Extended Drug Exposure Research Articles

Testing Mitochondrial-Targeted Drugs in iPSC-RPE from Patients with Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly. No universally effective treatments exist for atrophic or “dry” AMD, which results from loss of the retinal pigment epithelium (RPE) and photoreceptors and accounts for ≈80% of all AMD patients. Prior studies provide evidence for the involvement of mitochondrial dysfunction in AMD pathology. This study used induced pluripotent stem cell (iPSC) RPE derived from five AMD patients to test the efficacy of three drugs (AICAR (5-Aminoimidazole-4-carboxamide ribonucleotide), Metformin, trehalose) that target key processes in maintaining optimal mitochondrial function. The patient iPSC-RPE lines were used in a proof-of-concept drug screen, utilizing an analysis of RPE mitochondrial function following acute and extended drug exposure. Results show considerable variability in drug response across patient cell lines, supporting the need for a personalized medicine approach for treating AMD. Furthermore, our results demonstrate the feasibility of using iPSC-RPE from AMD patients to develop a personalized drug treatment regime and provide a roadmap for the future clinical management of AMD.

From clinical trials to clinical practice: How long are drugs tested and then used by patients?

ObjectiveEvidence is scarce regarding the safety of long-term drug use, especially for drugs treating chronic diseases. To bridge this knowledge gap, this research investigated the differences in drug exposure between clinical trials and clinical practice.Materials and MethodsWe extracted drug follow-up times from clinical trials in ClinicalTrials.gov and compared the difference between clinical trials and real-world usage data for 914 drugs taken by 96 645 927 patients.ResultsA total of 17.5% of drugs had longer median exposure in practice than in trials, 6% of patients had extended exposure to at least 1 drug, and drugs treating nervous system disorders and cardiovascular diseases were the most common among drugs with high rates of extended exposure.ConclusionsFor most of patients, the drug use length is shorter than the tested length in clinical trials. Still, a remarkable number of patients experienced extended drug exposure, particularly for drugs treating nervous system disorders or cardiovascular disorders.

Functionalized polymeric patch for localized oxaliplatin delivery to treat gastric cancer

Localized delivery of chemotherapeutic agents allows extended drug exposure at the target site, thereby reducing systemic toxicity. We report the development of functionalized polymeric patch with unidirectional drug release to treat gastric cancer. The oxaliplatin-loaded patch was prepared by incorporating sodium carboxymethyl cellulose, hydroxypropyl cellulose and polyvinylpyrrolidone. The patch was functionalized by coating with transferrin-poly(lactic-co-glycolic acid) conjugate on one side of the patch for cancer targeting. The other side of the patch was coated with ethylcellulose (EC) to restrict the release of oxaliplatin. The physical and mechanical properties of oxaliplatin-loaded patches were characterized. Mucoadhesion studies using excised rat stomach tissue have shown that the functionalized side of the patch has significantly (p < 0.05) greater mucoadhesion strength compared with EC coated side of the patch. The in vitro and ex vivo (stomach sac and open-membrane model) studies revealed greater permeation of oxaliplatin across the stomach tissue when adhered to the functionalized and non-functionalized side of the patch compared with EC coated side. It was found that the growth inhibition with oxaliplatin solution was not significantly greater compared with corresponding concentrations of oxaliplatin-loaded patch in AGS and Caco-2 cell models. The in vivo studies were performed in mice, where indocyanine green-loaded patch encapsulated in a gelatin capsule was orally administered. The near-infrared (NIR) optical imaging revealed adherence of the patch on the mucosal side of the stomach tissue for up to 6 h. In conclusion, the functionalized polymeric patch loaded with oxaliplatin can be a potential localized delivery system to target gastric cancer.

Analysis of contractile functions of human iPS-derived cardiomyocytes using motion field imaging

Although the cardiotoxicity of anti-cancer drugs is an important issue, the underlying mechanisms remain unknown. To develop a sensitive assay system for cardiotoxicity, we examined effects of anticancer drugs on contractile functions of human iPS cell-derived cardiomyocytes by using non-invasive motion field imaging analysis with extended drug exposure time. We succeeded in continuously measuring stable contractile function. The continued exposure revealed that the difference in cardiotoxicity between cardiotoxic doxorubicin and less toxic erlotinib was more evident after 8 days of treatment than with 3 days of treatment, suggesting that continued exposure improved the predictive power for cardiotoxicity of anti-cancer drugs.

Safety and pharmacokinetics of bimagrumab in healthy older and obese adults with body composition changes in the older cohort.

BackgroundBimagrumab prevents activity of myostatin and other negative regulators of skeletal muscle mass. This randomized double‐blind, placebo‐controlled study investigated safety, pharmacokinetics (PK), and pharmacodynamics of bimagrumab in healthy older and obese adults.MethodsA cohort of older adults (aged 70–85 years) received single intravenous infusions of bimagrumab 30 mg/kg (n = 6) or 3 mg/kg (n = 6) or placebo (n = 4) and was followed for 20 weeks. A second cohort of obese participants [body mass index (BMI) 30–45 kg/m2, aged 18–65 years] received a single intravenous infusion of bimagrumab 30 mg/kg (n = 6) or placebo (n = 2) and was followed for 12 weeks. Outcomes included the safety, tolerability, and PK of bimagrumab, in both cohorts. Measures of pharmacodynamics were performed in the older adult cohort to evaluate the effects of bimagrumab on thigh muscle volume (TMV), total lean body mass (LBM), total fat body mass, and muscle strength.ResultsAll 24 randomized participants completed the study. The older adults had a mean (±SD) age of 74.5 ± 3.4 years and BMI of 26.5 ± 3.5 kg/m2. The obese participants had a mean (±SD) age of 40.4 ± 11.8 years, weight of 98.0 ± 11.3 kg, and BMI of 34.3 ± 3.9 kg/m2. Adverse events in both cohorts were mostly mild. In older adults, most commonly reported adverse events were upper respiratory tract infection, rash, and diarrhoea (each 3/16, 19%). Obese participants reported muscle spasms and rash (both 5/8, 63%) most often. Non‐linearity was observed in the PK concentration profiles of both cohorts due to target‐mediated drug disposition. Bimagrumab 3 and 30 mg/kg increased mean (±SD) TMV (Week 4: 5.3 ± 1.8% and 6.1 ± 2.2%, vs. placebo: 0.5 ± 2.1%, both P ≤ 0.02) and LBM (Week 4: 6.0 ± 3.2%, P = 0.03 and 2.4 ± 2.2%, vs. placebo: 0.1 ± 2.4%), which were maintained longer with higher dose level, while total fat body mass (Week 4: −2.7 ± 2.9% and −1.6 ± 3.0%, vs. placebo: −2.3 ± 3.2%) decreased from baseline in older adults, with no change in muscle strength.ConclusionsBimagrumab was safe and well tolerated and demonstrated similar PK in older and obese adults. A single dose of bimagrumab rapidly increased TMV and LBM and decreased body adiposity in older adults. Muscle hypertrophy and fat loss were sustained with extended drug exposure.

A polymeric paste-drug formulation for local treatment of upper tract urothelial carcinoma

BackgroundIntravesical instillation of chemo- or immunotherapy is commonly used in bladder cancer. Upper tract urothelial carcinoma (UTUC) shares similar pathological features, but current formulations are not suitable for direct instillation to the upper urinary tract. ObjectiveTo evaluate in vivo applicability, characteristics and toxicity of ST-UC, a mucoadhesive polymeric paste formulation of gemcitabine, for upper urinary tract instillation. Material and methodsThree pigs received 10 ml of ST-UC (100 mg/ml gemcitabine) retrogradely into 1 renal pelvis for pharmacokinetic studies. Four days later, a second injection into the contralateral renal pelvis was followed by serial euthanasia of the pigs and nephroureterectomy after 1, 3, and 6 hours. Adverse effects were monitored. Urine, serum, and tissue gemcitabine concentrations were measured, along with histologic examination of the upper urinary tract. ResultsRetrograde instillation of ST-UC was well tolerated with mild, completely receding hydronephrosis. Urine gemcitabine concentrations were highest in the first 3-hour collection interval. Hundred percent of gemcitabine was recovered in the urine within 24 hours. Serum peak concentrations (cmax) of gemcitabine were low at 5.5 µg/ml compared to the 10 to 30 µg/ml levels observed after a single intravenous dose of 1,000 mg/m2 gemcitabine. The formulation was still traceable after one hour and gemcitabine tissue concentrations are supportive of this extended drug exposure. No major histopathological changes were observed. The main limitation of this study is the lack of antitumor activity data. ConclusionThis preclinical evaluation of ST-UC demonstrated feasible instillation in the renal pelvis, no significant safety concerns, and sustained release of gemcitabine.

Ultrasound-triggered therapeutic microbubbles enhance the efficacy of cytotoxic drugs by increasing circulation and tumor drug accumulation and limiting bioavailability and toxicity in normal tissues.

Most cancer patients receive chemotherapy at some stage of their treatment which makes improving the efficacy of cytotoxic drugs an ongoing and important goal. Despite large numbers of potent anti-cancer agents being developed, a major obstacle to clinical translation remains the inability to deliver therapeutic doses to a tumor without causing intolerable side effects. To address this problem, there has been intense interest in nanoformulations and targeted delivery to improve cancer outcomes. The aim of this work was to demonstrate how vascular endothelial growth factor receptor 2 (VEGFR2)-targeted, ultrasound-triggered delivery with therapeutic microbubbles (thMBs) could improve the therapeutic range of cytotoxic drugs.Methods: Using a microfluidic microbubble production platform, we generated thMBs comprising VEGFR2-targeted microbubbles with attached liposomal payloads for localised ultrasound-triggered delivery of irinotecan and SN38 in mouse models of colorectal cancer. Intravenous injection into tumor-bearing mice was used to examine targeting efficiency and tumor pharmacodynamics. High-frequency ultrasound and bioluminescent imaging were used to visualise microbubbles in real-time. Tandem mass spectrometry (LC-MS/MS) was used to quantitate intratumoral drug delivery and tissue biodistribution. Finally, 89Zr PET radiotracing was used to compare biodistribution and tumor accumulation of ultrasound-triggered SN38 thMBs with VEGFR2-targeted SN38 liposomes alone.Results: ThMBs specifically bound VEGFR2 in vitro and significantly improved tumor responses to low dose irinotecan and SN38 in human colorectal cancer xenografts. An ultrasound trigger was essential to achieve the selective effects of thMBs as without it, thMBs failed to extend intratumoral drug delivery or demonstrate enhanced tumor responses. Sensitive LC-MS/MS quantification of drugs and their metabolites demonstrated that thMBs extended drug exposure in tumors but limited exposure in healthy tissues, not exposed to ultrasound, by persistent encapsulation of drug prior to elimination. 89Zr PET radiotracing showed that the percentage injected dose in tumors achieved with thMBs was twice that of VEGFR2-targeted SN38 liposomes alone.Conclusions: thMBs provide a generic platform for the targeted, ultrasound-triggered delivery of cytotoxic drugs by enhancing tumor responses to low dose drug delivery via combined effects on circulation, tumor drug accumulation and exposure and altered metabolism in normal tissues.

1380. Safety of Repurposed Drugs for Multidrug-Resistant and Extensively Drug-Resistant Tuberculosis: An Analysis of Adverse Events Reported in the Literature

BackgroundMulti and extensively drug-resistant (MDR and XDR) tuberculosis (TB) remains a treatment challenge due to drug adverse events (AEs) and long regimens. Our aim was to identify AEs which resulted from repurposing drugs for MDR and XDR-TB.MethodsA PubMed search for case reports of repurposed drugs for MDR and XDR-TB from January 1, 2014 to October 23, 2018 identified 130 patients (78 MDR, 52 XDR) in 91 articles. There were 31 extrapulmonary, 81 pulmonary TB cases, and 18 with both. Drugs were regarded as repurposed if they were either not approved for TB by the FDA, or they were approved for TB but were used in novel populations, novel combinations, or nonstandard doses. Drug labels were reviewed for AEs.ResultsLinezolid (n = 65) and moxifloxacin (n = 48) were the most commonly repurposed drugs. The following were also frequently used: clofazimine (n = 47), levofloxacin (n = 45), amikacin (n = 43), amoxicillin-clavulanate (n = 40), kanamycin (n = 36), carbapenems (n = 22), and clarithromycin (n = 17). Of the drugs that are approved for TB, the following were repurposed in a novel population, dose, or combination: cycloserine (n = 20), bedaquiline (n = 13), capreomycin (n = 4), ethambutol (n = 3), and isoniazid (n = 3). Treatments were discontinued due to AEs in 41 patients. There were no discontinuations for amoxicillin-clavulanate and levofloxacin. Extended drug exposure is a unique treatment feature for MDR and XDR-TB, which often requires ~2 years of treatment. Approximately 87% of treatment discontinuations due to AEs occurred after >1 month of exposure. AEs leading to treatment discontinuation after > 6 months of drug exposure were seen in 15 cases, of which 12 were due to linezolid and cycloserine. Peripheral and optic neuropathy was the most common AE reported (linezolid n = 12, cycloserine n = 1). Most AEs were labeled events.ConclusionSeveral antimicrobials are being repurposed to treat MDR and XDR-TB. There were no AEs reported after prolonged use that was not described in drug labels. Physicians should review information in labeling if prescribing drugs in this manner. There is a need for comparative safety data for repurposed drugs assessed through clinical trials.Disclosures All authors: No reported disclosures.

Continued exposure of anti-cancer drugs to human iPS cell-derived cardiomyocytes can unmask their cardiotoxic effects

Although the cardiotoxicity of anti-cancer drugs is an important issue, the underlying mechanisms remain unknown. To develop a sensitive assay system for cardiotoxicity, we examined effects of anti-cancer drugs on contractile functions of human iPS cell-derived cardiomyocytes by using non-invasive motion field imaging analysis with extended drug exposure time. We succeeded in continuously measuring stable contractile function. The continued exposure revealed that the difference in cardiotoxicity between cardiotoxic doxorubicin and less toxic erlotinib was more evident after 8 days of treatment than with 3 days of treatment, suggesting that continued exposure improved the predictive power for cardiotoxicity of anti-cancer drugs.

Spontaneous dormancy protects Trypanosoma cruzi during extended drug exposure.

The ability of the Chagas disease agent Trypanosoma cruzi to resist extended in vivo exposure to highly effective trypanocidal compounds prompted us to explore the potential for dormancy and its contribution to failed drug treatments in this infection. We document the development of non-proliferating intracellular amastigotes in vivo and in vitro in the absence of drug treatment. Non-proliferative amastigotes ultimately converted to trypomastigotes and established infections in new host cells. Most significantly, dormant amastigotes were uniquely resistant to extended drug treatment in vivo and in vitro and could re-establish a flourishing infection after as many as 30 days of drug exposure. These results demonstrate a dormancy state in T. cruzi that accounts for the failure of highly cytotoxic compounds to completely resolve the infection. The ability of T. cruzi to establish dormancy throws into question current methods for identifying curative drugs but also suggests alternative therapeutic approaches.

Abstract C54: Combination of PARP inhibitor talazoparib with etirinotecan pegol exhibits synergistic anti-tumor effect in non-BRCA preclinical cancer models

Abstract Introduction: Talazoparib (BMN 673) is a highly potent and specific PARP1/2 inhibitor (PARPi) that has demonstrated significant clinical activity in patients with germline BRCA mutation ovarian and breast cancer, as well as in patients with small cell lung cancer. Non-clinically, combination of PARPi, including talazoparib, with Topoisomerase 1 (Top1) inhibitors, such as irinotecan, has shown synergy in BRCA1 mutant MX-1 model (Shen et al. 2013; Hoch et al., NCI-AACR-EORTC 2014). Etirinotecan pegol (NKTR-102, pegylated irinotecan) is a long-acting Top1 inhibitor, designed to provide extended drug exposure to the tumor. In preclinical models, NKTR-102 has improved efficacy and tolerability over irinotecan. We therefore hypothesized that the combination of talazoparib with NKTR-102 would be well tolerated and harness the full synergistic potential of combined Top1 and PARP inhibition. Method: In tolerability studies, three dose levels of talazoparib (0.1, 0.2 and 0.3 mg/kg, QDx14) given with NKTR-102 (10 and 50 mg/kg irinotecan-equivalent dose, iv. Q7Dx2), or irinotecan (10, 30 and 60 mg/kg, ip, Q7Dx2) were evaluated in non-tumor-bearing nude mice (Balb/c, n = 4 per group). In efficacy studies, multiple dose levels of a single agent (i.e., talazoparib, NKTR-102, or irinotecan) as well as corresponding dose combinations were evaluated in NCI-H1048 and HT-29 xenograft tumors with wildtype BRCA status (n = 8-10 per group). Tumor volume and body weight were measured twice weekly. Results: For talazoparib and NKTR-102, all combination doses were tolerated, the maximum mean body weight loss reached 6.2% in the high dose group (0.3 mg/kg talazoparib plus 50 mg/kg NKTR-102). For talazoparib and irinotecan, MTD was observed at 0.2 mg/kg BMN 673 plus 30 mg/kg irinotecan. In efficacy studies, single-agent NKTR-102 had dose-dependent anti-tumor activity against NCI-H1048 tumor, while talazoparib showed limited activity with QDx14 dosing schedule. Combination of talazoparib (0.2 or 0.3 mg/kg, QDx14) with NKTR-102 (10 mg/kg, Day 1) exhibited significantly greater anti-tumor effect than either single agent alone. In contrast, combination of talazoparib (0.2 mg/kg, QDx14) with irinotecan (30 mg/kg, Day 1) only had moderate combination effect in the NCI-H1048 model. In HT-29 model, additive anti-tumor effect was also observed for talazoparib + NKTR-102, but not for talazoparib + irinotecan under the same experimental condition. Conclusion: Our data indicate that the combination of NKTR-102 and talazoparib is better tolerated than that of irinotecan and talazoparib, and results in stronger combination anti-tumor activity. The results support potential development of the combination in human studies. Citation Format: Ying Feng, Yuqiao (Jerry) Shen, Leonard E. Post, Steve Doberstein, Deborah Charych, Ute Hoch. Combination of PARP inhibitor talazoparib with etirinotecan pegol exhibits synergistic anti-tumor effect in non-BRCA preclinical cancer models. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C54.

Abstract 4409: STA-12-8666: a first-in-class HSP90 inhibitor drug conjugate (HDC) designed to selectively deliver chemotherapy to tumors

Abstract Chemotherapeutic drugs have been a mainstay of cancer therapy for decades; however, their effectiveness is often hampered by inefficient drug exposures and undesirable toxicity to normal tissues. Here we report on a novel drug delivery system, termed heat shock protein 90 (HSP90) inhibitor-drug conjugates (HDC), based on the property that small molecule inhibitors of HSP90 are preferentially retained in tumors cells in contrast to their rapid clearance from the circulation and normal tissues. By attaching chemotherapeutic drugs to HSP90 inhibitor backbones, HDC technology exploits this inherent retention property to efficiently deliver cytotoxic payloads directly into tumor tissues and provide extended drug exposure. STA-12-8666 is an HDC that comprises an HSP90 inhibitor fused to the topoisomerase inhibitor SN-38 (active metabolite of irinotecan). In vivo modeling showed that the HSP90 inhibitor moiety was required for tumor-selective retention of STA-12-8666. Prolonged exposure of STA-12-8666 provided extended release of active SN-38 within the tumor compartment, generating up to two weeks of biomarker engagement (γ-H2AX) in contrast to 3-4 days with irinotecan. The broad therapeutic window exhibited by STA-12-8666 conferred superior efficacy and durability over irinotecan treatment alone - resulting in complete or near complete responses (CR) across a broad spectrum of solid tumor models, including an irinotecan-insensitive bladder cancer model and an aggressive lung cancer model where biweekly treatment of STA-12-8666 was initiated at a starting tumor volume 5-times greater that of typical studies. CRs were also observed in a human pancreatic PDX model following 3 doses of STA-12-8666, which were maintained for more than a month. Of note, recurrent PDX tumors remained sensitive to subsequent therapeutic challenge with STA-12-8666 suggesting HDC delivery may circumvent common mechanisms of resistance to irinotecan. Preliminary findings from an ongoing Phase 1 dose escalation study in dogs with spontaneous tumors suggest a well-managed safety profile and encouraging tumor responses. Overall, STA-12-8666 is a promising investigational agent prototypical of a platform technology that can be applied to other cytotoxic payloads to improve therapeutic indices as well as generating new pharmaceutical entities for evaluation as novel anticancer drugs. Citation Format: David A. Proia, Donald L. Smith, Junyi Zhang, Dan Zhou, John-Paul Jimenez, Jim Sang, Sarah Rippy, Cheryl London, Luisa S. Ogawa, Jun Jiang, Teresa Przewloka, Manuel Sequeira, Jaime Acquaviva, Suqin He, John Chu, Chaohua Zhang, Yuan Liu, Josephine Ye, Vladimir Khazak, Igor Astsaturov, Takayo Inoue, Noriaki Tatsuta, Richard C. Bates, Andrew Sonderfan, Dinesh Chimmanamada, Weiwen Ying. STA-12-8666: a first-in-class HSP90 inhibitor drug conjugate (HDC) designed to selectively deliver chemotherapy to tumors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4409. doi:10.1158/1538-7445.AM2015-4409

Vascular normalization in orthotopic glioblastoma following intravenous treatment with lipid-based nanoparticulate formulations of irinotecan (Irinophore C™), doxorubicin (Caelyx®) or vincristine

BackgroundChemotherapy for glioblastoma (GBM) patients is compromised in part by poor perfusion in the tumor. The present study evaluates how treatment with liposomal formulation of irinotecan (Irinophore C™), and other liposomal anticancer drugs, influence the tumor vasculature of GBM models grown either orthotopically or subcutaneously.MethodsLiposomal vincristine (2 mg/kg), doxorubicin (Caelyx®; 15 mg/kg) and irinotecan (Irinophore C™; 25 mg/kg) were injected intravenously (i.v.; once weekly for 3 weeks) in Rag2M mice bearing U251MG tumors. Tumor blood vessel function was assessed using the marker Hoechst 33342 and by magnetic resonance imaging-measured changes in vascular permeability/flow (Ktrans). Changes in CD31 staining density, basement membrane integrity, pericyte coverage, blood vessel diameter were also assessed.ResultsThe three liposomal drugs inhibited tumor growth significantly compared to untreated control (p < 0.05-0.001). The effects on the tumor vasculature were determined 7 days following the last drug dose. There was a 2-3 fold increase in the delivery of Hoechst 33342 observed in subcutaneous tumors (p < 0.001). In contrast there was a 5-10 fold lower level of Hoechst 33342 delivery in the orthotopic model (p < 0.01), with the greatest effect observed following treatment with Irinophore C. Following treatment with Irinophore C, there was a significant reduction in Ktrans in the orthotopic tumors (p < 0.05).ConclusionThe results are consistent with a partial restoration of the blood-brain barrier following treatment. Further, treatment with the selected liposomal drugs gave rise to blood vessels that were morphologically more mature and a vascular network that was more evenly distributed. Taken together the results suggest that treatment can lead to normalization of GBM blood vessel the structure and function. An in vitro assay designed to assess the effects of extended drug exposure on endothelial cells showed that selective cytotoxic activity against proliferating endothelial cells could explain the effects of liposomal formulations on the angiogenic tumor vasculature.

Chitosan–phospholipid blend for sustained and localized delivery of docetaxel to the peritoneal cavity

Localized and sustained delivery of chemotherapeutics presents a “magic bullet” effect by providing high drug concentrations at the target site, extended drug exposure and reduced systemic toxicity. In the present study, an injectable chitosan–phospholipid (PoLi gel) blend is put forth as a strategy to achieve sustained and localized delivery of docetaxel (DTX) following intraperitoneal (IP) administration. The stability of the blend was confirmed in vitro, by turbidity measurements and attributed to specific molecular interactions and the organization of the materials within the blend, as evidenced by FTIR analysis and confocal laser scanning microscopy, respectively. The chitosan and phospholipid were found to colocalize in regions surrounding a mean object area of 11.2 μm 2 with colocalization coefficients of 43% and 46% for the chitosan and phospholipid, respectively. The PoLi gel blend afforded sustained drug release as seen both in vitro (2.4 ± 0.7% DTX per day) and in vivo (4.4 ± 0.7% DTX per day). Constant concentrations of DTX were observed over a 2-week period in plasma and relevant peritoneal tissues, with no signs of toxicity or inflammation, following IP administration of the blend in healthy CD-1 mice. At DTX doses of 28.8 and 19.2 mg/kg, the blend showed significant tumor inhibition of 87.3 ± 9.3% and 74.1 ± 25.9%, respectively, in a murine xenograft model of human ovarian adenocarcinoma. This localized delivery system has shown excellent potential for sustained IP treatment of cancers, such as ovarian, that reside in the peritoneal cavity.

Phase I and Pharmacokinetic Study of Pegylated Liposomal CKD-602 in Patients with Advanced Malignancies

S-CKD602 is a pegylated liposomal formulation of CKD602, a semisynthetic camptothecin analogue. Pegylated (STEALTH) liposomes can achieve extended drug exposure in plasma and tumor. Based on promising preclinical data, the first phase I study of S-CKD602 was done in patients with refractory solid tumors. S-CKD602 was administered i.v. every 3 weeks. Modified Fibonacci escalation was used (three to six patients/cohort), and dose levels ranged from 0.1 to 2.5 mg/m2. Serial plasma samples were obtained over 2 weeks and total (lactone+hydroxyl acid) concentrations of encapsulated, released, and sum total (encapsulated+released) CKD602 measured by liquid chromatography-tandem mass spectrometry. Forty-five patients (21 males) were treated. Median age, 62 years (range, 33-79 years) and Eastern Cooperative Oncology Group status, 0 to 1 (43 patients) and 2 (2 patients). Dose-limiting toxicities of grade 3 mucositis occurred in one of six patients at 0.3 mg/m2, grade 3 and 4 bone marrow suppression in two of three patients at 2.5 mg/m2, and grade 3 febrile neutropenia and anemia in one of six patients at 2.1 mg/m2. The maximum tolerated dose was 2.1 mg/m2. Partial responses occurred in two patients with refractory ovarian cancer (1.7 and 2.1 mg/m2). High interpatient variability occurred in the pharmacokinetic disposition of encapsulated and released CKD602. S-CKD602 represents a promising new liposomal camptothecin analogue with manageable toxicity and promising antitumor activity. Phase II studies of S-CKD602 at 2.1 mg/m2 i.v. once every 3 weeks are planned. Prolonged plasma exposure over 1 to 2 weeks is consistent with STEALTH liposomes and provides extended exposure compared with single doses of nonliposomal camptothecins.

Age and body composition related-effects on the pharmacokinetic disposition of STEALTH liposomal CKD- 602 (S-CKD602) in patients with advanced solid tumors

2528 Background: STEALTH liposomes (SL), which contain lipids conjugated to polyethylene glycol (PEG), prolong the circulation time of a drug in plasma, achieve high and extended drug exposure in tumor, and are eliminated via the reticuloendothelial system (RES). S- CKD602 is a SL formulation of CKD-602, a camptothecin analogue. CKD-602 released from S-CKD602 is eliminated by the kidney. There is significant interpatient variability in the pharmacokinetic (PK) disposition of S-CKD602. Thus, there is a need to identify factors associated with the PK variability. We hypothesize that older patients (pts) have a reduced capacity to eliminate SL agents due to age-related impairment of the RES and that body composition alters the disposition of SL. Methods: PK studies of S-CKD602 were performed in a phase I study of S-CKD602 at 0.1 to 2.5 mg/m2 IV q 21 d in pts with solid tumors. Concentrations of encapsulated (E), released (R), and sum total (E + R) CKD-602 in plasma and CKD-602 in urine were measured by LC-MS/MS. Area under the plasma concentration versus time curve (AUC) was calculated and normalized by dose (AUC/dose). The ratio of total body weight to ideal body weight (TBW/IBW) was calculated as a measure of body composition. Results: Mean ± SD S-CKD602 sum total AUC/dose in pts &lt; 60 (n = 13) and = 60 (n = 17) years of age (yo) were 4.5 ± 5.0 and 11.2 ± 11.0 (μg/ml·h)/(mg/m2), respectively (P&lt;0.05). Controlling for age, there was a statistically significant inverse relationship between TBW/IBW and S-CKD602 AUC/dose where low TBW/IBW was associated with high AUC/dose in both age groups (P&lt;0.05). The cumulative amount of CKD-602 recovered in the urine was 2.2-fold higher in pts &lt; 60 yo compared with = 60 yo. Conclusions: These data suggest that pts = 60 yo have a reduced clearance of S-CKD602 and reduced release of CKD-602 from S- CKD602 compared with pts &lt; 60 yo. In addition, pts &lt; 60 and = 60 yo with a lean body composition may have a reduced tissue distribution and an increased plasma exposure of S-CKD602. The clinical significance of these differences and the factors associated with them need to be evaluated for S-CKD602 and other liposomal and nanoparticle anticancer agents. No significant financial relationships to disclose.

Final results of a phase I and pharmacokinetic study of STEALTH liposomal CKD-602 (S-CKD602) in patients with advanced solid tumors

2013 Background: S-CKD602 is a pegylated STEALTH liposomal formulation of CKD-602, a semi-synthetic analogue of camptothecin (CPT) and topoisomerase I inhibitor. Preclinical studies have shown that prolonged exposure to CPT achieves the greatest antitumor activity. STEALTH liposomes prolong the circulation time in plasma, achieve high and extended drug exposure in tumor, and provide a convenient dosing schedule. Methods: Patients (pts) were administered S-CKD602 IV over 1 h once every 3 wks. Modified Fibonacci escalation was used (3–6 pts/cohort), and dose levels ranged from 0.1–2.5 mg/m2. Serial plasma samples were obtained prior to administration to 96 h after administration, and on days 8 and 15 of cycle 1. Plasma samples were processed to measure concentrations of encapsulated (E), released (R), and sum total (E+R) CKD602 total (lactone + hydroxyl acid) by LC-MS/MS. Area under the plasma conc versus time curve (AUC0-∞) and t1/2 were estimated. Results: 45 pts (21 male) have been treated: median age 62 y (range: 33–79 y); ECOG status: 0 and 1 (43 pts), 2 (2 pts). The majority of reported adverse events were grade (G) 1 and 2. Frequent nonhematological toxicities were asthenia, nausea, diarrhea, vomiting, and anorexia. Dose-limiting toxicities of G3 mucositis occurred in 1/6 pts at 0.3 mg/m2, G3/4 bone marrow suppression in 2/3 pts at 2.5 mg/m2, and G3 febrile neutropenia in 1/6 pts at 2.1 mg/m2. The maximum tolerated dose was 2.1 mg/m2. Stable disease for ≥ 6 cycles occurred in 5 pts (hepatocellular carcinoma (CA), thyroid, prostate, 2 pts sarcoma). Partial responses occurred in 2 pts with ovarian CA (1.7 and 2.1 mg/m2). At 2.1 mg/m2, the mean ± SD AUC and t1/2 of sum total S-CKD602 were 44 ± 33 μg/mL·h and 18 ± 8 h, respectively. In all plasma samples, &gt;90% of drug was encapsulated. Conclusions: S-CKD602 represents a promising new STEALTH liposomal CPT agent with manageable toxicity and promising antitumor activity. Phase II studies of S-CKD602 at 2.1 mg/m2 IV once every 3 wks are planned. Prolonged plasma exposure over 1 to 2 wks is consistent with STEALTH liposomes and provides extended exposure compared with non-liposomal CPT. (Supported by ALZA and NIH/NCCR/GCRC #5M01 RR 00056). [Table: see text]

Novel tricyclic-alpha-alkyloxyphenylpropionic acids: dual PPARalpha/gamma agonists with hypolipidemic and antidiabetic activity.

Synthesis and structure-activity relationships of tricyclic alpha-ethoxy-phenylpropionic acid derivatives guided by in vitro PPARalpha and PPARgamma transactivation data and computer modeling led to the identification of the novel carbazole analogue, 3q, with dual PPARalpha (EC(50) = 0.36 microM) and PPARgamma (EC(50) = 0.17 microM) activity in vitro. Ten days treatment of db/db mice with 3q improved the insulin sensitivity, as measured by OGTT, better than that seen with both pioglitazone and rosiglitazone treatment, suggesting in vivo PPARgamma activity. Likewise, 3q lowered plasma triglycerides and cholesterol in high cholesterol fed rats after 4 days treatment, indicating in vivo PPARalpha activity. Investigations of the pharmacokinetics of selected compounds suggested that extended drug exposure improved the in vivo activity of in vitro active compounds.