APD-334 (Etrasimod) was discovered as part of our internal effort to identify potent, centrally available, functional antagonists of the S1P1 receptor for use as next generation therapeutics for treating multiple sclerosis (MS) and other autoimmune diseases. APD334 is a potent functional antagonist of S1P1 and has a favorable PK/PD profile, producing robust lymphocyte lowering at relatively low plasma concentrations in several preclinical species. This new agent was efficacious in a mouse experimental autoimmune encephalomyelitis (EAE) model of MS and a rat collagen induced arthritis (CIA) model and was found to have appreciable central exposure. APD-334 has therapeutic potential in immune and inflammatory-mediated diseases such as ulcerative colitis, Crohn’s disease, and atopic dermatitis.

Siponimod (BAF312) is a dual agonist at the sphingosine-1 phosphate receptors, S1PR1 and S1PR5. The S1P receptor is commonly found on the surface of specific cells residing in the central nervous system (CNS), that are responsible for causing CNS damage that drives loss of function in secondary progressive multiple sclerosis (SPMS). Siponimod (BAF312) enters the brain and by binding to these specific receptors, may prevent the activation of these harmful cells, helping to reduce the loss of physical and cognitive function associated with SPMS.

Fostamatinib is a pro-drug of a Syk inhibitor R406 initially developed by Rigel Pharmaceuticals, but then in-licensed by AstraZeneca. It reached phase III of clinical trials for such diseases as Rheumatoid Arthritis and Immune Thrombocytopenic Purpura, however, AstraZeneca decided not to proceed with regulatory filings and return the rights to the compound to Rigel Pharmaceuticals. In 2018 the drug was approved by the FDA for treatment of chronic immune thrombocytopenia. Fostamatinib is being developed for Autoimmune Hemolytic Anemia (phase II), graft versus host disease (phase I) and ovarian cancer (phase I).

Tedizolid phosphate is an oxazolidinone prodrug which in the body is dephosphorylated to the active compound tedizolid. The antibacterial activity of tedizolid is mediated by binding to the 50S subunit of the bacterial ribosome resulting in inhibition of protein synthesis. Tedizolid inhibits bacterial protein synthesis through a mechanism of action different from that of other non-oxazolidinone class antibacterial drugs; therefore, cross-resistance between tedizolid and other classes of antibacterial drugs is unlikely. Tedizolid is bacteriostatic against Gram Positive bacteria such as enterococci, staphylococci, and streptococci. No drug-drug interactions were identified with tedizolid.

Linezolid is an antibiotic used for the treatment of infections caused by Gram-positive bacteria that are resistant to other antibiotics. Linezolid appears to be unique in that it blocks the initiation of protein production. Most common adverse reactions include diarrhea, vomiting, headache, nausea, and anemia. Linezolid has the potential for interaction with adrenergic and serotonergic agents. And with monoamine oxidase inhibitors because it’s nonselective inhibitor of monoamine oxidase.

Fludarabine or fludarabine phosphate is a chemotherapy drug used in the treatment of hematological malignancies (cancers of blood cells such as leukemias and lymphomas). It is a purine analog, which interferes with DNA synthesis. Fludarabine phosphate is a fluorinated nucleotide analog of the antiviral agent vidarabine, 9-β-D-arabinofuranosyladenine (ara-A), that is relatively resistant to deamination by adenosine deaminase. Fludarabine (marketed as fludarabine phosphate under the trade name Fludara) is a chemotherapy drug used in the treatment of hematological malignancies. Fludarabine phosphate is rapidly dephosphorylated to 2-fluoro-ara-A and then phosphorylated intracellularly by deoxycytidine kinase to the active triphosphate, 2-fluoro-ara-ATP. This metabolite appears to act by inhibiting DNA polymerase alpha, ribonucleotide reductase and DNA primase, thus inhibiting DNA synthesis. The mechanism of action of this antimetabolite is not completely characterized and may be multi-faceted.

Clindamycin hydrochloride is the hydrated hydrochloride salt of clindamycin. Clindamycin is a semisynthetic antibiotic produced by a 7(S)-chloro-substitution of the 7(R)-hydroxyl group of the parent compound lincomycin. Clindamycin inhibits bacterial protein synthesis by binding to the 50S subunit of the ribosome. It has activity against Gram-positive aerobes and anaerobes as well as some Gram-negative anaerobes.

Lincomycin (LINCOCIN®) is an antibiotic produced by Streptomyces lincolnensis (Streptomycetaceae family). It has been used in the treatment of staphylococcal, streptococcal, and Bacteroides fragilis infections. Lincomycin (LINCOCIN®) inhibits protein synthesis in susceptible bacteria by binding to the 50S subunits of bacterial ribosomes and preventing peptide bond formation upon transcription. It is usually considered bacteriostatic, but may be bactericidal in high concentrations or when used against highly susceptible microorganisms.

Dexamethasone is an anti-inflammatory agent that is FDA approved for the treatment of many conditions, including rheumatic problems, a number of skin diseases, severe allergies, asthma, chronic obstructive lung disease, croup, brain swelling and others. Dexamethasone is a glucocorticoid agonist. Unbound dexamethasone crosses cell membranes and binds with high affinity to specific cytoplasmic glucocorticoid receptors. Adverse reactions are: Glaucoma with optic nerve damage, visual acuity and field defects; cataract formation; secondary ocular infection following suppression of host response; and perforation of the globe may occur; muscle weakness; osteoporosis and others. Aminoglutethimide may diminish adrenal suppression by corticosteroids. Macrolide antibiotics have been reported to cause a significant decrease in corticosteroid clearance.

Hydroxychloroquine possesses antimalarial properties and also exerts a beneficial effect in lupus erythematosus (chronic discoid or systemic) and acute or chronic rheumatoid arthritis. Although the exact mechanism of action is unknown, it may be based on ability of hydroxychloroquine to bind to and alter DNA. Hydroxychloroquine has also has been found to be taken up into the acidic food vacuoles of the parasite in the erythrocyte. This increases the pH of the acid vesicles, interfering with vesicle functions and possibly inhibiting phospholipid metabolism. In suppressive treatment, hydroxychloroquine inhibits the erythrocytic stage of development of plasmodia. In acute attacks of malaria, it interrupts erythrocytic schizogony of the parasite. Its ability to concentrate in parasitized erythrocytes may account for their selective toxicity against the erythrocytic stages of plasmodial infection. As an antirheumatic, hydroxychloroquine is thought to act as a mild immunosuppressant, inhibiting the production of rheumatoid factor and acute phase reactants. It also accumulates in white blood cells, stabilizing lysosomal membranes and inhibiting the activity of many enzymes, including collagenase and the proteases that cause cartilage breakdown. Hydroxychloroquine is used for the suppressive treatment and treatment of acute attacks of malaria due to Plasmodium vivax, P. malariae, P. ovale, and susceptible strains of P. falciparum. It is also indicated for the treatment of discoid and systemic lupus erythematosus, and rheumatoid arthritis.