Abstract PD05-12: Combination of Notch Inhibitor MK-0752 and Endocrine Therapy for Early Stage ERα + Breast Cancer in a Presurgical Window Pilot Study

Background: Breast tumor initiating cells (TIC) use Notch receptors/ligands with other pathways for self renewal, resulting in tumor proliferation and progression. We showed that Notch inhibition with gamma secretase inhibitors (GSI) potentiates the effects of tamoxifen (tam) in xenografts (Rizzo et al. Cancer Res 2008). It is unknown whether GSIs plus endocrine therapy result in modulation of Notch and other proliferation markers in human breast cancer. Our objective was to add short exposure of the GSI MK-0752 to ongoing tam or letrozole (letr) during the presurgical window to determine 1) feasibility, 2) safety/tolerance, and 3) impact on biomarkers. We report the initial cohort of this pilot study (ClinTrials. gov NCT00756717).

Methods: Patients (pts) with early stage ERα + breast cancer were treated with 25 days of tam or letr. On day 15 MK-0752 was added to endocrine therapy (350 mg orally 3 days on, 4 days off, 3 days on), with definitive surgery day 25. Formalin fixed, paraffin embedded biopsies were obtained at baseline, day 14 and final surgery, with histologic confirmation of tumor content >50% and RNA extraction by standard methods. Q-PCR was done for Notch1, Notch3, Notch4, Deltex, Jagged1, c-myc, HEY1, HEY2, HES1, PS2, C-Myc, Cyclin A2, NOXA (pro-apoptotic protein), Ki67, Dicer-1, RPL13 (internal control). Ct averages for 3 replicates were used and mRNA levels were calculated by the 2ΔΔCt method. Baseline gene expression levels were used as comparators for days 14 and 25 levels in each pt. The first cohort of 10 pts was analyzed to determine if enough signals were present to justify expanding the cohort at this dose to 20 pts and possibly test a second cohort on an alternate MK-0752 dose/schedule. Results: The initial cohort of 10 pts completed all therapy (4 tam, 6 letr), all biopsies and definitive surgery on schedule. One other pt withdrew prior to starting MK-0752 due to hypertension. Toxicity was minimal: grade 1 periorbital edema/cough, nausea, and axillary paresthesias in 1 pt each; grade 1 facial rash, 2 pts; and grade 2 fatigue, 1 pt. There was no diarrhea or surgical complications. Significant changes occurred in molecular marker levels after MK-0752 plus tam/letr (day 25) vs. end of tam/letr alone (day 14) as follows: Ki67 mRNA decreased in 9/10 pts; Notch4 decreased, 10/10; NOXA increased, 6/10; and Notch1 decreased, 6/10. Other markers showed inter-individual variations and will be presented, along with results of the global gene expression profiling (in progress). Conclusions: The addition of a short exposure of the GSI MK-0752 to ongoing endocrine therapy was feasible, safe, and well tolerated in pts with ERα + early breast cancer prior to definitive surgery. It results in anti-proliferative and pro-apoptotic effects at the molecular level. Notch4, which plays a key role in breast TIC, was the most consistent molecular marker of response in this setting. This suggests a potential anti-TIC effect of this combination and a role in overcoming endocrine resistance. Accrual to the expanded cohort is underway. If findings are confirmed, the second study with alternate MK-0752 dose/schedule may commence. Funding: Swim Across America, Inc. (clinical trial costs); Merck (drug supply, profiling)

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr PD05-12.

A phase I and pharmacological study of MK-1775, a Wee1 tyrosine kinase inhibitor, in both monotherapy and in combination with gemcitabine, cisplatin, or carboplatin in patients with advanced solid tumors

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Background: MK-1775 is an inhibitor of Wee1, a kinase that phosphorylates CDC2 to inactivate the CDC2/cyclin B complex (regulating the G2 checkpoint). Since most human cancers harbor p53-dependent G1 checkpoint abnormalities, they are dependent on the G2 checkpoint. G2 checkpoint abrogation may therefore sensitize p53 deficient tumor cells to anti-cancer agents. Methods: This study is evaluating the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of MK-1775 administered as both monotherapy (MT) and combination therapy (CT) with gemcitabine (G), cisplatin (P), or carboplatin (C). PART 1 consists of a single dose of MK-1775 followed by 14 days observation. If well tolerated, the same pt continues on to one of three treatment arms in PART 2: a single lower dose of MK-1775 in combination with: 1) 1000 mg/m2 G, 2) 75 mg/m2 P or 3) C AUC 5. Maximum Tolerated Doses (MTDs) will be established for MK-1775 as both monotherapy and in combination. PD biomarkers include IHC analysis for pCDC2/CDC2 in plucked hair and skin biopsies, peripheral blood, and tumor biopsies. Wee1 gene expression signature is measured in plucked hair and tumor biopsies by qPCR. Results: To date, 37 pts (median age 61; up to 4 prior therapies) have been treated with MK-1775. 4 pts experienced DLT. One pt on G + 200mg MK-1775 had gr3 leucopenia and neutropenia; one pt on P + 200mg MK-1775 had gr3, fatigue, diarrhea and hypokalemia and another pt gr2 nausea/vomiting > 48hrs requiring hospitalization. One pt on C + 325mg MK-1775 was hospitalized for gr3 bilirubin. Linear PK was demonstrated at 100, 200, 325, 650 and 1300 mg MK-1775. Terminal T½ of MK-1775 was 7.6–12.2 hrs and Tmax was 1.0–6.0 hrs. Preliminary MTDs of MK-1775 in combination with G, C and P were 200, 325 and 200mg, respectively. Significant changes in Wee1 signature gene expression were observed in plucked hair. Of 28 evaluable pts, >50% regression of axillary lymphadenopathy was seen in 1 pt with melanoma on the P arm, and stable disease in 14 other pts (median duration). Conclusions: MK-1775 is a first in class Wee1 inhibitor that is well tolerated and shows promising anti-tumor activity in previously treated pts.

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Molecular targets of glioma invasion

Glioblastoma multiforme is the most common and lethal primary malignant brain tumor. Although considerable progress has been made in technical proficiencies of surgical and radiation treatment for brain tumor patients, the impact of these advances on clinical outcome has been disappointing, with median survival time not exceeding 15 months. Over the last 30 years, no significant increase in survival of patients suffering from this disease has been achieved. A fundamental source of the management challenge presented in glioma patients is the insidious propensity of tumor invasion into distant brain tissue. Invasive tumor cells escape surgical removal and geographically dodge lethal radiation exposure and chemotherapy. Recent improved understanding of biochemical and molecular determinants of glioma cell invasion provide valuable insight into the underlying biological features of the disease, as well as illuminating possible new therapeutic targets. These findings are moving forward to translational research and clinical trials as novel antiglioma therapies.

Migratory activity of human glioma cell lines in vitro assessed by continuous single cell observation

A new migration assay, the time-lapse individual cell migration assay (TIM-assay), was developed, which allows the observation of cells over 24 h under controlled conditions. Using this technique, the migratory behavior of 8 human glioblastoma cell lines in vitro was studied. Special features are simultaneous documentation of migratory parameters of individual cells, i.e., migration velocities and migration paths of individual cells. Migration velocity for cell populations of the same cell line ranged from 0 to 24 microm/h. The migration paths were examined for being directional. Two thirds of all cells showed directional migration. Migration paths were further classified according to visual judgements for being linear, oscillating or mixed. The migration index had a mean of 91%. The presented TIM-assay allows the assessment of several new parameters. that may be useful to identify subgroups of gliomas with different biological characteristics.

Glioma cell motility is associated with reduced transcription of proapoptotic and proliferation genes: a cDNA microarray analysis

Microarray analysis of complementary DNA (cDNA) allows large-scale, comparative, gene expression profiling of two different cell populations. This approach has the potential for elucidating the primary transcription events and genetic cascades responsible for increased glioma cell motility in vitro and invasion in vivo. These genetic determinants could become therapeutic targets. We compared cDNA populations of a glioma cell line (G112) exposed or not to a motility-inducing substrate of cell-derived extracellular matrix (ECM) proteins using two sets of cDNA microarrays of 5,700 and 7,000 gene sequences. The data were analyzed considering the level and consistency of differential expression (outliers) and whether genes involved in pathways of motility, apoptosis, and proliferation were differentially expressed when the motility behavior was engaged. Validation of differential expression of selected genes was performed on additional cell lines and human glioblastoma tissue using quantitative RT-PCR. Some genes involved in cell motility, like tenascin C, neuropilin 2, GAP43, PARG1 (an inhibitor of Rho), PLCy, and CD44, were over expressed; other genes, like adducin 3y and integrins, were down regulated in migrating cells. Many key cell cycle components, like cyclin A and B, and proliferation markers, like PCNA, were strongly down regulated on ECM. Interestingly, genes involved in apoptotic cascades, like Bcl-2 and effector caspases, were differentially expressed, suggesting the global down regulation of proapoptotic components in cells exposed to cell-derived ECM. Overall, our findings indicate a reduced proliferative and apoptotic activity of migrating cells. cDNA microarray analysis has the potential for uncovering genes linking the phenotypic aspects of motility, proliferation, and apoptosis.