Gualberto, Antonio

PURPOSEMutations in the HRAS (m HRAS) proto-oncogene occur in 4%-8% of patients with recurrent and/or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC). Tipifarnib is a farnesyltransferase inhibitor that disrupts HRAS function. We evaluated the efficacy of tipifarnib in patients with R/M m HRAS HNSCC.METHODSWe enrolled 30 patients with R/M HNSCC in a single-arm, open-label phase II trial of tipifarnib for m HRAS malignancies; one additional patient was treated on an expanded access program. After an ad hoc analysis of the first 16 patients with HNSCC with m HRAS variant allele frequency (VAF) data, enrollment was limited to those with a m HRAS VAF of ≥ 20% (high VAF). The primary end point was objective response rate. Secondary end points included assessing safety and tolerability. Patients received tipifarnib 600 or 900 mg orally twice daily on days 1-7 and 15-21 of 28-day cycles.RESULTSOf the 22 patients with HNSCC with high VAF, 20 were evaluable for response at the time of data cutoff. Objective response rate for evaluable patients with high-VAF HNSCC was 55% (95% CI, 31.5 to 76.9). Median progression-free survival on tipifarnib was 5.6 months (95% CI, 3.6 to 16.4) versus 3.6 months (95% CI, 1.3 to 5.2) on last prior therapy. Median overall survival was 15.4 months (95% CI, 7.0 to 29.7). The most frequent treatment-emergent adverse events among the 30 patients with HNSCC were anemia (37%) and lymphopenia (13%).CONCLUSIONTipifarnib demonstrated encouraging efficacy in patients with R/M HNSCC with HRAS mutations for whom limited therapeutic options exist ( NCT02383927 ).

8072 Background: Figitumumab (CP-751,871) is a fully human, IgG2monoclonal antibody against the insulin-like growth factor type I receptor (IGF-IR). We reported in a randomized phase II study (ASCO 2008), preliminary evidence of high activity of the combination of paclitaxel (T), carboplatin (C) and figitumumab (F) in advanced treatment-naïve NSCLC of squamous cell histology (n=11 pts). A single arm trial extension cohort was conducted to confirm those findings. Methods: Fifty-six pts with non-adenocarcinoma NSCLC were enrolled. Pts received T (200 mg/m2), C (AUC of 6) and F (20 mg/kg) q3weeks for up to 6 cycles; pts with response (PR) or stable disease were eligible to continue F as single agent until disease progression. Statistical hypotheses were 30% (null) versus 50% (response of interest). Protein expression of the IGF-IR in core tumor biopsies was quantified using automated quantitative analysis (AQUA) technology. Results: Pts were 72% male, 28% >70 years old and 91% stage IV. Median number of treatment cycles was 4, with 46% of pts receiving single agent F beyond cycle 4. TCF was well tolerated. The most common all-causality grade 3, 4 CTCAE adverse events were neutropenia (21%), hyperglycemia (14%) and fatigue (14%). Hyperglycemia adverse events almost always occurred within the first treatment cycle and were manageable with standard measures. Responses in squamous pts are currently 25 out of 40 pts according to RECIST, with final response assessment still pending for 7 additional pts (≥53%, p<0.001). One complete response and 7 striking PRs (50–80% tumor size reduction at cycle 2) were observed. Tumor size reductions with F maintenance treatment were also seen in 2 pts. Median progression free survival has not been yet reached at 4 months follow up. A trend (p=0.1) for higher IGF-IR expression in patients responding to TCF was observed in a small data set (n=12). Median tumor IGF-IR expression in pts responding to TCF therapy and non-responders were respectively 6287 and 4131 AQUA scores. Analysis of IGF-IR and other members of the IGF-IR pathway continues. Conclusions: These data further support the activity of figitumumab combination therapy in pts with squamous NSCLC. [Table: see text]

Abstract Background: This Phase 2 study (NCT02383927) is a multi-institutional, open-label trial to determine the efficacy and safety of tipifarnib in patients (pts) with locally advanced/unresectable and/or metastatic solid tumors that carry HRAS missense mutations. HRAS is a proto-oncogene that is overexpressed and mutated in head and neck squamous cell carcinomas (HNSCC) and other SCCs. Tipifarnib is a potent and highly selective inhibitor of farnesyltransferase, a critical enzyme for HRAS activity. Methods: Pts received tipifarnib at a starting dose of 600 – 900 mg orally twice daily on days 1-7 and 15-21 of 28-day cycles. Disease assessments were conducted according to RECIST v1.1 criteria. Null hypothesis and objective response of interest were respectively 10% and 30%. Prior to its completion, this study met its primary objective and, based on preliminary efficacy results (Ho, et. al, ESMO 2018), was amended to continue enrolling only pts with HNSCC (Cohort 2) and other SCC tumors (Cohort 3) carrying HRAS missense mutations at a high variant allele frequency (VAF &gt;35% or ≥20% if baseline serum albumin is &gt;3.5 g/dL). Results: As of May 1, 2019, 23 pts with HNSCC and 10 pts with tumors with other SCC histologies have been treated with tipifarnib. Pts had relapsed/refractory disease with a median of 2 prior regimens. Of note, no objective partial responses were observed on their last therapy prior to study entry, including platinum, immunotherapy and cetuximab +/- chemotherapy. In 15 HNSCC pts meeting the HRAS mutation high VAF inclusion criteria, a 53% overall response rate (ORR) was observed, with 8 confirmed partial responses (PR) and 5 disease stabilizations (SD). Two pts await first on-study tumor response assessment. Overall median progression free survival (PFS) was 5.4 mos (95% CI 4.5 to 19.5 mos, N=15); 19 mos (95% CI 5.3 to 19.5 mos) for pts experiencing a PR and 4.5 mos (95% CI 1.6 to 5.4 mos) for those experiencing SD. Median PFS on last prior therapy was 3.2 mos. All pts had at least 1 treatment-emergent adverse event (TEAE). The most frequently observed drug-related Grade &gt;3 TEAEs occurring in ≥10% pts were blood and lymphatic system disorders, gastrointestinal disorders and renal disorders. Conclusions: Encouraging activity of tipifarnib was observed in HRAS mutant HNSCC. Based on these data, a pivotal study (AIM-HN and SEQ-HN Study, NCT03719690) evaluating the efficacy of this agent in HRAS mutant HNSCC (AIM-HN) and the impact of HRAS mutations on first line therapy of HNSCC (SEQ-HN) has been initiated. Citation Format: Alan Ho, Irene Brana, Robert Haddad, Jessica Bauman, Keith Bible, Laurence Faugeras, Sjoukje Oosting, Deborah J Wong, Myung-Ju Ahn, Valentina Boni, Caroline Even, Jerome Fayette, Maria Jose Flor, Kevin Harrington, Sung-Bae Kim, Lisa Licitra, Ioanna Nixon, Nabil F Saba, Cyrus Sayehli, Pol Specenier, Francis Worden, Binaifer Balsara, Jeanne Britt, Vishnu Mishra, Catherine Scholz, Antonio Gualberto. Preliminary results from a phase 2 trial of tipifarnib in squamous cell carcinomas (SCCs) with HRAS mutations [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr PR08. doi:10.1158/1535-7163.TARG-19-PR08

7609 Background: Multiple lines of evidence indicate that the Insulin Like Growth Factor 1 Receptor (IGF-1R) plays a key role in the progression of multiple myeloma (MM). IGF-1 is a growth factor for MM cells. It promotes survival to the cytotoxic effects of chemotherapy in animal models of MM and its blood levels has been shown to correlate with those of paraprotein in MM patients. CP-751,871, a fully human monoclonal antibody, is a highly specific and potent inhibitor of the autophosphorylation of IGF-1R. Methods: Based on its mechanism of action and the potential relevance of IGF-1R in MM, a Phase 1 First-in-Human dose escalation study was initiated with the objective to define the safety and tolerability, and to characterize the pharmacokinetic and pharmacodynamic properties of CP-751,871 in this patient population. Patient’s eligibility included previously treated multiple myeloma in relapse or refractory phase and/or less than complete remission following autologous stem cell transplant or tandem transplant. Results: Following informed consent and screening, 10 dose-escalation cohorts of patients received from 0.025 to 10 mg/kg of CP-751,871 by iv infusion on Day 1 of 4-week cycles. In patients with a suboptimal response to CP-751,871 alone, oral dexamethasone was added to the treatment regimen. Patients received up to 14 cycles of CP-751,871 therapy, alone or in combination with dexamethasone. No dose limiting toxicities have been identified to date. Plasma CP-751,871 exposure increases with dose, and the pharmacokinetic characteristics are consistent with target-mediated disposition. Pharmacodynamic measurements indicate complete target saturation by CP-751,871 for the complete length of the dosing period. One near CR and 2 PR in combination with dexamethasone have been reported. Conclusions: These data indicate that CP-751,871 is well tolerated and may constitute a therapeutic approach for patients with multiple myeloma. [Table: see text]

3587 Background: The Insulin like Growth Factor I receptor (IGF-IR), a tyrosine kinase, is widely expressed in human tissues. IGF- IR and its ligands (IGF-I and IGF-II) are expressed by many human cancers (e.g., breast, prostate, colorectal and non-small cell lung). Binding of the ligands to the IGF-IR activates key cellular signaling pathways important for stimulating cellular proliferation and inhibiting apoptosis. IGF- I and IGF-II are present in the circulation, but also locally expressed in neoplastic tissue. Bioavailability of these ligands is regulated by a family of IGF binding proteins (IGFBPs1–6). CP-751,871, a fully human monoclonal antibody, is a highly specific and potent inhibitor of IGF-IR activation. In vitro experiments show that binding of CP 751,871 to IGF-IR induces receptor internalization and degradation. This antibody has been shown to have antineoplastic activity using both in vivo and in vitro pre-clinical models. Methods: Blood samples were collected for characterization of the pharmacokinetic and pharmacodynamic properties of CP-751,871 in phase 1 trials of this agent given to cancer patients either alone or in combination with chemotherapy. The endpoints assessed included among others: CP-751,871 plasma concentrations, total and free IGF-I, IGFBP-3, soluble IGF-IR and IGF-IR expression on granulocytes and tumor cells. Results: CP 751,871 exposure increased with dose over the 800-fold dose range investigated. Pharmacokinetic profiles were consistent with target-mediated disposition. A dose-dependent downregulation of soluble IGF-IR serum concentration and IGF-IR expression was observed, with sustained inhibition for the entire dosing period (3–4 week cycles) observed at doses ≥ 1.5 mg/kg. As predicted for an agent that interferes with IGF-I action, IGF-I and IGFBP-3 serum levels were up-regulated in a similar dose-dependent manner. Conclusions: The pharmacodynamic endpoints of clinical trials provide evidence that CP-751,871 targets IGF-IR in granulocytes, tumor cells and tissues involved in regulation of the growth hormone -IGF-I axis. These data provide proof of principle for the use of CP-751,871 as a first-in-class therapeutic approach to inhibit the IGF-IR pathway in cancer patients. No significant financial relationships to disclose.

3586 Background: The insulin-like growth factor 1 receptor (IGF-IR), a tyrosine kinase, and its ligands (IGF-I & -2) are upregulated in many human tumors (e.g., breast, prostate, colon and non-small cell lung cancer) and enhance proliferative and prosurvival signaling. Inhibition of IGF-IR activation in tumor models suppresses tumor growth and increases tumor sensitivity to chemotherapy, supporting the development of agents targeting IGF-IR. CP-751,871 is a potent, highly specific, fully humanized, monoclonal antibody that inhibits IGF-IR autophosphorylation and induces receptor internalization. Methods: A Phase I dose escalation study was initiated to define the safety and tolerability, and to characterize the pharmacokinetic properties of CP-751,871 in patients with advanced solid tumors refractory to standard therapies. Results: Following informed consent and screening, a total of 24 patients with refractory solid tumors (e.g. colorectal, NSCLC, sarcoma and prostate cancer; 1–6 previous regimens) were enrolled. Patients received 3 to 20 mg/kg of CP-751,871 by IV infusion on Day 1 of 3-week cycles in four dose-escalation cohorts of 3 patients. No dose limiting toxicities were identified and the maximum feasible dose (MFD) cohort of 20 mg/kg was extended with 12 additional patients. No higher than grade 3 CTCAE v3.0 toxicities, attributed to study drug, have been so far reported. Grade 3 toxicities, all reported in patients dosed with 20 mg/kg of CP-751,871, are increased GGT (4%) and fatigue (4%). Grade 2 toxicities include: anorexia (7%), diarrhea (7%), increased GGT (4%), hyperglycemia (4%), fatigue (4%), increased urinary frequency (4%), nausea (4%), increased ALT (4%) and increased AST (4%). Pharmacokinetic analysis is currently ongoing. No objective responses were observed. At the MFD, patients received a median of 4 cycles (1–16). Three patients were stable for > 6 months and one patient, currently at cycle 16, remains on study. An additional cohort of 12 adrenocortical cancer patients is under evaluation. Conclusions: These data indicate that CP-751,871 is safe and well tolerated. Due to its good safety profile, CP-751,871 may constitute a suitable targeted agent to use in combination with approved therapies in multiple tumor types. No significant financial relationships to disclose.

3507 Purpose: To detect IGF-1R on circulating tumor cells (CTCs) as a biomarker in the clinical development of a monoclonal human antibody, CP-751,871, targeting IGF-1R. Experimental Design: An automated sample preparation and analysis system for enumerating CTCs (Celltracks) was adapted for detecting IGF-1R positive CTCs with a diagnostic antibody targeting a different IGF-1R epitope to CP-751,871. This assay was utilized in three phase I trials of CP-751,871 as a single agent or with chemotherapy and was validated using cell lines and blood samples from healthy volunteers and patients with metastatic carcinoma. Results: There was no interference between the analytical and therapeutic antibodies. CP-751,871 was well tolerated as a single agent, and in combination with docetaxel or carboplatin and paclitaxel, at doses ranging from 0.05 mg/kg to 20 mg/kg. Eighty patients were enrolled on phase 1 studies of CP-751,871, with 47 (59%) patients having CTCs detected during the study. Prior to treatment 26 patients (33%) had CTCs, with 23 having detectable IGF-1R positive CTCs. CP-751,871 alone, and CP-751,871 with cytotoxic chemotherapy, decreased CTCs and IGF-1R positive CTCs; these increased towards the end of the 21-day cycle in some patients, falling again with retreatment. CTCs were commonest in advanced hormone refractory prostate cancer (11/20). Detectable IGF-1R expression on CTCs before treatment with CP-751,871 and docetaxel was associated with a higher frequency of PSA decline by more than 50% (6/10 vs 2/8 patients). A relationship was observed between sustained falls in CTCs counts and PSA declines by more than 50%. Conclusions: IGF-1R expression is detectable by immunofluorescence on CTCs. These data support the further evaluation of CTCs in pharmacodynamic studies and patient selection, particularly in advanced prostate cancer. No significant financial relationships to disclose.

Background Tipifarnib is a potent and selective inhibitor of the enzyme farnesyltransferase (FT). FT catalyzes post-translational attachment of farnesyl groups required for localization of signaling molecules to the inner cell membrane. CXCL12 is a ligand for CXCR4 that is essential for T cell homing to lymphoid organs and the bone marrow, and for the maintenance of immune cell progenitors. We have previously shown that FT inhibition by tipifarnib downregulates CXCL12 secretion. Herein we report preliminary efficacy, safety and biomarker data from a Phase 2 study of tipifarnib in angioimmunoblastic T-cell lymphoma (AITL) and CXCL12+ peripheral T-cell lymphoma (PTCL) patients (pts). Methods This Phase 2 study (NCT02464228) is a multi-institutional, single-arm, open-label trial initially designed as a two-stage (11+7 pts) design to determine the efficacy, safety and biomarkers of tipifarnib in pts with relapsed/refractory (R/R) PTCL age &gt;/=18 years and a performance status of 0-2. Based on initial findings, the study was amended to include a cohort of AITL (n=12) and PTCL (n=12) pts with the CXCL12 rs2839695 A/A genotype (wt CXCL12 3'UTR cohort). Pts received tipifarnib 300 mg administered orally twice daily on days 1-21 of 28-day treatment cycles until progression of disease (PD) or unacceptable toxicity. The primary endpoint of the study is overall response rate (ORR). Tumor Whole Exon Sequencing (WES) was generated by NGS and gene expression data generated by RNA Seq. Ancillary studies also investigated the prognostic value of CXCL12 expression in pts who received standard of care treatment. Results As of 24 May 2019, 50 PTCL pts (23 AITL, 25 PTCL-NOS, 1 ALK- ALCL, 1 gamma-delta TCL) have been treated with tipifarnib, 19 pts in stages 1 and 2, and 31 pts in the ongoing AITL histology and wt CXCL12 3'UTR cohorts. Median number of prior treatment regimens was 3; 19 pts had a prior stem cell transplant. All pts (n=48 with available safety data) had at least one treatment-emergent adverse event (TEAE); 42 (88%) had at least 1 study drug-related TEAE and 13 (27%) at least 1 drug related SAE. The most frequently observed drug-related TEAEs of Grade &gt;3 occurring in 10% or more of pts were blood and lymphatic system disorders, including neutropenia (40%), thrombocytopenia (33%), leukopenia (25%), anemia and febrile neutropenia (19% each). There have been 14 deaths on study; one related to study drug (lung infection). Of 18 evaluable pts enrolled in Stages 1 and 2 of the trial, 3 partial responses (PR), 2 of them in pts with AITL histology, and 5 best responses of stable disease (SD) were observed. In the AITL cohort (11 evaluable of 16 pts enrolled), a 45% ORR and 73% clinical benefit rate (CBR; 3 CR, 2 PR and 3 SD) was observed. In the wt CXCL12 3'UTR cohort (n=12 evaluable pts), a 42% ORR was observed (3 CR, 2 PR), with 2 of the 3 CRs observed in patients of AITL histology (n=4). A total of 23 AITL subjects were enrolled in the overall study of whom 16 had WES data. A strong association with the activity of tipifarnib was observed in 8 of the 16 (50%) carrying KIR3DL2 gene variants C336R/Q386E: 50% CR rate, 75% ORR, 100% clinical benefit rate. These tumors expressed also very low levels of CXCL5, a ligand for CXCR2, that may mediate resistance to tipifarnib. High Allele Frequency of KIR3DL2 variants predicted CR to tipifarnib treatment (ROC AUC=0.94, p&lt;0.0001) and AITL patients carrying KIR3DL2 gene variants experienced a better outcome with tipifarnib treatment than with prior SOC treatment. While AITL tumors expressed high levels of CXCL12 and responded to tipifarnib, a trend for poor prognosis (22 vs 40 months median OS from diagnosis, HR=1.8, p=0.09) was observed in a series of 50 PTCL subjects treated with SOC therapy. Fifty percent of AITL and 35% of non-AITL samples overexpressed CXCL12. Conclusion The AITL and wt CXCL12 3'UTR cohorts met pre-specified statistical hypotheses supporting proof-of-concept for tipifarnib in PTCL. AITL histology, KIR3DL2 and CXCL12 genotype provided robust tools for the selection/stratification of PTCL subjects treated with tipifarnib. Extended enrollment of AITL patients continues and an update on enrollment and outcomes will be provided at the time of the presentation. Disclosures Sokol: EUSA: Consultancy. Foss:Mallinckrodt: Consultancy; Eisai: Consultancy; Spectrum: Other: fees for non-CME/CE services ; Acrotech: Consultancy; Seattle Genetics: Consultancy, Other: fees for non-CME/CE services ; miRagen: Consultancy. Kim:Donga: Research Funding; Celltrion: Research Funding; J&J: Research Funding; Roche: Research Funding; Kyowa-Kirin: Research Funding; Novartis: Research Funding; Mundipharma: Research Funding. Jacobsen:Kura Oncology: Research Funding. Advani:Kyowa Kirin Pharmaceutical Developments, Inc.: Consultancy; Kura: Research Funding; Roche/Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Research Funding; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees; Autolus: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Research Funding; Agensys: Research Funding; Stanford University: Employment, Equity Ownership; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding; Celmed: Consultancy, Membership on an entity's Board of Directors or advisory committees; Forty-Seven: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Cell Medica, Ltd: Consultancy; Gilead Sciences, Inc./Kite Pharma, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Infinity Pharma: Research Funding; Millennium: Research Funding. Roncero:Kura Oncology: Research Funding. Terol:Janssen: Consultancy, Research Funding; Roche: Consultancy; Gilead: Research Funding; Astra Zeneca: Consultancy; Abbvie: Consultancy. Domingo-Domenech:Bristol-Myers Squibb: Other: Travel expenses; Roche: Other: Travel expenses; Seattle Genetics: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses. Piris:Millenium/Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Lecture Fees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jansen: Membership on an entity's Board of Directors or advisory committees, Other: Lecture Fees; Nanostring: Membership on an entity's Board of Directors or advisory committees; Kyowa Kirin: Membership on an entity's Board of Directors or advisory committees; Kura: Research Funding. Rodriguez:Kura Oncology: Research Funding. Bolognese:Kura Oncology: Consultancy. Kessler:Kura Oncology: Employment. Mishra:Kura Oncology: Employment. Curry:Kura Oncology: Employment. Kurman:Kura Oncology: Employment. Scholz:Kura Oncology: Employment, Equity Ownership, Patents & Royalties. Gualberto:Kura Oncology: Employment, Equity Ownership, Patents & Royalties.

Abstract Background Tipifarnib is a potent and selective inhibitor of the enzyme farnesyltransferase (FT). FT catalyzes post-translational attachment of farnesyl groups required for localization of signaling molecules to the inner cell membrane. CXCL12 is a chemokine that is essential for T cell homing to lymphoid organs and the bone marrow, and for the maintenance of immune cell progenitors. Herein we report preliminary efficacy, safety and biomarker data from a Phase 2 study of tipifarnib in angioimmunoblastic T-cell lymphoma (AITL) and CXCL12+ peripheral T-cell lymphoma (PTCL) patients (pts). Methods This Phase 2 study is a multi-institutional, single-arm, open-label trial initially designed as a two-stage (11+7 pts) cohort to determine the efficacy, safety and biomarkers of tipifarnib in pts with relapsed/refractory (R/R) PTCL, age >/=18 years and a performance status of 0-2. Based on initial findings, the study was amended to include a cohort of AITL (n=12) and PTCL (n=12) pts with the CXCL12 rs2839695 A/A genotype (CXCL12+ cohort). Pts received tipifarnib 300 mg administered orally twice daily on days 1-21 of 28-day treatment cycles until progression of disease (PD) or unacceptable toxicity. The primary endpoint of the study is overall response rate (ORR). Ancillary studies are also ongoing to investigate the prognostic value of CXCL12 expression in patients who received standard of care treatment. Results As of 25 July 2018, 34 PTCL pts (13 AITL, 1 ALK- ALCL, 20 PTCL-NOS) have been treated with tipifarnib, 19 pts in stages 1 and 2, and 15 pts in the ongoing AITL histology and CXCL12 cohorts. Median number of prior treatment regimens was 3. The most common treatment-related adverse events (AE) (grade ≥ 3) are hematological, including neutropenia (50%), thrombocytopenia (43%), leukopenia (33%), febrile neutropenia (27%), and anemia (20%). Skin and subcutaneous tissue disorders were reported in 9 pts, 6 of them with AITL histology. One pt with AITL experienced an episode of possible Stevens Johnson Syndrome that resolved with dose discontinuation and did not recur upon re-challenge at one dose level reduction. Of 18 evaluable patients enrolled in Stages 1 and 2 of the trial, 3 partial responses (PR), 2 of them in pts with AITL histology, and 4 best responses of stable disease (SD) were observed. Pre-treatment tumor tissue CXCL12 expression correlated with favorable pt outcomes. In the AITL cohort (10 evaluable pts), 1 PR and 1 SD have been observed so far, with 5 pts pending cycle 2 response evaluation. In the CXCL12+ cohort (n=3 evaluable pts), 1 SD has been observed, with 2 pts pending cycle 2 response evaluation. Plasma levels of CXCL12 decreased over time with tipifarnib treatment. Expression of CXCL12 mRNA and other biomarkers in pre-treatment biopsies of pts in the AITL and CXCL12+ cohorts are being evaluated using RT-PCR assays. In addition, the prognostic value of CXCL12 is being investigated in approximately 100 diagnostic specimens of PTCL pts who received standard therapy. Preliminary data suggest that CXCL12 overexpression is observed in approximately 25% of PTCL and negatively affects pt survival. Conclusion Preliminary activity of tipifarnib was observed in PTCL pts, particularly in those with tumors of AITL histology and high CXCL12 expression and enrollment continues. Disclosures Witzig: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Sokol:Mallinckrodt Pharmaceuticals: Consultancy; Seattle Genetics: Consultancy; Spectrum Pharmaceuticals: Consultancy. Jacobsen:Merck: Consultancy; Seattle Genetics: Consultancy. Kim:Takeda: Research Funding; J&J: Research Funding; Mundipharma: Research Funding; Roche: Research Funding; Novartis: Research Funding; Kyowa-Kirin: Research Funding; Celltrion: Research Funding. Foss:Miragen: Consultancy, Speakers Bureau; Spectrum: Consultancy; Seattle genetics: Consultancy; Mallinkrodt: Consultancy. Advani:Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Kura: Research Funding; Merck: Research Funding; Roche/Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding; Kyowa: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Regeneron: Research Funding; Janssen: Research Funding; Bayer: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Cell Medica: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Astra Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Autolus: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding; Gilead/Kite: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Millenium: Research Funding; Agensys: Research Funding; Celgene: Research Funding; Forty Seven: Research Funding; Infinity: Research Funding. Marin Niebla:Amgen: Other: Medical education of Staff, Speakers Bureau; Roche: Consultancy, Other: Medical education of Staff, Speakers Bureau; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Other: Medical education of Staff, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Medical education of Staff, Speakers Bureau. Piris:Kura: Honoraria; Takeda: Honoraria; Janssen: Honoraria; Gilead: Honoraria. Curry:Kura Oncology: Employment, Equity Ownership. Gualberto:Kura Oncology: Employment, Equity Ownership.

Abstract Background: CP-751,871, a fully human IgG2 subtype monoclonal antibody, is a potent and specific inhibitor of the insulin- like growth factor type I receptor (IGF-IR). The IGF-IR regulates the growth, survival, adhesion and invasiveness of multiple myeloma cells. High IGF-IR expression is observed in poor-prognostic subtypes of multiple myeloma and its inhibition has been long proposed as a potential therapeutic approach for treatment of this disease. Methods: A phase 1 dose escalation study was conducted to define the safety and tolerability, and to characterize the pharmacokinetic and pharmacodynamic (granulocyte surface IGF-IR expression and serum IGF-I levels) properties of CP-751,871 in patients with multiple myeloma. Patient’s eligibility included previously treated multiple myeloma in relapse or refractory phase including those less than complete remission to autologous stem cell transplant or tandem transplant. Results: Following informed consent and screening, 47 patients were enrolled into 11 dose-escalation cohorts of CP-751,871 at doses from 0.025 to 20 mg/Kg. Median patient age was 60 years. Median number of previous regimens was 4 (range 1–8). CP-751,871 was given as an IV infusion on Day 1 of 4-week cycles. Patients with a suboptimal response to CP-751,871 alone were eligible to receive CP-751,871 in combination with either oral dexamethasone and/or rapamycin at the discretion of the investigator. Twenty-seven patients received CP-751, 871 in combination with dexamethasone, while four patients received rapamycin in combination with either CP-751,871 or CP-751,871 and dexamethasone. Median number of treatment cycles was 3 (range 1–16). Ten patients were dosed at the highest cohort of 20 mg/Kg. No CP-751,871 related dose limiting toxicities were identified. Grade 3 toxicities were all observed at the 20 mg/Kg cohort (1 hyperglycemia, 1 anemia, 1 AST increase, 1 accidental fall, 1 muscle weakness). Plasma CP-751,871 exposure increased with dose, and the pharmacokinetic characteristics were consistent with target-mediated disposition. Granulocyte IGF-IR expression was maximally down-regulated for the entire duration of the dosing period at doses ≥1.5 mg/kg, indicating a saturation of circulating targets. CP-751,871 also led to a dose-dependent increase in circulating IGF-I concentrations. Tumor response was assessed according to Blade criteria. Two remissions and 4 partial remissions were reported in patients treated with different doses of CP-751,871 in combination with dexamethasone. Interestingly, the 2 patients with remission were previously found to be refractory to dexamethasone treatment. Conclusions: These data indicate that CP-751,871 is well tolerated either as a single agent or in combination with dexamethasone. Furthermore, CP-751,981 in combination with dexamethasone, may constitute a novel and effective therapeutic approach for patients with multiple myeloma.