drug Development, TG Therapeutics, New York, United States

**Introduction:** Rituximab (RTX) alone or in combination with chemotherapy has substantially improved treatment outcomes for patients (pts) with marginal zone lymphoma (MZL), but relapse is common and not all pts are acceptable candidates for, or respond to, current salvage therapies. Umbralisib is a novel, next-generation PI3K-delta inhibitor with unique inhibition of casein kinase-1ε (CK1ε) and, compared to earlier generation PI3K-delta inhibitors, exhibits a differentiated tolerability profile with reduced rates of immune-mediated toxicity (Burris et al, 2018). This registration-directed study evaluates the efficacy and safety of umbralisib in pts with relapsed/refractory (R/R) MZL.

**Methods:** Pts had histologically confirmed MZL, ECOG PS ≤2, and had previously received ≥1 prior therapy including at least one CD20 monoclonal antibody (mAb)-containing regimen. All pts received umbralisib 800 mg orally once daily until progression or unacceptable toxicity. The primary study endpoint was overall response rate (ORR) as assessed by an independent review committee (IRC) according to 2007 IWG criteria. ORR by investigator assessment is reported here, and ORR by IRC is forthcoming. Secondary endpoints included duration of response (DOR), progression-free survival (PFS), and safety.

**Results:** Sixty-nine pts were enrolled; we report on the first 38 who are eligible for at least 6 months (mos) of follow-up as of the data cutoff date. Disease status for the 38 pts: extranodal (n=23), nodal (n=8), and splenic (n=7). Median age was 67 years (range, 34-81). Median number of prior systemic therapies was 2 (range, 1-5). Seven pts (18%) had received monotherapy RTX only, and 26 (68%) had received at least one CD20 mAb-containing chemoimmunotherapy. As of the cut-off date, the median follow-up was 9.6 mos. Per investigator assessment, ORR was 55% (4 CRs and 17 PRs), 29% of pts (n=11) had stable disease (SD) of which 6 of these SD pts remain on study with durations ranging from 7-12+ mos. The clinical benefit rate (CR+PR+SD) was 84%, and 91% of pts with at least 1 post-baseline assessment experienced tumor reductions. The median time to initial response was 2.7 mos, while the median DOR was not reached (95% CI: 8.4-not reached). The 12-month PFS was 71%. The most common (≥20%) adverse events (AE) of any grade included: diarrhea

(45%), nausea (29%), fatigue (26%), headache (26%), cough (24%), and decreased appetite (21%). The most common Grade 3/4 events were neutropenia (8%), febrile neutropenia (5%), and diarrhea (5%). As of the cutoff date, 16 pts discontinued treatment (PD: 18%; AEs: 8%; pt decision: 8%; physician decision: 8%) and 58% continue treatment.

**Conclusions:** PI3K-delta inhibition with single-agent umbralisib is active and well tolerated in pts with R/R MZL, achieving durable responses with chemotherapy-free therapy.

**Keywords:** marginal zone lymphoma (MZL); non-Hodgkin lymphoma (NHL); PI3K/AKT/mTOR.

**Disclosures:** Zinzani, P: Consultant Advisory Role: TG Therapeutics, Bayer, BMS, Merck, Gilead, SERVIER, Roche, Celltrion, Pfizer, Takeda, Verastem, Celgene; Honoraria: TG Therapeutics, BMS, Merck, Gilead, SERVIER, MSD, Roche, Celltrion, Pfizer, Verastem, Celgene, Janssen. Samaniego, F: Research Funding: ADC Therapeutics. Jurczak, W: Consultant Advisory Role: Sandoz Novartis, Janssen, European Medicines Agency, AstraZeneca, Acerta, Gilead; Research Funding: Pharmacodynamics, MorphoSys, Merck, Nordic Nanovector, Janssen, Epizyme, Celgene, Beigene, Bayer, Afimed, Acerta, Gilead, Servier, Roche, TG Therapeutics. Lech-Maranda, E: Consultant Advisory Role: Roche, Jansen-Cilag, Novartis, BMS, Amgen. Patten, P: Consultant Advisory Role: Gilead; Honoraria: L Hoffman La Roche, Gilead, AbbVie Inc, Janssen; Research Funding: L Hoffman La Roche, Gilead. Derenzini, E: Research Funding: TG Therapeutics. Burke, J: Consultant Advisory Role: Gilead, Genentech, Celgene, AbbVie, Bayer, Seattle Genetics, Tempus Labs. Sharman, J: Consultant Advisory Role: Acerta, Pharmacodynamics, Genentech, TG Therapeutics, AbbVie; Honoraria: Genentech; Research Funding: Acerta, Pharmacodynamics, Pfizer, TG Therapeutics, AbbVie. Kolibaba, K: Consultant Advisory Role: Gilead; Honoraria: TG Therapeutics; Research Funding: Janssen. Gilead, Pharmacodynamics, Celgene, Novartis, Seattle Genetics, TG Therapeutics, Acerta, Genentech, Cell Therapeutics. O'Connor, O: Research Funding: Celgene, ADC Therapeutics, Seattle Genetics. Miskin, H: Employment Leadership Position: TG Therapeutics. Sportelli, P: Employment Leadership Position: TG Therapeutics. Weiss, M: Employment Leadership Position: TG Therapeutics. Fowler, N: Consultant Advisory Role: Pharmacodynamics, Janssen; Research Funding: Pharmacodynamics, Janssen.

<footnote n="1">¹Bing Center for Waldenstrom Macroglobulinemia, Dana-Farber Cancer Institute, Boston, United States; ²Hematology, Rabin Medical Center, Petah Tikva, Israel; ³Hematology and Oncology, Mayo Clinic, Rochester, United States; ⁴Hematology, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy; ⁵Comprehensive Cancer Center, University Hospital Ulm,</footnote>
<figure><img src="image_103.png" /></figure>

Ulm, Germany; ⁶Hematology, Churchill Hospital, Oxford, United Kingdom;

⁷Malignant Hematology, Moffitt Cancer Institute, Tampa, United States;

⁸Hematology, Middlemore Hospital, Auckland, New Zealand;

⁹Hematology and Oncology, Memorial Sloan Kettering Cancer Center, New York, United States; ¹⁰Hematology, North Shore Hospital, Auckland, New Zealand; ¹¹Hematology, Canberra Hospital, Canberra, Australia;

¹²Hematology, Peter MacCallum Cancer Centre, Melbourne, Australia;

¹³Hematology, Niguarda Hospital, Milan, Italy; ¹⁴Center for CNS Lymphoma, Dana-Farber Cancer Institute, Boston, United States

**Background:** The oral BTK inhibitor ibrutinib is the only approved therapy for patients with symptomatic Waldenström macroglobulinaemia (WM). Bing-Neel syndrome (BNS) is a rare complication of WM that results from infiltration of malignant lymphoplasmacytic cells into the central nervous system (CNS) causing neurological deficits. Treatment options in patients with BNS are limited to agents with CNS penetration. Furthermore, patients with BNS are excluded from WM clinical trials.

**Methods:** We performed a multicenter retrospective study evaluating the efficacy of ibrutinib in patients with BNS. The diagnosis of BNS was established in patients with a clinicopathological diagnosis of WM by radiological and/or cytological evidence of CNS involvement by WM. Ibrutinib was given orally at doses of 420-560 mg PO once daily until disease progression or intolerable toxicity. Response was assessed using criteria from the 8th International Workshop for WM. Events were defined as disease progression, death from disease progression and stopping ibrutinib due to ibrutinib-related toxicity. The time to event was estimated using the Kaplan-Meier method. Adverse events were assessed according to the Common Toxicity Criteria version 4.03.

**Results:** Twenty-eight patients were included in our study. The median age at BNS diagnosis was 65 years. Ibrutinib was the first line of treatment for BNS in 39% of patients. Ibrutinib was administered orally at a dose of 560 and 420 mg once daily in 46% and 54% of patients, respectively. Symptomatic and radiologic improvements were seen in 85% and 60% of patients within 3 months of therapy, respectively. At best response, 85% of patients had improvement or resolution of BNS

symptoms, 83% had improvement or resolution of radiologic abnormalities, and 47% had cleared the disease in the cerebrospinal fluid (CSF). With a median follow-up time of 20 months, 12 patients have stopped ibrutinib. Of these, 8 were considered related events; 3 patients had disease progression, 3 patients had ibrutinib-related toxicity and 2 patients died of disease progression. The other 4 unrelated events included death due to unrelated causes (n=2), myelodysplasia (n=1) and receiving allogeneic transplantation (n=1). The median EFS was not yet reached. The 3-year EFS rate was 69% (95% CI 48-84%) (Figure). Thirteen patients (45%) had a reported adverse event. Grade 4 adverse events included neutropenia (n=1). Grade 3 adverse events included pneumonia (n=2), muscle cramps (n=1), bleeding (n=1), atrial fibrillation (n=1), and ventricular tachycardia (n=1).

**Conclusion:** Ibrutinib monotherapy can induce durable responses with acceptable toxicity in patients with BNS. Despite symptomatic and radiological improvements in the majority of patients, half of the patients can have persistence of disease in the CSF, and this should not represent treatment failure.

**Keywords:** BTK inhibitors; ibrutinib; Waldenström's macroglobulinaemia (WM).

**Disclosures:** Castillo, J: Consultant Advisory Role: Beigene, Janssen, Roche; Research Funding: Abbvie, Beigene, Janssen, Pharmacyclics, TG Therapeutics.

135
# IBRUTINIB MONOTHERAPY PRODUCES LONG-TERM DISEASE CONTROL IN PREVIOUSLY TREATED WALDENSTROM'S MACROGLOBULINEMIA. FINAL REPORT OF THE PIVOTAL TRIAL (NCT01614821).

S.P. Treon<fnref n="1" /> | K. Meid<fnref n="1" /> | J. Gustine<fnref n="1" /> | G. Yang<fnref n="1" /> |

L. Xu<fnref n="1" /> | C.J. Patterson<fnref n="1" /> | I. Ghobrial<fnref n="1" /> |

J.P. Laubach<fnref n="1" /> | Z.R. Hunter<fnref n="1" /> | T. Dubeau<fnref n="1" /> |

L. Palomba² | R. Advani<fnref n="3" /> | J.J. Castillo<fnref n="1" />

MYD88 mutations are present in ≥95% of WM patients and trigger malignant cell survival through BTK and HCK, both ibrutinib targets. CXCR4 mutations are found in 30-40% of WM patients and confer in vitro drug resistance. We therefore investigated the activity of ibrutinib in previously treated WM patients. The initial findings showed that ibrutinib was highly active, and supported FDA and EMA drug approval in WM (Treon et al, NEJM 2015). Herein, we provide a long-term follow-up of this study that included impact of MYD88 and CXCR4 mutation status on long-term progression-free survival. Sixty-three symptomatic WM patients with a median of 2 (range 1-9) prior therapies, including 40% refractory were enrolled. Ibrutinib was

<footnote n="1">¹Bing Center for Waldenstrom's Macroglobulinemia, Dana Farber Cancer Institute, Boston, MA, United States; ²Hematology Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, United States;</footnote>

<footnote n="3">³Hematology Oncology, Stanford University Medical Center, Stanford, CA, United States</footnote>
initiated at 420 mg a day, and dose de-escalation for toxicity permitted. The median time on ibrutinib was 46 months. Improvements in categorical responses occurred with prolonged treatment, with overall (≥ minor response) and major (≥ partial response) response rates of 90.4% and 77.7%, respectively. At best response, median serum IgM level declined from 3,520 to 821 mg/dL (p<0.0001), bone marrow involvement declined from 60% to 20% (p<0.0001), and hemoglobin level rose from 10.5 to 14.2 g/dL (p<0.0001). Response attainment including the impact of MYD88 and CXCR4 mutation status on responses is shown in Table 1.

Adverse events (Grade ≥2) in ≥5% of patients during active follow-up were: neutropenia (22%); thrombocytopenia (14%), pneumonia

(9%); GERD (8%); hypertension (8%); anemia (6%); and skin infection (5%). Seven patients (11%) had an atrial arrhythmia at a median of 4 (range 0-33 months), and 6 continued ibrutinib following medical management of arrhythmia. The findings confirm that ibrutinib is highly active, and produces long-term responses in previously treated WM. Prolonged ibrutinib therapy is associated with deeper responses, including VGPR. Response activity, time to major response, and PFS are impacted by MYD88 and CXCR4 mutation status.

**Keywords:** ibrutinib; Waldenström's macroglobulinemia (WM).

**Disclosures:** Treon, S: Consultant Advisory Role: *Pharmacyclics*, Janssen; Research Funding: *Pharmacyclics*.

<table><thead><tr><th></th><th>All Patients*<br>(n=63)</th><th>MYD88<sup>MUT</sup>CXCR4<sup>WT</sup><br>(n=36)</th><th>MYD88<sup>MUT</sup>CXCR4<sup>Mut</sup><br>(n=22)</th><th>MYD88<sup>WT</sup>CXCR4<sup>WT</sup><br>(n=4)</th><th>P-value</th></tr></thead><tbody><tr><td>Overall<br>Responses<br>(%)</td><td>90.4</td><td>100</td><td>86.4</td><td>50.0</td><td>&lt;0.001</td></tr><tr><td>Major<br>Responses<br>(%)</td><td>77.7</td><td>97.2</td><td>63.6</td><td>0</td><td>&lt;0.001</td></tr><tr><td>VGPR (%)</td><td>28.6</td><td>44.4</td><td>9.1</td><td>0</td><td>&lt;0.001</td></tr><tr><td>Median<br>Time to<br>Minor<br>Response<br>or better<br>(months)</td><td>1.0<br>(range<br>1.0-22.5)</td><td>1.0<br>(range<br>1.0-15)</td><td>1.0<br>(range<br>1.0-22.5)</td><td>1.0</td><td>0.10</td></tr><tr><td>Median<br>Time to<br>Major<br>Response<br>(months)</td><td>2.0<br>(range<br>1.0-49)</td><td>2.0<br>(range<br>1.0-49)</td><td>6.0<br>(range<br>1.0-40)</td><td>N/A</td><td>0.05</td></tr></tbody></table>

*One patient had MYD88 mutation, but no CXCR4 mutation determination, and had stable disease.

**Figure 1** shows the Kaplan Meier curves for progression free survival (PFS) for all study participants (A), and by MYD88 and CXCR4 mutation status (B). The 5-year PFS for all patients was 54%. For patients with MYD88<sup>Mut</sup>CXCR4<sup>WT</sup>, the median PFS was not reached (5-year PFS 71%). For patients with MYD88<sup>Mut</sup>CXCR4<sup>Mut</sup>, median PFS was 42 months (5-year PFS 34%), and 54 months (5-year PFS 39%) if transformation for two patients attributed to prior nucleoside analogue exposure was not counted as ibrutinib-related progression. For those with MYD88<sup>WT</sup> disease, the median PFS was 5 months (Log-rank p<0.001 for 3-way comparison). The 5-year overall survival for all patients was 87%.

<figure><img src="image_104.png" /></figure>
# POSTER PRESENTATIONS

## BIOLOGY AND PATHOLOGY

### 136
ONE-YEAR REAL-LIFE TARGETED NEXT GENERATION SEQUENCING FOR LYMPHOMA DIAGNOSIS: STUDY OF PATIENTS FROM THE FRENCH LYMPHOMA NETWORK IN RHÔNE-ALPES

C. Bommier<fnref n="1" /> | C. Mauduit<fnref n="2" /> | J. Fontaine<fnref n="2" /> |

E. Bourbon<fnref n="2" /> | P. Sujobert³ | S. Huet³ |

L. Baseggio³ | S. Hayette³ | C. Laurent⁴ |

E. Bachy⁵ | H. Ghesquières⁵ | G. Salles⁵ |

A. Traverse-Glehen<fnref n="2" />

¹Haematology Department, Assistance Publique - Hôpitaux de Paris, Paris, France; ²Pathology Department, Hospices Civils de Lyon, Pierre-Bénite, France; ³Laboratory of Haematology, Hospices Civils de Lyon, Pierre-Bénite, France; ⁴Pathology Department, Institut Universitaire du Cancer - Oncopôle, Toulouse, France; ⁵Haematology Department, Hospices Civils de Lyon, Pierre-Bénite, France

**Introduction:** During last years, NGS studies, performed on patient cohorts, provided new insights into genomic characterization of lymphoma landscape. However, to date, the impact of NGS data on the daily diagnosis practice has not been reported yet. We reported here the clinical impact of targeted next generation sequencing (TNGS) in lymphoma diagnosis after expert histological review in Rhône-Alpes (France).

**Materials and Methods:** In France, difficult lymphoma diagnoses are systematically reviewed, in real time, by histological experts through the Lymphopath Network. To increase diagnosis accuracy, we used a TNGS approach to identify pathogenic genomic variants that could be helpful in lymphoma diagnosis. From 12/2017 to 12/2018, we performed TNGS on tumour biopsy (FFPE or frozen) samples from primary CNS lymphomas and lymphoma of difficult diagnosis, that were histologically reviewed in Lyon Pathology Department. Because a difficult diagnosis implies a doubt between several entities, benign conditions were classified with the lymphoma they were suspect of. We used a panel of 46 genes, chosen after an extensive literature review of NGS lymphoma studies. Impact of TNGS data on histological diagnosis was classified as follows: confirms diagnosis; changes diagnosis; does not help. The term concordance was defined as the addition of "confirms" and "does not help". To evaluate the potential

impact on patient care, modifications into the final diagnosis were divided into major and minor changes according to the ESMO guidelines.

**Results:** Among the 230 patients and after expert histological reviewing, 20 (8.6%) were suspected of primary CNS lymphoma (PCNSL), 47 (20.3%) of large B-cell lymphoma (LBCL), 90 (38.7%) of small B-cell lymphoma (SBCL), 6 (2.6%) of Hodgkin lymphoma (HL), 56 (23.9%) of TFH T-cell lymphoma and 12 (5.7%) of non-TFH T-cell lymphoma. After TNGS, the overall concordance rate was 85.3%, from 76.9% in non-TFH T-cell lymphoma to 100% in PCNSL and HL. TNGS confirmed the histological diagnosis in 122 cases (53%), changed the diagnosis in 33 cases (14.3%) and did not bring any help in 75 cases (32.6%, from 10% in PCNSL to 100% in HL). Modifications between initial and final diagnosis had an impact on patient care for 11.3% of cases (26/230). Diagnosis modifications occurred in all types of lymphoma except PCNSL and HL, and the highest modification rate was in TFH and in non-TFH T-cell lymphoma, 21.8% and 23.1%, respectively. In about 2/3rd (65.4%) of the cases of changes, reclassification of the lymphoma subtype had a direct therapeutic impact, whereas only 12.1% of the changes were a reclassification between benign and malignant.

**Conclusions:** This study highlights that TNGS may directly contribute to a more accurate diagnosis in lymphoma patients and improve their clinical management in routine. One current limitation is the lack of sensitivity of TNGS in lymphoma with low tumour infiltration.

**Keywords:** B-cell lymphoma; molecular genetics; T-cell lymphoma (TCL).

### 137
MUTATIONAL LANDSCAPE OF DIFFUSE LARGE B-CELL LYMPHOMA (DLBCL) AT DIAGNOSIS AND AT PROGRESSION ASSESSED BY CIRCULATING TUMOR DNA ANALYSIS

A. Rivas-Delgado<fnref n="1" /> | F. Nadeu<fnref n="2" /> | A. Enjuanes<fnref n="2" /> |

L. Magnano³ | N. Castrejón de Anta⁴ | P. Mozas<fnref n="1" /> |

T. Baumann<fnref n="1" /> | J. Delgado<fnref n="1" /> | O. Balagué⁴ |

N. Villamor³ | E. Campo⁴ | E. Giné<fnref n="1" /> |

A. López-Guillermo<fnref n="1" />

<footnote n="1">¹Hematology Department, Hospital Clínic de Barcelona, Barcelona, Spain;</footnote>

<footnote n="2">²Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Barcelona, Spain; ³Hematopathology Unit, Department of</footnote>
*Pathology, Hospital Clínic de Barcelona, Barcelona, Spain; *Department of Pathology, Hospital Clínic de Barcelona, Barcelona, Spain*

**Introduction:** Previous studies have highlighted the potential of circulating tumor DNA (ctDNA) to determine the mutational profile of DLBCL, and assess the molecular changes over time and the genetic mechanisms of resistance. In addition, the quantity of ctDNA could also predict the response and outcome of the patients. The aim of this study was to analyze the mutational profile at diagnosis and its dynamics after frontline treatment and in the refractory/relapse settings.

**Methods:** We included 65 patients (M/F 32/33, median age 64 years) diagnosed with DLBCL in a single institution between 2016 and 2018 according to the WHO criteria. All patients were treated with chemoimmunotherapy. After initial treatment, 47 patients achieved CR, 4 PR, 7 were refractory and in 7 cases the response was not evolvable. Samples were obtained both at diagnosis and at relapse/progression in refractory/relapsed patients. Tumor genomic DNA (gDNA) was isolated from formalin-fixed paraffin-embedded (FFPE) diagnostic tissue biopsies and at relapse when available. A panel of 115 genes was amplified using a hybridization capture based protocol from 10-30 ng of ctDNA and 150 ng of gDNA (SureSelectXT-Agilent Technologies) and sequenced in a MiSeq instrument (Illumina).

**Results:** ctDNA was obtained from all patients at diagnosis (median of 34 ng; range: 10-1507 ng) and from 12 refractory/relapsed cases. At least one mutation could be detected in 88% of the cases. Median number of mutations per sample was 6 (0-21 mutations). The genes most frequently mutated at diagnosis in plasma samples were KMT2D, TP53, MYD88, TNFRSF14, PIM1, CREBBP, BCL2 and EP300. In 38 cases, paired FFPE samples were available as detailed in the figure. Sensitivity of ctDNA to detect tumor mutations at baseline FFPE samples was 75% (95%IC: 69.5-80.5). Of note, most of the cases in which mutations were not detected in the ctDNA had a primary extranodal origin. In the 12 cases with a ctDNA sample at diagnosis and at progression, 5 cases showed the same mutational profile, whereas in 6 cases a change in the number of mutated genes was observed (3 cases had fewer mutations; 3 cases

had new mutations) and in one case no mutations were detected at relapse. In addition, selection of minor subclonal mutations was observed in 2 cases. Patients with high pretreatment ctDNA levels (>3 log hGE/mL) had a worse PFS and OS than those with low levels (18-month PFS 24 vs 77%; 18-month OS 58 vs 94%; p<0.004).

**Conclusions:** ctDNA shows a good correlation with the information obtained in the tumor. Therefore it could be a valuable tool to assess the mutational profile both at diagnosis and at relapse. Pretreatment ctDNA levels have an impact on outcome.

**Keywords:** diffuse large B-cell lymphoma (DLBCL); molecular genetics.

## 138
# TARGETED GENOTYPING OF CIRCULATING TUMOR DNA FOR CLASSICAL HODGKIN LYMPHOMA MONITORING: A PROSPECTIVE STUDY

V. Camus¹ | M. Viennot² | P. Viailly² | E. Bohers² |
L. Bessi² | B. Marcq¹ | P. Etancelin³ |
J. Picquenot⁴ | M. Comic⁴ | L. Burel⁵ | J. Loret⁵ |
S. Becker⁶ | P. Lenain¹ | S. Lepretre¹ | E. Lemasle¹ |
H. Lanic¹ | A. Menard¹ | N. Contentin¹ | H. Tilly¹ |
A. Stamatoullas¹ | F. Jardin¹

¹INSERM U1245 and Department of Hematology, Centre Henri Becquerel, Rouen, France; ²INSERM U1245, Centre Henri Becquerel, Rouen, France; ³Department of Genetic Oncology, INSERM U1245, Rouen, France; ⁴Department of Pathology, INSERM U1245, Rouen, France; ⁵Clinical Research Unit, Centre Henri Becquerel, Rouen, France; ⁶Department of Nuclear Medicine and Radiology, QuantIF, Rouen, France

**Introduction:** The relevance of circulating tumor DNA (ctDNA) analysis as a liquid biopsy and minimal residual disease tool in the management of classical Hodgkin Lymphoma (cHL) patients was demonstrated in retrospective settings and remains to be confirmed.

**Methods:** We developed a targeted Next-Generation sequencing (NGS) panel for fast analysis (AmpliSeq® technology) of nine commonly mutated genes in biopsy and ctDNA of cHL patients. We then conducted a prospective trial to assess ctDNA follow up at diagnosis and after 2 cycles of chemotherapy (C2). A dedicated bioinformatics pipeline to optimize detections of variants with low rates and minimize artefactual misinterpretations was built. Sixty cHL patients treated by first line conventional chemotherapy (BEACOPPescalated [21.3%], ABVD/ABVD-like [73.5%] and other regimens [5.2%, for elderly patients] were included in this non-interventional study (NCT02815137).

**Results:** Median age of the patients was 33.5 years (range 20-86) with a predominance of male patients, scleronodular subtype and ECOG 0-1 (53.3%, 70% and 88.3%, respectively). Variants were

<figure><img src="image_105.png" /></figure>
<figure><img src="image_106.png" /><figcaption>Figure 1A</figcaption></figure>

identified in 33 (55%) patients, precisely in 16/30 (53.3%) and 30/60 (50%) of available biopsy and ctDNA samples respectively. Concordance between genetic profiles of biopsy and ctDNA was accurate for 22/30 patients (73.3%). Mutations of *NFKBIE*, *TNFAIP3*, *STAT6*, *PTPN1*, *B2M*, *XPO1*, *ITPKB*, *GNA13* and *SOCS1* were found in 11.7% (mean number of variants by sample [range]: 1 [0-1]), 25% (1.1 [0-2]), 21.7% (1.4 [0-2]), 1.7% (1 [0-1]), 25% (1.3 [0-3]), 6.7% (1 [0-1]), 15% (1.4 [0-3]), 5% (1.3 [0-2]) and 31.7% (1.8 [0-7]) of all patients, respectively. Unsupervised hierarchical clustering was performed among the 9 genes to represent the association of alterations (See Figure 1).

Higher level of [ctDNA] at diagnosis was associated with adverse characteristics: age ≥45 years, presence of anemia (hemoglobin <10.5g/dl), albuminemia <40g/l, sedimentation rate ≥50mm, stage III-IV, lymphocytes count <0.6 G/L, presence of B symptoms, International prognostic Index ≥3, elevated LDH. The *ITPKB* and *B2M* mutated patients displayed more disseminated disease (≥ 4 median nodal areas versus [vs] 3 for non-mutated patients, p = 0.005) and *XPO1* mutations were associated with female sex (p = 0.042). Median VAF were higher in ctDNA than in biopsy (3.23% vs 2.15%, p = 0.023) and there was a moderate correlation between higher metabolic tumor volume (MTV) and higher [ctDNA] (r = 0.36, p = 0.005).

Regarding early therapeutic response, 45 patients (83%, NA = 6) had a negative positron emission tomography (PET) after C2 (Deauville Score 1-3). Mean of DeltaSUVmax after C2 was -78.8%. We analyzed ctDNA after C2 for 45 patients (70%). A rapid clearance of ctDNA in all cases was observed after C2.

**Conclusions:** Variants detection in ctDNA is suitable to depict the genetic features of cHL at diagnosis and may help to assess early treatment response, in complement to PET. [ctDNA] level and genotype are correlated with clinical characteristics and presentation.

<figure><img src="image_107.png" /><figcaption>Figure 1B</figcaption></figure>

**Keywords:** classical Hodgkin lymphoma (cHL); minimal residual disease (MRD); molecular genetics.

139

ANALYSIS OF CIRCULATING TUMOR DNA
(ctDNA) IN CEREBROSPINAL FLUID
DETECTS THE PRESENCE OF CENTRAL
NERVOUS SYSTEM (CNS) INVOLVEMENT
IN B-CELL LYMPHOMAS

S. Bobillo¹ | M. Crespo¹ | L. Escudero² |

R. Mayor² | P. Raheja¹ | P. Abrisqueta¹ |

C. Palacio-Garcia¹ | J. Montoro¹ | I. Jimenez¹ |

J.C. Nieto¹ | J. Carabia¹ | F. Martinez-Ricarte³ |

J. Castellvi⁴ | L. Puigdefabregas¹ | F. Bosch¹ | J. Seoane²

¹Laboratory of Experimental Hematology, Department of Hematology, Vall d'Hebron Institute of Oncology (VHIO), Vall d'Hebron University Hospital, Barcelona, Spain; ²Gene Expression and Cancer Group, Vall d'Hebron Institute of Oncology (VHIO), Vall d'Hebron University Hospital (HUVH), Barcelona, Spain; ³Department of Neurosurgery, Vall d'Hebron University Hospital (HUVH), Barcelona, Spain; ⁴Department of Pathology, Vall d'Hebron University Hospital, Barcelona, Spain

**Introduction:** Central nervous system (CNS) involvement in B-cell malignancies is associated with frequent relapses and poor prognosis. Recently, the presence of circulating tumor DNA (ctDNA) in plasma has been correlated with treatment response and outcome in B-cell malignancies. In brain tumors, cerebrospinal fluid (CSF) ctDNA better represents the tumoral mutational profile than plasma. Against this background, we hypothesized that in CNS lymphomas (CNSL), ctDNA
<figure><img src="image_108.png" /><figcaption>**Figure 1:** Analysis of ctDNA in CSF and plasma in patients with restricted CNS disease and changes in ctDNA during treatment.</figcaption></figure>

analysis in CSF could be useful to detect the disease and to appraise the response to treatment. Furthermore, CSF ctDNA could help to detect occult leptomeningeal (LM) disease.

**Methods:** Fifteen patients diagnosed with the following conditions were included: primary CNSL (PCNSL), n = 1; secondary CNSL (SCNSL), n = 3; systemic diffuse large B cell lymphoma (DLBCL) with risk factor for CNS relapse, n = 9; and Burkitt lymphoma (BL), n = 2. CSF and plasma were collected before treatment in all patients and sequentially in 11. Tumors were sequenced using whole exome sequencing (n = 6) or a next generation sequencing panel (n = 11) to identify at least 1 somatic mutation. Two patients had a MYD88 mutation previously identified by Sanger sequencing. We next designed personalized droplet-digital PCR assays for each mutation. Conventional cytology (CC) and flow cytometry (FC) were performed in all CSF samples.

**Results:** We detected ctDNA in the CSF from all patients with CNSL (PCNSL, n = 1; SCNSL, n = 3). In these 4 cases with restricted CNS disease, the variant allele frequencies (VAFs) in CSF were higher than in plasma. Moreover, in patients with sequential samples (n = 3) we

observed that VAFs of CSF ctDNA decreased with response to therapy while increased with disease progression (Figure 1). Finally, in these 4 patients, LM disease was detected by FC in 3 patients and undetected by FC or CC in 1 patient. As per systemic lymphoma, 11 patients without detectable LM disease (negative CC and FC) and risk factors for CNS relapse (DLBCL, n = 9; BL, n = 2) were included. Interestingly, we detected CSF ctDNA in 2 cases, with similar VAFs in CSF and plasma. In the first patient, the CSF ctDNA disappeared after the first cycle of therapy and no CNS relapse has been observed to date (follow-up 15 months), while the other one died shortly after treatment due to progression. In the remaining 9 cases in whom CSF ctDNA was not detected, no CNS relapse was observed after a median follow-up of 18 months. Notably, in 7 out of these 9 cases ctDNA was found in plasma, these levels of ctDNA decreasing after treatment in all patients with PET response (n = 5).

**Conclusions:** In this study, we demonstrated that the presence of ctDNA in CSF of patients with CNSL correlates with tumor burden. In addition, we showed that in patients with CNS involvement, CSF
ctDNA could be a very sensitive method in assessing the tumor burden at diagnosis and the response to treatment.

**Keywords:** diffuse large B-cell lymphoma (DLBCL); primary CNS lymphoma (PCNSL).

## 140 MOLECULAR ANALYSES AND AN INNOVATIVE DIAGNOSTIC ALGORITHM IN MYC-NEGATIVE BURKITT-LIKE LYMPHOMA WITH 11Q ABERRATION: A SINGLE INSTITUTION EXPERIENCE

G. Rymkiewicz<fnref n="1" /> | M. Zajdel<fnref n="2" /> | A. Paziewska³ |
K. Blachnio<fnref n="1" /> | B. Grygalewicz⁴ | R. Woroniecka⁴ |
M. Dabrowska³ | Z. Bystydzienski<fnref n="1" /> |
J. Romejko-Jarosinska<fnref n="5" /> | M. Kulecka³ | M. Kulinczak<fnref n="2" /> |
M. Sromek<fnref n="2" /> | J. Rygier⁴ | A. Borysiuk<fnref n="1" /> |
B. Pienkowska-Grela⁴ | K. Czyz-Domanska<fnref n="5" /> |
J. Miloszewska<fnref n="2" /> | L. Szafron<fnref n="2" /> |
M. Prochorec-Sobieszek<fnref n="1" /> | J. Walewski<fnref n="5" /> |
J. Ostrowski⁶ | J.K. Siwicki<fnref n="2" /> | M. Chechlinska<fnref n="2" />

Burkitt-like lymphoma with 11q aberration (BLL,11q) is a new entity of a germinal center (GCB)-derived, highly aggressive B-cell lymphoma. Clinically and pathomorphologically, BLL,11q resembles Burkitt lymphoma (BL), but it lacks MYCrearrangements and presents proximal gains and distal losses in chromosome 11. In the updated 2017 WHO classification, BLL,11q has been recognized as a provisional entity. BLL,11q could be promoted to definite lymphomas but for this purpose it is necessary to publish as many new cases as possible, and more molecular studies are expected to add to an understanding and managing of this very rare malignancy.

Still, the recognition of BLL,11q entity is clinically relevant because a favorable outcome is observed after BL-directed therapy. Unfortunately, the routine diagnosis of BLL,11q is difficult, and BLL,11q is often misdiagnosed by histopathology and due to the lack of MYC rearrangement it is inappropriately treated. To the best of our knowledge, we have so far published the largest cohort of BLL,11q and of BL cases carrying both MYC rearrangement and 11 aberration. Our initial RT-qPCR-based miRNA studies showed similarities of BLL,11q (n = 12) to BL

(n = 34), but not to DLBCL (n = 49) in miR-155, miR-21 and mir-26a expression. Next, a detailed immunohistochemical and flow cytometry analysis of 10 BLL,11q and 23 MYC-positive BL cases revealed similarities along with subtle but essential differences in BLL,11q and BL immunophenotypes.

We also correlated the occurrence of bulky tumors in BLL,11q with amplification of the 11q23.3 region, where KMT2A is located. Most recently, by next generation sequencing of 10 BL and 7 BLL,11q, we identified 49 microRNAs and 2572 mRNA transcripts differentially expressed between BL and BLL,11q. Accumulating data show significant differences between sporadic BL and BLL,11q in mRNA and microRNA profiles, and point to different chromosomal and mutational profiles of BLL,11q from BL, and additionally from other aggressive GCB-lymphomas. Thus, BLL,11q seems indeed to be a molecularly distinct category. Still, BLL,11q patients, if treated with BL-directed regimen, have a relapse-free outcome similar to BL patients.

We proposed an original and practical flow cytometry- and immunohistochemistry-based diagnostic algorithm for the differential diagnosis of BLL,11q vs. BL and other aggressive lymphomas which enables BLL,11q diagnosis within 1.5 hours following fine needle aspiration biopsy procedure.

**Keywords:** Burkitt lymphoma (BL); fine-needle aspirate (FNA); flow cytometry.

**Disclosures:** Rymkiewicz, G: Other Remuneration: Roche, fee, travel expenses.

## 141 HIGH RISK OF ADVERSE EVENTS AFTER AUTOLOGOUS STEM-CELL TRANSPLANTATION IN LYMPHOMA PATIENTS WITH DNA REPAIR PATHWAY MUTATIONS: A NATION-WIDE COHORT STUDY

S. Husby<fnref n="1" /> | F. Favero<fnref n="2" /> | C. Nielsen³ |
B. Sørensen⁴ | J. Bæch<fnref n="5" /> | J.W. Hansen<fnref n="1" /> |
F.G. Rodriguez-Gonzalez<fnref n="2" /> | B. Arboe<fnref n="1" /> | P.L. Andersen⁶ |
E.K. Haastrup⁷ | A. Fischer-Nielsen⁷ | S.G. Sækmose⁸ |
P.B. Hansen⁹ | I. Christiansen¹⁰ | E. Clasen-Linde¹¹ |
L.M. Knudsen¹² | K. Grell¹³ | E.K. Segel¹⁴ |
L.H. Ebbesen¹⁴ | M. Thorsgaard¹⁴ | P.L. Josefsson¹² |
T.C. El-Galaly¹⁰ | P.D. Brown<fnref n="1" /> | J. Weischenfeldt<fnref n="2" /> |
T.S. Larsen¹⁵ | K. Grønbæk<fnref n="1" />

<footnote n="1">¹Department of Pathology and Laboratory Diagnostics, Maria Sklodowska-Curie Institute—Oncology Center, Warsaw, Poland;</footnote>

<footnote n="2">²Department of Immunology, Maria Sklodowska-Curie Institute—Oncology Center, Warsaw, Poland; ³Department of Gastroenterology, Hepatology and Clinical Oncology, Centre of Postgraduate Medical Education, Warsaw, Poland; ⁴Cytogenetics Laboratory, Maria Sklodowska-Curie Institute—Oncology Center, Warsaw, Poland;</footnote>

<footnote n="5">⁵Department of Lymphoid Malignancies, Maria Sklodowska-Curie Institute—Oncology Center, Warsaw, Poland; ⁶Department of Genetics, Maria Sklodowska-Curie Institute—Oncology Center, Warsaw, Poland</footnote>

<footnote n="1">¹Dept. of Hematology, Rigshospitalet, Copenhagen N, Denmark; ²Biotech Research & Innovation Center (BRIC), University of Copenhagen, Copenhagen, Denmark; ³Dept. of Immunology, Odense University Hospital, Odense, Denmark; ⁴Dept. of Immunology, Aarhus University Hospital, Aarhus, Denmark; ⁵Dept. of Immunology, Aalborg University Hospital, Aalborg, Denmark; ⁶Dept. of Immunology, Herlev University Hospital, Herlev, Denmark; ⁷Dept. of Immunology, Rigshospitalet,</footnote>
Cum. incidence of admission to intensive care

<figure><img src="image_109.png" /></figure>

Copenhagen, Denmark; ⁸Dept. of Immunology, Roskilde University
Hospital, Næstved, Denmark; ⁹Dept. of Hematology, Roskilde University
Hospital, Roskilde, Denmark; ¹⁰Dept. of Hematology, Aalborg University
Hospitale, Aalborg, Denmark; ¹¹Dept. of Pathology, Rigshospitalet,
Copenhagen, Denmark; ¹²Dept. of Hematology, Herlev University
Hospital, Herlev, Denmark; ¹³Dept. of Biostatistics, University of
Copenhagen, Copenhagen, Denmark; ¹⁴Dept. of Hematology, Aarhus
University Hospital, Aarhus, Denmark; ¹⁵Dept. of Hematology, Odense
University Hospital, Odense, Denmark

**Introduction:** It is estimated that at least 30% of patients with lymphoma die within five years after autologous stem-cell transplantation (ASCT). A substantial fraction of patients succumb to therapy-related side effects. Identifying patients not suited for ASCT has so far been challenging, but clonal hematopoiesis (CHIP) mutations in peripheral blood and/or bone marrow has in single-center studies been proposed as markers of vulnerability. We performed a national population-based analysis of CHIP in lymphoma patients undergoing ASCT to investigate this.

**Methods:** Patients in Denmark with a lymphoma diagnosis (both Non-Hodgkin and Hodgkin lymphoma) and a registered autologous stem cell sample harvested at Danish transplant centers between January 1, 2000 and July 1, 2012 were included. We performed targeted next generation sequencing (NGS) of autologous stem cell harvest material with a panel covering 21 of the most commonly mutated genes in clonal hematopoiesis. To allow accurate mutation calling unique molecular identifiers (UMI's) were employed and a median coverage of 5832X was obtained.

We retrieved prospective clinical data from five independent nationwide registries covering death, relapse, severe infections (sepsis and

invasive fungal infection), secondary malignancies, days in hospital, use of transfusion products (red blood cell and platelets), and intensive care admission.

**Results:** A total of 892 patients were identified; 565 patients fit inclusion criteria and were sequenced. The median follow-up was 9.1 years (IQR 7.0–10.3). Of these, 440 patients were intended for immediate ASCT, 121 patients had stem cells harvested as part of a 'rainy day strategy', and 4 patients had unknown infusion status. CHIP mutations were identified in 112 patients (25.5%) intended for immediate ASCT. These mutations were, in contrast to findings in single-center studies, not associated with a significant inferior overall survival after adjusting for age, sex, and line of therapy (hazard ratio [HR] 1.36, 95%CI 0.93–1.99, p = 0.11). However, patients with mutations in DNA repair pathway genes (PPM1D, TP53, BRCC3, and RAD21; 9.1% of patients in the cohort) had a significant independent inferior overall survival (adjusted HR 2.37, 95%CI 1.44–3.90, p<0.0001). In addition, patients with DNA repair pathway mutations had a significant higher incidence of admission to intensive care (p = 0.019; **Figure 1**), a significant higher incidence of therapy-related leukemia (p = 0.0018), and a non-significant higher incidence of severe infections (p = 0.061). We also found that these patients had a significantly increased number of days in hospital following ASCT (p = 0.0025).

**Conclusions:** This nationwide population-based study show that patients with lymphoma who carry clonal hematopoiesis mutations in genes of the DNA repair pathway (PPM1D, TP53, BRCC3, and RAD21) have a significant independent inferior overall survival (p<0.0001) and an increased risk of several adverse events after ASCT.

**Keywords:** autologous stem cell transplantation (ASCT); clonal hematopoiesis; non-Hodgkin lymphoma (NHL).
142
EZH2 GAIN-OF-FUNCTION MUTATIONS ARE NOT ASSOCIATED WITH MORE FAVORABLE PROGNOSIS IN RELAPSED/REFRACTORY FOLLICULAR LYMPHOMA (FL): A PRELIMINARY ANALYSIS ON 590 PATIENTS

J. Okosun¹ | C. Bödör² | C. Batlevi³ | N. Nagy⁴ |

J. Michot⁵ | T. Schneider⁶ | H. Alizadeh⁷ |

Z. Simon⁸ | J. Vose⁹ | A. Younes³ | V. Ribrag¹⁰ |

J. Fitzgibbon¹ | J. Yang¹¹ | S. Agarwal¹² |

K.J. Newberry¹³ | N.R. Michaud¹⁴

¹Hematology, Barts Cancer Institute, Queen Mary University of London, London, United Kingdom; ²Hematology, Semmelweis University, Budapest, Hungary; ³Medical Oncology, Memorial Sloan Kettering Cancer Center, New York, United States; ⁴Cancer Research, Semmelweis University, Budapest, Hungary; ⁵Hematology and Innovative Drugs, Gustave Roussy, Villejuif, France; ⁶Medical Oncology and Hematology, National Institute of Oncology, Budapest, Hungary; ⁷Internal Medicine, University of Pecs, Pecs, Hungary; ⁸Biochemistry and Molecular Biology, University of Debrecen, Debrecen, Hungary; ⁹Oncology & Hematology, University of Nebraska Medical Center, Omaha, United States; ¹⁰DITEP, Gustave Roussy, Villejuif, France; ¹¹Biostatistics, Epizyme, Cambridge, United States; ¹²Chief Medical Officer, Epizyme, Cambridge, United States; ¹³Clinical Research, Epizyme, Cambridge, United States; ¹⁴Translational Medicine, Epizyme, Cambridge, United States

**Background:** Tazemetostat, a selective, oral inhibitor of the histone methyltransferase EZH2, has shown antitumor activity in FL. Gain-of-function (GOF) mutations in EZH2 are found in 20-25% of FL tumors. Mutant (MT) EZH2 is widely considered an oncogenic driver of FL. Some studies suggest GOF EZH2 mutations provide a prognostic benefit in the frontline setting (1L) in FL patients (pts) treated with immunochemotherapy (ICT). However, the impact of MT EZH2 on clinical outcomes in relapsed/refractory (R/R) FL pts receiving systemic anticancer therapy beyond frontline ICT is unknown. We present interim results from a multicenter study

evaluating the impact of EZH2 activating mutations on FL pt outcomes.

**Methods:** Retrospective data on therapy types and clinical outcomes are being collected from 5 academic sites. Available data from 3 sites (Barts Cancer Institute, Institute Gustave Roussy, Semmelweis University) were analyzed to determine and compare clinical outcome parameters with regard to EZH2 mutation. Best overall response rate (ORR), per best judgment of the treating physician, was compared by EZH2 status and stratified by line of therapy using Cochran-Mantel-Haenszel chi-square test. Progression-free survival (PFS) and overall survival (OS) were calculated using the Kaplan-Meier method and compared by the logrank test. Tumor tissues, collected primarily at time of diagnosis, were analyzed for activating EZH2 mutations (Y646X, A682G, A692V) via various approaches, including next generation sequencing, digital droplet PCR (BioRad) and the cobas® EZH2 Mutation Test (Roche Molecular Systems).

**Results:** Data from 590 pts with EZH2 MT (n = 140) or wild-type (WT; n = 450) FL treated with systemic anticancer therapy between 1972-2017 were analysed. EZH2 activating mutation frequency was 24%. In 1L, 43% of pts received ICT. In second line (2L) and beyond, 65-80% of pts received chemotherapy and 14-20% received ICT. Median follow-up from diagnosis was 10.5y (95% CI, 9.7-11.5). No significant differences in ORR between MT and WT EZH2 cohorts were found in 1L, 2L, or third line and beyond (3L+). In the combined dataset, ORR for MT and WT EZH2 cases in 1L were 89% and 87%, respectively (P = 0.493), 73% and 73%, respectively (P = 0.996) in 2L, and 82% and 80%, respectively (P = 0.647) in 3L+. There were no significant differences (P>0.05) in PFS between R/R FL pts with MT and WT EZH2 for any line of therapy. In addition, OS was not significantly different for pts with and without EZH2 mutations (median OS 12.7 vs 16.6y; P = 0.464; Figure).

**Conclusion:** No differences were observed in ORR or PFS by line of therapy in R/R FL pts with MT or WT EZH2. Similarly, MT EZH2 was not associated with significantly longer OS. Findings suggest that MT EZH2 is not a positive prognostic factor and clinical activity observed in pts with R/R FL treated with standard of care agents or tazemetostat is likely due to the drugs' mechanism of action.

**Keywords:** EZH2; follicular lymphoma (FL).

<figure><img src="image_110.png" /></figure>
**Disclosures:** Michot, J: Consultant Advisory Role: Abbvie, Aduro, Agios, Amgen, Argen-x, Astex, AstraZeneca, Aveo pharmaceuticals, Bayer, Beigene, Blueprint, BMS, Boeringer Ingelheim, Celgene, Chugai, Clovis, Daiichi Sankyo, Debiopharm, Eisai, Eos, Exelixis, Forma, Gamamabs, Genentech, Gortec, GSK, H3 biomedecine, Incyte, Innate Pharma, Janssen, Kura Oncology, Kyowa, Lilly, Loxo, Lysarc, Lytix Biopharma, Medimmune, Menarini, Merus, MSD, Nanobiotix, Nektar Therapeutics, Novartis, Octimet, Oncoethix, Oncopeptides AB, Orion, Pfizer, Pharmamar, Pierre Fabre, Roche, Sanofi, Servier, Sierra Oncology, Taiho, Takeda, Tesaro, Xencor; Honoraria: Bristol-Myers Squibb, AstraZeneca, Janssen; Other Remuneration: AstraZeneca, Roche, Novartis, Gilead, Celgene, Bristol-Myers Squibb. Vose, J: Honoraria: Novartis, Abbvie, Epizyme, Roche, Legend Pharmaceuticals, Kyopharm, Sandoz, Vaniam Group, Janssen/Pharmacyclics, Kite Pharma, Acerta/Astra-Zeneca, Nordic Nanovector, Verastem; Research Funding: Amgen, Acerta Pharma, Astra-Zeneca, Bristol - Myers Squibb, Celgene, Incyte Corp., Kite Pharma, Merck, Novartis, Seattle Genetics, Inc.; Younes, A: Consultant Advisory Role: BMS, Incyte, Janssen, Genentech and Merck; Honoraria: Genentech, Merck, Takeda, Incyte, BMS, AbbVie; Research Funding: Novartis, J&J, Curis, Roche, BMS; Ribrag, V: Consultant Advisory Role: Epizyme, Servier, Nanostring, Gilead, Pharmamar, BMS, MSD, Incyte, Roche, Infinity; Honoraria: ESAI; Research Funding: Epizyme, ArgenX; Fitzgibbon, J: Consultant Advisory Role: Epizyme, Gilead, Roche; Research Funding: Epizyme; Yang, J: Employment Leadership Position: Epizyme, Inc; Stock Ownership: Epizyme, Inc; Agarwal, S: Employment Leadership Position: Epizyme, Inc; Stock Ownership: Epizyme, Inc; Newberry, K: Employment Leadership Position: Epizyme, Inc; Stock Ownership: Epizyme, Inc; Michaud, N: Employment Leadership Position: Epizyme, Inc; Stock Ownership: Epizyme, Inc.

143
TREATMENT-DEPENDENCE OF HIGH-RISK
GENE EXPRESSION SIGNATURES IN DE
NOVO FOLLICULAR LYMPHOMA

C.R. Bolen¹ | W. Hiddemann² | R. Marcus³ |

M. Herold⁴ | S. Huet⁵ | G. Salles⁶ | F. Mattiello⁷ |

T. Nielsen⁷ | F. Mir⁷ | J.M. Venstrom¹ |

M.Z. Oestergaard⁸

¹Bioinformatics & Computational Biology, Genentech Inc., South San Francisco, United States; ²Department of Medicine III, University Hospital, LMU Munich, Munich, Germany; ³Department of Haematology, Kings College Hospital, London, United Kingdom; ⁴Leiter Onkologisches Zentrum, HELIOS-Klinikum Erfurt, Erfurt, Germany; ⁵Equipe Labellisée Ligue Contre le Cancer; Laboratoire d'Hématologie; Faculté de Pharmacie Rockefeller, Cancer Research Centre of Lyon; Hospices Civils de Lyon, Centre Hospitalier Lyon-Sud, Claude Bernard University Lyon-1, Oullins, Pierre Bénite, Lyon, France; ⁶Equipe Labellisée Ligue Contre le Cancer; Service d'Hematologie Clinique, Cancer Research Centre of Lyon, Hospices Civils de Lyon et Université Claude Bernard Lyon-1, Oullins, Pierre-Bénite, France; ⁷Pharma Development Clinical Oncology,

F. Hoffmann-La Roche Ltd, Basel, Switzerland; ⁸Oncology Biomarker Development, F. Hoffmann-La Roche Ltd, Basel, Switzerland

**Background:** De novo follicular lymphoma (FL) is an indolent disease with good prognosis, but some patients (pts) with FL who relapse early (progression within 24 months) have significantly worse outcomes (Casulo and Barr. Blood 2019). We evaluated the performance and treatment-dependence of two high-risk FL models in pts with FL treated in the Phase III GALLIUM trial (NCT01332968).

**Methods:** Enrolled pts (age ≥18 years with previously untreated advanced-stage FL) were randomised to receive either obinutuzumab (G)- or rituximab (R)-based immunochemotherapy plus maintenance. The chemotherapy arm (CHOP, CVP, or bendamustine [benda]) was selected by each study centre (33%; 10%; 57%, respectively). Pt samples with available tumour tissue (n = 274) were profiled by RNASeq; normalised counts were combined using either the published weights (23-gene signature model) or principal component analysis (six-gene T-effector signature) (Huet et al. Lancet Oncol 2018; Bolen et al. Blood Adv 2017). High-risk pts were defined as the top 25th (23-gene signature) or top 75th (T-effector signature) percentile in order to align with Huet et al. (2018) prevalence. P-values were calculated using Cox-proportional-hazards (PH) after controlling for treatment arm, sex, FL International Prognostic Index (FLIPI), and geographic region.

**Results:** In 274 evaluable FL pts, the 23-gene signature high-risk group was not significantly associated with progression-free survival (PFS; p = 0.97). However, the 23-gene signature appeared to capture high-risk biology in pts treated with CHOP/CVP (PFS hazard ratio [HR]: 2.40 [range: 1.19–4.85]; p = 0.015; **Figure 1A**). Pts defined by the 23-gene signature as high risk performed better than low-risk pts in the benda cohort (PFS HR: 0.43 [range: 0.20–0.92]; p = 0.031), with similar trends in the R-benda (PFS HR: 0.54 [range: 0.22–1.3]; p = 0.18) and G-benda (PFS HR: 0.3 [range: 0.06–1.3]; p = 0.11) arms, representing a highly significant chemotherapy-dependent interaction (interaction p<0.001). None of the individual 23 signature genes were consistently prognostic in both treatment regimens. Significant chemotherapy dependence was observed for ABCB1, SEMA4B, FOXO1, PRDM15, AFF3, ALDH2, and KIAA0040 (interaction p<0.05), suggesting that benda may overcome some of the high-risk biology connected with cell cycle or cell migration. A different treatment dependence was also seen in other prognostic signatures, including the T-effector signature (interaction p = 0.001), where a subset of pts defined as low risk with CHOP/CVP treatment captured high-risk biology among pts treated with a benda backbone (PFS HR: 0.48 [range: 0.27–0.85]; p = 0.012; **Figure 1B**).

**Conclusions:** We identified a significant chemotherapy-dependent interaction for two high-risk signatures in de novo FL, highlighting the challenges of building high-risk signatures for pts independent of treatment.

**Acknowledgement:** This work was funded by F. Hoffmann-La Roche Ltd. Third-party editorial assistance, under the direction of Christopher Bolen, was provided by Louise Profit and Russell Craddock of Gardiner-Caldwell Communications, and was funded by F. Hoffmann-La Roche Ltd.

This abstract has been previously submitted to EHA 2019.
<figure><img src="image_111.png" /><figcaption>**Figure 1.** Progression-free survival split by (A) 23-gene signature or (B) T-effector signature is shown for CHOP/CVP-treated FL patients or bendamustine- treated FL patients. Hazard ratios and p-values were calculated using Cox-proportional hazards, after adjusting for treatment arm, sex, FLIPI, and geographic region. (Teff: T-effector signature)</figcaption></figure>

**Keywords:** follicular lymphoma (FL); gene expression profile (GEP); obinutuzumab.

**Disclosures:** Bolen, C: Employment Leadership Position: Genentech/Roche; Stock Ownership: Genentech/Roche. Hiddemann, W: Consultant Advisory Role: Roche, Janssen, Helsinn; Honoraria: Roche, Celgene, Janssen; Research Funding: Roche, Janssen, Bayer; Other Remuneration: Expenses: Janssen, Roche. Marcus, R: Consultant Advisory Role: Gilead; Honoraria: Roche; Other Remuneration: Speakers' Bureau: Roche; Expert Testimony: Gilead; Expenses: Takeda. Herold, M: Consultant Advisory Role: Janssen; Honoraria: Roche, Janssen, Gilead, Celgene; Research Funding: Roche. Salles, G: Consultant Advisory Role: Abbvie, Celgene, Gilead, Epizyme, Janssen, Karyopharm, Kite, Merck, Morphosys, Novartis, Roche, Servier, Takeda; Honoraria: Abbvie, Amgen, BMS, Celgene, Gilead, Epizyme, Janssen, Karyopharm, Kite, Merck, Morphosys, Novartis, Roche, Servier, Takeda. Mattiello, F: Employment Leadership Position: Roche. Nielsen, T: Employment Leadership Position: Roche; Stock Ownership: Roche. Mir, F: Employment Leadership Position: Roche. Venstrom, J: Employment Leadership Position: Genentech. Oestergaard, M:

Employment Leadership Position: Until end of March 2019: Hoffmann-La Roche; From 1st April 2019: Novo Nordisk.

144
PERSONALIZED PREDICTION IN DLBCL
ENABLED BY FUNCTIONAL MOUSE
GENOMICS

C.A. Schmitt<fnref n="1" /> | K. Schleich² | J. Kase² | J.R. Dörr² |

M. Hummel³ | U. Leser⁴

**Introduction:** Major efforts have been undertaken to determine novel molecular subgroups in diffuse large B-cell lymphoma (DLBCL). Despite

<footnote n="1">¹Med Campus III. Hematology and Oncology, Kepler Universitätsklinikum, Linz, Austria; ²Hematology and Oncology (CVK), Charité - Universitätsmedizin Berlin, Berlin, Germany; ³Pathology, Charité - Universitätsmedizin Berlin, Berlin, Germany; ⁴Institute for Computer Science, Humboldt Universität zu Berlin, Berlin, Germany</footnote>
their tremendous biological insights, these static “at diagnosis” classifications cannot anticipate complex response conditions such as therapy-induced senescence (TIS), and have not yet affected the clinical standard of care. A syngeneic, immune-competent mouse lymphoma model that reproduces key molecular features of human DLBCL might be instrumental to dynamically explore genetic determinants of drug responsiveness. Here, we focus on TIS in treatment outcome of mouse lymphoma models and patients diagnosed with DLBCL.

**Methods:** Gene expression-profiled primary Eμ-myc transgenic lymphomas were exposed to genotoxic therapy in vivo, and subsequently monitored in a clinical trial-like design. Lymphoma senescence capability was studied in vivo by loss- and gain-of-function genetics. Large publicly available DLBCL transcriptome datasets co-annotated with the individual patient outcome to an R-CHOP-like induction therapy were used for cross-species analyses.

**Results:** We found the Eμ-myc lymphoma platform to closely recapitulate established DLBCL subtypes related to cell-of-origin (i.e. GCB/ABC) and distinct DLBCL biologies (i.e. comprehensive consensus clusters). Mechanistically, we identified in mouse lymphomas lysine 9-trimethylated histone H3 (H3K9me3) with its modifying writer/eraser activities as a central TIS relay. Moreover, the H3K9me3 mark predicted superior treatment outcome: mice bearing lymphomas with engineered loss of the H3K9me3-essential methyltransferase Suv39h1presented with shorter PFS and OS, as observed in mice harboring genetically non-engineered lymphomas with low endogenous H3K9me3 expression. Importantly, machine-learning retrieved a 22-gene signature characterizing non-engineered lymphomas (i.e. with intact Suv39h1 alleles) as being Suv39h1-proficient-like or -deficient-like, termed “SUVAR-ness” in reminiscence of “BRCA-ness” used to describe a BRCA1/2-mutant-like status in the absence of BRCA mutations. Strikingly, a humanized version of this SUVAR-ness classifier identified DLBCL patients with superior PFS and OS already in baseline transcriptome profiles, and further marked the recently reported best-outcome Chapuy/Shipp clusters C0, C1 and C4 as SUVAR-ness/senescence capacity-enriched.

**Conclusions:** Functional in vivo-dissection of cellular senescence in mice – virtually impossible in human DLBCL material – unveiled its profound impact on long-term lymphoma control. Our work highlights the power of tractable transgenic mouse models with and without defined genetic lesions to predict individual outcome of DLBCL patients, and to further inform lesion- and state-based treatment decisions in personalized cancer precision medicine.

**Keywords:** diffuse large B-cell lymphoma (DLBCL); induction treatment; mouse models.

# 145
SAMD14/NEURABIN-I AS BCR-ANTIGENS OF PRIMARY CENTRAL NERVOUS SYSTEM LYMPHOMA

L. Thurner¹ | M. Bewarder¹ | N. Fadle¹ |

E. Regitz¹ | V. Poeschel¹ | M. Ziepert² |

R. Schuck¹ | S. Altmeyer¹ | M. Kemele¹ | T. Bock¹ |

C. Schormann¹ | S. Walter³ | M. Szczepanowski⁴ |

W. Klapper⁴ | C. Monoranu⁵ | A. Rosenwald⁵ |

P. Moeller⁶ | Y. Kim⁷ | R. Buslei⁸ |

D. Kaddu-Mulindwa¹ | F. Neumann¹ | K. Roemer¹ |

R. Bohle⁷ | G. Illerhaus⁹ | E. Schorb¹⁰ |

H. Schaefer¹⁰ | M.L. Hansmann¹¹ | S. Hartmann¹¹ |

G. Held¹ | S. Stilgenbauer¹ | N. Murawski¹ |

M. Pfreundschuh¹ | K.D. Preuss¹

¹Saarland Medical School, Internal Medicine I, José Carreras Center, Homburg/Saar, Germany; ²Universität Leipzig, Institute for Medical Informatics, Statistics, and Epidemiology, Leipzig, Germany; ³Saarland Medical School, Department of Neurology, Homburg/Saar, Germany; ⁴University of Kiel, Institute of Pathology, Hematopathology Section and Lymph Node Registry, Kiel, Germany; ⁵University of Würzburg, Institute of Pathology and Neuropathology, Würzburg, Germany; ⁶University of Ulm, Department of Pathology, Ulm, Germany; ⁷Saarland Medical School, Department of Pathology, Homburg/Saar, Germany; ⁸SozialStiftung Bamberg, Institute of Pathology, Bamberg, Germany; ⁹Klinikum Stuttgart, Department Hematology and Oncology, Stuttgart, Germany; ¹⁰University Medical Center Freiburg, Department of Hematology and Oncology, Freiburg, Germany; ¹¹Goethe University Frankfurt, Senckenberg Institute of Pathology, Frankfurt, Germany

**Introduction:** Primary central nervous system lymphoma represents a distinct subgroup of DLBCL with exclusive manifestation in the CNS, which is therefore challenging to treat. PCNSL often harbour mutations in the BCR pathway and have overrepresented IGVH4-34. Polyreactive, low affinity BCRs have been reported recently for PCNSL.

**Methods:** To address the role of chronic antigenic stimulation in primary central nervous system lymphoma, we searched for autoantigens by expression cloning of PCNSL B-cell receptors (BCRs) and subsequent screening for antigens in the spectrum of self antigens and antigens of infectious origin. Identified antigens were verified by immunoassays and analyzed for immunogenic differences in respective cases by sequencing and proteomic means. ABC type DLBCL cell lines transfected to express recombinant PCNSL BCRs were used as modell for PCNSL and the effects of addition of SAMD14/neurabin-I on BCR activation and cell proliferation were studied. Moreover targeting PCNSL BCRs was investigated as a proof of principle by using an immunotoxin comprising the common BCR binding epitope of neurabin-I conjugated to a truncated form of *Pseudomonas Exotoxin A* by cytotoxicity and apoptosis assays.

**Results:** Sterile α-motif domain containing protein 14 (SAMD14) and neural tissue-specific F-actin binding protein I (neurabin-I) were identified as autoantigenic targets of the BCRs from 8/12 PCNSLs. Neurabin-I contains a SAM domain with high homology to SAMD14. In the respective cases, SAMD14 and neurabin-I were atypically hyperN-glycosylated (SAMD14 at ASN339 and neurabin-I at ASN1277), explaining their immunogenicity. PCNSL-patients had SAMD14/Neurabin-I autoantibodies in relevant titres. Addition of SAMD14 and/or neurabin-I induced BCR pathway activation and proliferation of
aggressive lymphoma cell lines transfected with SAMD14-/ neurabin-1-reactive BCRs. Moreover, the BCR binding epitope of neurabin-1 conjugated to truncated *Pseudomonas exotoxin A* killed lymphoma cells expressing the respective BCRs.

**Conclusion:** Our results support the role of chronic antigenic stimulation by specific and posttranslationally modified autoantigens in the pathogenesis of a subgroup of PCNSL. Studies on the frequency of hyper-N-glycosylated SAMD14/neurabin-1 isoforms and of SAMD14/neurabin-1 autoantibodies in prospectively collected sera of patients from PCNSL rials are necessary to better determine the "real" proportion of the SAMD14/neurabin-1-reactive subgroup in PCNSL. Finally, different therapeutic concepts for this subgroup will be presented.

**Keywords:** B-cell receptor (BCR); immunoglobulins (Ig); primary CNS lymphoma (PCNSL).

**Disclosures:** Thurner, L: Consultant Advisory Role: MERCK; Other Remuneration: Travel Funding to Meeting: JANSSEN.

146
# POPULATION-BASED OUTCOMES IN LARGE B-CELL LYMPHOMA BY WHO SUBTYPE: FINDINGS FROM THE UK'S HAEMATOLOGICAL MALIGNANCY RESEARCH NETWORK

R. Patmore<fnref n="1" /> | A. Smith² | S. Barrans³ | D. Painter² |
D. Howell² | C. Burton³ | E. Roman²

**Introduction:** Distinct morphologic, molecular and immunophenotypic variants of large B-cell lymphoma are well recognised, but information on their outcomes in the general (non-trial) patient populations is scarce. With centralised diagnostics at HMDS, Leeds and a

unified clinical network covering a catchment population of ~4 million, the UK's population-based Haematological Malignancy Research Network (www.hmrn.org) was established to provide timely real-world data to answer such questions; and the findings are reported here.

**Methods:** All 3,357 patients newly diagnosed 2004-16 with de novo DLBCL were followed-up until January 2019 (median 7.5 years); and demographic, prognostic, treatment and outcome data were analysed.

**Results:** Median diagnostic age was 70.3 yrs, 52.7% of patients were male and 29.1% had a high IPI. DLBCL NOS predominated (87%); but clinical and demographic factors varied significantly with subtype (Table 1), as did survival (Figure 1). Patients with primary CNS DLBCL had the poorest OS (median 6 months); median survival for those with primary cutaneous DLBCL, leg type (PCLBCL) (5.6 years) was similar to DLBCL NOS (5.4 yrs), but patients with T-cell/histiocyte-rich DLBCL had better outcomes, approaching those of PMBL. DLBCL NOS patients (n = 874/2919) were further stratified by their cell-of-origin (assigned using gene-expression profiling); median OS for GCB and ABC subtypes was 8.9 and 2.5 years respectively; the latter increased to 5.5 years when adjusted for age.

Most patients were treated with intensive chemotherapy (80.3%, 94.6% received rituximab immunotherapy); the remainder received non-intensive chemotherapy, radiotherapy only, or supportive/palliative care. Of the 80% of patients who responded to first line therapy, 25% subsequently relapsed; this was highest in primary CNS DLBCL (67.4%). Around 20% of patients received second line therapy, either because of refractory disease or due to relapse; median survival in these patients was 6 months.

**Conclusions:** Our findings confirm the heterogeneity of DLBCL, the improved survival in patients with PCLBCL in the rituximab era and continued poor outcomes for plasmablastic lymphoma. Within DLBCL NOS, the distinct cell-of origin differences highlight the importance of molecular profiling in the study and therapy of this disease. Future trials aimed at improving outcomes for patients need to take account of both molecular and histological subtypes and focus on the unmet need of those with a poor prognosis.

<table><caption>TABLE 1</caption><thead><tr><th></th><th>N (%)</th><th>Median Age (years)</th><th>Male %</th><th>High IPI %</th><th>Intensive Chemotherapy %</th><th>Response %</th><th>Relapse %</th></tr></thead><tbody><tr><td>Total</td><td>3357 (100)</td><td>70.3</td><td>52.7</td><td>29.1</td><td>80.3</td><td>79.4</td><td>24.2</td></tr><tr><td>DLBCL, NOS</td><td>2919 (87.0)</td><td>71.0</td><td>51.1</td><td>30.5</td><td>79.8</td><td>80.1</td><td>23.9</td></tr><tr><td>Primary CNS (CNS DLBCL)</td><td>118 (3.5)</td><td>65.2</td><td>55.1</td><td>30.8</td><td>75.4</td><td>48.3</td><td>67.4</td></tr><tr><td>Primary testicular</td><td>96 (2.9)</td><td>71.4</td><td>100.0</td><td>13.8</td><td>89.6</td><td>88.4</td><td>21.5</td></tr><tr><td>Primary mediastinal (PMBL)</td><td>79 (2.4)</td><td>41.4</td><td>46.8</td><td>8.5</td><td>96.2</td><td>89.5</td><td>5.9</td></tr><tr><td>T-cell/histiocyte-rich (THRLCBL)</td><td>74 (2.2)</td><td>64.4</td><td>59.5</td><td>23.6</td><td>87.8</td><td>76.9</td><td>13.7</td></tr><tr><td>Plasmablastic (PBL)</td><td>38 (1.1)</td><td>68.1</td><td>60.5</td><td>25.9</td><td>68.4</td><td>61.5</td><td>56.3</td></tr><tr><td>Primary cutaneous, leg type (PCLBCL)</td><td>25 (0.7)</td><td>78.9</td><td>32.0</td><td>11.1</td><td>64.0</td><td>93.8</td><td>40.0</td></tr><tr><td>Intravascular</td><td>8 (0.2)</td><td>74.6</td><td>62.5</td><td>80.0</td><td>75.0</td><td>100</td><td>33.3</td></tr></tbody></table>

<footnote n="1">¹Queen's Centre for Oncology and Haematology, Hull University
Teaching Hospitals NHS Trust, Hull, United Kingdom; ²Health Sciences,
University of York, York, United Kingdom; ³Leeds Cancer Centre,
Haematological Malignancy Diagnostic Service, Leeds, United Kingdom</footnote>
<figure><img src="image_112.png" /><figcaption>Figure 1: Overall survival by large cell lymphoma subtype</figcaption></figure>

**Keywords:** B-cell lymphoma; diffuse large B-cell lymphoma (DLBCL); rituximab.

**Disclosures:** Patmore, R: Consultant Advisory Role: Roche. Smith, A: Research Funding: Abbvie, Gilead, Novartis. Burton, C: Employment Leadership Position: Nil; Consultant Advisory Role: Roche, Takeda, BMS, Celgene; Stock Ownership: Nil; Honoraria: Roche, Takeda, BMS; Research Funding: Nil; Other Remuneration: Nil.

147
REFINEMENT OF MUM1 EXPRESSION THRESHOLD FOR DOUBLE POSITIVE CD10 + MUM1+ DIFFUSE LARGE B CELL LYMPHOMA ALLOWS A BETTER CELL OF ORIGIN CLASSIFICATION FOR GCB SUBTYPE

C. Bossard¹ | O. Laghmari¹ | Y. Le Bris² |

A. Bonnet³ | A. Moreau¹ | W. El Alami Thomas⁴ |

A. Pavageau⁵ | P. Guerzider⁶ | H. Maisonneuve⁷ |

P. Ruminy⁸ | M. Bene² | O. Casasnovas⁹ |

D. Canioni¹⁰ | C. Thieblemont¹¹ | T. Petrella¹² |

F. Jardin¹³ | G. Salles¹⁴ | H. Tilly¹³ | P. Gaulard¹⁵ |

C. Haioun¹⁶ | J. Brière¹¹ | S. Le Gouill³ |

C. Copie Bergman¹⁵ | T.J. Molina¹⁰

¹Department of Pathology, University Hospital of Nantes, Nantes, France; ²Department of Hematology Biology, University Hospital of Nantes, Nantes, France; ³Department of Hematology, University Hospital of Nantes, Nantes, France; ⁴Pathology, IHP Group, Nantes, France;

⁵Department of Pathology, Centre Hospitalier de la Roche sur Yon, La Roche sur Yon, France; ⁶Department of Pathology, Centre Hospitalier de Saint Nazaire, Saint Nazaire, France; ⁷Department of Hematology, Centre Hospitalier de la Roche sur Yon, La Roche sur Yon, France; ⁸INSERM U918, Centre Henri Becquerel, Rouen, France; ⁹Department of Hematology, University Hospital, Dijon, France; ¹⁰Department of Pathology, Hopital Necker Enfants Malades, Paris, France; ¹¹Hematology Oncology Department, Hopital Saint Louis, Paris, France; ¹²Department of Medical Oncology, Odette Cancer Center, Toronto, Canada;

¹³Department of Hematology, Centre Henri Becquerel, Rouen, France;

¹⁴Department of Hematology, Hospice Civils de Lyon, Lyon, France;

¹⁵Department of Pathology, Groupe Hospitalier Henri Mondor, Creteil, France; ¹⁶Department of Hematology, Groupe Hospitalier Henri Mondor, Creteil, France

The cell-of-origin (COO) determination of diffuse large B cell lymphoma (DLBCL) into germinal center B-cell like (GCB) and activated B-cell like (ABC) by immunohistochemistry based on the most commonly used Hans' algorithm, has at most 86% (Meyer et al, JCO, 2011) to 91% of concordance (Petrella et al, Annals Oncol, 2017) compared with the gold standard gene-expression profiling approach. Among those discrepancies, the algorithm is giving to CD10 positivity a priority over MUM1 for assigning GCB subtype, whatever the level of expression of MUM1 above 30%. Indeed, a substantial number of cases featuring a double positive (DP) CD10+ MUM1+ phenotype are classified as GCB according to Hans' algorithm whereas ABC on gene expression profiling.

The aim of this study was to evaluate whether the expression level of MUM1 assessed by immunohistochemistry could predict the molecular classification of DP in GCB or ABC. For that purpose, we used 2 independent cohorts of patients: one with 1608 DLBCLs from LYSA trials (GHEDI Cohort, GAINED, REMARC, RT3), the other with 255 DLBCLs treated in Nantes University Hospital (CHU Nantes) between 2006 and 2016. One hundred twenty two and 22 DP DLBCLs respectively were identified in these 2 cohorts, representing

<table><caption>TABLE 1 Threshold selection among evaluable patients (excluding unclassified DLBCLs, n=73)</caption><thead><tr><th>Cut-Off (%)</th><th>Predicted Probabilities</th><th>True Positive (GC correctly identified)</th><th>True Negative (ABC correctly identified)</th><th>False Positive (ABC identified as GC)</th><th>False Negative (GC identified as ABC)</th><th>Sensitivity</th><th>Specificity</th></tr></thead><tbody><tr><td>30</td><td>0.92</td><td>10 (14.49%)</td><td>24 (34.78%)</td><td>0</td><td>35 (50.72%)</td><td>0.222</td><td>1</td></tr><tr><td>40</td><td>0.88</td><td>14 (20.29%)</td><td>24 (34.78%)</td><td>0</td><td>31 (44.93%)</td><td>0.311</td><td>1</td></tr><tr><td>50</td><td>0.82</td><td>19 (27.54%)</td><td>23 (33.33%)</td><td>1 (1.45%)</td><td>26 (37.68%)</td><td>0.422</td><td>0.958</td></tr><tr><td>60</td><td>0.76</td><td>22 (31.88%)</td><td>21 (30.43%)</td><td>3 (4.35%)</td><td>23 (33.33%)</td><td>0.488</td><td>0.875</td></tr><tr><td>70</td><td>0.68</td><td>25 (36.23%)</td><td>18 (26.09%)</td><td>6 (8.70%)</td><td>20 (28.99%)</td><td>0.556</td><td>0.75</td></tr><tr><td>80</td><td>0.56</td><td>34 (49.28%)</td><td>13 (18.84%)</td><td>11 (15.94%)</td><td>11 (15.94%)</td><td>0.756</td><td>0.542</td></tr><tr><td>90</td><td>0.46</td><td>40 (57.97%)</td><td>6 (8.70%)</td><td>18 (26.09%)</td><td>5 (7.25%)</td><td>0.889</td><td>0.25</td></tr><tr><td>100</td><td>0.34</td><td>45 (65.22%)</td><td>0</td><td>24 (34.78%)</td><td>0</td><td>1</td><td>0</td></tr></tbody></table>
8% of DLBCLs. RNA extracted from FFPE tissues was available for 91 DP DLBCLs, tested for gene expression profiling by the RT-MLPA assay, a sensitive method validated on archival paraffin-embedded formalin-fixed (FFPE) tissues for the GCB/ABC classification (Bobee et al, J Mol Diagn, 2017). The level of MUM1 expression by 10% increments was evaluated on those 91 cases by three pathologists on multihead microscope. Among the 81 DP DLBCLs with available results (5 failures, 2 DLBCL EBV+ and 3 PMBL) for GCB/ABC classification by RT-MLPA, 48 cases (59.2%) were classified in GCB molecular subtype, 25 (30.8%) in ABC and 8 were unclassified (9.8%).

In order to correctly identify GCB molecular DP DLBCLs based on
Hans' algorithm, depending on MUM1+ tumor cells, we tested differ-
ent MUM1 thresholds (Table 1). A MUM1 threshold ≤ 50% correctly
identified 19/48 molecular GCB and misclassified only 1 ABC (speci-
ficity 95%), while higher thresholds could not reliably identify GCB or
ABC DLBCL.

Overall, our study clearly demonstrates that Hans' algorithm cannot
be used to accurately identify molecular GCB and ABC DLBCL within
the DP CD10+MUM1+ except when MUM1+ tumor cells do not
exceed 50%. This new threshold could be included in the Hans' algo-
rithm to identify GCB DLBCLs among DP DLBCLs. Above this thresh-
old, targeted gene expression tests should be used to correctly
classify these subgroups of DLBCLs for COO.

**Keywords:** diffuse large B-cell lymphoma (DLBCL).

148
REDUCED BCL2 EXPRESSION SUGGESTS ALTERNATIVE SURVIVAL MECHANISMS IN HIV(+) DIFFUSE LARGE B CELL LYMPHOMA (DLBCL) OF GERMINAL CENTER ORIGIN

A. Maguire¹ | X. Chen² | L. Wisner¹ | S. Malasi¹ |

C. Ramsower¹ | S. Kendrick³ | M.T. Barrett¹ |

B. Glinsmann-Gibson¹ | M. McGrath⁴ | L. Rimsza⁵

¹Research, Mayo Clinic, Scottsdale, AZ, United States; ²Research Biostatistics, Mayo Clinic, Scottsdale, AZ, United States; ³Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, United States; ⁴Laboratory Medicine and Pathology, University of California, San Francisco, CA, United States; ⁵Laboratory Medicine and Pathology, Mayo Clinic, Phoenix, AZ, United States

**Introduction:** DLBCL is more aggressive in HIV infected individuals compared to the general population. RNAseq studies showed DLBCL to be comprised of two key Cell of Origin (COO) subtypes with distinct survival profiles post therapy; namely GCB (germinal center B-cell like) and ABC (activated B-cell like). The Lymph2Cx clinical diagnostic assay for COO subtyping was recently developed for use with FFPE tissues. To date, accurate investigation of HIV related DLBCL by COO has not been done. In this study we examined the genomic and transcriptional differences between HIV(+) and HIV(-) GCB-DLBCL, defined using the Lymph2Cx assay, to better understand the

molecular mechanisms underlying the enhanced aggressive nature of
HIV related DLBCL.

**Methods:** A total of 40 cases, including 19 HIV(+) GCB-DLBCL cases from the AIDS Cancer Specimen Resource Network (https://acsr.ucsf.edu/) and 21 HIV(-) GCB DLBCL institutional cases were included in this study. H&Es were reviewed by a hematopathologist to validate diagnosis and determine tumor content. Samples were macro-dissected up to minimal tumor content by area of ≥60%. Two 10 µm FFPE sections per sample were DNA/RNA extracted. DNA was used for copy number variant (CNV) analysis using Agilent array CGH. Protein expression was assessed by IHC. RNA was used to perform COO subtyping using the Lymph2Cx assay, and gene expression profiling (GEP) using the NanoString Pan-Cancer Pathways panel.

**Results:** Significant differences were observed between the HIV(+) and HIV(-) GCB-DLBCL cohorts. Although CNV analysis revealed both cohorts to be predominately diploid at the *BCL2* locus, when aberrations did occur, they were exclusively losses/deletions in the HIV(+) cohort and exclusively gains/amplifications in the HIV(-) cohort. These results were highly concordant with BCL2 protein expression; where those with losses/deletions had low BCL2 expression, while those with gains/amplifications had high BCL2 expression. Overall, the HIV(+) cohort had significantly reduced BCL2 expression at both the transcriptional (p<0.001) and protein level (p = 0.0194). Intriguingly, the HIV(+) cohort was also found to be significantly more proliferative by Ki67 staining (p = 0.008), with significantly reduced gene expression of cell cycle inhibitors (CDKN1A, CDKN1B, p≤0.025). In fact an inverse relationship was found between the proliferation marker Ki67 and BCL2 by IHC in samples with *BCL2* gene aberrations. Reduced expression of key pro-apoptotic *BCL2-genes* (BAX, *BIM*, *BMF*, *PUMA*) was also observed in the HIV(+) cohort (p≤0.027).

**Conclusions:** BCL2 is a known negative prognostic marker in DLBCL. Reduced expression of BCL2 and of other pro-apoptotic BCL2 family genes in HIV(+) DLBCL, as well as cell cycle inhibitors, suggests a reduced dependence on the pro-survival effects of BCL2 and a switch to a mechanism that depends on preventing cycle inhibition and the induction of apoptosis.

**Keywords:** BCL2; diffuse large B-cell lymphoma (DLBCL); human immunodeficiency virus (HIV).

149
SINGLE CELL LEVEL ANALYSIS OF MYC/
BCL2/ BCL6 CO-EXPRESSION IN DIFFUSE
LARGE B-CELL LYMPHOMA THROUGH
MULTIPLEXED QUANTITATIVE
IMMUNOFLUORESCENCE

L.M. Poon¹ | M.M. Hoppe² | S. Fan³ | S.N. Choo¹ |

H.W. Choi⁴ | L. Xin¹ | S. De Mel¹ | E. Chan¹ |

J. Lee¹ | Y.L. Chee¹ | W.J. Chng¹ | S.B. Ng² |

A.D. Jeyasekharan²
¹Department of Haematology-Oncology, National University Hospital of Singapore, Singapore, Singapore; ²Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore; ³Department of Pathology, National University of Singapore, Singapore, Singapore; ⁴Saw Swee Hock School of public health, National University of Singapore, Singapore, Singapore

**Introduction:** MYC, BCL2 and BCL6 are commonly used markers for immunohistochemistry of DLBCL, providing prognostic information for outcome. Co-expression of MYC and BCL2 in particular constitute a subgroup of "double expressor lymphomas" with a distinct clinical outcome. However, it is not known if MYC and BCL2/BCL6 co-expression occurs in the same cell or in different cells within the tumour, as traditional immunohistochemical approaches are limited by the number of markers that can be simultaneously assessed within formalin-fixed paraffin embedded (FFPE) samples. In this study we have used multiplexed quantitative immunofluorescence (qIF) to concurrently study MYC and BCL2/BCL6 expression in DLBCL.

**Methods:** 130 cases of DLBCL, treated with R-CHOP chemotherapy and annotated clinical data (n = 90) were included in this study. The samples were arrayed on a Tissue Microarray (TMA). Multiplexed immunofluorescence for MYC/ BCL2/ BCL6/ Ki67 and CD20 was performed on single TMA slides using the sequential OPAL-TSA method. The slides were imaged using the Vectra 3 system, and unmixed to yield monochrome single colour images of each marker. The relative intensity of each marker per cell was then quantified using the InFORM software. Further statistical analyses were performed using graphpad prism and R.

**Results:** qIF was able to simultaneously measure MYC, BCL2, BCL6 and Ki67 in CD20 positive cells within a single DLBCL TMA slide. Only a subset of cells within the population expressed multiple markers concurrently. A probability-based co-localization algorithm shows that MYC and BCL2 co-localize largely along a probabilistic pattern, while MYC-BCL6 and Ki67 co-localize more often than predicted by probability alone. Unsupervised clustering of cases based on single markers and multiple co-localization values yielded 4 distinct subsets of DLBCL with variable clinical outcomes.

**Conclusion:** Multiplexed qIF demonstrates that only a subset of cells within a MYC-BCL2 "double expressor" lymphoma actually demonstrate colocalization at the single cell level, unlike with MYC-BCL6-KI67. The difference between MYC-BCL2 and MYC-BCL6 co-expression in terms of clinical outcome may therefore be a reflection of increased clonal heterogeneity within the tumour for cells expressing these oncogenes.

**Keywords:** BCL2; diffuse large B-cell lymphoma (DLBCL); MYC.

150
CLINICAL SIGNIFICANCE OF T-CELL
EXHAUSTION IN PATIENTS WITH DIFFUSE
LARGE B-CELL LYMPHOMA

S. Leppä¹ | M. Autio¹ | O. Brück² | S. Mustjoki² |

J. Jørgensen³ | M. Karjalainen-Lindsberg⁴ | K. Beiske⁵ |

H. Holte⁶ | T. Pellinen⁷ | S. Leivonen¹

¹Department of Oncology and Applied Tumor Genomics Research Program, Helsinki University Hospital Comprehensive Cancer Centre and University of Helsinki, Helsinki, Finland; ²Hematology Research Unit and Translational Immunology Research Program, Helsinki University Hospital Comprehensive Cancer Centre and University of Helsinki, Helsinki, Finland; ³Department of Hematology, Aarhus University Hospital, Aarhus, Denmark; ⁴Department of Pathology, Helsinki University Hospital, Helsinki, Finland; ⁵Department of Pathology, Oslo University Hospital, Oslo, Norway; ⁶Department of Oncology, Oslo University Hospital, Oslo, Norway; ⁷Systems Biomedicine, Institute for Molecular Medicine Finland, Helsinki, Finland

**Introduction:** Tumor microenvironment (TME) and limited immune surveillance play important role in lymphoma pathogenesis and survival. Immune checkpoint receptors, such as programmed cell death-1 (PD1), lymphocyte-activation gene-3 (LAG3) and T-cell immunoglobulin and mucin domain-3 (TIM3), mediate signals leading to T-cell exhaustion and immune escape. Here, we have characterized the immunological profiles of diffuse large B-cell lymphoma (DLBCL) and associated the findings with outcome.

**Methods:** Gene expression analysis was conducted for 81 DLBCL samples utilizing the NanoString platform with a 770-gene PanCancer Immune panel. Multiplex immunohistochemistry (mIHC) with digital image analysis was used to characterize the T-cell phenotypes, including cytotoxic T-cells (CD8, GrB, OX40, Ki67), exhausted T-cells (CD3, CD4, CD8, PD1, TIM3, LAG3), Tregs and Th1 effector cells (CD3, CD4, FOXP3, TBET) of a total of 225 DLCBL samples. The findings were associated with patient demographics and survival and clinical significance validated in an independent patient cohort.

**Results:** We observed a high degree of heterogeneity in transcriptome level among the DLBCL samples. Correlation matrix analysis identified gene expression signatures with highly correlating genes. The main signatures contained genes for cytolytic factors and immune checkpoint molecules (GZMB, PRF1, IFNG, TIM3, LAG3) and T-cells (CD3, CD2, CD28), together entitled as a T-cell signature, macrophages (CD68, CD163), B-cells (MS4A1, CD19, CD79A/B), and extracellular matrix (FN1, ITGA1/5/6, VEGFA). None of the gene expression signatures as such were associated with survival. However, immunophenotyping of the distinct T-cell subsets with mIHC revealed that a high proportion of exhausted T-cells (TIM3+ and/or LAG3+) was associated with unfavorable survival in a cohort of 51 young high risk DLBCL patients treated in a Nordic phase II (NLG-LBC-05) trial with dose-dense immunochemotherapy and systemic CNS prophylaxis (5-year OS 73% vs. 96%, p = 0.022 and 5-year PFS 74% vs. 93%, p = 0.064). In contrast, the number of cytotoxic T cells, Tregs or Th1 effector cells did not correlate with outcome. The adverse prognostic impact of exhausted T-cells on survival was validated in an independent cohort of 137 DLBCL patients treated with immunochemotherapy
(5-year OS 66% vs. 79%, p = 0.029 and 5-year PFS 60% vs. 76%, p = 0.035).

**Conclusions:** Our results demonstrate that the molecular immunological profile of DLBCL is heterogenic and that putative markers of T-cell exhaustion associate with unfavorable survival in patients with DLBCL.

**Keywords:** diffuse large B-cell lymphoma (DLBCL); immunophenotype; T-cells.

151
THE INFLUENCE OF TUMOR IMMUNE MICROENVIRONMENT AND TUMOR IMMUNITY ON THE PATHOGENESIS, TREATMENT AND PROGNOSIS OF POST-TRANSPLANT LYMPHOPROLIFERATIVE DISORDERS (PTLD)

H. Saito¹ | H. Shibayama¹ | H. Miyoshi² | J. Toda¹ |

S. Kusakabe¹ | M. Ichii¹ | J. Fujita¹ |

K. Fukushima¹ | T. Yokota¹ | T. Maeda¹ |

M. Mizuki¹ | K. Oritani³ | M. Seto² | K. Ohshima² |

Y. Kanakura¹

¹Department of Hematology and Oncology, Osaka University Graduate School of Medicine, Osaka, Japan; ²Department of Pathology, Kurume University School of Medicine, Kurume, Japan; ³Department of Hematology, International University of Health and Welfare, Narita, Japan

**Introduction:** PTLD is a heterogeneous group of abnormal lymphoid proliferations occurring in the immunosuppressed recipients of solid organ transplant (SOT) or bone marrow transplant. Epstein-Barr virus infection is considered as one of the major risk factors of PTLD. Although the relationship between PTLD pathogenesis and tumor immune microenvironment (TIME) is still unclear, it is well known that the PD-1/PD-L1 pathway and regulatory T cells attenuate anti-tumor response of cytotoxic T lymphocytes (CTLs) in other tumors. We have

recently shown that PD-L1 expression is associated with poor prog-
nosis in DLBCL and ATLL. Furthermore, reduction of immunosuppres-
sants (RIS) and/or rituximab (RTX) are considered as the first-line
therapy in PTLD patients, although it is not clear which group of
patients responds to RIS/RTX. The aim of this study is to elucidate
the influence of TIME on the pathogenesis, treatment, and prognosis
of PTLD.

**Methods:** We retrospectively analyzed 26 consecutive patients with PTLD who were diagnosed and treated at our institution between 2006 and 2016. We examined FFPE samples using immunohistochemistry and in situ hybridization. Degree of immunosuppression was classified into three groups, strong: use of three or more immunosuppressants or high calcineurin inhibitor (cyclosporine > 200 ng/mL or tacrolimus > 8 ng/mL), none: no use of immunosuppressants, and intermediate: moderate use of immunosuppressants.

**Results:** The median age was 43 years, 61% patients received SOT, median time from transplant to PTLD development was 12 months, and 70% patients were DLBCL type. Patients who developed PTLD soon after transplantation had significantly more PD-1+ tumor infiltrating lymphocytes (TILs) (p = 0.0039) (Fig. 1). Furthermore, most of them were positive for EBER. In EBER negative patients, a large number of PD-1+ TILs were observed. Multivariate analysis with the number of PD-1+ TILs and EBER positivity showed that high number of PD-1+ TILs remained a significant factor for early-onset of PTLD in all patients and in DLBCL type patients (p = 0.0012 and p = 0.0030, respectively). Among 18 patients who received RIS/RTX for the first line treatment, overall response rate (ORR) was lower in the patients received strong immunosuppressants than in those received intermediate and no immunosuppressants (22% vs. 100% and 100%, respectively; p = 0.0029). Similar results were also found in 12 DLBCL type patients (p = 0.0073). Time to progression (TTP) was relatively less in the patients with FoxP3+ TILs and significantly less in DLBCL type patients with FoxP3+ TILs (p = 0.069 and p = 0.011, respectively).

**Conclusions:** This study revealed that high number of PD-1+ TILs was an important factor responsible for early-onset PTLD; strongly immunosuppressed patients exhibited lower ORR in RIS/RTX therapy, and

<figure><img src="image_113.png" /><figcaption>Fig. 1 Association of the number of PD-1+ TILs with PTLD onset</figcaption></figure>
DLBCL type patients with FoxP3+ TILs exhibited significantly less TTP. These results suggested that TIME plays a vital role in pathogenesis, treatment, and prognosis of PTLD.

**Keywords:** post-transplant lymphoproliferative disorders (PTLDs).

## 152 JAK-STAT PATHWAY AND EPIGENETIC REGULATORS ARE CRITICAL PLAYERS IN BI-ALCL PATHOGENESIS?

C. Laurent¹ | A. Nicolae² | C. Laurent³ |

F. Le Bras⁴ | C. Haioun⁵ | V. Fataccioli⁶ |

N. Amara¹ | J. Adélaïde⁷ | A. Guille⁷ |

J. Schiano De Colella⁸ | B. Tesson³ |

A. Traverse-Glehen⁹ | M. Chenard² | L. Mescam¹⁰ |

A. Moreau¹¹ | C. Chassagne-Clément¹² | J. Somja¹³ |

F. Escudié¹ | M. André¹⁴ | N. Martin¹⁵ |

A. Hamy-Petit¹⁶ | F. Reyal¹⁷ | M. Croix³ |

D. Birnbaum⁷ | P. Brousset¹ | L. Xerri¹⁸ | P. Gaulard⁶

¹Pathology Department, Institut Universitaire du Cancer Oncopole CHU Toulouse INSERM U1037, Toulouse, France; ²Pathology, Hôpital de Hautepierre, Strasbourg, France; ³CALYM - LYSARC, Institut Carnot, Pierre-Bénite, France; ⁴Lymphoid Malignancies Unit, AP-HP, Groupe Hospitalier Henri Mondor - Albert Chenevier, Créteil, France; ⁵Lymphoid Malignancies Unit, AP-HP, Groupe Hospitalier Henri Mondor-Albert Chenevier, INSERM U955, Université Paris-Est, Créteil, France;

⁶Department of Pathology, AP-HP, Groupe Hospitalier Henri Mondor-Albert Chenevier, INSERM U955, Université Paris-Est, Créteil, France;

⁷Department of Predictive Oncology, Centre de Recherche en Cancérologie de Marseille (CRCM), Inserm U1068, CNRS UMR7258, Aix-Marseille University, UM 105, Institut Paoli-Calmettes, Marseille, France;

⁸Hematology, Institut Paoli-Calmettes, Marseille, France; ⁹Pathology Department, Hospices Civils de Lyon, Centre Hospitalier Lyon-Sud, Pierre-Bénite, France; ¹⁰Department of Bio-Pathology, Institut Paoli-Calmettes, Marseille, France; ¹¹Pathology, CHU Nantes, Nantes, France;

¹²Pathology, Centre Léon Bérard, Lyon, France; ¹³Pathology and Cytology Department, CHU de Liège, Liège, Belgium; ¹⁴Hematology, CHU UCL Namur, Yvoir, Belgium; ¹⁵IMRB - Institut Mondor de Recherche Biomédicale, INSERM U955, Créteil, France; ¹⁶Residual Tumour & Response to Treatment Laboratory, RT2Lab, INSERM, U932, PSL

Research University, Translational Research Department, Institut Curie, Paris, France; ¹⁷Department of Surgical Oncology, Institut Curie, Paris, France; ¹⁸Department of Bio-Pathology and Tumor Immunology, Aix-Marseille University, Centre de Recherche en Cancérologie de Marseille (CRCM), Institut Paoli-Calmettes, Marseille, France

**Background:** Breast Implant-associated anaplastic large cell lymphoma (BI-ALCL) is a rare T-cell lymphoma arising in association with breast implant, particularly those with textured surfaces. We recently identified two histopathological BI-ALCL subtypes: in-situ and tumor-type which correlated with the seroma vs tumor mass clinical presentation, respectively. Although genetic events involving the JAK/STAT

pathway have been reported and the putative role of local chronic inflammation has been suspected, BI-ALCL pathogenesis remains elusive. To further explore potential molecular mechanisms involved in the pathobiology of these two distinct BI-ALCL subtypes, we performed a genomic characterization of 34 such cases.

**Patient and Methods:** Fifty-four BI-ALCL patients have been diagnosed through the *Lymphopath* network and registered in the Lymphoma Study Association Registry from 2010 to 2018. A total of 34 BI-ALCL samples have been analyzed by whole exome sequencing (WES) (n = 22 paired tumor/ germline DNA) and/or targeted next generation sequencing (NGS) (n = 24), across 406 genes to validate the findings. The average depth of sequencing was 300x for WES and 500x for targeted NGS.

**Results:** Fifty nine percent of cases (20/34) showed mutations in at least one member of the JAK/STAT signaling pathway. STAT3(38%) and JAK1 (18%) were the most mutated genes whereas STAT5B (n = 1) and the negative regulators SOCS3 (n = 2), SOCS1 (n = 1) and PTPN1 (n = 1) were seldom mutated. Fifteen percent of cases harbored simultaneous mutations in two genes of this pathway. STAT3 mutations were more frequent in tumor-type than in-situ BI-ALCL (p = 0.0078). Recurrent mutations in epigenetic modifiers were seen in 70% of cases with KMT2C (26%), CHD2 (15%), CREBBP (15%) and KMT2D (9%) being the most frequently mutated genes. Loss of function mutations in TP53 (12%) have also been identified. Genomic alterations in genes involved in lymphocytes development such as EOMES and in PI3K-AKT and MAP cascades were also seen in 23.5%, 12% and 9% BI-ALCL cases, respectively. In addition, CNV analysis in 8 cases identified recurrent deletions on chromosomes 8q, 15p and 20. Furthermore, by this approach additional alterations in SOCS3 (2/8), SOCS1 (1/8), PTPN1 (6/8) and STAT5B (3/8) as well as LOH in several epigenetic regulators such as TET2 (3/8) and HDAC8 (2/8) were seen.

**Conclusions:** This large series strongly reinforce the hypothesis that dysregulation of cytokine receptor signaling caused by recurrent mutations in the JAK/STAT pathway is a key event in BI-ALCL pathogenesis. Furthermore, our observation of frequent mutations in chromatin remodeling genes highlights the importance of epigenome and provides new insights into the complexity of BI-ALCL oncogenesis.

**Keywords:** anaplastic large cell lymphoma (ALCL); epigenetics; JAK/STAT.

## 153 SPECIFIC GENETIC ALTERATIONS CHARACTERIZE SEROMA- AND TUMOR-TYPE BREAST-IMPLANT ASSOCIATED ANAPLASTIC LARGE CELL LYMPHOMA (BIA-ALCL) AS A DISTINCT DISEASE ENTITY

B. Ylstra¹ | G.T. Los-de Vries¹ | M. de Boer² |

E. van Dijk¹ | P. Stathi¹ | N. Hijmering³ |

M. Roemer¹ | M. Mendeville¹ | J. de Boer⁴ |

H. Rakhorst⁵ | F.E. van Leeuwen⁶ |

R.R. van der Hulst² | D. de Jong³
¹Pathology/Tumor Genome Analysis Core, AmsterdamUMC/VUMC, Amsterdam, Netherlands; ²Plastic, Reconstructive and Hand-Surgery, Maastricht University Medical Centre, Maastricht, Netherlands;

³Pathology, AmsterdamUMC, Amsterdam, Netherlands; ⁴Medical Oncology, Netherlands Cancer Institute, Amsterdam, Netherlands;

⁵Plastic, Reconstructive and Hand Surgery, Medisch Spectrum Twente, Enschede, Netherlands; ⁶Epidemiology and Biostatistics, Netherlands Cancer Institute, Amsterdam, Netherlands

**Background:** Breast Implant-Associated Anaplastic Large Cell Lymphoma (BIA-ALCL) is a distinctive clinical subtype in the family of ALCL. In most patients, BIA-ALCL remains confined to the periprosthetic seroma space (seroma-BIA-ALCL), while a mass in the capsule or breast tissue is seen in approximately 20% (tumor-BIA-ALCL). Seroma-BIA-ALCL can be adequately treated with explantation and capsulectomy resulting in 5 year survival of ≥ 90%. In tumor-BIA-ALCL systemic chemotherapy is required, and in rare cases, women may die of disseminated disease. As we previously showed in a population-based study, women with breast implants have a more than 400 times increased risk to develop breastALCL than women without breast implants with a life-time risk of 1:7000.

Data on molecular tumor characteristics for BIA-ALCL is limited and largely refer to activation of the JAK-STAT signaling pathway by mutations and other mechanisms, presumably epigenetic and regulatory factors. The common ALCL-related translocations have also been convincingly demonstrated to be absent. No specific molecular characteristics that distinguish BIA-ALCL from other subtypes of ALCL have been identified.

**Methods:** From the Dutch BIA-ALCL cohort of all BIA-ALCL cases diagnosed in the Netherlands between 1990 to 2017 (n = 50), we selected BIA-ALCL tumor (n = 16) and seroma (n = 19) FFPE samples of 29 patients. We performed shallow whole genome sequencing (sNGS) in these samples and in 7 cases with not-implant-associated ALCL in the breast to identify copy number aberrations (CNAs). Whole Exome Sequencing (WES) was performed for 4 tumor-BIA-ALCL and 3 seroma-BIA-ALCL cases with normal germline tissue available.

**Results:** Copy number losses of chromosomes 20, 2p and 15q were found at significantly higher frequency in BIA-ALCL compared to nodal- and cutaneous-type ALCL. The most frequent aberration for both seroma-BIA-ALCL and tumor-BIA-ALCL, loss of a 3Mb chromosomal region 20q13.12-q13.13 was found in 19/29 (65.5%) patients with a minimal common lost region spanning 20q13.12-q12.2. A considerably higher genome instability level was observed for seroma-BIA-ALCL compared to tumor-BIA-ALCL with features of complex subclonality. A significant higher frequency of loss at chromosomes 4, 8p and 15q in seroma-BIA-ALCL was seen. We observed an overall high mutational load in tumor-BIA-ALCL, while mutational load in seroma-BIA-ALCL was low. The majority of recurrent mutations were identified in the IL6-JAK1-STAT3 pathway as previously reported.

**Conclusions:** Chromosome 20 loss distinguishes BIA-ALCL from other ALCL subtypes, providing a distinctive differential diagnostic

parameter. Progression from seroma-BIA-ALCL to tumor-BIA-ALCL may be mediated by a pool of subclones driven by retention of chromosome 4q, 8p and 15q, while upon progression to tumor-BIA-ALCL the process becomes dominantly mutation-driven.

**Keywords:** anaplastic large cell lymphoma (ALCL); deep sequencing; extranodal lymphomas.

154
WHOLE GENOME SEQUENCING REVEALS POTENTIAL THERAPEUTIC STRATEGY FOR MEITL

D. Huang¹ | J. Lim¹ | K. Binte Mohd Kahliab¹ |

T. Tang² | W. Pang¹ | Y. Laurensia¹ | D. Cheah¹ |

S. Tan³ | X. Zhang⁴ | E. Chow⁴ | S. Lim² | C. Ong¹

¹CMR, National Cancer Centre, Singapore, Singapore; ²DMO, National Cancer Centre, Singapore, Singapore; ³Pathology, National University of Singapore, Singapore, Singapore; ⁴Pharmacology, Cancer Science Institute, Singapore, Singapore

**Introduction:** Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is a rare malignancy accounting for majority of intestinal T-cell lymphoma in Asia. MEITL are highly aggressive malignancy with a dismal overall survival while there currently is no effective treatment for this disease. However, the rarity of MEITL poses challenges in trying to improve clinical outcome with clinical trials. Therefore, there is an urgent need to establish a well-characterized and clinical relevant MEITL *in vitro* and *in vivo* model to decipher the biological meaning of genetic alterations, and to exploring the potential therapeutic targets.

**Methods:** Whole-genome sequencing (WGS) was performed on four MEITL tumors and corresponding blood samples. All sequencing reads were aligned with BWA-MEM. Somatic short-variants were called by Strelka2 and annotated by Annovar. Somatic structural rearrangements were called by MantaSV and annotated by AnnotSV. Simultaneously, a subcutaneous and orthotropic patient derived xeno-graft (PDX) model was also established. The PDX model was fully characterized histologically and genetically up to 6 passages. The cytotoxic/cytostatic effect of drugs targeting frequent METIL mutations was evaluated *in vitro* and *in vivo*.

**Results:** WGS analysis showed that somatic short-variant calling called out an 1.52 variants per Mb. A total of 338 non-silent protein-coding mutations were predicted, and recurrent oncogenic mutations were validated in CREBBP, STAT5B, SETD2, GNAI2 and JAK3. Mutational spectrum analysis revealed clock signature to be the dominant signature within our cohort. Somatic structural rearrangement analysis revealed clustered structural breakpoints to the locality of MYC. The histological analysis demonstrated high similarity in the overall immunomorphologic features between the primary tumour and PDX tumors: all the PDX tumors were CD3+CD4-CD8+CD56+ and extensive nuclear expression of MATK. Sanger sequencing rediscovered
83 out of 86 somatic mutations in the 6th passage of our xenografts, suggesting that the generated PDX tumors were genetically stable. Moreover, WES results showed that the clonal architecture in primary tumor was also well preserved in the PDX tumors. We observed the PDX model by chance bearded the most frequent MEITL related driver mutations, including STAT5B, SETD2, CERBBP and which are all targetable with inhibitors, i.e., pimozide, AZD1775 and romidepsin. The *in vitro* and *in vivo* experiments demonstrated a wide range of sensitivities to these three inhibitors. The most effective inhibitor is romidepsin (*In vitro* IC₅₀: 13nM; *In vivo*, 1mg/kg once per week), which has been approved by FDA for the CTCL treatment. The QPOP analysis results further showed that romidepsin had great synergistic effect with pimozide (CI: 0.45).

**Conclusions:** These results showed that the key driver mutations in MEITL are targetable and the combined targeted therapy might achieve a higher efficacy for MEITL treatment.

**Keywords:** enteropathy associated T-cell lymphoma (EATL); JAK/STAT; romidepsin (RD).

155
WHOLE-GENOME SEQUENCING REVEALS
IMMUNOTHERAPEUTIC OPTIONS FOR
NATURAL-KILLER/T CELL LYMPHOMA
PATIENTS

J. Lim<fnref n="1" /> | D. Huang<fnref n="1" /> | T. Tang² | Q. Cai³ |
D. Tan⁴ | Y. Laurensia<fnref n="1" /> | B. Chia<fnref n="1" /> | P. Rou-Jun³ |
W. Pang<fnref n="1" /> | D. Cheah<fnref n="1" /> | C. Ng⁵ | H. Hong³ |
J. Tan⁵ | L. Feng³ | J. Chen³ | B. Han³ |
Y. Guo³ | Y. Goh⁶ | O. Rötzschke⁷ | C. Cheng⁸ |
R. Au-Yeung⁹ | T. Chan⁹ | S. Ng¹⁰ | Y. Kwong⁹ |
W. Hwang¹¹ | W. Chng¹² | T. Tousseyn¹³ |
P. Tan¹⁴ | B. Teh¹¹ | C. Khor¹⁵ | S. Rozen¹⁶ |
J. Bei³ | T. Lin³ | S. Lim² | C. Ong<fnref n="1" />

Stem Cell Biology, Duke-NUS Graduate Medical School, Singapore, Singapore; ¹⁵Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, Singapore; ¹⁶Centre for Computational Biology, Duke-NUS Graduate Medical School, Singapore, Singapore

**Introduction:** Natural-killer/T cell lymphoma (NKTL) is an uncommon and aggressive malignancy with a predilection for Asian, Mexican and South American populations. Currently, no published studies have used whole-genome sequencing (WGS) to study NKTL. With the aim of exploring the NKTL tumor genomes for actionable pathways, we used WGS to study the somatic genomic landscape of NKTL.

**Methods:**

**Study Design:** Patients were diagnosed with NKTL according to the 2008 World Health Organization classification with cytotoxic, CD3ε+ and EBER+ phenotypes. All subjects in this study provided written informed consent.

**Somatic analysis:** All analysis was based on the human reference genome hs37d5. Alignment was performed by BWA-MEM. Somatic short-variant calling and annotation were done by Strelka2 and wAnnovar, respectively. Somatic copy number analysis was performed by CNVkit. Somatic structural analysis and annotation were performed by MantaSV and AnnotSV. Somatic mutational signatures analysis were performed with Non-negative factorization package.

**Results:** An average of 39 (range: 1 – 80) somatic non-silent protein-coding variants per sample was identified. Our bioinformatics analysis has also reidentified recurrent non-silent short variants in TP53, DDX3X, STAT3, FAT4 and JAK3. These observations suggest similar pathology between previously studied cohorts and our study cohorts.

Non-negative factorization also defined 4 robust mutational signatures, including 'COSMIC Signature 5' that has been reported in many cancer types, APOBEC 'COSMIC Signature 2', Oxidative Stress 'COSMIC Signature 18' and MUTYH-associated 'COSMIC Signature 17'. A predominant mutational signature to represent each sample and 'COSMIC Signature 5' was found to dominate NKTL samples (n = 21) as compared the other mutational signatures.

Somatic structural rearrangements analysis found frequent disruptions (n = 8, 25%) to the 3'UTR of PD-L1 and not of the PD-L2 gene. PD-L1 was found to be more frequently altered than other known commonly mutated genes such as DDX3X, STAT3, and JAK3 as reported in other studies. This makes PD-L1 the most frequent mutated gene in NKTL.

We have previously reported the association of PD-L1 SR with durable response to PD-1 blockade therapy in relapsed/refractory NKTL patients. However, the extent of treatment effect and the mechanisms of response/resistance to PD-1 blockade in the treated patients still remains to be elucidated. To summarize, this study reveals that a large proportion of NKTL patients could very well benefit from PD-1 blockade therapy.

<footnote n="1">¹Cellular Molecular Research, National Cancer Centre Singapore, Singapore, Singapore; ²Division of Medical Oncology, National Cancer Centre Singapore, Singapore, Singapore; ³State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, China; ⁴Raffles Cancer centre, Raffles Hospital, Singapore, Singapore; ⁵Division of Medical Sciences, National Cancer Centre Singapore, Singapore, Singapore; ⁶Department of Haematology, Singapore General Hospital, Singapore, Singapore; ⁷Agency for Science, Technology and Research, Singapore Immunology Network, Singapore, Singapore; ⁸Department of Pathology, Singapore General Hospital, Singapore, Singapore; ⁹Department of Medicine, The University of Hong Kong, Hong Kong, Hong Kong; ¹⁰Department of Pathology, National University Cancer Institute of Singapore, Singapore, Singapore; ¹¹Director Office, National Cancer Centre Singapore, Singapore, Singapore;
¹²Department of Haematology-Oncology, National University Cancer Institute of Singapore, Singapore, Singapore; ¹³Department of Imaging and Pathology, KU Leuven, Leuven, Belgium; ¹⁴Division of Cancer and</footnote>
**Conclusion:** We reported the whole-genome mutational profiles of NKTL patients using WGS data, which uncovered a large extent of genomic alterations in immune checkpoint related genes.

**Keywords:** non-Hodgkin lymphoma (NHL); PD-1.

## 156 KIR3DL2 MUTATION MAY DEFINE A HIGH RATE OF RESPONSE OF AITL TO TIPIFARNIB

A. Gualberto<fnref n="1" /> | C. Scholz<fnref n="1" /> | V. Mishra<fnref n="2" /> | L. Kessler<fnref n="2" /> | M. Rodriguez<fnref n="3" /> | M. Piris<fnref n="3" /> | T. Witzig⁴

**Introduction:** We have previously shown that Angioimmunoblastic T-cell Lymphoma (AITL) overexpresses CXCL12 and that patients (pts) with CXCL12-overexpressing T-lymphomas, including AITL, experience a high rate of response to the farnesyltransferase inhibitor tipifarnib (50% ORR, 90% clinical benefit rate, Witzig ASH 2018). Killer-cell immunoglobulin-like receptors (KIRs) are transmembrane glycoproteins expressed in NK and T cells that play regulatory functions, including roles in the regulation of chemokine/cytokine release (KIR3DL2) and angiogenesis (KIR2DL4). KIRs may be activatory (KIR-DS) or inhibitory (KIR-DL), interact with HLA and other ligands through extracellular D1-D3 loops, and signal intracellularly through ITAM (KIR-DS) or ITIM (KIR-DL) motifs.

**Methods:** Twenty-seven pretreatment biopsies from pts with relapsed or refractory peripheral T-cell lymphomas enrolled in a multi-institutional, single-arm, open-label, phase 2 study of tipifarnib were investigated using next generation whole exome sequencing and single nucleotide variations (SNVs) analyzed according to the primary study endpoint of objective response. Tumor CXCL12 and CXCR4 expression were determined by RNA Seq. Pts had received at least one prior cytotoxic systemic therapy, were ≥18 years old, and with performance status of 0-2. Clinical trial information: NCT02464228.

**Results:** A high rate of inhibitory KIR mutation (SNV of expected maximal population frequency <1%) was observed in the 11 AITL pts. The most notable mutations were found in the ITIM2 of KIR3DL1 and KIR2DL3 (3 subjects) and in the vicinity of the ITIM1 and CK2 phosphorylation sites of KIR2DL3 and KIR3DL2 (5 subjects). The latter mutations were associated with higher CXCL12/CXCR4 expression ratio (~3 fold) and susceptibility to response to tipifarnib. Two complete responses (CR), 2 partial responses and one disease stabilization (80% ORR) were observed in 5 AITL subjects carrying Q386E KIR3DL2. One additional CR was observed in 1 of 4 PTCL NOS pts with Q386E KIR3DL2. Nine of 27 PTCL samples (33%) carried Q386E. An additional 11 samples from tipifarnib treated pts and the overall incidence of KIR-DL mutation in PTCL and other lymphomas are being investigated.

**Conclusions:** The high rate of inhibitory KIR mutation in AITL may contribute to the understanding of the hypervascularity and inflammatory phenotype of these tumors. The association of KIR3DL2 mutation with objective response may provide a robust method for the selection or stratification of AITL and other lymphoma pts who could benefit from tipifarnib therapy.

**Keywords:** angioimmunoblastic T-cell lymphoma (AITL); chemokines; peripheral T-cell lymphomas (PTCL).

**Disclosures:** Gualberto, A: Employment Leadership Position: Kura Oncology; Stock Ownership: Kura Oncology. Scholz, C: Employment Leadership Position: Kura Oncology; Stock Ownership: Kura Oncology.

**Mishra, V:** Employment Leadership Position: Kura Oncology; Stock Ownership: Kura Oncology. Kessler, L: Employment Leadership Position: Kura Oncology; Stock Ownership: Kura Oncology. Rodriguez, M: Research Funding: Kura Oncology. Piris, M: Research Funding: Kura Oncology. Witzig, T: Research Funding: Investigator for KO-TIP-002 (Kura Oncology Sponsored Clinical Study).

## 157 KIR3DL2 IS EXPRESSED IN PERIPHERAL T-CELL LYMPHOMAS AND MAY BE A THERAPEUTIC TARGET

M. Cheminant<fnref n="1" /> | A. Decroos<fnref n="2" /> | J. Bruneau<fnref n="3" /> | S. Carras⁴ | L. Pelletier<fnref n="2" /> | N. Martin<fnref n="2" /> | V. Peri⁵ | F. Guillot⁵ | C. Paturel⁵ | H. Sicard⁵ | C. Bonnafous⁵ | L. Lhermitte⁶ | T. Molina<fnref n="3" /> | V. Asnafi⁶ | L. Genestier⁴ | P. Gaulard<fnref n="7" /> | N. Ortonne<fnref n="7" /> | O. Hermine<fnref n="1" />

**Introduction:** KIR3DL2, a killer immunoglobulin-like receptor normally expressed by a subset of natural killer (NK) cells and a minority of CD4+ and CD8+ T lymphocytes, is aberrantly expressed in cutaneous T-cell lymphomas (CTCL), particularly in Sézary Syndrome (SS)<fnref n="1" />. IPH4102, a monoclonal antibody directed against KIR3DL2, demonstrated *in-vitro* antitumor activity and has shown beneficial clinical activity in a phase 1 dose-escalation plus expansion cohort study in relapsed advanced CTCL patients (NCT02593045)<fnref n="2" />,<fnref n="3" />.

**Methods:** Our cohort included a total of 91 peripheral TCL (PTCL) patients. NK receptors expression was assessed by immunohistochemistry (IHC) on frozen biopsies (n = 49), and by flow-cytometry

<footnote n="1">¹Development, Kura Oncology, Inc., Cambridge, United States;</footnote>

<footnote n="2">²Development, Kura Oncology, Inc., San Diego, United States;</footnote>

<footnote n="3">³Pathology, Fundación Jiménez Díaz, Madrid, Spain; ⁴Hematology, Hematopathology, Mayo Clinic, Rochester, United States</footnote>

<footnote n="1">¹Clinical Hematology, Necker University Hospital, Paris, AP-HP, France;</footnote>

<footnote n="2">²INSERM U955, Université Paris-Est, Créteil, France; ³Pathology Department, Necker University Hospital, Paris, AP-HP, France; ⁴Centre de Recherche en Cancérologie de Lyon (CRCL), INSERM U1052-CNRS UMR5286, Centre Léon Bérard, Université Claude Bernard Lyon I, Lyon, France; ⁵Innate Pharma, Innate Pharma, Marseille, France; ⁶Biological Hematology, Necker University Hospital, Paris, AP-HP, France;</footnote>

<footnote n="7">⁷Pathology department, Groupe Hospitalier Henri Mondor, Créteil, AP-HP, France</footnote>
<figure><img src="image_114.png" /></figure>

<figure><img src="image_115.png" /></figure>

(n = 42) on peripheral blood samples (n = 12) and lymph node/tumor tissue (n = 30). Ex-vivo antibody dependent cell cytotoxicity (ADCC) assays are currently being performed on sorted primary KIR3DL2-positive PTCL cells with IPH4102. Finally, IPH4102 and gemcitabine plus oxaliplatin (GemOx), a combination chemotherapy regimen commonly used in relapsed PTCL, was studied in-vitro.

**Results:** Overall, irrespective of the staining technique, KIR3DL2 expression was evidenced in 41/91 (45%) of PTCL patients. More precisely, KIR3DL2 was expressed on 7/20 (35%) PTCL-not otherwise specified (NOS), 9/25 (36%) angioimmunoblastic TCL (AITL), 8/14 (57%) anaplastic large-cell lymphomas (ALCL), 5/11 (45%) enteropathy-associated TCL (EATL), 5/11 (45%) NK/T-cell lymphomas, 0/2 hepatosplenic TCL and 7/8 (88%) T-cell large granular lymphocyte leukemias (T-LGL). By IHC, within all PTCL categories, > 5% of lymphoid cells were KIR3DL2-positive in 22 out of 49 cases (45%). High expression (> 50% KIR3DL2-positive lymphoid cells) was found in 11 (22%) patients (**figure 1A**). In addition, by flow cytometry, KIR3DL2 was expressed on tumor cells compared to isotype control in 18/42 PTCL (43%). Incubation of T-cell lymphoma cell lines with GemOx enhances baseline KIR3DL2 expression. *In-vitro*, IPH4102 ADCC against KIR3DL2-positive tumor T-cell lines is increased by GemOx (**figure 1B**).

**Conclusion:** KIR3DL2 is expressed in multiple PTCL subtypes including the most frequent like PTCL-NOS, AITL and ALCL, but also the rarer EATL, NK/T-cell lymphomas and T-LGL. IPH4102 and GemOx

combination improves anti-tumor activity against KIR3DL2-positive T-cell line *in-vitro*. The benefit of targeting KIR3DL2 by IPH4102 in combination with GemOx will be further investigated in relapsed PTCL patients in the Tellomak Phase 2 study.

**Keywords:** monoclonal antibodies (MoAb); peripheral T-cell lymphomas (PTCL).

**Disclosures:** Cheminant, M: Research Funding: yes. Bruneau, J: Research Funding: yes. Peri, V: Employment Leadership Position: yes. Guillot, F: Employment Leadership Position: yes. Paturel, C: Employment Leadership Position: yes. Sicard, H: Employment Leadership Position: yes. Bonnafous, C: Employment Leadership Position: yes; Stock Ownership: yes. Hermine, O: Research Funding: yes.

158
A PTCL GENE SIGNATURE CAPTURING STROMAL AND NEOPLASTIC DATA STRATIFIES PTCL/NOS AND AITL INTO DIFFERENT GROUPS WITH VARIABLE SURVIVAL PROBABILITY

M. Rodriguez¹ | R. Alonso¹ | S. Rodriguez-Pinilla¹ |

L. Cereceda¹ | T. Villaescusa² | R. Cordoba² |

M. Sánchez-Beato³ | I. Fernandez-Miranda³ |
C. Bárcena⁴ | J. García⁵ | M. Mollejo⁶ |

M. Garcia-Cosio⁷ | P. Martin-Acosta⁸ | F. Climent⁹ |

D. Caballero¹⁰ | L. Kessler¹¹ | C. Scholz¹² |

A. Gualberto¹² | R. Mondéjar¹³ | M. Piris¹

¹Pathology, Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Instituto de Investigación Fundación Jiménez Díaz, Madrid, Spain; ²Haematology, Instituto de Investigación Fundación Jiménez Díaz, Madrid, Spain; ³Medical Oncology, Instituto Investigación Sanitaria Puerta de Hierro-Segovia de Arana, Madrid, Spain; ⁴Pathology, Hospital Universitario 12 de Octubre, Madrid, Spain; ⁵Pathology, Hospital MD Anderson Cancer Center, Madrid, Spain; ⁶Pathology, Hospital Virgen de la Salud, Toledo, Spain; ⁷Pathology, Instituto de Investigación Hospital Ramón y Cajal, Madrid, Spain; ⁸Pathology, Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Instituto de Investigación Sanitaria Puerta de Hierro-Segovia de Arana, Madrid, Spain; ⁹Pathology, Hospital Universitario de Bellvitge, Barcelona, Spain; ¹⁰Haematology, Hospital Clínico Universitario de Salamanca, Salamanca, Spain; ¹¹Kura Oncology, San Diego, CA, United States; ¹²Kura Oncology, Cambridge, MA, United States; ¹³Haematology, Hospital Universitario Virgen del Rocío, Sevilla, Spain

**Introduction:** Peripheral T-cell lymphoma, NOS (PTCL-NOS) and angioimmunoblastic T-cell lymphoma (AITL) are aggressive lymphoma types with a low survival probability, where prognostic models are mainly based on clinical data at diagnosis or proliferation rate of the neoplastic cells.

We hypothesized that gene profiles from diagnostic samples could be used to define prognostic risk groups to identify patients with different survival probabilities.

**Methods:** PTCL-NOS and AITL (n. 96 with high quality RNA) samples treated with chemotherapy were profiled for a 216 genes custom T-cell lymphoma CodeSet, using the NanoString platform. The analysis was designed for including genes expressed by the different components of the stroma and neoplastic cells, together with genes known to be therapeutic targets.

Genes associated with overall survival (OS) were identified using Cox regression, followed by generation of risk scores and development of a assay to stratify patients into risk groups associated with OS. Co-regulated genes were investigated for identifying the best prognostic marker.

**Results:** Regression and clustering analysis defined a 10-genes PTCL Gene Signature and two risk groups with different OS [hazard ratio (HR) 5.77; 95% CI 2.23-14.95; p = 0.002]. The median OS of high- and low-risk groups were 47 [95% confidence interval (CI) of 13.80 and 80.20 months] and 17 months [95% CI: 9.93 months and 24.07], respectively. These risk groups were independent of the CPI.

The PTCL gene signature includes genes expressed by both neoplastic and stromal cells (endothelium, macrophages, immunoregulatory cells, cytokines, oncogenes) and was valid for both PTCL-NOS and AITL.

**Conclusions:** These results suggest that gene expression-based risk groups, capturing data from both the stroma and the neoplastic cells, can independently predict survival in PTCL/NOS and AITL.

This signature may help to stratify these patients for different therapeutic strategies in future clinical trials.

**Keywords:** gene expression profile (GEP); peripheral T-cell lymphomas (PTCL).

159
MULTICENTRIC MFI30 STUDY:
STANDARDIZATION OF CD30 EXPRESSION
BY FLOW CYTOMETRY IN NON-HODGKIN
LYMPHOMA

L. Baseggio¹ | A. Debliquis² | M. Jacob³ |

S. Bouyer⁴ | H. Bennani⁵ | N. Chapuis⁶ |

F. Garnache Ottou⁷ | F. Genevieve⁸ | J. Guy⁹ |

V. Harrivel¹⁰ | R. Letestu¹¹ | C. Mayeur-Rousse¹² |

B. Drenou²

¹Laboratoire d'Hématologie, Hospice Civils de Lyon/Groupement Hospitalier SUD, Pierre Benite, France; ²Laboratoire Hématologie, Groupe Hospitalier de la Région Mulhouse Sud Alsace (GHRMSA), Mulhouse, France; ³Laboratoire Immunologie, CHU Grenoble, Grenoble, France; ⁴Laboratoire de Biologie, CHU Poitiers, Poitiers, France; ⁵Laboratoire de Biologie, Hôpital Foch, Suresnes, France; ⁶Laboratoire Hématologie, APHP-Cochin, Paris, France; ⁷Hematologie, EFS BFC, Besançon, France; ⁸Laboratoire Hématologie/Institut de Biologie/Cytométrie en Flux, CH Angers, Angers, France; ⁹Laboratoire Hématologie/Plateforme de Cytométrie, CHU-Dijon, Dijon, France; ¹⁰Centre de Biologie Humaine, CHU Amiens, Amiens, France; ¹¹Laboratoire Hématologie, APHP-Avicenne, Bobigny, France; ¹²Laboratoire Hématologie, CHU de Strasbourg, Strasbourg, France

**Introduction:** The Brentuximab vedotin (BV), an anti-CD30 monoclonal antibody (Ab) conjugated to chemotherapy, has shown its efficacy in Hodgkin lymphoma (HL) and anaplastic large cell lymphoma (ALCL) that typically expressed the CD30. However, the response to BV is difficult to correlate to CD30 expression analyzed by immunohistochemistry (IHC) which only allows the count of high positive cells. The objective of this multicentric study is to standardize and evaluate CD30 expression by flow cytometry (FCM) in malignant T and B-cell proliferation.

**Material and methods:** Among 18 centers participating to the first step of standardization, 12 included cases (n = 155): 5 ALCL, 70 B-NHL including 64 DLBCL, 80 malignant T-cell proliferations (24 Sezary, 26 PTCL-NOS, 14 T-PLL, 8 AITL, 2 EATL, 6 T / NK-LGL) from various samples (74 bloods, 43 lymph node suspensions, 10 bone marrows, 28 others) (www.mfi30.fr). BD Biosciences (BD, n = 9) or Beckman Coulter (BC, n = 9) cytometers are used with the Euroflow strategy. Abs recognizing different CD30 epitopes are tested: BerH83 (BD), HRS4 (BC) and AC10 (Ancell) which recognizes the same epitope as
<figure><img src="image_116.png" /></figure>

BV. The mean fluorescence intensity (MFI) of CD30 is normalized in % compared to CD4 (nMFI30). Abs BC and BD are tested if only nMFI30> 1% with Ab Ancell. In 85 cases IHC has been also realized with the clone BerH2 (Dako).

**Results:** FCM results has allowed to define 4 groups (Fig: a high positive group (n = 11) with nMFI30> 5% with the 3 Abs tested; a dim positive group (n = 16) with nMFI30 between 1 and 5% with the 3 Abs tested; a discordant group (n = 19) with nMFI30> 1% with Ab Ancell and <1% with another Ab; a negative group (n = 109) with nMFI30 <1% with Ab Ancell. When tested, IHC is positive in all cases of high positive group (10), in 4 out of 7 in the dim positive group, 10 out of 16 in the discordant group, and in 7 out of 52 in the negative group (2 AITL, 1 PTCL-NOS and 4 DLBCL). This last discordance could be explained by CD30 expression of non-tumoral cells present in microenvironment or by intracytoplasmic staining. 10/38 DLBCL are positive by IHC (26%) and 21/64 (33%) are in positive or discordant groups by FCM. 6/13 Sezary are positive by IHC (46%) and 7/24 (29%) are in positive or discordant groups by FCM. All ALCL are positive by both techniques. All T-PLLs, DLBCL-CNS and LGL are negative.

**Conclusion** Multicenter standardization of CD30 is achievable by FCM, using in particular the AC10 and making it therefore a powerful tool for clinical trials to extend the treatment of BV to various NHL.

**Keywords:** brentuximab vedotin; flow cytometry; non-Hodgkin lymphoma (NHL).

**Disclosures:** BASEGGIO, L: Consultant Advisory Role: consultant role; Honoraria: yes. Debliquis, A: Consultant Advisory Role: consultant; Honoraria: yes. Jacob, M: Consultant Advisory Role: consultant; Honoraria: yes. Drenou, B: Consultant Advisory Role: consultant; Honoraria: yes.

CLL

160
SURVIVAL CONTINUES TO INCREASE IN
CHRONIC LYMPHOCYTIC LEUKEMIA: A
POPULATION-BASED ANALYSIS AMONG
20,324 PATIENTS DIAGNOSED IN THE
NETHERLANDS BETWEEN 1989 AND 2015

L. van der Straten<fnref n="1" /> | M. Levin<fnref n="1" /> | O. Visser<fnref n="2" /> |
E.F. Posthuma³ | J.K. Doorduijn⁴ | A.P. Kater⁵ |
A.G. Dinmohamed⁶

**Introduction:** The treatment landscape in chronic lymphocytic leukemia (CLL) rapidly evolved since the last decade with improvements in supportive care and the advent of anti-CD20 agents, kinase inhibitors, and anti-apoptotic agents. At present, it is largely unknown how these advances impacted survival of patients with CLL at the population level. The aim of this nationwide, population-study was to assess trends in long-term excess mortality (EM) among patients with CLL diagnosed during a 27-year period in the Netherlands.

<footnote n="1">¹Internal Medicine, Albert Schweitzer hospital, Dordrecht, Netherlands;</footnote>

<footnote n="2">²Registration, Netherlands Comprehensive Cancer Organisation (IKNL), Utrecht, Netherlands; ³Internal Medicine, Reinier de Graaf Gasthuis, Delft, Netherlands; ⁴Hematology, Erasmus MC Cancer Institute,</footnote>

<footnote>Rotterdam, Netherlands; ⁵Hematology, Amsterdam University Medical Center, Academic Medical Center, Cancer Center Amsterdam, Amsterdam, Netherlands; ⁶Research, Netherlands Comprehensive Cancer Organisation (IKNL), Utrecht, Netherlands</footnote>
<figure><img src="image_117.png" /><figcaption>Table 1 EMR during the first 10 years after CLL diagnosis</figcaption></figure>

<table><thead><tr><th>Covariate</th><th>EMR<sup>1</sup></th><th>95% CI</th><th>P<sup>2</sup></th></tr></thead><tbody><tr><td>Period of diagnosis</td><td></td><td></td><td></td></tr><tr><td>1989-1995</td><td>2.04</td><td>1.86 - 2.23</td><td>&lt;0.001</td></tr><tr><td>1996-2002</td><td>1.45</td><td>1.32 - 1.58</td><td>&lt;0.001</td></tr><tr><td>2003-2008</td><td>1</td><td>(reference)</td><td></td></tr><tr><td>2009-2016</td><td>0.65</td><td>0.58 - 0.74</td><td>&lt;0.001</td></tr><tr><td>Sex</td><td></td><td></td><td></td></tr><tr><td>Male</td><td>1</td><td>(reference)</td><td></td></tr><tr><td>Female</td><td>0.66</td><td>0.61 - 0.71</td><td>&lt;0.001</td></tr><tr><td>Age at diagnosis, years</td><td></td><td></td><td></td></tr><tr><td>18-59</td><td>1</td><td>(reference)</td><td></td></tr><tr><td>60-69</td><td>1.43</td><td>1.30 - 1.58</td><td>&lt;0.001</td></tr><tr><td>70-79</td><td>2.08</td><td>1.89 - 2.29</td><td>&lt;0.001</td></tr><tr><td>≥80</td><td>3.90</td><td>3.47 - 4.38</td><td>&lt;0.001</td></tr><tr><td>Previous malignancy</td><td></td><td></td><td></td></tr><tr><td>No</td><td>1</td><td>(reference)</td><td></td></tr><tr><td>Yes</td><td>1.80</td><td>1.64 - 1.96</td><td>&lt;0.001</td></tr></tbody><tfoot><tr><td colspan="4">Abbreviations: EMR, excess mortality ratio.<br><sup>2</sup>All covariates are simultaneously adjusted.<br><sup>3</sup>P-values are compared with the reference category.</td></tr></tfoot></table>

**Methods:** We selected all 20,324 patients with CLL diagnosed between 1989-2016 (median age 69 years; range 21-101 years; 61% males; 11% with a prior malignancy) from the Netherlands Cancer Registry, with follow-up for survival through January, 2018. Patients were categorized into four periods (1989-1995, 1996-2002, 2003-2008, and 2009-2016) and four age groups (18-59, 60-69, 70-79, and ≥80 years). Age-standardized incidence rates (ASRs) were calculated per 100,000 person-years and standardized according to the European standard population. Relative survival (RS) was calculated as a measure of disease-specific survival. Multivariable evaluation of RS was performed using Poisson regression with adjustment for period of diagnosis, sex, age at diagnosis, and a prior malignancy before CLL diagnosis.

**Results:** The annual ASR of CLL initially increased gradually since 1989; however, the overall incidence pattern subsequently stabilized at around 4.0 to 4.5 as from 2003. The overall ASR was consistently higher among males than females throughout the entire study period (5.0 vs. 2.6 in 1989-2015). Patients across the four age groups experienced continued EM, as compared to the general population during all periods studies. Nevertheless, RS improved with each period for all 4 age groups (Figure 1). More specifically, 5-year RS was 80%, 71%, 64%, and 52% in 1989-1995 for the 4 age groups, as compared with 94%, 90%, 84%, and 75% in 2009-2015 (P<0.001 for all comparisons). The multivariable analysis confirmed an improvement of survival over time, with an EM ratio (EMR) of 2.04 (P<0.001) in 1989-1995, 1.45 (P<0.001) in 1996-2002, and 0.65 (P<0.001) in 2009-2015, as compared with 2003-2008. Furthermore, females had lower EM, as compared to males (EMR, 0.66; P<0.001), whereas patients with a prior malignancy had higher EM, as compared with patients without a prior malignancy (EMR, 1.80; P<0.001) (Table 1). Subgroup analyses confirmed the consistency of the abovementioned associations across the four age groups, with the exception that females and males age ≥80 had comparable EM (EMR, 0.99; P = 0.906).

**Conclusion:** In this large, nationwide, population-based study, 5- and 10-year RS improved over time among patients with CLL across all age groups. Advances in supportive care, ameliorated management, and the advent of novel agents might have accounted for the

improvement. As kinase inhibitors and anti-apoptotic agents have been introduced recently for routine use, EM will hopefully improve even more in the next decade.

**Keywords:** chronic lymphocytic leukemia (CLL).

161
PROTEOMICS MARKERS PROGNOSTIC FOR OUTCOME OF CHRONIC LYMPHOCYTIC LEUKEMIA PATIENTS UNDER TREATMENT: RESULTS FROM THE HOVON-109 STUDY

L. van der Straten<fnref n="1" /> | F. Hosnijeh<fnref n="2" /> | L. van der Straten<fnref n="1" /> |
A.P. Kater³ | M.H. van Oers³ | W.F. Posthuma⁴ |
M.E. Chamuleau⁵ | M. Nijland⁶ | M. Hoogendoorn⁷ |
F. De Croon⁸ | S. Wittebol⁹ | J. Kerst¹⁰ |
E.W. Marijt¹¹ | R.A. Raymakers¹² | H.R. Koene¹³ |
J.A. Dobber¹⁴ | S.H. Tonino³ | S.S. Kersting¹⁵ |
A.W. Langerak<fnref n="2" /> | M. Levin<fnref n="1" />

<footnote n="1">¹Internal Medicine, Albert Schweitzer Hospital, Dordrecht, Netherlands;</footnote>

<footnote n="2">²Immunology, Laboratory Medical Immunology, Erasmus MC, University Medical Center, Rotterdam, Netherlands; ³Hematology and Lymphoma and Myeloma Center Amsterdam, Academic Medical Center, Amsterdam, Netherlands; ⁴Internal Medicine, Reinier de Graaf Hospital, Delft, Netherlands; ⁵VU University Medical Center, Hematology, Amsterdam, Netherlands; ⁶Hematology, University Medical Center Groningen, Groningen, Netherlands; ⁷Internal Medicine, Medical Center Leeuwarden, Leeuwarden, Netherlands; ⁸Internal Medicine, Ikazia Hospital, Rotterdam, Netherlands; ⁹Internal Medicine, Gelderland Valley Hospital, Ede, Netherlands; ¹⁰Medical Oncology, Antoni van Leeuwenhoek Hospital, Amsterdam, Netherlands; ¹¹Hematology, Leiden University Medical Center, Leiden, Netherlands; ¹²Hematology, University Medical Center Utrecht, Utrecht, Netherlands; ¹³Hematology, St. Antonius Hospital, Nieuwegein, Netherlands; ¹⁴Laboratory Special Hematology, Academic Medical Center, Amsterdam, Netherlands; ¹⁵Hematology, HAGA hospital, the Hague, Netherlands</footnote>
<figure><img src="image_118.png" /></figure>

1: IGHV Mutated & sCD23 ≤ median

2: IGHV Mutated & sCD23 > median

3: IGHV Unmutated & sCD23 ≤ median

4: IGHV Unmutated & sCD23 > median

<table><caption>Cox regression models for combination of the proteomics markers related to EFS</caption><thead><tr><th rowspan="2"></th><th colspan="2">M0</th><th colspan="2">M1</th><th colspan="2">M2 (stepwise)</th></tr><tr><th>B (SE)</th><th>P</th><th>B (SE)</th><th>P</th><th>B (SE)</th><th>P</th></tr></thead><tbody><tr><td>Female</td><td>-0.93 (0.46)</td><td><strong>0.04</strong></td><td>-0.76 (0.50)</td><td>0.12</td><td>-1.58 (0.60)</td><td><strong>0.008</strong></td></tr><tr><td>Un-mutated IGHV</td><td>1.45 (0.47)</td><td><strong>0.002</strong></td><td>-9.89 (5.5)</td><td>0.07</td><td>1.36 (0.57)</td><td><strong>0.016</strong></td></tr><tr><td>sCD23</td><td></td><td></td><td>-1.49 (0.83)</td><td>0.07</td><td>-1.31 (0.39)</td><td><strong>0.0009</strong></td></tr><tr><td>sCD23* IGHV</td><td></td><td></td><td>1.01 (0.49)</td><td><strong>0.04</strong></td><td>NS</td><td></td></tr><tr><td>SPINT1</td><td></td><td></td><td></td><td></td><td>1.28 (0.59)</td><td><strong>0.031</strong></td></tr><tr><td>LY9</td><td></td><td></td><td></td><td></td><td>1.95 (0.75)</td><td><strong>0.009</strong></td></tr><tr><td>IFNL1</td><td></td><td></td><td></td><td></td><td>NS</td><td></td></tr><tr><td>ITM2A</td><td></td><td></td><td></td><td></td><td>NS</td><td></td></tr><tr><td>CLEC7A</td><td></td><td></td><td></td><td></td><td>-0.83 (0.24)</td><td><strong>0.0007</strong></td></tr><tr><td>TCL1A</td><td></td><td></td><td></td><td></td><td>NS</td><td></td></tr><tr><td>R square (corrected)</td><td>0.28 (0.24)</td><td></td><td>0.36 (0.27)</td><td></td><td>0.60 (0.48)</td><td></td></tr><tr><td>AUC (corrected)</td><td>0.40 (0.38)</td><td></td><td>0.52 (0.46)</td><td></td><td>0.68 (0.61)</td><td></td></tr></tbody></table>

R square and AUC corrected for overfitting by 100 times bootstrapping; non-significant (NS)

<figure><img src="image_119.png" /></figure>

**Introduction:** Chronic lymphocytic leukemia (CLL) follows a highly variable clinical course. In recent years, several molecular and cellular markers have been explored and correlated with disease aggressiveness in order to enable risk group stratification. However, since many CLL cases show discordant prognostic factors, the identification of new parameters able to relate disease stage and clinical outcome is important to further improve treatment efficacy. Therefore, the aim of our study was to examine the prognostic ability of a) known proteomics markers measured pre-treatment and b) to search for new proteomics markers that might be related to treatment response.

**Methods:** Samples of CLL patients treated with chlorambucil, rituximab and lenalidomide within the HOVON-109 trials were collected. Fifty-one of 63 patients had an available sample at baseline and were included in our study. Serum samples were analyzed for 360 proteomics markers using a multiplex proximity extension assay (Olink Bioscience, Uppsala, Sweden). Kaplan-Meier curves and Cox proportional hazards models were used for testing independent and additive effects of the markers for event-free survival (EFS; time from registration to induction failure, progression or death from any cause, whichever comes first).

**Results:** Fifty-one patients were included (59% males; mean age 71 years). Median EFS was 23 months (26 events). Female and IGHV mutated patients showed longer EFS, as compared to male and unmutated patients. No significant survival effects were seen for β2-microglobulin levels, Rai stage, or well-defined chromosomal aberrations. Among B-cell activation markers, the sCD23 level was associated with EFS in univariate (β = 0.45, p = 0.04) and adjusted models (β = -1.49, p = 0.07). Patients with high (i.e. above median) sCD23

levels had a shorter EFS, as compared to those with low levels (Fig 1). There was a significant interaction between sCD23 and IGHV mutational status (β = 1.01, P = 0.04), as unmutated IGHV patients with high sCD23 levels had the shortest EFS (Fig 1). Low levels (i.e. equal to or below median) of SPINT1 and LY9 levels were correlated with a significantly longer survival. Added prognostic value of the potential proteomics markers compared with a basic model including gender and IGHV status was evaluated, showing a significant independent effect on EFS for especially sCD23, SPINT1, and LY9 (Fig 1). Several other evaluated proteomics markers were significantly associated with EFS in univariate and adjusted models, albeit, none remained significant after multiple testing correction.

**Conclusion:** Our study suggests a possible prognostic role for sCD23 (probably released from activated B-cells), LY9 (probably from CD4+T helper cells), and SPINT1 (a potent inhibitor specific for HGF activator) in CLL patients in this clinical trial. Further studies are required to validate these results.

**Keywords:** chemokines; chronic lymphocytic leukemia (CLL); cytokines.

162
Acalabrutinib With Obinutuzumab in Treatment-Naive and Relapsed/Refractory Chronic Lymphocytic Leukemia: 3-Year Follow-Up

J. Woyach¹ | K.A. Rogers¹ | S. Bhat¹ | J. Blachly¹ |

M. Jianfar¹ | A. Hamdy² | M.M. Frigault³ |
R. Izumi² | V. Munugalavadla³ | C.S. Quah⁴ |

M.H. Wang⁴ | J.C. Byrd²

¹Internal Medicine, The Ohio State University Comprehensive Cancer Center, Columbus, OH, United States; ²Early Research and Development, Acerta Pharma, South San Francisco, CA, United States;

³Translational Science, Acerta Pharma, South San Francisco, CA, United States; ⁴Clinical Development, Acerta Pharma, South San Francisco, CA, United States

**Background:** Acalabrutinib is a highly selective, potent, covalent Bruton tyrosine kinase inhibitor. This Phase 1b/2 trial evaluated acalabrutinib with the CD20 antibody obinutuzumab in patients with treatment-naïve or relapsed/refractory chronic lymphocytic leukemia (CLL).

**Methods:** Patients with treatment-naïve or relapsed/refractory (≥1 prior therapy) CLL were eligible. In 28-day cycles, acalabrutinib was given orally at 100 mg twice daily or 200 mg once daily (n = 15; all switched to 100 mg twice daily) until progressive disease; obinutuzumab was given in standard fashion for 6 cycles starting with Cycle 2. The primary endpoints were overall response rate and safety. Minimal residual disease (MRD) was assessed using flow cytometry (sensitivity 10⁻⁴).

**Results:** Nineteen treatment-naïve and 26 relapsed/refractory patients were treated. The median age of all patients was 61 years (range, 42 to 76). Patient characteristics, disposition, efficacy, and MRD data are in the **Table**. Common adverse events (any grade) were upper respiratory tract infection (71%), increased weight (71%), maculopapular rash (67%), cough (64%), diarrhea (62%), headache (56%), nausea (53%), arthralgia (51%), and dizziness (47%). Common Grade 3/4 adverse events were decreased neutrophil count (24%), syncope (11%), decreased platelet count, increased weight, and cellulitis (9% each). There were 2 (4%) Grade 3 bleeding events (hematuria, muscle hemorrhage) and 1 (2%) Grade 3 atrial fibrillation event.

**Conclusions:** Acalabrutinib plus obinutuzumab was well tolerated and yielded high response rates that were durable and deepened over time in treatment-naïve and relapsed/refractory patients with CLL.

**Keywords:** BTK inhibitors; CD20; minimal residual disease (MRD).

**Disclosures:** Woyach, J: Consultant Advisory Role: Janssen, Pharmacyclics; Research Funding: Janssen, Pharmacyclics, Karyopharm, Morphosys, Abbvie, Loxo. Rogers, K: Consultant Advisory Role: Acerta Pharma; Research Funding: Genentech and AbbVie. Bhat, S: Other Remuneration: Janssen and Pharmacyclics. Blachly, J: Consultant Advisory Role: Abbvie, AstraZeneca, Kite Pharma; Research Funding: Min-gSight Pharmaceuticals Pty Ltd; Other Remuneration: Ohio State University. Hamdy, A: Employment Leadership Position: Acerta Pharma; Stock Ownership: Acerta Pharma; Other Remuneration: Acerta Pharma. Frigault, M: Employment Leadership Position: Acerta Pharma/AstraZeneca; Stock Ownership: Acerta Pharma/AstraZeneca. Izumi, R: Employment Leadership Position: Acerta Pharma/AstraZeneca; Stock Ownership: Acerta/Astra Zeneca. Munugalavadla,

<table><caption>TABLE 1</caption><thead><tr><th></th><th>Treatment naive (n = 19)</th><th>Relapsed/refractory (n = 26)</th></tr></thead><tbody><tr><td>Percent of patients</td><td></td><td></td></tr><tr><td>Lymph nodes ≥5 cm</td><td>53</td><td>50</td></tr><tr><td>del17p</td><td>22<sup>a</sup></td><td>19</td></tr><tr><td>del11q</td><td>28<sup>a</sup></td><td>35</td></tr><tr><td>Complex karyotype</td><td>42</td><td>56</td></tr><tr><td>IGHV unmutated</td><td>53<sup>b</sup></td><td>65</td></tr><tr><td>Follow-up, median (range), mo</td><td>36 (1-42)</td><td>39 (20-46)</td></tr><tr><td>Discontinued, n (%)</td><td>2 (11)</td><td>7 (27)</td></tr><tr><td>Adverse event</td><td>1 (5)</td><td>4 (15)</td></tr><tr><td>Richter transformation</td><td>1 (5)</td><td>2 (8)</td></tr><tr><td>Death</td><td>0</td><td>1 (4)<sup>c</sup></td></tr><tr><td>Overall response rate (≥ PR), %</td><td>95</td><td>92</td></tr><tr><td>95% CI</td><td>74, 100</td><td>75, 99</td></tr><tr><td>CR, n (%)</td><td>6 (32)</td><td>2 (8)</td></tr><tr><td>PR, n (%)</td><td>12 (63)</td><td>22 (85)</td></tr><tr><td>Median time to CR (range), mo</td><td>18 (6-32)</td><td>13 (10-16)</td></tr><tr><td>Median time to ≥ PR (range), mo</td><td>3 (3-3)</td><td>3 (3-21)</td></tr><tr><td>Median DOR</td><td>NR</td><td>NR</td></tr><tr><td>33-mo DOR rate, % (95% CI)</td><td>94 (67, 99)</td><td>91 (68, 98)<sup>d</sup></td></tr><tr><td>Median PFS</td><td>NR</td><td>NR</td></tr><tr><td>36-mo PFS rate, % (95% CI)</td><td>94 (67, 99)</td><td>73 (34, 91)<sup>e</sup></td></tr><tr><td>MRD- in bone marrow Cycle 12 Day 1, n (%)</td><td>5 (26)<sup>f</sup></td><td>4 (15)</td></tr></tbody></table>

Abbreviations: CR, complete response; DOR, duration of response; MRD, minimal residual disease; NR, not reached; PFS, progression-free survival; PR, partial response.

a¹ or b² 2 patients missing data.

cDue to progressive disease.

d³⁹-mo rate.

e⁴²-mo rate.

fIncludes 3/6 patients in CR.

V: Employment Leadership Position: Acerta Pharma, Gilead Sciences.

Quah, C: Employment Leadership Position: Acerta Pharma. Wang, M:

Employment Leadership Position: Acerta Pharma. Byrd, J: Research

Funding: Acerta Pharma, Genentech, Janssen, Pharmacyclics.
R. Greil¹ | A. Tedeschi² | C. Moreno³ | B. Anz⁴ |
L. Larratt⁵ | M. Simkovic⁶ | D. Gill⁷ | J.G. Gribben⁸ |
I.W. Flinn⁹ | Z. Wang¹⁰ | L.W. Cheung¹⁰ |
A.N. Nguyen¹⁰ | C. Zhou¹¹ | L. Styles¹² | F. Demirkan¹³

¹Department of Immunological and Molecular Cancer Research, Paracelsus Medical University Salzburg, Salzburg Cancer Research Institute, Cancer Cluster Salzburg, Salzburg, Austria; ²Department of Hematology, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy; ³Department of Hematology, Hospital de la Santa Creu i Sant Pau, Autonomous University of Barcelona, Barcelona, Spain; ⁴Department of Medical Oncology, Tennessee Oncology, Chattanooga, United States; ⁵Department of Clinical Hematology, University of Alberta Hospital, Edmonton, Canada; ⁶Department of Internal Medicine - Hematology, University Hospital and Medical School Hradec Kralove, Hradec Kralove, Czech Republic; ⁷Department of Clinical Hematology, Princess Alexandra Hospital, Brisbane, Australia; ⁸Centre for Haematology-Oncology, Queen Mary, University of London, Barts Cancer Institute, London, United Kingdom; ⁹Center for Blood Cancers, Medical Oncology, Sarah Cannon Research Institute/Tennessee Oncology, Nashville, United States; ¹⁰Translational Medicine, Pharmacyclics LLC, an AbbVie Company, Sunnyvale, United States; ¹¹Biostatistics, Pharmacyclics LLC, an AbbVie Company, Sunnyvale, United States; ¹²Clinical Science, Pharmacyclics LLC, an AbbVie Company, Sunnyvale, United States; ¹³Department of Hematology, Dokuz Eylül University, Izmir, Turkey

**Introduction:** Infusion-related reactions (IRRs) are potentially serious complications resulting from release of inflammatory cytokines in response to administration of certain drugs, including obinutuzumab (G), an anti-CD20 antibody (Freeman, Blood 2015). In the phase 3 iLLUMINATE study of first-line ibrutinib-G (ibr-G) vs chlorambucil-G (clb-G) in patients (pts) with chronic lymphocytic leukemia (CLL), IRRs were decreased with ibr-G vs clb-G (any grade: 25% vs 58%; grade ≥3 or serious: 3% vs 9%) (Moreno, Lancet Oncol 2019). As IRR results from the release of inflammatory cytokines, we prospectively analyzed cytokines thought to be associated with IRRs in pts from iLLUMINATE to evaluate the impact of ibr on secretion of cytokines following G infusion.

**Methods:** Pts with previously untreated CLL/small lymphocytic lymphoma were randomized to ibr-G or clb-G. Ibr or clb was given approximately 30-120 min before the first G infusion. Plasma samples were collected at 4 timepoints (before ibr/clb, immediately before G infusion, and 2h and 4h post-G infusion) on day 1. Cytokines evaluated were IFNγ, IL6, IL8, IL10, IL18, MCP1, MIP1α, MIP1β, and TNFα. Changes from baseline (immediately before G infusion) to post-G infusion peak cytokine levels were compared between arms and between pts with vs without IRRs using Wilcoxon rank sum test. A 2-sided P value of <0.05 was considered significant with no adjustments for multiplicity.

**Results:** Of 229 randomized pts, 95 pts on ibr-G (15 with IRR; 80 without IRR) and 88 pts on clb-G (45 with IRR; 43 without IRR) had cytokine data and were included in the analysis population. Baseline

characteristics were similar between arms, except for lower platelets in ibr-G pts and higher baseline MCP1 levels in clb-G pts. As expected, all cytokine levels increased after infusion of G. Analysis of cytokine levels by treatment arm (ibr-G vs clb-G), irrespective of IRR occurrence, revealed that the median increase in cytokines was lower in ibr-G vs clb-G pts for all cytokines (P<0.01) except MIP1β (Figure). When analyzing pts with and without IRR, the median increase in post-G peak from baseline was greater in pts with vs without IRR for all cytokines (P<0.001) except MIP1β. Analysis of cytokine levels in pts with and without IRR within each treatment arm showed that IL6 and IL8 elevations were associated with IRRs in both treatment arms. In ibr-G arm, pts with IRR had increases in post-G levels of IL6, IL8, IL18, MCP1, MIP1α, and TNFα (P<0.04); in clb-G arm, pts with IRR had increases in IFNγ, IL6, IL8, and IL10 (P<0.03). Among the pts with IRR, ibr-G pts had lower post-G increases in IL6, IL8, IL10, and MCP1 levels (P<0.04) than clb-G pts.

**Conclusions:** These data demonstrate that ibr suppresses G-induced increases in multiple cytokines related to IRRs and suggest that the reduction in IRR events in ibr-treated pts is the result of a reduction in the release of inflammatory cytokines.

**Keywords:** cytokines; ibrutinib; obinutuzumab.

**Disclosures:** Greil, R: Employment Leadership Position: Celgene, Roche, Merck, AstraZeneca, Novartis, Amgen, BMS, MSD, Takeda, Sandoz; Consultant Advisory Role: Celgene, Novartis, Roche, BMS, AbbVie, AstraZeneca, Janssen, Takeda; Research Funding: Celgene, Roche, Merck, AstraZeneca, Novartis, Amgen, BMS, MSD, Takeda, Sandoz; Other Remuneration: Travel, Accomodations, Expenses: Roche, Amgen, Janssen, AstraZeneca. Tedeschi, A: Consultant Advisory Role: Janssen spa, Gilead, AbbVie, SUNESIS; Other Remuneration: Speaker's Bureau: Janssen. Moreno, C: Consultant Advisory Role: Janssen, Pharmacyclics, AbbVie. Larratt, L: Consultant Advisory Role: AbbVie, Janssen. Simkovic, M: Consultant Advisory Role: AbbVie, Roche, Gilead; Honoraria: AbbVie, Janssen-Cilag, Roche, Gilead; Other Remuneration: Speaker's Bureau: AbbVie, Roche, Janssen-Cilag, Gilead; Travel, Accomodations, Expenses: Roche, Janssen-Cilag, Gilead. Gill, D: Consultant Advisory Role: Janssen Cilag; Honoraria: Janssen-Cilag. Gribben, J: Consultant Advisory Role: Pharmacyclics, Janssen; Honoraria: Pharmacyclics LLC, an AbbVie Company, Janssen; Research Funding: Janssen. Flinn, I: Research Funding: Agios, ArQule, Beigene, Calithera, Celgene, Constellation, Curis, Forma, Forty Seven, Genentech, Gilead, Incyte, infinity, Janssen, KITE, Merck, Novartis, Pfizer, Pharmacyclics, Portola, Seattle genetics, Takeda, TG Therapeutics, Trillium, Verastem. Wang, Z: Employment Leadership Position: Pharmacyclics LLC, an AbbVie Company; Stock Ownership: AbbVie, Anaptysbio. Cheung, L: Employment Leadership Position: Pharmacyclics LLC, an AbbVie Company; Stock Ownership: AbbVie & Eli Lilly and Company; Other Remuneration: Patents, Royalties: Pharmacyclics LLC, an AbbVie Company. Nguyen, A: Employment Leadership Position: Pharmacyclics, an AbbVie Company; Stock Ownership: AbbVie; Other Remuneration: Travel, Accomodations, Expenses: AbbVie. Zhou, C: Employment Leadership Position: Pharmacyclics LLC, an AbbVie Company; Stock Ownership: AbbVie. Styles, L: Employment Leadership Position: Pharmacyclics LLC, an AbbVie Company; Stock Ownership: AbbVie. Demirkan, F:
<figure><img src="image_120.png" /><figcaption>Figure. Median change in cytokine levels from baseline to post-G peak by treatment arm.</figcaption></figure>

Consultant Advisory Role: Amgen, Abbvie; Research Funding: Janssen, Abbvie; Other Remuneration: Travel, Accomodations, or Other Expenses: Abbvie, Pfizer, Janssen, Amgen.

164
HYPERTENSION (HTN) IN PATIENTS (PTS) TREATED WITH IBRUTINIB (IBR) FOR CHRONIC LYMPHOCYTIC LEUKEMIA (CLL)

M. Sarraf Yazdy¹ | L. Roeker² | L. Gashonia³ |
J. Goodfriend² | M. Narkhede¹ | J. Rhodes⁴ |
K. Kennard⁴ | H. Morse² | C. Dorsey² |
K. Battiato² | I. Deonarine² | J. Carver³ |
S.J. Schuster⁴ | B.D. Cheson¹ | A. Mato²

¹Hematology Oncology, Georgetown University Hospital, Lombardi
Comprehensive Cancer Center, Washington, United States; ²Hematology
Oncology, Memorial Sloan Kettering Cancer Center, New York, United
States; ³Hematology Oncology, University of Pennsylvania, Philadelphia,
United States; ⁴Hematology Oncology, Abramson Cancer Center,
University of Pennsylvania, Philadelphia, United States

**Introduction:** HTN is the most common grade ≥ 3 Ibr-associated adverse event (AE) in trials (26%) (O'Brien, Blood 2015). Meta-analysis of trials suggests a 2.8-fold increased risk of HTN for pts treated with Ibr (Caldeira, PLOS ONE 2019). In practice, data on incidence,

management, and long term cardiovascular (CV) consequences of Ibr-associated HTN are limited. As Ibr is administered continuously and HTN incidence is cumulative, this toxicity is understudied.

**Methods:** Multicenter, retrospective study of CLL pts treated with 420 mg Ibr for at least 6 months. We collected baseline CV comorbidities, CV medications (meds), blood pressure (BP) measurements prior to Ibr initiation and following exposure at specific times in a 12-month period, and adjustments to CV meds. Incident HTN is defined as BP > 140/90 mmHg, and worsening BP as sustained rise in SBP or DBP ≥ 3 mmHg over baseline.

**Results:** We identified 247 Ibr treated CLL pts. Pre-Ibr CV comorbidities included: HTN (43%), hyperlipidemia (35%), diabetes (16%), coronary artery disease (CAD; 9.7%), valvular heart disease (2.8%), atrial fibrillation (Afib; 4.5%), stroke (2.8%), and smoking history (42%). At least one anti-HTN med was used in 51% prior to Ibr initiation (median number of meds 1). Median BP prior to Ibr was 127/71 mmHg (range 92-174/48-95) and median pulse 75 bpm (range 27-110). Median peak BP following Ibr was significantly elevated (153/80 mmHg range 105-218/53-121, p<0.0001). Median time to peak BP was 6 months (range 0-35 months). Figure 1 depicts median systolic BP at baseline and 1, 3, 6, 9, and 12 months following Ibr initiation. During the observation period, 36% and 84% experienced new HTN or worsening of existing HTN respectively. 19.8% of pts required initiation of at least one new anti-HTN med, and 4.7% required increased dose of a pre-Ibr anti-HTN med. Of the 49 pts who required BP management, 86% started 1 new agent, and 14% started ≥2 new
<figure><img src="image_121.png" /><figcaption>**Figure 1.** Systolic blood pressure prior to ibratinib exposure and at sequential time points following ibratinib exposure.</figcaption></figure>

agents. The most common new classes of agents were beta blockers (32%), angiotensin receptor blockers (21%), diuretics (19%), calcium channel blockers (14%), and angiotensin converting enzyme inhibitors (14%). 6.4% experienced new onset Afib, 1.6% had CAD. Preexisting CV comorbidities, smoking history, and diabetes were not predictive of HTN development in univariate analyses.

**Conclusion:** HTN is a pervasive AE of Ibr affecting pts with and without baseline HTN or CV conditions. Physiologically, systolic BP appears to be more significantly affected than diastolic BP. While these data demonstrate 20% of pts adjust anti-HTN meds or start new ones, it is not known how effective current management is at controlling HTN or preventing long term vascular events. In addition, we demonstrate that the proportion of pts initiating new anti-HTN meds is significantly lower than those experiencing new/worsening HTN, identifying an opportunity for care optimization in partnership with cardio-oncology.

**Keywords:** BTK inhibitors; chronic lymphocytic leukemia (CLL); ibratinib.

**Disclosures:** Sarraf Yazdy, M: Consultant Advisory Role: Abbvie, Octapharma; Honoraria: Bayer. Schuster, S: Consultant Advisory Role: Novartis, Pharmacyclics, Celgene; Scientific Advisory Committees: Nordic Nanovector; Consultant: Genentech, Acerta; Research Funding: Gilead, Janssen Research & Development, Merck. Cheson, B: Consultant Advisory Role: AbbVie, Roche-Genentech, Pharmacyclics, Acerta, TG Therapeutics; Research Funding: Acerta, Pharmacyclics, Roche, AbbVie, TG Therapeutics. Mato, A: Consultant Advisory Role: Genentech, TG, PCYC, Loxo, Abbvie, Sunesis, Celegene, Verastem, AZ; Research Funding: TG, PCYC, Loxo, Abbvie, Sunesis, Regeneron, J and J.

165
AN IMPROVED BENEFIT-RISK PROFILE OF
DUVELISIB IN PATIENTS WITH CHRONIC
LYMPHOCYTIC LEUKEMIA OR SMALL
LYMPHOCYTIC LYMPHOMA WHO
RECEIVED 2 OR MORE PRIOR THERAPIES

I.W. Flinn¹ | M.S. Davids² | P. Hillmen³ |
M. Montillo⁴ | J. Delgado⁵ | B.J. Kuss⁶ | C.S. Tam⁷ |
U. Jäger⁸ | P. Ghia⁹ | S. Stilgenbauer¹⁰ |
S. Lustgarten¹¹ | D.T. Weaver¹¹ | H. Youssoufian¹¹ |
F. Cymbalista¹²

¹Lymphoma Research, Sarah Cannon Research Institute, Nashville, TN, United States; ²Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, United States; ³Experimental Haematology, St James's University Hospital, Leeds, United Kingdom; ⁴Department of Haematology and Oncology, Niguarda Cancer Center, Niguarda Hospital, Milan, Italy; ⁵Department of Hematology, Hospital Clinic, Barcelona, Spain; ⁶Molecular Medicine and Pathology, Flinders Medical Centre - Flinders University, Bedford Park, Australia; ⁷Division of Hematology and Oncology, Peter MacCallum Cancer Centre, St Vincent's Hospital and University of Melbourne, Melbourne, Australia; ⁸Division of Hematology and Hemostaseology, Department of Medicine, Medical University of Vienna, Wien, Austria; ⁹Università Vita-Salute San Raffaele, IRCCS Istituto Scientifico San Raffaele, Milan, Italy; ¹⁰Department III of Internal Medicine, University Hospital Ulm, Ulm, Germany; ¹¹Medical Affairs, Verastem Oncology, Needham, MA, United States; ¹²Laboratoire d'hématologie, Hôpital Avicenne, Paris, France

**Introduction:** Despite effective frontline therapies, many patients (pts) with CLL or SLL eventually relapse and require additional therapies to control their disease. Duvelisib (DUV), a first-in-class oral dual PI3K-δ,γ inhibitor, was approved by the FDA for the treatment of relapsed or refractory CLL or SLL after ≥2 prior therapies. Here we present the efficacy and safety of DUV in pts who had received ≥2 prior therapies in the phase 3 DUO trial (NCT02004522).

**Methods:** Pts were randomized 1:1 to oral DUV 25 mg BID or IV ofatumumab (OFA) 300 mg once, then 2000 mg for 12 doses total. The primary endpoint was PFS as assessed by a blinded IRC.

**Results:** Of the 319 total pts randomized, 191 had received ≥2 prior therapies (93 DUV; 98 OFA). In this population, the median number of prior therapies was 3 (range, 2-10). DUV was superior to OFA across all efficacy endpoints (Table). AEs occurring in >25% of pts who received DUV (all grade; grade ≥3) were diarrhea/colitis (58%; 24%), neutropenia (40%; 38%), pyrexia (33%; 2%), upper respiratory infection (30%; 0%), pneumonia (29%; 22%), and fatigue (26%; 3%). Many AEs were successfully managed through dose modifications, with dose reductions occurring in 28% of pts and dose interruptions occurring in 74% of pts who received DUV; diarrhea/colitis (10%) and neutropenia (5%) were the most common AEs leading to dose reduction. 22 pts (23%) discontinued DUV due to a related AE; diarrhea/colitis (n = 8), pneumonia (n = 3), and pneumonitis (n = 2) were the only treatment-related events leading to discontinuation in >1 pt. 11 pts (12%) treated with DUV experienced a fatal AE. The only fatal events to occur in >1 pt were hemorrhagic stroke (n = 2) and staphylococcal pneumonia (n = 2). AEs with OFA were similar to those previously reported.