Rimiducid (AP-1903) is a lipid-permeable analogue of tacrolimus with homodimerizing activity. As dimerizer agent, it acts by cross-linking the FKBP domains, initiating Fas signaling and hence apoptosis. Specifically, it homodimerizes an analog of human protein FKBP12 (Fv) which contains a single acid substitution (Phe36Val) so that AP1903 binds to wild-type FKBP12 with 1000-fold lower affinity. Rimiducid is used to homodimerize the Fv-containing drug-binding domains of genetically engineered receptors such as the iCD40 receptor of the autologous dendritic cell vaccine BP-GMAX-CD1, resulting in receptor activation.

Physicochemical Properties

Molecular Formula	C78H98N4O20
Molecular Weight	1411.63
Exact Mass	1410.677
CAS #	195514-63-7
PubChem CID	16135625
Appearance	White to light yellow solid powder
Density	1.2±0.1 g/cm3
Boiling Point	1307.5±65.0 °C at 760 mmHg
Flash Point	744.5±34.3 °C
Vapour Pressure	0.0±0.3 mmHg at 25°C
Index of Refraction	1.566
LogP	10.39
Hydrogen Bond Donor Count	2
Hydrogen Bond Acceptor Count	20
Rotatable Bond Count	39
Heavy Atom Count	102
Complexity	2330
Defined Atom Stereocenter Count	6
SMILES	CC[C@@H](C1=CC(=C(C(=C1)OC)OC)OC)C(=O)N2CCCC[C@H]2C(=O)O[C@H](CCC3=CC(=C(C=C3)OC)OC)C4=CC(=CC=C4)OCC(=O)NCCNC(=O)COC5=CC=CC(=C5)[C@@H](CCC6=CC(=C(C=C6)OC)OC)OC(=O)[C@@H]7CCCCN7C(=O)[C@@H](CC)C8=CC(=C(C(=C8)OC)OC)OC
InChi Key	GQLCLPLEEOUJQC-WFMNNBDOSA-N
InChi Code	InChI=1S/C78H98N4O20/c1-13-57(53-43-67(93-7)73(97-11)68(44-53)94-8)75(85)81-37-17-15-25-59(81)77(87)101-61(31-27-49-29-33-63(89-3)65(39-49)91-5)51-21-19-23-55(41-51)99-47-71(83)79-35-36-80-72(84)48-100-56-24-20-22-52(42-56)62(32-28-50-30-34-64(90-4)66(40-50)92-6)102-78(88)60-26-16-18-38-82(60)76(86)58(14-2)54-45-69(95-9)74(98-12)70(46-54)96-10/h19-24,29-30,33-34,39-46,57-62H,13-18,25-28,31-32,35-38,47-48H2,1-12H3,(H,79,83)(H,80,84)/t57-,58-,59+,60+,61+,62+/m0/s1
Chemical Name	(S,2R,2'R)-(1R,1'R)-((((ethane-1,2-diylbis(azanediyl))bis(2-oxoethane-2,1-diyl))bis(oxy))bis(3,1-phenylene))bis(3-(3,4-dimethoxyphenyl)propane-1,1-diyl) bis(1-((S)-2-(3,4,5-trimethoxyphenyl)butanoyl)piperidine-2-carboxylate)
Synonyms	AP-1903 Rimiducid AP 1903 AP1903
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: This product is not stable in solution, please use freshly prepared working solution for optimal results.
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	EC50: 0.1 nM (FKBP, in HT1080 cells)[1] Fas receptor[1]
ln Vitro	Rimiducid (AP1903) causes significant and dose-dependent apoptosis of modified cells in culture, with an EC50 of around 0.1 nM [1]. Maximum killing occurs in the presence of 3 to 10 nM Rimiducid (AP1903), with an IC50 of around 0.2 nM. LV'VFas-transduced T cells (upper panel) with high levels of CD25 were removed with an efficiency of 66%±7.5% (n=10). After CD25 expression recovered to baseline levels, Rimiducid therapy resulted in 63%±4.7% (n=9) cell death [2].
ln Vivo	Serum human growth hormone levels are reduced in a dosage-dependent manner by fumiducid (AP1903; iv, 0.01, 0.1, 1, 10, and 100 mg/kg); the half-maximum efficacious dose is 0.4 ± 0.1 mg/kg [1].
Cell Assay	Cloned HT1080 cell lines (ATCC CCL-121) retrovirally transduced with Fas constructs are prepared. Cell viability after overnight incubation with Rimiducid (0.01 nM, 0.1 nM, 1 nM, 10 nM, 100 nM, 1000 nM) is measured by Alamar Blue assay[1]. For annexin V assays, sorted LV′VFas-transduced T cells (2×106 cells/mL) are incubated with 10 nM Rimiducid. At the indicated time, an aliquot of 2×105 cells is taken, stained with annexin V-fluorescein isothiocyanate, and analyzed by flow cytometry[2].
References	[1]. Redesigning an FKBP-ligand interface to generate chemical dimerizers with novel specificity. Proc Natl Acad Sci U S A. 1998 Sep 1;95(18):10437-42. [2]. A Fas-based suicide switch in human T cells for the treatment of graft-versus-host disease. Blood. 2001 Mar 1;97(5):1249-57.
Additional Infomation	Rimiducid is a lipid-permeable tacrolimus analogue and a protein dimerizer. It was designed to overcome limitations of current cellular immunotherapies used for cancer and other blood disorders by enhancing the control of the immune cell activity and function. When administered via chemically-inducible dimerization (CID) technologies, rimiducid binds to switch proteins and dimerizes them, triggering downstream signaling cascade. The combination use of rimiducid with immunotherapies for enhanced therapeutic effectiveness is currently under investigation. Rimiducid is a lipid-permeable tacrolimus analogue with homodimerizing activity. Dimerizer drug AP1903 homodimerizes an analogue of human protein FKBP12 (Fv) which contains a single acid substitution (Phe36Val) so that AP1903 binds to wild-type FKBP12 with 1000-fold lower affinity. This agent is used to homodimerize the Fv-containing drug-binding domains of genetically engineered receptors such as the iCD40 receptor of the autologous dendritic cell vaccine BP-GMAX-CD1, resulting in receptor activation. Drug Indication Investigated for use/treatment in bone marrow transplant and graft versus host disease. Treatment of graft versus host disease Mechanism of Action Rimiducid binds to a drug binding domain derived from human FK506-binding protein which is present on a modified form of inducible caspase-9. This binding results in dimerization and subsequent activation of caspase-9. This system was designed to function as a "safety switch" in CAR T-cell therapy used in hematological cancers. Retroviral vectors used in production of these modified cells preferentially integrate this gene nearby promoters associated with T-cell activation. This results in higher expression of the modified inducible caspase-9 product in activated T-cells. In practice, this allows for specific targeting of these active T-cells by rimiducid which results in a decrease in circulating cell numbers of over 90% in the setting of graft versus host disease. This specificity spares non-alloreactive T-cells and allows for successful reconstitution of the transplanted immune system from these cells.[24753538] Additionally, these non-alloreactive cells retain their sensitivity to rimiducid. Pharmacodynamics Rimiducis is used to activate inducible caspase-9 produced by a modified gene included in some CAR T-cell therapies. This activation produces rapid induction of apoptosis in activated modified T-cells and resolution of the signs and symptoms of graft versus host disease within 24 hours.

Solubility Data

Solubility (In Vitro)

DMSO : ~100 mg/mL (~70.84 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (1.77 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly. Solubility in Formulation 2: 2 mg/mL (1.42 mM) in 2% DMSO 98% Corn Oil (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	0.7084 mL	3.5420 mL	7.0840 mL
	5 mM	0.1417 mL	0.7084 mL	1.4168 mL
	10 mM	0.0708 mL	0.3542 mL	0.7084 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.