ALBERT

Description: Key PointsThe CHAMPION-1 study is the first clinical trial to investigate carfilzomib on a once-weekly dosing schedule with dexamethasone. Once-weekly carfilzomib (30-minute infusion; 20 and 70 mg/m2) with dexamethasone is feasible and effective in relapsed/refractory MM.

Description: Background: Preclinical studies indicate that lenalidomide (LEN) and POM are not cross-resistant (Ocio et al Leukemia, 2015) and that POM remains active in LEN-resistant myeloma cells (Lopez-Girona et al Leukemia, 2012). Likewise, POM + LoDEX showed comparable efficacy in patients (pts) refractory to LEN administered as last prior Tx vs the full population in subanalyses of the clinical trials MM-002 and MM-003 (San Miguel et al Lancet Oncol, 2013; Richardson et al Blood, 2014). To confirm these observations, we initiated a single-arm, phase 2 trial evaluating POM + LoDEX immediately following second-line LEN-based Tx in advanced RRMM (MM-014; NCT01946477). Methods: Eligible pts (aged ≥ 18 yrs) had received 2 prior lines of Tx, with ≥ 2 cycles of LEN-based Tx in the second line. Pts must have had documented progressive disease (PD) during or after their last antimyeloma Tx and Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2. POM was administered 4 mg/day on days 1-21 of a 28-day cycle with LoDEX 40 mg/day (20 mg/day for pts aged 〉 75 yrs) on days 1, 8, 15, and 22 until PD or discontinuation for any reason. Pts received mandatory thromboprophylaxis. The primary end point was overall response rate by modified International Myeloma Working Group criteria (including minor response). Secondary end points included progression-free survival, overall survival, time to progression, safety, and duration of response. Exploratory end points were included to identify molecular, immune, and cellular biomarkers that might inform POM + LoDEX response, resistance, or mechanism of action. Results: As of March 20, 2015, 27 of the 85 planned pts were enrolled and received POM + LoDEX. Twelve pts remain on Tx, whereas 15 have discontinued, due to PD (n = 7) and withdrawal (n = 5), but not adverse events (n = 0). Males comprised 59% of pts; 85% were white and the median age was 69 yrs (range, 44-85 yrs), with 67% of pts aged ≥ 65 yrs. The median time since diagnosis was 3.9 yrs (range, 1.3-13.3 yrs), and 59% of pts received prior stem cell transplant. Most pts (81%) were refractory to the most recent prior LEN-containing Tx, and the median duration of the most recent prior LEN Tx was 8.3 mos (range, 0.3-56.3 mos). The 19% of pts who were not refractory to the most recent prior LEN-containing Tx remain on Tx. Pts predominantly had ECOG performance status 0 or 1 (30% and 63%, respectively) vs 2 (7%). Of the 19 pts with International Staging System assessment reported, most were stage I (n = 7) or II (n = 11) vs III (n = 1). Efficacy and safety data will be presented. Conclusions: The MM-014 study is assessing the efficacy and safety of POM + LoDEX in pts with RRMM who have received second-line LEN-based Tx. MM-014 is designed to confirm and expand the results from MM-002 and MM-003 with translational data. Clonality and biomarkers, including Aiolos, Ikaros, IRF-4, and c-Myc, will be evaluated to determine association with POM + LoDEX synergy, high-risk MM-associated genetic aberrations, clonal evolution, and minimal residual disease. Disclosures Siegel: Celgene Corporation: Speakers Bureau; Amgen: Speakers Bureau; Takeda: Speakers Bureau; Merck: Speakers Bureau; Novartis: Speakers Bureau. Schiller:Celgene Corporation: Research Funding. Song:Celgene Canada: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Stockerl-Goldstein:Celgene Corporation: Speakers Bureau; Onyx: Speakers Bureau. Kaya:Novartis: Honoraria, Speakers Bureau; Millennium: Honoraria, Speakers Bureau; Celgene: Honoraria, Speakers Bureau; Onyx: Honoraria, Speakers Bureau; Amgen: Honoraria, Speakers Bureau. Sebag:Amgen: Honoraria; Celgene: Honoraria; Novartis: Honoraria; Janssen: Honoraria. Reu:Takeda/Millennium: Research Funding; Novartis: Research Funding; Celgene: Research Funding. Mouro:Celgene Corporation: Employment, Equity Ownership. Sturniolo:Celgene Corporation: Employment. Srinivasan:Celgene Corporation: Employment, Equity Ownership. Thakurta:Celgene Corporation: Employment, Equity Ownership. Nagarwala:Celgene Corporation: Employment, Equity Ownership. Bahlis:Johnson & Johnson: Speakers Bureau; Johnson & Johnson: Consultancy; Amgen: Consultancy; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Johnson & Johnson: Research Funding.

Description: Background: Pomalidomide (POM) in combination with low-dose dexamethasone (LoDEX) is approved for the treatment (Tx) of patients (pts) with multiple myeloma (MM) who have had ≥ 2 prior lines of therapy, including lenalidomide (LEN) and a proteasome inhibitor. Although LEN and POM are both IMiD® immunomodulatory agents, preclinical studies have shown that LEN is not cross-resistant with POM (Ocio et al, Leukemia, 2015) and that LEN-resistant myeloma cells remain sensitive to POM (Lopez-Girona et al, Leukemia, 2012). Furthermore, sub-analyses of the MM-002 and MM-003 trials demonstrated that POM + LoDEX had comparable efficacy in pts refractory to their last prior Tx with LEN as in the overall pt population (San Miguel et al, Lancet Oncol, 2013; Richardson et al, Blood, 2014). Here, we present an updated analysis of MM-014, a single-arm, phase 2 trial of POM + LoDEX in pts with MM relapsed or refractory to LEN-based second-line therapy. Methods: Pts were ≥ 18 years old with a documented diagnosis of MM, measurable disease, 2 prior lines of Tx, and progressive disease after ≥ 2 cycles of second-line Tx with a LEN-based therapy. The Tx regimen was POM 4 mg/day on days 1-21 and LoDEX 40 mg/day (20 mg/day for pts 〉 75 years old) on days 1, 8, 15, and 22 of a 28-day cycle; thromboprophylaxis was mandatory. Responses were assessed using modified International Myeloma Working Group criteria. The primary endpoint was overall response rate (ORR; ≥ partial response [PR]). Secondary endpoints included time to response (TTR), duration of response (DOR), time to progression (TTP), progression-free survival (PFS), and overall survival (OS). Secondary primary malignancies (SPMs) were monitored and recorded as serious AEs regardless of relationship to Tx. Exploratory endpoints included measures to identify potential molecular, immune, and cellular biomarkers for POM + LoDEX response, resistance, or mechanism of action. Results: Of 51 enrolled pts (N = 85 planned), 16 (31.4%) remain on Tx, and 35 (68.6%) discontinued from Tx (n = 20 due to PD, n = 7 due to withdrawal by pt, and n = 2 each due to adverse event [AE], death, lack of efficacy, and other reasons). The median age was 68.0 years, and most pts (92.2%) had an Eastern Cooperative Oncology Group performance status of ≤ 1; 34 pts (66.7%) were refractory to their last Tx with LEN, and 37 (72.5%), 2 (3.9%), and 1 (2.0%) pts had prior Tx with bortezomib, carfilzomib, or ixazomib, respectively. A total of 33 pts (64.7%) had prior stem cell transplant. The median duration of the most recent prior LEN-containing Tx was 24.6 months, and the median study follow-up time was 11.4 months. The ORR was 31.4%, including 3.9% (n = 2) with complete response, 5.9% (n = 3) with very good PR, and 21.6% (n = 11) with PR. The clinical benefit rate (≥ minimal response) was 41.2%. Of the 16 pts who achieved ≥ PR, 12 (75.0%) have an ongoing response; median TTR in these pts was 1.9 months. The median DOR based on Kaplan-Meier estimates was not reached. The 1-year PFS, OS, and TTP rates were 60.2%, 87.4%, and 64.6%, respectively. Common (≥ 5%) grade 3/4 AEs included anemia (23.5%), neutropenia (13.7%), thrombocytopenia (9.8%), fatigue (7.8%), and infections (19.6%; including pneumonia [7.8%]). AEs of special interest (any grade) included pulmonary embolism (3.9%), deep vein thrombosis (2.0%), and peripheral sensory neuropathy (3.9%); no SPMs were observed. The immune subset analysis showed a significantly elevated proportion of CD3+/CD8+ T cells after Tx (cycle 3, 5, day 1) compared with baseline (37.6% vs 30.5% of total lymphocytes; P 〈 .01). A similar trend toward elevated proportions of CD3+ T cells (73.7% vs 66.6%) was observed; however, the difference was not significant. There was no significant change in CD3+/CD4+ T cells (35.9% vs 35.5%). Conclusions: This updated analysis of the MM-014 trial demonstrates the safety and efficacy of POM + LoDEX in pts who were relapsed or refractory to their last prior Tx with LEN. Results suggest that POM + LoDEX can be used immediately following LEN-based therapy to treat pts with relapsed/refractory MM. The study has been amended to include a cohort of pts treated with POM + LoDEX + daratumumab. Investigations of additional biomarkers, high-risk genetic aberrations, clonal evolution, and minimal residual disease in MM-014 are currently underway. Disclosures Siegel: Novartis: Honoraria, Speakers Bureau; Celgene: Honoraria, Speakers Bureau; Amgen: Honoraria, Speakers Bureau; BMS: Honoraria, Speakers Bureau; Takeda: Honoraria, Speakers Bureau; Merck: Honoraria. Schiller:Incyte Corporation: Research Funding. Song:Otsuka: Honoraria; Celgene: Honoraria, Research Funding; Janssen: Honoraria. Kaya:Celgene, Amgen, Takeda: Honoraria. Sebag:Janssen: Honoraria; Celgene: Honoraria; Novartis: Honoraria. Reu:Celgene, Novartis and Takeda: Research Funding; Signal Genetics, Inc.: Consultancy. Mouro:Celgene: Employment, Equity Ownership. Chung:Celgene: Employment. Srinivasan:Celgene: Employment; Individual Patent: Patents & Royalties: US7,495,673B1 Used for MM-Connect Treatment Patterns Abstract.. Qian:Celgene: Employment. Rizvi:Celgene: Employment, Equity Ownership. Thakurta:Celgene: Employment, Equity Ownership. Bahlis:Celgene: Consultancy, Honoraria, Other: Travel Expenses, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Other: Travel Expenses, Research Funding, Speakers Bureau; BMS: Honoraria; Onyx: Consultancy, Honoraria.

Description: Background: Warm antibody autoimmune hemolytic anemia (wAIHA) is a rare and often serious disease characterized by antibody-mediated destruction of red blood cells (RBCs). Activation of Fc receptors on macrophages in turn activates spleen tyrosine kinase (SYK), which triggers a signaling cascade leading to phagocytosis of the antibody-bearing cells. Fostamatinib, a SYK inhibitor, markedly improved Hgb levels in 9 of 17 (53%) patients with wAIHA during a phase 2, open-label, multicenter study. This abstract reports the results of ongoing fostamatinib treatment as of 2 July 2018 in patients who completed the 24-week treatment period and rolled over into the extension period of the study. Methods: Eligible adult patients had primary or secondary wAIHA and had failed more than one prior treatment for wAIHA. Patients had to have hemoglobin (Hgb) 10 g/dL with an increase of ≥2 g/dL from baseline by Week 24 without rescue therapy or RBC transfusion) OR have shown a beneficial trend during the 24-week treatment period and [2] tolerated study drug. Fostamatinib 150mg BID (or the dose taken at the end of the 24-week treatment period, if a dose reduction had occurred) was taken orally with no food restriction, and patients were seen every 6 weeks during the extension period. Results: Six patients have entered the extension period including 5 who had met the primary efficacy endpoint and 1 who showed a beneficial trend at Week 24 (and had a response at Week 30). One patient had lymphoproliferative disease. Prior AIHA treatment included splenectomy (1), steroids (6), and rituximab (2). The median duration of disease was 1.9 years (range 0.4-15.7). The mean age was 58.7 years (range 30-86), 5 were female, all were white, and 4 were Hispanic or Latino. At baseline the median Hgb was 9.1 g/dL (range: 8.6-9.5); the median lactate dehydrogenase was 273 U/L (range 233-781); the median reticulocyte count was 252.2 x109/L (range 7.8-350.0); and the median haptoglobin was 7.0 mg/dL (range 7.0-9.0). The direct antiglobulin test was positive for IgG in 5 patients at screening. Median Hgb levels increased over the course of the study. See figure. Four of 6 patients had an ongoing response as of the data cutoff date, and none has had rescue therapy or an RBC transfusion. All 6 patients had ≥1 adverse event (AE) during the study, including noninfectious diarrhea in 1 (treatment-related), hepatic disorders in 3 (treatment-related in 2; treatment interrupted in 1), and hypertension in 1 (not related). One patient had a serious AE (inappropriate antidiuretic hormone secretion), which was not related to fostamatinib. To date, no new safety signals have been detected. Summary/Conclusion: Patients with wAIHA continued to display markedly improved Hgb levels during the extension period of the study. Side effects were manageable and consistent with those previously reported with fostamatinib in other conditions. Figure. Figure. Disclosures Kuter: ONO: Consultancy; Protalex: Research Funding; Rigel: Consultancy, Research Funding; BMS: Research Funding; Pfizer: Consultancy; Novartis: Consultancy; Amgen Inc.: Consultancy; Principia: Research Funding; Bioverativ: Consultancy, Research Funding; Argenx: Consultancy; Syntimmune: Consultancy; Dova Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees. Arnold:Amgen: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; UCB: Consultancy; UCB: Consultancy; Bristol Myers Squibb: Research Funding; Novartis: Consultancy, Research Funding; Bristol Myers Squibb: Research Funding. Boxer:Incyte: Speakers Bureau; Rigel: Speakers Bureau; AbbVie: Speakers Bureau. Broome:Bioverativ: Honoraria; Alexion: Honoraria. Field:Prolong: Research Funding; Ironwood: Consultancy, Research Funding; Incyte: Research Funding. Lowe:Rigel: Consultancy. Tong:Rigel: Employment, Equity Ownership. Zayed:Rigel: Employment, Equity Ownership. Duliege:Rigel: Employment, Equity Ownership.

Description: Introduction: Carfilzomib is an irreversible second-generation proteasome inhibitor that is currently approved for the treatment of relapsed or refractory multiple myeloma (MM). The primary objective of the CHAMPION-2 study was to determine the maximum tolerated dose (MTD) of carfilzomib when used with cyclophosphamide and dexamethasone (KCyd) for newly diagnosed MM, and secondary objectives were to evaluate the overall response rate (ORR), time to response (TTR), and safety of KCyd. Methods: This was a multicenter, open-label, single-arm, phase 1b study that enrolled patients 18 years or older with newly diagnosed symptomatic MM. Patients deferring transplant and transplant-ineligible patients were allowed. Treatment was given in 28-day cycles and continued for 8 cycles, or until unacceptable toxicity, withdrawal of consent, or progressive disease. A traditional 3+3 dose escalation scheme was used to determine the MTD of carfilzomib, with the following dose levels evaluated: 36, 45, and 56 mg/m2. Carfilzomib (30-minute infusion) was administered on days 1, 2, 8, 9, 15, and 16 of each 28-day cycle, beginning with 20 mg/m2 on days 1 and 2 of cycle 1, then stepping up to the assigned dose level. In each cycle, cyclophosphamide (oral, 300 mg/m2) was administered on days 1, 8, and 15, and dexamethasone (oral or intravenous, 40 mg) was administered on days 1, 8, 15, and 22. An expansion cohort was enrolled at the established MTD or the maximum planned dose (MPD). Results: There were no dose-limiting toxicities observed at any of the dose levels evaluated, and thus the MPD of 56 mg/m2 was brought forward into dose expansion. A combined total of 16 patients (dose escalation + dose expansion) received carfilzomib at 56 mg/m2. The median age of patients who received KCyd at 56 mg/m2 was 65 years (range, 49-81), 56.3% were male, and 93.8% had an ECOG performance status of 0 or 1. At 56 mg/m2,the ORR was 87.5% (95% CI, 61.7%-98.4%), and best overall responses were complete response (n = 1); very good partial response (n = 7); partial response (n = 6); and stable disease (n = 2). The median TTR for patients who received the 56 mg/m2 dose and achieved partial response or better was 1 month. At 56 mg/m2,the most common adverse events of any grade were nausea (68.8%), cough (62.5%), diarrhea (56.3%), anemia (50.0%), fatigue (50.0%), and headache (43.8%), and the most common grade ≥ 3 adverse events were anemia (25.0%), hypokalemia (18.8%), neutropenia (18.8%), acute kidney injury (12.5%), and decreased white blood cell count (12.5%). Any-grade peripheral neuropathy was reported for 1 patient treated with the 56 mg/m2 dose. The mean number of treatment cycles started among patients who received the 56 mg/m2 dose was 7 (range, 3-8). In total, 6 of the 16 patients who received carfilzomib at 56 mg/m2 did not complete the 8 cycles of study treatment: 1 patient discontinued due to progressive disease (which manifested during a break in treatment for renal insufficiency), 1 patient withdrew from the study, and 4 patients discontinued treatment because of adverse events. Adverse events that led to treatment discontinuation were acute renal failure (n = 1), creatinine increase and dehydration (n = 1), intermittent nausea (n = 1), and urinary tract infection (n = 1). One patient in the 45 mg/m2 cohort experienced death due to sudden cardiac arrest; no deaths in the 36 or 56 mg/m2 cohorts occurred during the study. Conclusions: Carfilzomib administered at 56 mg/m2 twice weekly in combination with cyclophosphamide and dexamethasone was effective and showed acceptable toxicity for treating patients with newly diagnosed MM. The CHAMPION-2 study suggests that KCyd may be considered for first-line treatment of MM, including for patients not eligible for transplant. Acknowledgments: This study was supported by Onyx Pharmaceuticals, Inc. an Amgen, Inc. subsidiary. The authors would like to thank Jesse Potash of Amgen, Inc. for medical writing assistance. Disclosures Boccia: Celgene: Consultancy, Honoraria, Speakers Bureau; Amgen/Onyx: Consultancy, Honoraria, Speakers Bureau; Genentech: Consultancy, Honoraria, Speakers Bureau; Gilead: Speakers Bureau; Eisai: Consultancy, Honoraria, Speakers Bureau. Conkling:USOncology Research: Research Funding; Amgen Inc.: Research Funding. Harb:Amgen Inc.: Consultancy. Yang:Amgen Inc.: Employment, Equity Ownership. Pinchasik:Amgen Inc.: Employment, Equity Ownership. Kimball:Amgen Inc.: Employment, Equity Ownership. Berenson:OncoTracker: Employment, Equity Ownership.

Description: Introduction: Carfilzomib is an irreversible proteasome inhibitor that is approved as a single agent in the United States and other countries for the treatment of relapsed and refractory multiple myeloma (MM); carfilzomib in combination with lenalidomide (LEN) and dexamethasone is also approved in the United States for the treatment of relapsed MM. The approved dose and schedule of carfilzomib is a twice-weekly, 10-min intravenous (IV) infusion on days 1, 2, 8, 9, 15, and 16 of 28-day cycles (starting dose: 20 mg/m2 [days 1 and 2 of cycle 1]; escalated to a target dose of 27 mg/m2 thereafter). Here we present updated results from the multicenter, phase 1/2 study CHAMPION-1 (NCT01677858), which evaluated the safety and efficacy of once-weekly carfilzomib with dexamethasone (Kd) in patients with relapsed or refractory MM. Methods: Patients with relapsed or refractory MM (1-3 prior lines of therapy) were eligible. Patients received carfilzomib as a 30-min IV infusion on days 1, 8, and 15 of 28-day cycles. The phase 1 portion of the study utilized a standard 3+3 dose-escalation scheme. All patients received carfilzomib at 20 mg/m2 on day 1 of cycle 1; patients received 45, 56, 70, or 88 mg/m2 beginning on day 8 of cycle 1 in successive dose-level cohorts until the maximum tolerated dose (MTD) was reached. All patients received dexamethasone 40 mg (IV or oral administration) on days 1, 8, 15, and 22 of cycles 1-8; dexamethasone was omitted on day 22 in cycles ≥ 9. In the phase 2 portion, patients received carfilzomib at the MTD (carfilzomib dose of 20 mg/m2 on cycle 1, day 1; escalating to the MTD for subsequent doses) and dexamethasone at the same dose and schedule. Kd was administered until unacceptable toxicity or disease progression. The primary objective of the phase 1 portion was to determine the MTD of carfilzomib in the Kd regimen; the primary objective of the phase 2 portion was to determine the overall response rate (ORR [≥partial response]). Blood samples were collected for pharmacokinetic and pharmacodynamic analyses. Results: A total of 27 patients were enrolled in phase 1; the MTD of carfilzomib was determined to be 70 mg/m2. Results are presented for all patients treated with Kd at the carfilzomib MTD in both the phase 1b (n=15) and phase 2 (n=89) portions of the study. Among these 104 patients, median patient age was 68.5 years (range, 41-88). Patients received a median of 1 prior line of therapy (range, 1-3); 83% of patients had received prior bortezomib (BTZ), 49% of patients were BTZ-refractory, 27% were LEN-refractory, and 16% were refractory to both BTZ and LEN. Median carfilzomib treatment duration was 7.7 months (range, 0.03-24.2). The ORR was 77% (95% confidence interval [CI]: 68%-85%); the clinical benefit rate (≥minimal response) was 84% (95% CI: 75%-90%). Kaplan-Meier median progression-free survival was 12.6 months (95% CI: 9.0-not estimable). Twelve patients (12%) discontinued treatment due to an adverse event. The most common adverse events of any grade and of grade ≥3 are shown in the Table. Five patients died on study: 1 patient each had cause of death reported as disease progression, acute respiratory distress syndrome, acute respiratory failure, acute kidney injury, and cardiopulmonary arrest. The mean area under the curve and maximum concentration following a 70-mg/m2 carfilzomib dose was 1050 ng×h/mL and 2510 ng/mL, respectively. At 1 hour post dosing of carfilzomib 70 mg/m2, the activity of the predominant chymotrypsin-like proteasome catalytic subunit in peripheral blood mononuclear cells (ie, low molecular mass polypeptide 7) was strongly inhibited (97% inhibition as determined by an enzyme-linked immunosorbent assay [ProCISE]; 93% inhibition as determined by a fluorogenic substrate assay). Conclusions: CHAMPION-1 is the first clinical study to evaluate carfilzomib on a weekly dosing schedule. Once-weekly carfilzomib (70 mg/m2) with dexamethasone demonstrated acceptable safety and tolerability with promising efficacy for patients with relapsed or refractory MM. The dose and schedule of carfilzomib used in the CHAMPION-1 study (20/70 mg/m2) is currently being compared with the regulatory-approved carfilzomib dose and schedule (20/27 mg/m2 administered twice-weekly) in the ongoing, phase 3, superiority study ARROW (NCT02412878). Disclosures Lyons: Amgen: Consultancy, Honoraria; Insyte: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Harb:Onyx Pharmaceuticals: Consultancy. Boccia:Incyte Corporation: Honoraria. Moss:Onyx: Honoraria, Research Funding. Rifkin:Onyx Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees. Schupp:Amgen: Employment, Equity Ownership. Dixon:Onyx/Amgen: Employment, Equity Ownership. Ou:Onyx/Amgen: Employment, Equity Ownership. Anderl:Onyx/Amgen: Employment, Equity Ownership. Berdeja:Abbvie: Research Funding; BMS: Research Funding; Acetylon: Research Funding; Celgene: Research Funding; Takeda: Research Funding; Onyx: Research Funding; Janssen: Research Funding; Novartis: Research Funding; MEI: Research Funding; Array: Research Funding; Curis: Research Funding.

Description: Introduction. wAIHA is a rare and often serious disease in which red blood cells (RBCs) coated with autoantibodies bind to Fcγ receptor-bearing macrophages, triggering a spleen tyrosine kinase (SYK) dependent signaling pathway that leads to RBC phagocytosis. Fostamatinib is a potent SYK inhibitor administered orally that was approved by the US FDA for the treatment of chronic ITP in adults. A phase 2, multicenter, open-label study (the SOAR study; NCT02612558) evaluated the response to fostamatinib in adult patients with wAIHA. We report the final results of the initial 24-week treatment period and the extension period of the phase 2 study. Methods. The study included adult patients with primary or secondary wAIHA, documented by IgG positive direct antiglobulin test (DAT), who had: failed ≥1 prior treatment for wAIHA, hemoglobin (Hgb) 10 g/dL with an increase of ≥2 g/dL from baseline by Week 24 without rescue therapy or RBC transfusion. Patients who responded or showed clinical benefit were allowed to enter the extension period as long as they were tolerating the study drug. Results. The study included 25 evaluable patients (15 women) with median age 61 (range 27-88) years, median duration of wAIHA of 2 years (2.0 g/dL from baseline by Week 4 vs. no change for nonresponders. 13 eligible patients entered the extension period of the study, including 9 of 11 responders, 1 late responder, and 3 patients with a beneficial trend. Seven patients are still on treatment, and 6 discontinued the study, including 3 who withdrew, 1 was lost to follow up, and 2 had a loss of response (1 of whom also had increased alanine aminotransferase). Overall, adverse events (AE) were manageable and consistent with the fostamatinib safety database of 〉3500 patients across all disease programs. No new safety signals were detected. The most common AEs during the initial treatment period were diarrhea in 9, fatigue in 8, hypertension in 7, and dizziness in 6. AEs were mostly mild to moderate. Seven patients had serious AEs, including anemia, acute myocardial infarction, fall, Hgb decreased, inappropriate secretion of antidiuretic hormone, infection, pneumonia, rhabdomyolysis, sepsis, skin necrosis, and systemic inflammatory response syndrome. Two patients had AEs leading to death: one had infection with skin necrosis and calciphylaxis; the other had pneumonia. Neither were considered related to treatment, and both patients were immunosuppressed due to steroids. Six subjects (24%) received rescue therapy, including RBC transfusion, prednisone and/or immunoglobulins. Conclusions. In this phase 2, multicenter, open-label study, fostamatinib markedly improved Hgb levels in 48% of 25 evaluable patients with wAIHA. Adverse events were manageable and consistent with those previously reported with fostamatinib in other conditions. Figure Disclosures Rogers: Janssen: Research Funding; AbbVie: Research Funding; Genentech: Research Funding; Acerta Pharma: Consultancy. Boxer:Arizona Oncology: Employment; Incyte: Speakers Bureau; Best Doctors: Consultancy; Abbvie: Honoraria, Speakers Bureau; Gerson Lerman: Consultancy; Rigel: Speakers Bureau; Takeda: Honoraria, Speakers Bureau. Choi:Oncternal: Research Funding; Gilead: Consultancy, Speakers Bureau; Abbvie: Consultancy, Research Funding, Speakers Bureau; Rigel: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding, Speakers Bureau; Genentech: Consultancy, Speakers Bureau. Arnold:Novartis: Honoraria, Research Funding; Rigel: Consultancy, Research Funding; Principia: Consultancy; Bristol-Myers Squibb: Research Funding. Broome:Cellphire: Research Funding; Alexion: Honoraria, Research Funding; Incyte: Research Funding; Sanofi Genzyme: Honoraria, Research Funding; Rigel: Research Funding. Field:Ironwood: Consultancy, Research Funding; Rigel: Research Funding; Prolong: Research Funding; Incyte: Research Funding. Murakhovskaya:Momenta: Membership on an entity's Board of Directors or advisory committees. Chow:Rigel: Employment, Equity Ownership. Numerof:Rigel: Employment, Equity Ownership. Zheng:Rigel: Employment, Equity Ownership. Tong:Rigel: Employment, Equity Ownership. Kuter:Sanofi: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Dova: Consultancy, Honoraria; Agios: Consultancy, Honoraria, Research Funding; Genzyme: Consultancy, Honoraria; Alnylam: Consultancy, Honoraria, Research Funding; Agios: Consultancy, Honoraria, Research Funding; Alnylam: Consultancy, Honoraria, Research Funding; Bristol Myers Squibb (BMS): Consultancy, Honoraria, Research Funding; Daiichi Sankyo: Consultancy, Honoraria; Shinogi: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Momenta: Consultancy, Honoraria; Rigel: Consultancy, Honoraria, Research Funding; Rigel: Consultancy, Honoraria, Research Funding; Genzyme: Consultancy, Honoraria; Shinogi: Consultancy, Honoraria; Shire: Consultancy, Honoraria; Principia: Consultancy, Honoraria, Research Funding; Protalix: Consultancy, Honoraria; Protalex: Consultancy, Honoraria, Research Funding; Principia: Consultancy, Honoraria, Research Funding; Argenx: Consultancy, Honoraria, Research Funding; Protalix: Consultancy, Honoraria; Platelet Disorder Support Association: Consultancy, Honoraria; Kezar: Research Funding; Actelion (Syntimmune): Consultancy, Honoraria, Research Funding; Caremark: Consultancy, Honoraria; Bristol Myers Squibb (BMS): Consultancy, Honoraria, Research Funding; Caremark: Consultancy, Honoraria; Daiichi Sankyo: Consultancy, Honoraria; Kyowa-Kirin: Consultancy, Honoraria; Kyowa-Kirin: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; UCB: Consultancy, Honoraria; Takeda (Bioverativ): Consultancy, Honoraria, Research Funding; Up-to-Date: Consultancy, Honoraria, Patents & Royalties: 3 Up-to-Date chapters; UCB: Consultancy, Honoraria; Zafgen: Consultancy, Honoraria; Up-to-Date: Consultancy, Honoraria, Patents & Royalties: 3 Up-to-Date chapters; Zafgen: Consultancy, Honoraria; Protalex: Consultancy, Honoraria, Research Funding; Dova: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Platelet Disorder Support Association: Consultancy, Honoraria; Takeda (Bioverativ): Consultancy, Honoraria, Research Funding; Shire: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Merck Sharp Dohme: Consultancy, Honoraria; Argenx: Consultancy, Honoraria, Research Funding; Kezar: Research Funding; Momenta: Consultancy, Honoraria; Merck Sharp Dohme: Consultancy, Honoraria; Actelion (Syntimmune): Consultancy, Honoraria, Research Funding. OffLabel Disclosure: Fostamatinib is a tyrosine kinase (SYK) inhibitor for the treatment of adult patients with chronic immune thrombocytopenia (ITP) who have had an insufficient response to a previous treatment. The use of fostamatinib in other diseases is off-label.