Pharmacodynamic effects of MLN4924, a novel NAE inhibitor, on blood and skin

2562

Background: MLN4924 is a first-in-class, small molecule inhibitor of NEDD8 Activating Enzyme (NAE) with potent antitumor activity in animal models. Inhibition of NAE by MLN4924 leads to decreased neddylation and inhibition of cullin-RING ubiquitin ligase (CRL) activity. CRLs are enzyme complexes that control the ubiquitination and degradation of proteins with important roles in cell cycle and survival. Potent antitumor activity in animal models correlates with accumulation of substrates of the CRLs associated with DNA replication (e.g.Cdt-1), stress response (e.g.Nrf-2), and signal transduction (e.g. pIκB). Methods: A primary objective of this phase I trial in patients (pts) with advanced non-hematologic malignancies was to evaluate the pharmacodynamic (PD) effects of MLN4924 as measured by accumulation of pIκB in peripheral blood mononuclear cells (PBMCs) and Cdt-1 and Nrf-2 in skin. Pts were treated with a daily infusion of MLN4924 for 5 days of a 21-day cycle. PBMCs were isolated for analysis of pIκB levels at screening, baseline, and at selected time points following its administration. Skin biopsies for assay of Cdt-1 and Nrf-2 were performed at baseline and following the second dose of MLN4924. Results: 10 pts have been treated at 3 dose levels. Treatment emergent adverse events include elevations in transaminases, bilirubin and alkaline phosphatase. PK analysis indicated approximately dose-proportional increases in MLN4924 exposure with an estimated half life of 5 to 15 hours and no readily apparent drug accumulation. Analysis of pIκB levels in PBMCs demonstrated accumulation from baseline levels following administration of MLN4924. Cdt-1 and Nrf-2 levels in skin rose above baseline following the second dose of MLN4924. Conclusions: Treatment of pts with MLN4924 results in accumulation of substrates associated with inhibition of NAE in both peripheral blood and skin. Inhibition occurs at exposure levels that are comparable to those resulting in pharmacodynamic activity and in vivo tumor activity in xenograft models. Evidence of PD modulation of NAE activity through the accumulation of CRL substrates has been established in this early analysis, and dose escalation is ongoing to establish the MTD of this agent.

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Analysis of biomarkers during early phase clinical development of AMG 479, an investigational fully human monoclonal antibody antagonist of type 1 insulin-like growth factor receptor (IGF-1R)

3545

Background: AMG 479 showed anti-tumor activity in a phase 1 (P1) and phase 1b (P1b) trial (Tolcher, J Clin Oncol. 2007;25:3002; Sarantopoulos, J Clin Oncol. 2008;26:3583). We sought to identify predictive markers of response to AMG 479 in these trials by analyzing pharmacodynamic (PD) markers in serum, and expression and mutations of regulators of the IGF-1R pathway in tumors. Methods: Patients (pts) had advanced solid tumors and received AMG 479 (1–20 mg/kg Q2W) in the P1 trial or AMG 479 (6 or 12 mg/kg Q2W) + panitumumab (6 mg/kg Q2W) or gemcitabine (1,000 mg/m2 QW) in the P1b trial. Serum levels of IGF-1 and IGFBP-3 were measured pre dose on Day -1 and post dose at various time points. In the P1 trial, we examined relationships between tumor response (by RECIST) and: 1) levels of IGF-1 and IGFBP-3 (at baseline or PD change from baseline); 2) somatic mutations in key genes (including K-ras, and PTEN) of the IGF-1R pathway (in archival tumors); and 3) expression of PTEN (measured by immunohistochemistry in archival tumors). Results: Serum IGF-1 and IGFBP-3 increased in a concentration-dependent manner between 1 and 12 mg/kg AMG 479, with an apparent plateau between 12 and 20 mg/kg AMG 479. Baseline and PD changes in IGF-1 and IGFBP-3 were not substantially different in pts with a tumor response compared with those without a tumor response. A partial response to AMG 479 was observed in a pt with an activating K-ras mutation. No responses have been observed in tumors that lack expression of PTEN. Conclusions: The PD results suggest near complete biochemical coverage at 12-mg/kg AMG 479. Our hypothesis-generating analyses suggest that: 1) pre and postdose levels of IGF-1 and IGFBP-3 do not predict response to single-agent AMG 479; 2) activating K-ras mutations do not appear to preclude responsiveness to single-agent AMG 479 (in contrast to EGFR inhibitors); 3) expression and mutations of regulators of the PI3K/Akt pathway downstream of IGF-1R activation may be useful in predicting response to AMG 479.

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A phase II study of intravenous (IV) wild-type reovirus (Reolysin) in the treatment of patients with bone and soft tissue sarcomas metastatic to the lung

10524

Background: Reolysin is a Dearing strain, naturally occurring, ubiquitous human reovirus. The PKR (double stranded RNA-activated protein kinase) is inhibited and therefore the virus replicates specifically in transformed cells possessing an activated Ras pathway producing lysis. In vitro and in vivo studies with Reolysin in sarcoma cell lines revealed significant antitumor activity. Methods: This phase II open-label, single agent study was designed to characterize the efficacy and safety of Reolysin given IV every 28 days in patients (pts) with bone or soft tissue sarcoma with lung metastasis using a Simon two-stage design. 38 pts were accrued to the first stage. If 1 or more pts experience clinical benefit (prolonged SD > 6 months, partial or complete response) up to 52 pts could be accrued. The agent will be considered active if 3 or more responses or prolonged SD are observed. Results: Since July 2007, 43 pts age 19–76 (median 49) were enrolled (20 female) and received a total of 141 cycles (range 1–18). All pts had performance status 1 (29 pts) or 0 (14 pts). 38 pts received prior chemotherapy, radiotherapy, biological agents or combinations for their metastatic disease, 15 pts received more than 3 chemotherapy regimens. The sarcoma subtypes included: synovial sarcoma (13 pts), osteosarcoma (7 pts), leiomyosarcoma (7 pts), MFH (5 pts), Ewing/PNET (1 pt), chordoma (1 pt), others (9 pts). Side effects were mild to moderate (grade 1–2) and included constitutional symptoms fever, chills, fatigue. Two pts experienced respiratory side effects (cough and dyspnea) and 2 pts had diarrhea. Hematological side effects included grade 2–3 neutropenia (6 pts) and grade 2 thrombocytopenia (2 pts). One patient experienced grade 2 AST elevation. 33 pts are evaluable for response to date: 14 pts (42%) had SD for 2+ months including 5 pts having SD for more than 6 months. Conclusions: Utilization of single agent reovirus for treatment of sarcoma is a novel and unique therapeutic approach to date. Reolysin is well tolerated and shows promise for the treatment of metastatic sarcoma. Primary efficacy goals have been met. Accrual is ongoing to a total of 52 pts.

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A phase II study of the c-Met RTK inhibitor XL880 in patients (pts) with papillary renal-cell carcinoma (PRC)

15601

Background: XL880 is a novel inhibitor of receptor tyrosine kinases targeting MET and VEGFR2/KDR. (IC 50 for MET 0.4nM and KDR 0.8 nM). PRC is a rare (10–15%) subtype of kidney cancer which is notoriously resistant to systemic treatment. The familial form of PRC is associated with germline activating mutations of MET, while amplification and overexpression of MET is seen in the sporadic form. In an ongoing phase I dose escalation study of XL880 in forty patients with advanced solid tumors, five partial responses (PRs) were noted in 3 of 4 treated patients with PRC, and in two pts with thyroid cancer. The MTD in this study was 3.6 mg/kg of XL880 administered orally daily for 5 consecutive days every 2 weeks. Methods: In this phase 2 study, XL880 is administered orally as a single agent at a dose of 240 mg on days 1–5 of each 14 day cycle. Previously untreated pts with a histologic diagnosis of metastatic PRC are eligible and are stratified based on the presence or absence of MET germline mutations. Planned enrollment is 15 evaluable pts in each stratum. Inclusion criteria also include ECOG performance status < 3 and absence of brain metastases. Tumor response is assessed every 8 weeks by RECIST criteria. Archival primary tumor and lymph node metastasis were collected for pharmacodynamic assessments. Results: To date, 6 pts have been enrolled and received XL880. Five pts have tested negative for MET germline mutations; results for one pt are pending. Of 3 pts with at least one post baseline tumor assessment, 1 pt has demonstrated a PR and two pts have demonstrated stable disease > 3 months, one of whom has improvement in bone scan and bone pain. Hypertension has been reported in 2 pts who responded to anti- hypertensive treatment. Two SAEs have been reported as unrelated; pulmonary embolism and intratumoral hemorrhage. MET expression was detected in untreated primary and metastatic tumor. Reduction in Ki67, and an increase in TUNEL labeling were observed in the post treatment sample. Conclusions: XL880 is the 1st orally available small molecule inhibitor of MET to enter the clinic and appears to be generally well tolerated. Anti-tumor activity has been observed and XL880 may represent an active treatment option for pts with PRC. Enrollment continues and updated results will be presented.

No significant financial relationships to disclose.

A phase I study of a CanAg-targeted immunoconjugate, huC242-DM4, in patients with Can Ag-expressing solid tumors

3062

Background: HuC242-DM4 is a novel, targeted anti-cancer agent in development for the treatment of CanAg-expressing tumors such as carcinomas of the colon and pancreas. The compound is formed by the conjugation of the potent cytotoxic maytansinoid drug, DM4, to the humanized monoclonal antibody, huC242. This agent was highly active across a broad spectrum of CanAg-expressing human tumor xenograft models. Methods: Patients were enrolled with metastatic or inoperable colorectal, pancreatic, and other CanAg-expressing tumors who have failed standard therapy (about 95% of pts. had received = 4 prior chemotherapy regimens). Results: Thirty patients were treated with huC242-DM4, receiving a single intravenous (IV) infusion once every three weeks. Cohorts of 3 patients initially were enrolled on each dose level. Patients have received huC242-DM4 at 18, 36, 60, 90, 126, 168, 223, and 297 mg/m2. To date, dose limiting toxicity (DLT) was experienced by two of six patients treated at the 223 mg/m2 dose level during their second cycle of treatment. The patients experienced decreased visual acuity, corneal deposits and keratitis. Both patients were subsequently treated with lubricating eye drops. At present, these adverse events have markedly improved in one patient, while the other patient has completely returned to baseline. Of 10 patients treated at the168 mg/m2 dose level (including two patients who were dose reduced to 168 mg/m2), seven patients have received at least two cycles of treatment. One patient had grade 3 diarrhea and dehydration during his second cycle at 168 mg/m2. The latter improved with intravenous fluids. Preliminary pharmacokinetic data reveal a half-life of huC242-DM4 of about 5 days in patients with low plasma CanAg levels. In patients with high plasma CanAg levels (>900 units/mL), clearance of huC242-DM4 is increased. There has been no clinically significant myelosuppression and no formation of antibody to humanized antibody (HAHA) or drug (HADA). One patient had a 36% decline in CEA (not associated with tumor shrinkage). Conclusions: HuC242-DM4 was well tolerated at the 168 mg/m2 dose level. The MTD is not yet defined and approaches to prevent /ameliorate ocular toxicity are planned.

No significant financial relationships to disclose.

Phase I evaluation of a 24-h infusion of TAS-106 every 3 weeks (wks) in patients (pts) with solid tumors

2513

Background: The nucleoside 3’-C-ethynylcytidine (TAS-106) is metabolized in cancer cells to ethynylcytidine triphosphate (ECTP), an inhibitor of RNA polymerases I, II, and III. TAS-106 has potent anticancer activity in broad range of human tumor xenografts. In prior clinical studies, bolus intravenous (IV) TAS-106 caused reversible dose-limiting peripheral neuropathy and the recommended phase II dose (RP2D) was 4.21 mg/m2 every 3 wks. Myelosuppression, asthenia, and mild nausea and vomiting were also common. In rats, 24-h TAS-106 infusions are better tolerated with equivalent efficacy. Therefore, a Phase I study of 24-h infusions of TAS-106 was initiated. Methods: Escalating doses TAS-106 infused over 24-h every 3 wks were administered to cancer patients with pharmacokinetic (PK) monitoring during the initial cycle. Toxicity and response were assessed using NCI CTC (v2) grade (gr) and RECIST, respectively. Plasma and urine TAS-106 concentrations were monitored using LC/MS/MS methods. Results: Overall, 33 pts were treated at the following dose levels: 2.82 (4 pts), 3.5 (5 pts), 4.38 (6 pts), 5.48 (4 pts) 6.85 (6 pts) and 8.56 mg/m2 (8 pts). At 8.56 mg/m2, 2 of 5 pts experienced neutropenic DLTs (febrile neutropenia and gr 4 neutropenia lasting greater than or equal to 3 days) No neuropathy DLTs were observed. At 6.85 mg/m2, gr 3 peripheral neuropathy in cycle 1 was observed in 1 patient, but no other DLTs occurred in 5 patients. Other common drug related toxicities occurring in any cycle included gr 1–2 fatigue (13 pts), gr 3–4 neutropenia (10 pts), gr 1 hand/foot syndrome (9 pts), gr 2–3 anemia (9 pts) gr 1 rash/skin exfoliation (10 pts), and peripheral neuropathy gr 1–2 (5 pts). No objective responses were seen; although 3 pts with parotid, adenoid cystic, and breast cancers demonstrated stable disease for 5, 6, and 7 months, respectively. Plasma concentrations increased with increasing dose, and at 6.85 mg/m2, the Cmax was 77.4±7.3 ng/mL, AUC 1,892±54 ng·h/mL, CL 102±13 mL/h/kg, VDss 1.37±.05 L/kg, and t1/2 was 9.85±1.47 h. Over 48 h, 62.1% of the administered dose of TAS-106 was excreted into the urine. Conclusions: Compared with bolus dosing, 24-h infusions of TAS-106 are better tolerated with less peripheral neuropathy. The RP2D for TAS-106 infused over 24-h every 3 wks is 6.85 mg/m2.

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A phase I, pharmacokinetic (PK) and pharmacodynamic (PD) study of the combination of an oral antimicrotubular agent, DJ-927 (D), and capecitabine (C) in patients (Pts) with advanced cancers

2016

Background: DJ-927, an oral microtubule stabilizer, has impressive cytotoxic activity in taxane-resistant tumors and an acceptable toxicity profile. C and Taxane combinations are active in solid tumors such as breast cancer. Non-overlapping mechanism of action and toxicity profiles and the convenience of an orally administered therapy have prompted a phase I evaluation of the combination. D was given orally once on day 1 and C for 14-days (D1–14), every three weeks. Methods: Eligible pts had evaluable cancer, minimal prior therapy and PS 0 - 2 ECOG. D was started at 18 mg/m2 on day 1 along with 1,250 mg/m2 of C orally B.I.D for 14 days, of a 21-day cycle. Incremental doses of both drugs were explored until the maximum tolerated dose (MTD) was reached. PK samples were collected during cycles 1 and 2, for assays of C and for D when given concurrently with C during cycle 1 and D given alone during cycle 2. Results: Twenty-seven pts [18 Male/ 9 Female; median age (range)- 58 yrs (33–70); PS 0 (n=8) ; PS 1 (n=19)] received 81 cycles [median (range)- 3 (1–8)] in 5 cohorts, with D and C 18/ 1250 mg/m2 (n = 3), 27/ 1250 mg/m2 (n = 7), 27/ 1900 mg/m2 (n = 7), 35/ 1900 mg/m2 (n = 3),and 27/ 2500 mg/m2 (n = 7). Dose-limiting toxicity (DLT) was grade 4 neutropenia in 2 of 3 pts at 35/ 1900 mg/m2 dose. Other common drug-related toxicities were leukopenia, nausea & vomiting (12 pts each, 44.4%), neutropenia, diarrhea and hand-foot syndrome (11 pts each, 40.7%), and fatigue (7 pts, 25.9%). A pt with hepatocellular carcinoma had an unconfirmed partial response at cycle 2 and 10 pts experienced disease stabilization lasting ≥ 12 weeks. The median elimination half-life (t½) of D was 182 hrs for cycle 1 (with C) and 204 hrs for cycle 2 (without C). Median tmax values for D with and without C occurred at 2 hours. Median clearance values (CL/F) for D in plasma were similar with and without C at 18.4 L/h/m2 and 19.8 L/h/m2, respectively. Conclusions: The combination of D and C is feasible and safe at the MTD of 27 mg/m2 and 2500 mg/m2, respectively. Co-administering C with D did not alter the PK of either drug. Preliminary evidence of antitumor activity suggests that further studies of this combination are warranted.

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MDX-070, a human anti-plasma antibody, administered as either a single dose or as multiple doses to patients with hormone-refractory prostate cancer

14549

Background: Prostate-specific membrane antigen (PSMA) is a type II transmembrane glycoprotein that is specifically expressed in prostatic epithelial cells and up-regulated in hormone refractory prostate cancer (HRPC). MDX-070 is a HuMAb that recognizes conformational epitopes on PSMA, mediates anti-body-dependent cellular cytotoxicity (ADCC), and is internalized. The primary objective of these studies was to establish the safety and tolerability and maximum tolerated dose (MTD) of MDX070 in patients (pts) with HRPC. Secondary objectives included characterization of the pharmacokinetic (PK) profile and a preliminary assessment of clinical antitumor activity measured by PSA levels and scans. Methods: MDX070 was administered intravenously over 90 minutes to pts with HRPC as either a single dose (Protocol MDX070–01) at dose levels of 0.1 (3 pts), 0.5 (3 pts), 1 (3 pts), 5 (3 pts), or 10 (6 pts) mg/kg/dose or every two weeks for up to 4 doses (Protocol MDX070–02) at dose levels of 1 (9 pts), 5 (6 pts), and 10 (15 pts) mg/kg/dose. Pts with stable disease or better at the end of the treatment period could receive additional treatment cycles until progression in a companion protocol (MDX070–03). Results: There were no Grade 4 toxicities judged to be related to MDX070 administration. One patient experienced Grade 3 anorexia that was possibly drug-related (5 mg/kg). Grade 1 or 2 toxicities (reported in 35 pts in the clinical database- 18 in 01, and 17 in 02) deemed to be related to MDX070 included anorexia (2), fatigue (3), fever (4), nausea (3) and vomiting (2). No significant differences in toxicity were seen between dose groups. No >50% decline in PSA or response according to RECIST criteria occurred in any of the dosing cohorts, but 6 patients had stable disease and received 1 or more additional cycles of treatment at the same dose. Conclusions: MDX-070 as monotherapy, at the dose levels administered, was safe and well tolerated. No objective antitumor activity was observed at the dose levels tested, however, 20% (6/30) had stable disease. Enrollment is continuing at the 10 mg/kg multi-dose cohort. PK analysis is ongoing.

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