Pharmacokinetic and safety study of subcutaneously administered weekly ING-1, a human engineere monoclonal antibody targeting human EpCAM, in patients with advanced solid tumors

BACKGROUND

ING-1 is a high-affinity, human engineeredtrade mark monoclonal antibody that recognizes a 40 kilodalton epithelial cell adhesion molecule (EpCAM) glycoprotein that is expressed in high levels on most adenocarcinomas and is an attractive target for immunotherapy.

METHODS

ING-1 was administered subcutaneously weekly at doses between 0.1 and 2 mg/kg/week. Pharmacokinetic samples were drawn during weeks 1 and 6.

RESULTS

Fourteen patients with advanced refractory cancer received a median of 6 (range 1-9) doses of ING-1. At 1 mg/kg, a 62-year-old man with colon cancer developed reversible grade 3 pancreatitis after the third dose. His plasma ING-1 levels were similar to the other two patients dosed at 1 mg/kg. Two patients dosed at 0.6 mg/kg experienced stable disease at 6 weeks. Peak drug levels increased with dose and time, suggesting drug accumulation with repeated dosing. Low human anti-human antibody response was noted in three of the 13 patients assessed and was directed towards the variable region of ING-1.

CONCLUSIONS

Weekly ING-1 administered subcutaneously was well tolerated at 0.6 mg/kg/week and further experience at this dose is warranted to demonstrate safety. The risk of pancreatitis and the marginal anti-tumor effect may preclude further monotherapy studies; however, combination studies with chemotherapy are warranted.

A phase I study of intravenous tetra-O-methyl nordihydroguaiaretic acid in patients with refractory malignancy

3584

Background: Tetra-o-methyl nordihydroguaiaretic acid (terameprocol-also EM-1421 or M4N) is a semi-synthetic derivative of a naturally occurring plant lignan. Terameprocol blocks cell cycle progression by inhibiting expression of the Sp1-dependent cdk1 gene and promotes apoptosis by inhibiting survivin. Methods: A dose escalation, open-label study enrolled patients (pt) with malignancies refractory to surgery, radiation therapy, and/or chemotherapy. Terameprocol was administered daily by intravenous infusion for 5 days (d) every 28 d over 30 minutes, with dose escalation (100, 200, 375, 750, 1,500, 2,200, and 3,300 mg) in cohorts of 3–6 pt. Tumor measurement (CT and PET scans) was performed at baseline and every 2 to 4 cycles. Pt at the 2,200mg and 3,300mg doses had circulating tumor cells (CTC) measured prior to dosing. Pharmacokinetics (PK) was evaluated for the first 2 cycles. Results: Twenty nine pt (17 male), median age 61 years, with gynecological (21%), lung (17%), colorectal (17%), or other cancer (45%) were enrolled. All pt were evaluable for toxicity and 21 pt for efficacy. At the highest dose (3,300 mg/d), dose limiting toxicity (DLT) of metabolic acidosis/respiratory failure considered drug related was observed in 1 of 3 pt, and no additional pt was enrolled at this dose. The next lower dose cohort (2,200 mg/d) was expanded (11 pt) and no DLT has been observed. Best response by RECIST criteria included a partial response in 1 pt and stable disease in 6 pt. Three pt discontinued for reason other than progression, and 11 had progressive disease. Pharmacokinetics demonstrated dose linearity. The volume of distribution was 300–1,000 liters, and the half-life ∼ 20–30 hours. No obvious trend was seen in CTCs. Across all doses, 108 adverse events, with 10 severe events, were observed. Conclusions: Terameprocol is well tolerated up to a dose of 2,200 mg and warrants further evaluation. Expansion continues at this dose level. There is clinical benefit in this refractory population that warrants further investigation.

No significant financial relationships to disclose.

Pharmacodynamic and safety study of reolysin in patients with advanced solid tumors

14004

Background: Reolysin is an intravenous formulation of reovirus serotype 3 - Dearing strain which is a double stranded RNA non-enveloped icosahedral virus capable of inducing cytopathic effects in cancer cells that have an activating mutation in the ras protooncogene. Pre clinical testing has identified cancer cell lines as being susceptible to reovirus infection. Methods: This was an open- label single center phase I safety and dose escalation trial of reolysin administered intravenously over 1 hour on day 0 in a 28 day cycle. Dose escalations were in half log increments. Serum for neutralizing antibody (NA) was drawn at baseline, and days (d) 1, 7, 14, 21, and 28, and serum, stool, saliva, and urine for viral shedding (by RT-PCR) were sampled on d 1,7,14,21, and 28. Response was assessed by imaging studies after 1, 3, 5, and 7 cycles. Results: 18 patients (pt); median age 57 (40–72) years; performance status 0–1; diagnoses - ovarian (6), colorectal (5), and others (7) received 27 cycles of reolysin (median 1, range 1–7) in 6 dose cohorts of 1x108, 3x108, 1x109, 3x109, 1x1010, and 3x1010 tissue culture infective dose (TCID)50. No protocol defined dose limiting toxicities were observed. Drug related grade 2 toxicities included chills (2 pt), and fatigue (3 pt). The only grade 3 event was fever in cycle 7 in a 57 year old woman with progressive breast cancer, treated at a dose of 1x1010 TCID50. She was noted to have 28.5% shrinkage in objective tumor volume. An additional 7 pt had stable disease (SD). No NA was detectable in the serum in any pt at baseline; however all pt developed NA (on d 5 in 5 pt, d 8 in 11 pt, d 14 in 1 pt, and d 28 in 1 pt) during the course of the study. Viral shedding was observed in serum - 5 pt, stool - 3 pt, saliva - 3 pt, and urine - 4 pt. Of interest, 4 of 5 pt with viral shedding had SD as their best response. However, there was no observed relationship between NA formation and SD. Conclusion: Reolysin administered as a one hour infusion on a monthly schedule is safe and well-tolerated even in multiple doses. This preliminary data suggests there is anti-tumor activity of reolysin as a single agent, and warrants further studies either alone or in combination with cytotoxic chemotherapy.

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Peripheral blood mononuclear and tumor cell pharmacodynamics of the novel epothilone B analogue, ixabepilone

BACKGROUND

We previously demonstrated that peak microtubule bundle formation (MBF) in peripheral blood mononuclear cells (PBMCs) occurs at the end of drug infusion and correlates with drug pharmacokinetics (PK). In the current study, a new expanded evaluation of drug target effect was undertaken.

PATIENTS AND METHODS

Patients with advanced solid malignancies were treated with ixabepilone 40 mg/m2 administered as a 1-h i.v. infusion every 3 weeks. Blood, plasma, and tumor tissue sampling was carried out to characterize pharmacodynamics and PK.

RESULTS

Forty-seven patients were treated with 141 cycles of ixabepilone. In both PBMCs (n=27) and tumor cells (n=9), peak MBF occurred at the end of infusion; however, at 24-72 h after drug infusion, the number of cells with MBF was significantly greater in tumor cells, relative to PBMCs. A Hill model (EC50=109.65 ng/ml; r2=0.94) was fitted, which demonstrated a relationship between percentage of PBMCs with MBF and plasma ixabepilone concentration. The percentage of PBMCs with MBF at the end of infusion also correlated with severity of neutropenia (P=0.050).

CONCLUSIONS

Plasma ixabepilone concentration and severity of neutropenia correlate with the level of MBF in PBMCs. Therefore, this technically straightforward assay should be considered as a complement to the clinical development of novel microtubule-binding agents.

The evolving portrait of cancer metastasis

The phenomenon of cancer metastasis remains poorly understood. We discuss here various conceptual frameworks that attempt to rationalize the mechanisms by which tumors acquire metastatic ability. Portrayal of cancer as a somatic Darwinian process occurring within a tissue fails to fully explain the phenomenon of metastatic competence. The biology of pre-neoplastic cells also complicates this picture, since the phenotypes of normal cellular precursors are clearly relevant to metastatic behavior following transformation. Recent experimental results help to shed light on these and other considerations regarding the molecular mechanisms of malignant progression.

Inhibition of drug metabolism by blocking the activation of nuclear receptors by ketoconazole

Individual variation in drug metabolism is a major cause of unpredictable side effects during therapy. Drug metabolism is controlled by a class of orphan nuclear receptors (NRs), which regulate expression of genes such as CYP (cytochrome)3A4 and MDR-1 (multi-drug resistance-1), that are involved in this process. We have found that xenobiotic-mediated induction of CYP3A4 and MDR-1 gene transcription was inhibited by ketoconazole, a commonly used antifungal drug. Ketoconazole mediated its effect by inhibiting the activation of NRs, human pregnenolone X receptor and constitutive androstene receptor, involved in regulation of CYP3A4 and MDR-1. The effect of ketoconazole was specific to the group of NRs that control xenobiotic metabolism. Ketoconazole disrupted the interaction of the xenobiotic receptor PXR with the co-activator steroid receptor co-activator-1. Ketoconazole treatment resulted in delayed metabolism of tribromoethanol anesthetic in mice, which was correlated to the inhibition of PXR activation and downmodulation of cyp3a11 and mdr-1 genes and proteins. These studies demonstrate for the first time that ketoconazole represses the coordinated activation of genes involved in drug metabolism, by blocking activation of a specific subset of NRs. Our results suggest that ketoconazole can be used as a pan-antagonist of NRs involved in xenobiotic metabolism in vivo, which may lead to novel strategies that improve drug effect and tolerance.

First-in-human phase I trial of a novel epothilone, KOS-1584

2003

Background: KOS-1584 (9,10-didehydroepothilone D) was discovered as part of a screening program to develop a new generation of epothilones with higher potency and an improved pharmacologic/pharmacokinetic (PK) profile. Epothilones stabilize microtubule polymerization, inducing rapid G2/M arrest and apoptosis. Antitumor activity of KOS-1584 (Chou et al 2003) is approximately 3–12 fold more potent when compared to the structurally related Epothilone D. KOS-1584 demonstrates enhanced tumor tissue penetration and reduced exposure to selected tissues (including CNS). We report the results of the initial dose-escalation trial in which KOS-1584 was administered to pts with advanced solid malignancies. Methods: Define the MTD, toxicity profile and PK of KOS-1584 when administered via 3-hour infusion every 3 weeks. PK was determined after the 1st and 2nd infusion. Pharmacodynamics were assessed by serial sampling of PBMCs for microtubule bundle formation. Results: 27 pts (17 F; median age 60; median ECOG PS 1; median prior regimens 3, range 0–7) enrolled in 8 dose levels (between 0.8 - 11.3 mg/m2). To date, no Cycle 1 DLT has been seen. Toxicities (n=24) did not show obvious dose dependency; common toxicity (Grade 1–2) included gastrointestinal (diarrhea, constipation, nausea), fatigue, and ↑AST. Drug-related Grade 3 toxicity: constipation, fatigue and ↑AST (1 each). Drug-related neurotoxicity was not notable. PK/parent (n=25): t½ 17.7 ± 4.6h, Vz 741±330 L and CL 30.2± 16.5 L/h. At 8.5 mg/m2 Cmax 78 ± 29 ng/mL; AUCtot 631 ± 337 ng*h/mL. Cmax and AUCtot increased linearly with dose over the range tested. Vz is ∼5-fold and t½ 2-fold higher than that of Epothilone D. Dose dependent increases in microtubule bundle formation were observed (8.5 mg/m2: 40–50% at end of infusion, compared to 60–65% for ixabepilone and 50–60% for Epothilone D using the same assay at their phase 2 dose). A sigmoidal Emax model described the relationship between plasma concentration and microtubule bundle formation. Activity consisted of 4 pts with extended stable disease (6 cycles leiomyosarcoma and ovarian cancer; 5 cycles colon cancer; a 2nd patient with ovarian cancer is active at 5 cycles). Of these, 3 had document progressive disease prior to study. Conclusions: Accrual is continuing in order to define the optimal dose on the 3-week regimen.

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A phase I pharmacokinetic (PK) study of the Epothilone B analogue, ixabepilone (BMS-247550) in patients (pts) with advanced malignancies and varying degrees of hepatic impairment. A SWOG Early Therapeutics Committee and NCI Organ Dysfunction Working Group Trial

2004

Background: Ixabepilone (Ix) is a semisynthetic Epothilone B derivative with antitumor activity in breast cancer pts previously treated with taxanes and in chemotherapy naïve prostate cancer pts. Because Ix is hepatically metabolized, the following study was performed to define dosing recommendations for pts with varying degrees of hepatic impairment. Methods: Pts were classified into hepatic dysfunction cohorts defined by a modified NCI Organ Dysfunction Working Group (NCI) schema. Starting doses were escalated in new pts independently in each cohort using a standard phase I design. Results: Overall, 71 pts were registered and 66 pts are evaluable for cycle 1 dose limiting toxicities (DLTs). Ix was administered at 10–40 mg/m2 as 10 minute infusions q3wks. Dose levels reached 40, 40, 30, and 20 mg/m2 for pts in Groups A, B, C and D, respectively. In group B, DLTs were observed in 2/12 pts treated at 30 mg/m2 (febrile neutropenia, grade (gr)3 mucositis, and gr3 diarrhea) and 3/8 pts at 40 mg/m2 (febrile neutropenia, gr3 nausea/vomiting, gr3 hyponatremia). In group C, DLTs were observed in 2/10 pts at 20 mg/m2 (gr3 dehydration, gr3 muscle weakness) and 2/3 pts at 30 mg/m2 (febrile neutropenia, gr 4 neutropenia). In group D, DLTs were observed in 2/9 pts at 10 mg/m2 (gr3 infection and gr3 renal failure) and 1/5 pts treated at 20 mg/m2 (gr3 infection). Otherwise, Ix was generally well tolerated. Pharmacokinetic parameters are currently being analyzed. No objective responses have been documented. Conclusions: Ix dose reduction is required in pts with moderate to severe liver dysfunction. The recommended Ix dose for group C patients is 30 mg/m2. To define the impact of mild liver impairment, Group B has been stratified further into B1 (Bili ≤ ULN and AST > ULN) and B2 (ULN < Bili ≤ 1.5 × ULN, AST any). Accrual continues to groups B1 and B2 at 40 mg/m2 and group D at 20 mg/m2.

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Effect of ketoconazole on the pharmacokinetics and pharmacodynamics of ixabepilone

2005

Background: Ixabepilone (Ixa) is the first analog in a new class of antineoplastic agents, the epothilones, which stabilizes microtubules and induces apoptosis. Ixa has shown clinical activity in a broad range of tumors. Oxidative metabolism by CYP3A4/5 appears to be a prominent route of Ixa biotransformation in vitro. As a single agent, the recommended dose is 40 mg/m2 over 3 hours once every three weeks. Methods: This was an open-label, sequential study to assess the effect of CYP3A4/5 inhibition on the pharmacokinetics (PK) and pharmacodynamics (PD) of Ixa. Ketoconazole (K) was used as a model inhibitor of CYP3A4/5. Patients were administered a single 10 (n=4), 20 (n=12), 25 (n=7) or 30 (n=4) mg/m2 intravenous (iv) infusion of Ixa with K (400 mg/d orally x 6 days) during cycle 1, and a single 40 mg/m2 iv infusion of Ixa during Cycle 2. Cycles were repeated every 21 days. Detailed PK and PD analysis was performed in cycles 1 and 2. Results: The observed adjusted geometric mean of Ixa AUC for subjects with K was 2892 vs. 1628 ng/mL*hr in subjects without K. The ratio of the geometric means of normalized Ixa AUC and Cmax in Cycle 1/Cycle 2 were 1.78 and 1.07, respectively. The percent of peripheral blood mononuclear cells with tubulin bundle formation after administration of 20 mg/m2 Ixa with K was similar to that observed with single agent Ixa at a dose of 40 mg/ m2. The maximum tolerated dose of Ixa with K was 20 mg/m2. Dose limiting toxicities of Ixa with K were similar to those observed in previous Phase 1 studies of single agent Ixa and included prolonged neutropenia, febrile neutropenia, mucositis, elevated liver function enzymes, and fatigue. Conclusions: Oxidative metabolism by CYP3A4/5 appears to be a clinically important route of Ixa biotransformation. Inhibition of CYP3A4/5 by K affects the Ixa tolerable dose, increases the AUC and results in similar PD effects at half the recommended dose.

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Pharmacokinetic (pk) and safety study of irinotecan (Ir) and capecitabine (Cp) administered on a weekly schedule

2061

Background: In vitro studies show synergy between Cp and Ir. Since both drugs are metabolized by carboxyl esterases (CE), the potential for competitive inhibition is possible. We conducted a study to identify a safe dose and potential drug-drug interactions of this combination. Methods: This was an open-label phase I dose escalation trial. Ir was given as a 30 min infusion on days 1 and 8, and Cp on days 1–14 of a 21 day cycle. Plasma for pk analyses was drawn on days 1 and 8, at 0, 15, 30, 45, 60, 90, 120, 240, 360 min, and 24 hr, for total CPT-11, SN-38, SN-38-glucuronide (G), and APC. Results: 47 patients (pt) - median age 60 (32–83) years; performance status 0–1 (96%); diagnoses- ovarian (10), breast (5), cervical (5), colorectal (10) and others (17) received 202 (median 4, range 1–18) cycles in 6 dose cohorts - Ir (mg/m2)/Cp (mg/m2/day in 2 divided doses) 75/1500, 85/1500, 85/1750, 100/1750, 100/2000, 115/2000. At the highest dose tested (115/2000), 1 of 3 pt developed grade (G) 4 neutropenia with fatal gram-negative sepsis. At dose level 5 (100/2000), 2 of 21 patients developed cycle 1 DLT - G 3 diarrhea/vomiting and G 3 diarrhea. Across all doses and patients, the G 3–4 toxicities observed were diarrhea (12 pt), vomiting (2 pt), fatigue (5 pt), hand-foot syndrome (1 pt), neutropenia (6 pt), anemia (4 pt), thrombocytopenia (2 pt) and elevation of AST/ALT (1 pt). Anti-tumor responses include partial response in 8 of 35 evaluable (23%) pts (3 breast, 4 ovarian, 1 cervical), a minimal response (1 breast), and a 90% decline in PSA (1 pt). Detailed pk analyses show that AUC(0-∞) of Ir, SN-38G, and APC were similar on days 1 and 8. However, SN-38 Tmax was longer on Day 8 (0.87 hr vs. 1.22 hr, p = 0.012). While SN-38 AUC (0-∞) was higher on day 1 by 45%, this was not statistically significant (p = 0.167). Conclusions: Cp results in a delayed conversion of Ir to SN-38, suggesting competitive inhibition of CE at a molecular level without clinical significance. This could portend a drug-drug interaction when Ir is combined with substrates of CE, and warrants further study. The combination of Ir and Cp is safe and well tolerated at 100/2000, and warrants further evaluation in breast, cervical, ovarian and other malignancies.

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Banoxantrone (AQ4N), tissue CYP 450 targeted prodrug: The results of a phase I study using an accelerated dose escalation

2011

Background: AQ4N was rationally designed to have anti-tumor activity following bioreduction by tissue cytochrome P450 to AQ4, an active DNA topoisomerase II inhibitor. Preclinical studies demonstrated AQ4N selectively targets lymphoid tissues and hypoxic tumor tissues. This study assessed the maximum tolerated dose (MTD), pharmacokinetic (PK), and pharmacodynamic (PD) of repeated weekly dosing of AQ4N in patients (pts) with advanced cancers. Methods: AQ4N was administered IV on Days 1, 8, and 15 of a 28-day cycle in the following dose cohorts 12, 24, 48, 96, 192, 384, 768, and 1200 mg/m2. Accelerated titration design 2B was employed and the MTD was defined by ≤ 33% of 6 pts with a drug-related dose limiting toxicity (DLT). Response was assessed every 8 weeks by RECIST. Results: 16 pts were enrolled. A single pt per cohort was treated up to 384 mg/m2. At 1200 mg/m2, 2 of 5 pts experienced a DLT (Grade 5 respiratory distress and Grade 3 fatigue). A total of 5 pts were treated without toxicity at the 768 mg/m2, and established this dose as MTD. One pt in the 1200 mg/m2 cohort died during the trial from acute complications of metastatic soft tissue sarcoma and respiratory distress. The most common adverse events (AE) observed were fatigue (63%), anorexia (38%), nausea (38%), vomiting (38%), peripheral edema (25%), and diarrhea (25%). 6 pts experienced 8 serious AEs. Anticipated blue coloration of skin and body fluids was observed. One pt (48 mg/m2) with renal cancer has had stable disease for > 12 months. The PK was linear over all doses studied. At 768 mg/m2 (n=4), the Day 1 AQ4N Cmax was 99.8 ± 27.0 μg/mL, AUC0-∞ was 259.5 ± 67.8 μg·h/mL, and T1/2 was 3.9 ± 0.7 h (range 3.1–4.8 h). A predictable dose-related and exposure related decrease in lymphocytes and neutrophils were observed. Conclusions: AQ4N is well tolerated when administered on a weekly schedule. AQ4N levels sufficient for anti-neoplastic activity in pre-clinical models are achieved with weekly dosing at 768 mg/m2. AQ4N monotherapy and combination trials with chemo- and radiation therapy are planned.

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Targeting cyclin D1, a downstream effector of INI1/hSNF5, in rhabdoid tumors

Rhabdoid tumors (RTs) are aggressive and currently incurable pediatric malignancies. INI1/hSNF5 is a tumor suppressor biallelically inactivated in RTs. Our previous studies have indicated that cyclin D1 is a key downstream target of INI1/hSNF5 and genesis and/or survival of RTs in vivo is critically dependent on the presence of cyclin D1. In this report, we have tested the hypothesis that therapeutic targeting of cyclin D1 is an effective means of treating RTs. We found that RNA interference of cyclin D1 in rhabdoid cells was sufficient to induce G1 arrest and apoptosis. Furthermore, we found that pharmacological intervention with low micromolar concentrations of N-(4-hydroxyphenyl)retinamide (4-HPR), which downmodulates cyclin D1, induced G1 arrest and apoptosis in rhabdoid cell lines. 4-HPR in combination with 4-hydroxy-tamoxifen (4OH-Tam), synergistically inhibited survival as well as anchorage-dependent and -independent growth of rhabdoid cells and caused synergistic induction of cell cycle arrest and apoptosis. 4-HPR and tamoxifen exhibited synergistic growth inhibition of RTs in xenograft models in vivo. The effects of combination of drugs were correlated to the depletion of cyclin D1 levels both in in vitro and in vivo tumor models. These results demonstrate that 4-HPR and tamoxifen are effective chemotherapeutic agents for RTs. We propose that downmodulation of cyclin D1 is a novel and effective therapeutic strategy for RTs.

Antisense strategies for oncogene inactivation

Antisense oligonucleotides have been evaluated as antineoplastic agents in a series of clinical trials, with mixed results. However, phase III trials incorporating G3139, a phosphorothioate oligomer targeted to the initiation codon region of the bcl-2 mRNA, have recently been completed in advanced melanoma, myeloma, and chronic lymphocytic leukemia (CLL). This article discusses the mechanism of the antisense effect and its dependence on the cellular internalization of oligonucleotides and the activity of RNase H. It also describes the properties, specific and nonspecific, of phosphorothioate oligonucleotides, the predominant species in current clinical trials, and discusses pharmacokinetic data obtained from earlier phase I and II trials employing these molecules. While the application of antisense technology to the treatment of human cancer is conceptually straightforward, in practice there are many complicated, mechanistically based questions that must be considered.