AZD6244 With Cetuximab for Solid Tumors and Colorectal Cancer

Background:

• AZD6244 is an oral highly selective and potent uncompetitive inhibitor of mitogen-activated protein kinase 1/2 (MEK1/2).
• The presence of KRAS mutations predict resistance to EGFR-directed antibody therapy of metastatic colorectal cancer. This appears secondary to KRAS activation of signaling cascades downstream of the EGFR receptor, including the RAF/MEK/ERK pathway.
• Our hypothesis is that EGFR inhibition by cetuximab would be augmented in patients with KRAS mutations if activation of the RAF/MEK/ERK cascade were to be inhibited.

Objectives:

• To determine the dose limiting toxicities and the maximum tolerated dose of AZD6244 in combination with cetuximab in advanced, refractory solid tumors.
• To assess for evidence of anti-tumor activity with this combination, per tumor measurements using RECIST criteria.
• To evaluate the pharmacokinetics of AZD6244 and cetuximab when administered concomitantly.
• To evaluate the safety and tolerability of the combination of AZD6244 and cetuximab in patients with K-RAS mutated metastatic colorectal cancer.
• To assess the inhibition of the RAF/MEK/ERK pathway in peripheral blood mononuclear cells secondary to treatment with AZD6244.
• To evaluate the pharmacokinetics of AZD6244 in combination with cetuximab and the relation to treatment side effects.

Eligibility:

• Patients must have histologically confirmed malignancy that is metastatic or unresectable and for which standard curative or palliative measures do not exist or are no longer effective. In the MTD expansion cohort: Patients must have biopsy proven K-RAS mutant, metastatic colorectal cancer.
• Age greater than or equal to 18
• ECOG performance status less than or equal to 2

Study Design:

• This is a phase 1 dose escalation study of AZD6244 in combination with fixed-dose cetuximab with an expanded cohort in K-RAS mutated metastatic colorectal cancer.
• Patients will be treated with AZD6244 orally twice daily continuously, and cetuximab will be administered at standard doses on days 1, 8, 15 and 22. Dose escalations are outlined per the schema in the parent protocol.
• The dose of AZD6244 will be escalated using a 3-patient cohort design based on first cycle toxicities until dose limiting toxicities (DLT) and maximum tolerated dose (MTD) are defined. Once the MTD/RP2D has been identified, an additional 12 patients with K-RAS mutant colorectal cancer will be enrolled at that dose level, in an effort to more fully characterize pharmacokinetic characteristics of this combination. If at least an 8% response rate is observed in the expanded cohort, the combination will be recommended for future analysis.

• INCLUSION CRITERIA:
• In the dose escalation cohorts: Patients must have histologically confirmed malignancy that is metastatic or unresectable and for which standard curative or palliative measures do not exist or are no longer effective. Histology can be based on either the primary tumor or metastases.
• In the MTD expansion cohort: Patients must have biopsy proven K-RAS mutant, metastatic colorectal cancer that has progressed on at least 2 prior standard therapies. K-RAS mutation status must be verified by a CLIA-certified laboratory. (NOTE: colorectal patients enrolled during the dose escalation portion do not need to be K-RAS mutant in order to be eligible).
• Patients must be at least 4 weeks since prior chemotherapy, 6 weeks if the last regimen included nitrosureas or mitomycin C. Prior radiation is allowed as long as the radiation was completed 4 weeks prior to study treatment and no more than 35% of marrow irradiated.
• Age greater than or equal to18 years. Because no dosing or adverse event data are currently available on the use of AZD6244 in combination with cetuximab in patients less than 18 years of age, children are excluded from this study, but will be eligible for future pediatric phase 1 combination trials.
• ECOG performance status less than or equal to 2 (Karnofsky >60%).
• Life expectancy of greater than 3 months.
• Patients must have normal organ and marrow function as defined below:

• Leukocytes greater than or equal to 3,000/mcL
• absolute neutrophil count greater than or equal to 1,500/mcL
• platelets greater than or equal to 100,000/mcL
• total bilirubin within normal institutional limits
• AST(SGOT)/ALT(SGPT) less than or equal to 2.5 X institutional upper limit of normal (AST and ALT less than or equal to 5.0 X institutional upper limit of normal will be permitted if liver metastases are present)
• creatinine less than or equal to to to1.5X institution upper limit of normal OR creatinine clearance greater than or equal to 45 mL/min/1.73 m2, as calculated by Cockroft-Gault formula, for patients with creatinine levels above institutional normal. May use a 24 hr. urine collection to determine creatinine clearance.
• Patients may have received prior cetuximab.
• Patients with brain metastases that have been treated and stable for 2 months will be eligible for this study.
• Subjects undergoing anti-coagulation therapy with LMWH and warfarin are eligible. Subjects receiving both warfarin and AZD6244 should have more frequent PT/INR monitoring (see section 10.0)

Exclusion criteria

• Patients who have had chemotherapy, radiotherapy or hormonal therapy within 4 weeks (6 weeks for nitrosoureas or mitomycin C) prior to entering the study or those who have not recovered (less than or equal to grade 1) from adverse events due to agents administered more than 4 weeks earlier.
• Concurrent treatment with an investigational agent other than the investigational agent(s) used in this study OR treatment within 4 weeks of study entry with any investigational agent(s) or device(s).
• Failure to recover fully (as judged by the investigator) from prior surgical procedures.
• History of allergic reactions attributed to compounds of similar chemical or biologic composition to AZD6244 or other agents used in study.
• Patients taking high doses (more than recommended daily dose) of vitamin E will be excluded. Patients can discontinue use of high dose vitamin E prior to study entry to be considered eligible.
• Any condition (e.g., gastrointestinal tract disease resulting in an inability to take oral medication or a requirement for IV alimentation, prior surgical procedures affecting absorption, or active peptic ulcer disease) that impairs their ability to swallow and retain AZD6244 capsules.
• Patients with malabsorption syndrome, disease significantly affecting gastrointestinal function, or resection of the stomach or small bowel are excluded. Subjects with ulcerative colitis, inflammatory bowel disease, or a partial or complete small bowel obstruction are also excluded.
• Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, uncontrolled hypertension, prior cardiomyopathy, LVEF less than 50%, unstable angina pectoris, cardiac arrhythmia (i.e. atrial fibrillation), or psychiatric illness/social situations that would limit compliance with study requirements.
• Pregnant women are excluded from this study because AZD6244 is a small molecule kinase inhibitor with the potential for teratogenic or abortifacient effects. Because there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with AZD6244, breastfeeding should be discontinued if the mother is treated with AZD6244. These potential risks may also apply to other agents used in this study.
• HIV-positive patients on combination antiretroviral therapy are ineligible because of the potential for pharmacokinetic interactions with AZD6244. In addition, these patients are at increased risk of lethal infections when treated with marrow-suppressive therapy. Appropriate studies will be undertaken in patients receiving combination antiretroviral therapy when indicated.
• Patients who are serologically positive for Hepatitis B or C, or have a history of liver disease, other forms of hepatitis or cirrhosis are ineligible.
• Use of strong CYP1A2 or 3A4 inducers and/or inhibitors (for example, but not limited to, ketoconazole, rifampacin, atazanavir, clarithromycin, indinavir, itraconazole, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, troleandomycin (TAO), voriconazole, grapefruit or grapefruit juice, ifabutin, rifapentine, phenytoin, carbamazepine, phenobarbital and St. John's Wort) is not permitted while on study or within 7 days prior to study enrollment.