Halwani, Ahmad

AbstractBackgroundPrimary cutaneous γδ T‐cell lymphoma (CGD‐CTL) is a rare malignancy that classically exhibits an aggressive clinical phenotype.ObjectivesReview cases of mycosis fungoides with a γδ phenotype that demonstrated an indolent clinical course.MethodsRetrospective review of patients diagnosed with MF with a γδ phenotype and an indolent clinical course between 2018 and 2022 treated at the University of Utah.ResultsFive patients ages 4‐81 years old were identified. All presented with clinically persistent patch or plaque‐stage disease, and histopathology showed primarily epidermotropic infiltrates positive for TCR delta via immunostaining. None of these patients have required aggressive treatment with multiagent chemotherapy.ConclusionsThere exists a subset of indolent CGD‐TCL patients who are clinicopathologically distinct from classic CGD‐CTL and clinically resembling indolent MF. Therefore, we prefer the term “MF with γδ phenotype” for these rare cases.

Background: CLL is the most prevalent adult leukemia with a highly heterogenous genetic landscape leading to extremely varied clinical outcomes. Previously, CLL patients with immunoglobulin heavy chain variable region ( IGHV) mutated status and presence of deletion 13q14 [del(13q)] were identified as favorable-risk with most patients remaining on lifetime observation. However, other intrinsic factors contributing to CLL disease progression and leading to treatment initiation remain unknown. Our goal was to identify patients at high-risk of progression with added predictive value (APV) beyond IGHV-status and presence of del(13q). Methods: Flow cytometry was used to sort CD19+CD5+ malignant cells in peripheral blood from CLL patients at Huntsman Cancer Institute at University of Utah and triple sequencing generated (tumor whole transcriptome and paired tumor-normal whole exome data). We used SPECTRA, a novel dimension reduction transcriptome approach, to derive a set of independent, intrinsic, quantitative transcriptome tumor variables from 249 CLL patients with quality-controlled transcriptome sequence data. From this set, 182 treatment-naïve (TN) patients with quality-controlled clinical variables were used as a discovery cohort set to derive a SPECTRA-based risk score for TTFT using multivariable Cox proportional hazards modeling. Event time was date of patient specimen acquisition to initiation of frontline therapy with patients censored at last follow-up or death. Gaussian mixture modeling (GMM) was performed to identify evidence for distinct risk groups within the quantitative risk score. GMM-risk groups, and further stratifications by IGHV mutational and del(13q) status, were used in hazard ratios (HR) and to illustrate differences in Kaplan-Meier time-to-event curves. An independent publicly available dataset of 548 TN CLL patients with clinical and transcriptome data for CD19+ enriched cells was used for replication. Results: SPECTRA produced 19 quantitative spectra variables to describe most of the expression variation across the 249 CLL patients. In multivariable Cox modeling for TTFT, 7 spectra were significant and retained in a final model, which GMM separated into a bi-modal distribution and defined high (N=83) and low-risk (N=99) groups (HR=5.7, 95% confidence interval [CI] 3.4-9.7). In a post-hoc model including IGHV mutational and del(13q) status, the spectra-risk score showed significant APV beyond both factors (p<0.001 for both). The discovery study timeframe was 6.3 years (y) and included 109 IGHV-mutated and 75 del(13q) patients. In the IGHV-mutated patients, median TTFT (mTTFT) was significantly shorter for spectra-high risk patients (3.1y) vs. spectra-low risk patients (median not reached [NR]; p<0.001). Similarly, in the del(13q) patients, mTTFT was significantly shorter in high-risk patients (3.3y) compared to median NR for spectra-low (p<0.001) ( Figure). Importantly, stratification of patients into low- and high-risk SPECTRA scores provided significant additional information for prediction of TTFT than IGHV mutational and del(13q) status ( Figure). For validation, we applied the same spectra-risk score to the independent data set containing 301 IGHV-mutated and 278 del(13q) CLL patients. In the replication set, the mTTFT in the IGHV-mutated patients who were spectra-high was 3.3y vs. 11.2y in spectra-low (p<0.001). Similarly, in the replication set of del(13q) patients, spectra-high-risk patients had a mTTFT of 2.7y vs. 10.7y for spectra-low (p<0.001). Conclusion: A transcriptome risk score utilizing novel SPECTRA variables identified a substantial subset of CLL patients with IGHV-mutated status and presence of del(13q) who have uncharacteristically short TTFT, but who would be classified as favorable risk under current best practice stratification. Future directions include validating our results with external patient cohorts from Mayo Clinic and investigating the genetic and transcriptomic profile of SPECTRA low- and high-risk cohorts to determine targetable pathways for treatment.

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of lymphoproliferative disorders arising from mature T cells, accounting for about 10% of non-Hodgkin lymphomas. PTCL-not otherwise specified is the most common subtype, followed by angioimmunoblastic T-cell lymphoma, anaplastic large cell lymphoma, anaplastic lymphoma kinase–positive, anaplastic large cell lymphoma, anaplastic lymphoma kinase–negative, and enteropathy-associated T-cell lymphoma. This discussion section focuses on the diagnosis and treatment of PTCLs as outlined in the NCCN Guidelines for T-Cell Lymphomas.

Hepatosplenic T-cell lymphoma (HSTCL) is a rare subtype of T-cell lymphoma associated with an aggressive clinical course and a worse prognosis. HSTCL develops in the setting of chronic immune suppression or immune dysregulation in up to 20% of cases and is most often characterized by spleen, liver, and bone marrow involvement. Diagnosis and management of HSTCL pose significant challenges given the rarity of the disease along with the absence of lymphadenopathy and poor outcome with conventional chemotherapy regimens. These Guidelines Insights focus on the diagnosis and treatment of HSTCL as outlined in the NCCN Guidelines for T-Cell Lymphomas.

Mycosis fungoides (MF) is the most common subtype of cutaneous T-cell lymphoma (CTCL), and Sézary syndrome (SS) is a rare erythrodermic and leukemic subtype of CTCL characterized by significant blood involvement. Although early-stage disease can be effectively treated predominantly with skin-directed therapies, systemic therapy is often necessary for the treatment of advanced-stage disease. Systemic therapy options have evolved in recent years with the approval of novel agents such as romidepsin, brentuximab vedotin, and mogamulizumab. These NCCN Guidelines Insights discuss the diagnosis and management of MF and SS (with a focus on systemic therapy).

TPS3113 Background: Programmed death-1 (PD-1) is an immune checkpoint receptor that inhibits T-cell activation upon interaction with its ligands PD-L1 or PD-L2. Increased PD-L1 expression has been reported with various hematologic malignancies and may prevent the host immune response from exerting an antitumor effect on the malignant cells. Nivolumab, a fully human IgG4 monoclonal PD-1 receptor blocking antibody, has demonstrated antitumor activity in pts with solid tumors including melanoma, renal cell carcinoma, and non-small cell lung carcinoma. We hypothesized that nivolumab could also mediate antitumor activity in pts with hematologic malignancies, a significant area of unmet medical need. We describe a phase I study to evaluate the effects of nivolumab in pts with select hematologic malignancies. Methods: This open-label, two-part study will enroll approximately 100 pts. During dose escalation, successive cohorts of pts with relapsed or refractory hematologic malignancies will be treated using a 6+3 escalation design. Pts will receive 1 or 3 mg/kg nivolumab IV every 2 weeks (wks) (the first dose will be followed by a 3-wk evaluation period), for 2 years, with the potential for an additional year of therapy for pts who progress during the follow-up period. Subsequently, 5 tumor-specific cohorts of 16 pts will be enrolled at the maximum tolerated dose (MTD) for multiple myeloma, B-cell lymphoma, T-cell lymphoma, Hodgkin lymphoma/primary mediastinal B-cell lymphoma, and chronic myelogenous leukemia. Response will be assessed at wks 4, 8, 16, 24, and every 16 wks thereafter. The primary study objective is to establish dose limiting toxicities, the MTD, and the recommended phase II nivolumab dose. Secondary objectives are to characterize nivolumab pharmacokinetics, immunogenicity, preliminary antitumor activity, and the potential association between PD-L1 expression on tumor cells and clinical efficacy. Exploratory objectives include investigation of the immunoregulatory effects of nivolumab in peripheral blood, bone marrow, and/or tumor. Pts are currently being enrolled at 3 mg/kg. Clinical trial information: NCT01592370.

Abstract Introduction: Classical Hodgkin lymphoma (cHL) is characterized by Reed Sternberg (RS) cells surrounded by an extensive but ineffective inflammatory/immune cell infiltrate. Recent studies suggest that Hodgkin RS cells have developed mechanisms that exploit the programmed cell death-1 (PD-1) pathway to evade immune detection. In cHL, chromosome 9p24.1 gain is a frequent structural alteration that increases the gene dosage of the PD-1 ligands, PD-L1 and PD-L2, and their induction via JAK/STAT signaling. Epstein-Barr Virus (EBV) infection also increases the expression of the PD-1 ligands in EBV-positive cHL. Ligand binding to PD-1 receptor-positive activated T cells induces “T cell exhaustion,” a reversible inhibition of T cell activation and proliferation. Nivolumab (BMS-936558, Bristol-Myers Squibb) is a fully human IgG4 monoclonal PD-1 blocking antibody that potentiates anti-tumor T cell activity, and exhibits clinical efficacy in several solid tumors. We hypothesized that nivolumab may augment anti-tumor activity in patients with relapsed or refractory (R/R) cHL, including those who had failed brentuximab vedotin (BV), and evaluated the PD-1 blocking antibody. These are the first analyses being reported with PD-1 antibody for the treatment of cHL. Methods: Patients with R/R cHL were included as an independent cohort in a dose escalation and cohort expansion phase I study of nivolumab in lymphoma and multiple myeloma (MM). Results for patients with non-Hodgkin lymphoma and MM are reported separately. Patients with cHL received nivolumab 3 mg/kg every 2 weeks until confirmed tumor progression or excessive toxicity. Responses were evaluated using standard criteria. The primary endpoint was safety; key secondary endpoints included anti-tumor activity and expression of immunomodulatory proteins in tumor biopsies. Results: Twenty-three patients were enrolled with R/R cHL. Patients were heavily pre-treated, 87% had received ≥ 3 prior treatment regimens, 78% had prior autologous stem cell transplant (ASCT), and 78% had prior BV treatment. Drug-related adverse events (AEs) of any grade occurred in 78% of patients, the most common of which were rash (22%), decreased platelet count (17%), diarrhea, nausea, pruritus, fatigue, and pyrexia (each at 13%). Drug-related grade 3/4 AEs occurred in 22% of patients. Three patients experienced 1 serious AE each (grade 3 myelodysplastic syndrome [MDS], grade 3 pancreatitis, and grade 2 lymph node pain). The objective response rate (ORR) was 87% (20/23), with 4 patients (17%) achieving a complete response (CR) and 16 (70%) obtaining a partial response (PR). The remaining 3 patients (13%) had stable disease (SD). All 23 patients had a reduction in tumor burden at 1 or more efficacy assessments during treatment with nivolumab (Figure). Among the 18 patients who had previously failed BV, the ORR was 89% (16/18), with 6% (1/18) achieving CR and 83% (15/18) PR. Progression-free survival (PFS) rate at 24 weeks was 86% (95% CI, 62-95%). The median overall survival (OS) has not been reached (range, 21+ to 75+ weeks). Six of 23 patients elected to discontinue study treatment to undergo stem cell transplantation, 2 patients discontinued due to toxicities (MDS and thrombocytopenia in 1 patient; pancreatitis in 1 patient), 4 patients discontinued due to disease progression, and 11 patients continue on study as of June 16, 2014. In a subset of study patients (10/23), PD-L1 and PD-L2 copy numbers in RS cells were assessed using fixed tumor biopsy specimens and a 3-probe fluorescence in situ assay (PD-L1,PD-L2, and control centromeric probe). In all tumors, RS cells had copy gains of PD-L1 and PD-L2, as a result of either polysomy or amplification; these tumors also exhibited increased protein expression of PD-L1. RS cells were also largely positive for pSTAT3, indicative of active JAK/STAT signaling. Conclusions In patients with R/R cHL, nivolumab-mediated PD-1 blockade is safe and tolerable with a safety profile similar to that in solid tumors. The frequent and long-lasting responses in heavily pretreated, R/R patients, including those who have failed BV, highlight the importance of the PD-1 pathway in cHL, and the genetically defined sensitivity to PD-1 blockade in this disease. Based on these results, the FDA granted nivolumab breakthrough status in relapsed cHL and a large, multinational, phase II trial of this therapy is underway. Figure 1 Figure 1. Disclosures Armand: Merck: Consultancy. Off Label Use: Nivolumab was tested for the treatment of hematologic malignancies.. Ansell:Bristol-Myers Squibb: Research Funding. Lesokhin:Bristol-Myers Squibb: Consultancy, Research Funding. Timmerman:Bristol-Myers Squibb: Research Funding. Borrello:Bristol-Myers Squibb: Research Funding. Rodig:Bristol-Myers Squibb: Research Funding. Zhu:Bristol-Myers Squibb: Employment. Grosso:Bristol-Myers Squibb: Employment, Equity Ownership. Kim:Bristol-Myers Squibb: Employment. Shipp:Merck: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; Sanofi: Research Funding; Janssen R&D: Membership on an entity's Board of Directors or advisory committees.

Abstract Introduction DLBCL is the most common lymphoid neoplasm in adults (Swerdlow 2016). While durable CRs are achieved in approximately 70% of patients (pts) with frontline RCHOP therapy (Pfreundschuh 2008), pts with high-risk features often experience disease resistance or relapse. In Part 1 of an ongoing study, pts with high-intermediate or high risk DLBCL by international prognostic index (IPI) scores, regardless of CD30 expression by IHC, were treated with 1.2 or 1.8 mg/kg brentuximab vedotin (BV) combined with RCHOP. After 3 of the first 10 pts treated at 1.8 mg/kg BV+RCHOP developed Grade 3 peripheral neuropathy (per Standardized MedDRA Query [SMQ]), all pts enrolled subsequently received treatment with 1.2 mg/kg BV+RCHOP. Following completion of enrollment in Part 1, the protocol was amended to enroll a non-randomized portion of the study (Part 2) evaluating the safety and efficacy of 1.8 mg/kg BV+RCHP (Yasenchak 2015), followed by an open-label, randomized portion comparing BV+RCHP to RCHOP (Part 3). Initial results from Part 2 and updated results from Part 1 are reported here. Methods For Part 2 of the study, pts with CD30-expressing high-intermediate and high-risk DLBCL were treated with up to 6 cycles of 1.8 mg/kg BV+RCHP (NCT01925612). Key inclusion criteria were CD30 expression by IHC performed by a local pathology lab and standard IPI scores of 3-5 or age-adjusted IPI (aaIPI) scores of 2-3 (high-intermediate/high risk). CD30 expression was confirmed by a central pathology lab, although CD30 expression by local pathology lab was required for eligibility. Disease response was evaluated with PET/CT per Cheson 2007. Results At the time of analysis for this ongoing study, 11 pts in Part 2 were treated with BV+RCHP (7 male, 4 female; 22-78 yrs). Of these pts, 9 had high-intermediate risk (IPI 3, aaIPI 2) and 2 had high risk disease (IPI 4-5, aaIPI 3), 6 had Stage IV disease, and 6 had an ECOG score of 2. At the end of treatment, the overall response rate was 91% (9 CR, 1 PR); 1 pt had PD after Cycle 4. The most frequent (>20%) treatment-emergent adverse events (AEs) were alopecia and nausea (73% each); fatigue (64%); constipation and peripheral sensory neuropathy (55% each); neutropenia and throat irritation (36% each); and chills, diarrhea, headache, and stomatitis (27% each). Grade 3 or 4 AEs occurred in 8 pts and 5 pts had serious AEs, which included febrile neutropenia, bacteremia, nausea, pneumocystis jiroveci pneumonia, pulmonary embolism, and vomiting. Peripheral sensory neuropathy occurred in 6 pts and all were Grade 1 or 2 events; no peripheral motor neuropathy AEs were reported. No AEs were fatal or led to discontinuation. One pt discontinued treatment after Cycle 4 due to disease progression. For the first 51 pts in Part 1, the progression-free survival (PFS) at 18 months for pts with CD30 expression (25 pts) or without detectable CD30 expression (24 pts) by IHC was 79% (95% CI: 57%, 91%) versus 58% (95% CI: 36%, 75%), respectively. Overall survival for pts was 92% (95% CI: 71%, 98%) versus 71% (95% CI: 48%, 85%), respectively. Ten pts had pre-existing peripheral neuropathy (per SMQ) at study entry. Treatment-emergent peripheral neuropathy (per SMQ) was observed in 75% of pts (38/51) who received BV+RCHOP; 55% of these pts (21/38) had resolution of all or some peripheral neuropathy events. Conclusions 1.8 mg/kg BV+RCHP is active as frontline treatment in CD30-expressing, high-intermediate/high risk DLBCL. When combined with RCHP, 1.8 mg/kg BV appears to be well-tolerated. The PFS and OS for pts with CD30-expression who received BV+RCHOP appear promising. The study is currently ongoing in pts with CD30-expressing high-intermediate/high risk DLBCL to assess the safety and activity of 1.8 mg/kg BV+RCHP versus standard RCHOP. Disclosures Halwani: Bristol Myers-Squibb: Research Funding; Kyowa Hakko Kirin: Research Funding; Takeda: Research Funding; Genentech: Research Funding; AbbVie: Consultancy, Other: Travel Expenses, Research Funding; Seattle Genetics: Consultancy, Research Funding; Immune Design: Research Funding; Miragen: Research Funding; Pharmacyclics: Consultancy; Amgen: Research Funding. Yasenchak:Seattle Genetics: Research Funding. Farber:Seattle Genetics: Research Funding. Burke:Pfizer: Consultancy; Janssen: Consultancy; Incyte: Consultancy; TG Therapeutics: Other: Travel Expenses; Millenium: Consultancy. Fayad:Seattle Genetics: Consultancy, Research Funding. Holkova:Seattle Genetics: Research Funding. Knapp:Insys Therapeutics, Inc.: Consultancy, Other: Travel, Accommodations, Expenses; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Other: Travel, Accommodations, Expenses, Research Funding. Kolibaba:Gilead: Consultancy, Research Funding; Celgene: Research Funding; TG Therapeutics: Research Funding; Takeda Pharmaceuticals International Co.: Research Funding; Seattle Genetics: Research Funding; Pharmacyclics: Research Funding; janssen: Research Funding; GSK: Research Funding; Genentech: Research Funding; Acerta: Research Funding. Patel-Donnelly:Seattle Genetics: Research Funding. Yimer:Ariad Pharmaceuticals: Consultancy; Biotheranostics: Consultancy; Bluebird Bio: Equity Ownership; Kite Pharma: Equity Ownership; Clovis Oncology: Equity Ownership; Juno Therpeutics: Equity Ownership; Seattle Genetics: Research Funding. Smith:Celgene: Consultancy, Speakers Bureau; Seattle Genetics: Research Funding. Levy:Janssen: Speakers Bureau; Amgen: Speakers Bureau; Takeda Pharmaceuticals International Co.: Speakers Bureau; Seattle Genetics: Research Funding; Actinium Pharmaceuticals, Inc.: Research Funding. Seetharam:Seattle Genetics: Research Funding. Belada:Seattle Genetics: Research Funding. Brooks:Seattle Genetics: Research Funding. Kingsley:Gilead: Equity Ownership; Pharmacyclics LLC, an AbbVie Company: Equity Ownership. Wagner-Johnston:Seattle Genetics: Research Funding. Ruffner:Forma Therapeutics: Consultancy; Sydnax: Consultancy; Seattle Genetics: Employment, Equity Ownership; Array Biopharma: Employment; Medivation: Employment. Bartlett:Gilead: Consultancy.

Abstract Introduction RCHOP is the standard frontline treatment for patients with DLBCL. However, for patients with high-intermediate or high-risk disease (IPI 3-5), outcomes are suboptimal, with an estimated 3-year PFS of about 55%. In addition to IPI, an additional factor associated with an increased risk include non-GCB cell of origin. Brentuximab vedotin, an ADC targeting CD30, has demonstrated single-agent activity in relapsed/refractory DLBCL patients. Of note, higher ORR and CR, as well as longer duration of PFS, were observed in those patients with CD30 detected on tumor cells by routine IHC. Methods This phase 2 study was designed to evaluate combination therapy using brentuximab vedotin (BV) and standard RCHOP chemotherapy as frontline treatment in patients with high-intermediate/high risk (standard IPI score 3-5 or age-adjusted IPI [aaIPI] score 2-3) DLBCL, regardless of CD30 expression (ClinicalTrials.gov NCT01925612). Patients were randomized to receive either 1.2 mg/kg BV+RCHOP or 1.8 mg/kg BV+RCHOP for up to 6 cycles of treatment. BV was given on Day 1 of every 21-day cycle. Response was assessed per investigator using Cheson 2007. AEs, physical examination findings, and laboratory testing were utilized to characterize safety. Tumor cell CD30 expression was measured by IHC and gene expression analysis; soluble CD30 was measured in plasma. Tumor microenvironment was also evaluated for frequency of immune-infiltrating cells. The primary endpoints for this study were the tolerability of each regimen and the CR rate at the end of treatment (EOT). Key secondary endpoints included progression-free survival (PFS). Additional exploratory endpoints included CD30 expression on tumor specimens (CD30- defined as <1% per IHC) and correlation of CD30 expression and response. Results Twenty-nine patients were treated with 1.2 mg/kg BV+RCHOP and 22 patients were treated with 1.8 mg/kg BV+RCHOP. Over half (63%) were high-intermediate risk (IPI 3, aaIPI 2) and 37% were high risk (IPI 4-5, aaIPI 3). Most had Stage IV disease (71%) and 27% had an ECOG score of 2. AEs in ≥50% of patients included peripheral sensory neuropathy (63%), fatigue (61%), nausea (55%), and diarrhea (53%). Grade 3 or higher events occurred in 76% of patients; the most frequent were neutropenia (33%) and febrile neutropenia (31%). The PET-negative CR rate was 69% overall; CD30+ patients had a CR rate of 76% (19/25) compared with 63% (12/19) in CD30- patients by IHC. Although PFS data are still immature (median follow up of 8 months), the estimated PFS rate at 12 months was 82% (95% CI: 58, 93) in CD30+ patients and 56% (95% CI: 32, 75) in CD30- patients. 60% (3/5) of patients with CD30- ABC-DLBCL progressed versus 27% (3/11) of CD30+ ABC-DLBCL patients. Four patients with EBV+ DLBCL were treated and all achieved CR; 3 EBV+ patients remain in remission after a median follow-up of 12 months. Within the microenvironment, a higher percentage of CD3+ T-cells was observed in patients with CR (23%; range, 4-80%) than in those with PR (14%; range, 10-15%) or PD (11%; range, 5-15%). Of the 32 patients who have not yet progressed, 50% had ≥20% CD3+ cells compared to 18% of patients with PD (2/11). Other factors, including soluble CD30 levels and infiltrating CD68+ cells, were not associated with clinical outcomes. Conclusions Interim results demonstrate that adding BV to RCHOP results in a high rate of CR in this population of IPI 3-5 DLBCL. Patients with CD30-expression in the tumor appear to have a higher CR rate and fewer early progression events than patients with CD30- DLBCL. Furthermore, subsets of patients who have a particularly poor prognosis (CD30+ ABC subtype and EBV+ DLBCL) appeared to have a favorable outcome with BV+RCHOP. Evaluation of the tumor microenvironment showed that higher frequencies of infiltrating CD3+ cells were observed in the CR group, suggesting possible immunologic correlates of response. However, CD30 expression appears to have greater prognostic significance in this study despite the relatively small sample size. These results are intriguing and merit further testing in a randomized trial. Disclosures Yasenchak: Seattle Genetics, Inc.: Research Funding. Off Label Use: Brentuximab vedotin is indicated in the US for treatment of patients with Hodgkin lymphoma after failure of autologous stem cell transplant or after failure of at least two prior multi-agent chemotherapy regimens in patients who are not ASCT candidates and for the treatment of patients with systemic anaplastic large cell lymphoma after failure of at least one prior multi-agent chemotherapy regimen. The drug is being evaluated in this study for use as frontline treatment in patients with high-intermediate/high risk DLBCL in combination with multiagent chemotherapy. . Halwani:Abbvie: Research Funding; Pharmacyclics: Other: Travel expenses, Research Funding; Takeda/Millenium: Research Funding; BMS: Research Funding; Seattle Genetics, Inc.: Other: Travel expenses, Research Funding; Roche/Genentech: Research Funding; Kyowa Hakko Kirin: Research Funding; Amgen: Research Funding. Advani:Seattle Genetics, Inc.: Research Funding; Genetech: Consultancy. Ansell:Bristol-Myers Squibb: Research Funding; Celldex: Research Funding. Budde:Merck: Research Funding; Ikara Inc: Patents & Royalties; Atara Biotherapeutics: Consultancy; Seattle Genetics, Inc.: Research Funding. Burke:Millenium/Takeda: Consultancy; Incyte: Consultancy; TG Therapeutics: Other: Travel expenses; Gilead: Consultancy; Janssen: Consultancy; Seattle Genetics, Inc.: Research Funding. Farber:Seattle Genetics, Inc.: Research Funding. Holkova:Seattle Genetics, Inc.: Research Funding. Kolibaba:GSK: Research Funding; Seattle Genetics, Inc.: Research Funding; Acerta: Research Funding; Celgene: Research Funding; Gilead: Consultancy, Research Funding; Takeda Pharmaceuticals International Co.: Research Funding; Genentech: Research Funding; Pharmacyclics: Research Funding; Janssen: Research Funding; TG Therapeutics: Research Funding. Knapp:Celgene: Research Funding; Heron Pharmaceuticals: Other: Travel expenses, Research Funding; Merck: Research Funding; Seattle Genetics, Inc.: Research Funding; Takeda Pharmaceuticals International Co.: Research Funding; Brystol-Myers Squibb: Research Funding; Genentech: Honoraria, Other: Travel expenses, Research Funding; Pharmacyclics LLC, an AbbVie Company: Research Funding; EMD Serono: Research Funding. Li:Seattle Genetics, Inc.: Employment, Equity Ownership. Manley:Seattle Genetics, Inc.: Employment, Equity Ownership. Patel-Donnelly:Seattle Genetics, Inc.: Research Funding. Seetharam:Seattle Genetics, Inc.: Research Funding. Yimer:Seattle Genetics, Inc.: Research Funding. Bartlett:Gilead: Consultancy, Research Funding; Janssen: Research Funding; Pharmacyclics: Research Funding; Genentech: Research Funding; Pfizer: Research Funding; Novartis: Research Funding; Millennium: Research Funding; Colgene: Research Funding; Medimmune: Research Funding; Kite: Research Funding; Insight: Research Funding; Seattle Genetics: Consultancy, Research Funding; MERC: Research Funding; Dynavax: Research Funding; Idera: Research Funding; Portola: Research Funding; Bristol Meyers Squibb: Research Funding; Infinity: Research Funding; LAM Theapeutics: Research Funding.

Abstract Anti-PD-1 monoclonal antibodies have shown promising results in several hematologic malignancies. As a result, these agents are being tested in a growing number of clinical trials across multiple diseases and settings. Many participants in these trials will at some point become candidates for allogeneic hematopoietic stem cell transplant (HSCT); however, the safety and efficacy of HSCT may differ in patients previously exposed to PD-1 inhibitors given their immunomodulatory mechanism and long tissue half-life. Specifically, residual PD-1 inhibition post-HSCT could enhance allogeneic T-cell responses, which could augment the graft-vs-tumor (GVT) effect but also increase the incidence, severity or manifestations of graft-vs-host disease (GVHD) and other immune complications of HSCT. To report our experience in this setting, we retrospectively analyzed the outcomes of patients who had received a PD-1 inhibitor prior to HSCT. Between 2013 and 2015, 19 patients who previously participated in clinical trials with either pembrolizumab or nivolumab (administered in combination with ipilimumab in 1 patient) were transplanted at Brigham and Women's Hospital/Dana-Farber Cancer Institute. Median age at HSCT was 32 (range 22-67). Histologies included HL (n=11), DLBCL (n=2), FL (n=2), PMBCL (n=2), EATL (n=1), and MCL (n=1). Patients had received a median of 4 (2-8) lines of therapy prior to PD-1 blockade. 79% of patients had received a previous autologous stem cell transplant (21% as part of planned tandem procedure). Patients received a median of 8 (3-20) cycles of a PD-1 inhibitor; 74% had intervening salvage therapy between PD-1 blockade and HSCT, and transplant occurred a median of 130 (range 7-260) days after the last dose of PD-1 inhibitor. At HSCT, 63% of the patients were in CR and 16% had refractory disease. All patients received reduced intensity conditioning (RIC). 5 (26%) received marrow grafts from haploidentical sibling donors; the remaining 14 received peripheral blood stem cells, 5 from a matched sibling, 7 from a matched, 1 from a unidirectional host-versus-graft and 1 from a bidirectional mismatched unrelated donor. 3 cases of veno-occlusive disease (VOD) (16% of patients) were observed, one of them fatal. The 180-day cumulative incidences of grade 2-4 and grade 3-4 acute GVHD were 32% and 11%, respectively, and the 1-year cumulative incidence of chronic GVHD was 30%. There were 4 treatment-related deaths, (1 from VOD, 3 from severe acute GVHD occurring within 14 days of HSCT). In addition, 6 patients developed a febrile syndrome with elevated transaminases (n=3), rash (n= 4), and arthralgias (n=1) shortly after transplant, which required prolonged courses of steroids. Only 3 patients relapsed. After a median follow-up of 10 (3-23) months for survivors, the 1-year overall (OS) and progression-free survivals (PFS) were 78% (95CI, 52-91) and 67% (95CI, 41-84), respectively (Figure). The 1-year cumulative incidences of relapse and non-relapse mortality (NRM) were 11% (95CI, 2-30) and 22% (95CI, 6-43), respectively. In conclusion, HSCT is feasible in patients previously treated with PD-1 inhibitors, with acceptable PFS and OS. Despite the heterogeneous patient population, small sample size, and limited follow-up to date, our results raise the possibility of important differences in the post-HSCT course of those patients. First, the relapse rate compares favorably to that expected for this cohort (1-year expected relapse rate based on Disease Risk Index mix 28%). Although this finding is at best suggestive given the sample size and follow-up time, it could reflect accentuation of GVT by prior PD-1 blockade. We also observed a high rate of severe complications including fatal early acute GVHD and VOD, with a higher NRM than expected in a RIC HSCT population. Furthermore, we noted the frequent occurrence of a steroid-responsive febrile syndrome. These possible effects of prior PD-1 blockade (including GVHD, VOD, febrile syndrome) did not appear related to the time from PD-1 treatment to HSCT, and were not reduced by intervening treatment before HSCT. As we accumulate experience with HSCT after PD-1 blockade, our early results may be relevant when considering the decision to proceed to HSCT and for the choice of transplantation strategies. We are presently expanding this analysis through a multi-center international collaborative study. Updated results will be presented at the meeting. Figure 1. Figure 1. Disclosures Zinzani: Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; J&J: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Perales:Takeda: Honoraria; Astellas: Honoraria; Amgen: Honoraria; Merck: Honoraria; NMDP: Membership on an entity's Board of Directors or advisory committees. Soiffer:Gentium SpA/Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Armand:Sequenta, Inc.: Research Funding; Merck: Consultancy, Research Funding; Infinity: Consultancy, Research Funding; BMS: Research Funding.