Phase I safety, pharmacokinetic, and pharmacodynamic study of the oral phosphatidylinositol-3-kinase and mTOR inhibitor BGT226 in patients with advanced solid tumors

BACKGROUND

This phase I dose-escalation study investigated the maximum tolerated dose (MTD), safety, pharmacokinetics, pharmacodynamics (PDs), and preliminary antitumor activity of BGT226, a potent, oral dual phosphatidylinositol-3-kinase (PI3K)/mammalian target of rapamycin inhibitor.

PATIENTS AND METHODS

Fifty-seven patients with advanced solid tumors received BGT226 2.5-125 mg/day three times weekly (TIW). Dose escalation was guided by an adaptive Bayesian logistic regression model with overdose control. Assessments included response per RECIST, [18F]-fluorodeoxyglucose uptake, and phosphorylated-S6 in skin and paired tumor samples.

RESULTS

Three patients (125 mg cohort) had dose-limiting toxic effects (grade 3 nausea/vomiting, diarrhea). BGT226-related adverse events included nausea (68%), diarrhea (61%), vomiting (49%), and fatigue (19%). BGT226 demonstrated rapid absorption, variable systemic exposure, and a median half-life of 6-9 h. Seventeen patients (30%) had stable disease (SD) as best response. Nine patients had SD for ≥16 weeks. Thirty patients (53%) achieved stable metabolic disease as assessed by [18F]-fluorodeoxyglucose-positron emission tomography; however, no correlation between metabolic response and tumor shrinkage according to computed tomography was observed. PD changes suggested PI3K pathway inhibition but were inconsistent.

CONCLUSIONS

The MTD of BGT226 was 125 mg/day TIW, and the clinically recommended dose was 100 mg/day TIW. Limited preliminary antitumor activity and inconsistent target inhibition were observed, potentially due to low systemic exposure.

Participation of Gs-proteins in the action of relaxin-like gonad-stimulating substance (GSS) for 1-methyladenine production in starfish ovarian follicle cells

Gonad-stimulating substance (GSS) in starfish is the only known invertebrate peptide hormone responsible for final gamete maturation, rendering it functionally analogous to gonadotropins in vertebrates. Recently, we purified GSS from radial nerves in the starfish Asterina pectinifera and identified the chemical structure as a heterodimer composed of two different peptides (A- and B-chain) with disulfide cross-linkages. This study examined the hormonal action of GSS on ovarian follicle cells obtained from ovaries in growing (stage IV) and fully grown (stage V) stages, and particularly the mode of signal transduction. The action of GSS on 1-MeAde production by follicle cells in stage V was mediated through the production of cAMP. In contrast, GSS failed to induce 1-MeAde and cAMP production by follicle cells in stage IV. According to competitive experiments using radioiodinated and radioinert GSS, highly specific binding was observed in follicle cells, though their affinities and numbers in stage IV were inferior to those in stage V. Interestingly, Gsα was not detected immunologically in follicle cell membranes of stage IV. Gβ was also faint in stage IV. Although adenylyl cyclase activity in stage V was dose-dependently activated by GSS in the presence of GTP, neither GSS in the presence of GTP nor nonhydrolyzable GTP analogs were effective on the activity in stage IV. These findings strongly suggest that the failure of GSS to produce 1-MeAde is because of a lack of Gs-proteins in follicle cells at stage IV.

Hormonal action of relaxin-like gonad-stimulating substance (GSS) on starfish ovaries in growing and fully grown states

Gonad-stimulating substance (GSS) of starfish is the only known invertebrate peptide hormone responsible for final gamete maturation, rendering it functionally analogous to gonadotropins in vertebrates. Recently, we purified GSS from the radial nerves of the starfish Asterina pectinifera and identified the chemical structure as a relaxin-like peptide. This study examined the hormonal action of GSS on ovaries in the growing (stage IV) and fully grown states (stage V) of the starfish. The sensitivity of oocytes to 1-methyladenine (1-MeAde) as starfish maturation-inducing hormone was enhanced as oocytes enlarged in stage V. GSS-stimulated 1-MeAde production by ovarian follicle cells was also correlated with the size of oocytes. Although 1-MeAde production was observed in whole ovaries in stage V, GSS failed to induce 1-MeAde production in young ovaries (stage IV). This suggests that follicle cells in ovaries in a growing state (stage IV) are still unresponsive to the hormonal action of GSS. According to competitive experiments using radioiodinated and radioinert GSS, however, dissociation constant (K(d)) values and the number of binding sites for GSS were mostly constant in the ovaries from stages IV to V. These results strongly suggest that GSS receptors are expressed in follicle cells of ovaries in the growing state. The failure of GSS to induce 1-MeAde production in young ovaries may be due to the uncoupling of signal transduction from the receptor to 1-MeAde biosynthesis in follicle cells.

Involvement of the cAMP messenger system and extracellular Ca(2+) during hyposmotically-induced prolactin release in the Mozambique tilapia

In accord with its role in freshwater osmoregulation, prolactin (PRL) release from the tilapia pituitary is stimulated by small, physiologically relevant reductions in plasma osmolality, a response that is mediated by an acute influx of intracellular Ca(2+) through stretch-activated Ca(2+)channels. In the present study, the role of the calcium and cyclic AMP (cAMP) messenger system in the transduction of a response to a hyposmotic stimulus was examined using dispersed PRL cells and PRL cell membrane preparations from freshwater-acclimated tilapia. When PRL cells were treated with the phosphodiesterase (PDE) inhibitor, 3-isobutyl-1-methylxanthine (IBMX) (100μM), significant increases in cAMP levels and PRL release were observed at 1h. Exposure to reduced medium osmolality (300 mOsmolal) in the presence of IBMX further augmented PRL release. Depletion of Ca(2+) from the incubation medium blocked PRL release even in the presence of IBMX. By contrast, exposure of PRL cells to cholera toxin (CTX), an activator of adenylyl cyclase (AC), stimulated PRL release and cAMP accumulation in both the presence and absence of extracellular Ca(2+). On the other hand, treatment with the Ca(2+) ionophore A23187, which elicits a large rise in intracellular free Ca(2+), reduced cAMP accumulation. Likewise, the AC activity of a PRL cell membrane preparation was reduced as extracellular Ca(2+) concentration increased from 0.1 to 1 μM. These results indicate that: (1) the stimulation of PRL release and cAMP formation by a fall in extracellular osmolality are Ca(2+)-dependent; (2) large increases in intracellular Ca(2+) attenuate cAMP formation; (3) direct agonists of cAMP messenger system, such as cholera toxin, however, stimulate PRL release independently of the extracellular Ca(2+). These findings add to the evidence that the osmosensitive response of the tilapia PRL cell is mediated through a Ca(2+)-dependent mechanism. Nevertheless, the present findings also suggest that tilapia PRL cells have the ability to rapidly augment release PRL both via a Ca(2+)-dependent manner and via a cAMP-dependent pathway in the absence of extracellular Ca(2+).

Phase I and pharmacokinetic study of lexatumumab (HGS-ETR2) given every 2 weeks in patients with advanced solid tumors

BACKGROUND

Lexatumumab (HGS-ETR2) is a fully human agonistic mAb to the tumor necrosis factor-related apoptosis-inducing ligand receptor 2 that activates the extrinsic apoptosis pathway and has potent preclinical antitumor activity.

MATERIALS AND METHODS

This phase 1, dose escalation study assessed the safety, tolerability, pharmacokinetics (PKs) and immunogenicity of lexatumumab administered i.v. every 14 days in patients with advanced solid tumors.

RESULTS

Thirty-one patients received lexatumumab over five dose levels (0.1-10 mg/kg). Most (26 of 31) received four or more cycles of treatment. One patient at 10 mg/kg experienced a possibly related dose-limiting toxicity of grade 3 hyperamylasemia. Nine patients achieved stable disease. One patient with chemotherapy-refractive Hodgkin's disease experienced a mixed response. Lexatumumab PKs were linear up to 10 mg/kg. At the 10 mg/kg dose, the mean (+/-standard deviation) t(1/2b) was 13.67 +/- 4.07 days, clearance was 4.95 +/- 1.93 ml/day/kg, V(1) was 45.55 ml/kg and V(ss) was 79.08 ml/kg, indicating that lexatumumab distributes outside the plasma compartment. No human antihuman antibodies were detected.

CONCLUSIONS

Lexatumumab can be safely administered every 14 days at 10 mg/kg. The PK profile supports this schedule. Further evaluation of lexatumumab at this dose schedule is warranted, including combination trials with other agents.

Expression and distribution of gonad-stimulating substance in various organs of the starfish Asterina pectinifera

Gonad-stimulating substance (GSS) is the first invertebrate gonadotropic neuropeptide hormone identified in a marine invertebrate, the starfish. Here, we show expression and distribution of GSS in various organs of the starfish Asterina pectinifera. Levels of GSS were high in the radial nerves and nerve ring. GSS was also observed in the cardiac stomachs and tube-feet, although in low amounts, but it was undetectable in the gonads and in the pyloric ceca. Reverse transcriptase-PCR revealed that the mRNA of GSS was transcribed mainly in the radial nerves.

A relaxin-like peptide purified from radial nerves induces oocyte maturation and ovulation in the starfish, Asterina pectinifera

Gonad-stimulating substance (GSS) of starfish is the only known invertebrate peptide hormone responsible for final gamete maturation, rendering it functionally analogous to the vertebrate luteinizing hormone (LH). Here, we purified GSS of starfish, Asterina pectinifera, from radial nerves and determined its amino acid sequence. The purified GSS was a heterodimer composed of 2 different peptides, A and B chains, with disulfide cross-linkages. Based on its cysteine motif, starfish GSS was classified as a member of the insulin/insulin-like growth factor (IGF)/relaxin superfamily. The cDNA of GSS encodes a preprohormone sequence with a C peptide between the A and B chains. Phylogenetic analyses revealed that starfish GSS was a relaxin-like peptide. Chemically synthesized GSS induced not only oocyte maturation and ovulation in isolated ovarian fragments, but also unique spawning behavior, followed by release of gametes shortly after the injection. Importantly, the action of the synthetic GSS on oocyte maturation and ovulation was mediated through the production of cAMP by isolated ovarian follicle cells, thereby producing the maturation-inducing hormone of this species, 1-methyladenine. In situ hybridization showed the transcription of GSS to occur in the periphery of radial nerves at the side of tube feet. Together, the structure, sequence, and mode of signal transduction strongly suggest that GSS is closely related to the vertebrate relaxin.

Phase I trial of NPI-2358 (a novel vascular disrupting agent) plus docetaxel

3571

Background: NPI-2358 is a vascular disrupting agent (VDA) that destabilizes tumor vascular endothelial cell architecture resulting in selective collapse of established tumor vasculature. In murine tumor models NPI-2358 produces tumor regression alone and synergistically with agents such as paclitaxel, docetaxel (TXT) and irinotecan, often with decreased toxicity. Methods: The objective was to determine the Recommended Phase 2 Dose (RP2D) of NPI-2358 in combination with TXT. Patients with previously treated advanced NSCLC or other malignancies where TXT use was appropriate were enrolled. Patients received 75 mg/m2 TXT every 21 days. NPI-2358 was administered IV 2 hours after TXT on Day 1, and alone on Day 8. The dose of NPI-2358 was escalated from the single agent biologic effect dose (BED) of 13.5 mg/m2 to the single agent RP2D of 30 mg/m2 using a 3+3 design. PK was assessed on Days 1 and 8. Results: 13 patients were enrolled of whom 10 had NSCLC. At all dose levels adverse events were consistent with those of both agents given alone. Adverse events commonly associated with NPI-2358 were seen, including nausea, vomiting, fatigue, fever, tumor pain and transient blood pressure elevations. One DLT of nausea, vomiting, dehydration and neutropenia occurred at 30mg/m2. PK analysis did not indicate a drug-drug interaction. Of the patients with NSCLC, 8 had measureable disease of which 2 demonstrated a partial response (PR), with 4 others having lesser regressions. The RP2D was thus 30 mg/m2 of NPI-2358 with 75 mg/m2 TXT. Conclusions: The combination of full dose NPI-2358 and TXT is tolerable. Although a limited data set, activity appears favorable relative to the 5–10% response rate reported with TXT alone in this population. Based on these results, efficacy is now being assessed in Phase 2 (the ADVANCE study), a randomized comparison of TXT ± 30 mg/m2 of NPI-2358 in 2nd- line NSCLC. Of note, entry criteria allow patients with squamous cell carcinoma, as VDAs do not appear to result in unfavorable outcomes associated with some other agents in this sub-population.

[Table: see text]

Preliminary study on the receptor of gonad-stimulating substance (GSS) as a gonadotropin of starfish

Previously, the gonad-stimulating substance (GSS) which acts as the gonadotropin was purified from the starfish (Asterina pectinifera) and subsequently, its structure was deciphered. In this study, artificial GSS was synthesized and its interaction with the receptors was examined further. According to competitive experiments using radioiodinated and radioinert GSS in various tissues of A. pectinifera, high specific bindings were observed in the ovarian follicle cells and testicular interstitial cells. Scatchard plot analysis also showed that K(d) values were about 4nM in follicle cells and about 7nM in interstitial cells. The numbers of binding sites in follicle cells were estimated to be about 3pmoles/mg protein and in interstitial cells to be about 1pmoles/mg protein. These strongly suggest that GSS receptors are distributed to follicle cells in female and interstitial cells in male, respectively.

Phase I pharmacokinetic (PK) and pharmacodynamic (PD) study of LBH589, a novel deacetylase (DAC) inhibitor given intravenously on a new once weekly schedule

14019

Background: LBH589 is a novel deacetylase inhibitor that inhibits proliferation of tumor cells at nanomolar levels. This phase I study tested the safety and tolerability of IV LBH589 once each week for 3 of 4 wks in pts with advanced solid tumors or lymphoma. Methods: LBH589 was administered IV over 30 min. on days 1, 8 and 15 of a 28-day cycle. Western blots on peripheral blood lymphocytes were used to study histone acetylation (HA). Plasma PK profiles were analyzed on Days 1 and 8. Results: Thirty five pts (median age: 70 yrs; 23M, 12F) have been treated on 3 dose levels [10 mg/m2 (8pts), 15 mg/m2 (8 pts), 20 mg/m2 (19 pts)] with the following tumor types: Cutaneous and peripheral T cell lymphoma (7 pts), prostate (6 pts), mesothelioma (4 pts), colon (3 pts) and other (15 pts). There was one dose-limiting toxicity (transient grade 4 thrombocytopenia) at 20 mg/m2, none at the lower doses. Other G3/G4 toxicities (all cycles) include: transient thrombocytopenia (G4–5 pts, G3–5 pts), neutropenia (G3–2 pts), anemia (G3–5 pts), G3 hypophosphatemia (1 pt), G3 hypokalemia (1 pt), G3 nausea (1 pt) and G3 pruritus (1 pt). Thrombocytopenia was transient. Of 2,042 ECGs, 1 pt had an increase in QTcF from baseline of > 60 msec another with a QTcF >500 msec, both at 20 mg/m2. There was a dose-dependent increase in HA 7 days after one dose with 43% (10 mg/m2), 50% (15 mg/m2) and 60% (20 mg/m2) of pts with increased acetylation. The LBH589 plasma conc. peaked at the end of the 0.5 hr infusion with a mean terminal half-life of 16 hr. Median Cmax achieved with 20 mg/m2 was 1,000 ng/mL (2.86 μM). The AUC0-inf increased linearly with IV doses of 10–20 mg/m2. One pt with CTCL achieved a complete response (CR) on cycle 3, Day 1; this pt had previously received oral LBH589 at 20 mg MWF, achieving a CR on cycle 6, Day 28 that lasted for 7 months. One peripheral T-Cell lymphoma pt achieved a partial response that has persisted for >7 months. One pt with prostate cancer has had a 26% reduction in nodal disease and > 50% drop in PSA in the first 2 cycles. Conclusions: The maximum tolerated dose of LBH589 given IV wkly on a 3 of 4 wk schedule is 20 mg/m2. This dose produced sustained PD effects and higher systemic exposure compared to oral LBH589. Preliminary evidence of antitumor activity has been observed.

No significant financial relationships to disclose.

Phase I study of oral LBH589, a novel deacetylase (DAC) inhibitor in advanced solid tumors and non-hodgkin’s lymphoma

3500

Background: LBH589 is a novel deacetylase inhibitor (DACi) which induces apoptosis of tumor cells at nanomolar levels. In this phase 1 study, we evaluated the safety and tolerability of LBH589 in pts with advanced solid tumors or non-hodgkins lymphoma. Methods: LBH589 was administered orally on Monday, Wednesday, and Friday (MWF) weekly. Western blots on peripheral blood lymphocytes were used to study histone acetylation (HA). Plasma PK profiles were analyzed on Days 1 and 15. Results: Thirty two pts have been treated (Median age 63 years; 18 M, 14 F). Pts received 15 mg (3), 30 mg (10), the dose-limiting toxicity level (DLT), or 20 mg (19), the maximum tolerated dose (MTD). Tumor types included: CTCL (10), renal cell (6), melanoma (6), prostate (4), hepatic (1), rhabodomyosarcoma (1), mesothelioma (1), colon (1), bladder (1), and parotid gland (1). Three DLTs were reported; G3 diarrhea and transient G4 thrombocytopenia at 30 mg and G3 fatigue at 20 mg. The most common adverse events were anorexia, nausea, fatigue, diarrhea and transient thrombocytopenia. Of the 1,057 ECGs, 1 pt (20 mg) had a QTcF of 503 msec, an isolated event after the first dose with no recurrence on continued therapy. The mean change in QTcF from baseline was < 10 msec during the first cycle in all cohorts. No increase in HA was seen at 15 mg, but did increase in 50% of pts at 72 hrs post dose in both the 20 mg and 30 mg cohorts. LBH589 was rapidly absorbed in plasma (Tmax 1.5 hr), then declined with a mean terminal half-life of 16 hrs. Cmax and AUC increased linearly with doses between 15–30 mg. Two cutaneous T- cell lymphoma (CTCL) pts achieved a complete response (5 and 7 months) and 4 CTCL pts attained a partial response (6.5, 8, 9 and 18+ months). Stable disease was achieved in 7 pts: CTCL-2 pts (2 and 3 months); RCC-2 pts (3.5 and 7 months); melanoma-1 pt (4 months), mesothelioma-1 pt (2.5 months) and parotid gland-1 pt (5 months). Fifteen pts progressed on treatment and 4 pts were not evaluable for response. Conclusions: At 20 mg MWF every week, LBH589 oral produced a sustained pharmacodynamic effect on HA for ≥72 hours post dose in 50% of pts. Cardiac data indicates no clinically-significant effect on QTcF. Preliminary evidence of tumor response was observed at this dose and schedule in CTCL pts.

No significant financial relationships to disclose.

Phase I evaluation of a 24-h infusion of TAS-106 every 3 weeks (wks) in patients (pts) with solid tumors

2513

Background: The nucleoside 3’-C-ethynylcytidine (TAS-106) is metabolized in cancer cells to ethynylcytidine triphosphate (ECTP), an inhibitor of RNA polymerases I, II, and III. TAS-106 has potent anticancer activity in broad range of human tumor xenografts. In prior clinical studies, bolus intravenous (IV) TAS-106 caused reversible dose-limiting peripheral neuropathy and the recommended phase II dose (RP2D) was 4.21 mg/m2 every 3 wks. Myelosuppression, asthenia, and mild nausea and vomiting were also common. In rats, 24-h TAS-106 infusions are better tolerated with equivalent efficacy. Therefore, a Phase I study of 24-h infusions of TAS-106 was initiated. Methods: Escalating doses TAS-106 infused over 24-h every 3 wks were administered to cancer patients with pharmacokinetic (PK) monitoring during the initial cycle. Toxicity and response were assessed using NCI CTC (v2) grade (gr) and RECIST, respectively. Plasma and urine TAS-106 concentrations were monitored using LC/MS/MS methods. Results: Overall, 33 pts were treated at the following dose levels: 2.82 (4 pts), 3.5 (5 pts), 4.38 (6 pts), 5.48 (4 pts) 6.85 (6 pts) and 8.56 mg/m2 (8 pts). At 8.56 mg/m2, 2 of 5 pts experienced neutropenic DLTs (febrile neutropenia and gr 4 neutropenia lasting greater than or equal to 3 days) No neuropathy DLTs were observed. At 6.85 mg/m2, gr 3 peripheral neuropathy in cycle 1 was observed in 1 patient, but no other DLTs occurred in 5 patients. Other common drug related toxicities occurring in any cycle included gr 1–2 fatigue (13 pts), gr 3–4 neutropenia (10 pts), gr 1 hand/foot syndrome (9 pts), gr 2–3 anemia (9 pts) gr 1 rash/skin exfoliation (10 pts), and peripheral neuropathy gr 1–2 (5 pts). No objective responses were seen; although 3 pts with parotid, adenoid cystic, and breast cancers demonstrated stable disease for 5, 6, and 7 months, respectively. Plasma concentrations increased with increasing dose, and at 6.85 mg/m2, the Cmax was 77.4±7.3 ng/mL, AUC 1,892±54 ng·h/mL, CL 102±13 mL/h/kg, VDss 1.37±.05 L/kg, and t1/2 was 9.85±1.47 h. Over 48 h, 62.1% of the administered dose of TAS-106 was excreted into the urine. Conclusions: Compared with bolus dosing, 24-h infusions of TAS-106 are better tolerated with less peripheral neuropathy. The RP2D for TAS-106 infused over 24-h every 3 wks is 6.85 mg/m2.

[Table: see text]

Incapacity of response to disulfide-reducing agent in Triton X-100-treated oocytes of starfish, Asterina pectinifera

Resumption of meiosis in starfish oocytes is induced by the natural maturation-inducing hormone, 1-methyladenine (1-MeAde). Oocyte maturation is also induced by the disulfide-reducing agent, dithiothreitol (DTT). Previous studies have shown that 1-MeAde controls meiosis by interacting with its receptors, which are located exclusively on oocyte plasma membrane. However, little is known about the mechanism of oocyte maturation induced by DTT. Thus, this study examined whether DTT interacts with 1-MeAde receptors to induce oocyte maturation. When oocytes were treated with Triton X-100, they failed to respond to 1-MeAde and DTT. Although the Triton X-100-treated oocytes recovered the capacity to respond to 1-MeAde during incubation in seawater, they remained unresponsive to DTT during seawater incubations. These results suggest that DTT does not interact with 1-MeAde receptors to induce oocyte maturation in starfish. It is possible that a protein essential for mediating DTT-induced maturation is eliminated from the oocytes surface following Triton X-100 treatment.

HGS-ETR2—A fully human monoclonal antibody to TRAIL-R2: Results of a phase I trial in patients with advanced solid tumors

3012

Background: HGS-ETR2 is a fully-human high-affinity monoclonal antibody that is agonistic to the Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand Receptor 2 (TRAIL-R2, DR5). TRAIL-R2 is expressed more widely on the surface of tumor cells than normal cells; binding of HGS-ETR2 to TRAIL-R2 leads to activation of the extrinsic apoptosis pathway. HGS-ETR2 shows anti-tumor activity at doses ≥ 0.3 mg/kg in xenograft models, both as a single agent and in combination with chemotherapeutic agents. Methods: This phase 1, dose-escalation study assessed the safety, tolerability, pharmacokinetics and immunogenicity of HGS-ETR2 administered IV every 14 days in patients with advanced solid tumors. Patients received HGS-ETR2 until disease progression or unacceptable toxicity. Tumor measurements were repeated every 2 months. Results: To date, 31 patients have received 167 courses of HGS-ETR2 over 5 dose levels: 0.1, 0.3, 1.0, 3.0 and 10.0 mg/kg q14 days. The majority (26 of 31) received at least 4 courses. One patient experienced a dose-limiting toxicity of grade 3 hyperamylasemia at the 10 mg/kg dose level. The event was determined to be possibly related to HGS-ETR2 and also possibly related to a nutritional supplement. Stable disease was achieved in 10 patients for 4 to 16 cycles. One patient with chemotherapy-refractive Hodgkin’s disease had a tumor regression of abdominal disease. HGS-ETR2 pharmacokinetics were linear up to 10 mg/kg. At the 10 mg/kg dose, the pharmacokinetics were characterized by a mean (SD) t1/2β of 11 (4) days, CL of 6.0 (0.7) mL/day, and V1 of 47 (8) mL/kg, slightly larger than the plasma volume. The 1.8-fold larger Vss of 85 (27) mL/kg indicates that HGS-ETR2 distributes outside the plasma compartment. Human anti-human antibody formation has not been detected. Conclusions: HGS-ETR2 can be safely administered every 14 days at doses up to and including 10 mg/kg. Further evaluation of HGS-ETR2 is planned, including studies of HGS-ETR2 in combination with chemotherapeutic agents.

[Table: see text]

Multi-targeted inhibition of the epidermal growth factor (EGFR) and vascular endothelial growth factor receptor (VEGFR) pathways: A phase I study of cetuximab (C), erlotinib (E), and bevacizumab (B) in patients with solid tumors

3005

Background: Complex interrelationships exist between the EGFR and VEGFR pathways. EGFR activation elicits cell proliferation, and downstream effects increase expression of VEGF. In renal cell carcinoma, mutations increase hypoxia inducible factor-1alpha, stimulating VEGF and transforming growth factor expression. Moreover, there is additive tumor inhibition from combined EGFR targeting with C, and a tyrosine kinase inhibitor. To maximally inhibit EGFR, and then inhibit downstream VEGFR activity, this phase I study was initiated to determine the maximum tolerated dose (MTD) of E with a fixed dose of C, and then the MTD of B with combined E and C in patients with advanced malignancies. Methods: Patients with advanced malignancies likely to express EGFR were entered in part 1 to daily oral E (starting at 100mg, planned initially to increase to 150 mg), with fixed dose C (400 mg/m2 loading and 250 mg/m2 IV weekly). Once the MTD was determined for E in combination C, part 2 incorporated the addition of escalating doses of B (5 mg/kg IV every 2 weeks, to increase to 10 mg/kg) to the combination of E and C. Results: 27 patients were entered and received 84 courses over 3 dose levels. In part 1 grade 3 rash occurred in 2 patients at E at 100 mg daily, and the MTD of E for this combination was 50 mg daily with standard dose C (12 patients treated). Other adverse events included rash, diarrhea, hypomagnesemia, and nausea. Part 2: B at 5 mg/kg IV q14 days can be added to the MTD of E with C, with additional non-dose limiting toxicities of headache, proteinuria, and hypertension. Durable stable disease has been observed in 4 patients with metastatic disease for 7 (sqaumous cell); 10+, 12, and 12+ (renal cell) months. Conclusions: The MTD for E combined with standard C is 50 mg daily. B at 5mg/kg can be combined safely with this combination and dose escalation is ongoing.

[Table: see text]

Inhibitory Effect of a SALMFamide Neuropeptide on Secretion of Gonad-Stimulating Substance from Radial Nerves in the Starfish Asterina pectinifera

In starfish, the peptide hormone gonad-stimulating substance (GSS) secreted from nervous tissue stimulates oocyte maturation to induce 1-methyladenine (1-MeAde) production by ovarian follicle cells. The SALMFamide family is also known to an echinoderm neuropeptide. The present study examined effect of SALMFamide 1 (S1) on oocyte maturation of starfish Asterina pectinifera. Unlike GSS, S1 did not induce spawning in starfish ovary. In contrast, S1 was found to inhibit GSS secretion from radial nerves by treatment with high K+ concentration. Fifty percent inhibition was obtained by 0.1 mM S1. S1 did not have any effect on GSS- and 1-MeAde-induced oocyte maturation. Following incubation with a S1 antibody and subsequently with rhodamine-conjugated second antibody, neural networks were observed in ovaries. The networks were restricted mainly to their surface with little evidence of immunoreactivity inside the basement membranes. This indicates that neural networks are distributed in the ovarian wall. The result further suggests that S1 plays a role in oocyte maturation to regulate GSS secretion from the nervous system.

Comparative studies on the energy metabolism in spermatozoa of four closely related species of sea urchins (genus Echinometra) in Okinawa

Sea urchins of the genus Echinometra are abundant on Okinawa reef flats in southern Japan. The Okinawan Echinometra is designated into four sympatric and closely related species: A, B, C, and D (Ea, Eb, Ec, and Ed). The sperm head size and shape gradually changes to become longer and more slender according to the following order: Ea, Eb, Ec, and Ed. To obtain information regarding speciation in Okinawan Echinometra, this study examined comparatively the energy production system of spermatozoa of Ea, Eb, Ec, and Ed. All spermatozoa contained cholesterol and several kinds of phospholipids. Glycogen, glucose, and triglyceride were present at extremely low levels. After incubation in sea-water, a decrease in the level of phosphatidylcholine (PC) was observed in all spermatozoa concomitantly with activation of motility and respiration. The hydrolysis of PC correlated with the activity of phospholipase A2. Interestingly, the amount of PC consumed, the respiratory rate, and the phospholipase A2 activity in spermatozoa of Ea and Eb were approximately two-fold higher than those of Ec and Ed. Ultrastructural studies showed that lipid bodies within mitochondria were present in the midpieces of all species of spermatozoa. They became small or disappeared after incubation in seawater. Thus, the results obtained strongly suggest that spermatozoa of Ea, Eb, Ec, and Ed all use PC located in the lipid bodies as a substrate for energy metabolism. Also, it seems likely that energy production activities in Ea and Eb spermatozoa are stronger than those in Ec and Ed. The properties of energy metabolism in different species of sea urchin may be related to their habitat.

Interaction of N1-substituted adenines with 1-methyladenine receptors of starfish oocytes in induction of maturation

Starfish oocytes are arrested naturally in the late G(2) phase of the first meiotic division. In response to the natural maturation-inducing hormone, 1-methyladenine (1-MA), oocytes undergo reinitiation of meiosis with germinal vesicle breakdown. We tested 10 newly synthesized N1-substituted adenines that are 1-MA analogues to analyze the interaction between 1-MA and its stereo-specific receptors on the oocyte plasma membranes of the starfish Asterina pectinifera. Among these analogues, 1-(beta-naphthylmethyl)adenine, 1-aminoadenine and 1-(p-nitrobenzyl)adenine played agonistic roles in the induction of oocyte maturation. 1-(o-Nitrobenzyl)adenine, 1-(m-nitrobenzyl)adenine, 1-phenethyladenine and 1-(p-nitrophenethyl)adenine had antagonist effects on 1-MA-induced oocyte maturation. These agonists and antagonists behaved competitively in the binding of [3H]1-MA to receptors in oocyte cortices. In contrast, 1-(alpha-naphthylmethyl)adenine, 1-(2,4-dinitrobenzyl)adenine and 1-(p-methoxybenzyl)adenine had no effects on oocyte maturation. Our results suggest that regional-specific sterical structures at the N1-site of adenine are important in the interaction between 1-MA and its receptors in oocytes. In addition, a negative charge at the N1-site of adenine is required for binding with the receptors.

[Effects of stimulus intensity on multifocal electroretinograms]

PURPOSE

To investigate origins of responses of the second order kernel components of multifocal electroretinograms (m-ERGs), the influence of stimulus intensities on the waveform were studied.

SUBJECTS AND METHODS

M-ERGs were recorded from 20 normal eyes of 14 normal adults using a Visual Evoked Response Imaging System with 19 hexagonal stimulus elements with light intensities of 6.3, 20, 63, 200, or 331 cd/m2. The response densities and implicit times of the first (N1, P1, N2) and the second order kernel components (P1, N1, P2, N2, P3, N3) of the m-ERGs were measured.

RESULTS

The components were divided into two groups based on the behavior of the each component to the stimulus intensity change. The first group consisted of all the first order kernel components and P1 and N1 of the second order kernel components whose response densities were significantly larger (p < 0.05) than those of components elicited by stimulus of one grade lower intensity. The second group consisted of N2, P3, and N3 of the second order kernel components whose response densities did not increase when the stimulus intensity was increased from 200 to 331 cd/m2.

CONCLUSION

It is probable that in the second order kernel components, the origin of P1, N1, and P2 is different from N2, P3, and N3 because the response to stimulus intensity of the two groups of components was different.

Three episodes of delayed hemolytic transfusion reactions due to multiple red cell antibodies, anti-Di, anti-Jk and anti-E

There is no report in which three episodes of delayed hemolytic transfusion reaction (DHTR) occurred from multiple antibodies to red cells (RBCs) in the course of treatment of a patient. This paper describes episodes of anemia and hyperbilirubinemia in concert with the development of three alloantibodies in a multiple transfused patient. The patient was a 71-year-old male suffering from valvular heart disease and hemophilia B with a history of transfusions. Although he received compatible RBCs from 14 donors as judged by a crossmatch test using the albumin-antiglobulin method, three episodes of DHTR occurred after surgery. The first hemolytic episode on day 7 after surgery was due to anti-Di(a) because of clinical and laboratory evidence which included jaundice, sudden increases in total bilirubin (T-Bil) and lactate dehydrogenase (LD) levels, and a decrease (2.2 g/dl) in hemoglobin (Hb) level. The second hemolytic episode on day 16 resulted from newly producted anti-Jk(b). The patient experienced fever, fatigue, nausea and anorexia, and laboratory data showed a second increase in T-Bil, a second decrease (3 g/dl) in Hb, and moderate elevations of blood urea nitrogen (BUN) and creatinine (CRE) levels. The third hemolytic episode on day 39 was due to anti-E. The patient complained of fever and fatigue and had a third unexplained drop (1.5 g/dl) in Hb despite no bleeding. This is the first reported case in which three episodes of DHTR occurred from different red cell antibodies.

Activity of exemestane in metastatic breast cancer after failure of nonsteroidal aromatase inhibitors: a phase II trial

PURPOSE

To evaluate the antitumor activity and toxicity of a new steroidal aromatase inactivator, exemestane, in postmenopausal women with metastatic breast cancer who had progressive disease (PD) after treatment with a nonsteroidal aromatase inhibitor.

PATIENTS AND METHODS

In this phase II trial, eligible patients were treated with exemestane 25 mg daily (n = 241) followed, at the time PD was determined, by exemestane 100 mg daily (n = 58).

RESULTS

On the basis of the intent-to-treat analysis by independent review, exemestane 25 mg produced objective responses in 6.6% of patients (95% confidence interval [CI], 3.8% to 10.6%) and overall success (complete response + partial response + no change for 24 weeks or longer) in 24.3% (95% CI, 19.0% to 30.2%). The median durations of objective response and overall success were 58.4 weeks (95% CI, 49.7 to 71.1 weeks) and 37.0 weeks (95% CI, 35.0 to 39.4 weeks), respectively. Increasing the dose of exemestane to 100 mg upon the development of PD produced one partial response (1.7%; 95% CI, 0.0% to 9.2%). Both dosages were well tolerated and were discontinued because of adverse events in only 1.7% of patients.

CONCLUSION

Exemestane 25 mg once daily seems to be an attractive alternative to chemotherapy for the treatment of patients with metastatic breast cancer after multiple hormonal therapies have failed.