Synthesis and characterization of

triumf.info

Synthesis and characterization of

Synthesis and characterization of

131 I-MIP-1145:

a novel therapeutic agent for treatment of

melanin-positive malignant melanoma

J Chen 1 , JF Kronauge 1 , M Friebe 2 and JW Babich 1

1

MolecularInsight Pharmaceuticals, Inc. Cambridge, MA

2

Molecular Imaging Research, Bayer Healthcare, Berlin, Germany


Malignant melanoma unmet clinical need

• 62,000 new cases of melanoma diagnosed annually in the

US

• Fastest rising incidence rate of any cancer

• Early and wide-spread metastases

• Surgery often is not effective in most cases with a

primary tumor > 3 mm in diameter,

• Stage IV patient population has 6-month life expectancy

• No current treatment has demonstrated a survival benefit


Melanin as a target for melanoma

• Between 75-90% of malignant melanomas contain melanin

• Melanin is a biopolymer containing indole units with carboxyl and

phenolic hyrdroxy groups

• Organic amines, metals, and polycyclic aromatic hydrocarbons are

capable of binding to melanin

• The physiological significance of compound-binding to normal

melanotic tissue is not clear

• May act as a protector of pigmented cells and adjacent tissues by

adsorbing potentially harmful xenobiotics or metabolic intermediates,

followed by a slow release at nontoxic levels

• Benzamide derivatives bind to melanin, and their iodinated form exhibit

high uptake in melanin-positive melanoma both in vitro and in vivo

• MIP licensed a series of benzamide derivatives from Schering-AG; lead

compound was BA-52


BA-52 licensed from Schering-AG

O

O

O

O

I

N

H

O

N

H

N


123 I-Benzamide being exploited for diagnostic

imaging of metastatic melanoma in patients

O

N

H

N

123 I

123

I-BZA

Evidenced rapid tumor wash-out

eliminated the possibility of using their

131

I-labeled counterparts in therapeutic

123 I

O

purpose.

N

H

N

123

I-BZA 2

Example of rapid tumor wash-out (%ID/g)

of 123 I-BZA in B16 melanoma bearing

C57BL/J1 mouse model. Moreau MF et al.

Nucl Med Biol. 1995,22:737-47

O

1 h 24 h 72 h

123 I

N

H

N

6.8 0.8 0.3

O

123

I-MBA


BA-52 licensed from Schering-AG

O

O

O

I

N

H

O

O

N

H

N

Tumor uptake and retention of 131 I-BA52 in

B16 melanoma bearing mice (%ID/g)

1 h 5 h 48 h

14.8 22.7 16.6

Anterior & posterior whole body images of 131 I-BA52

in melanoma patient (two different intensity

settings) at 120 h p.i


Objectives

• Develop formulation method for 131 I-benzamide (imaging

dose, ~ 100 mCi) for Phase-I clinical trial (safety and

dosimetry studies) in melanoma confirmed patients

• Submit IND application to FDA

• Develop formulation method for 131 I-benzamide (~ 3 Ci) as a

systemic radiotherapeutic agent for the treatment of melaninpositive

metastatic melanoma


Schematic 131 I-BA-52 synthesis

O

O

O

O

N

H

O

N

H

N

Precusor

TFA/Tl(TFA) 3

Electrophilic reaction

RT for 10 min

O

O

(TFA) 2 Tl

O

N

H

O

O

N

H

N

Tl(TFA) 2 -Intermediate

Na 131 I, RT, 5 min

nucleophilic substitution

O

O

O

131 I

O

N

H

O

N

H

N

131 I-labeled product


Poor chemical stability 131 I-BA52 observed

Product

O

O

131 I

N

H

O

O

N

H

N

131

I-BA52

HO

O

131 I

N

H

O

O

N

H

N

O

HO

1. Confirmed and identified the by-product via LC/MS

2. % of by-product increased over the applied radioactivity dose

3. Confirmed in two different batches of precursor (different vendors)

4. 20 mg Dioxolane decreased the by-product from 42% to 11%

5. Tested other protecting agents and different iodination methods

(Chloramine-T, KIO 3

, Tl(TFA) 3

/BF 3

.Et 2

O) without success


Low melanin targeting capacity for the

by-product (BA-52D)

1 Hour

40

30

20

10

0

BA-52

BA-52D

% Injected Dose/gram

Blood

Heart

Lungs

Liver

Spleen

Kidneys

Stomach

Lg Intestine

Sm Intestine

Sk.Muscle

Bone

Brain

Adipose

Eyes

Skin

Tumor

24 Hour

40

30

20

10

0

BA-52

BA-52D

% Injected Dose/gram

Blood

Heart

Lungs

Liver

Spleen

Kidneys

Stomach

Lg Intestine

Sm Intestine

Sk.Muscle

Bone

Brain

Adipose

Eyes

Skin

Tumor

Biod. of 131 I-labeled BA-52/BA52D in B16F10 tumor bearing mice


Screening other potential candidates at MIP

based on their stability, solubility and desirable distribution properties

O

O

131 I

N

H

N

O

131 I

O

N

H

N

N

H

O

N

H

O

F

131

I-MIP-1145

O

131

I-MIP-1144

O

O

O

O

131 I

N

H

131

I-BA52

O

O

N

H

N

Cl

O

131 I

N

H

O

N

H

131

I-MIP-1143

N


Schematic 131 I-MIP-1145/(MIP-1144/MIP-

1143/BA-52) synthesis

R

O

N

H

O

O

N

H

N

TFA/Acetic acid

Tl(TFA) 3

Electrophilic reaction

RT for 10 min

Precusor

R = Cl, OMe, or F,

for MIP-1143, MIP-

1144, or MIP-1145,

respectively.

R

(TFA) 2 Tl

O

N

H

O

O

N

H

N

Tl(TFA) 2 -Intermediate

Na 131 I, RT, 5 min

nucleophilic substitution

R

131 I

O

N

H

O

O

N

H

N

131 I-labeled product


Desirable distribution properties observed in all

four tested compounds

1 Hour

30

25

20

15

10

5

0

BA-52

MIP-1143

MIP-1144

MIP-1145

% Injected Dose/gram

Blood

Heart

Lungs

Liver

Spleen

Kidneys

Stomach

Lg Intestine

Sm Intestine

Sk.Muscle

Bone

Brain

Adipose

Eyes

Skin

Tumor

24 Hour

50

40

30

20

10

0

BA-52

MIP-1143

MIP-1144

MIP-1145

% Injected Dose/gram

Blood

Heart

Lungs

Liver

Spleen

Kidneys

Stomach

Lg Intestine

Sm Intestine

Sk.Muscle

Bone

Brain

Adipose

Eyes

Skin

Tumor

Biod. of 131 I-labeled MIP-1145/MIP-1144/MIP-1143/BA-52 in

B16F10 tumor bearing mice


Solubility difference among MIP-1145,

MIP-1144, MIP-1143

MIP-1145 MIP-1144 MIP-1143

Concentration 3 mg/mL* 3 mg/mL* 3 mg/mL*

Excipient contains

30% PEG400

30% PEG400

30% PEG400

2% Ethanol

2% Ethanol

2% Ethanol

pH of Excipient 4.3 4.3 4.3

Visual inspection Clear solution Immediate

precipitation

Immediate

precipitation

* The calculated concentration (200 X) for preclinical toxicity studies


Excipient development (1)

Effect of pH on the solubility of MIP-145

pH 4.95 pH 4.60 pH 4.35 pH 4.05

Con. MIP-1145 3 mg/mL 3 mg/mL 3 mg/mL 3 mg/mL

% of PEG400 30% 30% 30% 30%

Visual

Precipitated

Clear solution

Clear solution

Clear solution

inspection

within 3 h

over 24 h

over 24 h

over 24 h


Excipient development (2)

Adding PEG400 in Excipient (pH 4.4) enhances the solubility of MIP-1145

PEG400

6% 8% 10% 12% 6%

Con.

MIP-1145

(µg/mL)

Visual

inspection

800 (2) 800 800 800 16 (1)

precipitated

within 4 hr

precipitated

within 20 hr

clear over

1 week

Clear over

1 month

Clear over

1 month

1. Maximal chemical concentration of Rx dose of 131 I-MIP-1145 at 20 mCi/mL

2. 800 µg/mL is the concentration 50 times higher than that of Rx, to decrease the

injected amount of PEG400 in preclinical toxicity studies


MIP-1145 selected based on its superiority in

stability, solubility and desirable biodistribution

O

O

O

I

N

H

O

O

N

H

BA-52

Poor Chemical Stability

N

Cl

O

I

N

H

O

O

N

H

MIP-1143

Poor Solubility

N

O

O

I

N

H

O

O

N

H

MIP-1144

Poor Solubility

N

F

O

I

N

H

O

O

MIP-1145

N

H

N


Schematic 131 I-MIP-1145 synthesis

F

O

N

H

O

O

N

H

N

TFA/Acetic acid

Tl(TFA) 3

Electrophilic reaction

RT for 10 min

MIP-1145p

F

(TFA) 2 Tl

O

N

H

O

O

N

H

N

Intermediate

MIP-1145-Tl(TFA) 2

Na 131 I, RT, 5 min

nucleophilic substitution

F

131 I

O

N

H

O

O

N

H

N

131 I-MIP-1145


High stability for 131 I-MIP-1145

HPLC radiotrace of 250 mCi reaction solutions

250 mCi reaction

131

I-MIP-1145

RCP > 95%

25 mCi reaction

131

I-MIP-BA-52

RCP ~65%


Effect of 131 I-MIP-1145 (68 mCi/m 2 ) on SK-

MEL-3 tumor growth

Tumor Change (V/V0)

1200

1000

800

600

400

200

0

SALINE

131IMIP1145 X3

131IMIP1145 X2

131IMIP1145 X1

Dacarbazin x 3

0 10 20 30 40

Time (Days)

Percent survival

100

80

Animals euthanized if

tumor volume > 1500 mm 3

60 Saline

MIP1145 x3

40 MIP1145 x2

20

MIP1145 x1

Dacarbazin

0

0 25 50 75 100 125

Elapsed Time (Days)


Summary

• Demonstrated that the formerly selected lead compound 131 I-

BA52 is not feasible as a candidate for the project due to its

poor chemical stability.

• Selected MIP-1145 based on its chemical stability, solubility

and desirable distribution properties in tumor bearing

animals compared to MIP-1143, MIP-1144 and BA-52.

• Developed formulation method for imaging dose 131 I-MIP-

1145 (~100 mCi).

• Submitted IND application to FDA in April 2008.

• Phase-I clinical trial has been scheduled at the beginning of

October 2008


Acknowledgement

Dr. Shawn Hillier

Dr. John Marquis

Dr. John Joyal

Dr. John Barrett

Dept. of Biology, MolecularInsight Pharmaceuticals, Inc.

Steve Gallo

Nicole Lee

Dr. Eduard Luss

Dr. Yiqing Lin

Dr. Travis Besanger

Dr. Jianfeng Qi

Dr. Henry Mok.

Dept. of Development, MolecularInsight Pharmaceuticals, Inc.

More magazines by this user
Similar magazines