Heise, Carla

17502 Background: CHIR-258 is an orally active small molecule receptor tyrosine kinase (RTK) inhibitor which has potent activity against multiple RTKs involved in tumor growth and angiogenesis (IC50 ≤13 nM for FGFR, VEGFR, PDGFR, C-KIT, and FLT3). Approximately 15% of newly diagnosed MM patients harbor a t(4;14) translocation, which results in ectopic expression of FGFR3 and MMSET and is associated with poor treatment outcome [0]and reduced survival. CHIR-258 inhibits proliferation and induces apoptosis in FGFR3-expressing MM tumor xenografts as well as FGFR3-expressing primary MM cells (Trudel et al, Blood 2005). CHIR-258 was synergistic with dexamethasone (dex) in vitro. Methods: CHIR-258 was administered once daily in a dose-escalating phase 1 study to patients with relapsed/refractory MM. Drug tolerability and safety, pharmacokinetics (PK) and pharmacodynamics (PD) were assessed. Results: as of December 2005, 9 total pts have been treated (50, 100, and 200mg qd cohorts) [6M, 3F; median age: 58 (range: 44–68), median of 3 prior therapies(range:1–7)]. Prior tx: 9/9 pts-thalidomide; 8/9 -Velcade; 8/9-transplant; 8/9- had progressed through dex. 4 of 9 pts treated were FGFR3+ and 4 pts remain on study (3 are FGFR3+). No CR or PR have been observed; stable disease has been noted. CHIR-258 has been generally well tolerated, and most drug related AEs were CTC grade 1 or 2, including: headache, dysgeusia, fatigue and anorexia. No neuropathy. One DLT has been observed to date: neutropenia (200mg cohort). Five pts had dex added to CHIR-258 of which 3 are ongoing (all FGFR3+). FGFR3+ pts receiving dex and CHIR-258 have a greater decline in urine and serum paraproteins (pp) vs CHIR-258 alone. Plasma exposure and Cmax increased proportionally across the doses. Conclusions: CHIR-258 is a novel inhibitor of RTKs involved in MM growth and proliferation. FGFR3+ pts have a more marked reduction in pp than FGFR3- pts. CHIR-258 has generally been well tolerated and further accrual continues. [Table: see text]

Abstract Introduction Patients with mantle cell lymphoma (MCL) typically respond to initial therapy and almost inevitably relapse with frequent chemoresistance over time and poor outcome. Multiple phase II studies have established the efficacy and safety of lenalidomide, an immunomodulatory agent with tumoricidal and antiproliferative properties, in relapsed/refractory MCL. The prospective phase II multicenter MCL-001 “EMERGE” study led to FDA approval of lenalidomide for patients with relapsed/refractory MCL after 2 prior treatments, that included bortezomib. The activity of lenalidomide was seen regardless of MIPI, number of prior therapies, prior high dose therapy, bulky disease or high tumor burden. One of the most established prognostic factors in MCL is the proliferation index Ki67 (MIB1), now confirmed both in standard and dose-intensive high-dose therapy strategies. We present here longer follow-up of efficacy and safety from the MCL-001 study in patients relapsed/refractory to bortezomib and the potential relationship between Ki-67 and efficacy outcomes. Methods Patients with heavily pretreated MCL, that included prior bortezomib, received lenalidomide 25 mg/day PO, days 1-21 in 28-day cycles until disease progression or intolerability. Primary study endpoints were overall response rate (ORR) and duration of response (DOR); secondary endpoints included complete response (CR), time to response (TTR), progression-free survival (PFS), overall survival (OS), and safety. Response rates and time-to-event data were analyzed by independent central reviewers per modified IWG criteria and Kaplan-Meier estimates respectively (data cut-off March 20, 2013). Ki-67 was examined as an exploratory endpoint by immunohistochemistry for 81/134 patients (60%) either performed on biopsy samples for 24 patients, or based on the Ki-67 scores reported in local pathology reports for 57 patients. Results Median age for the enrolled intent-to-treat patient population (N=134) was 67 years (range, 43-83; 63% ≥65 years). The median number of previous therapies was 4 (range, 2-10; 78% received ≥3), 93% stage III/IV, and 72% were <6 months from last prior treatment. At a median follow-up of 13.2 months, the ORR was 28% (CR/CRu 8%), with a median DOR of 16.6 months (95% CI, 9.2-26.7; median not reached in patients with CR/CRu) by central review. Median TTR was 2.3 months (95% CI, 1.7-13.1), with a median time to CR/CRu of 4.1 months (95% CI, 1.9-13.2). Median PFS was 4.0 months (95% CI, 3.6-6.9), and median OS was 20.9 months (95% CI, 13.7-24.4). The average dose intensity of lenalidomide was 20 mg/day, for a median duration of 94.5 days (range, 1-1,256). Dose reductions or interruptions due to adverse events (AEs) occurred in 40% and 58% of patients, respectively. Neutropenia (44%), thrombocytopenia (28%), and anemia (11%) were the most common treatment-related grade 3/4 AEs. Ki-67 results were available in 81/134 patients, and efficacy data were categorized using 30% and 50% cut-off thresholds for Ki-67 expression (Table 1). Although patient numbers were limited, the ORR was similar in both lower and higher Ki-67 group, but those with lower Ki-67 levels demonstrated better CR rates, DOR and survival outcomes compared with patients with elevated Ki-67. Conclusions Single-agent lenalidomide in heavily pretreated patients with relapsed/refractory MCL post-bortezomib showed durable long-term efficacy with a consistent safety profile. Consistent with what is reported in the literature, high Ki-67 is associated with poor outcome in our cohort with shorter OS. Though based on retrospective evaluation and subsets of patients, the ORR to lenalidomide was similar in both low and high Ki-67 groups, suggesting lenalidomide can be active in patients expressing high levels of Ki67. Prospective studies are needed to confirm these findings. Disclosures: Goy: Celgene: Consultancy, Research Funding, Speakers Bureau. Off Label Use: This is a phase 2 clinical study of safety and efficacy for lenalidomide in patients with MCL. Williams:Celgene: Consultancy, Membership on an entity’s Board of Directors or advisory committees, Research Funding. Drach:Celgene: Honoraria. Ramchandren:Celgene: Research Funding. Zhang:Celgene: Employment. Cicero:Celgene: Employment. Fu:Celgene: Employment. Heise:Celgene: Employment, Equity Ownership. Witzig:Celgene: Research Funding.

Abstract Overexpression of fibroblast growth factor receptor 3 (FGFR3) is a hallmark of t(4;14) multiple myeloma (MM). To dissect the mechanism of FGFR3 oncogenesis in MM, we used 3 FGFR selective kinase inhibitors—CHIR258, PD173074, and SU5402—and FGFR3-specific siRNA to modulate FGFR3 activity. Conversely, the ligand FGF was used to stimulate FGFR3 function in human MM cells. The transcriptional response to FGFR3 modification was recorded, and gene expression changes common to all 5 modifiers were documented. Ten genes were commonly regulated. Macrophage inflammatory protein-1 alpha (MIP-1α) was the single most differentially altered gene. MIP-1 α promoter function, gene expression, and protein secretion were each down-regulated following inhibition of FGFR3 signaling. Down-regulation of MIP-1 α was not, however, observed following FGFR3 inhibition in MM cells with RAS mutations implicating RAS-MAPK in MIP-1 α regulation. As confirmation, inhibition of ERK1 also down-regulated MIP-1 α in FGFR3 inhibitor-resistant cells harboring RAS mutations. MIP-1 α is implicated in the survival and proliferation of MM cells and the pathogenesis of MM bone disease. Our observation is the first to directly link an initiating IgH translocation not only to MM-cell growth and survival but also to the disease-associated bone disease.