Study of the Pan-DAC Inhibitor AR-42 and Pazopanib in Advanced Sarcoma and Kidney Cancer

This phase 1 study was developed to identify recommended phase 2 doses (RP2Ds) of AR-42 and pazopanib when given in combination for subsequent clinical trials and may have potentially identified candidate pharmacodynamic and predictive biomarkers.

This study was a single-arm, open-label, dose escalation phase 1 trial to determine the RP2Ds of AR-42 and pazopanib when given in combination to patients with advanced Renal Cell Carcinoma (RCC) or Soft Tissue Sarcoma (STS). Eligible patients had recurrent, unresectable, or metastatic RCC or STS for which pazopanib was an appropriate therapy.

AR-42 was taken orally once per day on 3 non-consecutive days each week during the first 3 weeks of each 4-week cycle. Pazopanib was taken by mouth once daily continuously during each cycle.

A modified 3+3 dose-escalation design was to be followed until the maximum tolerated doses (MTDs) were determined. The initial cohort of patients were assigned to an AR-42 dose of 20 mg taken once per day on 3 non-consecutive days during the first 3 weeks of each 4-week cycle and a pazopanib dose of 600 mg once daily continuously. Additional patients would be enrolled until a total of 12 patients were treated at the MTDs.

The protocol specifies a dose escalation plan that initially impacts only the pazopanib dose. The starting dose of pazopanib (600 mg) was planned to be escalated early so that the FDA-approved full dose of pazopanib (800 mg) would be reached before escalating the AR-42 dose. In subsequent dose-escalation steps, the dose of AR-42 was planned to be increased in 10-mg increments from a starting dose of 20 mg to a maximum dose of 40 mg.

If the number of Dose-Limiting Toxicities (DLT) showed that the MTD was exceeded with a pazopanib dose of 800 mg , the pazopanib dose was planned to be decreased to 600 mg and the AR-42 dose increased in 10-mg increments regardless of relationship of the DLT to one or both study medications.

Toxicities were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events Version 4.0 (NCI CTCAE v4.0). The DLT evaluation period was the first treatment cycle. A minimum of 6 doses of AR-42 and 21 doses of pazopanib were required for a patient to be DLT-evaluable (if DLT was not observed with the delivered dose). DLT was defined as any ≥ grade 3 toxicity occurring during the DLT evaluation period and attributed to one or both of the study medications EXCEPT the following:

* The first incidence of grade 3 PPE at any dose level (subsequent incidences of grade 3 PPE will be considered DLT)
* Grade 3 nausea and vomiting in the absence of adequate prophylaxis and/or responsive to medical management within 48 hours
* Grade 3 diarrhea in the absence of adequate prophylaxis and/or responsive to medical management within 48 hours
* Grade 3 fatigue responsive to medical management • Grade 3 asymptomatic hypertension lasting ≤ 7 days
* Grade 3 electrolyte abnormalities that are corrected within 48 hours and, when corrected, can be maintained
* Grade 3 asymptomatic lipase elevation lasting ≤ 7 days
* Grade 3 decrease in platelet count if no clinically significant hemorrhage has occurred
* Grades 3 and 4 decrease in white blood cell count
* Grade 3 decrease in neutrophil count
* Grade 4 decrease in neutrophil count lasting ≤ 7 days
* Grades 3 and 4 decrease in lymphocyte count

Dose escalation was planned to continue until the maximum-tolerated dose (MTD), defined as one dose level below the dose in which dose-limiting toxicities (DLTs) are observed in \>1 of the participants (e.g., in at least 2 participants in a cohort of at least 3). In the cohort of 12 patients at the MTD, no more than 3 DLTs were allowed to confirm the MTD. The RP2D was defined as equal to or less than the MTD, with an allowance to consider an RP2D below the MTD given the overall tolerability of the regimen including the frequency of AEs that were not DLTs and the frequency of dose modifications.

Eligibility Criteria:
Inclusion Criteria:

* Recurrent, unresectable, or metastatic Renal Cell Carcinoma (RCC) or Soft Tissue Sarcoma (STS) (any histologic type) for which pazopanib was an appropriate therapy
* Measurable or evaluable disease by Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST v1.1)
* Age ≥ 18 years
* Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
* Adequate bone marrow function as defined below:

  * Absolute neutrophil count (ANC) ≥ 1200/mm3
  * Platelets ≥ 120,000/mm3
  * Hemoglobin ≥ 9.5 g/dL
* Adequate renal function as defined below:

  * Creatinine ≤ 1.5 x upper limit of normal (ULN) for the laboratory or calculated or actual creatinine clearance ≥ 60 mL/min
  * Proteinuria ≤ 2+ \[100 mg/dL\] (using a random urine sample or \< 3.0 gm using a 24-hour sample) (Note: If urine sample indicates ≥ 2+ \[100 mg/dL\]), a 24-hour urine sample must be collected and tested; urine protein in the 24-hour sample must be \< 3.0 gm/24 hours.)
* Adequate hepatic function as defined below:

  * Total bilirubin ≤ 1.5 x ULN for the laboratory (Note: Patients with known Gilbert's Syndrome were not eligible for this study)
  * Aspartate aminotransferase (AST) ≤ 2.5 x ULN for the laboratory
  * Alanine aminotransferase (ALT) ≤ 2.5 x ULN for the laboratory
* Non-hematologic toxicities from previous cancer therapies resolved to ≤ grade 1
* International normalized ratio (INR) ≤ 1.5
* Activated partial thromboplastin time (aPTT) ≤ 1.5 x ULN for the laboratory
* Left ventricular ejection fraction (LVEF) assessment (eg, echocardiogram, MUGA scan, first-pass technique) performed within 3 months prior to initiation of study treatment indicates an LVEF of ≥ 50%
* A woman of childbearing potential (WCBP), defined as a woman who was \< 60 years of age and had not had a hysterectomy, must have had a documented negative serum pregnancy test within 7 days prior to initiating study treatment
* A WCBP and a male patient with a partner who was a WCBP must have agreed to use a medically accepted method for preventing pregnancy for the duration of study treatment and for 2 months following completion of study treatment
* Ability to have understood and willingness to have signed the consent form

Exclusion Criteria:

* Symptomatic or untreated brain metastasis
* Leptomeningeal metastasis
* Any investigational agent within 4 weeks prior to initiating study treatment
* Previous therapy with pazopanib
* Inability to swallow medication
* Known or suspected malabsorption condition or obstruction
* Contraindication to antiangiogenic agents, including:

  * Serious non-healing wound, non-healing ulcer, or bone fracture
  * Major surgical procedure or significant traumatic injury within 4 weeks prior to initiating study treatment; other surgical procedures within 2 weeks prior to initiating study treatment
  * Pulmonary hemorrhage/bleeding event ≥ grade 2 within 12 weeks prior to initiating study treatment
  * Any other hemorrhage/bleeding event ≥ grade 3 within 12 weeks prior to initiating study treatment
* History of organ allograft including corneal transplant
* Evidence of bleeding diathesis or coagulopathy
* Documented Gilbert's Syndrome
* Resting systolic blood pressure (BP) \< 100 mmHg
* Hypertension defined as systolic BP ≥ 140 mmHg or diastolic BP ≥ 90 mmHg despite optimal medical management
* QTc interval \> 450 ms on screening 12-lead electrocardiogram (ECG)

  * If baseline QTc on screening ECG met exclusion criteria:

    * Check calcium, potassium, and magnesium serum levels.
    * Correct any identified hypocalcemia, hypokalemia, and/or hypomagnesemia and repeat ECG to reconfirm exclusion of patient due to prolonged QTc interval.
  * For patients with heart rate (HR) 60-100 bpm, manual read of QTc was not required.
  * For patients with a baseline HR \< 60 bpm or \> 100 bpm, manual read of the QT interval by a cardiologist was required, with Fridericia correction applied to determine QTc (ie, QTcF).
* Active or clinically significant cardiac disease including any of the following:

  * Unstable angina (eg, anginal symptoms at rest) or onset of angina within 3 months prior to initiating study treatment
  * Myocardial infarction within 6 months prior to initiating study treatment
  * Cardiac arrhythmias currently requiring anti-arrhythmic therapy other than beta blockers
* Any documented history of clinically significant thrombotic, embolic, venous, or arterial events, such as cerebrovascular accident, transient ischemic attack, deep vein thrombosis, or pulmonary embolism necessitating therapeutic anticoagulation within 6 months prior to initiating study treatment (Note: Patients with a tumor-associated thrombus of locally-involved vessels were not excluded from participating in the study.)
* Active infection requiring treatment or chronic infection requiring suppressive therapy
* Chronic or active hepatitis B or C infection requiring treatment with antiviral therapy
* Pleural effusion or ascites that caused respiratory compromise (eg, ≥ grade 2 dyspnea)
* Required ongoing treatment with other drugs thought to potentially have adverse interactions with either of the medications included in the study treatment; if such medications have been used, patients must have discontinued these agents at least 1 week prior to initiating study treatment. Examples include:

  * Strong CYP3A4 inhibitors and/or strong CYP3A4 inducers; the reference list of CYP isozymes and classification of strong, moderate, and weak interactions are available through the Food and Drug Administration (FDA website.
  * Strong inhibitors of P-glycoprotein (P-gp) and/or breast cancer resistance protein (BCRP); the reference list of strong inhibitors of P-gp and BCRP.
  * Simvastatin and other HMG-CoA reductase inhibitors (ie, statins)
  * Drugs that raise gastric pH including proton pump inhibitors and H2-blockers (Note: Short-acting antacids, in place of PPIs and H2-blockers, are permitted.)
  * HDAC inhibitors
* Pregnancy or breastfeeding
* Medical, psychological, or social condition that, in the opinion of the investigator, may have increased the patient's risk or limit the patient's adherence with study requirement