Potent and selective Bruton's tyrosine kinase inhibitors: Discovery of GDC-0834

Article abstract of DOI:10.1016/j.bmcl.2015.01.032

SAR studies focused on improving the pharmacokinetic (PK) properties of the previously reported potent and selective Btk inhibitor CGI-1746 (1) resulted in the clinical candidate GDC-0834 (2), which retained the potency and selectivity of CGI-1746, but wi

Full text of DOI:10.1016/j.bmcl.2015.01.032

Accepted Manuscript
Potent and Selective Bruton’s Tyrosine Kinase Inhibitors: Discovery of
GDC-0834
Wendy B. Young, James Barbosa, Peter Blomgren, Meire C. Bremer, James J.
Crawford, Donna Dambach, Steve Gallion, Sarah Hymowitz, Jeffrey E. Kropf,
Seung H. Lee, Lichuan Liu, Joe Lubach, Jen Macaluso, Pat Maciejewski,
Brigitte Maurer, Scott A. Mitchell, Daniel F. Ortwine, Julie Di Paolo, Karin
Reif, Heleen Scheerens, Aaron Schmitt, C. Gregory Sowell, Xiaojing Wang,
Harvey Wong, Jin-Ming Xiong, Jianjun Xu, Zhongdong Zhao, Kevin S. Currie
PII:
S0960-894X(15)00044-X
http://dx.doi.org/10.1016/j.bmcl.2015.01.032
BMCL 22372
DOI:
Reference:
Bioorganic & Medicinal Chemistry Letters
To appear in:
Received Date:
Revised Date:
Accepted Date:
25 December 2014
11 January 2015
16 January 2015
Please cite this article as: Young, W.B., Barbosa, J., Blomgren, P., Bremer, M.C., Crawford, J.J., Dambach, D.,
Gallion, S., Hymowitz, S., Kropf, J.E., Lee, S.H., Liu, L., Lubach, J., Macaluso, J., Maciejewski, P., Maurer, B.,
Mitchell, S.A., Ortwine, D.F., Paolo, J.D., Reif, K., Scheerens, H., Schmitt, A., Gregory Sowell, C., Wang, X.,
Wong, H., Xiong, J-M., Xu, J., Zhao, Z., Currie, K.S., Potent and Selective Bruton’s Tyrosine Kinase Inhibitors:
Discovery of GDC-0834, Bioorganic & Medicinal Chemistry Letters (2015), doi: http://dx.doi.org/10.1016/j.bmcl.
2015.01.032
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers
we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and
review of the resulting proof before it is published in its final form. Please note that during the production process
errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Potent and Selective Bruton’s Tyrosine Kinase Inhibitors:
Discovery of GDC-0834
Wendy B. Young* a, James Barbosa b, Peter Blomgren b, Meire C. Bremer a, James J. Crawford a, Donna
Dambach a, Steve Gallion c, Sarah Hymowitz a, Jeffrey E. Kropf b, Seung H. Lee b, Lichuan Liu a, Joe
Lubach a, Jen Macaluso b, Pat Maciejewski b, Brigitte Maurer a, Scott A. Mitchell b, Daniel F. Ortwine a,
Julie Di Paolo b, Karin Reif a, Heleen Scheerens a, Aaron Schmitt b, C. Gregory Sowell a, Xiaojing Wang a,
Harvey Wong a, Jin-Ming Xiong b, Jianjun Xu b, Zhongdong Zhao b and Kevin S. Currieb
a Genentech, 1 DNA Way, South San Francisco, CA 94080
bGilead Sciences, 36 East Industrial Rd., Branford, CT 06405 (formerly CGI Pharmaceuticals)
cSt. Andrews Circle, Wallingford, CT 06492
ARTICLE INFO
ABSTRACT
Article history:
Received
Revised
Accepted
Available online
SAR studies focused on improving the pharmacokinetic (PK) properties of the previously
reported potent and selective Btk inhibitor CGI-1746 (1) resulted in the clinical candidate GDC-
0834 (2), which retained the potency and selectivity of CGI-1746, but with much improved PK
in preclinical animal models. Structure based design efforts drove this work as modifications to
1 were investigated at both the solvent exposed region as well as “H3 binding pocket.”
However, in vitro metabolic evaluation of 2 revealed a non CYP-mediated metabolic process
that was more prevalent in human than preclinical species (mouse, rat, dog, cyno), leading to a
high-level of uncertainly in predicting human pharmacokinetics. Due to its promising potency,
selectivity, and preclincial efficacy, a single dose IND was filed and 2 was taken in to a single
dose phase I trial in healthy volunteers to quickly evaluate the human pharmacokinetics. In
human, 2 was found to be highly labile at the exo-cyclic amide bond that links the
tetrahydrobenzothiophene moiety to the central aniline ring, resulting in insufficient parent drug
exposure. This information informed the back-up program and discovery of improved inhibitors.
Keywords:
Kinase inhibitor, Bruton’s tyrosine kinase, Btk,
Rheumatoid arthritis, GDC-0834, Amide hydrolysis,
single dose IND
2009 Elsevier Ltd. All rights reserved
.
Bruton’s tyrosine kinase (Btk) plays a critical role in the
development, differentiation and proliferation of B-lineage cells,
making it an attractive target for the treatment of immunological
disorders such as (rheumatoid arthritis (RA), lupus, multiple
sclerosis (MS))1-4 as well as B-cell malignancies.5 It has been
reported that 1 in 150,000 males is born with a deficiency in the
Btk gene,6 a condition called X-linked agammaglobulinemia
(XLA), manifested by lack of immunoglobulins and B cells and
first reported by Ogden Bruton in 1952.7-8 A related but less
severe X-linked immunodeficiency (xid) in mice is also known.9-
additional indications.20 The most advanced Btk inhibitor in non-
oncology indications is CC- 292, which is currently in Phase IIa
studies in RA patients.21
O
O
N
N
1 CGI-1746
N
H
N
O
N
H
O
N
10
Importantly, these xid mice are resistant to acquiring lupus11
N
O
N
N
and collagen induced arthritis.12 In addition to B cells, Btk also
plays an important role in myeloid cell inflammatory cytokine
production. 2-4 Thus, there have been significant efforts from the
pharmaceutical community with the goal of identifying Btk
inhibitors for clinical development.13-16 Of these, the most
2 GDC-0834
H
N
O
S
N
H
O
advanced
compound
in
oncology
indications
is
Figure 1 Btk inhibitors CGI-1746 (1) and GDC-0834 (2)
ibrutinib/Imbruvica®,17-18 which was recently approved for the
treatment of mantle cell lymphoma (MCL) and chronic
lymphocytic leukemia (CLL)19 and remains under evaluation in

We previously reported on the discovery of CGI-1746 (1),3, 22-
a potent, highly selective, non-covalent, reversible inhibitor of
clearance and appreciable oral bioavailability in rat (CL=6.0
mL/min/kg; F = 29%). At this point, we sought to optimize the
other parts of the molecule while maintaining the
tetrahydrobenzothiophene moiety in the H3 pocket. Thiophenes
can be problematic from a medicinal chemistry viewpoint given
that they are known to undergo bioactivation to yield reactive
metabolites,25-26 despite there being examples of marketed, oral
and chronically dosed drugs featuring this motif.27 In this case,
we reasoned that the risk was mitigated given the steric bulk (tri-
substituted thiophene) and electron withdrawing effect of the
adjacent acyl group.
23
Btk and an ideal tool molecule to investigate the biological role
that Btk signaling plays in rheumatoid arthritis and other B cell
and immune complex-mediated disorders. CGI-1746 (1) was
shown to be efficacious in several animal models of rheumatoid
arthritis.3 Although 1 was not considered to be a viable drug
candidate based on its poor ADME properties, it was an
appealing scaffold by virtue of its exquisite selectivity profile,
due to an induced ‘H3’ specificity pocket. For this reason, we
chose to pursue further development of this scaffold. In this
report, we describe the optimization of 1 to molecules with
improved drug-like properties, culminating in our first Btk
inhibitor clinical candidate, GDC-0834, 2.
Table 1. Btk activity SAR for H3 group variations.
As reported by Di Paolo, et. al.3 the CGI-1746 (1) scaffold
binds in an extended conformation to Btk as illustrated in Figure
2. This binding event induces a conformational change in Btk
relative to the Apo structure (pdb 3P08) resulting in a Src-like
inactive conformation of the kinase domain. This includes
rearrangement of Y551 by ~18Å from an extended, solvent
exposed position to a buried conformation. The t-butyl phenyl
group of CGI-1746 (1) binds into a lipophilic pocket (termed the
H3 pocket). The pyrazinone HN-C-C-CO binds to the hinge
M477 while the morpholine-amide extends into solvent.
IC50 (uM)a
Compound ID
R
Btka
4.60
CD86a
--
3
4
5
0.86
--
--
0.225
CGI-1746 (1)
0.008
0.15
6
7
8
9
0.23
0.04
0.11
0.03
0.41
0.08
--
0.58
10
11
0.15
0.09
2.8
1.1
Figure 2 X-ray crystal structure of CG1-1746 (1) bound in Btk (pdb
code 3OCS3) illustrating the location of key regions of Btk and
important interactions with CGI-1746.
Our initial SAR studies evaluated the effect of varying the
substitution on the terminal phenyl ring of 1 as well as replacing
this ring with alternate arenes on binding interactions in the H3
pocket. Over 100 analogs were synthesized with representative
examples shown in Table 1. We assessed inhibition against the
target enzyme (Btk) as well as the downstream effect on anti-
IgM-stimulated cell surface CD86 expression. Since the binding
pocket is relatively confined and comprised of a series of
lipophilic residues, only a small subset of these analogs bound
well. For instance, the unsubstituted phenyl 3 had poor binding
affinity with an IC50 of 4.6 uM but addition of para subsitutents,
as in 1 and 4-11, all offered increased potency as compared to 3.
The thiophene isostere, 12, was fairly potent but still inferior to 1.
Indeed, the original lead CGI-1746 (1), possessing a para-t-butyl
group, was the best from this initial series. Unfortunately, this
compound suffered from poor pharmacokinetic properties in rat
(clearance (CL) = 87 mL/min/kg; oral bioavailability (F%)
<5%), so an early goal was to improve the oral exposure of this
compound. Adding polarity to the aryl ring, as in examples 13-
16, caused a decrease in binding affinity in all cases, presumably
due to clashes with lipophilic residues in the binding pocket. We
were able to identify tetrahydrobenzothiophene 17 that did
maintain equivalent potency to 1, although related analogs 18-21
failed to offer any improvement in affinity. Importantly, from
this set, 17, represented the only example with improved
12
13
0.06
0.27
0.49
3.7
14
15
16
0.05
0.13
0.07
--
3.5
0.89
17
18
0.008
0.15
0.23
1.3
19
20
21
0.34
0.19
0.03
--
--
--
a) assay conditions in supplementary materials

Table 2 SAR for H2 group variations
potency difference was observed between the enantiomers in
vitro, and thus compound 2 was selected for further studies and
ultimately was nominated as the clinical candidate, GDC-0834
(2).
GDC-0834 (2) inhibits Btk in vitro with an IC50 of 0.006 uM
and has an EC50 of 0.060 uM in the cell based CD86 assay. In
human whole blood, 2 demonstrated potent inhibition of both
anti-IgE stimulated CD63 expression (basophils) and anti-IgD
stimulated CD69 expression (B-cells) with EC50’s of 0.35 and
0.38 uM, respectively (Table 3). Additionally, GDC-0834 (2)
has shown efficacy in a rat collagen-induced arthritis (CIA)
model, causing a dose-dependent decrease of ankle swelling and
reduction of morphologic pathology.28
Rat
CLa / Fb
IC50 uM
Btk CD86
Compound
ID
R
17
0.008
0.23
6.0 / 29%
22
23
0.23
--
--
Table 3 Human Potency of GDC-0834 (2)
0.050
5.0
9.2 / 53%
Enzyme
IC50
B-cell
EC50
whole blood
EC50
24
25
0.49
0.65
--
--
--
basophils
B-cell
CD69
Btk
CD86
5.4 / 37%
CD63
0.006 uM
0.06 uM
0.35 uM
0.38 uM
26
27
0.043
0.21
1.1
--
--
--
Importantly, GDC-0834 (2) retained the same selectivity
profile as CG1-1746 (1) demonstrating excellent biochemical
selectivity against a panel of 331 kinases (Figure 3). The sole
exception was the TEC-family kinase Bmx29 for which there was
only a 3-fold preference for Btk based on biochemical IC50
values. Additionally, GDC-0834 (2) had minimal to no off-target
receptor activity when screened against a panel of 30 targets (all
< 35% at 10 uM), minimal inhibition of the hERG channel (27%
at 10 uM), and was negative in a gene-tox profile Ames
(TA98/100 strains; +/- S9) and micronucleus tests (+/- S9).
28
29
0.054
0.01
1.3
--
111 / <
5%
0.06
30
31
0.06
0.05
0.02
0.80
23.9
0.16
--
--
32
2
11 / 41%
0.006
0.06
4.4 / 35%
b
aclearance (CL)=mL/min/kg oral bioavailability (F)
Our next efforts focused on determining the scope of
moieties that would be tolerated in the partially solvent-exposed
H2 region. Over 300 compounds were prepared in this endeavor,
with a range of these shown in Table 2. Inhibitors with
unsubstituted mono aryl groups 22-25 lost significant potency.
Bicyclic analogs such as 26-28 likewise failed to match the
Figure 3 Kinase selectivity profile of GDC-0834 (2) vs. a panel
of 331 kinases at 1 uM concentration.
enzyme potency of CGI-1746 (1).
Ultimately, extending
moieties from the para position of the aryl ring appeared to offer
the best balance of biochemical and cellular potency while
retaining acceptable pharmacokinetic properties in rat. N-Me-
piperidine-containing example 29 proved to be highly potent but
suffered from high in vivo CL in rat (111 mL/min/kg). Lower in
vivo CL was found with the dimethyl-3-oxopiperazin-2-yl
enantiomers, 32 and 2. The absolute configuration of 2 was
determined by a single crystal X-ray. Accordingly, 32 was then
assigned as the opposite enantiomer. Between 2 and 32, a 3-fold
We obtained a 1.95 Å resolution crystal structure of GDC-
0834 (2) in complex with Btk,30 confirming a near-identical
binding configuration to CGI-1746 (Figure 4).
The
conformation of the Btk kinase domain is also very similar
between the two structures with an r.m.s.d. of 0.12 Å2 over 1838
atoms. The tetrahydrobenzothiophene moiety binds in the H3
pocket created by residues L542, V546, S543, and Y551 of the
fully ordered activation loop. The side chains of the Gly-rich
loop residues Q412 and F413, the backbone of residues T410 and

G411, as well as the catalytic loop residues D521 and N526, and
the DFG residue D539 also contribute to the specificity. The
amide linking the central aryl to the tetrahydrobenzothiophene
makes interactions identical to those observed in the CGI-1746-
Btk co-crystal structure, including a non-classical hydrogen bond
to K430. The pyrazinone HN-C-C-CO binds to the hinge M477
while the dimethyl-3-oxopiperazin-2-yl extends into the solvent
region where it can likely access more than one conformation.
The original synthesis of GDC-0834 (2) has been previously
reported.31 Here, in Scheme 1 (with full details in Supplemental
Material), we outline an improved method for larger scale
production. Carboxylic acid I was transformed to the acid
chloride II via the action of oxalyl chloride in DCM. Thereafter,
reaction of acid chloride II with amino-boronate III afforded IV
in 80% yield from I. Aniline V (single stereoisomer) underwent
coupling with dibromopyrazinone VI to afford VII. Final
coupling of bromo-pyrazine VII and boronate IV catalyzed by
tetrakis(triphenylphosphine)palladium provided GDC-0834 (2).
GDC-0834 (2) exhibited low clearance in rats, moderate
clearance in mice and dogs, and high clearance in cynomologus
monkeys (Table 4). Oral bioavailability was acceptable in all
species and showed that oral exposures were achievable
following crystalline suspension. The rat oral bioavailability of
crystalline freebase suspension was slightly lower compared to
solution, presumably due to low solubility limiting its oral
absorption (mp = 212 ºC; solubility = 0.007 mg/mL in fasted-
state simulated intestinal fluid pH 6.8, 37 ºC). However, data
from dogs, suggested otherwise since oral bioavailablity was
similar when comparing solution and crystalline freebase
suspension dosing.
In vitro studies in liver microsomes and hepatocytes were
run with GDC-0834 (2) in order to aid in an estimation of human
clearance. Of note, the in vitro to in vivo correlation was variable
among the preclinical species, and was particularly poor in the rat
which suggested a large overestimation of in vivo clearance by in
vitro methodologies (Table 4). In vitro liver microsome studies
were run in the presence and absence of NADPH in order to
characterize the extent of non cyp-mediated metabolism that had
not previously been observed. The in vitro clearance of 2 in the
absence of NADPH was identical to that measured in the
presence of NADPH in human microsomes, suggesting
significant non cyp-mediated metabolism. Non CYP-mediated
metabolism was less pronounced in other species (mouse, rat,
Figure 4: a) Crystal structure of GDC-0834 (2) in Btk; b)
Comparison of the binding modes of CGI-1746 and GDC-0834.
Scheme 1: Synthesis of GDC-0834
dog, and cyno).
As previously reported24, the clearance of
GDC-0834 (2) in human was predicted to be low to moderate
when projected from preclinical species using allometric scaling
of in vivo data, but high from human microsomes and
hepatocytes (CLhep 19, 19 mL/min/kg, respectively). Overall, the
predicted human clearance ranged from low to high.
Table 4 GDC-0834 Preclinical Data
Preclinical DMPK Data
Clearance mL/min/kg
in vitro
Oral
Bioavailability
sol.a (susp.)b
species
in
Liver
Liver
vivo
microsomes
hepatocytes
(+/-NADPH)
19 / 18
79 / 25
39 / 8
human
mouse
rat
19
63
25
19
32
18%a
43
5
35%a (16%)b
35%c (32%)b
dog
28 / 7
14
cyno
36 / 2
33
16%c
aSolution in 20% (v/v) Cremophor EL, 10% (v/v) ethanol in water;
bSuspension of crystalline freebase in 0.5% (w/v) methylcellulose,
c
0.2% (w/v) polysorbate 80 in water; Solution in 60% polyethylene
glycol 400 in water

There was little confidence in our human clearance
predictions for GDC-0834 since there appeared to be species
differences in the metabolic route of elimination with GDC-0834
being metabolized primarily by non-CYP mediated pathways. At
the time, there was considerably less known about the in vitro to
in vivo correlation of non-CYP mediated metabolism compared
to CYP metabolism.24 Some reassurance was gained when 2 was
studied in PXB chimeric mice with humanized livers and low
clearance was observed.24 Due to the risks associated with the
projected human PK of this molecule, we chose to file a single
dose investigational new drug (IND) application.32 A single dose
IND allowed us to expedite the understanding of the disposition
of GDC-0834 (2) in human while reducing initial risk and cost.
Furthermore, these human data would serve to inform the back-
up program.
Under the single dose IND, healthy volunteers received GDC-
0834 (2) orally (35 mg or 105 mg) and plasma concentrations
were monitored. Parent compound 2 was not observed in
plasma, rather only the product of amide hydrolysis M1 (Figure
5) and, in turn, its metabolites were detected. We later learned,
perhaps surprisingly, that aldehyde oxidase (AO) and/or carboxy
esterase, is the enzyme most likely responsible for the amide
cleavage.33 AO is known to have higher expression in human as
compared to dog, rat, mouse and cyno. In light of this, we
focused our subsequent efforts on addressing this metabolic
pathway with the goal of identifying a compound predicted to
have improved metabolic stability in human.
References and notes
1.
2.
3.
Satterthwaite, A. B. Witte, O. N. Immunol. Rev. 2000, 175, 120.
Brunne, R. C.; Muëller, B.; Wirth, T. Histol. Histopathol. 2005, 20, 945.
Di Paolo, J. A.; Huang, T.; Balazs, M.; Barbosa, J.; Barck, K. H.;
Bravo, B. J.; Carano, R. A.; Darrow, J.; Davies, D. R.; DeForge, L. E.;
Diehl, L.; Ferrando, R.; Gallion, S. L.; Giannetti, A. M.; Gribling, P.;
Hurez, V.; Hymowitz, S. G.; Jones, R.; Kropf, J. E.; Lee, W. P.;
Maciejewski, P. M.; Mitchell, S. A.; Rong, H.; Staker, B. L.; Whitney,
J. A.; Yeh, S.; Young, W. B.; Yu, C.; Zhang, J.; Reif, K.; Currie, K.
Nat. Chem. Biol. 2011, 7, 41.
4.
5.
6.
Puri, K. D., Di Paolo, J.; Gold, M. R. Int. Rev. Immunol. 2013, 32, 397.
Uckun FM, Qazi S. Expert Opin Ther Pat. 2010, 20, 1457.
Smith, C. I. E.; Islam, K.B.; Vorechovsky, I.; Olerup, O.; Wallin, E.;
Rabbani, H.; Baskin, B.; Hammarstrom, L. Immunol. Rev. 1994, 138,
159.
7.
8.
Bruton, O. C. Pediatrics 1952, 9, 722.
Howard, V.; Greene, J.M.; Pahwa, S.; Winkelstein, J. A.; Boyle, J. M.;
Kocak, M.; Conley, M. E. Clin. Immunol.. 2006, 118, 201.
Satterthwaite, A.B.; Witte, O.N. Immunol. Rev. 2000, 175, 120.
9.
10. Tsukada, S., Rawlings, D.J.; Witte, O.N. 1994 Curr. Opin. Immunol. 6,
623.
11. Steinberg, D. D. J. Clinic. Invest. 1982, 70, 587.
12. Jansson, L.; Holmdahl, R. Clin. Exp. Immunol. 1993, 94, 459.
13. Lou, Y.; Owens, T. D.; Kuglstatter, A.; Kondru, R. K.; Goldstein, D. M.
J. Med. Chem. 2012, 55, 4539.
14. Pan, Z. Drug News Perspect. 2008, 21, 357.
15. Rokosz, L. L.; Beasley, J. R.; Carroll, C. D.; Lin, T.; Zhao, J.; Appell,
K. C.; Webb, M. L. Expert Opin. Ther. Targets 2008, 12, 883.
16. Uckun, F. M.; Tibbles, H. E.; Vassilev, A. O. Med. Chem. 2007, 7, 624.
17. Chavez, J. C.; Sahakian, E.; Pinilla-Ibarz, J. Core Evidence, 2013, 8, 37.
18. Akinleye, A.; Chen, Y. I.; Mukhi, N.; Song, Y.; Liu, D. JJ. Hematol.
Oncol. 2013, 6, 59.
19. http://www.fda.gov/Drugs/InformationOnDrugs/ApprovedDrugs/ucm37
4857.htm
20. http://www.clinicaltrial.gov/ct2/results?term=ibrutinib&Search=Search
21. http://clinicaltrials.gov/show/NCT01975610
22. Brittelli, D. R. et al. WO/2006/099075 2006.
23. Currie, K. S. Brussels, Belgium; 2010 EFMC 21st International
Symposium on Medicinal Chemistry, Brussels, Belgium
24. Liu, L.; Halladay, J.; Shin, Y.; Wong, S.; Coraggio, M.; La, H.;
Baumgardner, M.; Le, H.; Gopaul, S.; Boggs, J.; Kuebler, P.; Davis, J.;
Liao, C.; Lubach, J.; Deese, A.; Sowell, G.; Currie, K.; Young, W.;
Khojasteh, C.; Hop, C.; Wong, H. Drug Metab. Dispos., 2011, 39,
1840-9.
25. Kalgutkar; A. S; Gardner, I; Obach, R. S.; Shaffer, C. L.; Callegari, E.;
Henne, K. R.; Mutlib, A. E.; Dalvie, D. K.; Lee, J. S.; Nakai,
Y; O'Donnell, J. P.; Boer. J.; Harriman, S. P. Curr Drug Metab. 2005, 3,
161.
Figure 5 Cleavage of 2 in human to generate aniline metabolite
M2
In conclusion, GDC-0834, a highly potent and selective Btk
inhibitor with acceptable preclinical in vivo profile was identified
as the first clinical candidate from this series. Due to the large
range of human in vivo predictions based on varying metabolism
in preclinical species, we chose to take GDC-0834 into a single
dose phase 1 healthy volunteer trial to rapidly learn the human
PK profile and to inform potential back-up efforts. In human, 2,
was found to be highly labile at the amide bond linking the H3-
moeity to the aniline ring, with this being a particular liability in
human. Subsequent efforts have shown that this metabolic
liability can be minimized by substitution of the aniline ring,
through steric blockage of amide hydrolysis or cyclization of the
amide –NH onto the H3-group. Our efforts in these areas will be
described in upcoming communications.
26. Rademacher, P. M.; Woods, C. M.; Huang, Q.; Szklarz, G. D.; Nelson,
S. D. Chem. Res. in Toxicol., 2012, 25, 895.
27. Recent example: InvokanaTM (canaglifozia)
http://www.invokanahcp.com/prescribing-information.pdf
28. Liu, L.; Di Paolo, J.; Barbosa, J.; Rong, H.; Reif, K.; Wong, H. J.
Pharmacol. Exp. Ther. 2011, 338, 154.
29. Muckelbauer, J.; Sack, J. S.; Ahmed, N.; Burke, B.; Chang, C. Y.; Gao,
M.; Tino, J.; Xie, D.; Tebben, A. Chem Biol. Drug Des. 2011, 78, 793.
30. See the Supplementary data for the experimental details associated with
the co-crystal structure of BTK with GDC-834. The coordinates and
structure factors have been deposited with the protein data bank and
assigned the accession code 4OTF.
31. Blomgren, P.A. et.al. U.S. Patent 7,8884,108.
32. http://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryI
nformation/Guidances/ucm078933.pdf
33. Sodhi, J.; Wong, S.; Liu, L.; Khojasteh, S. C.; Hop, C. E. C. A; Barr, J.
T.; Jones, J. P.; Kirkpatrick D. S.; Halladay, J. Drug Metab. Dispos.,
submitted.
Acknowledgments
We thank the Btk team members at Gilead (formerly CGI
Pharmaceuticals Inc.), Genentech, Chem Partners, and AMRI for
their contributions in generating the data for this manuscript.
Use of the Advanced Light Source is supported by the U.S.
Department of Energy under Contract No. DE-AC02-
05CH11231.

.
Graphical Abstract
Potent and Selective Bruton’s Tyrosine Kinase
Inhibitors: Discovery of GDC-0834
Leave this area blank for abstract info.
Wendy B. Young, James Barbosa, Peter Blomgren, Meire C. Bremer, James J. Crawford, Donna Dambach, Steve Gallion,
Sarah Hymowitz, Jeffrey E. Kropf, Seung H. Lee, Lichuan Liu, Joe Lubach, Jen Macaluso, Pat Maciejewski, Brigitte
Maurer, Scott A. Mitchell, Daniel F. Ortwine, Julie Di Paolo, Karin Reif, Heleen Scheerens, Aaron Schmitt, C. Gregory
Sowell, Xiaojing Wang, Harvey Wong, Jin-Ming Xiong, Jianjun Xu, Zhongdong Zhao and Kevin S. Currie