Prediction of Response to Fostamatinib Based on the Presence of Plasma Platelet Autoantibodies in Adult Patients with Immune Thrombocytopenia (ITP) — Exploratory Analyses from Phase 3 Studies
Abstract Background: Initial results of an analysis of anti-platelet autoantibodies in patients with ITP from two phase 3 studies showed that patients were more likely to respond to treatment with the SYK inhibitor fostamatinib if they were positive for anti-platelet autoantibodies. Stable platelet responses to fostamatinib were reported in 36% of 28 patients who tested positive for anti-platelet autoantibodies and in 9% of 32 patients who tested negative (p<0.02). This analysis has been expanded to include 85 patients and to evaluate various platelet antigens. Methods: Plasma samples from 85 patients in the phase 3 studies were collected with informed consent at 2 weeks after the first dose of fostamatinib. Samples were analyzed for anti-platelet autoantibodies via Luminex beads-based PakLx assayand FACS-based indirect platelet immunofluorescence test (iPIFT) using platelets from healthy volunteers. Results: Of 85 patient samples, 38 (45%) were positive for one or more anti-platelet autoantibodies and 19 (22%) were from patients with a stable platelet response to fostamatinib. Of 38 patients positive for autoantibodies, 13 (34%) had stable platelet responses. Of 47 patients negative for autoantibodies, 6 (13%) had stable platelet responses. Conclusions: The presence of anti-platelet autoantibodies appeared to be associated with a stable platelet response to fostamatinib. This exploratory analysis provides support for the hypothesis that fostamatinib prevents platelet loss through inhibition of autoantibody-directed platelet destruction in ITP. Further studies are ongoing. Disclosures Markovtsov: Rigel: Employment, Equity Ownership. Yi:Rigel: Employment, Equity Ownership. Young:Rigel: Employment, Equity Ownership. Duliege:Rigel: Employment, Equity Ownership. Masuda:Rigel Pharmaceuticals: Employment, Equity Ownership.
Abstract Introduction. The phase 3 randomized, placebo-controlled trials of the SYK inhibitor fostamatinib in adult patients with ITP were followed by an open-label extension (OLE) study to examine durability of response to fostamatinib and to allow patients in the placebo group in the phase 3 trials to crossover to fostamatinib. This abstract provides an additional year of data from the OLE study in patients with up to 3 years of fostamatinib treatment. Methods. Patients were adults with persistent or chronic ITP who had failed ≥1 prior therapy and had ≥3 platelet counts below 30,000/μL at screening. Patients initiated fostamatinib treatment at 100mg BID PO and increased to 150 mg BID based on tolerability and if platelets were <50,000/μL after 1 month. A stable platelet response was defined as a platelet count ≥50,000/μL that was maintained during the second 12-week period of fostamatinib treatment. The pre-specified analysis in the OLE study was the achievement and maintenance of a stable platelet response for 12 months. A post-hoc analysis was conducted on overall response, defined as achieving ≥1 platelet count of ≥50,000/µL within 12 weeks of beginning active treatment. All analyses excluded counts within 4 weeks of a rescue therapy. The data cutoff is 8 March 2018. Results. In the OLE study, 123 patients received fostamatinib, including 44 who had received placebo in the phase 3 studies. At baseline, the median age was 52 years (range 20-88), and 7% had persistent ITP (<12 months duration). The median duration of disease was 8.4 years, and the median platelet count was 16,000/μL at the start of treatment. Prior to the phase 3 studies, patients had tried a median of 3 (range 1-13) unique ITP treatments including splenectomy (35%; median 13 years earlier), corticosteroids (95%), immunoglobulins (53%), TPO-RA (47%), immunosuppressants (43%), and rituximab (32%). The median duration of fostamatinib exposure was 8.9 months (range 1.5-41.3). The median treatment compliance was 98%. At the time of analysis, 42 of 123 subjects (34%) continued fostamatinib treatment. Main reasons for discontinuation included lack of a platelet response after Week 12 (36%), study-specific adverse event (AE) (7%), and other AEs (7%). Of 27 patients with a stable response, 21 (78%) have maintained the response at Month 12 of fostamatinib treatment, and 15 (56%) at Month 24. At Month 12, median platelet count for the 49 subjects with data at that time point was 72,000/µL (range: 9000-333,000 µL). For the 32 subjects with data at Month 24, median platelet count was 80,500/µL (range: 7000-315,000/µL). See figure. An overall platelet response was achieved by 57/123 (46%) patients. AEs were reported by 95 (77%) patients and were mild/moderate in 92 (75%). See table. The most common AEs were diarrhea and hypertension, which were manageable with targeted treatment, fostamatinib dose modifications, or treatment withdrawal (5 patients withdrew due to diarrhea and none due to hypertension). Serious adverse events (SAE) were reported in 28 patients (23%), were considered unrelated to fostamatinib in 23 patients (19%) and included bleeding-related SAEs in 11 subjects (9%), thrombocytopenia in 6 subjects (5%), epistaxis in 3 (2%), sepsis in 2 (2%) and transaminases increased in 2 (2%). Adverse events were consistent with those reported during the placebo-controlled trials. Conclusion. In this open-label extension study of the two phase 3, placebo-controlled trials, 56% of subjects with a stable response maintained the response for ≥24 months. No new safety signals have been detected during long-term treatment of ITP with fostamatinib. Figure. Figure. Disclosures Duliege: Rigel: Employment, Equity Ownership. Arnold:UCB: Consultancy; Amgen: Consultancy, Research Funding; UCB: Consultancy; Amgen: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Bristol Myers Squibb: Research Funding; Novartis: Consultancy, Research Funding; Bristol Myers Squibb: Research Funding. Boccia:Amgen: Research Funding, Speakers Bureau; Pfizer: Consultancy; Abbvie: Speakers Bureau; AstraZeneca: Research Funding, Speakers Bureau; Celgene: Speakers Bureau; Sandoz: Consultancy; Genentech: Research Funding, Speakers Bureau; BMS: Research Funding. Boxer:Rigel: Speakers Bureau; Incyte: Speakers Bureau; AbbVie: Speakers Bureau. Cooper:Amgen, Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Hill:Novartis: Honoraria; Novartis: Honoraria. Zayed:Rigel: Employment, Equity Ownership. Tong:Rigel: Employment, Equity Ownership. Bussel:Uptodate: Honoraria; Protalex: Consultancy; Novartis: Consultancy, Research Funding; Prophylix: Consultancy, Research Funding; Momenta: Consultancy; Amgen Inc.: Consultancy, Research Funding; Rigel: Consultancy, Research Funding.
Abstract Abstract 3704 Introduction: Chronic immune thrombocytopenia (ITP) is an autoimmune disorder characterized by both increased platelet destruction and decreased platelet production. Romiplostim increases platelet counts by binding and activating the thrombopoietin receptor. Romiplostim has been approved for the treatment of adult ITP in the United States, Europe, Canada, and Australia. This study evaluated dosing, efficacy, and safety in a Japanese population of adults with ITP. Methods: This phase 3 study was placebo-controlled, double-blind, and randomized 2:1 (romiplostim:placebo). Patients were eligible for the study if they were Japanese patients with ITP diagnosed at least 6 months before the initial screening, were aged ≥ 20 years, and were H pylori negative or had received at least 1 treatment for H pylori eradication. Patients were stratified by splenectomy status (yes or no). After a 3-week evaluation period, patients were treated for 12 weeks with a weekly subcutaneous injection of either romiplostim or placebo. The starting dose was 3 mcg/kg with dose adjustments to a maximum of 10 mcg/kg to achieve a platelet count within the target range of ≥ 50 to ≤ 200 × 109/L. Patients were monitored posttreatment until their platelet count dropped to ≤ 50 × 109/L or for a maximum of 12 weeks. The primary endpoint was number of weeks with platelet response (platelet count ≥ 50 × 109/L). Results: Thirty-four patients enrolled (22 romiplostim, 12 placebo), 24 (71%) were female, the median (range) age was 55 (44 - 64) years, and the median (range) baseline platelet count was 19 (3 – 32) × 109/L. Patients had received a median of 4 (1 – 19) prior ITP therapies, and 15 (44%) had previously undergone a splenectomy; 23 (68%) patients were receiving concurrent ITP therapy at baseline. All patients completed the study. Romiplostim demonstrated superiority to placebo on weekly platelet response, incidence of increase in platelet count ≥ 20 × 109/L from baseline, change from baseline in mean of last 4 platelet counts during week 2 to week 13, and number of weeks with platelet counts within the target range (Table 1), and 16 (73%) romiplostim patients had platelet counts ≥ 200 × 109/L. Twenty-one (95%) patients in the romiplostim group had a platelet response with a median time of 1 week until first response. Results for weekly platelet response were comparable irrespective of splenectomy status and baseline concurrent ITP therapy. Two (17%) patients in the placebo group achieved a platelet response. In romiplostim-treated patients, posttreatment platelet counts remained > 50 × 109/L for 8 weeks in one and for 12 weeks in another. The mean weekly dose of romiplostim for the study was 2.6 mcg/kg compared with the dose range of 3–4 mcg/kg in prior phase 3 studies (Kuter et al. Lancet. 2008;371:395–403). There was a low incidence of rescue medication use in the study (Table 1). The adverse events profile was comparable to that seen in non-Japanese studies. Patients in both treatment groups experienced similar proportions of adverse events (91% romiplostim, 92% placebo). Adverse events with > 10% higher frequency in the romiplostim group than placebo group) were (romiplostim, placebo) nasopharyngitis (41%, 17%), headache (32%, 17%), peripheral edema (18%, 0%), back pain (14%, 0%), and pain in extremity (14%, 0%). Significant (≥ grade 3) bleeding events occurred in 1 patient in the romiplostim group (subarachnoid hemorrhage) and 1 patient in the placebo group (subarachnoid hemorrhage, cerebral hemorrhage, and gastrointestinal hemorrhage). There were no adverse events of bone marrow reticulin, thrombosis, or detection of neutralizing antibodies. Conclusion: Romiplostim significantly increased and maintained platelet counts and was well-tolerated in a Japanese ITP population. Disclosures: Tomiyama: Kyowa Hakko Kirin Co.: Speakers Bureau; GlaxoSmithKline: Speakers Bureau. Kurokawa:Novartis: Consultancy; Shionogi & Co., Ltd.: Consultancy. Wei:Amgen Inc.: Employment, Equity Ownership. Lizambri:Amgen Inc.: Employment, Equity Ownership.
Abstract Abstract 4362 Midostaurin (PKC412) is a multi-targeted tyrosine kinase inhibitor (TKI) of several receptors, including wild-type and mutant variants of KIT and the FMS-like tyrosine kinase 3 (FLT3) receptor, and has known roles in hematopoiesis and leukemia. Midostaurin has demonstrated activity in acute myeloid leukemia (AML) and myelodysplastic syndrome in phase 1 and 2 trials, and is currently under investigation in a randomized phase 3 AML study at 50mg twice daily (bid) in combination with chemotherapy and a phase 2 monotherapy study of aggressive systemic mastocytosis (ASM) at 100mg bid. Despite the absence of specific midostaurin-related cardiac toxicity issues, we conducted a dedicated phase 1 study to directly investigate the effect of midostaurin on QTc interval. Healthy subjects were randomized to 3 treatment arms: placebo; midostaurin administered orally at 75mg bid on days 1 and 2 and once daily (od) on day 3; or an active control arm of moxifloxacin administered orally at 400mg od on day 3. The primary variable was QTcF interval on day 3 corrected for baseline and placebo in the midostaurin and moxifloxacin treatment arms. Drug exposure levels at each time point were confirmed for moxifloxacin, midostaurin, and its two metabolites – CGP62221 and CGP52421. Of 192 subjects enrolled, 166 completed the study. 24 of 80 subjects discontinued in the midostaurin arm: 19 (23%) due to adverse events (AEs), 17 of which encompassed expected gastrointestinal events. No patients were discontinued for AEs in the other 2 treatment groups. Discontinued patients were not included in the ECG analysis. In time-matched analysis of QTcF interval change, the maximum mean change in the midostaurin arm corrected for baseline and placebo was 0.72ms with a 90% confidence interval (CI) upper bound of 4.71ms, which excluded 10ms. At each nominal time point, the mean change from baseline placebo-corrected for midostaurin was <0ms. The QTcF change point estimate corrected for time-averaged baseline and placebo also showed a lack of QTc prolongation for midostaurin. Moxifloxacin had a maximum mean change corrected for baseline and placebo of 10.7ms with a lower unadjusted 90% CI of 6.4ms 1 hour post-dose on day 3. Plasma concentration vs QTcF change from baseline analysis confirmed a negative or lack of QT effect by midostaurin but a positive correlation for moxifloxacin. No symptomatic, clinically significant new post-baseline morphological abnormalities were identified in the study. 3 patients in the midostaurin group at a single time point or evaluation experienced new post-baseline T-wave abnormalities, as did 1 and 4 patients in the placebo and moxifloxacin groups, respectively, some at multiple time points. No subject had a new >30ms or >480ms change from baseline for QTcF or QTcI. For QTcB the only occurrences of change were in the 30–60ms category: 1 (1.3%) of the subjects on midostaurin met this non-specific outlier criterion; 7 (15.9%) on moxifloxacin; and 1 (1.5%) on placebo. 1 new U-wave abnormality was noted in the moxifloxacin group. The peak plasma concentration of midostaurin achieved in the present study (mean 2273ng/mL) covered the peak and trough plasma exposure observed at 50mg bid (2220ng/mL and 1005ng/mL, respectively) in AML patients. The peak level achieved for midostaurin was also above the steady-state trough level of 1060ng/mL, but below the peak concentration of 3500ng/mL, for the 100mg bid dose. Midostaurin was safe and generally well tolerated: 97% of the AEs noted in subjects while on study drug (n=61; 40%) were reported as grade 1. No grade 3/4 AEs were reported. While some TKIs exert pharmacologic effects on QTc interval, this carefully conducted trial demonstrates that midostaurin at 75mg bid has no effect on heart rate, AV conduction, or cardiac depolarization. The midostaurin exposure achieved in this study exceeds the peak and trough levels for the 50mg bid dose regimen under investigation in the AML phase 3 trial. The midostaurin exposure achieved also exceeds the steady state trough level, but not the peak level, of the 100mg bid dose regimen under investigation in the phase 2 ASM trial. Further, the effects of the long-acting metabolite CGP52421 cannot be fully addressed by this short study. Due to the lack of QT prolongation observed in this trial, we recommend reduced but continued ECG monitoring and omission of QT-related exclusion criteria in future midostaurin clinical trials. Disclosures: del Corral: Novartis Pharmaceuticals Corporation: Employment. Dutreix:Novartis Pharmaceuticals Corporation: Employment. Huntsman Labed:Novartis Pharmaceuticals Corporation: Employment. Rai:Novartis Pharmaceuticals Corporation: Employment. Grosch:Novartis Pharmaceuticals Corporation: Employment. Morganroth:eResearchTechnology Inc: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Novartis Pharmaceuticals Corporation: Consultancy, Research Funding. Wang:Novartis Pharmaceuticals Corporation: Employment, Equity Ownership.
Abstract Abstract 1704 Background: Lenalidomide (LEN) is approved in the US for the treatment of RBC transfusion-dependent patients with IPSS Low- or Int-1-risk myelodysplastic syndromes (MDS) with del(5q), with or without other cytogenetic abnormalities. In a phase 3 trial, treatment with LEN 5 mg and 10 mg resulted in RBC transfusion independence (TI) for ≥ 26 weeks in 43% and 56% of such patients, cytogenetic response in 25% and 50%, and a significant improvement of health-related quality of life (p <.05 for both 5 mg and 10 mg). Achievement of RBC-TI ≥ 8 weeks was associated with a significantly reduced risk of AML progression and death (p <.05 for both) (Fenaux P et al. Blood 2011;doi: 10.1182/blood-2011-01-330126). In newly diagnosed multiple myeloma patients, results of phase 3 trials showed a numerical imbalance in the occurrence of second primary malignancies (SPMs) between patients treated with LEN (in combination with melphalan or immediately after high-dose melphalan therapy and stem cell transplantation) and control cohorts. SPMs were analyzed in clinical trials of LEN across indications, including MDS. Methods: This was a single arm analysis of SPM data retrieved from RBC transfusion-dependent patients with IPSS Low- or Int-1-risk MDS with or without del(5q) who received LEN as monotherapy in 5 studies (MDS-001, -002, -003, -004, and -007). The cutoff date was February 28, 2011. SPMs were defined using MedDRA (Medical Dictionary for Regulatory Activities) categories of invasive SPMs (hematologic malignancies and solid tumors) and non-melanoma skin cancers (NMSC). Acute myeloid leukemia (AML) is considered part of the natural history of disease progression in MDS. Although further follow-up is needed, results of a phase 3 study showed no obvious evidence for an increased risk of AML progression in LEN-treated RBC transfusion-dependent patients with IPSS Low- or Int-1-risk MDS and del(5q) (Fenaux P et al. Blood 2011;doi: 10.1182/blood-2011-01-330126). AML was not included in the present analysis. The overall number of SPMs (invasive malignancies and NMSC), and the number and incidence rate (IR) of all invasive SPMs were evaluated, with IR defined as the number of new events per 100 person-years (pys). The IR of invasive SPMs was compared with the IR of new events of invasive cancer as reported from the SEER (Surveillance, Epidemiology, and End Results) cancer registry (2.1/100 pys for persons aged ≥ 65 years) (Howalder N et al. National Cancer Institute, 2011). Results: The combined population of all 5 studies comprised 557 LEN-treated patients. The median age was 71 years (range 27–95 years) and 72% of patients were aged ≥ 65 years. 88 patients (15.8%) had a prior history of cancer including malignant melanoma, meningioma, breast cancer, lung cancer, squamous cell carcinoma, and basal cell carcinoma. A total of 28 patients (5.0%) developed ≥ 1 SPM, including 17 (3.1%) with an invasive SPM and 12 (2.2%) with NMSC; 1 patient had both an invasive malignancy and a NMSC. Two of the 17 patients with invasive SPMs had a B-cell malignancy and 15 had solid tumors of heterogeneous type. Of the 28 patients with SPMs in total, 5 patients had a prior history of cancer. The IR of invasive SPMs was 2.60/100 pys (95% confidence interval 1.56–4.07), which is consistent with the IR reported in the SEER database among patients in this age group (2.1/100 pys for persons aged ≥ 65 years). The median time to onset of SPMs was 13.5 months (range 0.3–48.6 months). Conclusion: There was no clear evidence to associate LEN treatment with an increased risk of developing SPMs in patients with Low- or Int-1-risk MDS with or without del(5q). The IR of invasive SPMs among these LEN-treated patients is what would be expected from population-based estimates of invasive cancer incidence among persons in this age group. The collection of data on SPMs in LEN-treated patients including post-marketing information is ongoing. Disclosures: Giagounidis: Celgene Corporation: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. List:Celgene Corporation: Consultancy, Honoraria, Research Funding. Fenaux:Merck: Honoraria; Johnson & Johnson: Honoraria; Amgen: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Celgene Corporation: Honoraria, Research Funding; Cephalon: Honoraria; Novartis: Honoraria. Benettaib:Celgene Corporation: Employment, Equity Ownership. Brown:Celgene Corporation: Employment, Equity Ownership. Zhong:Celgene Corporation: Employment, Equity Ownership. Brandenburg:Celgene Corporation: Employment, Equity Ownership. Mufti:Celgene Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.
Abstract Abstract 3279 Background: ITP is an autoimmune disorder characterized by increased platelet destruction and suboptimal platelet production. Romiplostim stimulates platelet production via the TPO-receptor, and is recommended for second- and third-line treatment of chronic ITP in adults. We report final data from a large prospective study of romiplostim in adults with ITP of varying duration and severity. Methods: Eligibility criteria were broad: patients ≥18 years of age, who had received prior ITP therapies (final protocol amendment: ≥1, previous amendments: ≥3), with low platelet counts (final amendment: ≤ 30 × 109/L, previous amendments: ≤ 10, ≤ 20 × 109/L) or experiencing uncontrolled bleeding. The only excluded comorbidities were: hematological malignancy, myeloproliferative neoplasms, MDS and bone marrow stem cell disorder. Romiplostim was initiated at 1 (final amendment) or 3 (previous amendments) μg/kg/week, with dose adjustments allowed to maintain platelet counts ≥50 × 109/L. Patients could continue on study until they had access to commercially available romiplostim. Rescue medications were allowed at any time; concurrent ITP therapies could be reduced when platelet counts were > 50 × 109/L. Primary endpoint was incidence of adverse events (AEs) and antibody formation. Secondary endpoint was platelet response, defined as either (1) doubling of baseline count and ≥ 50 × 109/L or (2) ≥20 × 109/L increase from baseline. Results: A total of 407 patients received romiplostim, 60% of whom were female. Median (Q1, Q3) time since ITP diagnosis was 4.25 (1.20, 11.40) years (maximum 57.1 years), with 51% of patients splenectomised and 39% receiving baseline concurrent ITP therapies. Seventy-one percent of patients completed the study, with requirement for alternative therapy and withdrawn consent the most common reasons for discontinuation (5% each). Median (Q1, Q3) on-study treatment duration was 44.29 (20.43, 65.86) weeks (maximum 201 weeks), with a total of 20,201 subject-weeks on study. Incidence and type of AEs were consistent with previous studies. The most common serious treatment-related AEs were cerebrovascular accident, headache, bone marrow reticulin fibrosis (with no evidence of positive trichrome staining for collagen and no evidence suggesting primary idiopathic myelofibrosis), nausea, deep vein thrombosis, hemorrhage and pulmonary embolism, with each reported in 2 of 407 (0.5%) patients. All other serious treatment-related AEs were each reported in one patient. Eighteen patients died; 3 deaths (hemolysis, intestinal ischaema, aplastic anemia) were considered treatment-related. No neutralizing antibodies to romiplostim or TPO were reported. Approximately 90% of patients achieved each of the platelet response definitions, regardless of splenectomy status. Overall, median (Q1, Q3) time to response was 2 (1, 4) weeks for response definition 1, and 1 (1, 3) week for response definition 2. Median (Q1, Q3) baseline platelet count was 14 (8, 21) × 109/L. After 1 week of treatment median (Q1, Q3) platelet count had increased to 42 (18, 101) × 109/L. From week 8 onwards, and excluding counts within 8 weeks of rescue medication use, median platelet counts were consistently above 100 × 109/L (range 101.0–269.5 × 109/L). Median (Q1, Q3) average weekly romiplostim dose was 3.62 (1.99, 6.08) μg/kg. Summary/conclusions: This is the largest prospective study in adult ITP reported to date. The data reported here are similar to those reported for previous romiplostim studies, with romiplostim able to safely induce a rapid platelet response in adult ITP patients with low platelet counts or bleeding symptoms. Romiplostim is an important, well-tolerated, treatment option for adult ITP patients, which significantly increases and maintains platelet counts. Adverse Event Subject Incidence Platelet Response Disclosures: Janssens: Amgen: Consultancy; Roche: Speakers Bureau; GSK: Membership on an entity's Board of Directors or advisory committees. Tarantino:Cangene corporation: Research Funding; Baxter: Research Funding; Talecris: Honoraria, Speakers Bureau; Up-to-date: Patents & Royalties; The Bleeding and Clotting Disorders Institute: Board Member. Bird:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; GSK: Membership on an entity's Board of Directors or advisory committees. Boccia:Amgen: Equity Ownership, Honoraria, Speakers Bureau. Lopez-Fernandez:Amgen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Kozak:Amgen: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Steurer:Amgen: Honoraria. Dillingham:Amgen Limited: Employment, Equity Ownership. Lizambri:Amgen: Employment, Equity Ownership.
Abstract Introduction: Panobinostat is a potent pan-deacetylase inhibitor (pan-DACi) that targets key aberrations in multiple myeloma (MM) cell biology, including epigenetics and protein metabolism. In the phase 3 clinical trial PANORAMA 1, panobinostat in combination with bortezomib and dexamethasone (PAN-BTZ-Dex) led to a statistically significant and clinically relevant increase in progression-free survival of approximately 4 months compared with that with placebo plus bortezomib and dexamethasone (Pbo-BTZ-Dex). Further analyses of patient outcomes by prior treatment demonstrated that the magnitude of PFS benefit was greatest among patients who received at least 2 prior regimens, including bortezomib and an immunomodulatory drug (IMiD; PAN-BTZ-Dex [n = 73]: 12.5 months [95% CI, 7.3-14.0 months]; Pbo-BTZ-Dex [n = 74]: 4.7 months (95% CI, 3.7-6.1 mo; HR 0.47 [95% CI, 0.32-0.72]). These data supported the regulatory approvals of PAN-BTZ-Dex for the treatment of patients with multiple myeloma who received at least 2 prior regimens, including bortezomib and an IMiD. Here we present the final analysis of overall survival (OS) for the entire patient population and among patients who received at least 2 prior regimens, including bortezomib and an IMiD. Methods: The study design for the PANORAMA 1 trial was described previously (San-Miguel. Lancet Oncol. 2014;15:1195-206). The key secondary endpoint was OS. As of June 29, 2015, the 415 events required to conduct the final analysis of OS had been observed. Kaplan-Meier estimation was utilized for OS analyses for the entire population (N = 768), the pre-specified subgroup of patients who received prior bortezomib and IMiD (n = 193), and patients who received at least 2 prior regimens including bortezomib and an IMiD (n = 147). Results: The median OS of patients who received PAN-BTZ-Dex in the overall population was 40.3 months (95% CI, 35.0-44.8 months) vs 35.8 months (95% CI, 29.0-40.6 months) for the Pbo-BTZ-Dex arm with HR 0.94 [95% CI, 0.78-1.14], P = .5435 (Fig 1A). The percentage of patients in each arm who received post-study therapy was 37.7% in the PAN-BTZ-Dex arm and 48.8% in the Pbo-BTZ-Dex arm. The median OS of patients who received at least 2 prior lines, including bortezomib and an IMiD, was 25.5 months (95% CI, 19.6-34.3 months) in the PAN-BTZ-Dex arm vs 19.5 months (95% CI, 14.1-32.5 months) in the Pbo-BTZ-Dex arm (Fig. 1B). The proportion of patients in this subgroup who received post-study therapy was 35.6% in the PAN-BTZ-Dex arm and 66.2% in the Pbo-BTZ-Dex arm. Conclusion: For the overall PANORAMA 1 study population, patients in the PAN-BTZ-Dex arm demonstrated an increase in median OS of 4.5 months vs patients in the Pbo-BTZ-Dex arm, but this result was not statistically significant (P = .5435). Median OS was also slightly longer for the PAN-BTZ-Dex arm among the more heavily pretreated subgroup of patients who received at least 2 prior regimens, including bortezomib and an IMiD. A higher percentage of patients on the Pbo-BTZ-Dex arm received post-study therapy vs the PAN-BTZ-Dex arm, which may have confounded the OS results. In summary, PAN-BTZ-Dex demonstrates statistically significant increases in PFS vs Pbo-BTZ-Dex in patients with relapsed or relapsed and refractory MM; however, this did not translate to a statistically significant increase in OS. Future trials will plan to focus on further optimization of dose and schedule of panobinostat and bortezomib to improve outcome, as well as novel combinations with other agents, including IMiDs and next-generation proteasome inhibitors. Figure 2. Figure 2. Disclosures Beksac: Bristol-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen-Cilag: Consultancy, Speakers Bureau. Dimopoulos:Janssen: Honoraria; Janssen-Cilag: Honoraria; Onyx: Honoraria; Amgen: Honoraria; Genesis: Honoraria; Celgene: Honoraria; Novartis: Honoraria. Jedrzejczak:Onconova: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Siritanaratkul:Pfizer: Research Funding; Roche: Research Funding; Novartis: Research Funding; Janssen-Cilag: Research Funding. Schlossman:Millennium: Consultancy. Hou:Novartis: Membership on an entity's Board of Directors or advisory committees. Moreau:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen-Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees; Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees. Lonial:Bristol-Myers Squibb: Consultancy, Research Funding; Millennium: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Onyx: Consultancy, Research Funding; Celgene: Consultancy, Research Funding. Sopala:Novartis Pharma: Employment, Equity Ownership. Bengoudifa:Novartis: Employment. Corrado:Novartis: Employment, Equity Ownership. Richardson:Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Millennium Takeda: Membership on an entity's Board of Directors or advisory committees; Johnson & Johnson: Membership on an entity's Board of Directors or advisory committees.
Introduction Hepatic veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS), is a rare and potentially life-threatening complication of hematopoietic stem cell transplantation (HSCT). Severe cases, historically defined by multi-organ dysfunction (MOD), may be associated with mortality rates of >80%. There is no FDA-approved treatment for VOD/SOS. Defibrotide (DF) has a proposed mechanism of action that includes stabilization of endothelial cells and restoration of thrombo-fibrinolytic balance. Earlier analyses of a pivotal phase 3 trial of DF in VOD/SOS plus MOD (Richardson et al. Blood. 2009;114:Abstract 654) underpinned approval of DF in the EU to treat severe hepatic VOD/SOS after HSCT. Additional data were obtained at the request of US health authorities. Here we present the final analysis: day +100 survival (primary endpoint) and complete response (CR; secondary). Methods This was a multicenter, open-label, phase 3 historical control (HC) study assessing DF. Eligible patients met Baltimore VOD/SOS criteria (total bilirubin ≥2.0 mg/dL with ≥2 of: hepatomegaly, ascites, or 5% weight gain) by day +21 post-HSCT, plus MOD (renal [trebling of creatinine levels, reduced creatinine clearance, or dialysis] and/or pulmonary [oxygen saturation ≤90%, need for oxygen supplementation/ventilator dependence]) by day +28 post-HSCT. Exclusion criteria included severe graft-versus-host disease (GvHD) of liver or gut, clinically significant bleeding, or need for ≥2 pressors. HC patients were reviewed for inclusion/exclusion criteria in a sequential review of medical charts starting 6 months prior to use of DF at each site; a blinded medical review committee made the final determination of HCs unequivocally meeting criteria for VOD/SOS with MOD. DF dose was 25 mg/kg/d in 4 divided 2-hour IV infusions q6h; recommended treatment duration was ≥21 days. Primary endpoint was day +100 survival. CR by day +100 was a secondary endpoint. Treatment difference in survival and CR rates and their 95% confidence intervals were estimated using propensity-stratified and weighted (Koch-adjusted) estimates of differences in proportions that account for baseline prognostic factors of survival (ie, ventilator and/or dialysis dependency at entry, age ≤/>16 years, transplant type, and prior HSCT). Analyses included patients treated with DF and HCs. Results There were 102 patients in the DF group and 32 cases selected as HCs. Baseline characteristics were similar in the DF and HC groups: mean age (26 and 25 years; 43% and 44% ≤16 years), allogeneic graft (88% and 84%), prior HSCT (13% and 9%), ventilator- and/or dialysis-dependent at study entry (33% and 22%), myeloablative conditioning (87% and 94%), and the most common underlying diseases (acute leukemias: 45% and 47%), respectively. In the DF-treated group, common GvHD medications included tacrolimus (49%), methotrexate (41%), and cyclosporine (38%); in the HC group, common medications were cyclosporine (72%) and methotrexate (63%). Survival at day +100 in the DF and HC groups was 38% and 25%, respectively. The propensity-stratified difference in survival was 23.0% (95.1% CI, 5.2-40.8, P = .0109). Respective observed CR rates by day +100 were 25.5% and 12.5%, and the propensity-stratified difference in CR was 19.0% (95.1% CI, 3.5-34.6, P = .0160). Comparing the earlier EU and final analyses, the survival rates at day +100 in each group did not vary; however, the propensity adjusted final analysis provided a different level of statistical significance. Day +100 CR rates in the original analysis were slightly lower in both arms at 24% and 9% due to increased data capture to investigate CR; the P value was essentially unchanged. For the DF group, 45% had an adverse event (AE) at least possibly related to study drug, and 21% had a serious AE at least possibly related to study drug. In this very sick population, percentages of patients with ≥1 AE leading to death were similar between DF and HC patients (64% and 69%), as were hemorrhagic AEs (64%, 75%) and hypotension (39%, 50%). Conclusions Based on observed study data and using a propensity-adjusted rate difference estimator, patients treated with DF had a 23% reduction in risk of death by day +100 and 19% improvement in CR rate. Overall incidence of hemorrhage and fatal AEs were similar between groups with AEs consistent with those expected in this critically ill population. Support: Jazz Pharmaceuticals. Disclosures Richardson: Novartis: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees; Gentium S.p.A.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium Takeda: Membership on an entity's Board of Directors or advisory committees. Off Label Use: Marizomib, pmalidomide, and low dose dexamethasone in RR MM. Defibrotide is an investigational treatment for hepatic veno-occlusive disease/sinusoidal obstruction syndrome in the United States. . Kernan:Gentium S.p.A.: Research Funding. Grupp:Novartis: Consultancy, Research Funding. Guinan:Gentium SpA/Jazz Pharmaceuticals: Other: My institution received fees for research.. Martin:Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Gentium SpA/Jazz Pharmaceuticals: Research Funding. Steinbach:Gentium SpA/Jazz Pharmaceuticals: Research Funding. Krishnan:Celgene: Consultancy, Speakers Bureau; BMS: Consultancy; Janssen: Consultancy; Onyx: Speakers Bureau; Jazz: Consultancy; Millenium: Speakers Bureau. Giralt:SANOFI: Consultancy, Honoraria, Research Funding; CELGENE: Consultancy, Honoraria, Research Funding; AMGEN: Consultancy, Research Funding; JAZZ: Consultancy, Honoraria, Research Funding, Speakers Bureau; TAKEDA: Consultancy, Honoraria, Research Funding. Rodriguez:Gentium SpA/Jazz Pharmaceuticals: Research Funding. Doyle:Gentium SpA/Jazz Pharmaceuticals: Research Funding. Antin:Gentium SpA/Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. D'Agostino:Gentium SpA/Jazz Pharmaceuticals: Consultancy. Massaro:Gentium SpA/Jazz Pharmaceuticals: Consultancy. Miloslavsky:Jazz Pharmaceuticals: Employment, Equity Ownership. Hume:Jazz Pharmaceuticals: Employment, Equity Ownership. Iacobelli:Gentium SpA: Employment. Nejadnik:Jazz Pharmaceuticals: Employment, Equity Ownership. Hannah:Gentium SpA: Other: Personal fees during conduct of the study.. Soiffer:Gentium SpA/Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees.
Abstract Background: Chronic Immune thrombocytopenia (ITP) is characterized by low platelet counts, resulting from increased platelet destruction and inadequate platelet production. Romiplostim is a 59 kDa peptibody which binds to and activates the thrombopoietin (TPO) receptor on platelet precursors in the bone marrow, and increases platelet counts. This analysis integrates the pharmacokinetic (PK) and pharmacodynamic (PD) properties of romiplostim in animals, healthy volunteers and patients with ITP, and describes its intricate PK-PD inter-relationship. Methods and Results: In healthy subjects, over a wide range of doses examined, the PK and PD (platelet response) of romiplostim were dependent on both the dose administered and the baseline platelet counts. Following SC administration, platelet counts increased in a dose-dependent fashion after 4 to 9 days, peaking at 12 to 16 days (Wang Clin Pharmacol Ther. 2004;76:628-38). When romiplostim binds to the TPO receptor on megakaryocytes and platelets, the peptibody-receptor complex is internalized and degraded inside the cells. Therefore, as platelet counts increase, a higher number of free receptors are available to clear romiplostim (Wang AAPS J. 2010;12:729-40). Results from rodent studies suggest that as the dose increases, the TPO receptors become saturated and the contribution of the kidney to clearance increases. Additionally, proteolysis plays a role in the clearance of romiplostim; however, the cytochrome P450 enzymes are not involved in protein catabolism (Wang Pharm Res. 2011;28:1931-8), hence there are no known drug-drug interactions or dietary restrictions (Nplate Prescribing Information 2014). Following SC administration, serum concentrations of romiplostim were markedly lower, however, platelet response was similar after the same dose of intravenous (IV) and SC administration (Wang Clin Pharmacol Ther. 2004;76:628-38). This suggests that the PD response is driven by the length of time that the romiplostim concentrations remained above a threshold rather than by the magnitude of concentrations achieved. This effect was verified in a mechanistic PK-PD modeling study in animals (Krzyzanski Pharm Res. 2013;30:655-69). In patients with ITP receiving SC romiplostim at a dose of 1 mcg/kg, the peak platelet response was achieved at 18 days (range 8 to 43; Bussel N Engl J Med. 2006;355:1672-81). Pharmacodynamic model analysis showed that compared with healthy subjects, patients with ITP had a shorter platelet life span and a decreased rate of production of progenitor cells, but no major difference in the time to maturation of megakaryocytes. The PD response in this modeling analysis was not notably affected by age, body weight, sex, and race (Perez-Ruixo J Clin Pharmacol. 2012;52:1540-51). The frequency of once-weekly dosing was selected because once every 2 weeks dosing was determined to be inadequate to achieve and maintain platelet counts in the therapeutic range (Bussel N Engl J Med. 2006;355:1672-81). A mechanistic PK-PD model based on data from the healthy subjects further suggested that weekly dosing resulted in a sustained platelet response while dosing less frequently resulted in high fluctuation of platelet counts (Wang AAPS J. 2010;12:729-40). Large inter- and intra-individual variability in the PD response was observed at a given dose; therefore, dose adjustments should be made based on a patient's platelet counts, using a titrated dosing scheme to prevent having platelet counts over 400 x 109/L (Perez-Ruixo J Clin Pharmacol. 2012;52:1540-51). Conclusion: Romiplostim is a peptibody that binds and activates the TPO receptor, and consequently increases platelet production in individuals with chronic ITP. The peptibody-receptor complex is internalized and degraded inside the cells, without involvement of the liver. Romiplostim's PD response is driven by the length of time that its concentrations remained above a threshold rather than by the magnitude of concentrations achieved. Moreover, weekly dosing has demonstrated a sustained platelet response while less frequent dosing resulted in fluctuating platelet counts. Disclosures Arkam: Amgen Inc.: Employment, Equity Ownership. Off Label Use: Romiplostim is a thrombopoietin receptor agonist indicated for the treatment of thrombocytopenia in patients with chronic immune thrombocytopenia (ITP) who have had an insufficient response to corticosteroids, immunoglobulins, or splenectomy. This abstract also describes PK data from healthy volunteers.. Doshi:Amgen Inc.: Employment, Equity Ownership. Yang:Amgen Inc.: Employment, Equity Ownership.
Background: Current treatment options for red blood cell (RBC) transfusion-dependent (TD) patients with lower risk (LR) myelodysplastic syndromes (MDS) relapsed after or refractory to erythropoiesis-stimulating agents (ESAs) have limited efficacy and durability; new approaches are needed. Imetelstat is a 13-mer lipid-conjugated oligonucleotide that targets the RNA template of human telomerase and is a competitive inhibitor of telomerase enzymatic activity (Asai et al, Cancer Res 2003; Herbert et al, Oncogene 2005). Preclinical, in vivo xenograft models (Dikmen et al, Cancer Res 2005; Hochreiter et al, Clin Cancer Res 2006) and preliminary clinical data from a pilot study conducted at Mayo Clinic (Tefferi et al, Blood Cancer Journal 2016) supported initiation of a study in TD LR MDS patients. A Phase 2 study of imetelstat, IMerge, demonstrated an 8-week RBC transfusion independence (RBC-TI) rate of 42%, 24-week RBC-TI rate of 29%, and 68% erythroid hematologic improvement (HI-E) rate in 38 heavily TD patients (median prior RBC transfusion burden 8 units / 8 weeks over the 16 weeks pre-study period) with LR MDS. Responses were durable with median duration of 8-week RBC-TI of 85.9 weeks by Kaplan Meier estimates (range 8.0-140.9) (Steensma ASH 2018, Fenaux EHA 2019). These Phase 2 results provided further evidence of potential clinical benefit of imetelstat treatment in TD LR MDS, and supported initiation of a Phase 3 trial. Methods: IMerge is two-part, Phase 2/3 study (ClinicalTrials.gov: NCT02598661). The Phase 2 portion of the study described above is closed for enrollment. The Phase 3 portion of the study is open for enrollment of adult patients with International Prognostic Scoring System (IPSS) low or intermediate-1 risk, non-del(5q) MDS, who are TD, are relapsed after or refractory to ESAs, and have not received treatment with lenalidomide or hypomethylating agents. The study is a randomized (2:1) double-blind, placebo-controlled trial to compare efficacy of imetelstat vs. placebo that will enroll approximately 170 patients and will be conducted at approximately 90 centers in North America, Europe, Asia and Middle East. Imetelstat will be administered as 2-hour IV infusion every 4 weeks at 7.5 mg/kg. The primary endpoint of the study is to assess the rate of RBC-TI lasting ≥8 weeks. Secondary endpoints include safety, rate of RBC-TI ≥24 weeks, time to RBC-TI start, RBC-TI duration, rate of HI-E, the amount and relative change in RBC transfusions, rate of CR or PR, overall survival, progression of MDS, pharmacokinetics and effect of treatment on quality of life. Biomarkers relevant to the mechanism of action of imetelstat will be assessed to demonstrate target inhibition and their association with clinical responses. Cytogenetics and mutation analyses will be performed to evaluate the impact of imetelstat on reduction/depletion of malignant clones leading to disease modification. Disclosures Platzbecker: Novartis: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria. Steensma:Astex: Consultancy; Arrowhead: Equity Ownership; Summer Road: Consultancy; Onconova: Consultancy; Aprea: Research Funding; Pfizer: Consultancy; Stemline: Consultancy; H3 Biosciences: Other: Research funding to institution, not investigator.. Santini:Celgene Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Johnson & Johnson: Honoraria; Acceleron: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Menarini: Membership on an entity's Board of Directors or advisory committees. Germing:Novartis: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Jazz Pharmaceuticals: Honoraria; Amgen: Honoraria. Font:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees. Díez-Campelo:Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Patnaik:Stem Line Pharmaceuticals.: Membership on an entity's Board of Directors or advisory committees. Sherman:Geron Corporation: Employment, Equity Ownership. Dougherty:Geron Corporation: Employment, Equity Ownership. Feller:Geron Corporation: Employment. Sun:Geron Corporation: Employment, Equity Ownership. Wan:Geron Corporation: Employment, Equity Ownership. Huang:Geron Corporation: Employment, Equity Ownership. Rizo:Geron Corporation: Employment, Equity Ownership. Fenaux:Celgene Corporation: Honoraria, Research Funding; Aprea: Research Funding; Astex: Honoraria, Research Funding; Jazz: Honoraria, Research Funding.
Background: Iron deficiency anemia (IDA) is common in cancer patients due to blood loss and inflammation. Intravenous (IV) iron is commonly used in these patients as monotherapy or as an adjunct to erythropoiesis-stimulating agents as many do not tolerate, or adequately respond to oral iron. Over the last decade it has become apparent that hypophosphatemia may occur following some IV iron formulations. While initially considered a transient benign laboratory finding, a growing number of case reports have described treatment-emergent hypophosphatemia following IV iron administration as a safety consideration, especially in patients with normal renal function. Although hypophosphatemia may have clinical consequences, its diagnosis may be missed in the clinic due to initial nonspecific symptomatic presentation e.g., generalized weakness and fatigue. Patients with cancer, already at additional risk for hypophosphatemia for various reasons, including, bone metastasis, bone-modifying agents, and other drugs, might be at a higher risk for hypophosphatemia. Objective: To evaluate the effects of IV iron treatment on the incidence of hypophosphatemia in the subgroup of patients with cancer who participated in a randomized, double-blind Phase 3 clinical trial (NCT02694978) that compared two IV iron preparations for the treatment of adults with IDA of any etiology (excluding dialysis-dependent CKD) and a history of unsatisfactory response to, or intolerance of oral iron. Methods: Randomization was 1:1 to ferumoxytol (FER), administered as two 510 mg doses, or ferric carboxymaltose (FCM), administered as two 750 mg doses both delivered as an IV infusion over at least 15 minutes on days 1 and 8. Serum phosphate and other clinical laboratory values were measured at baseline, days 8 (prior to dose 2), 15, and 35. Data from patients with a recent or coincident diagnosis of cancer were extracted for post-hoc analyses. Within-group changes from baseline in phosphate levels were analyzed with paired t-test; between-group differences were analyzed using ANCOVA adjusted for baseline value. The overall incidence and visit-specific rates of severe hypophosphatemia (CTCAE Grade 3; <2mg/dL) were compared between treatments using Fisher's exact test. Risk factors for incident hypophosphatemia were explored with multivariable logistic regression that included randomized treatment group and baseline clinical factors as candidate predictors. Results: The overall study safety population of 1,997 randomized patients who received any amount of study drug included 153 patients with cancer (78 FCM, 73 FER, 62.1% female; mean age 65.5 ± 13.2 years, mean baseline Hgb 10.5 ± 1.3g/dL, GFR 69.9 ± 32.4 mL/min/m2). Baseline serum phosphate was ≥2.4 mg/dL for all patients in the cancer subgroup, and mean values were similar between treatment groups (FCM 3.74 ± 0.53 and FER 3.86 ± 0.81 mg/dL). Mean serum phosphate level in the FCM group decreased significantly at each time-point compared both to baseline and to the FER group (P<0.0001; Fig. 1), whose mean phosphate remained unchanged. The incidence of treatment-emergent severe hypophosphatemia (<2mg/dL) was higher in the FCM group compared with the FER group, both overall (46.1% vs. 1.4%, p<0.0001) and at each time point (P<0.001; Fig. 2), peaking in frequency at week 2, and remaining at 22.4% for FCM at week 5. In a logistic regression model including factors for renal function, severity of anemia, weight, bisphosphonate use, and baseline phosphate level, the only independent predictors of hypophosphatemia were baseline phosphate level (OR 4.3, 95% CI 1.5 to 12.1, for each 1 mg/dL decrease, P=0.006) and treatment with FCM (OR 120.1, 95% CI 12.2 to 1182.1 vs. FER, P<0.0001). Conclusion: Post hoc analyses of data from a Phase 3 clinical trial showed that mean serum phosphate decreased significantly in anemic cancer patients following FCM, but not FER, starting as soon as 8 days following the first 750mg dose, and did not return to baseline level by the end of the study period. This resulted in hypophosphatemia <2 mg/dL that remained unresolved in some FCM patients through the end of the 5-week study. While this study was not designed to assess the occurrence of symptomatic hypophosphatemia, the persistence of severe hypophosphatemia among FCM patients at the end of the 5-week study period suggests the need for monitoring serum phosphate following FCM usage in clinical practice. Disclosures Boccia: DSI: Speakers Bureau; Genentech: Speakers Bureau; AMAG: Consultancy; Amgen: Speakers Bureau; AstraZeneca: Speakers Bureau; Celgene: Speakers Bureau. Dahl:AMAG Pharmaceuticals, Inc.: Employment, Equity Ownership. Strauss:AMAG Pharmaceuticals, Inc.: Employment, Equity Ownership.
