Cabozantinib and Panitumumab for RAS Wild-Type Metastatic Colorectal Cancer.

LESSONS LEARNED: Antitumor activity was observed in the study population. Dose modifications of cabozantinib improve long-term tolerability. Biomarkers are needed to identify patient populations most likely to benefit. Further study of cabozantinib with or without panitumumab in patients with metastatic colorectal cancer is warranted. BACKGROUND: The epidermal growth factor receptor (EGFR) antibody panitumumab is active in patients with RAS wild-type (WT) metastatic colorectal cancer (mCRC), but nearly all patients experience resistance. MET amplification is a driver of panitumumab resistance. Cabozantinib is an inhibitor of multiple kinases, including vascular endothelial growth factor receptor 2 (VEGFR2) and c-MET, and may delay or reverse anti-EGFR resistance. METHODS: In this phase Ib clinical trial, we established the maximum tolerated dose (MTD) and recommended phase II dose (RP2D) of cabozantinib and panitumumab. We then treated an expansion cohort to further describe the tolerability and clinical activity of the RP2D. Eligibility included patients with KRAS WT mCRC (later amended to include only RAS WT mCRC) who had received prior treatment with a fluoropyrimidine, oxaliplatin, irinotecan, and bevacizumab. RESULTS: Twenty-five patients were enrolled and treated. The MTD/RP2D was cabozantinib 60 mg p.o. daily and panitumumab 6 mg/kg I.V. every 2 weeks. The objective response rate (ORR) was 16%. Median progression free survival (PFS) was 3.7 months (90% confidence interval [CI], 2.3-7.1). Median overall survival (OS) was 12.1 months (90% CI, 7.5-14.3). Five patients (20%) discontinued treatment due to toxicity, and 18 patients (72%) required a dose reduction of cabozantinib. CONCLUSION: The combination of cabozantinib and panitumumab has activity. Dose reductions of cabozantinib improve tolerability.

A phase Ib study of capecitabine and ziv-aflibercept followed by a phase II single-arm expansion cohort in chemotherapy refractory metastatic colorectal cancer.

BACKGROUND: Patients with chemotherapy refractory metastatic colorectal cancer (CRC) have a poor prognosis and limited therapeutic options. In this phase Ib/II clinical trial, we established the maximum tolerated dose (MTD) and recommended phase II dose (RPTD) for the combination of capecitabine and ziv-aflibercept, and then we evaluated the efficacy of the combination in patients with chemotherapy refractory metastatic CRC. METHODS: All patients were required to have a Karnofsky Performance Status > 70% and adequate organ function. The phase Ib dose escalation cohort included patients with advanced solid tumors who had progressed on all standard therapies. Using a standard 3 + 3 design, we identified the MTD and RPTD for the combination. Fifty patients with metastatic CRC who had progressed on or were intolerant of a fluoropyrimidine, oxaliplatin, irinotecan, and bevacizumab were then enrolled in a single-arm phase II expansion cohort, and were treated at the RPTD. Prior EGFR antibody therapy was required for subjects with RAS wildtype tumors. The primary endpoint for the expansion cohort was progression-free survival (PFS) at two months. Secondary endpoints included objective response rate (ORR) and overall survival (OS). RESULTS: A total of 63 patients were enrolled and evaluable for toxicity (13 dose escalation; 50 expansion). The MTD and RPTD were: capecitabine 850 mg/m2, P.O. bid, days 1-14, and ziv-aflibercept 6 mg/kg I.V., day 1, of each 21-day cycle. In the expansion cohort, 72% of patients were progression-free at two months (95% confidence interval [CI], 60-84%). Median PFS and OS were 3.9 months (95% CI, 2.3-4.5) and 7.1 months (95% CI: 5.8-10.0), respectively. Among all patients evaluable for toxicity, the most common treatment related adverse events (all grade [%]; grade ≥ 3 [%]) included palmar-plantar erythrodysesthesia (41%; 6%), hypertension (33%; 22%), and mucositis (19%; 5%). RNA was isolated from archived tumor specimens and gene expression analyses revealed no association between angiogenic biomarkers and clinical outcomes. CONCLUSION: The combination of capecitabine and ziv-aflibercept at the RPTD demonstrated acceptable safety and tolerability. PFS at 2 months in patients with chemotherapy refractory metastatic CRC was significantly greater than that in historical controls, indicating that this combination warrants further study. TRIAL REGISTRATION: This clinical trial was registered in the www.clinicaltrials.gov system as NCT01661972 on July 31, 2012.

A phase I study of gemcitabine + dasatinib (gd) or gemcitabine + dasatinib + cetuximab (GDC) in refractory solid tumors.

PURPOSE: This study was conducted to define the maximum tolerated dose (MTD), recommended phase two dose (RPTD), and toxicities of gemcitabine + dasatinib (GD) and gemcitabine + dasatinib + cetuximab (GDC) in advanced solid tumor patients. METHODS: This study was a standard phase I 3 + 3 dose escalation study evaluating two combination regimens, GD and GDC. Patients with advanced solid tumors were enrolled in cohorts of 3-6 to either GD or GDC. Gemcitabine was dosed at 1000 mg/m2 weekly for 3 of 4 weeks, dasatinib was dosed in mg PO BID, and cetuximab was dosed at 250 mg/m2 weekly after a loading dose of cetuximab of 400 mg/m2. There were two dose levels for dasatinib: (1) gemcitabine + dasatinib 50 mg ± cetuximab, and (2) gemcitabine + dasatinib 70 mg ± cetuximab. Cycle length was 28 days. Standard cycle 1 dose-limiting toxicity (DLT) definitions were used. Eligible patients had advanced solid tumors, adequate organ and marrow function, and no co-morbidities that would increase the risk of toxicity. Serum, plasma, and skin biopsy biomarkers were obtained pre- and on-treatment. RESULTS: Twenty-five patients were enrolled, including 21 with pancreatic adenocarcinoma. Three patients received prior gemcitabine. Twenty-one patients were evaluable for toxicity and 16 for response. Four DLTs were observed: Grade (Gr) 3 neutropenia (GDC1, n = 1), Gr 3 ALT (GD2, n = 2), and Gr 5 pneumonitis (GDC2, n = 1). Possible treatment-emergent adverse events (TEAEs) in later cycles included: Gr 3-4 neutropenia (n = 7), Gr 4 colitis (n = 1), Gr 3 bilirubin (n = 2), Gr 3 anemia (n = 2), Gr 3 thrombocytopenia (n = 2), Gr 3 edema/fluid retention (n = 1), and Gr 3 vomiting (n = 3). Six of 16 patients (3 of whom were gemcitabine-refractory) had stable disease (SD) as best response, median duration = 5 months (range 1-7). One gemcitabine-refractory patient had a partial response (PR). Median PFS was 2.9 months (95% CI 2.1, 5.8). Median OS was 5.8 months (95% CI 4.1, 11.8). Dermal wound biopsies demonstrated that dasatinib resulted in a decrease of total and phospho-Src levels, and cetuximab resulted in a decrease of EGFR and ERBB2 levels. CONCLUSIONS: The MTD/RPTD of GD is gemcitabine 1000 mg/m2 weekly for 3 of 4 weeks and dasatinib 50 mg PO BID. The clinical activity of GD seen in this study was modest, and does not support its further investigation in pancreatic cancer.

A Phase I Trial of the IGF-1R Antibody Ganitumab (AMG 479) in Combination with Everolimus (RAD001) and Panitumumab in Patients with Advanced Cancer.

PURPOSE: This study evaluated the maximum tolerated dose or recommended phase II dose (RPTD) and safety and tolerability of the ganitumab and everolimus doublet regimen followed by the ganitumab, everolimus, and panitumumab triplet regimen. MATERIALS AND METHODS: This was a standard 3 + 3 dose escalation trial. Doublet therapy consisted of ganitumab at 12 mg/kg every 2 weeks; doses of everolimus were adjusted according to dose-limiting toxicities (DLTs). Panitumumab at 4.8 mg/kg every 2 weeks was added to the RPTD of ganitumab and everolimus. DLTs were assessed in cycle 1; toxicity evaluation was closely monitored throughout treatment. Treatment continued until disease progression or undesirable toxicity. Pretreatment and on-treatment skin biopsies were collected to assess insulin-like growth factor 1 receptor and mammalian target of rapamycin (mTOR) target modulation. RESULTS: Forty-three subjects were enrolled. In the doublet regimen, two DLTs were observed in cohort 1, no DLTs in cohort -1, and one in cohort -1B. The triplet combination was discontinued because of unacceptable toxicity. Common adverse events were thrombocytopenia/neutropenia, skin rash, mucositis, fatigue, and hyperglycemia. In the doublet regimen, two patients with refractory non-small cell lung cancer (NSCLC) achieved prolonged complete responses ranging from 18 to >60 months; one treatment-naïve patient with chondrosarcoma achieved prolonged stable disease >24 months. In dermal granulation tissue, the insulin-like growth factor receptor and mTOR pathways were potently and specifically inhibited by ganitumab and everolimus, respectively. CONCLUSION: The triplet regimen of ganitumab, everolimus, and panitumumab was associated with unacceptable toxicity. However, the doublet of ganitumab at 12 mg/kg every 2 weeks and everolimus five times weekly had an acceptable safety profile and demonstrated notable clinical activity in patients with refractory NSCLC and sarcoma. IMPLICATIONS FOR PRACTICE: This trial evaluated the maximum tolerated dose or recommended phase II dose and safety and tolerability of the ganitumab and everolimus doublet regimen followed by the ganitumab, everolimus, and panitumumab triplet regimen. Although the triplet regimen of ganitumab, everolimus, and panitumumab was associated with unacceptable toxicity, the doublet of ganitumab at 12 mg/kg every 2 weeks and everolimus at five times weekly had an acceptable safety profile and demonstrated notable clinical activity in patients with refractory non-small cell lung cancer and sarcoma.

Phase I study of dasatinib in combination with capecitabine, oxaliplatin and bevacizumab followed by an expanded cohort in previously untreated metastatic colorectal cancer.

PURPOSE: Dasatinib inhibits src family kinases and has anti-angiogenic properties. We conducted a phase I study of dasatinib, capecitabine, oxaliplatin, and bevacizumab (CapeOx/bevacizumab), with an expansion cohort in metastatic colorectal cancer (CRC). METHODS: Patients were enrolled in a dose escalation cohort to establish the maximum tolerated dose (MTD) and the recommended phase II dose (RP2D). Using a "3 + 3" design, twelve patients with advanced solid tumors received dasatinib (50 mg twice daily or 70 mg daily), capecitabine (850 mg/m(2) twice daily, days 1-14), oxaliplatin (130 mg/m(2) on day 1) and bevacizumab (7.5 mg/kg on day1), every 3 weeks. Ten patients with previously untreated metastatic CRC were then enrolled in an expansion cohort. Activated src (src(act)) expression was measured by immunohistochemistry, using an antibody that selectively recognizes the active conformation of src (clone 28). RESULTS: Twenty-two patients were enrolled between June 2009 and May 2011. Two DLTs were observed in the 50 mg bid dasatinib cohort, and one DLT was observed in the 70 mg daily dasatinib cohort. The MTD and RP2D for dasatinib was 70 mg daily. The most common treatment-related adverse events were fatigue (20; 91 %) and diarrhea (18; 82 %). Biomarker analysis of src(act) expression demonstrated that the overall response rate (ORR) was 75 % (6/8) for patients with high src(act) expression (IHC ≥ 2), compared to 0 % (0/8) for patients with low srcact expression (IHC 0 or 1); (p = 0.007). CONCLUSIONS: The RP2D of dasatinib is 70 mg daily in combination with CapeOx/bevacizumab. High levels of srcact expression may predict those patients most likely to benefit from dasatinib.

Phase I study of bevacizumab, everolimus, and panobinostat (LBH-589) in advanced solid tumors.

PURPOSE: To define the maximum tolerated dose, clinical toxicities, and pharmacodynamics of bevacizumab, everolimus, and panobinostat (LBH-589) when administered in combination to patients with advanced solid tumor malignancies. EXPERIMENT DESIGN: Subjects received 10 mg of panobinostat three times weekly, 5 or 10 mg everolimus daily, and bevacizumab at 10 mg/kg every 2 weeks. Dose-limiting toxicities (DLTs) were assessed in cycle 1; toxicity evaluation was closely monitored throughout treatment. Treatment continued until disease progression or undesirable toxicity. Protein acetylation was assessed in peripheral blood mononuclear cells (PBMC) both at baseline and on treatment. RESULTS: Twelve subjects were evaluable for toxicity and nine subjects for response. DLTs in cohort 1 included grade 2 esophagitis and grade 3 oral mucositis; DLTs in cohort -1 were grade 2 ventricular arrhythmia and grade 2 intolerable skin rash. Common adverse events were diarrhea (50 %), headache (33 %), mucositis/stomatitis (25 %), hyperlipidemia (25 %), and thrombocytopenia (25 %). There was 1 partial response; an additional 2 subjects had stable disease as best response. No consistent changes in protein acetylation in PBMC were observed in samples available from eight patients on treatment compared with baseline. CONCLUSIONS: Bevacizumab, everolimus, and panobinostat in combination at the lowest proposed doses did not have an acceptable safety and tolerability profile and did not consistently inhibit HDAC activity; therefore, we do not recommend further evaluation.

A phase I-II study of docetaxel and atrasentan in men with castration-resistant metastatic prostate cancer.

PURPOSE: The primary aims of this phase I-II study were to determine the maximum tolerated dose, dose-limiting toxicity, pharmacokinetics, and preliminary efficacy of the combination of docetaxel and the endothelin A receptor antagonist atrasentan as first-line treatment for men with metastatic castration-resistant prostate cancer. EXPERIMENTAL DESIGN: Patients were treated with docetaxel at doses ranging from 60 to 75 mg/m(2) every 21 days, with daily oral atrasentan 10 mg starting on day 3. Patients were treated until evidence of disease progression or unacceptable toxicity. RESULTS: Thirty-one patients were enrolled over three docetaxel dose levels (8 at 60 mg/m(2), 19 at 70 mg/m(2), and 4 at 75 mg/m(2)) including dose expansion at 70 mg/m(2). The maximum tolerated dose of docetaxel was 70 to 75 mg/m(2). Drug-related grade 3-4 toxicities included neutropenia (50-63%) and febrile neutropenia (16-25%); other grade 1-2 toxicities included fatigue, peripheral edema, diarrhea, headache, rhinitis, anorexia, and nausea. Confirmed prostate-specific antigen (PSA) responses were observed in 23% [95% confidence interval (95% CI), 10-41%]; the rate of >30% declines in PSA was 35% (95% CI, 19-55%). Median overall survival was 17.6 months (95% CI, 13.0-23.2) and median progression-free survival was 4.2 months (95% CI, 2.3-5.8). Significant declines in bone alkaline phosphatase and serum N-telopeptides were observed with therapy. CONCLUSIONS: The maximum tolerated dose of every-3-week docetaxel with 10 mg atrasentan is 70 to 75 mg/m(2). Overall survival and progression-free survival are comparable to that seen with docetaxel and prednisone, whereas the rates of PSA decline are slightly lower than expected. A phase III study of this combination with prednisone has been initiated and is ongoing.

Long-term treatment with bevacizumab for patients with metastatic colorectal cancer: case report.

Bevacizumab is a monoclonal antibody to vascular endothelial growth factor that has demonstrated increased overall survival when added to standard chemotherapy regimens for metastatic colorectal cancer. Herein we report the cases of 2 patients who demonstrated prolonged survival times of almost 5 and 6 years, respectively, on various chemotherapy regimens that also included bevacizumab. Throughout most of their disease course, these patients maintained a good quality of life, with some adjustments of chemotherapy doses because of side effects. Bevacizumab was generally well tolerated in long-term use.