# Presentation: 095077

## LeuTech® BLA # 99-1407 Review Team

**Chana Fuchs, Ph.D.****	****Product****	**
**Lydia Martynec, M.D.****	****Nuclear Medicine**
**Robert Lindblad, M.D.****	****Clinical**
**Leon Epps, Ph.D.****	****	****Radiochemistry**
**Satish Misra, Ph.D.****	****	****Bios****tatistics**
**Martin D. Green, Ph.D.****	****Pharm/Tox**
**Mary Andrich, M.D.****	****	****BioResearch Monitoring**
**Deborah Trout ****	****	****Facilities Specialist**
**Michael Noska, M.S. ****	****Project Manager**

## THE PRODUCT

**LeuTechTM is a kit for the preparation of Technetium Tc 99m labeled RB5 anti-CD15 monoclonal antibody, intended for intravenous administration after reconstitution and radiolabeling. **
**Each kit contains one reagent vial with 0.25 mg lyophilized, partially reduced RB5 murine IgM antibody and excipients, and a 2mL ampule of 500mg/mL ascorbic acid for injection (Abbott) as a diluent. **

**Notes:**
Good morning
I guess we’ll start with a very brief introduction of the product and continue with the clinical  presentation.

The product under discussion is Leutech, .....

## THE PROPOSED INDICATION

**LeuTech “is indicated for the diagnosis of appendicitis in patients with equivocal signs and symptoms. It is useful to rule out appendicitis in patients presenting with equivocal diagnostic evidence.”**

## THE Tc 99m LABELED ANTIBODY

**RB5 anti-CD15 IgM is a murine mAb. **
**General structure of a partially reduced, labeled IgM:**

**Notes:**
The monoclonal antibody RB5 anti CD15 is a murine IgM.

Here’s a cartoon of a labeled, partially reduced IgM.

IgMs are pentamers and therefore contain 10 sites for interaction with the target antigen.

Rb5 IgM is partially reduced to allow it to complex with the Technerium label.
The reduction process releases free sulfhydrils for reaction with the technetium 99m and formation of the labeled Tec-Antibody complex

This is just a cartoon and there are a number of other sites which can be reduced during the partial reduction reaction. Additionally, I am showing 2 technetium molecules complexed to this IgM, but different amounts of Technetium may actually bind.

If licensed, RB5 anti CD15 would be the first IgM to be licensed by CBER.
 (J chain,)

## THE TARGET ANTIGEN

**CD15**
**A branched oligosaccharide, Lacto-N-neo-fucopentaose III, that can be found on glycolipids and glycoproteins expressed on cell membranes**
**Gal ********1 ******** ****4GlcNAc********1 ********R**
**	****	****    ****	****	****   ****3**
**	****	****     ****	****	****   ******
**  ****	****	****	****     ****Fuc********1**
**CD15 is an adhesive carbohydrate moiety that can bind to itself and to other carbohydrates.  It is important in cell-cell recognition and migration.**

**Notes:**
The target antigen to which this antibody binds is CD15.

This is a branched oligosaccharide, with the official name of Lacto-N-neo-fucopentaose III

this carbohydrate moiety defines the CD15 family of antigens

and  plays a role in mediating phagocytosis, bactericidal activity and chemotaxis.

## THE TARGET ANTIGEN 

**CD15 is reported to be strongly expressed by neutrophils, eosinophils, monocytes and normal myeloid precursor cells. Activated T cells and Reed-Sternberg cells have also been reported to express CD15.**
**ALTERNATE NAMES**
**3-FAL  **
**LNFP III  **
**Lewis X (Le****x****)**
**SSEA-1 epitope**

**Notes:**
In the literature, information on CD 15 can also be found under these names:

all refer to carbohydrate antigens in which the immunodominant structure is the oligosaccharide described above.

## THE RATIONALE

**Appendicitis is associated with a neutrophilic infiltration of the muscularis and, usually, the appendix mucosa.**
**The technetium Tc 99m labeled Rb5 IgM antibody binds the CD15 epitopes on the polymorphonuclear neutrophils found at sites of infection/ inflammation, allowing imaging of the site.**

**Notes:**
Rationale for using this antibody to diagnose equivocal appendicitis is that....

There are approximately 500,000 binding sites for the anti-DC15 antibody per cell

(...an accumulation of PMNs)

## MANUFACTURING

**Palatin controls all steps in the manufacturing process, is responsible for release of the product at each stage in the manufacturing process, and performs QC  release testing.**
**One contract manufacturer makes the Rb5 IgM drug substance. **
**A second contract manufacturer then prepares the final drug product.**

**Notes:**
Manufacturing of the monoclonal antibody occurs at a number of sites

Palatin, the sponsor of this BLA, is responsible for and controlls...

manufacturing and filling are done by contracting companies.

(MCB, WCB, fermentation, IgM purification and its partial reduction

(formulation, filling, lyophilization, labeling, kit packaging and subsequent shipping).

## A number of significant outstanding manufacturing issues remain to be resolved.

**Notes:**
Currently...

(propritary information)

## LeuTech® Primary Clinical Trials 

**TECHNETIUM ****99M ****Tc LEUTECH****TM**
_**Dose Antibody**_** (Anti-CD 15 IgM):**
**	**** ****75 - 125 ********g **
_**Radiolabel Dose**_**:**
**	****Standard Adult:  10-20 mCi ****99m**** Tc**
**     ****< 17 y/o:               0.21 mCi/Kg up to a                            ****	****                        maximum of 20 mCi**

## IMAGING PROTOCOL(Standardized Across All Sites)

**Total Imaging Time = 90 Minutes **
**Immediate Dynamic Acquisition:  10 frames at 4 minute each**
**Ambulate x 10-15 minutes, void**
**Static Planar Images:  Supine Anterior**
**                                           ****Posterior**
**                                           ****RAO, LAO**
**                                           ****Standing Anterior Image**
**Acquisition:  Anterior Image 1 million counts then all ****	****	****	****     subsequent images for same time**

## BLINDED READING PROTOCOL

**Independent Blinded Readers**
**Aggregate Read(Majority Rules: 2/3)**
**Provided with Demographics Only**
**	****	****(Age, Sex, Height and Weight)**
**Image Set Randomized**
**Standard Format on Computer Database**
**Independent Evaluation**
**Electronic CRF**

## BLINDED IMAGE EVALUATIONREPORT

_**Result**_
****_** **_
_**Negative**_**   or     **_**Positive**_
**	**** ****	****	****                                        ******
_**	**__**	**_**    ****	****                       **_**Uptake Pattern**_
_**	**__**	**_**	****       ****	****                ******** ****	****         ******
**                   **_**Location Uptake **_**       **_**Intensity Uptake**_**  **
**                   ****(Appendicitis Zone) (Low, Moderate, High)**

## BLINDED IMAGE EVALUATIONREPORT

_**Time Scan Positive**_**  (Minutes Into Study)**
_**Uptake persists throughout study**_** (Y/N)**
_**Technical Quality**_
_**LeuTech**_**TM **_**Diagnosis**_** ******** Negative**
_**	**__**	**__**	**__**	**_**          ******** ****Positive - Acute Appendicitis**
**	****	****	****	****	****	****        ****- Other Infection**

## READER TRAINING

**Same Training for Principal Investigators and Blinded Readers**
**Utilized 8 Cases from Phase 2 Trial**
**Presentation of 6 (+) Cases, (2) Negative Cases**
**Specified Criteria for Image Interpretation**
**Image Pitfalls**
**Followed by Practice Blinded Reads **
**	****	****(15 Phase 2 Cases)**
**Joint Review with Dr. Kipper **

## INSTRUCTIONS TO ALL READERS

**Read for Highest Sensitivity and Negative Predictive Value**
**Read with mindset of being afraid to miss the diagnosis of appendicitis**
**Search carefully for appendicitis; do not give equivocal readings**

## SUBMITTED IMAGE DATABASE

**203 Patients Enrolled**
**	****	****     ******
**	****200 Digital Image Data**
**	****3 Films Scanned In**
**Submitted Database - Organized by Site and**
**	****	****	****	****      ****Patient Number**

## CBER IMAGE ASSESSMENT

**Adherence to Protocol**
**Completeness Dynamic and Planar Dataset**
**Time Of Positive Images**

## IMAGE QUALITY ASSESSMENT

**Image Contrast and Color Display**
**Patient Information Redacted (Name, Site #)**
**Complete Data Set**
_**Evaluable at 30 minutes**_**:  202/203**
_**Dynamic**_**:  Complete Set 196/203 (97%) Patients**
**	****	****	****	****	****	**
_**Static**_**:  Complete Set 164/203 (81%) Patients**
**6/203 Images Technically Unevaluable**

## TIME TO POSITIVE SCANTP/READER(N=59)

## Clinical Review Outline

**Phase 2 trial**
**Phase 3 trial**
**trial design**
**trial results**
**equivocal appendicitis population**
**performance phase 3  **
**pooled phase 2 and 3**
**management phase 3  **
**Safety**

## Phase 2 Trial Design

**Eligibility criteria**
**Right lower quadrant pain**
**Signs, symptoms or laboratory findings suggestive of atypical appendicitis**
**PID not excluded**
**Management questionnaire****: pre and post-scan**
**Disposition: home, admit for observation, surgery **
**likelihood of appendicitis**

## Phase 2 Trial Design

**Performance assessment **
**Offsite Blinded Readers**
**Onsite Readers**
**Safety**
**Vital signs**
**Laboratory data**

## Phase 2 Trial Results

**2 sites ; 56 subjects**
**49 patients - site A**
**7 patients - site B**
**45% male ; 55% female **
**Age 9-77y ; Median = 27**
**50% incidence of appendicitis**

## Phase 2  PerformanceComparison of aggregate blind read (Offsite-white) to Onsite reads (yellow)

## Phase 3 Trial 

**Eligibility criteria**
**Management questionnaire**
**Phase 3 trial results**
**equivocal appendicitis patient population**
**eligibility criteria**
**surgeon’s pre-scan disposition plan**
**surgeon’s pre-scan likelihood estimate**
**Performance**
**evaluable subjects**
**subgroups**
**Management**

## Phase 3 Trial Design

**Eligibility Criteria :RLQ Pain Plus **
**Atypical history**
**no gradual onset, no increasing  intensity,not aggravated by movement, non migrating**
**Atypical physical exam**
**no McBurney’s point tenderness,no referred tenderness, no abdominal wall spasm**
**Temperature less than 101****0****F**
**WBC <10,500/mm****3**
**Only one criteria need be present to qualify for the study**
**Women with PID excluded**

## Phase 3 Trial Design

**Management Questionnaire**
**Used to assess clinical utility of LeuTech**
**Surgeons were asked to assess the following:**
**Anticipated disposition of patient pre and post scan**
**likelihood of appendicitis pre and post scan**

## Phase 3 Trial Design

**Management Questionnaire**
**Surgeon’s likelihood estimate**
**0-19%     - ****	****almost definitely not appendicitis**
**20-39%   - ****	****probably not appendicitis**
**40-59%   - ****	****indeterminate appendicitis**
**60-79%   - ****	****probably appendicitis**
**80-100% - ****	****almost definitely appendicitis**** **

## Phase 3 Trial Results

**10 sites**
**6 sites 19-39 subjects per site**
**4 sites **_**<**_** 11 subjects per site**
**60% Male ; 40% Female **
**Age 5-85 ; Median = 26 **
**30% Incidence of Appendicitis **
**Incidence per site ranged from 0 - 75%**

## Phase 3 Trial Results

**Equivocal appendicitis population**
**Based on absent classic signs and symptoms**
**Surgeon’s pre-scan disposition plan**
**Surgeon’s pre-scan likelihood estimate**

## Incidence of Appendicitis Based on Number of Positive Entry Criteria

**Incidence of Appendicitis within Surgeon’s Pre-scan Disposition Plan**

**Incidence of Appendicitis within Surgeon’s Pre-scan Likelihood Groups**

## Phase 3  PerformanceComparison of aggregate blind read (Offsite-white) to Onsite reads (Onsite-yellow)

## Phase 3  PerformanceAggregate Blinded Read (N=172)Based on 2 - 6 Positive Entry Criteria

## Phase 3  PerformanceAggregate Blinded Read (N=121) Based on Pre-scan Admit for Observation Disposition Plan

## Phase 3  PerformanceAggregate Blinded Read (N=200)Surgeon’s Pre-scan Likelihood Estimates

## Percent of Patients with a Given Eligibility Criteria and Surgeon’s Pre-scan Likelihood Estimates

## Phase 3 - WBC < 10,500/mm3                   Incidence of Appendicitis = 13%N = 114

## Phase 3 - WBC > 10,500/mm3                   Incidence of Appendicitis = 51%N = 86

## Women 14-35y Phase 3Pre-scan likelihood estimate of appendicitis	20-79%Incidence of Appendicitis	19%

## Pediatrics Pooled Phase 2 and 35-9y - N=15 :  Incidence=47%

## Pediatrics Pooled Phase 2 and 3 10-17y - N= 48  Incidence=27%

## Geriatric >65 Pooled phase 2 and 3  N=12    Incidence- 50%

## Performance in Subjects with “Other Infections”Pooled Phase 2 and 3 

**Phase 3 trial  aggregate blind read - all FPs occurred in subjects with “other Infections” **

## Management-DispositionPhase 3

## Safety data

**HAMA - 54 subjects**
**No HAMA response**
**defined as a 4 fold rise in titer**
**30 normal subjects re-exposed**
**5 positive titers**
**2 mild **
**3 moderate**

## Safety Data

**No serious adverse events (439 subjects)**
**Vasodilatation- most common event (2.5%)**
**all others less than 1%**
**Vital signs **
**no clinically significant changes noted **
**Laboratory parameters**
**No clinically significant changes noted **