Gonsalves, Wilson I.

Introduction: The bone marrow plasma cell (BMPC) clone burden is typically low in light chain (AL) amyloidosis and some patients do not have a detectable serum monoclonal spike (M-spike). Increased BMPC% and serum free light chain (FLC) are associated with poorer outcomes. However, the outcomes of patients with AL amyloidosis based on the presence or an absence of a measurable serum M-spike before autologous stem cell transplantation (ASCT) has not been explored. Methods: This was a retrospective review of patients who had a diagnosis of AL amyloidosis and received ASCT between March 1996 and September 2017. The serum M-spike was recorded before ASCT and patients were divided according to the presence or absence of a measurable serum M-spike. Progression-free survival (PFS) was defined as time from ASCT to disease progression, relapse or death of any cause. Overall survival (OS) was calculated from time of ASCT to death of any cause. Univariate and multivariate analysis for PFS and OS were done using the following variables: age>65 vs. ≤65 years, Mayo 2012 stage 3/4 vs. 1/2, BMPC ≥ 10% vs. <10%, organs involved >2 vs. ≤2, melphalan conditioning 200mg/m2 vs. 140 mg/m2 ,ASCT year >2010 vs. ≤2010, and presence vs. absence of a measurable serum M-spike. Results: Seven-hundred and sixteen patients were identified and 521 (73%) had a measurable serum M-spike. Patients who had a measurable serum M-spike were more likely to have BMPC≥ 10% than patients without a measurable serum M-spike (46% vs. 34%, P=0.002) and they were more likely to have a difference in FLC ≥18 mg/dl (47% vs. 29%, P=0.0001). Overall, PFS and OS were significantly shorter in patients who had a measurable serum M-spike compared to patients without a measurable serum M-spike (Figure 1 A,B). The shorter survival was irrespective of the administration of induction therapy before ASCT. We also evaluated the difference in survival in patients with Mayo 2012 stage 3/4 based on the presence or absence of a measurable serum M-spike. The PFS and OS were also significantly different in these patients (Figure 1 C,D). Predictors for PFS included Mayo 2012 stage 3/4 vs. 1/2 (hazard ratio (HR): 1.5, P=0.003), BMPC ≥ 10% vs. <10% (HR: 1.4,P=0.004), melphalan conditioning 200mg/m2 vs. 140 mg/m2 (HR:0.6, P=0.001), ASCT year >2010 vs. ≤2010 (HR: 0.8, P=0.03), and the presence vs. absence of a measurable serum M-spike (HR: 1.82, P<0.0001). For OS, Mayo 2012 stage 3/4 vs. 1/2 (HR: 2, P<0.0001), melphalan conditioning 200mg/m2 vs. 140 mg/m2 (HR:0.4, P<0.0001), ASCT year >2010 vs. ≤2010 (HR: 0.6, P=0.002), and the presence vs. absence of a measurable serum M-spike (HR:1.9, P=0.003) were predictive. Conclusion: The presence of a measurable serum M-spike before ASCT is a negative independent predictor for PFS and OS in AL amyloidosis. Figure 1 Disclosures Sidiqi: Amgen: Honoraria; Celgene: Honoraria, Other: Travel grant; Janssen: Honoraria. Dingli:Karyopharm Therapeutics: Research Funding; Apellis: Consultancy; Alexion: Consultancy; Janssen: Consultancy; Bristol Myers Squibb: Research Funding; Rigel: Consultancy; Millenium: Consultancy; Sanofi-Genzyme: Consultancy. Kapoor:Amgen: Research Funding; Celgene: Honoraria; Cellectar: Consultancy; Janssen: Research Funding; Takeda: Honoraria, Research Funding; Sanofi: Consultancy, Research Funding; GlaxoSmithKline: Research Funding. Dispenzieri:Intellia: Research Funding; Alnylam: Research Funding; Pfizer: Research Funding; Takeda: Research Funding; Celgene: Research Funding; Janssen: Research Funding. Kumar:Celgene/BMS: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Janssen Oncology: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; AbbVie: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Takeda: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Tenebio: Other, Research Funding; Genecentrix: Consultancy; MedImmune: Research Funding; Cellectar: Other; Dr. Reddy's Laboratories: Honoraria; Merck: Consultancy, Research Funding; Amgen: Consultancy, Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments, Research Funding; Novartis: Research Funding; Adaptive Biotechnologies: Consultancy; Kite Pharma: Consultancy, Research Funding; Oncopeptides: Consultancy, Other: Independent Review Committee; IRC member; Karyopharm: Consultancy; BMS: Consultancy, Research Funding; Carsgen: Other, Research Funding; Genentech/Roche: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Sanofi: Research Funding. Gertz:Proclara: Other; Abbvie: Other; DAVA oncology: Speakers Bureau; Aurora Bio: Other; Prothena: Other: personal fee; Teva: Speakers Bureau; Physicians Education Resource: Other: personal fee; Annexon: Other: personal fee; Ionis/Akcea: Other: personal fee; Sanofi: Other; Appellis: Other: personal fee; Amgen: Other: personal fee; Janssen: Other: personal fee; Spectrum: Other: personal fee, Research Funding; Medscape: Other: personal fee, Speakers Bureau; Research to Practice: Other; Alnylam: Other: personal fee; Johnson and Johnson: Speakers Bureau; Springer Publishing: Patents & Royalties; Celgene: Other.

Introduction Autologous stem cell transplantation (ASCT) has been used for treating multiple myeloma (MM) for over three decades and is generally reserved for patients younger than 65 years of age. The definition of transplant eligible is ill-defined and different centers have different policies to determine which patients are transplant eligible. Some centers have an age cut-off, others use clinical judgment, and some use various frailty scores (a scoring system based on comorbidities and physical and cognitive assessments) aiming to objectively assess transplant eligibility. There are limited data about outcomes in patients ≥ 75 years. Aim To report on outcomes of ASCT in a cohort of patients with MM aged 75 years or older. Methods Retrospective study of all consecutive MM patients aged ≥ 75 years that underwent ASCT at Mayo Clinic, Rochester, Minnesota. Stem cell transplantation at our center is routinely performed as an outpatient, with patients being hospitalized when deemed clinically necessary upon physician review. Results Between October 2005 and March 2020, 46 patients aged 75 years or older, received an ASCT at Mayo Clinic, Rochester. The median hematopoietic stem cell transplantation specific comorbidity index (HCT-CI) was 0 (range 0-6) with 8 patients having HCT-CI of 5 or 6. Median time from diagnosis to ASCT was 6.45 months (IQR 5.2-10.52) and 54% received reduced intensity conditioning with melphalan 140 mg/m2. All patients except one (that was treated with dexamethasone only) received induction with novel agents (listed in table 1) and 6 patients (13%) received doublet induction. All others received triplet induction. 46% of patients completed the ASCT without requiring hospitalization and 54% (n=25) of patients required hospitalization with a median duration of hospital admission of 9 days (IQR 5-13). Reasons for hospitalization included fever or infection (32%), cardiac arrhythmia (36%) and dehydration (32%). Overall response rate was 100% with a complete response seen in 57% of patients and 16 patients achieving MRD negative sCR. Median overall survival and progression free survival for the cohort were 82 months and 33 months, respectively. One patient died within 100 days of transplant representing a 2% 100-day mortality rate. Univariable cox regression model that evaluated the effect of gender, high risk cytogenetics, hemoglobin, renal function and melphalan dose did not detect any variable that was predictive of OS or PFS (Table 3). Conclusions ASCT is efficacious and can be safely delivered in the outpatient setting in carefully screened patients aged 75 or above. An arbitrary cutoff for age should not be used to exclude patients from ASCT, rather a careful assessment of "physiological age" including performance status and co-morbidities is required by an experienced treating team. Disclosures Kumar: Amgen: Consultancy, Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments, Research Funding; Cellectar: Other; Carsgen: Other, Research Funding; Dr. Reddy's Laboratories: Honoraria; Genentech/Roche: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Sanofi: Research Funding; Kite Pharma: Consultancy, Research Funding; Novartis: Research Funding; Celgene/BMS: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Merck: Consultancy, Research Funding; MedImmune: Research Funding; BMS: Consultancy, Research Funding; Tenebio: Other, Research Funding; Karyopharm: Consultancy; AbbVie: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Janssen Oncology: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Takeda: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Genecentrix: Consultancy; Oncopeptides: Consultancy, Other: Independent Review Committee; IRC member; Adaptive Biotechnologies: Consultancy. Dispenzieri:Pfizer: Research Funding; Janssen: Research Funding; Alnylam: Research Funding; Intellia: Research Funding; Takeda: Research Funding; Celgene: Research Funding. Dingli:Bristol Myers Squibb: Research Funding; Rigel: Consultancy; Janssen: Consultancy; Alexion: Consultancy; Karyopharm Therapeutics: Research Funding; Apellis: Consultancy; Sanofi-Genzyme: Consultancy; Millenium: Consultancy. Kapoor:Cellectar: Consultancy; Takeda: Honoraria, Research Funding; Celgene: Honoraria; Amgen: Research Funding; Sanofi: Consultancy, Research Funding; Janssen: Research Funding; GlaxoSmithKline: Research Funding. Gertz:Prothena: Other: personal fee; Medscape: Other: personal fee, Speakers Bureau; Appellis: Other: personal fee; Alnylam: Other: personal fee; Ionis/Akcea: Other: personal fee; Janssen: Other: personal fee; Research to Practice: Other; Sanofi: Other; Teva: Speakers Bureau; Johnson and Johnson: Speakers Bureau; DAVA oncology: Speakers Bureau; Proclara: Other; Springer Publishing: Patents & Royalties; Celgene: Other; Physicians Education Resource: Other: personal fee; Aurora Bio: Other; Amgen: Other: personal fee; Annexon: Other: personal fee; Spectrum: Other: personal fee, Research Funding; Abbvie: Other.

AbstractThree sets of criteria (International Society of Amyloidosis [ISA], Palladini and Kastritis) were independently developed for staging, progression and response criteria to predict renal survival in patients with AL amyloidosis. We evaluated these criteria using a cohort of 495 newly diagnosed AL amyloidosis patients with renal involvement using time to event competing risk analysis at baseline, 3, 6 and 12 months after treatment. Only Palladini and Kastritis had a staging system and both predicted a higher risk of end stage renal disease (ESRD) in the stage III vs stage I patients but only the Palladini model was predictive for stage II patients. At 3 months, risk of ESRD was significantly higher for Palladini and ISA renal progression (hazard ratio [HR] 2.8 [95% CI: 1.5–5.3, p = .001] and 2.5 [CI: 1.4–4.6, p = .004, respectively]), but renal response was not significantly protective; conversely, the risk of ESRD was not significantly higher for the Kastritis renal progression, but was significantly protective for the Kastritis renal responders (HR 0.38 [95% CI: 0.17–0.84], p = .017). Both progression and response with ISA, Palladini and Kastritis criteria were predictive of ESRD at 6 months and 12 months. While the Palladini staging criteria at baseline, and the ISA and Palladini criteria for progression at 3 months performed better than the Kastritis criteria at baseline and 3 months post‐treatment, the Kastritis criteria performed better for response 3 months after treatment. All three sets of criteria performed well at and after 6 months post‐treatment. These differences are important when choosing endpoints for clinical trials.

AbstractInduction therapy for multiple myeloma with bortezomib (Velcade), lenalidomide (Revlimid), and dexamethasone (d) (VRd) was traditionally administered as bortezomib given twice weekly on a 3 week cycle. A modified schedule of weekly bortezomib has been adopted over time to decrease treatment burden for patients and reduce treatment‐emergent neuropathy. This study evaluates the response rates and outcomes with different schedules of bortezomib in VRd administered for first‐line treatment for patients with newly diagnosed MM (NDMM). We retrospectively analyzed patients treated with upfront VRd from June 30th 2008 to December 31st 2018, for variations of bortezomib administration. Five hundred and fifty‐five (555) NDMM patients met inclusion criteria; median age 63 years and 61% men. Bortezomib was administered twice weekly every 21 days in 43%, once weekly every 21 days in 41% and once weekly every 28 days in 16%. Though peripheral sensory neuropathy was more frequent with twice weekly dosing (P = .002), this group achieved shorter time to best response (P = .01). Weekly every 21‐day treatment saw higher VGPR or better rates (P = .02). However, with median follow up time of 37 months (IQR 22–56), we found no difference in PFS or OS among the groups. While small differences in response rates were found among the varying administration schedules of bortezomib administration, there was no significant effect on PFS or OS. Given that VRd remains a first line standard of care option for newly diagnosed MM, in the absence of a large trial comparing bortezomib dosing schedule modifications, these results are helpful in supporting current practices of once weekly administration.

AbstractIntroductionLittle is known on continued response following completion of therapy in light chain (AL) amyloidosis.MethodsWe studied 373 AL amyloidosis patients who achieved complete response (CR) or very good partial response (VGPR) to first‐line therapy.ResultsBy end of therapy (EOT), 46% of patients achieved a CR and 54% a VGPR. With no further therapy, 17.5% of patients were upstaged from VGPR to CR (delayed CR), with a median of 9 months. Compared with CR and VGPR at EOT, patients with a delayed CR were characterized by higher proportion of t(11;14) and lower rate of trisomies. Autologous stem cell transplant was more frequent in the delayed CR group. Patients with a delayed CR were characterized by minimal residual disease negativity and organ response rates similar to patients with CR at EOT and higher than patients achieving VGPR at EOT. Patients with a delayed CR had a longer PFS/OS compared to patients with CR or VGPR by EOT (median PFS 149 vs 92 vs 52 months, P < .001; 10‐year OS 87% vs 71% vs 56%, P < .001).ConclusionsThis study characterizes delayed CR in AL amyloidosis, highlights its prognostic impact which is at least similar to those who achieved CR at EOT, and underlines another aspect of response monitoring.

SummaryMeasurable residual disease (MRD) assessment by marrow‐based next‐generation flow cytometry (NGF) following autologous stem cell transplantation (ASCT) may lead to false‐negative results due to patchy marrow involvement and extramedullary disease in patients with multiple myeloma. We assessed the value of simultaneous MRD evaluation with NGF and serum matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry (MASS‐FIX). Of all 61 complete responders who were NGF‐negative for MRD, around day‐100 post ASCT, 59% were MASS‐FIX‐positive. At median follow‐up of 26 months, 69% of MASS‐FIX(+)/NGF(−) patients were alive and progression‐free versus 96% of MASS‐FIX(‐)/NGF(−) patients, P = 0·02. MASS‐FIX, a simple peripheral blood‐based assay complements marrow‐based NGF to accurately prognosticate patients with myeloma.

Key Points Systemic immune microenvironment signatures in CMML indicate an altered T- and natural killer cell balance. CMML bone marrow dendritic cell aggregates associate with disease progression and systemic regulatory T-cell phenotypic switch.

Introduction: In general, the use of an immunomodulator (IMiD), proteasome inhibitors (PI) and dexamethasone (dex) for the treatment of MM is associated with better outcomes. The management of elderly patients with multiple myeloma (MM) is challenging due to difficulty in managing their co-morbidities and inability to tolerate treatment side effects. We evaluated therapies and outcomes of elderly patients with newly diagnosed MM. Methods: This is a retrospective study of patients with MM who were &gt;75 years old treated at the Mayo Clinic, Rochester from January 2004 to January 2018. We included patients who were treated on clinical trials as well as off-trials. Patients were classified as receiving treatment with IMiD+PI+dex, alkylator+PI+steroid, IMiD+dex, PI+dex, alkylator+IMid+steroid, and other (alkylator with steroid or steroid only). Treatment response was documented as well as the progression-free (PFS), defined as the time from therapy initiation to disease relapse or death from any cause and overall survival (OS), defined as the time from start of treatment to death from any cause. A multivariate analysis for factors affecting OS was done including the following variables: being on a triplet combination (alkylator+PI+steroid, IMid+PI+dex, or alkylator +IMiD+steroid), revised international staging system (R-ISS)(stage 3 vs. 1-2), bone marrow plasma cell percentage (BMPC%)(&gt;60% vs. ≤60%), and receiving treatment during or after 2010 vs. before 2010. Analysis was done for patients treated off-trials, as well as, including trial patients. Results: We identified 394 patients with MM who were &gt;75 years old and 246 (62%) were male. For non-trial patients (n=350), IMiD+dex (32%) was the most commonly used regimen followed by alkylator with steroid or steroid only (20%), alkylator+PI+steroid (18%), and IMid+PI+dex (13%). The remaining patients were treated with PI+dex (12%) and alkylator +IMiD+steroid (5%). Forty-four patients (11%) were treated in clinical trials with alkylator+IMid+steroid (47%), IMiD+dex (25%), IMiD+PI+dex (14%), and alkylator+PI+steroid (14%). The median follow up was 45.9 months with an interquartile range of 28.2 to 75.6 months. Overall, achieving very good partial response or complete response was more likely in patients who were treated with an IMid+PI+dex (58%) or alkylator+PI+steroid (47%), compared to in other therapies (5-30%)(P&lt;0.0001). The PFS and OS for non-trial patients are displayed in Figure 1 (A,B) and for all, including trial patients in (C,D). Overall, the median OS was significantly longer in patients who were treated with a triplet in non-trial as well as all patients. In a multivariate for OS including non-trial patients, predictors for better OS included receiving a triplet (HR: 0.63, P=0.02) and not having an R-ISS stage 3 (HR: 0.39, P=0.001). This was also found when including trial patients (using a triplet, HR: 0.65, P=0.01 and not having an R-ISS stage 3, HR: 0.35, P=0.0002). Conclusion: In MM patients &gt;75 years old, being able to receive triplet therapy is associated with better survival. This study provides better understanding of the natural history of MM outside of trials in the elderly age group. Disclosures Dispenzieri: Celgene: Research Funding; Alnylam: Research Funding; Pfizer: Research Funding; Intellia: Research Funding; Takeda: Research Funding; Janssen: Research Funding. Dingli:Bristol Myers Squibb: Research Funding; Alexion: Consultancy; Millenium: Consultancy; Rigel: Consultancy; Sanofi-Genzyme: Consultancy; Apellis: Consultancy; Janssen: Consultancy; Karyopharm Therapeutics: Research Funding. Kapoor:GlaxoSmithKline: Research Funding; Amgen: Research Funding; Takeda: Honoraria, Research Funding; Sanofi: Consultancy, Research Funding; Janssen: Research Funding; Cellectar: Consultancy; Celgene: Honoraria. Gertz:Spectrum: Other: personal fee, Research Funding; Janssen: Other: personal fee; Prothena: Other: personal fee; Alnylam: Other: personal fee; Ionis/Akcea: Other: personal fee; Springer Publishing: Patents & Royalties; Proclara: Other; DAVA oncology: Speakers Bureau; Johnson and Johnson: Speakers Bureau; Teva: Speakers Bureau; Sanofi: Other; Research to Practice: Other; Celgene: Other; Abbvie: Other; Aurora Bio: Other; Physicians Education Resource: Other: personal fee; Medscape: Other: personal fee, Speakers Bureau; Amgen: Other: personal fee; Appellis: Other: personal fee; Annexon: Other: personal fee. Kumar:Carsgen: Other, Research Funding; Tenebio: Other, Research Funding; BMS: Consultancy, Research Funding; Karyopharm: Consultancy; MedImmune: Research Funding; Sanofi: Research Funding; Novartis: Research Funding; Kite Pharma: Consultancy, Research Funding; Oncopeptides: Consultancy, Other: Independent Review Committee; IRC member; Genentech/Roche: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Celgene/BMS: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Adaptive Biotechnologies: Consultancy; Merck: Consultancy, Research Funding; Amgen: Consultancy, Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments, Research Funding; Janssen Oncology: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Takeda: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; AbbVie: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Dr. Reddy's Laboratories: Honoraria; Cellectar: Other; Genecentrix: Consultancy.

Background: Oncolytic virotherapy is a novel immunomodulatory therapeutic approach for relapsed refractory hematologic malignancies. The Indiana strain of Vesicular Stomatitis Virus (VSV) has been engineered to encode interferon beta (IFNβ) and sodium iodine symporter (NIS) to produce VSV-IFNβ-NIS. The virally encoded IFNβ serves as an index of viral proliferation and enhances host anti-tumor immunity. The NIS is inserted as a reporter gene into the viral genome to enable noninvasive monitoring of viral spread using PET/CT imaging. Here we present results of Arm A (patients with low tumor burden) of the Phase I clinical trial (NCT03017820) of intravenous administration of VSV-IFNβ-NIS for patients (pts) with relapsed refractory hematological malignancies: MM, AML, and TCL. Methods: This was a classical 3+3 phase I trial, starting at 5x10^9 TCID50 (50% tissue culture infectious dose) level 1 through 1.7x10^11 TCID50 dose level 4 given as a single IV dose. The primary objective was determining the maximum tolerated dose of VSV-IFNβ-NIS alone; secondary objectives include estimating the safety profile and preliminary efficacy. Correlative objectives include monitoring the pharmacodynamics of viral replication through SPECT/CT imaging with NIS gene, viremia, virus shedding and changes in the immune profile of peripheral blood leukocytes. Adverse events (AEs) are reported based on CTCAE v4; cytokine release syndrome (CRS) grading was based on Lee (Blood 2014; 124(2):188-195) criteria. Results: From April 2017, 12 pts have received IV VSV-IFNβ-NIS in Arm A: MM (7), TCL(4) and AML(1); 3 pts were treated at each dose level (DL) 1 to 4. At DL1, there were five grade 3 hematologic AEs (leukopenia [1], neutropenia [1], lymphopenia [3]) and no grade 3+ non-hematologic AEs. At DL2, three grade 3 hematologic AEs (anemia [2], lymphopenia [1]), four grade 4 hematologic AEs (neutropenia [1], leukopenia [1], lymphopenia [1] and thrombocytopenia [1]). There was 1 event of grade 2 CRS at DL2, two grade 3 non-hematologic AEs (nausea [1], dehydration [1]). At DL3, there was one grade 4 hematologic AE (neutropenia [1]), three grade 3 hematologic AEs (lymphopenia [2], leukopenia [1]), and one grade 3 non-hematologic AE (vasovagal reaction [1]). One grade 2 and grade 1 CRS by Lee criteria were observed. At DL4, there were three grade 3 hematologic AEs (lymphopenia [1], neutropenia [1], thrombocytopenia [1]), and three grade 3 non-hematologic AEs (AST increase [1], skin infection [1], soft tissue infection [1])and two grade 2 CRS. There were no dose limiting toxicities. There was one partial response (DL2) and one complete response (DL4); 3 pts had stable disease, 7 pts progressed. The MM pts receiving VSV-IFNβ-NIS at DL4 had stable disease. Six of the 7 MM pts demonstrated transient reduction in serum level of involved free light chain (LC) after VSV-IFNβ-NIS infusion, with median 20.4% reduction of the involved LC within 48 hrs. Viremia was detectable in all pts at the end of infusion, to varying levels at 30 mins, 1, 2, 4, 24, 48h or 72 hrs post infusion. No persistent viremia was observed. No infectious virus was recovered in buccal swabs or urine and neutralizing anti-VSV antibodies were present by day 29. The IFN levels were detectable within 30 minutes of infusion and peaked between 4 and 48 hrs. The pts with a diagnosis of TCL mounted higher hIFNβ levels within 48 hrs. Remarkably, the TCL pt with CR (DL4) mounted a peak hIFNβ response of 18213.3pg/ml at 48 hrs post infusion, approximately 15-fold higher than any other pt enrolled in the study; and highest neutralizing antibody titer (1:40960). Conclusion: VSV-IFNβ-NIS can be safely administered by intravenous infusion in pts with hematological malignancies, up to a dose level of 1.7 x 1011 TCID50, without dose limiting toxicities and no CRS higher than grade 2. In this small phase 1 study, pts with T-cell lymphoma demonstrated the strongest signal of response, with one confirmed partial response at DL2 and one complete response at DL4. IFNβ is an early biomarker of tumor susceptibility; the magnitude of IFNβ elevation appears to correlate with treatment response. There were no confirmed responses in pts with MM, but the 20.4% transient reduction in LC suggests that combination strategies with VSV-IFNβ-NIS may result in deeper and sustained responses in MM. Future trials investigating combination strategies with immune modulatory drugs are being planned. Disclosures Peng: Imanis: Other: Equity Ownership. Witzig:Karyopharm Therapeutics: Research Funding; Immune Design: Research Funding; Spectrum: Consultancy; Incyte: Consultancy; Acerta: Research Funding; MorphSys: Consultancy; AbbVie: Consultancy; Celgene: Consultancy, Research Funding. Dispenzieri:Intellia: Research Funding; Pfizer: Research Funding; Takeda: Research Funding; Alnylam: Research Funding; Janssen: Research Funding; Celgene: Research Funding. Gertz:Celgene: Consultancy; Annexon: Consultancy; Sanofi: Consultancy; Appellis: Consultancy; Amgen: Consultancy; Medscape: Consultancy, Speakers Bureau; Physicians Education Resource: Consultancy; Data Safety Monitoring board from Abbvie: Membership on an entity's Board of Directors or advisory committees; NCI SPORE MM: Research Funding; Johnson and Johnson: Speakers Bureau; Springer Publishing: Patents & Royalties; Amyloidosis Foundation: Research Funding; Advisory Board for Proclara: Membership on an entity's Board of Directors or advisory committees; Alnylam: Consultancy; Ionis/Akcea: Consultancy; Spectrum: Consultancy, Research Funding; Prothena: Consultancy; DAVA oncology: Speakers Bureau; i3Health: Consultancy; Advisory Board for Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy; International Waldenstrom Foundation: Research Funding. Dingli:Rigel: Consultancy; Bristol Myers Squibb: Research Funding; Janssen: Consultancy; Alexion: Consultancy; Apellis: Consultancy; Karyopharm Therapeutics: Research Funding; Millenium: Consultancy; Sanofi-Genzyme: Consultancy. Kapoor:Cellectar: Consultancy; Celgene: Honoraria; Janssen: Research Funding; Sanofi: Consultancy, Research Funding; Amgen: Research Funding; Takeda: Honoraria, Research Funding; GlaxoSmithKline: Research Funding. Lin:Janssen: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; Legend BioTech: Consultancy; Juno: Consultancy; Bluebird Bio: Consultancy, Research Funding; Novartis: Consultancy; Celgene: Consultancy, Research Funding; Merck: Research Funding; Takeda: Research Funding; Gamida Cells: Consultancy; Sorrento: Consultancy, Membership on an entity's Board of Directors or advisory committees; Vineti: Consultancy. Kumar:Janssen Oncology: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Cellectar: Other; Carsgen: Other, Research Funding; AbbVie: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Merck: Consultancy, Research Funding; Oncopeptides: Consultancy, Other: Independent Review Committee; IRC member; Sanofi: Research Funding; Dr. Reddy's Laboratories: Honoraria; Adaptive Biotechnologies: Consultancy; Genentech/Roche: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Kite Pharma: Consultancy, Research Funding; Novartis: Research Funding; Celgene/BMS: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; MedImmune: Research Funding; Amgen: Consultancy, Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments, Research Funding; Karyopharm: Consultancy; Takeda: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; BMS: Consultancy, Research Funding; Genecentrix: Consultancy; Tenebio: Other, Research Funding. Russell:Imanis: Other: Equity Ownership. OffLabel Disclosure: This describes of administration of Vesicular Stomatitis Virus Genetically Engineered to Express NIS and human interferon, in Patients with Relapsed or Refractory Hematologic malignacies