It is found in high concentrations in the vomiting center of the brain, and, when activated, it results in a vomiting reflex. In addition to this it also plays a key part in the transmission of pain impulses from the peripheral receptors to the central nervous system. Aprepitant has been shown to inhibit both the acute and delayed emesis induced by cytotoxic chemotherapeutic drugs by blocking substance P landing on receptors in the brains neurons. Positron emission tomography (PET) studies, have demonstrated that aprepitant can cross the blood brain barrier and bind to NK1 receptors in the human brain. It has also been shown to increase the activity of the 5-HT3 receptor antagonists ondansetron and the corticosteroid dexamethasone, which are also used to prevent nausea and vomiting caused by chemotherapy.Before clinical testing, a new class of therapeutic agent has to be characterized in terms of preclinical metabolism and excretion studies. Average bioavailability is found to be around 60-65%. Aprepitant is metabolized primarily by CYP3A4 with minor metabolism by CYP1A2 and CYP2C19. Seven metabolites of aprepitant, which are only weakly active, have been identified in human plasma. As a moderate inhibitor of CYP3A4, aprepitant can increase plasma concentrations of co-administered medicinal products that are metabolized through CYP3A4. Specific interaction has been demonstrated with oxycodone, where aprepitant both increased the efficacy and worsened the side effects of oxycodone; however it is unclear whether this is due to CPY3A4 inhibition or through its NK-1 antagonist action.
Eravacycline (TP-434, Xerava) is a synthetic halogenated tetracycline class antibiotic by Tetraphase Pharmaceuticals. It is closely related to tigecycline. It has a broad spectrum of activity including many multi-drug resistant strains of bacteria. Phase III studies in complicated intra-abdominal infections (cIAI) and complicated urinary tract infections (cUTI) were recently completed with mixed results. Eravacycline was granted fast track designation by the FDA and is currently available in USA. Medical uses
Eravacycline has shown broad spectrum of activity against a variety of Gram-positive and Gram-negative bacteria, including multi-drug resistant strains, such as methicillin-resistant Staphylococcus aureus (MRSA) and carbapenem-resistant Enterobacteriaceae. It is currently being formulated as for intravenous and oral administration. Spectrum of activity
Gram-positive organisms
Staphylococcus aureus (both methicillin-resistant and sensitive strains)
Streptococcus pneumoniae
Enterococcus faecalis
Enterococcus faecium (including vancomycin resistant strains)

Gram-negative organisms
Acinetobacter baumannii
Stenotrophomonas maltophilia
Haemophilus influenzae
Moraxella catarrhalis
Neisseria gonorrhoeae
Enterobacteriaceae
Escherichia coli (including ESBL-producing strains)
Klebsiella pneumoniae (including carbapenem resistant strains)
Klebsiella oxytoca
Enterobacter species
Citrobacter species
Proteus mirabilis
Serratia marcescensSimilar to other tetracycline derivatives, eravacycline is poorly active against Pseudomonas aeruginosa with a MIC90 = 16 mcg/mL (range 0.06-64 mcg/mL). Eravacycline maintains in-vitro activity against Enterobacteriaceae carrying the mcr-1 gene responsible for polymyxin b/colistin resistance. Clinical trials
Current and past clinical trial information:
https://clinicaltrials.gov/ct2/results?cond=&term=eravacycline&cntry1=&state1=&recrs=

Phase 3 trials
Complicated Intra-abdominal infections (IGNITE 1)
The IGNITE 1 trial compared twice-daily IV eravacycline to once-daily ertapenem for the treatment of cIAI. A total of 541 patients were included and eravacycline demonstrated noninferiority to ertapenem. An additional pivotal phase 3 study (IGNITE 4) is planned for late 2016 with initial results likely available in the fourth quarter of 2017.