Roemeling, Reinhard von

Background: Emavusertib (CA-4948) is a novel oral inhibitor of interleukin-1 receptor-associated kinase 4 (IRAK4), which is essential for toll-like receptor (TLR) and interleukin-1 receptor (IL-1R) signaling in B cell proliferation. Additional inhibitory activity against FMS-like tyrosine kinase 3 (FLT3) and CDC-like kinases (CLK1/2/4) is also present in emavusertib. IRAK4 forms a Myddosome complex with MYD88 adaptor protein and drives overactivation ofnuclear factor-kappa B (NF-κB), causing inflammation and tumor growth. Emavusertib has been reported to be well tolerated and active as monotherapy in heavily pretreated patients with relapsed/refractory (R/R) non-Hodgkin lymphoma (NHL) (Nowakowski 2020). Preclinical studies demonstrated that tumor resistance and survival via IRAK4 activation could be delayed or reversed. Emavusertib crossed the blood-brain barrier in a murine PDX model of PCNS lymphoma, blocked the activated IRAK4 pathway, and induced tumor response and prolonged survival (von Roemeling 2022). In combination with Bruton tyrosine kinase (BTK) inhibitors, emavusertib showed in vitro synergy and re-sensitization of resistant cell lines, overcoming BTK resistance (Guidetti 2023a and 2023b). In vivo synergy in B-cell NHL was also demonstrated. Adaptive chemotherapy treatment resistance through IRAK4 upregulation and activation was also described in other disease models (Melgar 2019, Li 2019). This abstract presents preliminary efficacy and safety data of emavusertib + ibrutinib in R/R NHL patients. Aim:Assessment of safety and clinical activity of emavusertib in combination with ibrutinib. Methods: This is an ongoing open-label trial (NCT03328078) of emavusertib as monotherapy and in combination with ibrutinib. Part A1 - completed; dose escalation of emavusertib as monotherapy; the recommended phase 2 dose (RP2D) is 300 mg BID with continuous oral dosing (Nowakowski 2020). Part A2 - completed; dose escalation of emavusertib in combination with ibrutinib at 420 and 560 mg QD (Joffe 2022). Part B - ongoing; an expansion cohort of PCNSL patients with resistance to prior BTK inhibitors for additional safety and efficacy related to exposure: emavusertib at 100 or 200 mg BID + ibrutinib at 560 mg QD in 28-Day cycles. Results:As of 19 July 2023, 18 heavily pretreated NHL (including five PCNSL) patients received emavusertib at 100, 200, or 300 mg BID in combination with full ibrutinib doses per label. Median age was 63.5 years (range 50-92). Median number of prior lines of anti-cancer therapies was 3 (range 1-10). Eleven of 18 patients failed prior BTK inhibitors. Median treatment duration was 95.5 days (21-587 days), suggesting acceptable safety and tolerability. No DLTs were observed at the 200 mg BID dose level, and two reversible DLTs (stomatitis and syncope) were observed at the 300 mg BID dose level. The preliminary efficacy data of 16 evaluable patients in combination with ibrutinib showed 5 CRs (2 MCL, 3 PCNSL) and 1 PR (1 CLL). All 3 PCNSL patients with CR were previously treated with BTK inhibitors. Conclusion: The combination ofemavusertib plus ibrutinib (ema+ibr) is well tolerated with an acceptable long-term safety profile and promising efficacy, showing several objective responses in heavily pretreated and/or BTK inhibitor resistant patients. Emavusertib may have the potential to overcome BTK inhibitor resistance and the combination of ema+ibr has the potential to show increased anti-cancer activity compared to ibrutinib monotherapy.

Abstract BACKGROUND Emavusertib, an oral interleukin-1 receptor-associated kinase 4 (IRAK4) inhibitor, targets toll-like receptor (TLR) and interleukin-1 receptor (IL-1R) signaling pathway in B-cell proliferation. IRAK4 forms a Myddosome complex with MYD88 adaptor protein and drives overactivation of NF-κB, causing inflammation and tumor growth. Emavusertib has been reported to be well tolerated and active as monotherapy in heavily pretreated relapsed/refractory (R/R) non-Hodgkin lymphoma (NHL). In a murine PDX model of primary CNS lymphoma (PCNSL), emavusertib crossed the blood-brain barrier, resulting in tumor response and prolonged survival. In combination with Bruton tyrosine kinase (BTK) inhibitors, emavusertib showed in vivo anti-cancer synergy in B-cell NHL. METHODS This is an ongoing open-label trial (NCT03328078) in patients with R/R NHL. Currently, we are in the dose escalation portion of combination therapy to evaluate safety and efficacy following treatment of emavusertib at dose levels of 200 or 300mg BID with ibrutinib at full prescribed dose. As of May 6th, 2022, 13 patients have been treated with emavusertib+ibrutinib combination therapy. RESULTS Among the 13 patients, two were diagnosed with R/R PCNSL and had several prior lines of anti-cancer therapy. Emavusertib in combination with ibrutinib (560 mg daily) appeared to be well tolerated in these two subjects. One patient experienced Gr3 treatment-related adverse events (thrombocytopenia, muscle weakness, pain). The preliminary efficacy data demonstrated one CR and one SD. The patient who achieved CR after the combination therapy was originally intolerant to high-dose methotrexate based chemoimmunotherapy and did not achieve complete remission after switching to ibrutinib, providing early clinical evidence of CNS penetration and anti-tumor activity of emavusertib. CONCLUSION In R/R PCNSL, these preliminary data suggest that combination therapy has a tolerable safety profile with promising anti-cancer activity and may overcome ibrutinib resistance.

Abstract BACKGROUND PCNSL is an aggressive brain tumor accounting for 3% of all CNS malignancies and is associated with poor prognosis. Standard of care treatment includes induction with high-dose methotrexate based chemoimmunotherapy followed by consolidation with autologous stem cell transplant or whole brain radiation. However, more than half of PCNSL patients cannot tolerate this intensive therapeutic intervention. Novel treatments are urgently needed. Toll-like receptor signaling pathway via MyD88/IRAK-4 signalosome is constitutively active in PCNSL secondary to MYD88 L265P mutation and represents an excellent therapeutic target. Emavusertib (CA-4948) is an oral first-in-class small molecule inhibitor of IRAK-4 that demonstrates clinical activity in patients with systemic Non-Hodgkin’s Lymphoma, however it has not been evaluated in the CNS space. HYPOTHESIS: Emavusertib has anti-tumor activity against preclinical PCNSL. METHODS Using multiparameter immunohistochemistry (IHC) and proteomics analysis, IRAK-1, IRAK-4, and NF-κB pathway activation were examined in patient PCNSL tissues as compared to normal controls. Plasma, cerebrospinal fluid, and brain tissue were assessed via UPLC-MS/MS for emavusertib drug concentration following single oral high dose in a murine model. Survival responses in preclinical PCNSL models were measured in response emavusertib treatment, along with in vivo tumor proliferation and downstream biomarker expression by multi-parameter IHC. RESULTS Our data confirm elevated IRAK-1, IRAK-4, and NF-κB signaling in patient PCNSL. We show that emavusertib can achieve therapeutically relevant concentrations in the brain and CSF. Emavusertib impairs tumor cell proliferation in vitro and in vivo, and shows dose-dependent single-agent activity in preclinical PCNSL models. We confirm decreased ERK1/2, MAPK and NF-κB activation, indicative of downstream IRAK-4 inhibition. CONCLUSIONS Our data supports that emavusertib demonstrates anti-tumor activity in the CNS space, warranting further preclinical and clinical evaluation of this agent for the treatment of PCNSL.

Abstract Background: Central nervous system (CNS) lymphoma, both primary and secondary disease, carries the worst prognosis of all Non-Hodgkin’s lymphoma with a 5 year survival of less than 30% with current therapeutic options. Recent studies have shown constitutive activation of both NF-κB and MAPK signaling pathways in the maintenance and progression of CNS lymphoma. This often coincides with mutations in MYD88. IRAK4 is a serine/threonine kinase that mediates interleukin 1 receptor (IL-1R) and Toll-like receptor (TLR) signaling downstream of MYD88, and is a novel therapeutic target for this disease. CA-4948 is an oral first-in-class small molecule inhibitor of IRAK4 that has demonstrated clinical activity in patients with systemic Non-Hodgkin’s Lymphoma. Our study goal was to evaluate CA-4948 efficacy in a syngeneic preclinical model of primary CNS B cell lymphoma (A20), supporting future clinical investigation of this agent in this difficult to treat disease. Materials and Methods: Plasma, cerebrospinal fluid (CSF), and brain tissue (both naïve and tumor bearing) were assessed for CA-4948 drug concentration following single high-dose oral administration using UPLC-MS/MS. Biomarker expression, including NF-κB and MAPK, was measured in control and CA-4948 treated brain tissue resected from tumor-bearing animals using multi-parameter immunohistochemistry and 3D modeling of cleared tissue. Dose-dependent survival responses were also measured using the A20 preclinical model of primary CNS lymphoma. Results: While brain concentrations of CA-4948 remained low with respect to plasma (~4-5%), therapeutic dose levels were attained in both CSF and brain tissue (>502 nM). No significant difference between naïve and A20 tumor bearing brain tissue was observed, indicating the blood brain barrier remained intact in this model. Biomarker analyses revealed significant downregulation of both MAPK and NF-κB signaling pathways in response to CA-4948, as evidenced by reduced protein levels of phospho-p38Thr180/Tyr182, phospho-ERK1/2Thr202/Tyr204, and phospho-p65Ser536 in both the tumor cells and the tumor microenvironment. Finally, CA-4948 treatment produced a dose-dependent survival response in syngeneic animals harboring CNS A20 tumors. Conclusions: CA-4948 is able to reach therapeutic dose levels in the CNS in a preclinical murine model of CNS lymphoma, producing significant and dose-dependent anti-tumor activity and survival advantage. These data support further evaluation of CA-4948 in clinical investigation and treatment of patients with CNS lymphoma. Citation Format: Christina A. von Roemeling, Bently P. Doonan, Lan Hoang-Minh, Han W. Tun, Elizabeth Martinez, Raul Soikes, Reinhard von Roemeling, Duane A. Mitchell. The IRAK4 inhibitor CA-4948 demonstrates antitumor activity in a preclinical model of CNS lymphoma [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P243.

SummaryFimepinostat (CUDC‐907), a first‐in‐class oral small‐molecule inhibitor of histone deacetylase and phosphatidylinositol 3‐kinase, demonstrated efficacy in a phase 1 study of patients with relapsed/refractory (R/R) diffuse large and high‐grade B‐cell lymphomas (DLBCL/HGBL), particularly those with increased MYC protein expression and/orMYCgene rearrangement/copy number gain (MYC‐altered disease). Therefore, a phase 2 study of fimepinostat was conducted in this patient population with 66 eligible patients treated. The primary end‐point of overall response (OR) rate for patients with MYC‐IHC ≥40% (n = 46) was 15%. Subsequently, exploratory pooled analyses were performed including patients treated on both the phase 1 and 2 studies based upon the presence of MYC‐altered disease as well as a biomarker identified by Virtual Inference of Protein activity by Enriched Regulon analysis (VIPER). For these patients with MYC‐altered disease (n = 63), the overall response (OR) rate was 22% with seven responding patients remaining on treatment for approximately two years or longer, and VIPER yielded a three‐protein biomarker classification with positive and negative predictive values of ≥85%. Prolonged durations of response were achieved by patients with MYC‐altered R/R DLBCL/HGBL treated with single‐agent fimepinostat. Combination therapies and/or biomarker‐based patient selection strategies may lead to higher response rates in future clinical trials.

Introduction: Interleukin-1 receptor-associated kinase 4 (IRAK4) is essential for toll-like receptor (TLR) and interleukin-1 receptor (IL-1R) signaling in immune cells including B lymphocytes. It forms the Myddosome complex with the MYD88 adaptor protein, with IRAK4 being essential for downstream signaling, maximal activation of NFkB with inflammatory and immune response and tumor promotion [Treon 2012; Rhyasen 2015]. CA-4948 is a novel small molecule, oral inhibitor of IRAK4, first-in-class and only suppressor of the TLR pathway currently tested in hematological malignancies. When combined with the BTK inhibitor ibrutinib that blocks parallel BCR signaling and NF-kB activating pathway, it has shown synergy in in-vivo B-cell NHL models, providing strong rationale for clinical evaluation [Booher 2018]. Recent preclinical studies demonstrated the role of IRAK4 activation as a driver of secondary, adaptive tumor resistance and survival mechanisms of hematological and solid tumor malignancies [Melgar 2019] that could be blocked by CA-4948 to delay or reverse resistance. Study Design and Methods: This is a multicenter, open-label trial of oral CA-4948 combined with ibrutinib in adult patients with relapsed or refractory hematologic malignancies. (NCT03328078). It has 2 parts: a dose escalation (Part A2), and expansion basket of 4 cohorts (Part B). Part A2: Is a truncated 3+3 design: CA-4948 starting is 200 mg BID with subsequent escalation to 300 mg BID. Both dose are safe and active against NHL as seen in the nearly completed monotherapy Part A1 of this trial Patients will receive CA-4948 with ibrutinib at the labeled dose for the respective NHL subtype (560 mg or 420 mg) until toxicity or progression. Primary objectives are safety/tolerance (MTD, RP2D); 2nd objectives are pharmacokinetics and preliminary efficacy; exploratory objectives include biomarker correlations (e.g., MYD88-L265P mut, IRAK4 pathway, NFκB inhibition). Part B basket has four cohorts: 1 -MZL, 2 - ABC-DLBCL, 3 - PCNSL, and 4 - NHL with adaptive ibrutinib resistance. Cohorts 1-3 must be BTK-inhibitor naïve. Cohort 4 includes ibrutinib treated NHLs after developing adaptive, secondary resistance. All will receive the combination of ibrutinib and CA-4948. Cohort 4 patients will be allowed a <3 weeks gap since prior ibrutinib therapy. Primary objectives include CR or ORR and DOR compared to (matched) historical controls (closely matched if possible). 2nd objectives include tolerance/safety, PFS, and pop-PK sampling for CA-4948. Exploratory objectives; response correlation with biomarkers including MYD88-L265P or other genetic mutations, gene expressions, cell of origin, IRAK4 signaling, and resistance. Treatment: CA-4948 at RP2D+ibrubinib at labelled doses; 21-day cycles to be repeated in the absence of toxicity or progression. Samples sizes, statistical considerations: Approx. 18 patients in Part A2. In Part B, a Simon 2-Step design will be applied to each cohort. Early stopping rule for futility after approx. 20 patients in Stage 1: full accrual with Stage 2 will add about 25 patients. Successful signal efficacy identification in a cohort may support further expansion or a subsequent controlled trial. The safety population will include all patients in the study who received any test dose. The efficacy population will have a valid baseline and post-baseline disease assessment. Safety assessments include TEAEs, safety labs, vitals, physical exams, PK, and ECGs; efficacy assessments: tumor imaging, para-protein determination, and histo/cyto-morphologic examinations. Part A2 inclusion: Histopathologically confirmed B-cell NHL as per the WHO 2016 classification. Eligible NHL subtypes: FL, MZL, MCL, DLBCL (including extranodal lymphomas of leg, testicle, or other sites, excluding mediastinal lymphoma), CLL/SLL, primary or secondary CNS lymphoma, and WM/LPL. Patients with FL, MCL, MZL, WM/LPL, or CLL/SLL should meet clinical treatment criteria. Part B inclusion: Cohorts 1-3 include patients with MZL, ABC-DLBCL, or PCNSL who are BTK-inhibitor naïve. Cohort 4 will include ibrutinib pre-treated MCL, MZL, CLL/SLL, WM/LPL, ABC-DLBCL, or PCNSL with adaptive resistance. Exclusions for both Parts A2 and B: Significant acute or chronic toxicity from prior anti-cancer therapy that has not resolved to Grade ≤ 1, as determined by NCI CTCAE v 4.03 within 7 days prior to start of study or serious co-morbidities. Disclosures Nowakowski: NanoString: Research Funding; Seattle Genetics: Consultancy; Curis: Consultancy; Kymera: Consultancy; Kite: Consultancy; Celgene/BMS: Consultancy, Research Funding; MorphoSys: Consultancy, Research Funding; Ryvu: Consultancy, Membership on an entity's Board of Directors or advisory committees. Leslie:TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene/BMS: Speakers Bureau; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; KitePharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BeiGene: Speakers Bureau; Pharmacyclics/Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Epizyme: Speakers Bureau; Karyopharm: Speakers Bureau; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees; ADC therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees. Joffe:AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Epizyme: Membership on an entity's Board of Directors or advisory committees. Lunning:Kite: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; TG Therapeutics: Research Funding; Verastem: Consultancy, Honoraria; Acrotech: Consultancy; ADC Therapeutics: Consultancy; Legend: Consultancy; Janssen: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Curis: Research Funding; Gilead: Consultancy, Honoraria; Beigene: Consultancy, Honoraria; Aeratech: Consultancy, Honoraria; Bristol Meyers Squibb: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria. Patel:Adaptive Biotechnologies: Consultancy; Kite: Consultancy; BeiGene: Consultancy; AstraZeneca: Consultancy, Research Funding, Speakers Bureau; Pharmacyclics: Consultancy, Speakers Bureau; Celgene/BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Speakers Bureau; Genentech: Consultancy, Speakers Bureau. Landsburg:Takeda: Research Funding; Triphase: Research Funding; Seattle Genetics: Speakers Bureau; Morphosys: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Curis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees. Fenske:Medical College of Wisconsin: Current Employment. Ramchandren:Merck, Seattle Genetics, Janssen, Genentech: Research Funding; Seattle Genetics, Sandoz-Novartis, Pharmacyclics, an AbbVie Company, Janssen, Bristol-Myers Squibb: Consultancy. Skarbnik:Alexion: Consultancy; Beigene: Speakers Bureau; Verastem: Speakers Bureau; CLL Society: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Kite Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Tun:Bristol-Myers Squibb: Research Funding; Celgene: Research Funding; Mundipharma: Research Funding; Curis: Research Funding; TG Therapeutics: Research Funding; Acrotech: Research Funding; DTRM Biopharma: Research Funding.

Introduction CA-4948 is a novel oral small molecule inhibitor of interleukin-1 receptor-associated kinase 4 (IRAK4). IRAK4 is part of the Myddosome signaling pathway, and is essential for signaling downstream of toll-like receptors (TLR) and the interleukin-1 receptor (IL-1R) family in immune cells including B lymphocytes. . Dysregulated signaling in these pathways is frequently observed in Non-Hodgkin Lymphomas (NHL), particularly in ABC-subtype of Diffuse Large B-Cell Lymphoma (DLBCL) and Waldenström macroglobulinemia (WM)[1]. Furthermore, IRAK4 activation has recently been identified as a driver of an adaptive resistance mechanism of malignancies [2]. CA-4948 is the first clinical candidate targeting IRAK4 to be evaluated in cancer patients. Here we present Phase I results of CA-4948 in patients with relapsed/refractory hematologic malignancies. Method CA-4948-101 is a phase I trial dose escalation trial with a 3 + 3 design. Seven dosing cohorts were assessed including 50 and 100 mg daily (QD), and 50, 100, 200, 300, or 400 mg twice daily (BID) continuous oral monotherapy in 21-day cycles. Objectives included safety and tolerance (primary), pharmacokinetic (PK), pharmacodynamics (PD) and early efficacy (secondary), and biomarker correlations (exploratory). As of July 2020, 30 patients with relapsed or refractory, NHL have been enrolled, including DLBCL (n=14), FL (n=6), transformed HGBL (n=1), WM (n=3), LPL (n=2), MZL (n=2) and MCL (n=2). Median age is 68.5 (range 50 - 87; 5 female / 25 male). Median number of prior treatments is 4 (range 1 - 8, incl. 5 CAR-T-cell or ASCT treatments). Results CA-4948 has been generally well tolerated. Eight patients were exposed at the highest dose level of 400 mg BID: 2 of 5 DLT-evaluable patients had Grade 3 rhabdomyolysis (DLTs), without complications and reversible after treatment interruption and hydration / analgesic treatment - both subsequently continued treatment at lower doses of 200 or 300 mg BID, respectively. Six patients have tolerated 300 mg BID well without DLT. Most non-hematologic TEAEs were Grade 1 or 2 and manageable, including diarrhea, vomiting, fatigue, dyspnea, and myalgia. Hematologic TEAEs including neutropenia, anemia, thrombocytopenia was mild/moderate and without complications. There were only 4 Grade 3 combined episodes in 18 patients at dose levels ranging between 200 and 400 mg BID without complications (Table 1). Drug discontinuation occurred in only 3 cases for rash, fatigue, and asymptomatic amylase/lipase elevation at lower dose levels. No toxic deaths occurred. Favorable and predictable PK characteristics included rapid absorption with Tmax at 2-3 hours, T1/2 of 6 hours (supporting bid dosing), moderate accumulation, and dose-proportional increases in exposure. Dose proportional PD changes were shown for inflammatory cytokine reductions. Treatment duration ranged between 15 days and 19+ months with sustained disease control. Eight of 28 evaluable patients experienced overall tumor burden decreases of ≥20% from baseline - more at higher doses (Table 2). A WM patient with 6 prior lines of treatment, sustained PR underwent intra-patient dose escalation and had a dose/response relationship and very good treatment tolerance (Figure 1). The median duration at doses of 200 or 300 mg bid was >6 months (range 1-19+; including 3 cases of 11, 14, and 19+ mo.). Downstream pharmacodynamic markers of IRAK4 and molecular characteristics including cell-of-origin will be presented. Conclusion CA-4948 demonstrates good safety profile, desirable pharmacokinetic properties, and preliminary clinical activity. Enrollment is ongoing to support the anticipated RP2D of 300 mg bid. These encouraging results provide clinical validation of IRAK4 as a viable, novel therapeutic target in B-cell malignancies will lead to clinical combinations with synergistic drugs including BTK or BCL2 inhibitors [3] in patients with advanced hematological malignancies. Clinical trial: NCT03328078. References: 1. Treon, S. P. et al., 2012. N Engl J Med, 367: 826-33 2. Melgar, K. et al., 2019. Sci Transl Med, 11: eaaw8828 3. Booher R, Grayson D., 2019. Waldenstrom Roadmap Symposium, www.Curis.com Disclosures Nowakowski: Curis: Consultancy; MorphoSys: Consultancy, Research Funding; Celgene/BMS: Consultancy, Research Funding; Kite: Consultancy; Ryvu: Consultancy, Membership on an entity's Board of Directors or advisory committees; NanoString: Research Funding; Kymera: Consultancy; Seattle Genetics: Consultancy. Leslie:TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; ADC therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Honoraria, Speakers Bureau; Epizyme: Honoraria, Speakers Bureau; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BeiGene: Honoraria, Speakers Bureau; KitePharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Speakers Bureau; Celgene: Speakers Bureau; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Younes:Curis: Consultancy; Daiichi Sankyo: Consultancy; HCM: Consultancy; Epizyme: Consultancy; Takeda: Consultancy; Novartis: Consultancy; BioPath: Consultancy; BMS: Consultancy; Janssen: Consultancy; AstraZeneca: Current Employment. Lunning:Gilead: Consultancy, Honoraria; Curis: Research Funding; Beigene: Consultancy, Honoraria; Aeratech: Consultancy, Honoraria; Bristol Meyers Squibb: Consultancy, Honoraria, Research Funding; Kite: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; AstraZeneca: Consultancy, Honoraria; Legend: Consultancy; ADC Therapeutics: Consultancy; Acrotech: Consultancy; Verastem: Consultancy, Honoraria; TG Therapeutics: Research Funding. Patel:Celgene/BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Consultancy; BeiGene: Consultancy; Pharmacyclics: Consultancy, Speakers Bureau; AstraZeneca: Consultancy, Research Funding, Speakers Bureau; Kite: Consultancy; Genentech: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau. Landsburg:Takeda: Research Funding; Seattle Genetics: Speakers Bureau; Morphosys: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Curis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Triphase: Research Funding. Tun:Bristol-Myers Squibb: Research Funding; Celgene: Research Funding; Mundipharma: Research Funding; Curis: Research Funding; TG Therapeutics: Research Funding; Acrotech: Research Funding; DTRM Biopharma: Research Funding.

Abstract Background: Stage IVC (metastatic) anaplastic thyroid cancer (ATC) has a median overall survival (OS) of only 1.9 months. Single agent paclitaxel has modest activity in ATC. In pre-clinical studies, CS-7017 inhibited ATC proliferation through a novel mechanism–activation of PPAR-γ, followed by sequential upregulation of RhoB, then p21. Moreover, CS-7017 augmented the proapoptotic effects of paclitaxel. Based on these results, a multicenter study was conducted to determine if CS-7017+paclitaxel might prove safe and effective in advanced ATC. Design: A Phase 1 study was conducted to determine the Phase 2 dose. In Phase 1, patients received CS-7017 orally BID for one week (run-in phase), followed by a 3 h iv infusion of paclitaxel (175 mg/m2) every 3 weeks in combination with BID CS-7017. CS-7017 doses were escalated (0.15, 0.3, or 0.5 mg). Tissue biopsies were obtained at baseline and at one and three weeks for immunohistochemistry of PPAR-γ responsive proteins; serum CS-7017 PK studies were also performed. Results: Nineteen patients were enrolled, but 4 were not dosed (3 due to progression, 1 ineligible). Seven participated in CS-7017 dose levels 1a/1b (0.15 mg BID), six in dose level 2 (0.3 mg BID), and two in dose level 3 (run-in phase only–0.5 mg BID). Demographics: Of the 15 treated patients, 10 (67%) were women. Median age was 59 years (range: 43-82) Efficacy: Of 15 patients receiving drug, one had a confirmed partial response (PR) lasting from Day 69 to Day 175, and eight had stable disease (SD) as their best response. Median Time to Progression in 7 patients at Dose Level 1 was 49 days, but 70 days in Dose Level 2 (43% prolongation); corresponding median survival was 99 (0.15 mg BID) vs. 140 days (0.3 mg BID, 42% increase). Median peak CS-7017 blood level was 8.6 ng/mL (range: 5.1 to 13.7) for Level 1 and 22.0 ng/mL (17.0 to 31.5) for Dose Level 2. Adverse Events: Ten patients had AEs ≥ Grade 3, with two (anemia and localized edema) related to CS-7017. Thirteen events of fluid retention/edema were reported in 8 patients, with only 2 events of CTCAE grade ≥ 3. Eight patients had ≥ one SAE, with one (anemia) due to CS-7017. One SAE (anaphylactic reaction) was related to paclitaxel. No dose limiting toxicity was observed. Immunohistochemistry: Biopsies were available on 7 patients. PPAR-γ, RXR-α, RhoB were present in all; Angiopoietin-like 4 was induced by CS-7017. Conclusions: Combination therapy with CS-7017 and paclitaxel was tolerated and has biologic activity in patients with metastatic anaplastic thyroid carcinoma, with initial exploratory data suggesting a dose-dependent improvement in time to progression and survival in response to escalating CS-7017 dosage. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1278. doi:10.1158/1538-7445.AM2011-1278