Jump to content

workup frequency for Daratumanab


KarenJ

Recommended Posts

   We are getting full genotype on our dara patients before they start on the drug.   Currently we have one patient that requires transfusion and are giving matched blood.  Our question is how often should we send a sample to our reference lab for testing?  There doesn't seem to be a whole lot of agreement on what to do.  Every 72 hours is unrealistic.  Any guidance would be appreciated.   Thanks,  Karen

Link to comment
Share on other sites

Why does every 72 hrs seem unrealistic?  Would you do an antibody screen every 72 hrs?  If yes I don't see that you can treat these pt's any differently.  The pretreatment is not that difficult, only time consuming.  If you have that many pts maybe you should consider bringing it in house.  Just my $0.02 worth.

Link to comment
Share on other sites

I agree with David - DTT-treatment is not difficult and any semi-competent operator should be able to manage it.

"matched blood" can mean many things. If you are supplying red cells matched to avoid immunization to the "common" antigens (Rh[C, E, c, e], S/s, K, Fya/Fyb and Jka/Jkb), one could consider a longer period between testing. Perhaps a policy similar to the way some facilities treat patients with warm autoantibodies? After all, they shouldn't be making any antibodies, in theory. This process doesn't help for antibodies to the lower-incidence antigens, but neither does repeated testing of DTT-treated screening cells.

On another track: In your facility, what percentage of Dara patients need transfusion and how many of those have the reported serological problems ?

Link to comment
Share on other sites

We are a smaller community hospital and do not have dedicated blood bank staff. Generalists rotate through the blood bank.   We are giving blood natched for Rh, K, S/s, Fya/Fyb, and Jka/Jkb.  We were thinking more aling the lines of treating it like a warm.  So far we have had less than 10% of our Dara patients multiply transfused with no known problems to date. 

   

Link to comment
Share on other sites

  • 2 weeks later...

If the patient is k negative based on genotype be sure to be giving k negative units!

 

We only have 1 departmentalized blood banker at the moment and we have brought in DTT testing for these patients. Its MUCH more cost effective to do it in house rather than send out, and if the pt screen is negative well then IS or EXM (K negative or k negative depending on their genotype) is much cheaper than phenotypically matched products!

Link to comment
Share on other sites

2 hours ago, natalynn said:

If the patient is k negative based on genotype be sure to be giving k negative units!

 

We only have 1 departmentalized blood banker at the moment and we have brought in DTT testing for these patients. Its MUCH more cost effective to do it in house rather than send out, and if the pt screen is negative well then IS or EXM (K negative or k negative depending on their genotype) is much cheaper than phenotypically matched products!

I understand your position on (big) K antigen, but how many patients are you treating that are (little) k-negative ? That's a fairly rare phenotype.

Link to comment
Share on other sites

3 minutes ago, exlimey said:

I understand your position on (big) K antigen, but how many patients are you treating that are (little) k-negative ? That's a fairly rare phenotype.

It is, but the k antigen is almost as immunogenic as the K antigen.  Given that patients that are K+k- are going to be very rare, my own thoughts are that giving them K+k- blood from the start is worthwhile, not least because, if they then do not make an anti-k, and need blood as an emergency, they can be given k+ blood to cover the emergency.

This is going to be the official advice in the UK.

Link to comment
Share on other sites

I have been amazed that all of the advice about DARA seems to ignore the rare k neg patient.  If we are going to K type DARA patients, then I think we should k type any who are K pos (or molecular type them from the start).  I have seen a couple of anti-k in my life so maybe I feel that they are more "possible" than some people do.

Link to comment
Share on other sites

16 hours ago, Malcolm Needs said:

It is, but the k antigen is almost as immunogenic as the K antigen.  Given that patients that are K+k- are going to be very rare, my own thoughts are that giving them K+k- blood from the start is worthwhile, not least because, if they then do not make an anti-k, and need blood as an emergency, they can be given k+ blood to cover the emergency.

This is going to be the official advice in the UK.

I wasn't questioning the immunology, merely the fact that the average hospital/blood bank is rarely going to encounter a K+k- patient. If "we" are going be really concerned about k- patients in the Dara scenario, shouldn't "we" also be worried about Kp(b-) and Js(b-) patients ? And what about patient with antibodies to Dombrock system antigens ?

I agree that emphasis on giving K- blood to K- patients is well founded, but it appears that a unduly disproportionate amount of concern is being applied to other, rare blood types. I guess we blood bankers are always looking for zebras ?

Link to comment
Share on other sites

10 hours ago, Mabel Adams said:

I have been amazed that all of the advice about DARA seems to ignore the rare k neg patient.  If we are going to K type DARA patients, then I think we should k type any who are K pos (or molecular type them from the start).  I have seen a couple of anti-k in my life so maybe I feel that they are more "possible" than some people do.

Your point is well taken. My comment above to natalynn was perhaps poorly composed, but your experience emphasizes the point I was trying to make: Many, many, many examples of anti-K will be identified before one anti-k is found. Certainly the rarities should not be ignored, but they should not be the focus of everyday work.

Link to comment
Share on other sites

8 minutes ago, exlimey said:

I wasn't questioning the immunology, merely the fact that the average hospital/blood bank is rarely going to encounter a K+k- patient. If "we" are going be really concerned about k- patients in the Dara scenario, shouldn't "we" also be worried about Kp(b-) and Js(b-) patients ? And what about patient with antibodies to Dombrock system antigens ?

I agree that emphasis on giving K- blood to K- patients is well founded, but it appears that a unduly disproportionate amount of concern is being applied to other, rare blood types. I guess we blood bankers are always looking for zebras ?

In many ways I do agree with what you write, but, however rare K+k- individuals may be, they are considerably more common than are either Kp(b-) and Js(b-) individuals.  It would seem reasonable, therefore, to test for such individuals, in the knowledge that, nationally, and, perhaps, internationally, K+k- blood can be supplied reasonably easily, whereas the search for a reasonable supply of either Kp(b-) or Js(b-) donations could prove fruitless.

Again, with regard to Dombrock antibodies, although undeniably these can be clinically significant, such clinically significant antibodies are incredibly rare - so much so that they are often still written up as posters or abstracts, even in patients who are not on Dara, or similar monoclonal antibody treatment.

Link to comment
Share on other sites

19 minutes ago, Malcolm Needs said:

Again, with regard to Dombrock antibodies, although undeniably these can be clinically significant, such clinically significant antibodies are incredibly rare - so much so that they are often still written up as posters or abstracts, even in patients who are not on Dara, or similar monoclonal antibody treatment.

"Hens' teeth" is a phrase that comes to mind.

Link to comment
Share on other sites

  • 3 weeks later...
On ‎4‎/‎26‎/‎2017 at 2:14 PM, exlimey said:

I understand your position on (big) K antigen, but how many patients are you treating that are (little) k-negative ? That's a fairly rare phenotype.

Exlimey,

Sorry to get back to you so late, but I don’t even know that you need my 2 cense now, everyone seemed to cover my thoughts already.

 

Since (little) k is so rare it will not hurt to check for it on your patients and give (little) k negative units to the few (if any) that are negative for the antigen.

We do a molecular genotype on our Darzalex patients before they receive their first treatment, so we have their K and k results in hand ready if need be.

Link to comment
Share on other sites

Our problem would be to even get the pt phenotyped for k - we don't have the reagent and no other hospital in the area has it.  Also, our local blood distribution system doesn't have it and we will be sending to a reference lab to get the phenotyping anyway.  That said - these pts really worry me.  It is going to hard for us to bring in DTT testing for the few pts we have, (absolutely no idea how many we would get in a year or in the years to come) but I am not happy not being able to see the antibody screen either.  The reference lab that can do the DTT screen - wants to do a full antibody workup everytime they get the pt (not just the DTT screen)- that's expensive!  Still working on the process here. 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Advertisement

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.