Foss, Francine M.

TPS2657 Background: T-cell immunoreceptor with Ig and ITIM domains (TIGIT) is an inhibitory immune checkpoint receptor expressed on subsets of T cells and NK cells. SEA-TGT is an effector-function enhanced human mAb that targets TIGIT with pico-molar affinity and blocks TIGIT’s interaction with CD155 and CD112. SEA-TGT was developed to have amplified binding to and engagement of Fcγ receptors. Enhanced effector function increases TIGIT+ T-regulatory cell depletion, enhances innate immune cell activation, and augments naïve and memory CD8+ T-cell responses. Preclinically, SEA-TGT elicits superior anti-tumor immune responses compared to other TIGIT mAbs without effector-enhanced backbones, with curative anti-tumor activity as monotherapy and in combination with other immune-modulators. Methods: This phase 1, open-label, multicenter, dose-escalation/expansion study (NCT04254107) is assessing the safety, tolerability and preliminary activity of SEA-TGT monotherapy in up to 205 adults (≥18 years) with histologically or cytologically confirmed relapsed, refractory, or progressive metastatic solid tumors (non-small cell lung, gastric/GE junction carcinomas, cutaneous melanoma, head and neck squamous cell carcinoma, bladder cancer, ovarian cancer or triple-negative breast cancer) or lymphomas (classical Hodgkin lymphoma, diffuse large B-cell lymphoma, or peripheral T-cell lymphoma, not otherwise specified). SEA-TGT will be infused on Day 1 of 21-day cycles. In Part A, the safety and tolerability of SEA-TGT will be assessed in ̃25 subjects to identify the maximum tolerated dose and recommended phase II dose (RP2D). In Part B, the safety and antitumor activity of the RP2D will be assessed in ̃180 subjects in disease-specific expansion cohorts. Primary endpoints are adverse events, laboratory abnormalities, dose-limiting toxicities, and dose-level safety and activity. Secondary endpoints are objective response (OR) rates, duration of OR, complete response, progression-free survival, overall survival, PK, and antidrug antibodies. Exploratory biomarkers of SEA-TGT-mediated pharmacodynamic (PD) effects, PK-PD correlations, and correlative analyses of predictive and PD measurements with response, toxicity, and resistance will be explored. The study was opened April 2020 and is enrolling across sites in North America and Europe. Clinical trial information: NCT04254107.

Introduction T-cell prolymphocytic leukemia (T-PLL) is a rare and aggressive malignancy with limited treatment options, frequent relapse, and poor long-term survival. Allogeneic hematopoietic cell transplantation (allo-HCT) is reported to be effective in T-PLL yielding durable remissions and improved survival. Rates of survival and non-relapse mortality vary; data is scant and limited to small retrospective series. Whether regimen intensity - a modifiable factor- is associated with outcomes is unknown. Here, we report an analysis of patients with T-PLL undergoing allo-HCT in 87 centers using data reported to the Center for International Blood and Marrow Transplant Research (CIBMTR). Methods A retrospective multicenter study was conducted utilizing the CIBMTR dataset, which captures all consecutive patients transplanted in participating centers. The study population included patients aged 18 or older with T-PLL who underwent allo-HCT between 2008 and 2018. All donor types, graft sources, and conditioning intensities are summarized (Table 1). Cox regression analysis was used to assess overall mortality, treatment-related mortality (TRM), relapse or progression, disease-free survival (DFS) and acute and chronic graft-versus-host disease (GVHD). Due to the strong correlation between regimen intensity and patients' age, a combined variable was constructed, and in all models, interactions between age/regimen and significant covariates were examined. Results A total of 266 pts were identified and included in this analysis (Table 1). Median follow up of survivors was 49 months (range 3-117); the completeness of survival data out to four years was 95%. In univariate analysis, the 4-year overall survival (OS) rate was 30% (95% confidence interval [CI]: 23.8-36.5%). The 4-year DFS, relapse, TRM rates were 25.72% (95%CI: 20-32%), 41.9% (95%CI: 35.5-48.4%), and 32.4% (95%CI: 26.4-38.6%), respectively. Cumulative incidences of grade 2-4 acute GVHD at day +180 and chronic GVHD at 1-year were 22.5%% (95%CI: 16.8- 28.9%) and 38.3% (95%CI: 32.9-44.9%), respectively. Multivariate analyses was performed using age (Age >60 vs Age ≤60) and conditioning intensity (myeloablative [MAC] vs. reduced intensity/non-myeloablative [RIC/NMA]) as main effect (Table 2). Poor performance status was associated with inferior TRM, DFS and OS. Compared to MAC/Age ≤ 60, RIC/NMA/Age≤ 60 correlated significantly with less TRM (hazard ratio [HR] 0.28, 95% CI 0.14-0.55, p= 0.0022, superior DFS [HR 0.53, 95% CI 0.35-0.81, p= 0.0029; (Figure 3) and OS HR 0.49, 95% CI 0.32-0.75, p= 0.0009; (Figure 2). Similar trend was observed for RIC/NMA/ Age> 60 for all 3 outcomes but did not reach statistical significance. Remission status at time of allo-HCT (stable disease or progression vs. complete remission) correlated with relapse (hazard ratio [HR] of relapse=2.13, 95%CI 1.23-3.71, p=0.0072), however degree of response (partial response vs. complete remission did not significantly correlate with relapse (HR of relapse=1.41, 95%CI 0.91-2.17, p=0.1257). In vivo T cell depletion with ATG (N=47) or alemtuzumab (N=2) was associated with worse TRM [HR 1.82, 95% CI 1.08-3.08, p= 0.0255] and inferior DFS [HR of death or progression=HR 1.50, 95% CI 1.05-2.15, p= 0.0276]. The most common cause of death was disease relapse (52%) followed by infection (15%) and GVHD (13%). Conclusion This CIBMTR study, with the largest cohort of allo-HCT in T-PLL to date, demonstrates allo-HCT is effective in providing durable remissions. MAC and poor performance status were predictive of inferior TRM and OS. Disease relapse was most common cause of death, and pre-allo-HCT remission inversely correlated with relapse rate. The data suggest that reduced intensity conditioning and avoidance of post-transplant ATG/alemtuzumab may be beneficial. Novel strategies are needed both pre and post-allo-HCT to further improve outcomes. Disclosures Dholaria: J&J: Research Funding; bms: Research Funding; Takeda: Research Funding; Poseida: Research Funding; Angiocrine: Research Funding. Jagadeesh:Verastem: Membership on an entity's Board of Directors or advisory committees; Debiopharm Group: Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; MEI Pharma: Research Funding; Regeneron: Research Funding. Oran:Celgene: Consultancy; ASTEX: Research Funding; Arog Pharmaceuticals: Research Funding. Nakamura:Viracor: Consultancy; Celgene: Other: Support on seminar; Magenta Therapeutics: Other: Advisory board meeting; NapaJen Pharma: Consultancy; Alexion: Other: Support on a meeting presentation; Merck: Other: advisory board meeting; Kadmon Corporation: Other: Advisory board meeting; Kyowa-Kirin: Other: Support on a meeting presentation. Sauter:Spectrum Pharamaceuticals: Consultancy; Sanofi-Genzyme: Consultancy, Research Funding; Gamida Cell: Consultancy; Novartis: Consultancy; Genmab: Consultancy; Precision Biosciences: Consultancy, Research Funding; Kite - a Gilead Company: Consultancy; Celgene: Consultancy, Research Funding; GSK: Consultancy; Bristol-Myers Squibb: Research Funding; Juno Therapeutics: Consultancy, Research Funding. kharfan-Dabaja:Daiichi Sankyo: Consultancy; Pharmacyclics: Consultancy.

Introduction: With a median overall survival (OS) measured in months, successful treatment of Richter's transformation (RT) of chronic lymphocytic leukemia (CLL) to diffuse large B-cell lymphoma (DLBCL) remains a major unmet medical need. While targeted agents, such as Bruton tyrosine kinase inhibitor (BTKi) monotherapy, have greatly improved outcomes for patients (pts) with CLL and some B-cell lymphomas, available BTKi therapies have been ineffective for RT, as well as for large cell transformation of indolent B-cell lymphomas and relapsed/refractory (r/r) DLBCL, which rapidly develop mechanisms of resistance by activation of downstream targets of BTKi or upregulation of alternative/parallel pathways. Focusing on a synthetic lethality approach via in vitro and in vivo studies, we discovered that concurrent inhibition of BTK & mTOR targets plus an IMiD synergistically kill malignant B-cells. DTRM-555 is an optimized oral triple combination of a novel irreversible BTKi DTRMWXHS-12 (DTRM-12), everolimus (EV) and pomalidomide (POM). This once daily therapy was tested in a stepwise, phase I, multicenter study in pts with the greatest unmet medical needs. Here we present results for this novel combination therapy in pts with RT, and r/r DLBCL. Methods: We conducted a phase I (3+3 design), first in human trial exploring DTRM-555 in adult pts with B-cell lymphomas with no available standard therapies (NCT02900716) at 6 US cancer centers. Our goal was to determine the optimal dose for DTRM-555. In phase Ia, an MTD was not reached for DTRM-12 monotherapy; In phase Ib and expansion cohorts, we evaluated double (DTRM-12/EV at 200mg/5mg or 300mg/5mg) and triple combinations (DTRM-12/EV/POM at 200mg/5mg/2mg or 300mg/5mg/2mg) administered once daily for 21 days of a 28-day cycle, until disease progression or unacceptable toxicity. The primary endpoint was safety and the dose limiting toxicity (DLT) period was cycle 1 (28 days). Secondary endpoints included overall response rate (ORR; Cheson 2014), duration of response (DOR), and DTRM-12 pharmacokinetics. The trial began on 9/27/2016 and completed enrollment with evaluable follow-up data cut-off date on 08/06/2020. Results: 39 pts were enrolled and treated, including 24 with RT (n=12) or r/r DLBCL (n=12). The safety analyses included all 39 pts treated with combination therapies while efficacy analyses were focused on RT and r/r DLBCL. Baseline characteristics (n=39): 66% male, median age 71 years (range 43-94) and 94% white. For the entire study cohort, median number of prior therapies was 3 (range 1-10), 49% had been treated with prior BTKi monotherapy,13% prior CAR-T or stem cell transplant (SCT) and 59% ≥1 prior small molecule targeted agent. For pts with RT and r/r DLBCL (n=24), median prior therapies were 5 (range 1-10) and 2 (range 10), respectively. Table 1 summarizes prior therapies for the 24 RT and r/r DLBCL pts. Table 2 describes Grade 3 and 4 related AEs for 39 pts treated with the combination therapies. AEs were manageable and similar to known AEs for BTKi, EV or POM, with a total of 4 DLTs observed with combination therapies. The most common AEs were hematological events; specifically, thrombocytopenia, neutropenia, and anemia. The MTD of DTRM-555 was determined to be DTRM-12 200mg, EV 5mg, & POM 2mg. For 11 evaluable RT pts, ORR was 45% (1 CR, 4 PR); 1 RT pt has not undergone first response assessment. For 10 evaluable DLBCL pts, ORR was 60% (2 CR, 4 PR). Responders with RT or r/r DLBCL have durable responses (Figure 1). Kaplan Meier estimated median duration of response for RT and DLBCL pts was 15 months as of the cut-off. Dose dependent DTRM-12 drug plasma levels were observed in all arms with minimal inter-pt variability. Conclusions: This clinical trial met its primary endpoint. The once-daily oral triple combination therapy DTRM-555 has an acceptable safety profile. Encouraging clinical activity was observed in several high-risk, multi-refractory pts with RT (median 5 prior therapies, ORR 45%) or r/r DLBCL (median 2 prior therapies, ORR 60%), including pts previously treated with targeted therapies, cellular therapies, checkpoint inhibitors and other experimental agents. A phase II US expansion study is underway targeting pts with RT, r/r DLBCL, r/r transformed follicular lymphoma and BTKi/BCL2 inhibitor exposed r/r CLL pts. Disclosures Mato: Adaptive: Consultancy, Research Funding; TG Therapeutics: Consultancy, Other: DSMB, Research Funding; AbbVie: Consultancy, Research Funding; AstraZeneca: Consultancy, Research Funding; BeiGene: Consultancy; LOXO: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding. Schuster:AlloGene, AstraZeneca, BeiGene, Genentech, Inc./ F. Hoffmann-La Roche, Juno/Celgene, Loxo Oncology, Nordic Nanovector, Novartis, Tessa Therapeutics: Consultancy, Honoraria; Novartis, Genentech, Inc./ F. Hoffmann-La Roche: Research Funding. Ding:DTRM: Research Funding; Astra Zeneca: Research Funding; Abbvie: Research Funding; Octapharma: Membership on an entity's Board of Directors or advisory committees; MEI Pharma: Membership on an entity's Board of Directors or advisory committees; alexion: Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding. Brander:Tolero: Research Funding; NCCN: Other; Teva: Consultancy, Honoraria; Novartis: Consultancy, Other; NCCN: Other; Verastem: Consultancy, Honoraria, Other, Research Funding; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; Pfizer: Consultancy, Other; Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Other, Research Funding; MEI Pharma: Other, Research Funding; Juno/Celgene/BMS: Other, Research Funding; Genentech: Consultancy, Honoraria, Other, Research Funding; DTRM: Other, Research Funding; AstraZeneca: Consultancy, Honoraria, Other, Research Funding; BeiGene: Other, Research Funding; Ascentage: Other, Research Funding; ArQule: Consultancy, Other, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; Tolero: Research Funding; Teva: Consultancy, Honoraria; Novartis: Consultancy, Other. Tun:Bristol-Myers Squibb: Research Funding; Celgene: Research Funding; Mundipharma: Research Funding; Curis: Research Funding; TG Therapeutics: Research Funding; Acrotech: Research Funding; DTRM Biopharma: Research Funding. He:DTRM Biopharma LLC: Current Employment. Kearney:DTRM Biopharma LLC: Current Employment. Gui:DTRM Biopharma LLC: Current Employment. McKinlay:DTRM Biopharma LLC: Current Employment. Roeker:American Society of Hematology: Research Funding; AbbVie: Other: spouse with minority ownership interest ; Abbott Laboratories: Other: spouse with minority ownership interest . Huntington:Pharmacyclics: Honoraria; Novartis: Consultancy; Genentech: Consultancy; DTRM: Research Funding; AbbVie: Consultancy; Astrazeneca: Honoraria; Bayer: Consultancy, Honoraria; Celgene: Consultancy, Research Funding; TG Therapeutics: Research Funding.

Targeted agents have greatly improved outcomes for patients (pts) with chronic lymphocytic leukemia (CLL) and other B cell lymphomas; however, single agents have been limited by intolerance, resistance and depth/durability of responses. Current novel targeted agent combinations may improve depth of response, but such "full dose" strategies have been associated with significant AEs, dose reductions/interruptions and discontinuations. Our in vitro & in vivo screening/optimization studies identified that concurrent inhibition of BTK & mTOR targets plus IMiD at low doses of each inhibitor can synergistically kill B-cell malignancies and may address drug-resistance. DTRM-555 is an optimized oral triplet combination of a novel BTK inhibitor DTRMWXHS-12 (DTRM-12) with everolimus (EV) & pomalidomide (POM). This once daily therapy was tested in a stepwise, phase I, US multicenter study in patients with highest unmet medical needs including r/r CLL, Richter's transformation (RT) of CLL, DLBCL, transformed B-cell lymphomas. We conducted a 3+3 design phase I, first human trial exploring DTRM-555 in pts ≥18 years, ECOG PS ≤1 with CLL, B-cell NHL, or Hodgkin lymphoma (HL) with no available standard therapy (NCT02900716). Our goal was to determine optimal doses for triplet combination therapy through 3 escalating phases of study: DTRM-12 in escalating doses (50, 100, 200, & 300 mg/day) in Part Ia, DTRM-12 at 200 mg or 300 mg & EV at 5 mg (doublet or DTRM-505) in Part Ib Arm A while DTRM-12 at 200 mg or 300 mg, EV at 5 mg & POM at 2 mg in Part Ib Arm B. For all arms, treatment was administered for 21 consecutive days of a 28-day cycle, until disease progression or unacceptable toxicity. Safety was the primary endpoint, and the dose-limiting toxicity (DLT) period was cycle 1. Secondary endpoints included response (iwCLL 2018 or Cheson 2014), progression free survival, duration of response and pharmacokinetics. Intra-patient migration between arms (Mono to doublet to triplet) was permitted if subsequent doses were tolerated. The trial commenced 9/27/2016 and completed enrollment 7/25/2019. Thirty-three pts were enrolled, including 2 screen failures and 4 intra-cohort migrations, with r/r DLBCL (n=8), CLL/SLL (n=5), RT (n=6), FL (n=5), MCL (n=4), MZL/LPL (n=3), HL (n=2). 30 of 31 treated pts were evaluated: 8 pts participated in phase Ia (DTRM-12) while 23 pts were treated on phase Ib combinations (DTRM-505 & DTRM-555). Baseline characteristics: 70% male (n=23), median age 70 years (range 46-94) and 94% white. Median prior therapies were 3 (range 1-10), 53% had been treated with ≥1 prior targeted agent (i.e., CD19/CD3 bispecific antibody, obtinutuzumab, pembrolizumab, nivolumab, ibrutinib, venetoclax, PI3k-i), CAR-T or HSCT. 35% pts were previously treated with ibrutinib. Table 1 describes Grade (Gr) 3 and 4 AEs (all causality, stratified by treatment arm). Regarding safety, AEs were manageable, with a total of 5 DLTs were observed: 2 (Gr 3 febrile neutropenia, URI) in part Ib arm A, 3 (Gr 4 thrombocytopenia, Gr 3 diarrhea, G3 febrile neutropenia) in Part Ib arm B. No MTD was reached for the mono & doublet arms, with the MTD of the triplet determined to be DTRM-12 200 mg, EV 5 mg, & POM 2 mg. Spider plot (Figure 1a) shows the clinical response for individual CLL and lymphoma pts treated with mono, doublet and triplet therapies. Depth and durability of response improved with combination therapies (vs. mono). Of note, 48% of all patients had a ≥50% reduction in sum of the products of lymph node diameters. Representative PET-CT scans are in Figure 1b-c. Responses in multi-refractory pts are ongoing (including 15+ mos in a pt with r/r DLBCL and 5+ mos PR in a pt aged > 90 yrs with r/r DLBCL; 4+ & 13+ mos PRs in two pts with RT). DTRM-12 plasma concentrations were unaffected by EV & POM (Once Daily Oral Therapies) in Figure 1d. The clinical trial met its primary endpoint as the triple combination DTRM-555 had an acceptable safety profile. Dose dependent drug levels with minimal inter-pt variations were observed in all arms, supporting once daily oral administration of this low-dose combination therapy. Encouraging clinical activity was observed in several high-risk, multi-refractory CLL and lymphoma pts, including those previously treated with ibrutinib. Thus synthetic lethality is a viable treatment approach. A phase II US expansion study is underway targeting pts with transformed lymphomas (follicular or prior CLL) and r/r DLBCL cohorts. Table 1. Disclosures Mato: AbbVie: Consultancy, Research Funding; Sunesis: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Johnson & Johnson: Consultancy, Research Funding; Celgene: Consultancy; AstraZeneca: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; Gilead: Research Funding; Acerta: Consultancy; Janssen: Consultancy; TG Therapeutics: Consultancy, Other: DSMB member , Research Funding; LOXO: Consultancy, Research Funding; DTRM Biopharma: Research Funding. Schuster:DTRM Biopharma: Research Funding. Foss:Mallinckrodt: Consultancy; Acrotech: Consultancy; miRagen: Consultancy; Seattle Genetics: Consultancy, Other: fees for non-CME/CE services ; Eisai: Consultancy; Spectrum: Other: fees for non-CME/CE services . Isufi:Novartis: Consultancy; Astra Zeneca: Consultancy; Celgene: Consultancy. Ding:Merck: Research Funding; DTRM Biopharma: Research Funding. Brander:Novartis: Consultancy; MEI: Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy; BeiGene: Research Funding; AstraZeneca: Consultancy, Research Funding; Acerta: Research Funding; Tolero: Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; Genentech: Consultancy, Honoraria, Research Funding; Teva: Consultancy, Honoraria; TG Therapeutics: Consultancy, Honoraria, Research Funding; DTRM Biopharma: Research Funding. Tun:Mundi-pharma: Research Funding; TG Therapeutics: Research Funding; Curis: Research Funding; DTRM Biopharma: Research Funding; Celgene: Research Funding; BMS: Research Funding. He:DTRM Biopharma: Employment, Equity Ownership. Kearney:DTRM Biopharma: Employment, Equity Ownership. Gui:DTRM Biopharma: Employment, Equity Ownership. Anderson:Theradex: Employment. Roeker:AbbVie: Equity Ownership; Abbott Laboratories: Equity Ownership. Huntington:Bayer: Consultancy, Honoraria; AbbVie: Consultancy; Celgene: Consultancy, Research Funding; Genentech: Consultancy; Pharmacyclics: Honoraria; DTRM Biopharm: Research Funding. OffLabel Disclosure: Everolimus in B cell lymphomas and CLL Pomalidomide in B cell lymphomas and CLL

Abstract Background Tipifarnib is a potent and selective inhibitor of the enzyme farnesyltransferase (FT). FT catalyzes post-translational attachment of farnesyl groups required for localization of signaling molecules to the inner cell membrane. CXCL12 is a chemokine that is essential for T cell homing to lymphoid organs and the bone marrow, and for the maintenance of immune cell progenitors. Herein we report preliminary efficacy, safety and biomarker data from a Phase 2 study of tipifarnib in angioimmunoblastic T-cell lymphoma (AITL) and CXCL12+ peripheral T-cell lymphoma (PTCL) patients (pts). Methods This Phase 2 study is a multi-institutional, single-arm, open-label trial initially designed as a two-stage (11+7 pts) cohort to determine the efficacy, safety and biomarkers of tipifarnib in pts with relapsed/refractory (R/R) PTCL, age >/=18 years and a performance status of 0-2. Based on initial findings, the study was amended to include a cohort of AITL (n=12) and PTCL (n=12) pts with the CXCL12 rs2839695 A/A genotype (CXCL12+ cohort). Pts received tipifarnib 300 mg administered orally twice daily on days 1-21 of 28-day treatment cycles until progression of disease (PD) or unacceptable toxicity. The primary endpoint of the study is overall response rate (ORR). Ancillary studies are also ongoing to investigate the prognostic value of CXCL12 expression in patients who received standard of care treatment. Results As of 25 July 2018, 34 PTCL pts (13 AITL, 1 ALK- ALCL, 20 PTCL-NOS) have been treated with tipifarnib, 19 pts in stages 1 and 2, and 15 pts in the ongoing AITL histology and CXCL12 cohorts. Median number of prior treatment regimens was 3. The most common treatment-related adverse events (AE) (grade ≥ 3) are hematological, including neutropenia (50%), thrombocytopenia (43%), leukopenia (33%), febrile neutropenia (27%), and anemia (20%). Skin and subcutaneous tissue disorders were reported in 9 pts, 6 of them with AITL histology. One pt with AITL experienced an episode of possible Stevens Johnson Syndrome that resolved with dose discontinuation and did not recur upon re-challenge at one dose level reduction. Of 18 evaluable patients enrolled in Stages 1 and 2 of the trial, 3 partial responses (PR), 2 of them in pts with AITL histology, and 4 best responses of stable disease (SD) were observed. Pre-treatment tumor tissue CXCL12 expression correlated with favorable pt outcomes. In the AITL cohort (10 evaluable pts), 1 PR and 1 SD have been observed so far, with 5 pts pending cycle 2 response evaluation. In the CXCL12+ cohort (n=3 evaluable pts), 1 SD has been observed, with 2 pts pending cycle 2 response evaluation. Plasma levels of CXCL12 decreased over time with tipifarnib treatment. Expression of CXCL12 mRNA and other biomarkers in pre-treatment biopsies of pts in the AITL and CXCL12+ cohorts are being evaluated using RT-PCR assays. In addition, the prognostic value of CXCL12 is being investigated in approximately 100 diagnostic specimens of PTCL pts who received standard therapy. Preliminary data suggest that CXCL12 overexpression is observed in approximately 25% of PTCL and negatively affects pt survival. Conclusion Preliminary activity of tipifarnib was observed in PTCL pts, particularly in those with tumors of AITL histology and high CXCL12 expression and enrollment continues. Disclosures Witzig: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Sokol:Mallinckrodt Pharmaceuticals: Consultancy; Seattle Genetics: Consultancy; Spectrum Pharmaceuticals: Consultancy. Jacobsen:Merck: Consultancy; Seattle Genetics: Consultancy. Kim:Takeda: Research Funding; J&J: Research Funding; Mundipharma: Research Funding; Roche: Research Funding; Novartis: Research Funding; Kyowa-Kirin: Research Funding; Celltrion: Research Funding. Foss:Miragen: Consultancy, Speakers Bureau; Spectrum: Consultancy; Seattle genetics: Consultancy; Mallinkrodt: Consultancy. Advani:Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Kura: Research Funding; Merck: Research Funding; Roche/Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding; Kyowa: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Regeneron: Research Funding; Janssen: Research Funding; Bayer: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Cell Medica: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Astra Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Autolus: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding; Gilead/Kite: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Millenium: Research Funding; Agensys: Research Funding; Celgene: Research Funding; Forty Seven: Research Funding; Infinity: Research Funding. Marin Niebla:Amgen: Other: Medical education of Staff, Speakers Bureau; Roche: Consultancy, Other: Medical education of Staff, Speakers Bureau; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Other: Medical education of Staff, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Medical education of Staff, Speakers Bureau. Piris:Kura: Honoraria; Takeda: Honoraria; Janssen: Honoraria; Gilead: Honoraria. Curry:Kura Oncology: Employment, Equity Ownership. Gualberto:Kura Oncology: Employment, Equity Ownership.

Background:Tipifarnib is a potent and selective inhibitor of the enzyme farnesyltransferase (FT). FT catalyzes post‐translational attachment of farnesyl groups required for localization of signaling molecules to the inner cell membrane. CXCL12 is a chemokine that is essential for T cell homing to lymphoid organs and the bone marrow, and for the maintenance of immune cell progenitors.Aims:Herein we report preliminary efficacy, safety and biomarker data from a Phase 2 study of tipifarnib in angioimmunoblastic T‐cell lymphoma (AITL) and CXCL12+ peripheral T‐cell lymphoma (PTCL) patients (pts).Methods:This Phase 2 study (NCT02464228) is a multi‐institutional, single‐arm, open‐label trial initially designed as a two‐stage (11+7 pts) design to determine the efficacy, safety and biomarkers of tipifarnib in pts with relapsed/refractory (R/R) PTCL age >/ = 18 years and a performance status of 0–2. Based on initial findings, the study was amended to include a cohort of AITL (n = 12) and PTCL (n = 12) pts with the CXCL12 rs2839695 A/A genotype (CXCL12+ cohort). Pts received tipifarnib 300 mg administered orally twice daily on days 1–21 of 28‐day treatment cycles until progression of disease (PD) or unacceptable toxicity. The primary endpoint of the study is overall response rate (ORR). Ancillary studies are also ongoing to investigate the prognostic value of CXCL12 expression in pts who received tipifarnib and standard of care treatment.Results:As of 20 February 2019, 43 PTCL pts (20 AITL, 21 PTCL‐NOS, 1 ALK‐ ALCL, 1 gamma‐delta TCL) have been treated with tipifarnib, 19 pts in stages 1 and 2, and 24 pts in the ongoing AITL histology and CXCL12 cohort. Median number of prior treatment regimens was 3; 19 pts had a prior stem cell transplant. All pts had at least one treatment‐emergent adverse event (TEAE); 39 (90%) had at least 1 study drug‐related TEAE and 12 (28%) at least 1 drug related SAE. The most frequently observed drug‐related TEAEs of Grade ≥3 occurring in 10% or more of pts were blood and lymphatic system disorders, including neutropenia (44%), thrombocytopenia (37%), leukopenia (28%), anemia (21%) and febrile neutropenia (21%). There have been 14 deaths on study; none were related to study drug. Of 18 evaluable pts enrolled in Stages 1 and 2 of the trial, 3 partial responses (PR), 2 of them in pts with AITL histology, and 4 best responses of stable disease (SD) were observed. In the AITL cohort (11 evaluable pts), a 45% ORR and 73% clinical benefit rate (CBR; 3 CR, 2 PR and 3 SD) was observed. In the CXCL12+ cohort (n = 3 evaluable pts), 1 PR and 2 SD have been observed, with 4 pts pending cycle 2 response evaluation. CXCL12 expression correlated with favorable outcome to tipifarnib treatment. Pre‐treatment high CXCL12 expression had 90% sensitivity and 93% specificity to identify pts who experienced CR/PR/SD on study in a preliminary analysis of 24 pts. The prognosis of CXCL12 was also retrospectively investigated in 73 pts who received standard of care therapy (AITL N = 50, PTCL NOS = 23). A trend for poor prognosis (22 vs 40 months median OS from diagnosis, HR = 1.8, p = 0.09) was observed using the high CXCL12 subset using the cut‐off point that predicted clinical benefit under tipifarnib therapy. Fifty percent of AITL and 35% of non‐AITL samples overexpressed CXCL12.Summary/Conclusion:Preliminary activity of tipifarnib was observed in PTCL pts, particularly in those with tumors of AITL histology and high CXCL12 expression and enrollment in the CXCL12+ cohort continues.