GOODMAN AND GILMAN'S THE
PHARMACOLOGICAL BASIS OF
THERAPEUTICS
14TH EDITION
• AUTHOR(S)LAURENCE BRUNTON;
BJORN KNOLLMANN
TEST BANK
Question 1
1⃣ Reference
Ch. 1 — Drug Discovery Pipeline — Target Identification &
Validation
2️⃣ Graduate-Level Question Stem
A biotechnology company identifies a receptor overexpressed in
resistant tumors and develops a selective antagonist. Early
clinical trials show inconsistent efficacy despite strong receptor
,binding affinity in vitro. Which factor most likely explains the
translational failure from target validation to clinical effect?
3️⃣ Options
A. Failure to achieve adequate target engagement in vivo due to
pharmacokinetic limitations
B. Excessive receptor selectivity reducing off-target activity
C. High potency leading to receptor desensitization
D. Overestimation of therapeutic index during medicinal
chemistry optimization
4⃣ Correct Answer
A
5️⃣ Rationales
Correct (A):
Target validation requires demonstrating effective target
engagement in physiological conditions. Poor bioavailability,
rapid metabolism, or limited tissue penetration can prevent
adequate in vivo drug exposure despite strong in vitro affinity,
leading to translational failure.
Incorrect (B):
High selectivity is generally desirable and unlikely alone to
cause lack of efficacy.
Incorrect (C):
Desensitization may occur with agonists but is less applicable to
,antagonist failure without evidence of pharmacodynamic
adaptation.
Incorrect (D):
Therapeutic index estimation affects safety rather than efficacy
failure.
6️⃣ Teaching Point
Target engagement in vivo is critical despite strong in vitro
potency.
7️⃣ Citation
Brunton & Knollmann (2023). Goodman & Gilman’s, 14th ed.,
Ch. 1.
Question 2️
1⃣ Reference
Ch. 1 — Phenotypic vs Target-Based Screening
2️⃣ Graduate-Level Question Stem
A research team uses phenotypic screening to identify
compounds that restore mitochondrial function in diseased
cells without knowing the molecular target. Compared with
target-based discovery, which advantage is most likely?
3️⃣ Options
, A. Increased likelihood of identifying compounds with
functional cellular efficacy
B. Guaranteed identification of mechanism of action early in
development
C. Reduced risk of off-target toxicity
D. Elimination of need for medicinal chemistry optimization
4⃣ Correct Answer
A
5️⃣ Rationales
Correct (A):
Phenotypic screening identifies compounds based on functional
outcomes, increasing chances of clinically relevant activity even
when targets are complex or unknown.
Incorrect (B):
Mechanism identification often occurs later with phenotypic
approaches.
Incorrect (C):
Off-target effects may be higher due to unknown mechanisms.
Incorrect (D):
Optimization remains necessary.
6️⃣ Teaching Point
Phenotypic screening prioritizes functional efficacy over
predefined targets.
PHARMACOLOGICAL BASIS OF
THERAPEUTICS
14TH EDITION
• AUTHOR(S)LAURENCE BRUNTON;
BJORN KNOLLMANN
TEST BANK
Question 1
1⃣ Reference
Ch. 1 — Drug Discovery Pipeline — Target Identification &
Validation
2️⃣ Graduate-Level Question Stem
A biotechnology company identifies a receptor overexpressed in
resistant tumors and develops a selective antagonist. Early
clinical trials show inconsistent efficacy despite strong receptor
,binding affinity in vitro. Which factor most likely explains the
translational failure from target validation to clinical effect?
3️⃣ Options
A. Failure to achieve adequate target engagement in vivo due to
pharmacokinetic limitations
B. Excessive receptor selectivity reducing off-target activity
C. High potency leading to receptor desensitization
D. Overestimation of therapeutic index during medicinal
chemistry optimization
4⃣ Correct Answer
A
5️⃣ Rationales
Correct (A):
Target validation requires demonstrating effective target
engagement in physiological conditions. Poor bioavailability,
rapid metabolism, or limited tissue penetration can prevent
adequate in vivo drug exposure despite strong in vitro affinity,
leading to translational failure.
Incorrect (B):
High selectivity is generally desirable and unlikely alone to
cause lack of efficacy.
Incorrect (C):
Desensitization may occur with agonists but is less applicable to
,antagonist failure without evidence of pharmacodynamic
adaptation.
Incorrect (D):
Therapeutic index estimation affects safety rather than efficacy
failure.
6️⃣ Teaching Point
Target engagement in vivo is critical despite strong in vitro
potency.
7️⃣ Citation
Brunton & Knollmann (2023). Goodman & Gilman’s, 14th ed.,
Ch. 1.
Question 2️
1⃣ Reference
Ch. 1 — Phenotypic vs Target-Based Screening
2️⃣ Graduate-Level Question Stem
A research team uses phenotypic screening to identify
compounds that restore mitochondrial function in diseased
cells without knowing the molecular target. Compared with
target-based discovery, which advantage is most likely?
3️⃣ Options
, A. Increased likelihood of identifying compounds with
functional cellular efficacy
B. Guaranteed identification of mechanism of action early in
development
C. Reduced risk of off-target toxicity
D. Elimination of need for medicinal chemistry optimization
4⃣ Correct Answer
A
5️⃣ Rationales
Correct (A):
Phenotypic screening identifies compounds based on functional
outcomes, increasing chances of clinically relevant activity even
when targets are complex or unknown.
Incorrect (B):
Mechanism identification often occurs later with phenotypic
approaches.
Incorrect (C):
Off-target effects may be higher due to unknown mechanisms.
Incorrect (D):
Optimization remains necessary.
6️⃣ Teaching Point
Phenotypic screening prioritizes functional efficacy over
predefined targets.
