First-in-human phase 0 study of 111In-CHX-A"-DTPA trastuzumab for HER2 tumor imaging

Introduction:

Tumors over-expressing the human epithelial receptor 2 (HER2) or exhibiting amplification or mutation of its proto-oncogene have a poorer prognosis. Using trastuzumab and/or other HER2 targeted therapies can increase overall survival in patients with HER2(+) tumors making it critical to accurately identify patients who may benefit. We report on a Phase 0 study of the imaging agent, ¹¹¹In-CHX-A”-DTPA trastuzumab, in patients with known HER2 status to evaluate its safety and biodistribution and to obtain preliminary data regarding its ability to provide an accurate, whole-body, non-invasive means to determine HER2 status.

Methods:

¹¹¹In-CHX-A”-DTPA trastuzumab was radiolabeled on-site and slowly infused into 11 patients who underwent single (n=5) or multiple (n=6) ɣ-camera (n=6) and/or SPECT (n=8) imaging sessions.

Results:

No safety issues were identified. Visual and semi-quantitative imaging data were concordant with tissue HER2 expression profiling in all but 1 patient. The biodistribution showed intense peak liver activity at the initial imaging timepoint (3.3h) and a single-phase clearance fit of the average time-activity curve (TAC) estimated t_1/2=46.9h (R²=0.97; 95%CI 41.8 to 53h). This was followed by high gastrointestinal (GI) tract activity peaking by 52h. Linear regression predicted GI clearance by 201.2h (R² =0.96; 95%CI 188.5 to 216.9h). Blood pool had lower activity with its maximum on the initial images. Non-linear regression fit projected a t_1/2=34.2h (R² =0.96; 95%CI 25.3 to 46.3h). Assuming linear whole-body clearance, linear regression projected complete elimination (x-intercept) at 256.5hr (R²=0.96; 95%CI 186.1 to 489.2h).

Conclusion:

¹¹¹In-CHX-A”-DTPA trastuzumab can be safely imaged in humans. The biodistribution allowed for visual and semiquantitative analysis with results concordant with tissue expression profiling in 10 of 11 patients. Advances in Knowledge and Implications for Patient Care Using readily available components and on-site radiolabeling ¹¹¹In-CHX-A”-DTPA trastuzumab SPECT imaging may provide an economical, non-invasive means to detect HER2 over-expression.

A Phase II Study of 5-AZA-2'Deoxycytidine (Decitabine) in Hormone Independent Metastatic (D2) Prostate Cancer

Aims and Background

Decitabine (5-aza-2′-deoxycytidine) is an S-phase-specific pyrimidine analog with hypomethylation properties. In laboratory models of prostate cancer (PC-3 and DU-145), decitabine induces cellular differentiation and enhanced expression of genes involved in tumor suppression, immunogenicity, and programmed cell death.

Methods

We conducted a phase II study of decitabine in 14 men with progressive, metastatic prostate cancer recurrent after total androgen blockade and flutamide withdrawal. Decitabine was administered at a dose of 75 mg/m2/dose IV as a 1 hour infusion every 8 hours for three doses. Cycles of therapy were repeated every 5 to 8 weeks to allow for resolution of toxicity.

Results

Two of 12 patients evaluable for response had stable disease with a time to progression of more than 10 weeks. This activity was seen in 2 of 3 African-American patients. Toxicity was similar to previously reported experience. No significant changes in urinary concentrations of the angiogenic factor bFGF, a potential biomarker of tumor activity, were identified over time in 7 unselected patients with progressive disease.

Conclusions

We conclude that decitabine is a well tolerated regimen with modest clinical activity against hormone-independent prostate cancer. Further investigations in patients of African-American origin may be warranted.

Abstract P1-01-01: The blood-Tumor barrier as a therapeutic target to improve therapy of brain metastases of breast cancer

Objectives: Brain metastases of breast cancer demonstrate low and heterogeneous levels of permeability to drugs in mouse models and human craniotomies. The Blood-Brain Barrier (BBB), the protective lining of CNS blood vessels, impedes drug entry into the normal brain. When a metastasis forms, the BBB is locally altered to a poorly characterized Blood-Tumor Barrier (BTB). Quantitative experimental models indicate that most brain metastases have increased permeability over the normal BBB, but BTB permeability is both heterogeneous and ˜2 logs less than that of systemic metastases. We have interrogated three hematogenous models of brain metastasis of breast cancer to ask (1) whether the BTB is an ordered structure or a random breakdown of the BBB; (2) among brain metastases, whether consistent differences underlie the BTBs of lesions with low- and high permeabilities to fluorescent markers and drugs; (3) if alterations in BTB composition can functionally change its permeability. Our long term goal is to enhance uptake of drugs into brain metastases to effective levels.

Results: When uninvolved brain was compared with any brain metastasis, alterations in endothelial, pericytic, astrocytic, and microglial components of the BBB were observed. Both the pericyte and astrocyte components of the BTB were consistently altered with increased permeability: When metastases with relatively low and high permeability were compared, increased expression of a desmin+ subpopulation of pericytes was associated with higher permeability (231-BR6 P=0.0002; JIMT-1-BR3 P = 0.004; SUM190-BR3 P=0.008). A trend toward reduced CD13+ pericytes was observed in highly permeable metastases (231-BR6 P =0.014; JIMT-1-BR3 P =0.002, SUM190-BR3, NS). For GFAP+ astrocytes in the neuroinflammatory response surrounding metastases, no overall difference in cell number was observed between low and high permeability lesions. However, gene expression profiling of laser capture microdissected low and high permeabililty lesions demonstrated overexpression of the sphingosine-1 phosphate receptor 3 (S1P3) in the astrocytes of highly permeable lesions, which was confirmed at the protein expression level in all three models (231-BR6 P=0.034; JIMT-1-BR3 P = 0.01; SUM190-BR3 P=0.016). Inhibition of S1P3 via S1PR3 shRNA or a selective antagonist (TY-52156) functionally tightened the BTB in an in vitro model. Administration of TY-52156 to mice harboring 231-BR6 brain metastases had no effect on metastasis number, but decreased uptake of Texas Red Dextran dye into metastases (P=0.016). S1P3 mediated its effects on BTB permeability through astrocytic secretion of IL-6 and CCL2, which altered endothelial expression and localization of adhesive proteins, a potentially translatable pathway. Both desmin+ pericytes and S1P3+ astrocytes are present in human craniotomy specimens.

Conclusions: These experiments demonstrate that the BTB is a structure with consistent properties, and that further consistent changes underlie the transition from a low to high permeability BTB. While proof of principle, S1P3 inhibition studies indicate that the BTB permeability can be functionally modulated in vivo.

Citation Format: Steeg PS, Lyle TR, Paranjapee A, Lockman PR, Duchnowska R, Brastianos PK, Peer C, Figg WD, Pauly GT, Schneider JP, Smith QR, Gril B. The blood-Tumor barrier as a therapeutic target to improve therapy of brain metastases of breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-01-01.

Targeting the microenvironment of pancreatic cancer: overcoming treatment barriers and improving local immune responses

Historically, patients diagnosed with metastatic pancreatic cancer have faced a grim prognosis. The survival benefit seen with systemic chemotherapies and even combinations thereof have been disappointing. However, growing data suggest that the microenvironment of pancreatic cancer may be contributing to this poor prognosis. This microenvironment has a dense fibrotic stroma, and is hypoxic and highly immunosuppressive, all of which pose barriers to treatment. Newer strategies looking to disrupt the fibrotic stroma, target hypoxic areas, and improve local immune responses in the tumor microenvironment are currently undergoing clinical evaluation and seem to offer great promise. In addition to these therapies, preclinical work evaluating novel cytotoxic agents including nanoparticles has also been encouraging. While much research still needs to be done, these strategies offer new hope for patients with pancreatic cancer.

Modulation of tumor eIF4E by antisense inhibition: A phase I/II translational clinical trial of ISIS 183750-an antisense oligonucleotide against eIF4E-in combination with irinotecan in solid tumors and irinotecan-refractory colorectal cancer

The eukaryotic translation initiation factor 4E (eIF4E) is a potent oncogene that is found to be dysregulated in 30% of human cancer, including colorectal carcinogenesis (CRC). ISIS 183750 is a second-generation antisense oligonucleotide (ASO) designed to inhibit the production of the eIF4E protein. In preclinical studies we found that EIF4e ASOs reduced expression of EIF4e mRNA and inhibited proliferation of colorectal carcinoma cells. An additive antiproliferative effect was observed in combination with irinotecan. We then performed a clinical trial evaluating this combination in patients with refractory cancer. No dose-limiting toxicities were seen but based on pharmacokinetic data and tolerability the dose of irinotecan was reduced to 160 mg/m(2) biweekly. Efficacy was evaluated in 15 patients with irinotecan-refractory colorectal cancer. The median time of disease control was 22.1 weeks. After ISIS 183750 treatment, peripheral blood levels of eIF4E mRNA were decreased in 13 of 19 patients. Matched pre- and posttreatment tumor biopsies showed decreased eIF4E mRNA levels in five of nine patients. In tumor tissue, the intracellular and stromal presence of ISIS 183750 was detected by IHC in all biopsied patients. Although there were no objective responses stable disease was seen in seven of 15 (47%) patients who were progressing before study entry, six of whom were stable at the time of the week 16 CT scan. We were also able to confirm through mandatory pre- and posttherapy tumor biopsies penetration of the ASO into the site of metastasis.

A phase II study of TRC105 in patients with hepatocellular carcinoma who have progressed on sorafenib

BACKGROUND

Endoglin is an endothelial cell membrane receptor essential for angiogenesis and highly expressed on the vasculature of many tumor types, including hepatocellular carcinoma (HCC). TRC105 is a chimeric IgG1 anti-CD105 monoclonal antibody that inhibits angiogenesis and tumor growth by endothelial cell growth inhibition, ADCC and apoptosis, and complements VEGF inhibitors.

OBJECTIVE

The aim of this phase II study was to evaluate the efficacy of anti-endoglin therapy with TRC105 in patients with advanced HCC, post-sorafenib.

METHODS

Patients with HCC and compensated liver function (Childs-Pugh A/B7), ECOG 0/1, were enrolled to a single-arm, phase II study of TRC105 15 mg/kg IV every two weeks. Patients must have progressed on or been intolerant of prior sorafenib. A Simon optimal two-stage design was employed with a 50% four-month PFS target for progression to the second stage. Correlative biomarkers evaluated included DCE-MRI as well as plasma levels of angiogenic biomarkers and soluble CD105.

RESULTS

A total accrual of 27 patients was planned. However, because of lack of efficacy and in accordance with the Simon two-stage design, 11 patients were enrolled. There were no grade 3/4 treatment-related toxicities. Most frequent toxicities were headache (G2; N = 3) and epistaxis (G1; N = 4). One patient had a confirmed partial response by standard RECIST criteria and biologic response on DCE-MRI but the four-month PFS was insufficient to proceed to the second stage of the study.

CONCLUSIONS

TRC105 was well tolerated in this HCC population following sorafenib. Although there was evidence of clinical activity, this did not meet prespecified criteria to proceed to the second stage. TRC105 development in HCC continues as combination therapy with sorafenib.

Angiogenesis in spontaneous tumors and implications for comparative tumor biology

Blood supply is essential for development and growth of tumors and angiogenesis is the fundamental process of new blood vessel formation from preexisting ones. Angiogenesis is a prognostic indicator for a variety of tumors, and it coincides with increased shedding of neoplastic cells into the circulation and metastasis. Several molecules such as cell surface receptors, growth factors, and enzymes are involved in this process. While antiangiogenic therapy for cancer has been proposed over 20 years ago, it has garnered much controversy in recent years within the scientific community. The complex relationships between the angiogenic signaling cascade and antiangiogenic substances have indicated the angiogenic pathway as a valid target for anticancer drug development and VEGF has become the primary antiangiogenic drug target. This review discusses the basic and clinical perspectives of angiogenesis highlighting the importance of comparative biology in understanding tumor angiogenesis and the integration of these model systems for future drug development.

The CYP2C19*17 variant is not independently associated with clopidogrel response

BACKGROUND

Cytochrome P450 2C19 (CYP2C19) is the principal enzyme responsible for converting clopidogrel into its active metabolite, and common genetic variants have been identified, most notably CYP2C19*2 and CYP2C19*17, that are believed to alter its activity and expression, respectively.

OBJECTIVE

We evaluated whether the consequences of the CYP2C19*2 and CYP2C19*17 variants on clopidogrel response were independent of each other or genetically linked through linkage disequilibrium (LD).

PATIENTS/METHODS

We genotyped the CYP2C19*2 and CYP2C19*17 variants in 621 members of the Pharmacogenomics of Anti-Platelet Intervention (PAPI) Study and evaluated the effects of these polymorphisms singly and then jointly, taking into account LD, on clopidogrel prodrug level, clopidogrel active metabolite level, and adenosine 5'-diphosphate (ADP)-stimulated platelet aggregation before and after clopidogrel exposure.

RESULTS

The CYP2C19*2 and CYP2C19*17 variants were in LD (|D'| = 1.0; r(2)  = 0.07). In association analyses that did and did not account for the effects of CYP2C19*17, CYP2C19*2 was strongly associated with levels of clopidogrel active metabolite (β = -5.24, P = 3.0 × 10(-9) and β = -5.36, P = 3.3 × 10(-14) , respectively) and posttreatment ADP-stimulated platelet aggregation (β = 7.55, P = 2.9 × 10(-16) and β = 7.51, P = 7.0 × 10(-15) , respectively). In contrast, CYP2C19*17 was marginally associated with clopidogrel active metabolite levels and ADP-stimulated platelet aggregation before (β = 1.57, P = 0.04 and β = -1.98, P = 0.01, respectively) but not after (β = 0.40, P = 0.59 and β = -0.13, P = 0.69, respectively) adjustment for the CYP2C19*2 variant. Stratified analyses of CYP2C19*2/CYP2C19*17 genotype combinations revealed that CYP2C19*2, and not CYP2C19*17, was the primary determinant in altering clopidogrel response.

CONCLUSIONS

Our results suggest that CYP2C19*17 has a small (if any) effect on clopidogrel-related traits and that the observed effect of this variant is due to LD with the CYP2C19*2 loss-of-function variant.

OATP1B1 polymorphism as a determinant of erythromycin disposition

Previous studies have demonstrated that the pharmacokinetic profile of erythromycin, a probe for CYP3A4 activity, is affected by inhibitors or inducers of hepatic solute carriers. We hypothesized that these interactions are mediated by OATP1B1 (gene symbol, SLCO1B1), a polypeptide expressed on the basolateral surface of hepatocytes. Using stably transfected Flp-In T-Rex293 cells, erythromycin was found to be a substrate for OATP1B1*1A (wild type) with a Michaelis-Menten constant of ~13 µmol/l, and that its transport was reduced by ~50% in cells expressing OATP1B1*5 (V174A). Deficiency of the ortholog transporter Oatp1b2 in mice was associated with a 52% decrease in the metabolic rate of erythromycin (P = 0.000043). In line with these observations, in humans the c.521T>C variant in SLCO1B1 (rs4149056), encoding OATP1B1*5, was associated with a decline in erythromycin metabolism (P = 0.0072). These results suggest that impairment of OATP1B1 function can alter erythromycin metabolism, independent of changes in CYP3A4 activity.

Effect of ABCC2 (MRP2) transport function on erythromycin metabolism

The macrolide antiobiotic erythromycin undergoes extensive hepatic metabolism and is commonly used as a probe for cytochrome P450 (CYP) 3A4 activity. By means of a transporter screen, erythromycin was identified as a substrate for the transporter ABCC2 (MRP2) and its murine ortholog, Abcc2. Because these proteins are highly expressed on the biliary surface of hepatocytes, we hypothesized that impaired Abcc2 function may influence the rate of hepatobiliary excretion and thereby enhance erythromycin metabolism. Using Abcc2 knockout mice, we found that Abcc2 deficiency was associated with a significant increase in erythromycin metabolism, whereas murine Cyp3a protein expression and microsomal Cyp3a activity were not affected. Next, in a cohort of 108 human subjects, we observed that homozygosity for a common reduced-function variant in ABCC2 (rs717620) was also linked to an increase in erythromycin metabolism but was not correlated with the clearance of midazolam. These results suggest that impaired ABCC2 function can alter erythromycin metabolism, independent of changes in CYP3A4 activity.

A phase I study of TRC105 (anti-CD105 monoclonal antibody) in metastatic castration-resistant prostate cancer (mCRPC)

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Background: TRC105 is a human/murine chimeric IgG1 monoclonal antibody to CD105 (endoglin) that inhibits angiogenesis and tumor growth through inhibition of endothelial cell (EC) proliferation, antibody-dependent cellular cytotoxicity and induction of apoptosis. CD105 is highly expressed on proliferating vascular ECs. Preclinical and clinical evidence demonstrates an important role for angiogenesis in mCRPC biology.

Methods: The primary objective is to evaluate safety and identify the maximum tolerable dose of TRC105. Secondary objectives include the assessment of TRC105 pharmacokinetics, PSA response rate and overall response rate (ORR). Eligibility requires ECOG performance status (PS) ≤ 2 and progressive mCRPC. Three cohorts of 3-6 patients receive TRC105 at doses of 1, 3 or 10 mg/kg IV over 1–4 hours every 2 weeks of a 4 week cycle. Premedications are dexamethasone, acetaminophen, famotidine, and diphenhydramine. PSA is evaluated prior to each treatment and response is assessed every 2 cycles with imaging studies.

Results: Eight patients are enrolled in cohorts 1–3. Median age is 65 (range 47–84), ECOG PS 1 (1–2), Gleason score 8 (6–10), on–study PSA 201 (0.10 – 3,373), and number of prior therapies after gonadotropin-releasing hormone agonist or anti-androgen therapy 2.5 (0–6). Median time on study is 14 weeks (7–16). Dose-limiting toxicity was not observed. Grade 1 to 2 infusion reactions occurred in 4 patients. PSA declines were seen in both patients in cohort 3 (26% and 51% from baseline); each had progressed on docetaxel and at least one second-line agent. Five of 6 evaluable patients with measurable soft tissue disease achieved stable disease (2 in cohort 1, 2 in cohort 2 and 1 in cohort 3); the latter 3 patients in cohorts 2 and 3 remain on study.

Conclusions: TRC105 is tolerated at doses up to 10 mg/kg every 2 weeks with early evidence of clinical activity in patients with mCRPC. Accrual is ongoing to evaluate higher doses and more frequent dosing.

No significant financial relationships to disclose.

Phase II trial of bevacizumab (A), lenalidomide (R), docetaxel (D), and prednisone (P) in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC)

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Background: Angiogenesis appears to play critical role in the progression of mCRPC. Previously we have shown anti-tumor activity in mCRPC with the combination of D, thalidomide (T), A and P (Ning JCO 2010). We hypothesized that combining R, an analogue of T, with A, D and P would have a more favorable toxicity profile and similar anti-tumor activity.

Methods: All pts had chemotherapy-naïve progressive mCRPC. 6 pts were treated with R at 15 and 20 mg prior to doses at 25 mg. Treatment is 75 mg/m2 D, 15 mg/kg A every 21 days as one cycle (C), plus 25 mg R for 14 days with daily 10 mg P and enoxaparin. After grade 3 neutropenia was seen in > 80% of pts in all cohorts, the protocol was amended to include prophylactic pegfilgrastim. PSA is tested each C with imaging after C2 and then every 3C. Dental exams with mandible CT's are at baseline, after C5, and then every 6C or earlier if needed.

Results: 28 of a planned 51 pts have been enrolled. Pt characteristics include: median age 65.5 [51-78], Gleason score 8 [67.9% 8-10, 32.1% 6-7], on-study PSA 94.3 ng/mL [9.2-3520], and pre-study PSA doubling time 1.43 months [0.52-4.07]. Median C number was 8 [1-21]. 2/28 pts were off study due to clinical or radiographic progression. 26 pts remain on study. 22/24 (91.7%) and 20/24 (83.3%) pts who have completed ≥ 4C had PSA- decline of ≥ 50% and ≥ 75%, respectively. 14 pts with measurable disease were evaluable with 2 CRs (1 unconfirmed), 9 PRs (2 unconfirmed), and 3 SDs (a 78.6% overall RR). Grade ≥ 3 toxicities include neutropenia (16/28), anemia (6/28), thrombocytopenia (3/28), hypertension (1/28), and infection (2/28). 1/28 pts had febrile neutropenia. 8/28 pts (28.6%) developed grade 2 osteonecrosis of the jaw (ONJ), defined as bone death on dental exam, higher than 18.3% as reported by Ning. 5/8 had concomitant and 2/8 pts had history of bisphosphonate use.

Conclusions: Combined therapy with anti-angiogenic agents R and A, plus D and P is associated with high response rates, 91.7% in PSA and 78.6% in measurable disease in mCRPC pts, with manageable toxicities. Further study is underway to characterize the activity and to explore the high incidence of ONJ, including the possibility of ascertainment bias.

No significant financial relationships to disclose.

A pharmacogenetic study of docetaxel and thalidomide in patients with castration-resistant prostate cancer using the DMET genotyping platform

The anticancer agent docetaxel shows significant inter-individual variation in its pharmacokinetic and toxicity profile. Thalidomide is an active anticancer agent and also shows wide pharmacological variation. Past pharmacogenetic research has not explained this variation. Patients with prostate cancer enrolled in a randomized phase II trial using docetaxel and thalidomide versus docetaxel alone were genotyped using the Affymetrix DMET 1.0 platform, which tests for 1256 genetic variations in 170 drug disposition genes. Genetic polymorphisms were analyzed for associations with clinical response and toxicity. In all, 10 single-nucleotide polymorphisms (SNPs) in three genes were potentially associated with response to therapy: peroxisome proliferator-activated receptor-delta (PPAR-delta), sulfotransferase family, cytosolic, 1C, member 2 (SULT1C2) and carbohydrate (chondroitin 6) sulfotransferase 3 (CHST3). In addition, 11 SNPs in eight genes were associated with toxicities to treatment: spastic paraplegia 7 (pure and complicated autosomal recessive) (SPG7), CHST3, cytochrome P450, family 2, subfamily D, polypeptide 6 (CYP2D6), N-acetyltransferase 2 (arylamine N-acetyltransferase) (NAT2), ATP-binding cassette, sub-family C (CFTR/MRP), member 6 (ABCC6), ATPase, Cu++ transporting, alpha polypeptide (ATP7A), cytochrome P450, family 4, subfamily B, polypeptide 1 (CYP4B1) and solute carrier family 10 (sodium/bile acid cotransporter family), member 2 (SLC10A2). Genotyping results between drug metabolizing enzymes and transporters (DMET) and direct sequencing showed >96% of concordance. These findings highlight the role that non-CYP450 metabolizing enzymes and transporters may have in the pharmacology of docetaxel and thalidomide.

A phase I study of nelfinavir, an FDA approved HIV protease inhibitor, in adults with refractory solid tumors

2583

Background: Preclinical studies show that HIV protease inhibitors such as nelfinavir (N) have dose- dependent, pleiotropic anti-cancer activities. However, the maximum tolerated dose (MTD) of N has not been established in humans. Methods: Pts were treated on a modified Fibonacci dose-escalation scheme with a twice daily oral dose of N starting at the FDA approved dose of 1250 mg bid on a 21-day cycle. Patients with refractory solid tumors, ECOG PS < 2, and adequate organ function were eligible. Therapy continued until MTD or disease progression. PBMCs as well as optional tumor biopsies were collected for Akt inhibition and expression of markers of ER stress (ERS). Results: 14 patients have been enrolled. Of the 11 evaluable for toxicity, there were 10 men, 10 Caucasians, and 1 African American (median age 63 years (range 24 - 77)). Tumor types included NSCLC (3), SCLC (2), thyroid (3), pancreatic (1), colorectal (1), and renal cell (1). Median number of prior systemic therapies was 2 (range, 1 - 6). There have been no grade 4 or 5 toxicities. We observed 12 grade 3 toxicities that were asymptomatic laboratory abnormalities. The most prevalent toxicities were ALT transaminitis (5 events in 8 subjects in dose level ((DL) 2, 3, 4), AST transaminitis (4 events in 8 subjects in DL 2, 4), diarrhea (8 events in 5 subjects in DL 2, 3, 4), and hyperglycemia (5 events in 5 subjects in DL 1, 2, 3). Enrollment continues at DL 4 (3125 mg twice daily). There have been no responses. Two subjects with lung cancer had stable disease for 9 weeks. Pharmacokinetic data revealed median Cmax of 2,461.5 ng/ml (DL1), 11,809 ng/ml (DL2), 11,576 ng/ml (DL3), and 11,986 ng/ml (DL4), occurring 4 hours after an oral dose. There was no relationship between the drug levels and albumin levels. Akt inhibition and increased expression of markers of ERS and apoptosis have been observed in PBMCs from week 1 in the majority of patients at every dose level, but there was no correlation with clinical response. Conclusions: N appears to be well tolerated in subjects with advanced solid tumors at 2.5 times the FDA approved dose. AUC data suggest that there may be only minimal increases in plasma drug concentrations with doses above 1875 mg twice daily.

No significant financial relationships to disclose.

Cediranib (AZD2171) in docetaxel-resistant, castration-resistant prostate cancer (CRPC)

5141

Background: There is no standard therapy for prostate cancer patients who have progressed following docetaxel therapy. VEGF is implicated in tumor blood vessel formation and in disease progression in several solid tumors. Cediranib is an oral, small molecule inhibitor of receptor tyrosine kinases which influence VEGF. Methods: Patients must have clinical and/or radiographic evidence of progression on docetaxel with no limit on the number of prior chemotherapy regimens or radioisotopes. The starting dose is 20 mg daily, imaging is every 2 months. The primary objective is a 30% 6 month probability of progression free survival as determined by clinical (not by PSA rise alone) and radiographic criteria Simon two stage optimal design is being utilized with twelve patients enrolled in the first cohort. If 2 or more patients are progression-free at 6 months, the cohort will be expanded to 35 evaluable patients. Patients receiving cediranib were scanned by DCE-MRI pre- and post-treatment. A two compartment model was used to analyze the volume transfer. Results: Thirty-four of a planned 35 patients have been enrolled and 4 remain on active treatment (2–7 months). There have been 13 of 23 evaluable patients with tumor shrinkage and 4 have met the criteria for partial response. Decreases in lymph node metastases as well as in lung, liver and bone lesions have occurred. PSA levels have not corresponded well with imaging responses. Adverse events have been similar to other drugs in this class including hypertension, dysphonia and fatigue. Grade 3 toxicities included vomiting (2), prolonged QTc interval (1) and muscle weakness (3), weight loss (3), dehydration (4), fatigue (6), hypoxia (1), renal failure (1), transaminitis (3), and anorexia (1). There have been 30 patients who were evaluated by DCE-MRI. Targeted lesions included bone (17) and soft tissue (15). Conclusions: The safety profile and early activity makes cediranib a promising drug in CRPC post docetaxel. Preliminary data suggests that cediranib does have direct effect on the microcirculation and vasculature. Additional accrual is required to better characterize the response rate, the discrepancy between PSA and standard imaging changes and establish evidence of clinical correlation for DCE-MRI.

No significant financial relationships to disclose.

Translational proof of mechanism (PoM) for sorafenib with bevacizumab: Endpoint analysis and clinical activity

3574

Background: We hypothesized that molecular targeting of tumor and its microenvironment with rational combination therapy would yield improved outcome. Bevacizumab (B) is a monocolonal antibody to vascular endothelial growth factor (VEGFF) and sorafenib (S) is a small molecule inhibitor of the VEGF receptor-2 and RAF-kinase.We have previously reported that S 200mg bid with B 5mg/kg q2wk resulted in partial responses and prolonged disease stabilization (ovarian cancers, renal cell cancer, leiomyosarcoma). Serial tumor biopsies were obtained for translational proof of mechanism analysis. Methods: Percutaneous core biopsies of metastatic sites were obtained at baseline, after 2wk of S (group A) or B (group B), and at 6wks (2 wk into S+B combination therapy). Tissue was used for: lysate array (TLA) proteomic analysis of signaling proteins, IHC for CD31, VEGF, and Ki67, Raf/Ras mutation, and SNP analysis. Results: 18 sets of 3 biopsies were obtained, assessed for morphologic response (MR; decrease to <60% viable tumor seen), and processed for TLA and IHC. 11 pts had morphologic response including all 4 PR and 6/12 SD pts. Greater reduction in change in phospho(p)-ERK was seen at 2wk in group A pts (starting with sorafenib only) (p = 0.003). 9/11 MR pts had inhibition of ERK or AKT activation (p < 0.03). OvCa pts were more likely to have reduction in bRaf (p = 0.02). Pts in group B (starting with bevacizumab only) had lower microvessel density as measured by CD31 IHC (p = 0.05) at 2 wks; there was also a trend to lower VEGF expression by IHC in that group.These effects were muted at time 3, after combination treatment. No relationships to clinical outcomes were found, every pt had at least 1SNP in >1 tested gene; there were no Ras mutations and 1 V600KRaf mutation . Conclusions: These exploratory results demonstrate proof of mechanism in the tumor and its microenvironment for the combination of S and B. Randomization of initial exposure for the first 4 wks allowed interrogation of the role of the independent agents; the Raf/ERK axis was inhibited by S treatment first and there was reduction in tissue angiogenesis markers with B first. The molecularly targeted combination of sorafenib and bevacizumab is biologically active and on target. Phase II studies in multiple tumor types are ongoing.

No significant financial relationships to disclose.

Modulation of erlotinib pharmacokinetics in mice by a novel cytochrome P450 3A4 inhibitor, BAS 100

Administration of BAS 100, a novel mechanism-based CYP3A4 inhibitor isolated from grapefruit juice, resulted in a 2.1-fold increase in erlotinib exposure following oral administration to wild-type and humanised CYP3A4 transgenic mice. This study illustrates the potential of BAS 100 to increase the low and variable oral bioavailability of erlotinib in cancer patients.

Osteonecrosis of the jaw (ONJ) in androgen-independent prostate cancer (AIPC) patients receiving ATTP (bevacizumab, docetaxel, thalidomide, and prednisone)

19594

Background: ONJ has been associated with IV bisphosphonate use in cancer patients (pts) and chemotherapy may be an additional risk factor. ONJ is believed to result from localized vascular insufficiency due to faulty bone remodeling. ONJ incidence in pts not receiving chemotherapy (e.g. Paget's disease) is reportedly only 0.8%; prostate cancer pts have an incidence of 6.5%. Methods: We reviewed data from pts with advanced AIPC who developed ONJ while being treated on a Phase II study of ATTP. Results: Six of 36 (17%) pts treated with ATTP had ONJ confirmed by oral surgery. Four of the 6 pts presented with pain and, in five, the ONJ was mandibular in location. All pts were treated conservatively with either sequestrectomy or oral cleansing with chlorhexidine. All pts had been treated monthly with IV zoledronic acid (ZA). The mean duration of ZA use before diagnosis of ONJ was 20 months (mos). One patient had been treated with oral alendronate for 3 years and then developed ONJ after 5 mos of ZA. Of the 36 pts on-study, previous dental history could be verified in 24 pts. ONJ was diagnosed in 4 of the 5 pts with a prior dental infection or invasive dental procedure. Pts received an average of 11 cycles of ATTP before ONJ was diagnosed. All pts with ONJ had received full doses of bevacizumab and most had received full doses of all medications for all cycles. Conclusions: The possibility exists that the risk for ONJ may be higher with specific chemotherapy regimens, particularly those that include steroids or anti-angiogenic agents. However, at this time prior dental infections or procedures remain the greatest known risk factor. It is also possible that the relatively high incidence of ONJ in prostate cancer patients may reflect increased awareness in this population. Randomized phase III trials in AIPC, specifically addressing the incidence of ONJ, are needed to determine whether specific chemotherapy regimens are associated with an increased risk of this complication.

No significant financial relationships to disclose.

A phase II trial of thalidomide, bevacizumab, and docetaxel in patients (pts) with metastatic androgen-independent prostate cancer (AIPC)

5114

Background: Angiogenesis plays a vital role in the progression of prostate cancer. Antiangiogenic agents thalidomide (T) and bevacizumab (Bv) may enhance docetaxel (Doc) activity in metastatic AIPC. However, T and Bv have different antiangiogenic mechanisms. Since tumor angiogenesis is a complex interplay of multiple angiogenic factors, we reasoned that combination of mechanistically different antiangiogenic agents T and Bv with Doc might be associated with an adequately high and durable PSA response to merit further study. Methods: Pts are required to have progressive metastatic AIPC and no prior chemotherapy for AIPC. Treatment consists of Doc 75 mg/m2 plus Bv 15 mg/kg day 1, q 21 days as a cycle (C), plus T 200 mg qhs and prednisone 10 mg qd. Enoxaparin is used for thrombosis prevention and pegfilgrastim initiated after detection of grade ≥3 neutropenia. PSA is assayed q C and staging studies are done at C 0, C 2, & then q 3 Cs. Results: 39 pts were enrolled, median age 66 [54–79], Gleason score 8 [74% Gs 10∼8, 26% Gs 7∼6], on-study PSA 92 ng/ml [5.9–4399] and pre-study PSA doubling time 1.6 months [0.3–18.2, 87 % <3 months]. Median treatment Cs is 14 [1- 28]. 34 pts (87%) had PSA declines of ≥50%, with median ≥50% PSA-duration 12 Cs [0∼28]. 3 pts have PSA declines around 40% and 2 stable. 26 pts (67%) had >80% PSA declines. 17 pts with measurable disease were evaluable: 1 CR, 9 PR, & 7 SD, with 59% ORR. Significant toxicities: febrile neutropenia (5/39), syncope (4/39), colon perforation or fistula (2/39), grade 3 bleeding (2/39), thrombosis (2/39). Conclusions: This trial is the first study to combine antiangiogenic agents of different mechanisms with Doc in metastatic AIPC. Most of the accrued patients have unfavorable characteristics as evidenced by a high Gleason score and a short PSA doubling time. However, the combination of T and Bv with Doc appears to result in both a high durable PSA decline rate (87%) and a high response in measurable disease (59%) with acceptable toxicities.

No significant financial relationships to disclose.

A pharmacogenetic study of docetaxel and thalidomide in patients with androgen-independent prostate cancer (AIPC) using targeted human DMET genotyping platform

3580

Background: Pharmacogenetic research holds the promise of individualizing cancer therapy by reducing inter-individual variability in drug response, thus enhancing efficacy and reducing toxicity. Past research has been limited due to the lack of a robust genotyping platform that can screen for single nucleotide polymorphisms (SNPs) in the dozens of genes known to be involved in drug disposition. We pilot tested the new Affymetrix Targeted Human Drug Metabolizing Enzymes and Transporter (DMET) 1.0 panel in an exploratory study of docetaxel and thalidomide. The DMET 1.0 panel tests for 1,229 genetic variations in 169 drug disposition genes, including 49 CYP450 genes, 73 non-CYP genes, and 47 transporters. Methods: DNA samples from 47 patients with AIPC enrolled in a randomized phase II trial using docetaxel and thalidomide vs. docetaxel alone were genotyped using the DMET 1.0 panel. Patients’ response was determined using RECIST criteria. Toxicities were graded using the NCI-CTC, and patients were identified if they experienced grade 3 or 4 toxicity. Given the distinct side effect profiles of these two drugs, specific toxicities were assigned as being due to either docetaxel or thalidomide. An association between the SNP parameters and clinical response or toxicity was tested using Mehta’s modification to Fisher’s exact test. Reported results were limited to those where p<0.01. Results: Six SNPs in three genes were associated with response to therapy: PPAR-delta (p=0.0011), SULT1C2 (p=0.0083), and CHST3 (4 SNPs, p=0.0001 to 0.0034). For toxicities associated with docetaxel, five SNPs in three genes were identified: UGT1A1 (2 SNPs, p=0.0009 to 0.0094), UGT1A9 (2 SNPs, p=0.0016 to 0.0096), and CYP2A7 (p=0.0027). SNPs in CYP2B6 (p=0.0033), ABCC1 (p=0.0036), and ABCC6 (p=0.0075) were associated with toxicities from thalidomide. Conclusion: We identified nine genes in which SNPs were potentially significantly associated with clinical response and toxicity to treatment. These results highlight the important role that non-CYP450 and phase II drug metabolizing enzymes may play in the efficacy and disposition of docetaxel and thalidomide. Confirmatory studies are warranted.

No significant financial relationships to disclose.

Pharmacogenetics of organic anion transporting peptides (OATP): An association of a SLCO1B3 polymorphism with the overall survival in white Caucasian patients with androgen independent prostate cancer

5118

Background: Steroid hormone have been implicated in playing a fundamental role in pathogenesis of prostate cancer and several studies have reported an association between clinical outcome and polymorphism of genes involved in steroid metabolism. Recently we observed that polymorphic enzyme CYP17 which influences the rate-limiting steps in androgen biosynthesis was associated with overall survival. However, the effect of genetic variation on the transport of steroid hormones remains unknown. The purpose of this study was to evaluate the association between clinical outcomes in patients with androgen independent prostate cancer, and polymorphism in the SLCO1B3 gene that are potentially important in the differential uptake of steroid hormones. Methods: One hundred seventy nine white Caucasian patients with androgen independent prostate cancer were enrolled in this study. The duration of survival was computed from the date of prostate cancer diagnosis until the date of death or last follow-up. The SLCO1B3 polymorphism (-334 T>G) was analyzed using an automated sequencer. Results: The T allele (TT or TG) and G allele (GG) frequency of SLCO1B3 among all patients was 0.16 and 0.84, respectively. The frequency of the SLCO1B3 genotype was similar in patients and healthy volunteer. No significant differences were observed in the frequencies of the SLCO1B3 genotype in relation to categorized Gleason scores and age at diagnosis. Interestingly, the median survival was significantly longer in 134 patients with the SLCO1B3 G allele (8.4 years) genotype than 45 patients carrying at least one T allele (6.4 years) genotype (hazard ratio=1.58, 95%CI: 1.13 - 2.26, p=0.0105 by Logrank test). Similarly, the survival probability at ten years (22.9% in T allele vs 41.1% in G allele) is observed. Conclusions: Our results indicate that the SLCO1B3 polymorphism is associated with overall survival in white Caucasian patients with androgen independent prostate cancer. Large population-based studies are needed to confirm these results.

No significant financial relationships to disclose.

Variants in the SLCO1B3 Gene: Interethnic Distribution and Association with Paclitaxel Pharmacokinetics

To explore retrospectively the relationships between paclitaxel pharmacokinetics and three known, non-synonymous single-nucleotide polymorphisms (SNPs) in SLCO1B3, the gene encoding organic anion transporting polypeptide (OATP)1B3. Accumulation of [(3)H]paclitaxel was studied in Xenopus laevis oocytes injected with cRNA of Oatp1b2, OATP1A2, OATP1B1, OATP1B3, OAT1, OAT3, OCT1, and NTCP. The 334T>G (Ser112Ala), 699G>A (Met233Ile), and 1564G>T (Gly522Cys) loci of SLCO1B3 were screened in 475 individuals from five ethnic groups and 90 European Caucasian cancer patients treated with paclitaxel. Only OATP1B3 was capable of transporting paclitaxel to a significant extent (P=0.003). The 334T>G and 699G>A SNPs were less common in the African-American and Ghanaian populations (P<0.000001). Paclitaxel pharmacokinetics were not associated with the studied SNPs or haplotypes (P>0.3). The studied SNPs in SLCO1B3 appear to play a limited role in the disposition of paclitaxel, although their clinical significance in other ethnic populations remains to be investigated.

Bony metastatic disease responses to sorafenib (BAY 43–9006) independent of PSA in patients with metastatic androgen independent prostate cancer

4506

Background: Sorafenib is a novel bis-aryl urea, multi-kinase inhibitor, approved for the treatment of advanced renal cell carcinoma. It inhibits b- and c-Raf kinase, PDGFR, c-kit, VEGFR, Flt-3 and p38 and demonstrates anti-proliferative and anti-angiogenic activity. Studies have shown a role for anti-angiogenic therapy for androgen-independent prostate cancer (AIPC). Evidence suggests that the Ras-Raf-MAPK-ERK signaling pathway is dysregulated in AIPC and might be targeted by sorafenib. Methods: 22 patients (pts) with progressive metastatic AIPC enrolled in an open-label, single arm phase II study. The primary objective was to determine if sorafenib is associated with a 50% 4 month probability of progression free survival as determined by clinical, radiographic, and PSA criteria. Sorafenib was given continuously at a dose of 400 mg orally twice daily in 28-day cycles. Clinical assessment and PSA measurement occurred every cycle with radiographic measurements every 2 cycles. Results: Baseline patient characteristics included a median (range) age of 64 (51–78), Gleason 8 (6–9), PSA 226.4 ug/l (2–1905), Alk Phos 108 u/l (48–259), Hb 12.7 g/dl (10.2–15.1). 60% of patients had received one prior chemotherapy regimen. Of the 19 pts with progressive disease, 10 progressed only by PSA criteria in the absence of evidence of clinical and radiographic progression. Two pts were found to have dramatic disappearance of bone metastatic lesions as demonstrated by bone scan, even though they met PSA progression criteria at the time the scans were obtained. Toxicities likely related to treatment include: one grade 3 hypertension and hand-foot syndrome; grade 1/2 toxicities: fatigue, anorexia, hypertension, skin rash, nausea, and diarrhea. Conclusion: Sorafenib in AIPC is relatively well tolerated with 2 patients demonstrating evidence of improved bony metastatic lesions. Interpretation of this study is complicated by discordant radiographic and PSA responses. PSA may not be an adequate biomarker for monitoring sorafenib activity. Further study of sorafenib in metastatic AIPC using clinical and radiographic endpoints is warranted.

No significant financial relationships to disclose.

Interim analysis of phase I trial of 17-DMAG

13148

Background: 17-Dimethylaminoethylamino-17-Demethoxygeldanamycin (17-DMAG) binds specifically to heat-shock protein 90, leading to degradation of oncogene client proteins, inhibiting tumor growth. Based on in vitro/in vivo data, 17-DMAG has potent antitumor activity. Methods: 17-DMAG was administered by 1–2 hour infusion twice weekly for 4 weeks/cycle. Eligibility criteria included: solid tumor or lymphoma, ECOG ≤ 2 and adequate organ function. Exclusion criteria: brain metastases, pregnancy, prolonged QTc, or uncontrolled illness. Accelerated titration escalation design, one patient/cohort enters until a single patient experiences dose-limiting toxicity (DLT) or two patients exhibit grade ≥ 2 (G2) toxicity (except nausea / vomiting) during the first cycle. The maximum tolerable dose (MTD) is the dose level at which no more than 1/6 patients experience DLT and the dose below that at which at least 2/6 patients have DLT. Primary objectives: to determine the toxicity profile, and MTD of twice weekly 17-DMAG. Secondary endpoints: pharmacokinetics (PK) and pharmacodynamics of 17-DMAG. PK were determined by LC-MS on blood samples collected before and serially up to 48 hours after 17-DMAG infusion. Results: 6 patients (one patient per dose level) with the following diagnoses were accrued and treated: renal cell, pancreatic, medullary thyroid, NSCLC, and two colorectal cancers. The DLT and MTD have not yet been achieved. 17-DMAG toxicities have been acceptable, nausea/vomiting being the most common toxicity observed. Three patients developed G1 nausea, one patient had G3 nausea. Two patients had G2 vomiting. Other G1 toxicities included: diarrhea, weight loss, fatigue, elevated transaminases, hair loss, and leukocytopenia. PK results showed significant intra-patient variability as the dose was increased from 1–12 mg/m2 over 6 dose levels; the mean AUC increased from 370–970 ng*hr/mL, and the mean Cmax increased from 36–79 ng/mL. There was a 5-fold range in clearance (range: 6.5–33.1 L/h), but there was no association between dose and clearance. Following a single dose, the terminal phase half-life ranged from 16.4 - 24.3 hours. Conclusions: Since the DLT and MTD have not been reached, accrual will continue.

No significant financial relationships to disclose.

Phase I study of lenalidomide, a novel thalidomide analog, in patients with refractory metastatic cancer

13038

Background: Lenalidomide (L), CC5013, is a thalidomide (T) analog that has shown activity in multiple myeloma and myelodysplastic syndromes (MDS); including activity in pts refractory to T. Preclinical studies suggest L has more potent immunomodulatory and antiangiogenic activity than T. We have conducted a phase I clinical trial of L to determine the maximum-tolerated dose (MTD), characterize the side-effects, characterize pharmacokinetics (PK) in pts with solid tumors. Methods: Pts with refractory metastatic cancer were treated on a modified Fibonacci dose-escalation scheme with an oral daily dose of L. Therapy was continued until MTD or disease progression. Results: Forty-five pts have been enrolled (M/F: 37/8). Median age 68 yrs (range, 25–89 yrs). Tumor types include prostate cancer (36 pts), adrenal carcinoma (3 pt), renal cell carcinoma (1 pt), choleangiocarcinoma (1 pt), small intestine cancer (1 pt), colon cancer (2 pt), and melanoma (1 pt). Dose levels were: 5 mg (n = 3), 10 mg (n = 6), 15 mg (n = 3), 20 mg (n = 3 + 7), 25 mg (n = 6), 30 mg (n = 8), 35 mg (n = 6) and 40 mg (n = 3). Due to side effects the dosing schedule was modified from daily dosing to daily dosing for 21 out of 28 days. Therapy has been well tolerated with most frequent gr 1 and gr 2 toxicities include nausea (43%), myalgia (38%), pruritis/rash (54%), and fatigue (38%), neutropenia (30%) with gr 3 diarrhea (n = 1), hypotension (n = 1), pulmonary effusions (n = 1), thromboses (n = 2) and gr 4 neutropenia (n = 2), arrhythmias (n = 1), hemolysis (n = 1). Dose escalation continues. There were no differences observed between dose levels for either oral clearance values (p = 0.47) or the apparent volume of distribution (Vz) values (p = 0.23). Dose-normalized AUC(0-∞), dose-normalized peak concentrations (Cmax), or half-life (t1/2) did not vary between dose levels (p > 0.12). Conclusion: L has been well tolerated up to 35 mg/d (21 days on; 7 days off), doses higher than the recently FDA-approved doses of 5 and 10 mg/d. In this dose range L exhibits linear PK. Tolerability to myelosuppression the dose-limiting toxicity in pts with MDS may therefore be improved in pts without hematological malignancies.

No significant financial relationships to disclose.

A phase II trial of docetaxel, thalidomide, bevacizumab, and prednisone in patients (pts) with metastatic androgen-independent prostate cancer (AIPC)

13037

Background: Angiogenesis plays a vital role in progression of prostate cancer. Antiangiogenic agents’ thalidomide (Td) and bevacizumab (Bv) have been shown in Phase II trials to enhance docetaxel (Doc) activity in metastatic AIPC. Td plus Doc also improved median overall survival as compared to Doc alone. Td and Bv have different antiangiogenic mechanisms. Td appears to affect bFGF, alter circulating endothelial cells and inhibit TNF expression; yet Td does not affect the target of Bv (VEGF). Since tumor angiogenesis is a complex interplay of multiple angiogenic factors, we reasoned that combination of mechanistically different antiangiogenic agents Td and Bv with Doc might be associated with an adequately high and durable PSA response to merit further study. Methods: Pts have progressive, metastatic AIPC, with no prior chemotherapy for AIPC, or prior Td or Bv. Treatment consists of Doc 75 mg/m2 plus Bv 15 mg/kg day 1, q 21 days as a cycle (C), plus Td 200 mg qhs and prednisone10 mg qd. Enoxaparin 1 mg/kg/d sq is used for thrombosis prevention. PSA is assayed q C and radiographic studies are performed at C 0, C 2, & then q 3 Cs. Results: To date, 22 of planned 60 pts have been enrolled, median age 65 [54–79], Gleason score 8 [Gs 6∼7: 32%, Gs 8∼10: 68%], on-study PSA 111 ng/ml [7.7–4399], & pre-treatment PSA doubling time 1.7 months [0.8–18.2]. I) All 22 pts are actively on trial without progression, with median treatment 6 Cs [1–12]. II) 20 pts treated ≥ 2 Cs, 17 (85%) had PSA declines of >50%, 2 declines of >20%, and 1 stable; median duration of >50% PSA decline is 5 Cs [0∼11]. III) 14 pts (of the 20) treated ≥ 5 Cs, 13 (93%) had >50% PSA declines; 6 of them also had measurable disease: 1 CR, 2 PR, & 3 SD (50% RR). IV) Significant toxicities include grade 4 neutropenia (11/22), grade 3 febrile neutropenia (3/22), syncope (2/22), & colon perforation (1/22). No thrombosis was seen. Conclusions: This trial tests a novel strategy of improving conventional treatment of metastatic AIPC. Our data show that the combination of two mechanistically different antiangiogenic agents Td and Bv with Doc does result in a high durable response in PSA (85∼93%) with acceptable toxicities, suggesting that further studies with the combination are warranted. Accrual is continuing.

No significant financial relationships to disclose.