7049 Background: L-asparaginase (ASNase) is a key drug in the treatment of ALL. ASNase therapy aims to lower serum asparagine (ASN) levels, but no critical minimum value for efficacy has yet been established. ASN levels are difficult to measure accurately due to ex vivo depletion during the time required to harvest plasma from blood samples and to quench the enzyme, even if samples are immediately processed and stored on ice. Eryaspase is an investigational product under development. Following infusion of eryaspase, ASN is actively transported into RBCs, where it is hydrolyzed by the encapsulated ASNase. Methods: This randomized Phase 2/3 study enrolled pts with relapsed ALL. The co-primary endpoints were the mean duration of ASNase activity > 100 U/L and incidence of allergic reactions during the induction phase. Secondary endpoints were safety, complete remission (CR), pharmacokinetics (PK), and pharmacodynamics (PD). Pts (n = 80, age:1-55 years) were randomized to eryaspase or native ASNase. Results: The mean duration of ASNase activity > 100 U/L measured in whole blood was significantly higher with eryaspase (18.9 ± 5.3 days) compared with native ASNase (8.5 ± 6.6 days). In both treatment arms, ASN depletion ≤2 µM was maintained for ~7 days in 75% of pts. The mean duration of ASN depletion ≤2 µM was 6.0 ± 5.0 and 11.6 ± 7.3 days with eryaspase and native ASNase, respectively. Exploratory receiver operating characteristic (ROC) analysis suggested that an optimal threshold of ≤ 7.55 µM ASN on Day 6 correlated with CR with a positive predictive value of 0.88. Conclusions: The assumed requirement for prolonged ASN depletion in patients receiving ASNase therapy is likely to be an overestimation caused by ex-vivo depletion that is observed with free ASNase. Measurement of ASN depletion in pts treated with eryaspase are less prone to such error. Accordingly, the efficacy of encapsulated ASNase cannot be accurately compared with that of free ASNase based on ASN depletion. ASN depletion ≤2 μM may not be needed with eryaspase, and a level ≤7.55 µM correlated with CR. Clinical trial information: NCT01518517.

A dichloromethane extract from leaves of Searsia pyroides potentiated gamma aminobutyric acid- induced chloride currents by 171.8 +/- 54% when tested at 100 mu g/mL in Xenopus oocytes transiently expressing gamma aminobutyric acid type A receptors composed of alpha(1)beta(2)gamma(2)s subunits. In zebrafish larvae, the extract significantly lowered pentylenetetrazolprovoked locomotion when tested at 4 mu g/mL. Active compounds of the extract were tracked with the aid of HPLC-based activity profiling utilizing a previously validated zebrafish larval locomotor activity assay. From two active HPLC fractions, compounds 1-3 were isolated. Structurally related compounds 4-6 were purified from a later eluting inactive HPLC fraction. With the aid of H-1 and C-13 NMR and high-resolution mass spectrometry, compounds 1-6 were identified as analogues of anacardic acid. Compounds 1-3 led to a concentration-dependent decrease of pentylenetetrazol-provoked locomotion in the zebrafish larvae model, while 4-6 were inactive. Compounds 1-3 enhanced gamma aminobutyric acid-induced chloride currents in Xenopus oocytes in a concentration-dependent manner, while 4-6 only showed marginal enhancements of gamma aminobutyric acid- induced chloride currents. Compounds 2, 3, and 5 have not been reported previously.

ABSTRACT Malaria remains a great burden on humanity. Although significant advances have been made in the prevention and treatment of malaria, malaria control is now hindered by an increasing tolerance of the parasite to one or more drugs within artemisinin combination therapies; therefore, an urgent need exists for development of novel and improved therapies. The University of the Free State Chemistry Department previously synthesized an antimalarial compound, NP046. In vitro studies illustrated an enhanced efficacy against Plasmodium falciparum . However, NP046 showed low bioavailability. Efforts to enhance the bioavailability of NP046 have resulted in the synthesis of a number of aminoalkylated diarylpropanes, including NP085 and NP102. Pharmacokinetic studies were conducted in C57BL/6 mice, with 15 mg/kg NP085 or NP102 administered orally and the 5 mg/kg NP085 or NP102 administered intravenously. Blood samples were collected by means of tail bleeding at predetermined time intervals. Drug concentrations were determined using a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, and subsequently pharmacokinetic modeling was done for both compounds. NP085 and NP102 were incubated in vitro with human and mouse liver microsomes. Both compounds were also subjected to a parallel artificial membrane permeation assay. In vitro studies of NP085 and NP102 illustrated that both of the compounds are rapidly absorbed and undergo rapid hepatic metabolism. The maximum concentration of drug ( C max ) obtained following oral administration of NP085 and NP102 was 0.2 ± 0.4 and 0.7 ± 0.3 μM, respectively; the elimination half-life of both compounds was 6.1 h. NP085 and NP102 showed bioavailability levels of 8% and 22%, respectively.

L-asparaginase (L-ASP) is an enzyme-drug that has been used for decades to treat acute lymphoblastic leukemia (ALL). The red blood cell (RBC)-encapsulated L-ASP product GRASPA (eryaspase) was introduced recently with the goal of reducing L-ASP side effects without compromising efficacy. We previously showed in a Phase 2/3 trial that none of the patients treated with GRASPA had evidence of allergic reactions during induction compared to 46% of patients treated with non-encapsulated L-ASP (Baruchel et al., ASH, 2015). Similarly, evidence of pancreatic or hepatic toxicities were substantially lower with GRASPA compared to native L-ASP. Hence, GRASPA exhibits a clear benefit over L-ASP in terms of toxicity profile.

A series of readily synthesized and inexpensive aminoalkylated chalcones and diarylpropane analogues (1-55) were synthesized and tested against chloroquinone-sensitive (D10 and NF54) and -resistant (Dd2 and K1) strains of Plasmodium falciparum. Hydrogenation of the enone to a diarylpropane moiety increased antiplasmodial bioactivity significantly. The influence of the structure of the amine moiety, A-ring substituents, propyl vs ethyl linker, and chloride salt formation on further enhancing antiplasmodial activity was investigated. Several compounds have IC₅₀ values similar to or better than chloroquine (CQ). The most active compound (26) had an IC₅₀ value of 0.01 μM. No signs of resistance were detected, as can be expected from compounds with structures unrelated to CQ and other currently used antimalarial drugs. Toxicity tests (in vitro CHO cell assay) gave high SI indices.

Background: Even though malaria is a completely preventable and treatable disease, it remains a threat to human life and a burden to the global economy due to the emergence of multiple-drug resistant malaria parasites. According to the World Malaria Report 2013, in 2012 there were an estimated 207 million malaria cases and 627,000 deaths. Thus, the discovery and development of new, effective anti-malarial drugs are required. To achieve this goal, the Department of Chemistry at the University of the Free State has synthesized a number of novel amino-alkylated chalcones and analogues, which showed in vitro anti-malarial activity against both chloroquine-sensitive and chloroquine-resistant Plasmodium falciparum strains. The lead compound (NP046) was selected for a comprehensive pharmacokinetic (PK) and in vivo efficacy evaluation in a mouse model.Methods: In vivo efficacy: Water solutions of NP046 were administered orally at 50 and 10 mg/kg using oral gavage and IV at 5 and 1 mg/kg via the dorsal penile vein to Plasmodium berghei (ANKA strain) infected male C57BL/6 mice (n = 5), once a day for four days. Blood samples were collected via tail bleeding in tubes containing phosphate buffer saline (PBS) on day five to determine the % parasitaemia by flow cytometry. In vivo PK: NP046 solutions in water were administered orally (50 and 10 mg/kg) and IV (5 mg/kg) to male C57BL/6 mice (n = 5). Blood samples were collected via tail bleeding into heparinized tubes and analysed using a validated LC-MS/MS assay. Data obtained from the concentration-time profile was evaluated using Summit PK software to determine the PK parameters of NP046.Results: NP046 inhibited parasite growth for the oral and IV groups. Better parasite growth inhibition was observed for the IV group. The PK evaluation of NP046 showed low oral bioavailability (3.2% and 6% at 50 mg/kg and 10 mg/kg dose, respectively and a moderate mean half-life ranging from 3.1 to 4.4 hours.Conclusion: Even though the oral bioavailability of NP046 is low, its percentage parasite growth inhibition is promising, but in order to improve the oral bioavailability, structure-activity-relationship (SAR) optimization studies are currently being conducted.

Malaria is one of the most lethal and life-threatening killer infectious diseases in the world, and account for the deaths of more than half a million people annually. Despite the remarkable achievement made in preventing and eradicating malaria, it still remains a threat to the public health and a burden to the global economy due to the emergence of multiple-drug resistant malaria parasites. Therefore, the need to develop new anti-malarial drugs is crucial. The chemistry department at the University of Cape Town synthesized a number of new CQ-like derivatives (TK-series), and evaluated them for in vitro activity against both CQ-sensitive and -resistant Plasmodium falciparum strains, and for general cytotoxicity against a Chinese Hamster Ovarian (CHO) mammalian cell line. The lead compounds from the TK-series were selected for a comprehensive pharmacokinetic (PK) evaluation in a mouse model.

A new class of 4-aminoquinolines was synthesized and evaluated in vitro for antiplasmodial activity against both the chloroquine-sensitive (3D7) and -resistant (K1 and W2) strains. The most active compounds 3c-3e had acceptable cytotoxicity but showed strong inhibition toward a panel of cytochrome P450 enzymes in vitro. Pharmacokinetic studies on 3d and 3e in mice showed that they had moderate half-life (4-6 h) and low oral bioavailability. The front runner compound 3d exhibited moderate inhibition of the malaria parasite on P. berghei infected mice following oral administration (5 mg/kg), achieving reduction of parasitemia population by 47% on day 7.

During the development of a method for quantitative determination of venlafaxine and its major metabolite O-desmethylvenlafaxine, elevated concentrations of the analyte as well as co-eluting matrix compounds caused ion suppression. This ion suppression was inconsistent and therefore influenced the reproducibility of detection. The use of atmospheric pressure photoionization (APPI) in the positive mode was investigated as a tool to circumvent this problem. Employing APPI resulted in negligible ion suppression and increased linearity of the concentration range. A selective, sensitive and rapid liquid chromatography/tandem mass spectrometry method for the determination of venlafaxine and its major metabolite O-desmethylvenlafaxine in human plasma was developed. The analyte was extracted from plasma into tert-butyl methyl ether followed by back extraction into 2% formic acid. An Agilent 1100 high-performance liquid chromatography (HPLC) system, employing reversed-phase chromatography on a cyano column, coupled to an Applied Biosystems API 3000 triple quadrupole mass spectrometer set to multiple reaction monitoring (MRM) mode, was used for separation and detection of the analytes. The method was validated between 2.36-605 ng per mL with a mean recovery of approximately 88% for both parent compound and metabolite analytes. APPI technology was employed to improve the reproducibility of detection enabling rapid, selective and sensitive quantification of venlafaxine and O-desmethylvenlafaxine in human plasma samples.