Phase 2 study of idelalisib and entospletinib: pneumonitis limits combination therapy in relapsed refractory CLL and NHL.

Although agents targeting B-cell receptor signaling have provided practice-changing results in relapsed chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma (NHL), they require prolonged administration and provide incomplete responses. Given synergistic preclinical activity with phosphatidylinositol 3-kinase δ and spleen tyrosine kinase inhibition, this phase 2 study evaluated the safety and efficacy of the combination of idelalisib and entospletinib. Eligible patients with relapsed or refractory CLL or NHL underwent intrapatient dose escalation with each agent. With a median treatment exposure of 10 weeks, 60% and 36% of patients with CLL or follicular lymphoma, respectively, achieved objective responses. However, the study was terminated early because of treatment-emergent pneumonitis in 18% of patients (severe in 11 of 12 cases). Although most patients recovered with supportive measures and systemic steroids, 2 fatalities occurred and were attributed to treatment-emergent pneumonitis. Increases of interferon-γ and interleukins 6, 7, and 8 occurred over time in patients who developed pneumonitis. Future studies of novel combinations should employ conservative designs that incorporate pharmacodynamics/biomarker monitoring. These investigations should also prospectively evaluate plasma cytokine/chemokine levels in an attempt to validate biomarkers predictive of response and toxicity. This trial was registered at www.clinicaltrials.gov as #NCT01796470.

Randomized comparison of liposomal amphotericin B versus placebo to prevent invasive mycoses in acute lymphoblastic leukaemia.

Objectives: To prevent invasive fungal disease (IFD) in adult patients undergoing remission-induction chemotherapy for newly diagnosed acute lymphoblastic leukaemia (ALL). Patients and methods: In a double-blind multicentre Phase 3 study, patients received prophylactic liposomal amphotericin B (L-AMB) at 5 mg/kg intravenously or placebo twice weekly in a 2:1 random allocation during remission-induction treatment. The primary endpoint was the development of proven or probable IFD. Secondary endpoints included those focused on the safety and tolerability of prophylactic L-AMB. Results: Three hundred and fifty-five patients from 86 centres in Europe and South America received at least one dose of L-AMB ( n = 237) or placebo ( n = 118). Rates of proven and probable IFD assessed independently were 7.9% (18/228) in the L-AMB group and 11.7% (13/111) in the placebo group ( P = 0.24). Rates of possible IFD were 4.8% (11/228) in the L-AMB and 5.4% (6/111) in the placebo group ( P = 0.82). The remission-induction phase was a median of 22 days for both groups. Overall mortality was similar between the groups: 7.2% (17/237) for L-AMB and 6.8% (8/118) for placebo ( P = 1.00). Hypokalaemia and creatinine increase were significantly more frequent with L-AMB. Conclusions: The IFD rate among adult patients undergoing remission-induction chemotherapy for newly diagnosed ALL was 11.7% in the placebo group, and was not significantly different in patients receiving L-AMB, suggesting that the L-AMB regimen studied is not effective as prophylaxis against IFD. The IFD rate appears higher than previously reported, warranting further investigation. Tolerability of L-AMB was what might be expected. Further studies are needed to determine the optimal antifungal strategy during remission-induction chemotherapy of ALL.

Assessment of GS-9219 in a pet dog model of non-Hodgkin's lymphoma.

PURPOSE: To assess, in dogs with naturally occurring non-Hodgkin's lymphoma, pharmacokinetics, safety, and activity of GS-9219, a prodrug of the nucleotide analogue 9-(2-phosphonylmethoxyethyl) guanine (PMEG), which delivers PMEG and its phosphorylated metabolites to lymphoid cells with preferential cytotoxicity in cells with a high proliferation index such as lymphoid malignancies. EXPERIMENTAL DESIGN: To generate proof-of-concept, a phase I/II trial was conducted in pet dogs (n = 38) with naturally occurring non-Hodgkin's lymphoma using different dose schedules of GS-9219. A subset of dogs was further evaluated with 3'-deoxy-3'-(18)F-fluorothymidine positron emission tomography/computed tomography imaging before and after treatment. RESULTS: The prodrug had a short plasma half-life but yielded high and prolonged intracellular levels of the cytotoxic metabolite PMEG diphosphate in peripheral blood mononuclear cells in the absence of detectable plasma PMEG. Dose-limiting toxicities were generally manageable and reversible and included dermatopathy, neutropenia, and gastrointestinal signs. Antitumor responses were observed in 79% of dogs and occurred in previously untreated dogs and dogs with chemotherapy-refractory non-Hodgkin's lymphoma. The median remission durations observed compare favorably with other monotherapies in dogs with non-Hodgkin's lymphoma. High 3'-deoxy-3'-(18)F-fluorothymidine uptake noted in lymphoid tissues before treatment decreased significantly after treatment (P = 0.016). CONCLUSIONS: GS-9219 was generally well tolerated and showed significant activity against spontaneous non-Hodgkin's lymphoma as modeled in pet dogs and, as such, supports clinical evaluation in humans.

Randomized crossover pharmacokinetic study of solvent-based paclitaxel and nab-paclitaxel.

PURPOSE: Abraxane (ABI-007) is a 130-nm albumin-bound (nab) particle formulation of paclitaxel, devoid of any additional excipients. We hypothesized that this change in formulation alters the systemic disposition of paclitaxel compared with conventional solvent-based formulations (sb-paclitaxel; Taxol), and leads to improved tolerability of the drug. PATIENTS AND METHODS: Patients with malignant solid tumors were randomized to receive the recommended single-agent dose of nab-paclitaxel (260 mg/m(2) as a 30-minute infusion) or sb-paclitaxel (175 mg/m(2) as a 3-hour infusion). After cycle 1, patients crossed over to the alternate treatment. Pharmacokinetic studies were carried out for the first cycle of sb-paclitaxel and the first two cycles of nab-paclitaxel. RESULTS: Seventeen patients were treated, with 14 receiving at least one cycle each of nab-paclitaxel and sb-paclitaxel. No change in nab-paclitaxel pharmacokinetics was found between the first and second cycles (P = 0.95), suggesting limited intrasubject variability. Total drug exposure was comparable between the two formulations (P = 0.55) despite the dose difference. However, exposure to unbound paclitaxel was significantly higher after nab-paclitaxel administration, due to the increased free fraction (0.063 +/- 0.021 versus 0.024 +/- 0.009; P < 0.001). CONCLUSION: This study shows that paclitaxel disposition is subject to considerable variability depending on the formulation used. Because systemic exposure to unbound paclitaxel is likely a driving force behind tumoral uptake, these findings explain, at least in part, previous observations that the administration of nab-paclitaxel is associated with augmented antitumor efficacy compared with solvent-based paclitaxel.

Protein nanoparticles as drug carriers in clinical medicine.

Solvent-based delivery vehicles for chemotherapy agents have been instrumental in providing a means for hydrophobic agents to be administered intravenously. These solvents, however, have been associated with serious and dose-limiting toxicities. Solvent-based formulations of taxanes, a highly active class of cytotoxic agents, are associated with hypersensitivity reactions, neutropenia, and neuropathy. Nanoparticle technology utilizing the human protein albumin exploits natural pathways to selectively deliver larger amounts of drug to tumors while avoiding some of the toxicities of solvent-based formulations. 130 nM albumin-bound (nab) paclitaxel (nab-paclitaxel; Abraxane) was recently approved for use in patients with metastatic breast cancer who have failed combination therapy. In a randomized, phase III study in metastatic breast cancer, nab-paclitaxel was found to have improved efficacy and safety compared with conventional, solvent-based paclitaxel. Preliminary data also suggest roles for nab-paclitaxel as a single agent and in combination therapy for first-line treatment of metastatic breast cancer as well as in other solid tumors, including non-small-cell lung cancer, ovarian cancer, and malignant melanoma. The nab technology promises to have broad utility in cancer therapy, and clinical trials are underway using nab formulations of other water-insoluble anticancer agents such as docetaxel and rapamycin.

Discovery of potent, selective, orally active, nonpeptide inhibitors of human mast cell chymase.

A series of beta-carboxamido-phosphon(in)ic acids (2) was identified as a new structural motif for obtaining potent inhibitors of human mast cell chymase. For example, 1-naphthyl derivative 5f had an IC50 value of 29 nM and (E)-styryl derivative 6g had an IC50 value of 3.5 nM. An X-ray structure for 5f.chymase revealed key interactions within the enzyme active site. Compound 5f was selective for inhibiting chymase versus eight serine proteases. Compound 6h was orally bioavailable in rats (F=39%), and orally efficacious in a hamster model of inflammation.

Phase I and pharmacokinetic trial of carboplatin and albumin-bound paclitaxel, ABI-007 (Abraxane) on three treatment schedules in patients with solid tumors.

PURPOSE: Albumin-bound paclitaxel, ABI-007 (Abraxane((R))), has a different toxicity profile than solvent-based paclitaxel, including a lower rate of severe neutropenia. The combination of ABI-007 and carboplatin may have significant activity in a variety of tumor types including non-small and small cell lung cancer, ovarian cancer, and breast cancer. The purpose of this study was to determine the maximum tolerated dose (MTD) of ABI-007, on three different schedules in combination with carboplatin. METHODS: Forty-one patients with solid tumors were enrolled, and received ABI-007 in combination with carboplatin AUC of 6 on day 1. Group A received ABI-007 at doses ranging from 220 to 340 mg/m(2) on day 1 every 21 days; group B received ABI-007 at 100 or 125 mg/m(2) on days 1, 8, and 15 every 28 days; and group C received ABI-007 125 or 150 mg/m(2) on days 1 and 8 every 21 days. Dose-limiting toxicities were assessed after the first cycle. Doses were escalated in cohorts of three to six patients. Fifteen patients participated in a pharmacokinetic study investigating the effects of the sequence of infusion. ABI-007 was infused first followed by carboplatin in cycle 1, and vice versa in cycle 2. RESULTS: The MTD of ABI-007 in combination with carboplatin was 300, 100, and 125 mg/m(2) in groups A, B, and C, respectively. Myelosuppression was the primary dose limiting toxicity. No unexpected or new toxicities were reported. Sequence of infusion did not affect either the pharmacokinetics of ABI-007 or the degree of neutropenia. Responses were seen in melanoma, lung, bladder, esophageal, pancreatic, breast cancer, and cancer of unknown primary. CONCLUSIONS: The recommended dose for phase II studies of ABI-007 in combination with carboplatin (AUC of 6) is 300, 100, 125 mg/m(2) for the schedules A, B, and C, respectively. The combination of ABI-007 and carboplatin is well tolerated and active in this heavily pretreated patient population.

Phase I and pharmacokinetics trial of ABI-007, a novel nanoparticle formulation of paclitaxel in patients with advanced nonhematologic malignancies.

PURPOSE: ABI-007 is a novel solvent-free, albumin-bound, 130-nm particle formulation of paclitaxel designed to avoid solvent-related toxicities and to deliver paclitaxel to tumors via molecular pathways involving an endothelial cell-surface albumin receptor (gp60) and an albumin-binding protein expressed by tumor cells and secreted into the tumor interstitium (secreted protein acid rich in cysteine). This study determined the maximum-tolerated dose (MTD) of ABI-007 monotherapy administered weekly (three weekly doses, repeated every 4 weeks) and assessed the pharmacokinetics of paclitaxel administered as ABI-007. PATIENTS AND METHODS: Patients with advanced nonhematologic malignancies received ABI-007 without premedication at dose levels from 80 to 200 mg/m(2) as a 30-minute intravenous infusion once a week for 3 weeks, followed by 1 week of rest (one cycle). RESULTS: Thirty-nine patients were treated with an average of five cycles of ABI-007; 33% of patients received > or = six cycles of treatment. MTDs for heavily and lightly pretreated patients were 100 and 150 mg/m(2), respectively; and the dose-limiting toxicities were grade 4 neutropenia and grade 3 peripheral neuropathy, respectively. Maximum paclitaxel concentration and area under the curve increased linearly with dose. Dose-dependent changes in plasma clearance did not occur. Partial responses were observed in five patients with breast, lung, and ovarian cancers, all of whom had previously been treated with paclitaxel containing polyoxyethylated castor oil in the formulation. CONCLUSION: This study demonstrated that weekly ABI-007 can be administered at doses exceeding those typically used for paclitaxel containing polyoxyethylated castor oil. Pharmacokinetics were linear over the dose range studied. Antitumor responses occurred in patients previously treated with paclitaxel containing polyoxyethylated castor oil.

Facile dephosphonylation of beta-ketophosphonic acids: mechanistic studies.

[reaction: see text] We have found that beta-ketophosphonic acids can undergo facile dephosphonylation under fairly mild conditions. The rate of dephosphonylation is dependent on the electronic nature of the substituent on the carbon atom alpha to phosphorus, with electron-withdrawing groups accelerating the process. 31P NMR studies were used to probe the mechanism for the process.

Initial clinical trial of oral TAC-101, a novel retinoic acid receptor-alpha selective retinoid, in patients with advanced cancer.

PURPOSE: The goals of this study were to determine the safety, toxicity, and pharmacokinetics of TAC-101, a novel synthetic retinoic acid receptor-alpha (RAR-alpha) selective retinoid, in patients with advanced cancer. PATIENTS AND METHODS: Twenty-nine patients at two centers received oral TAC-101 at doses ranging from 12 to 34 mg/m(2)/d. Pharmacokinetic sampling was performed on days 1 and 28. RESULTS: The most frequent toxicities were myalgia/arthralgia, fatigue, and triglyceridemia. No dose-limiting toxicities were observed within the first 28 days up to 28 mg/m(2). However, seven of 21 patients experienced venous thromboembolic events (VTEs) during TAC-101 treatment. Eight additional patients who received 34 mg/m(2) were treated after a hypercoagulable work-up to exclude potential risk factors for VTE, and two of eight patients subsequently experienced VTEs. The maximum tolerated dose was exceeded at 34 mg/m(2)/d within the first 28 days, with one grade 3 hypertriglyceridemia, two grade 3 myalgia/arthralgia, and one grade 3 fatigue. One patient with advanced non-small-cell lung cancer had a complete response. No other responses were observed. No autoinduction of metabolism was observed with dosing over 28 days. CONCLUSION: This is the first human clinical study with TAC-101, a RAR-alpha selective retinoid. Musculoskeletal toxicity and hypertriglyceridemia were observed characteristics of previously studied retinoids. The recommended phase II dose is 24 mg/m(2) with this treatment schedule. Alternative treatment schedules and prospective evaluation of thrombotic risk will be investigated in subsequent studies.

Phase I study of prolonged infusion Bryostatin-1 in patients with advanced malignancies.

PURPOSE: Bryostatin-1 is a compound known to inhibit protein kinase C expression. Clinical trials have focused on administration schedules ranging from 1 hour to 72 hour infusions. Preclinical data suggest that the down regulation of the target PKC occurs only as long as the drug is being infused. Therefore we performed a phase 1 clinical trial to determine the safety and recommended dose of prolonged infusion Bryostatin-1. EXPERIMENTAL DESIGN: Patients with advanced metastatic cancer were enrolled in this traditional phase 1 clinical trial utilizing prolonged infusion Bryostatin-1. The administration of Bryostatin-1 was initially begun at 96 hours and extended to 14 days. Doses were escalated using the 96 hour infusion time and then duration of infusion was increased. All patients underwent extensive sampling for determination of PKC levels as well as other key biologic end points. The determination of maximum tolerated dose and recommended phase two dose were based on toxicity. RESULTS: 38 patients were enrolled in the study. The recommended phase two doses were 24 mcg/m2 over five days, 16 mcg/m2 over six days and 8 mcg/m2 over 14 days. At the higher dose levels we demonstrated consistent down regulation of PKC-alpha. This was not observed at the low dose level. Toxicities were limited to myalgias and fatigue and were dose-related. The results of downstream signaling effects were less clear. MMP expression was not altered by treatment with Bryostatin-1. Only limited evidence for alterations in PKC activity as measured by expression of phosphorylated MAPK was observed. No objective responses were observed with five patients having prolonged stabilization of disease. CONCLUSIONS: Bryostatin-1 is safely administered over prolonged infusion schedules. There appears to be a dose response for PKC inhibition. Bryostatin-1 is a complicated compound as is the target PKC and its related signaling pathways. There is only limited clinical activity with this compound as a single agent; future studies should focus on combinations with other cytotoxics or targeted therapies.

A phase I trial of depsipeptide (FR901228) in patients with advanced cancer.

Depsipeptide (FR901228) is a bicyclic peptide isolated from Chromobacterium violaceum that has demonstrated potent in vitro cytotoxic activity against human tumor cell lines and in vivo efficacy against human tumor xenografts. The primary mechanism of action is through inhibition of histone deacetylase. Initial development was halted due to significant cardiac toxicity. Subsequent studies performed at the National Cancer Institute demonstrated administration without cardiotoxicity was possible by varying the schedule of administration. A phase I trial was designed to determine the maximum tolerated dose and toxicity profile when administered as a 4-hour infusion weekly x 3 with one week rest. 33 Patients with advanced, incurable cancers were enrolled into this trial and treated with doses of Depsipeptide ranging from 1 mg/m2 to 17.7 mg/m2. At doses above 5 mg/m2, we observed common symptoms of nausea, vomiting, fatigue, and anorexia. Subtle changes in ECGs were seen in several patients. However, no cardiac enzyme abnormalities or reduction in ejection fraction were observed. The MTD was defined as 13.3 mg/m2 with dose limiting toxicities being grade 3 thrombocytopenia and fatigue. Depsipeptide can be safely administered when given as a 4-hour infusion and further clinical trials are warranted.

Phase I/II trial of weekly intravenous 130-nm albumin-bound paclitaxel as initial chemotherapy in patients with stage IV non-small-cell lung cancer.

PURPOSE: Nanoparticle albumin-bound paclitaxel (NAB-paclitaxel) is an albumin-bound formulation of paclitaxel that has demonstrated improved efficacy compared with paclitaxel in the treatment of metastatic breast cancer. We undertook this trial to determine the maximum-tolerated dose (MTD) and single-agent activity of NAB-paclitaxel administered on a weekly basis to patients with stage IV non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: This was an open-label, single-arm, phase I/II study. Patients were treated with NAB-paclitaxel intravenously during 30 minutes without corticosteroid or antihistamine premedications on days 1, 8, and 15 of a 28-day cycle. Radiologic tumor assessment was performed every 8 weeks. RESULTS: Dose levels of 100 and 125 mg/m(2) were tolerated without dose-limiting toxicities (DLTs). At 150 mg/m(2) the MTD was exceeded; two of three patients experienced a DLT (grade 3 sensory neuropathy and febrile neutropenia). The 125 mg/m(2) dose level was expanded and determined to be the MTD. A total of 40 patients were treated at 125 mg/m(2). The objective response rate was 30% (12 of 40 patients; 95% CI, 16% to 44%), median time to progression was 5 months (95% CI, 3 to 8 months), and median overall survival was 11 months (95% CI, 7 months to not reached). The 1-year survival was 41%. CONCLUSION: NAB-paclitaxel 125 mg/m(2) administered on days 1, 8, and 15 of a 28-day cycle was well tolerated and demonstrated encouraging single-agent activity. No corticosteroid premedication was administered and no hypersensitivity reactions were seen. Additional studies of single-agent NAB-paclitaxel as well as platinum-based combinations are warranted.

A new family of Fisher-curves estimates Fisher's alpha more accurately.

Fisher's alpha is a satisfactory scale-independent indicator of biodiversity. However, alpha may be underestimated in communities in which the spatial arrangement of individuals is strongly clustered, or in which the total number of species does not tend to infinity. We have extended Fisher's curve to allow for an accurate calibration of Fisher's alpha in such communities. In spite of its good performance, the use of this extended curve is complicated by its optimization procedure. Therefore, we have simulated the extended Fisher curve by modifying the smooth expolinear curve, using three ecologically meaningful parameters only, i.e. Fisher's alpha, a coefficient describing the effects of clustering and the maximum number of species. The resulting equations successfully describe species-individual relationships from both spatial and temporal observations on both plant and animal communities. This family of equations combines three advantages: Fisher's alpha can be quantified more accurately, the number of estimated parameters is flexible and can be kept to a minimum, while all parameters can legitimately be compared across sites.

Phase I trial of orally administered CEP-701, a novel neurotrophin receptor-linked tyrosine kinase inhibitor.

PURPOSE: A phase I clinical trial in patients with advanced carcinomas was conducted using the orally available neurotrophin receptor-linked tyrosine kinase receptor inhibitor, CEP-701. The objectives were to determine the maximum tolerated dose (MTD), dose-limiting toxicities, and pharmacokinetic profile of this orally administered agent. PATIENTS AND METHODS: A total of 30 patients were accrued to receive escalating BID doses of CEP-701 in cycles lasting 28 days. Between 3 and 6 patients were enrolled at each dose level. Once the MTD was determined, nine de novo patients were recruited to receive that level of drug. Pharmacokinetic studies were performed after the first dose, with additional sampling to assess intraindividual variability. RESULTS: The dosages ranged from 5 mg BID to 160 mg BID. While the criteria for MTD were not met at the dose levels administered, DLTs were observed at 80 and 120 mg BID. Treatment related adverse events, especially of the gastrointestinal system, made CEP-701 poorly tolerated at dosages above 40 mg BID. While CEP-701 did not produce an objective tumor response in any patient, 7 of the 30 patients received treatment for 3 months or more, including 3 who were on study with stable disease for more than 6 months. Orally administered CEP-701 was rapidly absorbed, with a mean t(max) between 1 and 3 hours. At higher dose levels, serum drug levels showed greater than dose-proportional increases by Day 28 versus Day 1. CONCLUSION: CEP-701 40 mg BID was well tolerated by patients with advanced malignancy and is the recommended dose level for planned phase II trials. Further study is necessary to determine the clinical efficacy of this novel new chemotherapeutic agent.

Nonpeptide inhibitors of cathepsin G: optimization of a novel beta-ketophosphonic acid lead by structure-based drug design.

The serine protease cathepsin G (EC 3.4.21.20; Cat G), which is stored in the azurophilic granules of neutrophils (polymorphonuclear leukocytes) and released on degranulation, has been implicated in various pathological conditions associated with inflammation. By employing high-throughput screening, we identified beta-ketophosphonic acid 1 as a moderate inhibitor of Cat G (IC(50) = 4.1 microM). We were fortunate to obtain a cocrystal of 1 with Cat G and solve its structure by X-ray crystallography (3.5 A). Structural details from the X-ray analysis of 1.Cat G served as a platform for optimization of this lead compound by structure-based drug design. With the aid of molecular modeling, substituents were attached to the 3-position of the 2-naphthyl ring of 1, which occupies the S1 pocket of Cat G, to provide an extension into the hydrophobic S3 region. Thus, we arrived at analogue 7 with an 80-fold potency improvement over 1 (IC(50) = 53 nM). From these results, it is evident that the beta-ketophosphonic acid unit can form the basis for a novel class of serine protease inhibitors.