VijithRoy
☆    

India,
2020-07-21 04:25
(14 d 09:18 ago)

Posting: # 21764
Views: 667
 

 Glucose Clamp Study [PK / PD]

Dear all,

Glucose clamp study is a technique to measure the insulin resistance. still it is followed in many CRO's.

Am new to this field, Can anyone please describe about the technique on How it works? Principle ? For in which case it is been used ? Applications?

What is the main concept and learning part we should get thorough in it ?

Thanks in advance.
ElMaestro
★★★

Belgium?,
2020-07-21 10:24
(14 d 03:19 ago)

@ VijithRoy
Posting: # 21765
Views: 617
 

 Glucose Clamp Study

Hi VijithRoy,


» Am new to this field, Can anyone please describe about the technique on How it works? Principle ? For in which case it is been used ? Applications?
»
» What is the main concept and learning part we should get thorough in it ?


the idea of the glucose clamp is straightforward:
Human's have a tendency to keel over and expire rapidly if their glucose levels get too low. Imagine you can give a constant infusion of glucose to keep the glucose constant in blood. I.e. you seek to ascertain that whatever glucose disappears from the blood is matched by the glucose appearing. That is the principle of the (euglycemic) clamp and it will work for situtions when "something" (see example 2 below) could otherwise cause blood glucose to drop dangerously.

So under a running clamp you need to constantly measure blood glucose and you constantly need to adapt and adjust the glucose infusion rate to keep the level constant at a safe level / in a well defined window.

Examples of application:
  1. Insulin resistance. The need for glucose infusion is low(er), because cells don't use of the glucose in the blood. The insulin does not help glucose away from the blood and into the cells, so to say.
  2. BE of a newly formulated long-acting insulin: You give a dose of the insulin. Now, then due to the effect of glucose you put the subject under a clamp, to keep glucose levels up and safe. During the clamp you measure the new insulin levels as primary for AUC and Cmax, but you can also measure AUC of glucose and other stuff as a secondary.
The idea is simple and it works great. However, the technical difficulty is considerable: It is not easy to constantly measure glucose in blood. This, however simple it may sound, is annoyingly error-prone. There is measurement error, but also a lot of error due to blood's natural tendency to clot (you do not really measure it is plasma or serum). There is no noninvasive technique for it (one company uses a noninvasive technique to approximate blood levels by interstitial levels of glucose, but it isn't exactly the same, and it does not respond rapidly to changes in the blood levels).

So glucose clamp = one subject, one glucose infusion pump + a lot of staff members who are constantly occupied taking invasive measurements of blood glucose and adjusting the glucose infusion pump accordingly.
All this is done in the usual phase I setup with extra vigilance for spotting hypo events. At a lab you may need an immuno-assay for measurements of the new insulin if that's what you are doing, and those measurements are also associated with various annoying pitfalls, of course.
(For starters: Your standards may need to be in horse blood or horse serum, now, try and think which authority would accept that for a small synthetic molecule in a normal BE trial?).

I could be wrong, but...

Best regards,
ElMaestro

"Pass or fail" (D. Potvin et al., 2008)
VijithRoy
☆    

India,
2020-07-21 10:38
(14 d 03:05 ago)

@ ElMaestro
Posting: # 21766
Views: 611
 

 Glucose Clamp Study

Thank you sir.
it was really good and crisp one.

Under Clamp technique, Only insulin like drugs can be tested ?


Edit: Full quote removed. Please delete everything from the text of the original poster which is not necessary in understanding your answer; see also this post #5[Helmut]
ElMaestro
★★★

Belgium?,
2020-07-21 10:51
(14 d 02:52 ago)

@ VijithRoy
Posting: # 21767
Views: 604
 

 Glucose Clamp Study

Hello VijithRoy,

» Under Clamp technique, Only insulin like drugs can be tested ?

No, in principle any situation when you wish to keep glucose levels up and safe you can do a clamp.
I recall in India how subjects were drinking glucose water before taking a dose of metformin in a BE trial on hevo's. In such a situation a clamp might have achieved the same. The example is not very good, of course, because it is easier to drink glucose than to do start a clamp, but I hope you get the idea.
(metformin: hevo's were puking when drinking the sweet stuff at 7:53AM, and when one subject pukes, 17 others will follow, so these studies with oral glucose solution had a lot of discontinuations and AEs and stuff; why the f%ck not just try and standardise intake of something sweet which is liked by volunteers: Halwa, Gulab Jamun, ice cream, but no.... glucose solution dictated by DCGI/CDSCO/ethics... that's beyond me.... I am sure there are good arguments, I just don't know of them or will not recognise them as better than a lot of other alternatives :-D:-D)

I could be wrong, but...

Best regards,
ElMaestro

"Pass or fail" (D. Potvin et al., 2008)
VijithRoy
☆    

India,
2020-07-22 04:11
(13 d 09:33 ago)

@ ElMaestro
Posting: # 21769
Views: 551
 

 Glucose Clamp Study

Dear ElMaestro !!

Thank you so much :-)
i got your point and here in my working place (BABE Unit), clamp study is going to conduct in up coming weeks. the study goes like this,

Subjects will be housed (Day 0), that so to ensure 10hr fasting before pre-dose.

On day of dosing, One hand will be cannulated for blood collection and other hand for Continous IV 20% Dextrose solution will be infused.

Once the subject gets stable, pre dose samples are taken and clamp value is measured (Mean glucose level). Then T/R 0.4IU/Kg will be administered SC. Blood sampling 0.3ml for every 5mins for 12hrs & 0.5ml for evry 1omins for 12-24hr.

Then with 20% dextrose adjusted.

this is how current rough procedure study goes out here.


Edit: Full quote removed. Please delete everything from the text of the original poster which is not necessary in understanding your answer; see also this post #5[Helmut]
ElMaestro
★★★

Belgium?,
2020-07-22 09:02
(13 d 04:41 ago)

(edited by ElMaestro on 2020-07-22 09:20)
@ VijithRoy
Posting: # 21771
Views: 538
 

 Good luck :-)

Hi VR,

good luck with your trial.
Please follow up and post about your experience once the study is done, there are so many unexpected little practical surprises in these studies. Few CROs specialise in this area.

I could be wrong, but...

Best regards,
ElMaestro

"Pass or fail" (D. Potvin et al., 2008)
VijithRoy
☆    

India,
2020-07-22 10:38
(13 d 03:05 ago)

@ ElMaestro
Posting: # 21773
Views: 527
 

 Good luck :-)

» Please follow up and post about your experience once the study is done, there are so many unexpected little practical surprises in these studies. Few CROs specialise in this area.

Sure sir.

Either i got to know many sensible events during this study and sure i will share the overall experience once get done.

Thank you so much.
VijithRoy
☆    

India,
2020-07-29 13:51
(5 d 23:52 ago)

@ ElMaestro
Posting: # 21797
Views: 240
 

 Good luck :-)

» Please follow up and post about your experience once the study is done, there are so many unexpected little practical surprises in these studies. Few CROs specialise in this area.

Once again, Hello !!

Successfully done one clamp study for insulin drug for 24 hour under fasting state on healthy subject.

Really it was so interesting on every 5mins & 10mins blood collection, how team co-ordination works and also the study is mostly depend upon machine based algorithms (YSI Glucose analyser & software to calculate & output the clamp values), i found the clamp value was changing over each ysi glucose analyser though it is calibrated every 2hours.

Man power is most needed to assist proper maintaining the clamp procedure.

The nurse and phlebotomist has the major pressure on them, since they are in the blood collection and subject monitoring process.

Though i spent whole 24hrs in the study, i miss the rationale behind the study.
which drugs need this glucose clamp study ?

Respect your reply !!

Thank you.


Edit: Full quote removed. Please delete everything from the text of the original poster which is not necessary in understanding your answer; see also this post #5[Helmut]
ElMaestro
★★★

Belgium?,
2020-07-30 09:22
(5 d 04:21 ago)

@ VijithRoy
Posting: # 21803
Views: 214
 

 Good luck :-)

Hi VR,

» Really it was so interesting on every 5mins & 10mins blood collection, how team co-ordination works and also the study is mostly depend upon machine based algorithms (YSI Glucose analyser & software to calculate & output the clamp values), i found the clamp value was changing over each ysi glucose analyser though it is calibrated every 2hours.

This is one of the practical annoyances. The analyzers change all the time, there's heavy drift in its calibration and there is no obvious way to fix it during the clamp. Many have tried. :lookaround:
Add to that the clogging tubes everywhere....

» Man power is most needed to assist proper maintaining the clamp procedure.

Indeed, these must be some of the most labour-intensive trials.

» The nurse and phlebotomist has the major pressure on them, since they are in the blood collection and subject monitoring process.'

Plus the poor guy who is constantly screaming and kicking the YSI equipment. That guy will apply for early retirement after just a few trials, I guarantee it.

» Though i spent whole 24hrs in the study, i miss the rationale behind the study.
» which drugs need this glucose clamp study ?

You ask which studies "need" a clamp. That is not particularly well defined. At least not in a regulatory sense.
What I do know, is that ICH E6 §2.3 says:
"The rights, safety, and well-being of the trial subjects are the most important considerations and should prevail over interests of science and society."
The glucose clamp can handily keep the blood glucose above an unsafe low threshold. So any drug which lowers blood glucose -or which has the ability to do so at otherwise unethical/unsafe/dangerous levels- is a candidate for remedial action to mitigate the risk of hypo-events, and a euglycemic clamp is handy for that purpose.
There are other types of study, of course, where a clamp is handy to study the body's response to stimuli or lack thereof. Some clamps involve a peaking glucose, for example you may wish to study the body's own production of insulin/leptin/C-peptide/prostaglandins etc in response to a well-defined increase in glucose. A clamp-type of study is a good guess in such situations, since the increase in glucose is not so well-defined if you hand the volunteers a handful of Snickers bars or a gallon of Mountain Dew., :-)

I could be wrong, but...

Best regards,
ElMaestro

"Pass or fail" (D. Potvin et al., 2008)
VijithRoy
☆    

India,
2020-07-30 14:59
(4 d 22:44 ago)

@ ElMaestro
Posting: # 21806
Views: 190
 

 Good luck :-)

Dear ElMaestro,

Thank you for your last reply with examples. really broadening up my mind.

» » The nurse and phlebotomist has the major pressure on them, since they are in the blood collection and subject monitoring process.'
»
» Plus the poor guy who is constantly screaming and kicking the YSI equipment. That guy will apply for early retirement after just a few trials, I guarantee it.

Hahaa, If that in case, I will be the one who will be applying for it. Because, since i am a trainee, i was handling YSI machines. (But happy that i never felt such hectic pressure i would say, may be as you said, after a few trials :-D)


So, Here we performing on Healthy male subjects under fasting condition, that so, is it mandatory for every generic drug (Eg - our insulin test and reference products) should conduct on under Healthy subjects under fasting condition ?

Is this study kind of assessing the dosage regimen, efficacy, ADR on Healthy subjects ?

Thank you in advance, Appreciate your reply.
ElMaestro
★★★

Belgium?,
2020-07-30 23:31
(4 d 14:12 ago)

@ VijithRoy
Posting: # 21810
Views: 166
 

 Good luck :-)

Hi VR,

» So, Here we performing on Healthy male subjects under fasting condition, that so, is it mandatory for every generic drug (Eg - our insulin test and reference products) should conduct on under Healthy subjects under fasting condition ?
»
» Is this study kind of assessing the dosage regimen, efficacy, ADR on Healthy subjects ?

I can't tell from the info you have given what type of study you are doing, but I think you are saying you are comparing two insulins. It sounds like a BE study.
In that case you are taking blood samples every now and then, probably after the subjects have been given the insulin as an s.c. injection. In these blood samples you measure insulin levels.
Next, you draw a graph showing the concentration of one insulin as function of time after injection, and on the same graph you draw the other insulin. The two are bioequivalent if the two curves are sufficiently close to each other by some well-defined criteria. The criteria define sameness of the rate and extent of the insulin getting from the site of injection into the blood stream.

And it is funny, because in fact it is not so difficult to take these samples that are used to make those graphs. 95% of all the tedious work with a clamp study of that type, is the clamp itself which is only used to keep the subject safe, but not so much used to compare the two insulins. It is almost unfair :-) (but let it be said, if one insulin works much better than the other, then possibly you will see a different need for glucose; things are usually not that clear in practice).

So, I think, without being absolutely sure that the answer is, that you are mainly studying if the rate and extent of absorption is similar for two products. That is a primary purpose. You will always in your protocol see some secondary purpose such as assessment of safety or something.
Healthy volunteers: Much preferred over patients, if possible. Safer, much easier, fewer AEs. Often a comparison of rate and extent done in volunteers can be extrapolated to patients. Technically, it does not mean rate and extent is the same for a given insulin in patients and in healthy volunteers. Rather it means that if the rate and extent is similar for insulin 1 and insulin 2 in volunteers, then it can quite safely be assume to also be similar in patients.
Fasting: When the subject is fasting as the clamp is started you have much better control over the glucose levels. It can be totally controlled with the glucose infusion. It would be different if one subject has been eating snickers right before dosing. Another subject has been eating something else, but can't remember what it was. A third subject hasn't eaten, and so forth. It is completely standardised when you are using fasting subjects. The only glucose you see in the body is the glucose from the clamp, you can complete keep the subject within a tolerable window.

I could be wrong, but...

Best regards,
ElMaestro

"Pass or fail" (D. Potvin et al., 2008)
VijithRoy
☆    

India,
2020-07-31 07:48
(4 d 05:55 ago)

@ ElMaestro
Posting: # 21811
Views: 159
 

 Good luck :-)

»
» I can't tell from the info you have given what type of study you are doing, but I think you are saying you are comparing two insulins. It sounds like a BE study.
» In that case you are taking blood samples every now and then, probably after the subjects have been given the insulin as an s.c. injection. In these blood samples you measure insulin levels.

Exactly what you said is correct.

our study comparing two insulin products (T/R), two period cross over study with 14 subjects.

Primary parameter - AUC, Cmax (PK) and GIR, GIRmax (PD)
Seconday parameters - ADR, Blood, urine sample test ect,.

10hr fasting before dosing and complete 24hr fasting after dosing till end time point.

nearly 219 blood samples for PD analysis (YSI) and 24 blood (plasma)samples for PK analysis.
Predose collection will be done for 3 samples.

So this is the study goes for each clamp.
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