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“microdosing” in Google: first 4 hits

Gesponsorde KoppelingenU.S. Microdosing Studieswww.acciumbio.com      FDA Exploratory-IND Services; Predict failure and success

now!

Microdosing - Wikipedia, the free encyclopedia Microdosing is a technique for studying the behaviour of compounds in vivo throughthe administration of doses so low they are unlikely to produce ...http://en.wikipedia.org/wiki/Microdosing - 19k

Xceleron - Microdosing Human microdosing (Human Phase 0) is a new concept which relies on the ultrasensitivity of accelerator mass spectrometry (AMS). ...http://www.xceleron.co.uk/index.pl?id=2188 - 20k

Human microdosing proves its value in drug R&D Human microdosing proves its value in drug R&D Xceleron has announced thelong-awaited results of the CREAM trial into human microdosing in drug

development ...http://www.drugresearcher.com/news/ng.asp?n=58575-human-microdosing-proves -

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What is Microdosing ?

MicrodosingFrom Wikipedia, the free encyclopedia

Microdosing is a technique for studying the behaviour of compounds

in vivo through the administration of doses so low they are unlikely to produce whole-body effects. . . . . This allows us to see the Pharmacokinetics of the drug with almost no risk of side effects. This is called a Phase 0 study and is usually done before testing onanimals to predict whether a drug is viable for the next phase oftesting. This is lowering the cost spent on non viable drugs and theamount of testing done on animals . . . . . . .

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Conducting a human Phase 0 microdose study

workshop AGAH 19 April 2008

Berend OosterhuisScientific Director EDS NLPRA International

Experiences at PRA EDS in The Netherlands

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Selecting the human dose (1)

“In the current context, the term ‘microdose’ wouldbe less then 1/100th of the dose calculated to yield a pharmacological effect of the test substance based on primary pharmacodynamic data obtained in vitro and in

vivo(typically doses in or below the low microgram range) and at a maximum dose of 100 microgram.”

• EMEA / FDA definition of microdose:

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Selecting the human dose (2)

• Difficulties with EMEA / FDA definition– 100 microgram as upper limit is arbitrary– calculation/prediction of human pharmacological dose

often uncertain

• Guiding suggestions:– aim for (free) plasma concentrations ≤ 2 x EC50 or

scaled dose ≤ 2x ED50 in most reliable pharmacological test/animal model

– include in pharmacology tests known related agonists as “bench mark”

– bottom line: any dose acceptable if supported by “clean” toxicology, including safety factor single dose tox study

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• Single dose 100 x human microdose in rats with 8 days observation– iv and intended human route (n=6 per route)– biochemistry on days 2 and 8– animals sacrificed on day 8– gross necropsy, limited histopathology

• Abridged genotoxicity (optional)• Comparative in vitro metabolism; microsomes or

hepatocytes• Single i.v. dose CV safety in dogs (100 x microdose)

– 48h observation cardiovascular parameters

• Microdose tox program agreed between PRA and Ethics Committee (late 2003)

Supporting toxicity studies(2)

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• Single dose 100 x human microdose in rats with 8 days observation– iv and intended human route (n=6 per route)– biochemistry on days 2 and 8– animals sacrificed on day 8– gross necropsy, limited histopathology

• Abridged genotoxicity (optional)• Comparative in vitro metabolism; microsomes or

hepatocytes• Single i.v. dose CV safety in dogs (100 x microdose)

– 48h observation cardiovascular parameters

• Microdose tox program agreed between PRA and Ethics Committee (late 2003)

Supporting toxicity studies(2)

Human dose (µg)

Safety factor

200 200

300 300

400 400

….

1000 1000

>1000 1000

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• Varations accepted by Ethics Committee, e.g.– 14 days observation with interim sacrifices on day 2

(doubling the number of animals)– 1000x safety factor and hERG instead of CV safety in

dogs

• What is a ‘clean’ tox study ?– slight ‘no adverse’ effects in single dose tox study

acceptable, especially if 1000x safety factor

• Microdose-toxicology programs (GLP) often outsourced by Sponsor– lack of internal flexibility?– most programs were conducted at NOTOX,

Netherlands

Supporting toxicity studies(3)

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• Varations accepted by Ethics Committee, e.g.– 14 days observation with interim sacrifices on day 2

(doubling the number of animals)– 1000x safety factor and hERG instead of CV safety in

dogs

• What is a ‘clean’ tox study ?– slight ‘no adverse’ effects in single dose tox study

acceptable, especially if 1000x safety factor

• Microdose-toxicology programs (GLP) often outsourced by Sponsor– lack of internal flexibility?– most programs were conducted at NOTOX,

Netherlands

Supporting toxicity studies(3)

total time for tox program: 10-12 weeks from receipt

test substance/documentation to draft reports

~7 gram of test substance required

per compound

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CMC aspects and IMP “manufacturing”(1)

• Should drug substance (API) for human microdose be manufactured under GMP?– not addressed in EMEA position paper– FDA exploratory IND allows same batch as in

toxicology studies– MHRA (UK) allows “GLP quality”– radiolabelled substance (for AMS): not drug

substance but (novel) excipient (CoA and some other data needed)

– don’t mix drug substance and radiolabelled substance before manufacturing of IMP

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CMC aspects and IMP “manufacturing”(1)

• Should drug substance (API) for human microdose be manufactured under GMP?– not addressed in EMEA position paper– FDA exploratory IND allows same batch as in toxicology

studies– MHRA (UK) allows “GLP quality”– -> no GMP but concise CMC description needed in IMPD– radiolabelled substance (for AMS): not drug substance

but (novel) excipient (CoA and some other data needed)

– don’t mix drug substance and radiolabelled substance before shipment to PRA (ship separately)

amounts needed for entire study:“cold” compound 50-100 mg

labelled compound corresponding with 20-30 µCi

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• Manufacturing of “drug product” on site !– manufacturing under GMP: manufacturing licence and

QP release at clinical site – on the morning or day before dosing to subjects– high risk of adsorption losses during preparation and

dosing– always run test preparations and mock

administrations– analytical testing of at least “hot” dose by LSC– select best composition, procedures and materials for

vessels, syringes, infusion lines– keep samples to assess actually administered doses

during study

CMC aspects and IMP “manufacturing”(2)

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• Keep the IMPD (and IB) lean and functional– IMP documentation in CTA can be IB + “IMPD-Addendum”

containing the CMC data– Drug Product section to describe how “product” will be

manufactured, control parameters for test batch, which specifications should be met

– test batch preparation usually after CTA submission– -> Drug Product section may need amendment based on

outcome of test preparation results

CMC aspects and IMP “manufacturing”(3)

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• Keep the IMPD (and IB) lean and functional– IMP documentation in CTA can be IB + “IMPD-Addendum”

containing the CMC data– Drug Product section to describe how “product” will be

manufactured, control parameters for test batch, which specifications should be met

– test batch preparation usually after CTA submission– -> Drug Product section may need amendment based on

outcome of test preparation results

CMC aspects and IMP “manufacturing”(3)

we have seen considerable delays from internal SOPs

and requirements by Sponsor’s regulatory group

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• For radioactive doses ≤ 1 μCi:– “trivial” radiation burden ICRP-62 (<< 0.1 mSv)– no (animal studies to support) dosimetry required

• Conduct study outside area for normal radiolabel studies– to avoid contamination of subjects and samples

• Screening of subjects for background radioactivity ?

Particulars about the clinical study

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• LC-MS/MS– >100 x more sensitive than ‘classical’ HPLC: picogram/mL

range– can provide parent vs. metabolite/structure information – no 14C radiolabeled compound required

• Accelerator Mass Spectrometry (AMS)– ultrasensitive: femtograms (10-15 g/mL) and below– 14C radiolabeled compound required (50-200 nanoCurie)

• Only a few providers for AMS worldwide– Xceleron, York UK and Gaithersburg USA– Accium Biosciences, Seattle, USA– Vitalea Sciences, USA– IAA, Tokyo, Japan

Bioanalysis and role of AMS(1)

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Bioanalysis and role of AMS (2)

• AMS “counts” 14C-atoms– 14C radiolabeled compound required (50-200 nanoCurie

per dose)

• Samples converted to graphite before AMS– direct AMS only gives total 14C content– off-line HPLC separation of parent compound and

metabolites

• Verification of HPLC separation by “fractionation”– need certainty about full separation of parent !

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0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.035

0.040

0.045

0.050

0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0

Retention Tim e (Minutes)

Therapeutic dose

Microdose

LC-AMS parent vs. metabolite separation of diazepam

Bioanalysis and role of AMS (3)

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0.10

1.00

10.00

0 20 40 60 80 100 120 140Time (h)

ng

/mL

Parent IV microdose

C-14 IV microdose

Profile

14C

Parent

Diazepam IV microdose

diazepam: total radioactivity and parent concentration-time profile

Bioanalysis and role of AMS (4)

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Concluding remarks

• planned human microdose supported primarily by ‘clean’ tox study with safety factor (100-1000x) single dose in one species

• no clear rationale for 100 microgram upper limit

• pharmaceutical procedures to administer the right dose are critical

• AMS is unique analytical tool; off-line separation of parent is essential

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Concluding remarksConducting a human Phase 0 microdose study

Time-critical activities Parallel activities Minimal time

Amount of substance

Reduced toxicity program

RadiosynthesisCMC and IMPD

12 weeks 7 gram

Compilation CTA dossier Writing IB, protocol, subject information

3 weeks

CTA approval Test batch IMP and QC

2 weeks

Clinical Study + recruitment/screening

First samples to AMS lab; setup LC-AMS

5 weeks < 0.5 gram20-30 µCi 14C

LC-AMS and assay of samples

Initiate PK evaluation

6 weeks < 0.1 gram< 5 µCi 14C

Draft PK report 1 week

Total 29 weeks ~ 7.5 gram25-35 µCi 14C

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Concluding remarksConducting a human Phase 0 microdose study

Time-critical activities Parallel activities Minimal time

Amount of substance

Reduced toxicity program

RadiosynthesisCMC and IMPD

12 weeks 7 gram

Compilation CTA dossier Writing IB, protocol, subject information

3 weeks

CTA approval Test batch IMP and QC

2 weeks

Clinical Study + screening

First samples to AMS lab; setup LC-AMS

5 weeks < 0.5 gram20-30 µCi 14C

LC-AMS and assay of samples

Initiate PK evaluation

4 weeks < 0.1 gram< 5 µCi 14C

Draft PK report 1 week

Total 27 weeks ~ 7.5 gram25-35 µCi 14C

Do you consider microdosing?

KISS !(keep it small and simple)