Phase IIIb randomized study of lenalidomide plus rituximab (R2) followed by maintenance in relapsed/refractory NHL: Analysis of patients with double-refractory or early relapsed follicular lymphoma (FL)

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Background: Chemoresistant patients with FL and those who progress within 2 y after initial diagnosis have poor outcomes (Casulo. JCO. 2015) and highlight an unmet need. Methods: MAGNIFY (NCT01996865) is a phase IIIb, multicenter, open-label study of relapsed/refractory (R/R) NHL patients, including grades 1-3b or transformed FL (tFL). Patients receive 12 cycles of lenalidomide plus rituximab (R2); those with stable disease or better are randomized 1:1 to maintenance R2 or rituximab alone. The primary endpoint is progression-free survival (PFS). This analysis focuses on FL: double-refractory (DR) patients are refractory to both rituximab (as monotherapy or combination) and an alkylating agent, and early relapse (ER) patients progressed or relapsed within 2 y of initial diagnosis. Results: As of July 19, 2016, the R/R FL population (N = 117) included 32 (27%) DR and 43 (37%) ER patients, median ages of 64 and 65 y, respectively, mostly grade 1-3a FL (94%; 91%) and 2 tFL (1 DR; 1 ER); 72% and 49% were stage IV at study entry. Patients had a median of 2 prior regimens (DR 3; ER 2). Of ER patients, 31 had first-line R-chemo vs 12 with R-mono/other. Response rates are in Table 1. Median time to response was 2.8 mo for DR and 2.7 mo for ER patients, with median duration not reached. 1-y PFS for FL patients was 66% (DR 66%; ER 45%); 1-y PFS for ER patients with first-line R-chemo was 50% vs 27% in others. Common grade ≥3 treatment-emergent AEs for DR and ER patients were neutropenia (53%; 33%), leukopenia (9%; 12%), and lymphopenia (9%; 5%). Conclusions: R2 followed by maintenance showed favorable activity and tolerable safety profiles in FL patients who are double-refractory or had early relapse ( < 2 years) after initial diagnosis. Enrollment in MAGNIFY is ongoing. Clinical trial information: NCT01996865. [Table: see text]

Abstract P5-08-15: Real-world treatment patterns and survival among triple negative breast cancer patients versus patients with other breast cancer subtypes in early stage breast cancer

Background: It is generally accepted that outcomes of breast cancer (BC) patients (pts) differ by tumor characteristics, but relatively few studies have examined treatment patterns and outcomes in early stage disease by hormone receptor (HR) and HER2 status.

Methods: This retrospective study used physician-reported clinical information (date and stage at diagnosis, HER2 and HR status) for commercially insured BC pts from the Optum Oncology Management Registry linked with the Optum Research Database (medical and pharmacy claims from a national US health plan) and death data from Social Security Administration files from 01/2008 to 6/2014. Pts diagnosed with early stage breast cancer (ESBC) were examined. The index date was diagnosis of BC. Adult pts (≥18 yrs old) had to have known HR and HER2 status, continuous enrollment in the health plan from initial diagnosis for ≥6 months, surgery and systemic cancer therapy. Neo-adjuvant and adjuvant therapy (initial phase of care) based on timing of claims for NCCN-recommended therapy were examined, as well as survival and development of metastasis (based on claims with ICD-9 codes 196.0x, 196.2x, 196.5x-199.0x) after initial phase of care during the study period. Differences across the HR/HER2 subtypes were examined using t-test for continuous variables and chi-square test for categorical variables.

Results: Among 6,881 ESBC pts identified, 15% (n=1038) were TNBC pts, 65% HR+/HER2-, 14% HR+/HER2+ and 6% HR-/HER2+. Mean (median) age was 52 (53) years. Treatment patterns and outcomes vary by tumor subtype (Table).

 HR-/HER2-HR+/HER2-HR-/HER2+HR+/HER2+ N=1038N=4452N=401N=990Length of follow-up, mths, mean(SD)*, median27 (16), 2328 (16), 2529 (16), 2527 (15), 24Length of initial phase of care – mths, mean(SD)*, media10 (7), 922 (15), 1915 (9), 1423 (14), 19Pts with systemic neo-adjuvant therapy N (%)*303 (29)531 (12)140 (35)216 (22)Most common neo-adjuvant regimens (%)Paclitaxel, cyclophosphamide, doxorubicin (45%)Paclitaxel, cyclophosphamide, doxorubicin (31%)Docetaxel, carboplatin, trastuzumab (44%)Docetaxel, carboplatin, trastuzumab (31%)Pts with systemic adjuvant therapy N (%)*740 (71)4065 (91)366 (91)935 (94)Most common adjuvant regimens (%)Paclitaxel, cyclophosphamide, doxorubicin (30%)Tamoxifen (19%)Docetaxel, carboplatin, trastuzumab (30%)Docetaxel, carboplatin, trastuzumab, tamoxifen (9%)Evidence of distant metastasis N (%)*78 (7.5)76 (1.7)17 (4.2)15 (1.5)Mortality N (%)*23(2.2)23 (0.5)1 (0.3)3 (0.3)*p&lt;0.05

Conclusions: The most common neo-adjuvant and adjuvant chemotherapy agents received were similar across HER2 subtypes and regimens for HR+ and HER2+ patients also included hormonal or HER2 targeted agents. TNBC pts had the shortest length of initial phase of care (mean 10 mths), though this cohort had the second highest percentage of patients receiving systemic neo-adjuvant therapy. Development of distant metastasis and mortality during the study period were highest for the HR-/HER2- patients, at 7.5% and 2.2% respectively. Development of novel targets and therapies for TNBC may significantly benefit patients with this BC subtype, in both neo-adjuvant and adjuvant setting to improve outcomes.

Citation Format: DaCosta Byfield S, Abushamaa AM, Becker LK, Shepherd SP, Ricker JL, Bonnet P. Real-world treatment patterns and survival among triple negative breast cancer patients versus patients with other breast cancer subtypes in early stage breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-08-15.

Efficacy and Biological Correlates of Response in a Phase II Study of Venetoclax Monotherapy in Patients with Acute Myelogenous Leukemia

We present a phase II, single-arm study evaluating 800 mg daily venetoclax, a highly selective, oral small-molecule B-cell leukemia/lymphoma-2 (BCL2) inhibitor in patients with high-risk relapsed/refractory acute myelogenous leukemia (AML) or unfit for intensive chemotherapy. Responses were evaluated following revised International Working Group (IWG) criteria. The overall response rate was 19%; an additional 19% of patients demonstrated antileukemic activity not meeting IWG criteria (partial bone marrow response and incomplete hematologic recovery). Twelve (38%) patients had isocitrate dehydrogenase 1/2 mutations, of whom 4 (33%) achieved complete response or complete response with incomplete blood count recovery. Six (19%) patients had BCL2-sensitive protein index at screening, which correlated with time on study. BH3 profiling was consistent with on-target BCL2 inhibition and identified potential resistance mechanisms. Common adverse events included nausea, diarrhea and vomiting (all grades), and febrile neutropenia and hypokalemia (grade 3/4). Venetoclax demonstrated activity and acceptable tolerability in patients with AML and adverse features.

SIGNIFICANCE

Venetoclax monotherapy demonstrated clinical activity in patients with AML (relapsed/refractory or unfit for intensive chemotherapy) with a tolerable safety profile in this phase II study. Predictive markers of response consistent with BCL2 dependence were identified. Clinical and preclinical findings provide a compelling rationale to evaluate venetoclax combined with other agents in AML. Cancer Discov; 6(10); 1106-17. ©2016 AACRSee related commentary by Pullarkat and Newman, p. 1082This article is highlighted in the In This Issue feature, p. 1069.

Phase 1 dose escalation trial of ilorasertib, a dual Aurora/VEGF receptor kinase inhibitor, in patients with hematologic malignancies

BACKGROUND

Ilorasertib (ABT-348) is a novel inhibitor of Aurora kinase, vascular endothelial growth factor (VEGF) and platelet-derived growth factor receptors, and the Src families of tyrosine kinases. Ilorasertib alone or in combination with azacitidine demonstrated activity in preclinical models in various hematological malignancies, indicating that pan-Aurora kinase and multiple kinase inhibition may have preferential antileukemic activity. This phase 1 trial determined the safety, pharmacokinetics, and preliminary antitumor activity of ilorasertib alone or combined with azacitidine in advanced hematologic malignancies.

PATIENTS AND METHODS

Fifty-two patients (median age, 67 years; 35 % with >4 prior regimens) with acute myelogenous leukaemia (AML; n = 38), myelodysplastic syndrome (n = 12), or chronic myelomonocytic leukaemia (n = 2) received 3 or 6 doses of ilorasertib per 28-day cycle and were assigned to arm A (once-weekly oral), B (twice-weekly oral), C (once-weekly oral plus azacitidine), or D (once-weekly intravenous) treatment.

RESULTS

Maximum tolerated doses were not determined; the recommended phase 2 oral monotherapy doses were 540 mg once weekly and 480 mg twice weekly. The most common grade 3/4 adverse events were hypertension (28.8 %), hypokalemia (15.4 %), anemia (13.5 %), and hypophosphatemia (11.5 %). Oral ilorasertib pharmacokinetics appeared dose proportional, with a 15-hour half-life and no interaction with azacitidine. Ilorasertib inhibited biomarkers for Aurora kinase and VEGF receptors, and demonstrated clinical responses in 3 AML patients.

CONCLUSIONS

Ilorasertib exhibited acceptable safety and pharmacokinetics at or below the recommended phase 2 dose, displayed evidence of dual Aurora kinase and VEGF receptor kinase inhibition, and activity in AML.

Randomized phase II study of carboplatin and paclitaxel with either linifanib or placebo for advanced nonsquamous non-small-cell lung cancer

PURPOSE

Linifanib, a potent, selective inhibitor of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) receptors, has single-agent activity in non-small-cell lung cancer (NSCLC). We evaluated linifanib with carboplatin and paclitaxel as first-line therapy of advanced nonsquamous NSCLC.

PATIENTS AND METHODS

Patients with stage IIIB/IV nonsquamous NSCLC were randomly assigned to 3-week cycles of carboplatin (area under the curve 6) and paclitaxel (200 mg/m(2)) with daily placebo (arm A), linifanib 7.5 mg (arm B), or linifanib 12.5 mg (arm C). The primary end point was progression-free survival (PFS); secondary efficacy end points included overall survival (OS) and objective response rate.

RESULTS

One hundred thirty-eight patients were randomly assigned (median age, 61 years; 57% men; 84% smokers). Median PFS times were 5.4 months (95% CI, 4.2 to 5.7 months) in arm A (n = 47), 8.3 months (95% CI, 4.2 to 10.8 months) in arm B (n = 44), and 7.3 months (95% CI, 4.6 to 10.8 months) in arm C (n = 47). Hazard ratios (HRs) for PFS were 0.51 for arm B versus A (P = .022) and 0.64 for arm C versus A (P = .118). Median OS times were 11.3, 11.4, and 13.0 months in arms A, B, and C, respectively. HRs for OS were 1.08 for arm B versus A (P = .779) and 0.88 for arm C versus A (P = .650). Both linifanib doses were associated with increased toxicity, including a higher incidence of adverse events known to be associated with VEGF/PDGF inhibition. Baseline plasma carcinoembryonic antigen/cytokeratin 19 fragments biomarker signature was associated with PFS improvement and a trend toward OS improvement with linifanib 12.5 mg.

CONCLUSION

Addition of linifanib to chemotherapy significantly improved PFS (arm B), with a modest trend for survival benefit (arm C) and increased toxicity reflective of known VEGF/PDGF inhibitory effects.

Linifanib versus Sorafenib in patients with advanced hepatocellular carcinoma: results of a randomized phase III trial

PURPOSE

This open-label phase III trial evaluated efficacy and tolerability of linifanib versus sorafenib in patients with advanced hepatocellular carcinoma (HCC) without prior systemic therapy.

PATIENTS AND METHODS

Patients were randomly assigned in a 1:1 ratio to linifanib 17.5 mg once daily or sorafenib 400 mg twice daily. Patients were stratified by region (Outside Asia, Japan, and rest of Asia), Eastern Cooperative Oncology Group performance score (ECOG PS; 0 or 1), vascular invasion or extrahepatic spread (yes or no), and hepatitis B virus (HBV) infection (yes or no). The primary end point of the study was overall survival (OS). Secondary end points were time to progression (TTP) and objective response rate (ORR) per RECIST v1.1.

RESULTS

We randomly assigned 1,035 patients (median age, 60 years; Asian, 66.6%; ECOG PS 0, 65.2%; HBV, 49.1%; vascular invasion or extrahepatic spread, 70.1%). Median OS was 9.1 months on the linifanib arm (95% CI, 8.1 to 10.2) and 9.8 months on the sorafenib arm (95% CI, 8.3 to 11.0; hazard ratio [HR], 1.046; 95% CI, 0.896 to 1.221). For prespecified stratification subgroups, OS HRs ranged from 0.793 to 1.119 and the 95% CI contained 1.0. Median TTP was 5.4 months on the linifanib arm (95% CI, 4.2 to 5.6) and 4.0 months on the sorafenib arm (95% CI, 2.8 to 4.2; HR, 0.759; 95% CI, 0.643 to 0.895; P = .001). Best response rate was 13.0% on the linifanib arm versus 6.9% on the sorafenib arm. Grade 3/4 adverse events (AEs); serious AEs; and AEs leading to discontinuation, dose interruption, and reduction were more frequent with linifanib (all P < .001).

CONCLUSION

Linifanib and sorafenib had similar OS in advanced HCC. Predefined superiority and noninferiority OS boundaries were not met for linifanib and the study failed to meet the primary end point. TTP and ORR favored linifanib; safety results favored sorafenib.

Randomized phase II open-label study of mFOLFOX6 in combination with linifanib or bevacizumab for metastatic colorectal cancer

BACKGROUND

Although CRC is the third most commonly diagnosed cancer in the United States, second-line CRC treatment is limited. In this trial we examined the efficacy and safety of linifanib, an oral, potent, selective tyrosine kinase inhibitor of vascular endothelial growth factor and platelet-derived growth factor receptor families, with mFOLFOX6, compared with bevacizumab and mFOLFOX6, in previously treated metastatic CRC.

PATIENTS AND METHODS

One hundred forty-eight patients with advanced CRC previously treated with fluoropyrimidine or irinotecan received bevacizumab (10 mg/kg, intravenous), low-dose linifanib (7.5 mg), or high-dose linifanib (12.5 mg), with mFOLFOX6. The primary end point was progression-free survival (PFS). Secondary objectives included overall survival (OS), objective response rate (ORR), and safety.

RESULTS

No statistically significant differences in PFS occurred between bevacizumab and linifanib doses (low, hazard ratio [HR], 1.453 [95% confidence interval [CI], 0.830-2.539]; high, HR, 1.257 [95% CI, 0.672-2.351]). Median OS values were similar for bevacizumab and high-dose linifanib (bevacizumab, 16.5 months [95% CI, 13.0-not available]; high-dose linifanib, 16.4 months [95% CI, 11.9-21.7]; low-dose linifanib, 12.0 months [95% CI, 10.1-13.0]). ORRs were similar (bevacizumab, 34.7% [95% CI, 21.7-49.6]; low-dose linifanib, 24.0% [95% CI, 13.1-38.2]; high-dose linifanib, 22.4% [95% CI, 11.8-36.6]). Median cycles of 5-fluorouracil were reduced in the linifanib arms, versus the bevacizumab arm. Grade 3/4 adverse event occurrences were more frequent with linifanib. Palmar-plantar erythrodysesthesia, hypothyroidism, and thrombocytopenia were more common with high-dose linifanib than bevacizumab.

CONCLUSION

Combining linifanib with mFOLFOX6 as a second-line treatment for metastatic CRC did not improve PFS, radiographic findings, or duration of response versus bevacizumab and mFOLFOX6.

Results of a phase I, open-label, randomized, crossover study evaluating the effects of linifanib on QTc intervals in patients with solid tumors

PURPOSE

Linifanib is a selective inhibitor of the vascular endothelial growth factor and platelet-derived growth factor family of tyrosine kinase inhibitors. The purpose of this high-precision QT study was to evaluate the effects of linifanib on cardiac repolarization in patients with advanced metastatic tumors.

METHODS

Enrolled patients (n = 24) had measurable disease refractory to standard therapies, ECOG performance status of 0-1, and adequate organ function. Patients were randomized in a 2-sequence, 2-period crossover design. Serial ECG measurements and pharmacokinetic samples were collected for each crossover period. An intersection-union test was performed for time-matched baseline-adjusted QTcF intervals. An exposure-response analysis was explored to correlate the plasma concentration and QTcF.

RESULTS

The maximum 95 % upper confidence bound for the baseline-adjusted QTcF was 4.3 ms at hour 3 at the maximum tolerated linifanib dose of 0.25 mg/kg. Linifanib did not meet the regulatory threshold (10 ms) for QT prolongation. Exposure-response modeling showed that the QTcF change was not significant at the maximum plasma concentration.

CONCLUSIONS

Linifanib does not significantly affect cardiac repolarization in patients with advanced solid tumors.

Exposure-response (safety) analysis to identify linifanib dose for a Phase III study in patients with hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related deaths and the fifth most common cancer globally. Hepatocellular carcinoma produces highly vascular tumors that overexpress vascular endothelial growth factor (VEGF), thus making VEGF a promising therapeutic target. The competitive inhibitor linifanib (ABT-869) has selectivity for VEGF and platelet-derived growth factor (PDGF) receptors and minimal activity against unrelated tyrosine and serine and threonine kinases. However, the optimal dosing regimen for linifanib in HCC patients is not yet known.

OBJECTIVE

This study attempts to identify a linifanib dose or dosing regimen with an acceptable safety profile for a Phase III study in HCC patients.

METHODS

The pharmacokinetic (PK) properties of linifanib were characterized from 2 Phase I and 3 Phase II clinical trials. Of the 266 patients evaluated, the median weight was 68 kg (range, 35-177 kg), 64% were male, and 87.6% of patients received an oral solution of linifanib, whereas 12.4% received a tablet formulation. Approximately 95% of patients received drug based on weight, with the remaining on a fixed-dosing regimen. A population PK analysis was conducted to characterize the linifanib exposure for each patient. Linifanib Cmax and AUC derived from the population PK properties were correlated with the rates of adverse events (AEs).

RESULTS

Linifanib PK properties are dose proportional for the 0.10-mg/kg to 0.25-mg/kg once daily dose range and are time independent after repeated oral dosing. The Tmax of linifanib is approximately 3 hours, and the t½ is approximately 1 day. The most common AEs related to linifanib PK were hypertension (P = 0.02 for Cmax and P = 0.01 for AUC), diarrhea (P = 0.001 for Cmax and P = 0.0012 for AUC), proteinuria (P = 0.001 for Cmax and P = 0.002 for AUC), and asthenia (P = 0.03 for AUC). Weight and sex were identified as covariates for Cmax, and sex was identified as a covariate for AUC. The predicted AE range for females was slightly higher compared with males; however, the AE range is tighter for the weight range for fixed dosing compared with weight-based dosing, regardless of sex.

CONCLUSIONS

The PK properties of linifanib support a one-compartment model with first-order absorption and elimination. Comparison of weight-based and fixed dosing revealed predicted AE rates to be similar, with a tighter AE range for fixed dosing. The safety profile of linifanib, therefore, supports a 17.5 mg fixed starting dose for Phase III clinical studies.

Phase III trial of linifanib versus sorafenib in patients with advanced hepatocellular carcinoma (HCC)

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Background: Linifanib (ABT-869; Lin) is a potent and selective inhibitor of the vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) receptor tyrosine kinase families. In a phase II trial in patients (pts) with advanced HCC, Lin showed clinical activity (objective response rate [ORR] 10.5% in Child-Pugh A [CPA] pts). This open-label, global phase 3 trial evaluated Lin versus sorafenib (Sor) as first-line therapy in pts with advanced CPA HCC (NCT01009593). Methods: Pts were randomized 1:1 to Lin 17.5 mg QD or Sor 400 mg BID and stratified by region (non-Asia/Japan/rest of Asia), ECOG performance status (0/1), vascular invasion or extrahepatic spread (yes/no) and HBV infection (yes/no). The primary efficacy endpoint was overall survival (OS); both non-inferiority (margin 1.0491) and superiority hypotheses were to be tested. Secondary efficacy endpoints included time to progression (TTP) and ORR, using RECIST v1.1. AE severity was graded using NCI-CTCAE v4.0. Results: 1035 pts (median age 60 y, 68% Asian, 65% ECOG 0, 49% HBV, 70% vascular invasion or extrahepatic spread) were randomized at 149 sites in 26 countries. Hazard ratio (HR) for OS was 1.046 (95% CI: 0.896, 1.221). Median OS (95% CI) was 9.1 months (m) (8.1, 10.2) on Lin and 9.8 m (8.3, 11.0) on Sor. For all pre-specifed subgroup analyses, OS HRs ranged from 0.793-1.119, and the 95% CI contained 1.0. TTP HR was 0.759 (95% CI: 0.643, 0.895; p=0.001) favoring Lin. Median TTP (95% CI) was 5.4 m (4.2, 5.6) on Lin and 4.0 m (2.8. 4.2) on Sor. ORR was 13.0% on Lin and 6.9% on Sor. Grade 3/4 AEs, serious AEs and AEs leading to discontinuations, dose interruptions and reductions were more frequent on Lin versus Sor (all p<0.001). Conclusions: Lin and Sor resulted in similar OS in advanced HCC. Predefined superiority and non-inferiority OS boundaries were not met for Lin. Secondary endpoints (TTP and ORR) favored Lin while safety results favored Sor. Clinical trial information: NCT01009593.

Phase 2 trial of linifanib (ABT-869) in patients with unresectable or metastatic hepatocellular carcinoma

BACKGROUND

The efficacy and safety of linifanib (ABT-869), a selective inhibitor of vascular endothelial growth factor and platelet-derived growth factor receptor tyrosine kinases, were assessed in this phase 2, single-arm, open-label, multicenter trial.

METHODS

Eligible patients had unresectable or metastatic hepatocellular carcinoma and had received ≤ 1 prior systemic therapy. Patients received oral linifanib at a fasting dose of 0.25 mg/kg,. The primary endpoint was the progression-free rate at 16 weeks. Tumor response was assessed every 8 weeks. Secondary endpoints included the time to disease progression, overall survival, and objective response rate. Safety was also assessed.

RESULTS

Of the 44 patients enrolled, the majority were Asian (89%), had received no prior systemic therapy (82%), had Child-Pugh class A hepatic function (86%), and had hepatitis B virus infection (61%). The estimated progression-free rate at 16 weeks was 31.8% (34.2% for patients with Child-Pugh class A hepatic function), the estimated objective response rate was 9.1% (10.5% for patients with Child-Pugh class A hepatic function), the median time to disease progression was 3.7 months (3.7 months for patients with Child-Pugh class A hepatic function), and the median overall survival was 9.7 months (10.4 months for patients with Child-Pugh class A hepatic function). The most common linifanib-related adverse events were diarrhea (55%) and fatigue (52%). The most common linifanib-related grade 3/4 adverse events were hypertension (25%) and fatigue (14%). Serum levels of biomarkers cancer antigen (CA) 125, cytokeratin fragment (CYFRA)21.1, and protein induced by vitamin K absence or antagonist II (PIVKA) demonstrated potential as prognostic indicators of patient response or outcome.

CONCLUSIONS

Single-agent linifanib was found to be clinically active in patients with advanced hepatocellular carcinoma, with an acceptable safety profile.

Randomized phase II open-label study of mFOLFOX6 in combination with linifanib or bevacizumab for metastatic colorectal cancer

3532

Background: Linifanib is a potent and selective inhibitor of VEGF/PDGF receptors. This trial assessed the efficacy and safety of mFOLFOX6 in combination with linifanib or bevacizumab as second-line treatment for metastatic colorectal cancer (mCRC). Methods: Patients (pts) with measurable mCRC refractory to 1 prior regimen and ECOG PS 0–1, stratified by prior bevacizumab treatment and radiotherapy, were randomized to receive mFOLFOX6 with bevacizumab 10 mg/kg on day (d) 1 of 14-d cycle (Arm A), mFOLFOX6 with daily linifanib 7.5 mg (Arm B), or mFOLFOX6 with daily linifanib 12.5 mg (Arm C). The primary endpoint was progression-free survival (PFS). Severity of adverse events (AEs) was graded using NCI-CTCAE v3.0. Results: 148 pts were randomized at 45 sites in 14 countries. 32 pts (21.6%) had received prior bevacizumab. PFS and response data are shown below (Table). Median survival (OS) was not reached at median follow up 7.6 months. Palmar-plantar erythrodysesthesia (PPE) was the only Grade 3/4 AE significantly higher on linifanib (high dose, 16.3%) vs. bevacizumab (0%). Rate of any Grade 3+ AE was significantly higher on linifanib vs. bevacizumab.Hypertension rates were 41.7% (Arm A), 40.0% (Arm B), and 36.7% (Arm C). AEs dose-related to linifanib were constipation, proctalgia, stomatitis, fatigue, weight decrease, decreased appetite, and PPE. Conclusions: The addition of linifanib to mFOLFOX6, compared to mFOLFOX6 + bevacizumab, did not provide a PFS advantage for mCRC. OS results will be updated for conference presentation. [Table: see text]

Randomized phase II study of carboplatin and paclitaxel with either linifanib or placebo for advanced nonsquamous NSCLC

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Background: Linifanib is a potent and selective inhibitor of VEGF and PDGF receptors with modest single-agent activity in NSCLC. We evaluated the combination of linifanib with carboplatin (C) and paclitaxel (P) for first-line therapy of advanced non-squamous NSCLC. Methods: Patients (pts) with stage IIIB/IV, non-squamous NSCLC, stratified by ECOG PS and gender, were randomized to receive up to six 3-wk cycles of C (AUC 6 mg/ml/min) and P (200 mg/m2) with daily placebo (Arm A), linifanib 7.5 mg (Arm B), or linifanib 12.5 mg (Arm C). The primary endpoint was progression-free survival (PFS); secondary endpoints included overall survival (OS), 12 m survival rate, and objective response rate (ORR). Safety was assessed by NCI-CTCAE v3.0. Results: 138 pts were randomized at 37 sites in 6 countries. Baseline characteristics were: median age, 61 y; men, 57%; smoker, 84%. Efficacy results are shown in the table. Thrombocytopenia was the only Grade 3/4 AE significantly higher on linifanib (Arm B: 16.7%; Arm C: 29.8%) vs. placebo (2.1%). Other adverse events (AEs) related to the dose of linifanib were diarrhea, thrombocytopenia, hypertension, weight loss, palmar-plantar erythrodysaesthesia syndrome, and hypothyroidism. Analysis of samples for predictive biomarkers including serum VEGF and placental growth factor are underway. Conclusions: The addition of linifanib to chemotherapy was tolerable at the doses tested and resulted in a significant improvement in PFS, with a modest survival improvement for Arm C in first-line therapy of advanced non-squamous NSCLC. [Table: see text]

Association of baseline plasma biomarker signature with survival in advanced NSCLC patients on linifanib

e13583

Background: Linifanib is a potent and selective VEGF and PDGF receptor inhibitor that has activity in unselected, advanced NSCLC patients (pts) both as monotherapy in the relapsed setting and with carboplatin (C) and paclitaxel (P) in the first-line setting. A baseline plasma biomarker signature identifying NSCLC pts most sensitive to linifanib is needed. Methods: An exploratory retrospective analysis of four randomized clinical trials including linifanib or other treatments in relapsed NSCLC was conducted. Evaluable baseline plasma samples were obtained from 116 pts who received linifanib and 71 pts on other treatments. A signature combining established tumor markers (carcinoembryonic antigen [CEA] and fragments of cytokeratin 19 [CYFRA 21-1]) was derived using a sequential BATTing approach. The signature was then tested across a randomized trial of CP + placebo, linifanib 7.5 mg, or linifanib 12.5 mg in first-line advanced, non-squamous NSCLC. Results: In 2/3L NSCLC, the signature was associated with improvement in survival on linifanib monotherapy (HR=0.51 vs. signature negative; P=0.0017), but no improvement in survival on other treatments (P=0.87). In the first-line setting with CP, the signature was associated with significant PFS improvement with linifanib and a trend towards significant overall survival improvement at high dose (Table). Conclusions: A baseline plasma biomarker signature is associated with improved survival in advanced NSCLC patients on linifanib. Incorporation of this signature should be considered in any further investigation of linifanib in NSCLC. [Table: see text]

Phase 2 trial of linifanib (ABT-869) in patients with advanced renal cell cancer after sunitinib failure

PURPOSE

This study assessed the efficacy and safety of linifanib in patients with advanced renal cell carcinoma (RCC) who were previously treated with sunitinib.

MATERIALS AND METHODS

This open-label, multicentre, phase 2 trial of oral linifanib 0.25 mg/kg/day enrolled patients who had prior nephrectomy and adequate organ function. The primary end-point was objective response rate (ORR) per response evaluation criteria in solid tumors (RECIST) by central imaging. Secondary end-points were progression-free survival (PFS), overall survival (OS) and time to progression (TTP). Safety was also assessed.

RESULTS

Fifty-three patients, median age 61 years (range 40-80) were enrolled (August 2007 to October 2008) across 12 North-American centres. Median number of prior therapies was 2 (range 1-4); 43 patients (81%) had clear-cell histology. ORR was 13.2%, median PFS was 5.4 months (95% Confidence Interval (CI): 3.6, 6.0) and TTP was the same; median OS was 14.5 months (95% CI: 10.8, 24.1). The most common treatment-related adverse events (AEs) were diarrhoea (74%), fatigue (74%) and hypertension (66%), and the most common treatment-related Grade 3/4 AE was hypertension (40%).

CONCLUSIONS

Linifanib demonstrated clinically meaningful activity in patients with advanced RCC after sunitinib failure. At 0.25 mg/kg/day, significant dose modifications were required. An alternative, fixed-dosing strategy is being evaluated in other trials.

Potential efficacy of the oral histone deacetylase inhibitor vorinostat in a phase I trial in follicular and mantle cell lymphoma

Vorinostat (suberoylanilide hydroxamic acid, SAHA, Zolinza) is a histone deacetylase inhibitor with clinical activity in cutaneous T-cell lymphoma (CTCL). A phase I trial of oral vorinostat was conducted in Japanese patients with malignant lymphoma. Vorinostat 100 or 200 mg was administered twice daily for 14 consecutive days followed by a 1-week rest interval. Of 10 patients enrolled, four had follicular lymphoma (FL), two mantle cell lymphoma (MCL), two diffuse large B-cell lymphoma, and two CTCL (median age, 60 years; median number of prior regimens, 3). Vorinostat was well tolerated up to 200 mg with only one of six patients developing a dose-limiting toxicity (DLT; Grade 3 anorexia/hypokalemia). Common Grade 3 events were reversible neutropenia (30%), thrombocytopenia, and hypermagnesemia (20% each). The median number of treatment cycles was five (range, 1-36); two patients were continuing treatment. The overall response rate was 40%, with two complete responses/unconfirmed (CRu) and one partial response among FL patients and one CRu among MCL patients. One FL patient maintained CRu for 18.0 months. The median time to achieve CRu among the three patients was 8 months. These data suggest that further investigations of vorinostat in non-Hodgkin lymphoma, focusing on FL and MCL, are warranted.

Differential bortezomib sensitivity in head and neck cancer lines corresponds to proteasome, nuclear factor-kappaB and activator protein-1 related mechanisms

Head and neck squamous cell carcinomas (HNSCC) exhibit constitutive activation of transcription factors nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1), which are modulated by the proteasome and promote resistance to cell death. HNSCC show variable sensitivity to the proteasome inhibitor bortezomib in vitro as well as in murine xenografts and patient tumors in vivo, and the mechanisms are not well understood. To address this question, the sensitivities of nine HNSCC cell lines to bortezomib were determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, and the potential relationship between the sensitivity and bortezomib effects on biological processes was examined in HNSCC lines of differential bortezomib sensitivity. The most sensitive cell line (UM-SCC-11B) underwent cell death at 10(-9) mol/L in vitro and tumor regression at a maximally tolerated dose of bortezomib in a murine xenograft model. The differential sensitivity between UM-SCC-11A and UM-SCC-11B cells corresponded to differences in the extent of suppression of proteasome activity, ubiquitinated protein degradation, and NF-kappaB and AP-1 activation. Lower concentrations of bortezomib transiently increased NF-kappaB and sustained AP-1 activation in UM-SCC-11A cells. AP-1 reporter activity and cell density of UM-SCC-11A were suppressed when bortezomib was combined with c-Jun NH(2)-terminal kinase and p38 kinase pathways inhibitors. Thus, the differential sensitivities to bortezomib corresponded to dissimilar effects on the proteasome, NF-kappaB and AP-1 activities. Inhibition of c-Jun NH(2)-terminal kinase and p38 pathways blocked AP-1 activity and enhanced the antitumor effects. These findings revealed molecular mechanisms of bortezomib sensitivity and resistance, which are under development as biomarkers for clinical trials in patients with HNSCC.

Early phase II trial of oral vorinostat in relapsed or refractory breast, colorectal, or non-small cell lung cancer

Vorinostat (Zolinza) is a histone deacetylase inhibitor that has demonstrated activity in patients with advanced solid tumors in phase I trials. A multicenter, open-label phase II trial of oral vorinostat 200, 300 or 400 mg bid for 14 days followed by a 7-day rest until disease progression or intolerable toxicity was conducted. Patients with measurable, relapsed or refractory breast or non-small cell lung cancer who had received > or = 1 prior therapy or colorectal cancer who had received > or = 2 prior therapies were eligible. The response rate, safety and tolerability were evaluated. Sixteen patients (median age, 62 years; median 5.5 prior therapies) were enrolled. Six patients received 400 mg bid, six received 300 mg bid and four received 200 mg bid (14 days/3 weeks). Dose-limiting toxicities (DLTs) at the 400 or 300 mg bid levels were anorexia, asthenia, nausea, thrombocytopenia, vomiting, and weight loss. No DLTs were observed at the 200 mg bid level. Disease stabilization was observed in eight patients, but there were no confirmed responses. The median TTP was 33.5 days. Eleven patients discontinued due to clinical adverse experiences (AEs). The most common drug-related AEs were anorexia (81%), fatigue (62%), nausea (62%), diarrhea (56%), vomiting (56%), thrombocytopenia (50%) and weight loss (50%). Drug-related AEs > or = grade 3 included thrombocytopenia (50%), anemia (12%), asthenia (12%) and nausea (12%). Vorinostat in a daily oral schedule for 14 days/3 weeks was tolerable at 200 mg bid only, and no responses were observed in this study. Most patients, however, had limited drug exposure which did not allow a reliable efficacy analysis.

Phase II trial of oral vorinostat (suberoylanilide hydroxamic acid) in relapsed diffuse large-B-cell lymphoma

BACKGROUND

Vorinostat has demonstrated activity in refractory cutaneous T-cell lymphoma. In a phase I trial, an encouraging activity in diffuse large-B-cell lymphoma (DLBCL) was noted.

PATIENTS AND METHODS

We carried out a phase II trial (NCT00097929) of oral vorinostat 300 mg b.i.d. (14 days/3 weeks or 3 days/week) in patients with measurable, relapsed DLBCL who had received two or more systemic therapies. Response rate and duration (DOR), time to progression (TTP) and safety were assessed.

RESULTS

Eighteen patients were enrolled (median age: 66 years; median prior therapies: 2). Seven received 300 mg b.i.d. 14 days/3 weeks, but four had grade 3 or 4 toxicity (dose-limiting toxicity, DLT). The schedule was amended to 300 mg b.i.d. 3 days/week), and none had DLT. One achieved a complete response (TtR = 85 days; DOR =or >468 days) and one had stable disease (301 days). Sixteen discontinued for progressive disease; median TTP was 44 days. Median number of cycles was 2 (1 to >19). Common drug-related adverse experiences (AEs; mostly grade 1/2) were diarrhea, fatigue, nausea, anemia and vomiting. Three patients had dose reduction; none discontinued for drug-related AEs. Drug-related AE >or=grade 3 included thrombocytopenia (16.7%) and asthenia (11.1%).

CONCLUSION

Vorinostat was well tolerated at 300 mg b.i.d. 3 days/week or 200 mg b.i.d. 14 days/3 weeks but had limited activity against relapsed DLBCL.

Role of activated nuclear factor-kappaB in the pathogenesis and therapy of squamous cell carcinoma of the head and neck

BACKGROUND

Nuclear factor-kappaB (NF-kappaB), a transcription factor known to modulate expression of factors involved in inflammation, immunity, proliferation, and apoptosis, is constitutively activated and plays a role in pathogenesis and therapeutic resistance in head and neck squamous cell carcinoma (HNSCC). Understanding the molecular alterations leading to aberrant NF-kappaB activation in HNSCC may direct investigators to novel therapeutic targets.

METHODS

Results of laboratory and clinical studies are reviewed.

RESULTS

The structure, function, and activation of NF-kappaB, products of NF-kappaB target genes and their role in HNSCC oncogenesis, and current NF-kappaB modulating interventions are described.

CONCLUSIONS

Aberrant NF-kappaB activation contributes to the expression of oncogenes and the malignant phenotype observed in HNSCC. NF-kappaB, along with providing a link between cancer and inflammation, may serve as an appropriate therapeutic target to inhibit tumor growth and sensitize cancer cells to established cytotoxic anticancer therapies.

Phase IIb multicenter trial of vorinostat in patients with persistent, progressive, or treatment refractory cutaneous T-cell lymphoma

PURPOSE

To evaluate the activity and safety of the histone deacetylase inhibitor vorinostat (suberoylanilide hydroxamic acid) in persistent, progressive, or recurrent mycosis fungoides or Sézary syndrome (MF/SS) cutaneous t-cell lymphoma (CTCL) subtypes.

PATIENTS AND METHODS

Patients with stage IB-IVA MF/SS were treated with 400 mg of oral vorinostat daily until disease progression or intolerable toxicity in this open-label phase IIb trial (NCT00091559). Patients must have received at least two prior systemic therapies at least one of which included bexarotene unless intolerable. The primary end point was the objective response rate (ORR) measured by the modified severity weighted assessment tool and secondary end points were time to response (TTR), time to progression (TTP), duration of response (DOR), and pruritus relief ( > or = 3-point improvement on a 10-point visual analog scale). Safety and tolerability were also evaluated.

RESULTS

Seventy-four patients were enrolled, including 61 with at least stage IIB disease. The ORR was 29.7% overall; 29.5% in stage IIB or higher patients. Median TTR in stage IIB or higher patients was 56 days. Median DOR was not reached but estimated to be >or = 185 days (34+ to 441+). Median TTP was 4.9 months overall, and 9.8 months for stage IIB or higher responders. Overall, 32% of patients had pruritus relief. The most common drug-related adverse experiences (AE) were diarrhea (49%), fatigue (46%), nausea (43%), and anorexia (26%); most were grade 2 or lower but those grade 3 or higher included fatigue (5%), pulmonary embolism (5%), thrombocytopenia (5%), and nausea (4%). Eleven patients required dose modification and nine discontinued due to AE.

CONCLUSION

Oral vorinostat was effective in treatment refractory MF/SS with an acceptable safety profile.

Phase 2 trial of oral vorinostat (suberoylanilide hydroxamic acid, SAHA) for refractory cutaneous T-cell lymphoma (CTCL)

The activity and safety of the histone deacetylase inhibitor vorinostat (suberoylanilide hydroxamic acid, SAHA) were evaluated in patients with refractory cutaneous T-cell lymphoma (CTCL). Group 1 received vorinostat 400 mg daily, group 2 received vorinostat 300 mg twice daily for 3 days with 4 days rest, and group 3 received vorinostat 300 mg twice daily for 14 days with 7 days rest followed by 200 mg twice daily. Treatment continued until disease progression or intolerable toxicity. The primary objective was to determine the complete and partial response (PR) rate. Time to response (TTR), time to progressive disease (TTP), response duration (DOR), pruritus relief, and safety were determined. Thirty-three patients who had received a median of 5 prior therapies were enrolled. Eight patients achieved a PR, including 7 with advanced disease and 4 with Sézary syndrome. The median TTR, DOR, and TTP for responders were 11.9, 15.1, and 30.2 weeks, respectively. Fourteen of 31 evaluable patients had pruritus relief. The most common drug-related AEs were fatigue, thrombocytopenia, diarrhea, and nausea. The most common grade 3 or 4 drug-related AEs were thrombocytopenia and dehydration. Vorinostat demonstrated activity in heavily pretreated patients with CTCL. The 400 mg daily regimen had the most favorable safety profile and is being further evaluated.

A study to determine the effects of food and multiple dosing on the pharmacokinetics of vorinostat given orally to patients with advanced cancer

PURPOSE

This phase I study, conducted in advanced-stage cancer patients, assessed the safety and tolerability of oral vorinostat (suberoylanilide hydroxamic acid), single-dose and multiple-dose pharmacokinetics of vorinostat, and the effect of a high-fat meal on vorinostat pharmacokinetics.

EXPERIMENTAL DESIGN

Patients (n = 23) received single doses of 400 mg vorinostat on day 1 (fasted) and day 5 (fed) with 48 hours of pharmacokinetic sampling on both days. Patients received 400 mg vorinostat once daily on days 7 to 28. On day 28, vorinostat was given (fed) with pharmacokinetic sampling for 24 hours after dose.

RESULTS

The apparent t(1/2) of vorinostat was short (approximately 1.5 hours). A high-fat meal was associated with a small increase in the extent of absorption and a modest decrease in the rate of absorption. A short lag time was observed before detectable levels of vorinostat were observed in the fed state, and T(max) was delayed. Vorinostat concentrations were qualitatively similar following single-dose and multiple-dose administration; the accumulation ratio based on area under the curve was 1.21. The elimination of vorinostat occurred primarily through metabolism, with <1% of the given dose recovered intact in urine. The most common vorinostat-related adverse experiences were mild to moderate nausea, anorexia, fatigue, increased blood creatinine, and vomiting.

CONCLUSIONS

Vorinostat concentrations were qualitatively similar after single and multiple doses. A high-fat meal increased the extent and modestly decreased the rate of absorption of vorinostat; this effect is not anticipated to be clinically meaningful. Continued investigation of 400 mg vorinostat given once daily in phase II and III efficacy studies is warranted.

Variation in cisplatinum sensitivity is not associated with Fanconi Anemia/BRCA pathway inactivation in head and neck squamous cell carcinoma cell lines

Fanconi Anemia has recently been associated with a high risk of head and neck squamous cell carcinoma (HNSCC). Inactivation of the Fanconi Anemia (FANC-BRCA) pathway via promoter methylation of the FANCF gene has been proposed to be responsible for variation in cisplatinum (CDDP) sensitivity seen in ovarian and HNSCCs. Promoter methylation of the FANCF gene has been observed in 15% of HNSCC specimens, but the relationship to FANC pathway activation and CDDP sensitivity has not been reported. In the present study, 10 HNSCC cell lines were examined for expression of nine genes involved in the FANC-BRCA pathway by RT-PCR: FANCA, FANCC, FANCD2, FANCE, FANCF, FANCG, FANCL, BRCA1 and BRCA2. FANC pathway function was evaluated by western blotting for FANCD2 mono-ubiquitination. All of the cell lines were also analyzed for variation in CDDP cytotoxicity. While significant differences were found in CDDP cytotoxicity, Fanconi pathway defects are an infrequent cause, as no evidence of transcriptional down-regulation of FANCF or other FANC mRNAs, or functional FANC-BRCA pathway defects were observed. These findings suggest that the variation in CDDP sensitivity of many HNSCCs is most frequently due to factors other than FANC-BRCA pathway inactivation.

2-methoxyestradiol inhibits hypoxia-inducible factor 1alpha, tumor growth, and angiogenesis and augments paclitaxel efficacy in head and neck squamous cell carcinoma

PURPOSE

Head and neck squamous cell carcinomas have been reported to overexpress hypoxia-inducible factor (HIF)-1alpha, a transcription factor that promotes expression of angiogenesis factors and resistance to programmed and therapy-induced cell death. 2-Methoxyestradiol (2ME2) is a natural compound with HIF-1alpha inhibitory activity that is currently being evaluated in phase 1 and 2 clinical trials for advanced solid tumors and multiple myeloma. To our knowledge, this is the first study to evaluate the effects of 2ME2 in head and neck squamous cell carcinoma.

EXPERIMENTAL DESIGN

In the present study, we investigated the effects of 2ME2 alone and in combination with paclitaxel, an active agent in recurrent or advanced head and neck squamous cell carcinoma.

RESULTS

2ME2 exhibited antiproliferative and cytotoxic effects in a panel of five head and neck squamous cell carcinoma cell lines in the 0.5 to 10 micromol/L range, including induction of G2-M blockade, caspase-3/7 activation, and apoptosis at 48 hours. 2ME2 resulted in decreased nuclear HIF-1alpha-binding activity and affected the expression of downstream genes, such as bid, a proapoptotic bcl-2 family member, and vascular endothelial growth factor, a proangiogenic cytokine. The up-regulation of Bid (57.5% at 12 hours, P < 0.0006) and inhibition of vascular endothelial growth factor secretion (57.7% at 24 hours, P < 0.015; and 50.3% at 48 hours, P < 0.0006) could be partially attributed to the effects on HIF-1alpha, because HIF-1alpha small interfering RNAs produced similar effects. Finally, in vivo, in a xenograft model of head and neck squamous cell carcinoma using UM-SCC-11A cells, 2ME2 exhibited antitumor and antiangiogenic activity, as measured by CD31 immunostaining.

CONCLUSIONS

These results provide support for the use of 2ME2 in combination with paclitaxel for the treatment of recurrent or advanced head and neck squamous cell carcinoma.

Nuclear factor-kappaB is an important modulator of the altered gene expression profile and malignant phenotype in squamous cell carcinoma

We reported previously that transcription factor nuclear factor (NF)-kappaB is constitutively activated in human and murine squamous cell carcinomas (SCCs). The role of NF-kappaB in the cumulative changes in gene expression with transformation and progression of the murine SCC Pam 212 and after switching off NF-kappaB by a dominant negative inhibitor kappaB mutant (IkappaBalphaM) was explored by profiling with a 15,000-element cDNA micoarrray. Remarkably, NF-kappaB modulated the expression of >60% of the 308 genes differentially expressed between normal keratinocytes and metastatic SCCs. NF-kappaB directly or indirectly modulated expression of programs of genes functionally linked to proliferation, apoptosis, adhesion, and angiogenesis. Among these, changes in expression of cyclin D1, inhibitor of apoptosis-1, mutant Trp53, and beta-catenin detected with modulation of NF-kappaB by microarray were confirmed by Western and Northern blot. NF-kappaB DNA binding motifs were detected in the promoter of approximately 63% of genes showing increased expression and 33% of the genes showing decreased expression. The ACTACAG motif implicated in the NF-kappaB-dependent down-regulation of mRNA expression of MyoD and Sox9 was detected in the coding portion of about 15% of genes showing increased or decreased expression. Inactivation of NF-kappaB inhibited malignant phenotypic features including proliferation, cell survival, migration, angiogenesis, and tumorigenesis. These results provide evidence that NF-kappaB is an important modulator of gene expression programs that contribute to the malignant phenotype of SCC.

Multiorgan mRNA misexpression in murine autosomal recessive polycystic kidney disease

BACKGROUND

BALB/c mice homozygous for the cpk mutation develop a form of polycystic kidney disease (PKD) with multiorgan pathology similar to human autosomal recessive PKD. Messenger RNA expression in multiple affected organs was analyzed to determine if common gene cascades were misexpressed in the cystic kidney and extrarenal sites of disease. In cystic kidneys, misexpressed mRNAs were found in one of four general groups: proliferation/cell growth, apoptosis, differentiation or extracellular matrix.

METHODS

RNA was isolated from kidney, liver and pancreas of cystic and normal BALB/c-cpk mice. Using Northern blot hybridization and ribonuclease protection assays (RPA), the expression of several genes thought to be associated with PKD, namely c-myc, epidermal growth factor receptor (EGF-R) and PKD-1, were evaluated. RPAs were used to assess mRNA expression of cyclins and members of the bax/bcl-2 family. In addition, kidney, liver and pancreas were immunostained for c-Myc and PCNA.

RESULTS

Cystic kidney, liver and pancreas all exhibited similar patterns of mRNA misexpression of c-myc, EGF-R and PKD-1. In addition, a number of cell proliferation and apoptosis-related mRNAs also were elevated in cystic kidney and pancreas. Renal epithelial cells expressing proliferation-associated proteins [c-Myc and proliferating cell nuclear antigen (PCNA)] were nearly absent in normal kidney; however, cells of cystic and non-cystic renal tubules plus liver and pancreatic cyst exhibited an increased number of nuclei labeled with antibodies to these proteins.

CONCLUSIONS

These data suggest that similar pathologic mechanisms (including the expression of c-myc, EGF-R, PKD-1, cyclin, and bax/bcl-2 family mRNAs) may be responsible for the development of cystic changes in kidney, liver and pancreas in murine autosomal recessive PKD. Treatments targeting these similarly misexpressed mRNAs may be efficacious in ameliorating the cystic pathology in the kidney as well as the other affected organs in ARPKD.

c-myc antisense oligonucleotide treatment ameliorates murine ARPKD

BACKGROUND

Overexpression of c-myc is postulated to play a role in the pathogenesis of polycystic kidney disease (PKD). c-myc expression is increased in all rodent models of PKD that have been examined as well as in human ADPKD. To determine whether overexpression of renal c-myc contributes to renal cyst formation, C57BL/6J-cpk litters (an animal model of ARPKD) were treated with an antisense oligomer (ASO) to c-myc mRNA.

METHODS

Injections of 30 microg of a c-myc ASO were given to C57BL/6J-cpk litters on postnatal days 7-20. Control mice received either sham injections or injections of an equal amount of a scrambled ASO. At 20 days, kidney weight, body weight, serum urea nitrogen (SUN), hematocrit, and renal concentration of ASO were determined. In kidney, c-Myc and PCNA protein were assessed by immunoblotting and steady state levels of renal RNA for c-myc, EGF, SGP-2, and histone H4 were assessed by northern blot hybridization. c-Myc and PCNA proteins were localized by immunohistochemistry.

RESULTS

Cystic mice treated with the c-myc ASO had a decreased relative kidney weight, improved renal function, and a reduced amount of cystic change compared with sham and scrambled ASO controls. The abnormal expression of several PKD related proteins and mRNAs were partially reversed by c-myc antisense treatment. c-myc staining appeared to be reduced in the noncystic tubules. Treatment with the c-myc ASO did not cause a reduction in hematocrit or total body weight indicating that the beneficial effects were not due to a generalized inhibition of cell proliferation in rapidly growing tissue.

CONCLUSIONS

c-Myc appears to play a role in the cystogenesis of cpk-induced murine PKD and antisense targeting the overexpression of c-myc partially ameliorated the renal changes.

Development of autosomal recessive polycystic kidney disease in BALB/c-cpk/cpk mice

Autosomal recessive polycystic kidney disease (ARPKD) is a rare but devastating inherited disease in humans. Various strains of mice that are homozygous for the cpk gene display renal pathology similar to that seen in human ARPKD. The PKD progresses to renal insufficiency, azotemia, and ultimately a uremic death by approximately 3 wk of age. This study characterizes PKD in mice that are homozygous for the cpk gene on a BALB/c inbred mouse background. The BALB/c-cpk/cpk murine model displays renal as well as extrarenal pathology similar to that found in human ARPKD. The renal pathology includes the well-characterized early proximal tubule and, later, massive collecting duct cysts. The extrarenal defects in this murine model include common bile duct dilation, intrahepatic biliary duct cysts with periductal hyperplasia, and pancreatic dysplasia with cysts. Renal mRNA expression of c-myc, a proto-oncogene, and clusterin (SGP-2), a marker associated with immature collecting ducts, decreases during normal development but is upregulated in murine ARPKD. Expression of epidermal growth factor (EGF) mRNA is significantly diminished, whereas EGF receptor mRNA is upregulated in the BALB/c-cpk/cpk kidney compared with phenotypically normal littermates. To determine whether the altered EGF expression contributes to the development of PKD, neonatal mice were treated with exogenous EGF (1 microg/g body wt injected subcutaneously on postnatal days 3 through 9). EGF treatment reduced the relative kidney weight and common bile duct dilation and downregulated renal expression of clusterin and EGF receptor. However, exogenous EGF did not affect the degree of renal failure, the pancreatic pathology, or the misregulated renal expression of c-myc. In summary, the present study characterizes the renal and extrarenal pathology in the BALB/c-cpk/cpk murine model of ARPKD. Renal mRNA expression of EGF is diminished in this mouse model. EGF treatment did not prevent renal failure but ameliorated pathologic changes in the kidney and the biliary ducts of the BALB/c-cpk/cpk mouse.