Thuốc Bortezomib- Velcade
(Because the question was in English, I’ll answer in English first - and
this can be translated to Vietnamese later)
Many thanks for sharing your experience and for your questions.
Unfortunately because of lack of a complete medical records and
particularly also because of medico-legal implications, I will not be able to
present to you my answer specifically about THIS case (note: for these same
reasons, I've therefore declined to render my opinion about specific cases
sent to me via the Internet).
However, in reading your case some thoughts come to mind:
(1) Is bleeding in this case related to Bortezomib?
(2) If not, then what is the mechanism of bleeding in this case ?
Chemotherapy induced bleeding occured infrequently , although
thrombocytopenia is seen commonly in oncology patients. Nadir platelet
count usually appeared from 7-15 days after chemotherapy for other
chemotherapy agents and about day 15 for bortezomib (Ref. : S. Lonial : see
below) (Note: in this case, the first dose of Velcade was given on April 23,
2008 and bleeding appeared on April 27, which is only on day 5).
One may argue that in this specific case, patient had been treated with
other chemotherapy agents (Melphalan) , therefore his bone marrow has
been suppressed and therefore thrombocytopenia appeared earlier. This
assumption may not be correct - because if it is the case, then severe
pancytopenia already had been observed on April 23, 2008 - and this
(pancytopenia) would prevent the oncologist to initiate Velcade on the same
date.
Thrombocytopenia has been associated with Bortezomib (incidence:
24-28%) (S.Lonial et al: "Risk factors and kinetics of thrombocytopenia
associated with bortezomib for relapsed, refractory multiple myeloma"
Blood, 1 Dec 2005, Vol 106, No 12, pp 3777-3784).
The mechnism of thrombocytopenia associated with bortezomib also
was speculated in this article
(http://bloodjournal.hematologylibrary.org/cgi/content/full/106/12/3777)
The authors of this article also noted: "There were no reports of
serious bleeding complications from thrombocytopenia, and platelet
transfusion were required in less than 15% of all patients in this study"
This patient also known to have end-stage renal failure , and on
dialysis - therefore the next question is whether his renal failure
"potentiated" the effect of this agent (bortezomib). A recent article ađressed
this very issue: ẠẠChanan-Khan et al: "Activity and safety of bortezomib in
multiple myeloma patients with advanced renal failure: a multicenter
retrospective study" Blood, 15 March 2007, Vol 109, No 6, pp 2604-2606
(http://bloodjournal.hematologylibrarỵorg/cgi/content/full/109/6/2604). On
table 2 of this article, thrombocytopenia was observed in 7 patients (out of a
total of 39 patients in this review, or an incidence of 39%). Among these 7
patients, servere thrombocytopenia (platelet count less than 25
thousand/mm3) was observed in 2 patients (11%)
Therefore if bleeding in this case is truly from bortezomib, one may
have to look for another mechanism, other than thrombocytopenia- There is
also another possibility: there was NO relation between bleeding - in this
case - and bortezomib. The latter scenario seems to be more likely:
In reading this case, one is struck by the fact that his SGPT (ALT)
was markedly elevated (1000 range) (normal about 40 units/liter - but may
be different at your lab), therefore it is also consistent with a coagulation
disorder from severe liver disease. And THIS coagulation disorder (from
liver failure) is likely the culprit of his bleeding (NOT Bortezomib). To put
in another way, one may speculate that his liver disease had appeared even
BEFORE the initiation of Bortezomib.
Another possibility in this immunocompromized patient is : An
overwhelming infection started first (well known in myeloma , for example
pneumonia). Subsequent sepsis then leads to DIC and patient rapidly
develops multiorgan failure . If it is so, then in this situation, his bleeding is
from DIC (disseminated intravascular coagulation) and its associated severe
thrombocytopenia (and his bleeding is NOT from chemotherapy agents)
In summary, with the data so far, I cannot (at least not yet ) make a
connection between Bortezomib and bleeding disorder in this case.
Again many thanks for your interesting questions,
Nguyễn Tài Mai