What happen to extra dose of Herceptin or CanMab

[Payal108]

These medicines come as a pack of 440mg, normally a patient take 6mg/kg ~ 330mg. What happens to  extra medicine? One Doctor I consulted calculated total medicine requirement as 1 + (330 * 16)/440, considering left over from previous cycle can be used in next cycle, as self life of prepared medicine is 4 weeks.

Is this practice common? If no, what happens to extra medicine?

Thanks

[roxboxfox RadiationOncologist]

It's very difficult to know the efficacy of the medication post 3 weeks.

Its like If I save some water store it in fridge and use it 3 weeks later..would it be alright. For Indians living in drought, even a drop saved is precious.

But in western world ppl would not advocate this for obvious concerns.

So the answer is if u can't afford the entire years course if Herceptin, then u may try to Save little bit of Herceptin and use it...who knows about its efficacy....

But if u wanted things to go like Mr Perfect...then u would nt be storing Herceptin.

I would say this is not so common

[Payal108 in reply to roxboxfox]

Thanks, 

It does not require storing for more then 4 weeks, only for 3 weeks.  As medication from last cycle get used first and remaining from new vile stored for next cycle.  

CanMab packaging mentions 

1) "Multi-use vial for i.v. infusion, Lyophilised powder"

2) Do not freeze reconstituted solution & use the solution within 28 days after reconstitution.

I see similar information about Herceptin (@ globalrph.com/trastuzumab.htm) , another related link ( racmonitor.com/rac-enews/15... 

I have talked to one of the employee in field function related to this medicine, he says it is common practice.

[roxboxfox RadiationOncologist in reply to Payal108]

You are right !

Vials of Herceptin are stable at 2–8°C (36–46°F) prior to reconstitution. Do not use beyond the expiration date stamped on the vial. A vial of Herceptin reconstituted with BWFI, as supplied, is stable for 28 days after reconstitution when stored refrigerated at 2–8°C (36–46°F). Discard any remaining multi-dose reconstituted solution after 28 days. A vial of Herceptin reconstituted with unpreserved SWFI (not supplied) should be used immediately and any unused portion discarded. Do Not Freeze Herceptin following reconstitution or dilution. The solution of Herceptin for infusion diluted in polyvinylchloride or polyethylene bags containing 0.9% Sodium Chloride Injection, USP, should be stored at 2–8°C (36–46°F) for no more than 24 hours prior to use.

 If Herceptin is reconstituted with SWFI without preservative, use immediately and discard any unused portion.

The key is you have to hope the nurse or doctor reconstitutes with BWFI and not with SWFI ! ! !

[Payal108 in reply to roxboxfox]

Thanks,   My worries are same, if it normal practice hospital will have process, staff will have understanding  how to make use of Multi-use vial by proper tagging and storage. If not, it is tricky ..