# Presentation: 289278

## The NCI Approach To  Drug Development

- Edward A. Sausville, M.D., Ph.D.
- Developmental Therapeutics Program
- National Cancer Institute

## Goals Of Preclinical Drug Studies

-   Discovery of “lead structures”
-   “Refinement”: chemistry, pharmacology, efficacy 				=“Early” development
-   Late development: formulation, dose form, toxicology

*Scientific framework*

## Goals Of Preclinical Drug Studies

-  IND = “Investigational New Drug” application
- = approval by FDA to conduct human studies;
- main criterion : SAFETY AND LIKELY REVERSIBLE TOXICITY  = allows *start* of Phase I trials
-  NDA = “New Drug Application”
- = basis for sale to public;
- main criteria: SAFETY AND SOME MEASURE OF EFFICACY = *result* of Phase II/III trials

*Regulatory framework*

## Cancer Drugs:How Do We Know We Have A Winner?

- - PHASE III  CLINICAL TRIAL
- 	= WINNER

- - PHASE II
- 	= POTENTIAL
- 	   WINNER

**; Time?**

- - PRECLINICAL MODEL
- 	(e.g., mouse or rat)

**Cytotoxic**

## Cancer Drugs:  How To Pick A Winner?

- “VALIDATED” CANCER TARGETS

- DNA
- Alkylators
- Antimetabolites
- Topo I / II
- Tubulin
- Receptors
- Nuclear
- Cell Surface (Immune?)
- Oncogene Proteins (2001: AT LAST!)

## “Empirical” Drug Discovery

## Problems With Empirical Models

-   Lack of predictive power *in vivo*
-   Poor correlation of non-human with human pharmacology
-   Divorced from biology
-   Inefficient: many compounds screened;
- 	developed, but have “late” = clinical trials outcome
- 	at Phase III to define “validation” of compound action

## KRN5500

- Cell Membrane

## Effect Of KRN5500 On Colo-205 Athymic Mouse Xenografts

## KRN5500 Plasma Concentrations On Effective Schedule(20 mg/kg/d) In Mice

**KRN5500 Plasma Concentrations On Effective Schedule(20 mg/kg/d) In Mice**

- Plasma Concentration (M)

- Time (days)

## Summary Of KRN5500 Phase I

-   26 patients as IV once per day over 5 days
-   Dose limiting toxicity = interstitial pneumonitis
-   MTD = 2.9 mg/M2/d x 5
-   Achieve only 0.75 - 1 M at 3.7 mg/M2/d x 5
-   4/6 patients with >25% incr Cmax have

- 	grade 4 toxicity

*Data of J. P. Eder, DFCI*

## In Vivo i.e., Intact Animal Tumor Models

-   The information received depends on the question asked:
- not all models are appropriate for all questions
-   Drugs need different types of models at different times
- in their “discovery / development” life cycle
-  “Pharmacology” models to qualify compound
-  “Efficacy” models to define potential for biologic effect
-   Target driven
-   Target unselected
-  “Biology” models to confirm ONLY the target
- or molecular events related to target are affected

##  In Vivo Activity vs Clinical Activity (39 Agents)

## “Rational” Drug Discovery

- PHARMACOLOGY
- (to affect target)

- CHEMISTRY

- MOLECULAR TARGET SCREEN

- Biochemical
- Engineered cell
- Animal (yeast/worm/fish)

## How To “Build” A Cancer Cell

-   Imbalance of Genes Regulating Cell Death
-   Immortality / Telomerase
-   Angiogenesis / Invasion Phenotype

**How To “Build” A Cancer Cell**

**Cancer cells possess defined “families” of lesions**
**with common outcomes**

**G****0**

- - “Oncogenes” turned on
- - “Suppressor genes” turned off
- -  Mimic Growth Regulatory
- 	“Signal Transduction”

- Tumor Size

*(After Varmus, Bishop, Weinberg, Croce, Folkman, Hanahan ... etc.)*

## Molecular Target Definition - How To?

- *  “Positive” selection from tumor DNA              Active oncogenes
-         (signal transduction)
- *  Tumor gene expression profiling (CGAP)
- * Binding partners  (geldanamycin, rapamycin, fumagillin)
- * Computational algorithm  (molecule            target)
- *  Cell metabolism / Cell cycle effects
- *  Suggest single targets               Inefficient
- *  Libraries of molecules and precisely defined organisms

**Molecular Target Definition - How To?**

-   **BIOLOGY:**
**  “ ****RETROFIT” ACTIVE MOLECULES:**
**  “****CLASSICAL:”**
**  ****CHEMICAL GENETICS:**

- - COMPARE
- - Cluster analysis

## bcr-abl As Target: Rationale

-   Apparently pathogenetic in t9:Q22 (Ph+) CML/ALL
-   Absence in normal tissues
-   Modulate signal transduction events downstream

- Maintenance of chronic phase
- Adjunct to bone marrow transplantation

## bcr-abl  Fusion Protein

- bcr

- SH2

- SH2

- V

- SH2/SH3

- kinase

- NT

- DNA

- Actin

- bcr

- autophosphorylation

- Phosphorylation of
- other substances

*McWhirter JR, *EMBO* 12:1533, 1993*

## Example Of “Rational” Approach:bcr-abl directed agents

- erbstatin

- lavendustin

- piceatannol

- AG957

- AG1112

**CGP 57148B = STI571**

- Natural
- product
- empiric lead
- 1st generation
- synthetic
- 2nd generation
- synthetic;
- in clinic

## STI571:An Oral In Vivo Bcr-abl Kinase Inhibitor

**STI571:****An Oral *****In Vivo***** Bcr-abl Kinase Inhibitor**

**Tyr phosphorylation *****in vivo***

*le Coutre et al, JNCI 91:163, 1999*

**Antitumor activity *****in vivo***

- (hrs)

- (days)

- (days)

## Efficacy And Safety Of A Specific Inhibitor Of The Bcr-abl Tyrosine Kinase In Chronic Myeloid Leukemia

**Efficacy And Safety Of A Specific Inhibitor Of The Bcr-abl Tyrosine Kinase In Chronic Myeloid Leukemia**

- BRIAN J.DRUKER,M.D.,MOSHE TALPAZ,M.D.,DEBRA J.RESTA,R.N.,BIN PENG,PH.D.,
- ELISABETH BUCHDUNGER,PH.D.,JOHN M.FORD,M.D.,NICHOLAS B.LYDON,PH.D.,HAGOP KANTARJIAN,M.D.,
- RENAUD CAPDEVILLE,M.D.,SAYURI OHNO-JONES,B.S.,AND CHARLES L.SAWYERS,M.D.

- % in Metaphase

- Ph Chromosome + Cells

- White Cell Count

- (cells x 10-3 / mm3)

- Duration of Treatment with STI571 (Days)

## NCI Drug Discovery

-  Aids to find targets  / link targets with drugs
- -Cancer Genome Anatomy Project (CGAP)
- -Developmental Therapeutics Program *In Vitro* Drug Screen
-  Where the target is known: build its assessment into the selection and development of a compound: e.g., 17-allylamino 17-demethoxy geldanamycin (17-AAG)
-  Where the target is unknown, define it or a proximal indicator of effect in parallel with conventional development path: e.g., UCN-01 protein kinase inhibitor

*A Marriage Of Empirical *And* Rational Opportunities *

## Cancer Genome Anatomy Project: PROCESS

## Gene Expression:  The Cell’s Fingerprint

- with the amount of gene products produced for each, yields a
- powerful "fingerprint". Comparing the fingerprints of a normal versus
- a cancer cell will highlight genes that by their suspicious absence or
- presence (such as Gene H ) deserve further scientific scrutiny to
- determine whether such suspects play a role in cancer, or can be
- exploited in a test for early detection.

**Gene Expression:  The Cell’s Fingerprint**

- http://cgap.nci.nih.gov

## NCI In Vitro Drug Screen

## All Cell Lines

- Log10 of Sample Concentration (Molar)

- Percentage Growth

- 100

- 50

- 0

- -50

- -100

- -9

- -8

- -7

- -6

- -5

- -4

## Pattern Recognition Algorithm:COMPARE

-   Goal:  COMPARE degree of similarity of a new
- 	compound to standard agents
-   Calculate mean GI50, TGI or LC50
-   Display behavior of particular cell line as deflection
- 	from mean
-   Calculate Pearson correlation coefficient:

***1 = identity ; 0 = no correlation***

## Agents With Similar Mechanisms HaveSimilar Mean Graphs

- Taxol

- Halichondrin B

- Daunorubicin
- Topoisomerase II

- Leukemia
- NSCLC
- Small Cell Lung
- Colon
- CNS
- Melanoma
- Ovarian
- Renal

**Agents With Similar Mechanisms Have****Similar Mean Graphs**

- Tubulin

## Drug Target ClusteringsReveal Clues To Mechanism

*Nature Genetics 24: 236, 2000; http://dtp.nci.nih.gov*

## Geldanamycin Structure

**Geldanamycin Structure**

## Benzoquinoid AnsamycinsInitial Cell Pharmacology 

- Benzoquinoid AnsamycinsInitial Cell Pharmacology

**Reduce levels or inhibit transformation by a large number of PTKs:  src, yes, fps, erbB1, lck**
**e.g., 17AAG decrease erbB2 under conditions where overall transcription/translation little affected**

***(Miller et al, Cancer Res 54: 2724, 1994)***

**150**
**100**
**50**
**0**

**MDA MB 453**

**%**** Control**

**p185 Protein**
**p185 PY**

**Hours**

## DTP, NCI In Vivo EvaluationOf Geldanamycin In PC3 Prostate CA

- Route of administration – i.p.

***Conclude:***  	Narrow therapeutic index on this schedule
- 		Solubility of agent major problem for other schedules

- Early Stage, Athymic Mouse Xenograft

## Geldanamycin Bead

## Geldanamycin BeadsIdentify Hsp90 As Binding Partner

*Neckers et al, PNAS 91:8324, 1994*

**1)  Bead-Geld**
**2)  Bead-Geld + Geld**

**3)  Bead-Geld + Geldampicin**
**4)  Bead**

## Hsp 90

**B.**

**A.**

## Three Dimensional View Of Geldanamycin Binding Pocket In Amino Terminus Of Hsp90

**Three Dimensional View Of Geldanamycin Binding Pocket In Amino Terminus Of Hsp90**

*Stebbins et al, Cell 89:239, 1997*

## 17-AAG Binds To Hsp90 & Shares Important Biologic Activities With Geldanamycin

- dose (nM)

- erbB2 (% of base line)

- Raf-1 (% of base line)

*Schulte & Neckers, Cancer Chemother Pharmacol 42: 273, 1998*

- dose (nM)

## UCN-01

- Potent antiproliferative agent
- Cell cycle arrest
- DNA-damage G2 checkpoint abrogation

- 37nM
- 300-600 nM
- ~50nM

- IC50

* **(DTP screen)*

## A DNA Damage G2 Checkpoint Is Mediated By CDKs: UCN-01 Action

## UCN-01 Infusional Phase I TrialG2 Checkpoint Abrogation

- % G2 checkpoint abrogation

- % G2 checkpoint abrogation

- nM UCN-01

- UCN-01 (mg/m2/day)

## Challenges In Pursuing TheMolecular Therapeutics Of Cancer

-   Must change thinking from histologic to molecular
- 	diagnoses (CGAP, array technology)
-   Develop new means (imaging, probes) to assess
- 	molecular pharmacodynamics
-   Must move away from cytotoxicity as sole primary
- 	endpoint:  assess and evaluate cytostatic effect
-   Promote patient participation in clinical trials
-   Develop speed and efficiency in answering critical
- 	 clinical questions

## Goals For Cancer Drug ScreeningIn The New Millennium

-   Associate novel chemotypes with defined targets
-  may utilize purified targets at the “front end”
-  may define targets in pathway/organisms
-  may “retrofit” molecules to targets or pathways
- 	by statistical approaches
-   Allows facile tools for chemical/pharmacological
- 	optimization
-   Define targets of relevance to and translatable in
- 	early clinical trials

## Summary:Developmental Therapeutics Program, NCI

-   Novel agents directed at molecular targets
- important to cancer pathogenesis
- and progression
-   Interdisciplinary collaborators: academia,
- industry, intramural NCI
-   Contribute agents and regimens for use by
- intra / extramural investigators

## Acknowledgements

**NCI**

- V. Narayanan, R. Schultz
- J. Johnson, S. O’Barr
- M. Hollingshead, S. Stinson
- L. Rubinstein
- A.Monks, N. Scudiero
- K. Paull, D. Zaharevitz, S. Bates
- S. Holbeck, J. Weinstein
- A. Senderowicz
- A. Murgo, S. Arbuck
- G. Kaur, P. Worland, Q. Wang
- P. O’Connor
- L. Neckers, L. Whitesell
- D. Newman

- H. Piwnica-Worms
-       *Wash U*
- V. Pollack
-      * **Pfizer*
- M. Roberge
-       *U. Brit. Columbia*

## Our next speaker is:

**Ms. Shannon Decker**
**Office of the Associate Director**
**Developmental Therapeutics Program**