Callander, Natalie S.

Abstract Abstract 308 Introduction: The Eastern Cooperative Oncology Group (ECOG) has previously reported the superior 1 and 2 year survival of Ld versus LD as initial therapy in newly diagnosed symptomatic multiple myeloma (MM) (Rajkumar et al Lancet Oncol 2010; 11: 29–37). The 1 year and 2 year OS for Ld vs LD were 96% and 85% vs 88% and 78%, (p < 0.01), respectively. This despite higher ORR in LD vs Ld (79% vs 68%; p = 0.008). The difference in OS was predominantly due to early death in the LD group (5% vs 0.5%; p = 0.003). As a result of this analysis, Ld is now considered the standard of care. However, it should be noted that the majority of these deaths occurred in pts > 65. In this analysis, we evaluated the impact of age on dexamethasone dose intensity and OS. Methods: 445 pts were randomly assigned: 223 to LD and 222 to Ld. Pts were analyzed on an intent-to-treat basis for OS. The pts were analyzed by age in 2 groups: < 65 and > 65 (the age corresponding to transplant eligibility outside the US). The pts > 65 were then further subdivided into >70 and > 75 yrs. Results are expressed as OS probability at 1 and 2 years post randomization. In addition, to eliminate the early death ‘penalty’ in the LD group in the original analysis, a landmark analysis was performed at 4 months. Results: Overall Survival Probability: Intent-to Treat Analysis Overall Survival Probability: 4 month Landmark Analysis Conclusions: As previously reported, OS in the trial at 1 and 2 years was superior with Ld. OS was not superior with LD compared with Ld in any age group despite a higher response rate. This was true even when using a landmark analysis to eliminate the 5% early deaths seen in the first 4 months of treatment. We conclude the following: 1) LD is not definitively superior to Ld in any age group; 2) Given the higher toxicity in the absence of a clear survival benefit with LD, Ld remains the best choice for all ages. This analysis confirms the original opinion that low-dose dexamethasone is the standard of care for all newly diagnosed MM pts, regardless of age. Disclosures: Vesole: Millennium Pharmaceuticals: Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Centorcor-Ortho-Biotech: Speakers Bureau. Off Label Use: Lenalidomide for front-line therapy in multiple myeloma. Abonour:Celgene: Speakers Bureau; Millennium Pharmaceuticals: Speakers Bureau. Callander:Millennium Pharmaceuticals: Research Funding. Fonseca:Amgen: Consultancy; Bristol-Myers Squibb: Consultancy; Celgene: Consultancy, Research Funding; Genzyme: Consultancy; Onyx: Research Funding; Otsuka: Consultancy; Medtronic: Consultancy; Intellikine: Consultancy. Siegel:Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Millennium Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Merck: Membership on an entity's Board of Directors or advisory committees.

Abstract Background: I-131-CLR1404 is a novel radioiodinated therapeutic that exploits the selective uptake and retention of phospholipid ethers (PLEs) by malignant cells. Based on initial preclinical and clinical experience and the exquisite radiosensitivity of MM, I-131-CLR1404 is being examined in RRMM in an open-label, dose escalation Phase 1 trial (NCT02278315) evaluating up to 5 cohorts and a maximum of 37.5 mCi/m2. Methods: The primary objective is to determine safety and tolerability of I-131-CLR1404 with and without dexamethasone (dex) in RRMM. Secondary objectives are to determine the recommended Phase 2 dose (RP2D) and therapeutic activity in RRMM. Eligibility criteria include progressive, relapsed/refractory MM, and at least one previous exposure to proteasome inhibitor (PI) and immunomodulatory (IMiD) drugs. Prior autologous stem cell transplant (ASCT) and external beam radiation therapy are allowed (≤ 20% of total marrow irradiated). There is no limit to the number of prior therapies. I-131-CLR1404 is administered intravenously as a single 30 minute infusion on day 1 with 40 mg dex orally weekly for 12 weeks. Dose-escalation uses a minimally modified, standard 3+3 schema with dose-limiting toxicities (DLTs) assessed through day 85 post-infusion. Adverse events (AEs) are graded by NCI-CTCAE v4.03; responses are assessed by the International Myeloma Working Group Uniform Response Criteria. Results: Ten patients have been enrolled in the study with data presented as of 30 Jun 2016 for 8 patients. Accrual is ongoing in the additional cohorts. Five patients were enrolled to cohort 1 (12.5 mCi/m2 + dex); 4 were evaluable and 1 patient was taken off study for rapid disease progression. Five patients have been enrolled to cohort 2 (18.75 mCi/m2 + dex), with data presented on 3 enrolled prior to data cutoff. The median age was 68.5 (range 55-85) and included 5 males and 3 females. All patients were standard risk (karyotyping) and median bone marrow plasma cell involvement was 25% (range 4-50%). Median number of prior therapies was 4 (range 2-12) (Table 1). Four of 8 patients previously underwent ASCT and 25% were previously treated with radiation therapy. Hematologic AEs (grade 3+) and non-hematologic AEs (grade 2+) potentially related to study drug are shown in Table 1. No difference in the toxicity profile was noted for patients with previous radiation therapy. Two serious adverse events (SAEs) have been reported, both in patients treated with 18.75 mCi/m2 I-131-CLR1404. One patient was hospitalized for a seizure (Day 62), assessed as unrelated to study drug and another patient was hospitalized for a grade 1 upper GI bleed in the setting of grade 4 thrombocytopenia (Day 23). This is believed to be the result of rapidly progressive disease, however relationship to I-131-CLR1404 could not be ruled out. Stable disease was achieved in 100% of evaluable patients (n=7). One subject in cohort 1 demonstrated a > 30% reduction in serum m-protein. Figure 1 provides a summary of percent change in serum free light chain assay (FLC) from baseline. Three patients had a reduction in FLC > 50%, 2 in cohort 1 and 1, to date, in cohort 2. Three patients had a stable FLC response through at least 22 days following treatment and 1 subject was unresponsive with regard to FLC. Median follow-up is 6.8 months (range 1.2-14.2). Patients did not receive subsequent systemic therapy for a median of 3.5 months (range 0.6-4.7). Furthermore, 1 subject in cohort 2 maintains stable disease and has not initiated subsequent treatment. Median progression free survival (PFS) is 3 months and included 4 patients with stable disease at the end of the 85 day study follow-up. In patients with progression after I-131-CLR1404, treatment included daratumumab (n=4), ASCT (n=1), and bortezomib, lenalidomide, and dex (VRD) (n=1). Conclusions: I-131-CLR1404 represents a unique, first in class targeted radiotherapeutic for MM. Preliminary data from this trial show an acceptable and expected safety profile with an efficacy signal in the initial 2 of a potential 5 cohorts. All evaluable patients, despite extensive previous therapy and refractoriness to new therapies, achieved disease stabilization. The study is ongoing to determine the RP2D and long term efficacy. Disclosures Ailawadhi: Pharmacyclics: Consultancy; Novartis: Consultancy; Amgen Inc: Consultancy; Takeda Oncology: Consultancy. Oliver:Cellectar Biosciences: Employment.

Abstract Aim: A phase III trial of lenalidomide plus high (standard) dose dex (RD) versus lenalidomide plus low dose dex (Rd) in newly diagnosed myeloma (MM). Methods: Pts with untreated, symptomatic MM were eligible. Pts in the RD arm (Arm A) received lenalidomide 25 mg/day PO days 1–21 every 28 days plus dex 40 mg days 1–4, 9–12, and 17–20 PO every 28 days; pts in the Rd arm (Arm B) received lenalidomide at the same dose plus dex 40 mg days 1, 8, 15, and 22 PO every 28 days. The primary endpoint was response rate at 4 months, with the null hypothesis being that the response rates in the two 2 arms are equivalent. Planned sample size was 196 eligible pts per arm with one-sided 0.10 Type I and 0.05 Type II error rate. All analysis were performed on an intent to treat basis. An independent DMC recommended release of study results. Results: 445 pts (median age, 65 yrs) were accrued; 223 randomized to RD, 222 to Rd. Median follow-up time is 17 months. Arms were well balanced for age, gender, stage, bone lesions, hemoglobin, beta-2 microglobulin, performance status, bone marrow plasma cells, and M protein levels at baseline. Major grade 3 or higher toxicities, including DVT/PE and infections, were significantly higher in the high dose dex arm (see Table). Overall survival (OS) at the second pre-planned interim analysis was significantly superior with lenalidomide plus low dose dex, P<0.001; one year survival 96% (Rd) versus 87% (RD). The 18 month survival rate is 91% versus 80%, respectively. OS differences in favor of the low dose dex arm were seen in pts <65 (P=0.022; one year rate 97% vs 92%) as well as pts 65 and older (P=0.002; one year rate 94% vs 83%), respectively. Sixty-one patients have died; 42 in the RD arm and 16 in Rd arm. The cause of death has been verified by detailed chart review in 38 patients. Of 29 verified deaths in the RD arm, 13 were due to disease progression, 6 thrombosis/embolism, 3 infection, 3 cardiac ischemia, 1 stroke, and 1 respiratory failure. Of 9 verified deaths in the Rd arm, 5 were due to disease progression, 2 infection, 1 thrombosis/embolism, and 1 cardiac arrest. Response rate data are expected to be available at the time of the meeting. Conclusions: Lenalidomide plus low-dose dexamethasone (Rd) is associated with superior OS compared to lenalidomide plus high-dose dexamethasone (RD) in newly diagnosed MM. The increased mortality in Arm A is due to disease progression (myeloma deaths) as well as increased toxicity. This study has major implications for the use of high-dose dexamethasone in the treatment of newly diagnosed MM. Major Grade 3 or Higher Adverse Events Toxicity Arm A % Arm B % P value Neutropenia 10 19 0.01 DVT/PE 25 9 <0.001 Infections 16 6 <0.001 Any grade 3 or higher non-hematologic 49 32 <0.001 Any grade 4 or higher non-hematologic 20 9 <0.001 Deaths in first 4 months 5 0.5 0.006

Abstract Background: Immunomodulatory agents and proteasome inhibitors have significantly improved outcomes in the management of patients with multiple myeloma (MM). As a consequence, the role of upfront autologous stem cell transplant (ASCT) has become more controversial. The ECOG-ACRIN Cancer Research Group trial E4A03 demonstrated the superiority of lenalidomide (LEN) and low-dose dexamethasone (DEX; Ld) over LEN and high dose DEX (LD) in newly diagnosed MM (Rajkumar SV, Lancet Oncol, 2010). This led to the universal acceptance of Ld as a standard induction regimen. More recently, the FIRST study demonstrated the superiority of Ld as continuous therapy vs Ld given x 18 cycles and melphalan-thalidomide-prednisone x 12 cycles proving continuous Ld should be considered standard of care (Benboubker L, NEJM, 2014). Upon completion of four cycles of therapy, patients enrolled in E4A03 had the option of proceeding to ASCT or continuing on their assigned Ld or LD. A prior post-hoc retrospective landmark analysis (Siegel DS, Abstract, Blood 2010) comparing outcomes of early ASCT vs. no early ASCT showed that in patients <65, 65-70, and >70, the survival with early ASCT at 3 years appeared higher, supporting the role of early consolidative ASCT in newly diagnosed patients. This analysis is the long-term follow-up of the aforementioned study. Methods: A post hoc, retrospective landmark analysis was performed evaluating overall survival (OS) by early ASCT vs. no early ASCT overall and within age subgroups. The Kaplan-Meier method was used to estimate survival distributions and Cox regression for hazard ratio (HR) estimates. The landmark analysis included only patients surviving the first four cycles of therapy. Results: 21% of patients opted for early ASCT (n=90). At baseline (four cycles prior), early ASCT patients were younger (median 57.5y vs 66y), more fit (ECOG PS 0 45% vs 56%) and with less aggressive disease (ISS Stage 3 12% vs 28%). Median treatment duration was 7.6m for no early ASCT patients. The 1, 2, 3, 4, and 5-year survival probability estimates were higher for early ASCT vs. no early ASCT at 99%, 93%, 91%, 85%, and 80% vs. 94%, 84%, 75%, 65%, and 57%. The median OS in the early ASCT vs. no early ASCT was not reached vs. 5.8 years, respectively (Table 1). The survival hazard ratio (HR) for early ASCT was 0.55 [95%CI (0.38-0.80)]. In a further subgroup analysis of patients </= 65, 5-yr survival probability of those who had early ASCT vs. no early ASCT was 79% [95%CI (67-87)] vs. 62% [95%CI (54-69)], respectively. In patients </= 65, median OS in the early ASCT vs. no early ASCT was not reached vs. 7.4 years and the survival HR was 0.74 [95%CI (0.48-1.15)]. For patients >65, 5-yr survival probability of those who had early ASCT vs. no early ASCT was 83% [95%CI (56-94)] vs. 52% [95%CI (45-59)], respectively. In patients >65, median OS in the early ASCT vs. no early ASCT was not reached versus 5.2 years and the survival HR was 0.38 [95%CI (0.17-0.87)]. In all age groups, overall response rate was similar prior to the decision of proceeding with ASCT vs. no early ASCT. In a multivariable model adjusting for baseline prognostic factors, early ASCT retained marginal significance. Conclusions: The landmark analysis demonstrated that patients opting for ASCT after induction Ld/LD had a higher 1, 2, 3, 4, and 5- year survival probability and improvement in median OS regardless of DEX dose density. Results were stronger within the older age cohort and upheld in adjusted models. Limitations include lack of randomization and data on salvage therapy. At a time when lenalidomide and dexamethasone as induction is gaining worldwide acceptance in all age groups, early ASCT is safe and efficacious and should remain a standard of care for newly diagnosed MM even in the era of novel therapies. Table 1. Survival Probabilities (Time from Registration) for all Patients Included in the Landmark Analysis Median 1 year 2-year 3-year 4-year 5-year N Events Median (Yrs)(95% CI) Events Survival Probability(95% CI) Events Survival Probability(95% CI) Events Survival Probability(95% CI) Events Survival Probability(95% CI) Events Survival Probability(95% CI) No Early ASCT All 341 195 5.78(5.11 - 6.59) 22 0.94 (0.90 - 0.96) 53 0.84 (0.80-0.88) 84 0.75 (0.70-0.79) 119 0.65 (0.59-0.69) 144 0.57 (0.51 - 0.62) Early ASCT All 90 34 NR 1 0.99 (0.92 - 1.00) 6 0.93 (0.86 - 0.97) 8 0.91 (0.83 - 0.95) 13 0.85 (0.76 - 0.91) 18 0.80 (0.69 - 0.87) NR = not reached Disclosures Biran: Celgene: Speakers Bureau. Siegel:Celgene Corporation: Consultancy, Speakers Bureau; Amgen: Speakers Bureau; Takeda: Speakers Bureau; Novartis: Speakers Bureau; Merck: Speakers Bureau. Fonseca:Millennium: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Applied Biosciences: Membership on an entity's Board of Directors or advisory committees; Onyx/Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Binding Site: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Bayer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Vesole:Idera Pharmaceuticals: Research Funding; Celgene Corporation: Speakers Bureau. Williams:Celgene: Consultancy, Research Funding. Abonour:Celgene: Research Funding, Speakers Bureau.

Abstract BACKGROUND: The introduction of novel agents and proteasome inhibitors, and advances in high dose therapy administration has made an impact on the survival outcomes for MM patients. However, HRMM still remains a therapeutic challenge with poor prognosis. Even with aggressive approaches such as the Total Therapy protocols, patients with poor genomic risk have a 2-year event-free survival of ~50% (Nair et al, Blood 2010). A randomized Phase I/II trial was designed to evaluate the efficacy of adding immunotherapy into the first line for HRMM patients, comparing lenalidomide, bortezomib and dexamethasone (RVD) with or without addition of elotuzumab (Elo), a humanized monoclonal antibody that binds to SLAMF7/CS1. We are reporting on the Phase I portion of the study. PATIENTS & METHODS: The objective of Phase I was to determine the maximum tolerated dose (MTD) of RVD-Elo. Both low/standard risk MM and HRMM patients were eligible. HRMM was defined by one or more of the following: (1) poor risk genomics by the Arkansas 70-gene model, (2) translocation (14;16), translocation (14;20) and/or deletion (17p) by florescent in-situ hybridization (FISH), (3) primary plasma cell leukemia and (4) serum LDH > 2 times normal levels. The treatment consisted of induction chemotherapy for 8 cycles with RVD-Elo (lenalidomide 25 mg orally days 1-14 of every 21-day cycle; bortezomib 1.3 mg/m2 subcutaneously days 1,4,8,11; dexamethasone 20 mg orally days 1,2,4,5,8,9,11,12; elotuzumab 10 mg/kg intravenously days 1,8,15 cycles 1-2 then days 1,11 cycles 3-8) followed by dose-attenuated RVD-Elo maintenance (lenalidomide 25 mg orally days 1-14; bortezomib 1.0 mg/m2 subcutaneously days 1,8,15; dexamethasone 12 mg orally days 1,8,15; elotuzumab 10 mg/kg intravenously days 1,15) until disease relapse, progression or intolerance. Adverse events (AE) were recorded as per the NCI CTCAEv4.0. RESULTS: Eight newly diagnosed MM patients were enrolled on the Phase I run-in study. Six patients (Figure 1) were evaluable for dose limiting toxicities (DLT) during Cycle 1 as per protocol. The median age of patients was 67 years (range: 56-79 years), with 67% ≥65 years, Hgb was less than 10 g/dL in 50%, creatinine was greater than 2 mg/dL in all patients. ISS stage distribution was 17% (I), 33% (II) and 50% (III). Deletion 13 was observed in 1 patient (17%). The most common AEs (all grades) were fatigue (100%), peripheral sensory neuropathy (83%), edema (83%), lymphopenia (66%) and leukopenia (50%). The most common Grade 3 AEs were peripheral sensory neuropathy (33%), one of which was a DLT, neutropenia (17%) and thrombocytopenia (17%). One Grade 4 lymphopenia was observed. All 6 patients have completed 8 cycles of RVD-Elo induction therapy and 5 patients have completed at least 4 cycles of RVD-Elo maintenance. Overall median days on therapy per cycle were 13 days during induction and 20 days per cycle during maintenance. Dose adjustments were made in 83% of patients for bortezomib, 83% for lenalidomide and 33% for dexamethasone. There were no dose reductions for elotuzumab, although three patients had 1 event each of dose delays/missed dosing attributable to AE/SAE from RVD. Efficacy data will be released at the time that the phase II study of RVD +/- Elo is mature. Discussion/Conclusion: The RVD-Elo is a safe well-tolerated regimen for newly diagnosed MM patients without major additive AE/SAE beyond what is already known about RVD. This is the first report of the only phase I experience combining the triple-drug regimen RVD with the monoclonal antibody Elotuzumab for newly diagnosed MM. Support: NCI grants CA32102, CA38926, CA180821, CA31946, CA21076, CA180799, CA21115, CA180820 and in part by Bristol-Myers Squibb Company Disclosures Usmani: Celgene Corporation: Consultancy, Honoraria, Research Funding; Millennium: Consultancy, Honoraria; Onyx: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy; Array BioPharma: Research Funding; Janssen: Research Funding; Pharmacyclics: Research Funding. Off Label Use: Lenalidomide in newly diagnosed multiple myeloma patients. Ailawadhi:Millennium: Honoraria. Shah:Onyx Pharmaceuticals: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Millennium Pharmaceuticals: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Array: Consultancy, Research Funding. Rosenzweig:Celgene: Speakers Bureau. Durie:IRC J&J: Membership on an entity's Board of Directors or advisory committees; Celgene Corp: Expert Board Committee Other; IRC Onyx: Membership on an entity's Board of Directors or advisory committees; DMC Millennium: Membership on an entity's Board of Directors or advisory committees. Orlowski:Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Onyx Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium: The Takeda Oncology Company: Membership on an entity's Board of Directors or advisory committees, Research Funding; Spectrum Pharmaceuticals: Research Funding; JW Pharmaceutical: Research Funding; Array BioPharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees; Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees.

Abstract Abstract 76 Background: We measured proliferation in MM cells transfected with 13,984 small interfering RNAs in the absence/presence of increasing concentrations of bortezomib (BTZ) and identified 37 non lethal genes as reproducible BTZ sensitizers. The strongest hit was CDK5 a gene expressed at high levels in MM and neural tissues with relatively low expression in other organs suggesting a large therapeutic window. The small molecule CDK5 inhibitor Dinaciclib is a novel, potent, small molecule inhibitor of cyclin dependent kinases (CDK). It selectively inhibits CDK1, CDK 2, CDK 5 and CDK9 with 50% inhibitory concentrations (IC50) in the low nanomolar concentration. Based on these data, we undertook the current trial to evaluate the maximally tolerated dose of Dinaciclib in this patient population as well as assess the efficacy of single agent Dinaciclib in relapsed MM. Patients and Methods: Patients with relapsed MM and measurable disease were enrolled on this phase 1/2 trial provided they had not more than 4 prior lines of therapy for MM, had adequate performance status and organ and hematological function. Patients receiving strong inhibitors/inducers of CYP3A4 were not allowed unless the drugs could be discontinued. The primary objectives were to (i) to determine the MTD of dinaciclib in subjects with relapsed MM (phase 1) and (ii) to evaluate the confirmed response rate with dinaciclib in patients with relapsed MM (phase 2). Dinaciclib was administered on day 1 of a 21-day cycle at doses of 30–50 mg/m2. Dose escalation was done using a 3+3 design and MTD was defined as one dose level below that resulted in >=2 DLTs among 6 patients. Results: Overall, twenty-nine patients were accrued to this study (19 phase I, 10 phase II) from July 2009 to December 2011. Two patients were replaced for study violations and are not included in analysis. The Phase II analysis included the 6 patients treated at the Phase I dose level 50mg/m2 as well as the first 9 patients accrued to the Phase II portion (15 evaluable patients). The median age of the 27 evaluable patients was 66 (range, 49–81); 52% were male. The median duration from diagnosis was 42 months (range, 7–207 months); median number of prior therapies was 4 (range, 1–5). Overall, 11 (41%) patients were considered high-risk by FISH and 56% were ISS stage III at study entry. Patients have received a median of 2 cycles (range: 1–12) and all patients have discontinued treatment for disease progression (18), alternative Treatment (2), adverse Event (4), or other reasons (3). One dose limiting toxicity was seen over all dose levels. One patient at 40 mg/m2 experienced grade 3 constipation possibly related to treatment. The dose level of 50 mg/m2 was determined to be the MTD for the Phase II portion. The overall confirmed response rate was 3 of 27 (11%); including two patients at 40 mg/m2 dose (1 VGPR, 1 PR) and one patient at 50 mg/m2 dose (1 VGPR) with a PR or better. In addition, two patients at 50 mg/mg2 dose have achieved an MR; translating to an overall response rate of 18.5% (5 of 27). Figure 1 shows a waterfall plot of the M protein responses among patients with a measurable M spike. Overall, 21 patients had disease progression and 14 patients have died. Median follow-up for patients still alive is 11.8 months (range: 6.5–19.3). Leukopenia and thrombocytopenia were the most common hematological AEs, and gastrointestinal symptoms, alopecia, and fatigue, were the most common non-hematological AEs seen in the study. Conclusions: The current study demonstrates potential single agent anti-myeloma activity of dinaciclib in a relapsed MM patient population with 2 patients achieving a deep response (VGPR) and many patients obtaining some degree of M protein stabilization or decrease. Ongoing studies are examining dinaciclib in combination with proteasome inhibitors, exploring both weekly and every three-week dosing schedules. Disclosures: Zonder: Millennium Pharmaceuticals, Inc: Consultancy, Research Funding; Celgene: Research Funding.

Abstract Abstract 4055 Introduction: Approximately 15% of patients (pts) with multiple myeloma (MM) exhibit a t(4;14) translocation that results in constitutive activation of the receptor tyrosine kinase (RTK) fibroblast growth factor receptor 3 (FGFR3) in the absence of ligand. This translocation has been strongly linked with a poor prognosis and short survival compared with pts without this translocation. Dovitinib (TKI258) is an RTK inhibitor that has demonstrated in vitro inhibitory activity against FGFR (including FGFR3), vascular endothelial growth factor receptor (VEGFR), and platelet-derived growth factor receptor (PDGFR), with IC50values of approximately 10 nM. Tumor growth inhibition was observed in xenograft tumor models of MM treated with dovitinib. This study was designed to evaluate the efficacy and safety of dovitinib in pts with relapsed or refractory MM that is either t(4;14) positive or negative. Patients and Methods: Adult pts who had received at least 2 prior antimyeloma regimens and who had relapsed or were refractory to their last treatment regimen were enrolled in this multicenter, open-label, 2-stage, phase 2 trial. Pts were evaluated for t(4;14) status at the baseline visit and classified according to the result into either a t(4;14)-positive or a t(4;14)-negative group. Dovitinib was administered at a dose of 500 mg/day on a 5-days-on/2-days-off schedule. Response was characterized as per the International Myeloma Working Group (IMWG) criteria. The primary endpoint was extended overall response rate as defined by the rate of pts with best overall response of complete response, very good partial response, partial response, or minor response. Secondary endpoints included safety, overall response rate, progression-free survival, and pharmacokinetics. After disease progression, pts had the option to continue treatment with the addition of low-dose dexamethasone (40 mg every 7 days) with M-protein levels at the time of progression considered as the new baseline. Results: A total of 43 pts were enrolled in this study; 26 pts were t(4;14) negative, 13 were t(4;14) positive, and 4 pts had unknown/indeterminate t(4;14) status. Median age was 63 years. Most pts (86%; n = 37) had received ≥ 3 prior lines of therapy. No objective responses were observed in either group of pts. Due to the apparent lack of efficacy, the study did not proceed to stage 2. The following observations are based on the preliminary data. In the t(4;14)-negative group, median duration of exposure to the study drug was 4.0 weeks, and 9 of the 26 pts (35%) had stable disease, 13 (50.0%) had progressive disease, and 4 (15%) were not evaluable. Due to slow enrollment and lack of efficacy among the earlier enrolled t(4;14)-positive pts, enrollment for the t(4;14)-positive group was closed prematurely. Among the 13 enrolled t(4;14)-positive pts, median duration of exposure to the study drug was 8.7 weeks. Best responses were stable disease for 8 pts (62%), disease progression for 3 pts (23%), and unknown for 2 pts (15%). Among both groups, the most common adverse events of any grade, regardless of study drug, were nausea (67%), diarrhea (58%), vomiting (51%), fatigue (47%), thrombocytopenia (33%), and anemia (28%). Most of the nonhematologic events were mild. The most common grade 3/4 adverse events were thrombocytopenia (26%) and anemia (23%). The principal reasons for discontinuation of dovitinib monotherapy were disease progression (72%) and adverse events (19%). Six pts continued on the dovitinib plus dexamethasone regimen; 1 pt is ongoing, and 5 pts discontinued due to disease progression (n = 4) and adverse events (n = 1). Conclusion: Dovitinib was found to have no or minimal single-agent activity in relapsed/refractory myeloma irrespective of t(4;14) status. Although the patient numbers are small, the rate of patients with stable disease during study treatment who may have had a clinical benefit was higher in the t(4;14)-positive group, suggesting that this subgroup may be a candidate to explore combination treatment of dovitinib with other agents, such as proteasome inhibitors. Gastrointestinal toxicity, while mostly mild, remains a challenge, and timely monitoring and supportive care during dovitinib treatment may alleviate these symptoms. Dovitinib may be a promising agent for combination therapies to improve prognosis of patients with t(4;14)-positive MM. Disclosures: Scheid: Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Reece:Millennium Pharmaceuticals: Research Funding; Otsuka: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Bristol Myers Squibb: Honoraria, Research Funding; Merck: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding. Spencer:Celgene: Honoraria; Janssen: Honoraria, Speakers Bureau; Novartis: Honoraria. Callander:Millennium Pharmaceuticals: Research Funding. Sonneveld:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Onyx: Honoraria, Research Funding. Kalimi:Novartis Pharmaceuticals: Employment. Cai:Novartis: Employment. Shi:Novartis: Employment, Equity Ownership. Scott:Novartis: Employment. Stewart:Millennium Pharmaceuticals: Consultancy, Honoraria, Research Funding; Onyx: Consultancy; Celgene: Consultancy.

The NCCN Guidelines for Multiple Myeloma provide recommendations for diagnosis, workup, treatment, follow-up, and supportive care for patients with monoclonal gammopathy of renal significance, solitary plasmacytoma, smoldering myeloma, and multiple myeloma. These NCCN Guidelines Insights highlight some of the important updates and changes in the 1.2020 version of the NCCN Guidelines for Multiple Myeloma.