Phase I assessment of new mechanism-based pharmacodynamic biomarkers for MLN8054, a small-molecule inhibitor of Aurora A kinase

The mitotic kinase Aurora A is an important therapeutic target for cancer therapy. This study evaluated new mechanism-based pharmacodynamic biomarkers in cancer patients in two phase I studies of MLN8054, a small-molecule inhibitor of Aurora A kinase. Patients with advanced solid tumors received MLN8054 orally for 7 consecutive days in escalating dose cohorts, with skin and tumor biopsies obtained before and after dosing. Skin biopsies were evaluated for increased mitotic cells within the basal epithelium. Tumor biopsies were assessed for accumulation of mitotic cells within proliferative tumor regions. Several patients in the highest dose cohorts showed marked increases in the skin mitotic index after dosing. Although some tumors exhibited increases in mitotic cells after dosing, others displayed decreases, a variable outcome consistent with dual mechanisms of mitotic arrest and mitotic slippage induced by antimitotics in tumors. To provide a clearer picture, mitotic cell chromosome alignment and spindle bipolarity, new biomarkers of Aurora A inhibition that act independently of mitotic arrest or slippage, were assessed in the tumor biopsies. Several patients, primarily in the highest dose cohorts, had marked decreases in the percentage of mitotic cells with aligned chromosomes and bipolar spindles after dosing. Evidence existed for an exposure-effect relationship for mitotic cells with defects in chromosome alignment and spindle bipolarity that indicated a biologically active dose range. Outcomes of pharmacodynamic assays from skin and tumor biopsies were concordant in several patients. Together, these new pharmacodynamic assays provide evidence for Aurora A inhibition by MLN8054 in patient skin and tumor tissues.

Phase 1 study of MLN8054, a selective inhibitor of Aurora A kinase in patients with advanced solid tumors

PURPOSE

Aurora A kinase is critical in assembly and function of the mitotic spindle. It is overexpressed in various tumor types and implicated in oncogenesis and tumor progression. This trial evaluated the dose-limiting toxicities (DLTs) and maximum tolerated dose (MTD) of MLN8054, a selective small-molecule inhibitor of Aurora A kinase.

METHODS

In this first-in-human, dose-escalation study, MLN8054 was given orally for 7, 14, or 21 days followed by a 14-day treatment-free period. Escalating cohorts of 3-6 patients with advanced solid tumors were treated until DLT was seen in ≥2 patients in a cohort. Serial blood samples were collected for pharmacokinetics and skin biopsies were collected for pharmacodynamics.

RESULTS

Sixty-one patients received 5, 10, 20, 30, or 40 mg once daily for 7 days; 25, 35, 45, or 55 mg/day in four divided doses (QID) for 7 days; or 55, 60, 70, or 80 mg/day plus methylphenidate or modafinil with daytime doses (QID/M) for 7-21 days. DLTs of reversible grade 3 benzodiazepine-like effects defined the estimated MTD of 60 mg QID/M for 14 days. MLN8054 was absorbed rapidly, exposure was dose proportional, and terminal half-life was 30-40 h. Three patients had stable disease for >6 cycles.

CONCLUSIONS

MLN8054 dosing for up to 14 days of a 28-day cycle was feasible. Reversible somnolence was dose limiting and prevented achievement of plasma concentrations predicted necessary for target modulation. A recommended dose for investigation in phase 2 trials was not established. A second-generation Aurora A kinase inhibitor is in development.

Phase 1 pharmacokinetic and drug-interaction study of dasatinib in patients with advanced solid tumors

BACKGROUND

The recently developed the Src and Abelson (Abl) kinase inhibitor dasatinib has antitumor effects in epithelial and mesenchymal tumors. Preclinical data have indicated that dasatinib is metabolized primarily through cytochrome P450 3A4 (CYP3A4) and may cause QT prolongation. In light of its improved tolerability, the authors were interested in the safety of a once-daily dasatinib regimen.

METHODS

The authors conducted a phase 1 trial of dasatinib in 29 patients with advanced solid tumors. Segment 1 of the trial was short term and sequential and was designed to determine whether the coadministration of the potent CYP3A4 inhibitor ketoconazole had an effect on the pharmacokinetics of dasatinib. Segment 2 was designed to evaluate the safety of dasatinib as dosing was increased. QT intervals were monitored closely in both segments. Efficacy was assessed in Segment 2 using both positron emission tomography and computed tomography.

RESULTS

Hematologic toxicities were markedly less than those observed in patients with leukemia, whereas nonhematologic toxicities were similar. The authors determined that the maximum recommended dose was 180 mg once daily based on the incidence of pleural effusion. Coadministration of ketoconazole led to a marked increase in dasatinib exposure, which was correlated with an increase in corrected QT (QTc) values of approximately 6 msec. No adverse cardiac events were observed.

CONCLUSIONS

The dose-limiting toxic effect for dasatinib was pleural effusion. The pharmacokinetic and cardiac studies indicated that coadministration of dasatinib with potent CYP3A4 inhibitors or agents that prolong the QTc interval should be avoided if possible. Close monitoring for toxicity and dose reduction should be considered if the coadministration of such agents cannot be avoided.

Pharmacokinetic and pharmacodynamic study of two doses of bortezomib in patients with relapsed multiple myeloma

PURPOSE

Characterize bortezomib pharmacokinetics/pharmacodynamics in relapsed myeloma patients after single and repeat intravenous administration at two doses.

METHODS

Forty-two patients were randomized to receive bortezomib 1.0 or 1.3 mg/m(2), days 1, 4, 8, 11, for up to eight 21-day treatment cycles (n = 21, each dose group). Serial blood samples for pharmacokinetic/pharmacodynamic analysis were taken on days 1 and 11, cycles 1 and 3. Observational efficacy and safety data were collected.

RESULTS

Twelve patients in each dose group were evaluable for pharmacokinetics/pharmacodynamics. Plasma clearance decreased with repeat dosing (102-112 L/h for first dose; 15-32 L/h following repeat dosing), with associated increases in systemic exposure and terminal half-life. Systemic exposures of bortezomib were similar between dose groups considering the relatively narrow dose range and the observed pharmacokinetic variability, although there was no readily apparent deviation from dose-proportionality. Blood 20S proteasome inhibition profiles were similar between groups with mean maximum inhibition ranging from 70 to 84% and decreasing toward baseline over the dosing interval. Response rate (all 42 patients) was 50%, including 7% complete responses. The safety profile was consistent with the predictable and manageable profile previously established; data suggested milder toxicity in the 1.0 mg/m(2) group.

CONCLUSIONS

Bortezomib pharmacokinetics change with repeat dose administration, characterized by a reduction in plasma clearance and associated increase in systemic exposure. Bortezomib is pharmacodynamically active and tolerable at 1.0 and 1.3 mg/m(2) doses, with recovery toward baseline blood proteasome activity over the dosing interval following repeat dose administration, supporting the current clinical dosing regimen.

Abstract A6: Pazopanib combination with paclitaxel and carboplatin in patients with advanced solid tumors and gynecological cancers: Results of two phase I studies

Background: Pazopanib (PAZ) is an oral angiogenesis inhibitor targeting VEGFR, PDGFR, and c-Kit with w/ a recommended dose of 800 mg/day as monotherapy. Preclinical activity supports combining PAZ with paclitaxel (P) and carboplatin (C). Safety, PK, and and clinical activity of PAZ with P and and C were evaluated in two Phase I studies.

Methods: Two Phase I studies were conducted using a once daily QD regimen of PAZ (200–800 mg), and once every Q21 days of C (AUC 4–6 mg·min/mL) and P (175 mg/m2) to determine the optimally tolerated regimen (OTR) MTD defined as a dose limiting toxicity (DLT) frequency of <33% in Cycle 1. Study 1 (S1) was a 3 + 3 design expanded at the OTR in patients (pts) with w/ metastatic disease treated with w/ no more than 3 prior lines of therapy. Study 2 (S2) enrolled subjects with w/ gynecological cancer in 2 cohorts of 6 pts each as first-1st line treatment.

Results: In Study 1S1, 34 pts (mean age 54; M/F: 17/17; ECOG 0/1: 19/15) were enrolled. Breast (29%) and esophagus (12%) were the most common primary tumor sites. In Study 2S2, 12 pts (mean age 53.754, M/F: 0/12; ECOG 0/1: 8/4) were enrolled. Ovary (50%) and endometrium/uterus (25%) were the most common primary tumor sites. The frequency of adverse events (AEs), regardless of causality, in the 2 studies (1 vs 2), were similar for neutropenia (82% vs 75%) and fatigue (68% vs 75%) and different for nausea (71% vs 50%), thrombocytopenia (68% vs 33%), anemia (65% vs 25%), and abdominal pain (24% vs 50%). The OTR MTD in Study 1S1 was P 175, C AUC 5, and PAZ 200; an OTR MTD was not determined for Study 2S2 due to poor tolerability. In Study 1S1, in the presence of PAZ 200 mg and 400, mg, the AUC (0–23) of C increased by 41 and 31%, respectively and while the Cmax for P increased by 43 and 40%, respectively. Best response in Study 1S1 at the OTRMTD (n=13) was CR [2 pts (15%); 406 and 446 days] and PR [3 pts (23%); 42–208 days].

Conclusions: Full doses of PAZ and C were not tolerated in combination with w/ P due predominantly to hematologicale toxicities in Study 1S1 and to non-hemeatological toxicities in Study 2S2. A drug interaction between PAZ and P and C along with more extensive prior therapy may explain increased myelotoxicity with this triplet in Study 1S1. Based on this PK interaction, lower doses of P and C may still provide adequate therapeutic exposure and better safety profile when combined with a higher dose of PAZ relative to the OTR MTD in study.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A6.

Phase 1-2a multicenter dose-escalation study of ezatiostat hydrochloride liposomes for injection (Telintra, TLK199), a novel glutathione analog prodrug in patients with myelodysplastic syndrome

BACKGROUND

Ezatiostat hydrochloride liposomes for injection, a glutathione S-transferase P1-1 inhibitor, was evaluated in myelodysplastic syndrome (MDS). The objectives were to determine the safety, pharmacokinetics, and hematologic improvement (HI) rate. Phase 1-2a testing of ezatiostat for the treatment of MDS was conducted in a multidose-escalation, multicenter study. Phase 1 patients received ezatiostat at 5 dose levels (50, 100, 200, 400 and 600 mg/m2) intravenously (IV) on days 1 to 5 of a 14-day cycle until MDS progression or unacceptable toxicity. In phase 2, ezatiostat was administered on 2 dose schedules: 600 mg/m2 IV on days 1 to 5 or days 1 to 3 of a 21-day treatment cycle.

RESULTS

54 patients with histologically confirmed MDS were enrolled. The most common adverse events were grade 1 or 2, respectively, chills (11%, 9%), back pain (15%, 2%), flushing (19%, 0%), nausea (15%, 0%), bone pain (6%, 6%), fatigue (0%, 13%), extremity pain (7%, 4%), dyspnea (9%, 4%), and diarrhea (7%, 4%) related to acute infusional hypersensitivity reactions. The concentration of the primary active metabolites increased proportionate to ezatiostat dosage. Trilineage responses were observed in 4 of 16 patients (25%) with trilineage cytopenia. Hematologic Improvement-Erythroid (HI-E) was observed in 9 of 38 patients (24%), HI-Neutrophil in 11 of 26 patients (42%) and HI-Platelet in 12 of 24 patients (50%). These responses were accompanied by improvement in clinical symptoms and reductions in transfusion requirements. Improvement in bone marrow maturation and cellularity was also observed.

CONCLUSION

Phase 2 studies of ezatiostat hydrochloride liposomes for injection in MDS are supported by the tolerability and HI responses observed. An oral formulation of ezatiostat hydrochloride tablets is also in phase 2 clinical development.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT00035867.

An open-label clinical trial evaluating safety and pharmacokinetics of two dosing schedules of panitumumab in patients with solid tumors

PURPOSE

This study evaluated safety, pharmacokinetics, and efficacy of 2 dose schedules and 2 infusion times of panitumumab in patients with advanced solid malignancies.

PATIENTS AND METHODS

This phase I multicenter, open-label study sequentially enrolled patients with advanced solid tumors refractory to standard therapy, or for which no standard therapy exists, to receive panitumumab 6 mg/kg every 2 weeks or 9 mg/kg every 3 weeks. Patients receiving panitumumab every 2 weeks received either all infusions over 60 minutes or a 60-minute infusion for the first dose followed by 30-minute infusions if the first infusion was well tolerated. Patients in the every-3-week cohort received 60-minute infusions. Safety outcomes included the incidence of adverse events and antipanitumumab antibody formation. Pharmacokinetic properties were determined. Efficacy endpoints included response rate and duration of response.

RESULTS

Eighty-six patients were enrolled; 84 (98%) received panitumumab. Treatment-related adverse events occurred in 90% of patients. Safety profiles were similar between patients receiving 30-minute (n = 20) and 60-minute (n = 43) infusions every 2 weeks and patients receiving panitumumab every 3 weeks (n = 21). Panitumumab exposure at steady state increased dose proportionally, and peak serum concentrations were similar in patients receiving either 30- or 60-minute infusions every 2 weeks. Objective responses were seen in 4 patients (5%) with colon, rectal, esophageal, and bladder cancers.

CONCLUSION

Similar drug exposures and safety profiles were observed in patients receiving panitumumab 6 mg/kg every 2 weeks with either 30- or 60-minute infusions and antitumor activity was seen in some patients. Exposure increased approximately dose proportionally at steady state.

Histone deacetylase inhibitor panobinostat induces clinical responses with associated alterations in gene expression profiles in cutaneous T-cell lymphoma

PURPOSE

Histone deacetylase inhibitors can alter gene expression and mediate diverse antitumor activities. Herein, we report the safety and activity of the histone deacetylase inhibitor panobinostat (LBH589) in cutaneous T-cell lymphoma (CTCL) and identify genes commonly regulated by panobinostat.

EXPERIMENTAL DESIGN

Panobinostat was administered orally to patients with CTCL on Monday, Wednesday, and Friday of each week on a 28-day cycle. A dose of 30 mg was considered excessively toxic, and subsequent patients were treated at the expanded maximum tolerated dose of 20 mg. Biopsies from six patients taken 0, 4, 8, and 24 h after administration were subjected to microarray gene expression profiling and real-time quantitative PCR of selected genes.

RESULTS

Patients attained a complete response (n = 2), attained a partial response (n = 4), achieved stable disease with ongoing improvement (n = 1), and progressed on treatment (n = 2). Microarray data showed distinct gene expression response profiles over time following panobinostat treatment, with the majority of genes being repressed. Twenty-three genes were commonly regulated by panobinostat in all patients tested.

CONCLUSIONS

Panobinostat is well tolerated and induces clinical responses in CTCL patients. Microarray analyses of tumor samples indicate that panobinostat induces rapid changes in gene expression, and surprisingly more genes are repressed than are activated. A unique set of genes that can mediate biological responses such as apoptosis, immune regulation, and angiogenesis were commonly regulated in response to panobinostat. These genes are potential molecular biomarkers for panobinostat activity and are strong candidates for the future assessment of their functional role(s) in mediating the antitumor responses of panobinostat.

New therapeutic directions for advanced pancreatic cancer: targeting the epidermal growth factor and vascular endothelial growth factor pathways

In advanced pancreatic cancer, single-agent gemcitabine became the standard therapy approximately 10 years ago. Subsequently, combinations of gemcitabine with fluorouracil, cisplatin, irinotecan, oxaliplatin, or pemetrexed produced no clear survival benefit. Among the newer approaches, targeting human epidermal growth factor receptor (HER-1/EGFR) shows promise. The U.S. Food and Drug Administration recently approved erlotinib (a HER-1/EGFR tyrosine kinase inhibitor) combined with gemcitabine for the first-line treatment of advanced pancreatic cancer. This combination showed a statistically significant survival benefit over gemcitabine alone in locally advanced or metastatic disease (the median overall survival time was 6.24 months versus 5.91 months; hazard ratio, 0.82; p = .038); however, the clinical significance of this survival difference has been questioned. Additionally, a large phase III trial where the addition of cetuximab (an anti-HER-1/EGFR monoclonal antibody [mAb]) to gemcitabine failed to result in a longer overall survival time than with gemcitabine alone has been reported. Targeting vascular endothelial growth factor (VEGF) with bevacizumab (a recombinant, humanized IgG1 mAb that binds to VEGF) in combination with gemcitabine was investigated in a phase II trial, with promising outcomes that were unfortunately not supported by a subsequent phase III study. While the future treatment of pancreatic cancer may be influenced by the potential of certain biomarkers to predict better response to molecular-targeted therapies, allowing individualization of patient therapy, there are currently no clear candidates, and this remains an interesting area for further investigation.

Enzastaurin, an oral serine/threonine kinase inhibitor, as second- or third-line therapy of non-small-cell lung cancer

PURPOSE

Enzastaurin, an oral serine/threonine kinase inhibitor, suppresses protein kinase C (PKC) and protein kinase B/AK transforming (AKT) signaling, induces tumor cell apoptosis, and inhibits proliferation and angiogenesis. Increased PKC and AKT activity is associated with poor prognosis in non-small-cell lung cancer (NSCLC). This phase II trial of enzastaurin was conducted to determine the 6-month progression-free survival (PFS) rate in advanced, metastatic NSCLC.

PATIENTS AND METHODS

Patients with metastatic (stage IV and wet IIIB) NSCLC, Eastern Cooperative Oncology Group performance status <or= 2, and <or= two prior systemic regimens (including one or more platinum-based chemotherapy regimens) received 500 mg of enzastaurin administered once daily.

RESULTS

Fifty-five patients were enrolled (55% male patients, 45% female patients; median age, 63 years; range, 44 to 82 years; 78% of patients having stage IV disease). Adenocarcinoma was the most common diagnosis (65%). Prior therapies included radiotherapy (73%) and epidermal growth factor inhibitors (29%). Median PFS was 1.8 months (95% CI, 1.7 to 1.9). Six-month PFS rate was 13% (95% CI, 3.9% to 21.5%). Median overall survival (OS) was 8.4 months (95% CI, 6.0 to 13.6 months). The 12-month OS rate was 44% (95% CI, 30.5% to 57.3%). Nineteen patients (35%) had stable disease. No objective responses were observed. Seven patients (13%) had PFS >or= 6 months, three of whom continued for more than 10 months. The most common toxicity was fatigue (grade <or= 3; n = 17). Grade 3 or worse toxicities were fatigue (n = 2), thromboembolism (n = 1), ataxia (n = 1), and anemia (n = 1). Two patients discontinued treatment because of drug-related fatigue and dizziness. Five patients died while enrolled in the study (non drug-related).

CONCLUSION

Although the primary end point of a 20% PFS rate was not achieved, 13% of the patients had PFS for >or= 6 months. Given the tolerability and survival data, evaluation of enzastaurin in combination with cytotoxic drugs is warranted in NSCLC.

Dose- and schedule-dependent inhibition of the mammalian target of rapamycin pathway with everolimus: a phase I tumor pharmacodynamic study in patients with advanced solid tumors

PURPOSE

Everolimus is a selective mammalian target of rapamycin (mTOR) inhibitor with promising anticancer activity. In order to identify a rationally based dose and schedule for cancer treatment, we have conducted a tumor pharmacodynamic phase I study in patients with advanced solid tumors.

PATIENTS AND METHODS

Fifty-five patients were treated with everolimus in cohorts of 20, 50, and 70 mg weekly or 5 and 10 mg daily. Dose escalation depended on dose limiting toxicity (DLT) rate during the first 4-week period. Pre- and on-treatment steady-state tumor and skin biopsies were evaluated for total and phosphorylated (p) protein S6 kinase 1, eukaryotic initiation factor 4E (elF-4E) binding protein 1 (4E-BP1), eukaryotic initiation factor 4G (eIF-4G), AKT, and Ki-67 expression. Plasma trough levels of everolimus were determined on a weekly basis before dosing during the first 4 weeks.

RESULTS

We observed a dose- and schedule-dependent inhibition of the mTOR pathway with a near complete inhibition of pS6 and peIF-4G at 10 mg/d and >or= 50 mg/wk. In addition, pAKT was upregulated in 50% of the treated tumors. In the daily schedule, there was a correlation between everolimus plasma trough concentrations and inhibition of peIF4G and p4E-BP1. There was good concordance of mTOR pathway inhibition between skin and tumor. Clinical benefit was observed in four patients including one patient with advanced colorectal cancer achieving a partial response. DLTs occurred in five patients: one patient at 10 mg/d (grade 3 stomatitis) and four patients at 70 mg/wk (two with grade 3 stomatitis, one with grade 3 neutropenia, and one with grade 3 hyperglycemia).

CONCLUSION

Everolimus achieved mTOR signaling inhibition at doses below the DLT. A dosage of 10 mg/d or 50 mg/wk is recommended for further development.

A phase I study (CA180021-Segment 2) of dasatinib in patients (pts) with advanced solid tumors

14042

Background: SPRYCEL™ is a potent, orally active, multi-targeted kinase inhibitor, active against BCR-ABL and SRC family kinases. We report the results of a Phase I dose-escalation study evaluating safety, tolerability, pharmacokinetics, and biomarkers of dasatinib in pts with advanced solid tumors. Methods: Pts with adequate hematologic, renal, cardiac and liver function received oral dasatinib once daily for 7 days per week. Three doses and schedules were examined: 90 mg BID; 140 mg QD; and 180 mg QD. Pharmacokinetics and pharmacodynamic biomarkers were collected on Days 1 and 26 of Cycle 1. Tissue biomarkers were assessed at screening. CT was performed at least every 8 weeks, and FDG-PET at weeks 4, and 8. Results: 26 pts [M=15, F=11] ECOG PS ≤ 2 with epithelial tumors (n=14) or other solid tumors (n=12) have been treated in escalating dose levels. Toxicity was generally mild; most patients came off study for progressive disease. DLTs of pleural effusions were seen in 3/9 subjects on the 180 mg cohort, 2 of whom had pre-existing effusions. Patients with pleural effusion have been excluded from future enrollment. The maximum tolerated dose has not been identified. There have been no objective responses on CT. Six patients have had stable disease with continued study treatment for 2–10 months. Conclusions: Dasatinib can be safely administered at doses of 140 and 180 mg QD. Clinical efficacy, pharmacokinetics, and correlative studies of tumor biopsy material and early FDG-PET results will be reported.

No significant financial relationships to disclose.

A phase IB safety and pharmacokinetic (PK) study of recombinant human Apo2L/TRAIL in combination with rituximab in patients with low-grade non-Hodgkin lymphoma

8078

Background: Recombinant human Apo2L/TRAIL (rhApo2L/TRAIL) induces apoptosis (programmed cell death) through binding to the pro-apoptotic receptors DR4 and DR5. Preclinical studies show that rhApo2L/TRAIL selectively induces apoptosis in many cancer cell lines derived from various malignancies including NHL, while sparing most normal cells. In vivo, rhApo2L/TRAIL and Rituximab cooperate to shrink or attenuate the growth of various NHL tumor xenografts in SCID mice. RhApo2L/TRAIL is being co-developed by Genentech and Amgen as a targeted therapy for solid tumors and hematologic malignancies. Methods: Subjects were eligible to participate if they had CD20+ follicular NHL or small lymphocytic lymphoma or marginal zone B-cell lymphoma that had progressed following stable disease or an objective response lasting > 6 months duration to the most recent rituximab-contain regimen. RhApo2L/TRAIL is administered intravenously over 1 hour for 5 consecutive days every three weeks up to 4 cycles at dose levels of 4 and 8 mg/kg. Rituximab is administered intravenously at 375 mg/m2 weekly for up to eight doses. Results: Six subjects with low grade NHL (4 with follicular NHL and 2 with small cell NHL) have been enrolled and treated with 4 mg/kg rhApo2L/TRAIL and rituximab, and one subject (with follicular NHL) has been enrolled and treated with 8 mg/kg rhApo2L/TRAIL and rituximab. The enrolled subjects range in age from 39–82 years; there are 6 male and 1 females. The number of prior therapies for NHL range from 1–8. Four subjects have received all protocol specified therapy. There have been no DLTs or SAEs or Grade 3/4 adverse events reported to date. To date, five subjects have undergone tumor response assessment: there have been 2 patients with complete response, 1 with partial response and 2 with stable disease. Conclusion: The combination of rhApo2L/TRAIL at 4 mg/kg/day and rituximab appears safe and shows evidence of activity in subjects with low grade NHL that has relapsed following previous rituximab-containing therapy. Enrollment is continuing to test rhApo2L/TRAIL at 8 mg/kg plus rituximab for expanded safety data and further dose optimization.

No significant financial relationships to disclose.

Safety and pharmacokinetics (PK) of AMG 706 with panitumumab plus FOLFIRI or FOLFOX for the treatment of patients (pts) with metastatic colorectal cancer (mCRC)

4081

Background: AMG 706 is an oral, investigational multikinase (MKI) inhibitor with antiangiogenic and direct antitumor activity, selectively targeting VEGF, PDGF and Kit receptors. Methods: This is an ongoing phase 1b, open-label, dose-finding study of AMG 706 with panitumumab plus FOLFIRI or FOLFOX in pts with mCRC. Objectives are to establish safety, PK, and the maximum tolerated dose of AMG 706 with this regimen. Pts =18 yrs with mCRC, ECOG 0–1, =1 prior chemotherapy for advanced disease and no prior oral VEGFr MKIs or anti-EGFR therapy, received either FOLFIRI or FOLFOX (based on prior therapy) plus panitumumab (6mg/kg IV day 1 of each 2-wk cycle), and escalating doses of AMG 706 (50, 75, 125mg QD; 75mg BID) given continuously from day 3 of cycle 1. Assessments included dose-limiting toxicities (DLT) during the first 2 cycles and tumor response (every 6–8 wks from wk 6). Results: As of Nov 2006, 45 pts were enrolled and received at least 1 dose of AMG 706 (FOLFIRI/FOLFOX n=33/12); 64% had prior chemotherapy. There were 6 DLTs: FOLFIRI n=4, all grade 3 (diarrhea n=2: 50mg QD, 75mg BID; deep vein thrombosis n=1: 75mg QD; high GI output n=1: 75mg BID); FOLFOX n=2 (all fatigue, grade 3: 50mg QD). Treatment-related adverse events (AE) occurring in =10% of pts included: any AE, FOLFIRI/FOLFOX 88/92% of pts (grade 3, 21/58%); fatigue 55/58% (12/33%), anorexia 24/50% (0/0%), diarrhea 24/33% (0/8%), epistaxis 27/0% (0/0%) and hypertension 15/8% (0/0%). There were no grade 4/5 AEs. 2 cases of cholecystitis (grade 3, n=1) occurred. Preliminary data showed that AMG 706 PK at 50mg QD (FOLFOX) and 50–125mg QD (FOLFIRI) was comparable to data from monotherapy studies at the same dose levels. AMG 706 did not markedly alter the PK profiles of irinotecan or its metabolites. Objective tumor response per RECIST is shown in the table . Conclusions: In this study of pts with mCRC, AMG 706 was tolerable when combined with panitumumab and FOLFIRI or FOLFOX, with little effect on AMG 706 PK.

[Table: see text]

No significant financial relationships to disclose.

A phase II study of enzastaurin as second- or third-line treatment of non-small cell lung cancer (NSCLC)

7543

Background: Enzastaurin, an oral serine/threonine kinase inhibitor, suppresses signaling through PKC and the PI3K/AKT pathway, induces tumor cell apoptosis, reduces proliferation, and suppresses tumor-induced angiogenesis. Over-expression and activity of PKC and PI3K/AKT are associated with poor prognosis and treatment resistance in NSCLC. This multicenter phase II trial of enzastaurin as second- and third-line treatment of NSCLC determined the rate of progression-free survival (PFS) at 6 months (mos). Secondary objectives included safety and the rate of overall survival (OS) at 12 mos. Methods: Eligibility included metastatic (stage IV and wet IIIB) NSCLC and prior platinum-based chemotherapy. Patients (pts) received 500 mg of oral enzastaurin, once daily, until disease progression or unacceptable toxicity occurred. All pts were eligible for 2nd or 3rd line treatment. Results: In the 54 pts enrolled [54% M, 46% F; median age: 63 (range: 43–82); 22.2% stage III, 77.8% stage IV, ECOG PS=2], adenocarcinoma was the most frequent diagnosis (67%). Prior therapies included radiotherapy (74%) and EGFR inhibitors (28%). At the final analysis, the median PFS was 1.9 mos (95% CI: 1.7–1.9), and the PFS rate at 6 mos was 14% (95% CI: 4.4%–23.6%). The median OS was 9.9 mos (95% CI: 6.5–14.6). The OS rate at 12 mos was 46.3% (95% CI: 32.1%–60.5%). Nineteen pts (35%) had stable disease (SD); none had a complete or partial response. Ten (19%) pts were on-study for =6 cycles, 3 of whom continued for >10 months. The most common toxicity, fatigue (grade =2, n=15), occurred within 1 week of enrollment and was not reported in pts with SD. Grade =3 toxicities observed were ataxia (n=1), fatigue (n=2), thrombo-embolism (n=1), and anemia (n=1). Two pts discontinued due to fatigue and dizziness. Five pts died on-study and 4 within 30 days of discontinuation due to PD. Post-study chemotherapy (n=28) included bevacizumab, erlotinib, pemetrexed, gemcitabine, cisplatinum and paclitaxel. Conclusion: Although no objective tumor responses occurred, 14% of the pts were progression-free at 6 months. Based on encouraging survival and tolerability data, further evaluation of enzastaurin as a single agent or in combination, is warranted in NSCLC.

No significant financial relationships to disclose.

A phase I study of intravenous tetra-O-methyl nordihydroguaiaretic acid in patients with refractory malignancy

3584

Background: Tetra-o-methyl nordihydroguaiaretic acid (terameprocol-also EM-1421 or M4N) is a semi-synthetic derivative of a naturally occurring plant lignan. Terameprocol blocks cell cycle progression by inhibiting expression of the Sp1-dependent cdk1 gene and promotes apoptosis by inhibiting survivin. Methods: A dose escalation, open-label study enrolled patients (pt) with malignancies refractory to surgery, radiation therapy, and/or chemotherapy. Terameprocol was administered daily by intravenous infusion for 5 days (d) every 28 d over 30 minutes, with dose escalation (100, 200, 375, 750, 1,500, 2,200, and 3,300 mg) in cohorts of 3–6 pt. Tumor measurement (CT and PET scans) was performed at baseline and every 2 to 4 cycles. Pt at the 2,200mg and 3,300mg doses had circulating tumor cells (CTC) measured prior to dosing. Pharmacokinetics (PK) was evaluated for the first 2 cycles. Results: Twenty nine pt (17 male), median age 61 years, with gynecological (21%), lung (17%), colorectal (17%), or other cancer (45%) were enrolled. All pt were evaluable for toxicity and 21 pt for efficacy. At the highest dose (3,300 mg/d), dose limiting toxicity (DLT) of metabolic acidosis/respiratory failure considered drug related was observed in 1 of 3 pt, and no additional pt was enrolled at this dose. The next lower dose cohort (2,200 mg/d) was expanded (11 pt) and no DLT has been observed. Best response by RECIST criteria included a partial response in 1 pt and stable disease in 6 pt. Three pt discontinued for reason other than progression, and 11 had progressive disease. Pharmacokinetics demonstrated dose linearity. The volume of distribution was 300–1,000 liters, and the half-life ∼ 20–30 hours. No obvious trend was seen in CTCs. Across all doses, 108 adverse events, with 10 severe events, were observed. Conclusions: Terameprocol is well tolerated up to a dose of 2,200 mg and warrants further evaluation. Expansion continues at this dose level. There is clinical benefit in this refractory population that warrants further investigation.

No significant financial relationships to disclose.