Here is the summary of the guidance issued by the
National Institute for Clinical Excellence (NICE) on the use of Glivec
(Imatinib is the chemical name for Glivec).
The NICE recommendations are the numbered paragraphs
and gistsupportUK comments are given as "Translation and Comment"
below
1.1 Imatinib treatment at 400 mg/day
is recommended as the first-line management of people with KIT
(CD117)-positive unresectable and/or KIT (CD117)-positive metastatic
gastro-intestinal stromal tumours (GISTs).
Translation and Comment:
"Unresectable" means
inoperable, "metastatic" means spreading to other areas of the body.
"First line management" means treatment of choice. Obviously if tumours
are operable then the first-line management is surgery to get rid of as
much as possible.
KIT-positive tumours are the most common type of
GIST.
1.2 Continuation with imatinib
therapy is recommended only if a response to initial treatment (as defined
in Section 1.5) is achieved within 12 weeks.
Translation and
Comment:
Treatment with Glivec is to be continued only if the
GIST "responds" within 12 weeks of starting the drug. This is the most
controversial item in the NICE Guidance and is discussed below after
paragraph 1.5
1.3 Responders should be assessed at
intervals of approximately 12 weeks thereafter. Continuation of treatment
in responders to imatinib therapy is recommended at 400 mg/day until the
tumour ceases to respond, as defined in Section 1.5.
Translation and
Comment:
"Responders" are GIST patients for whom the drug
treatment causes shrinkage or disappearance of the tumours or whose
tumours stop growing and become stable. Again the recommendation is that,
if the tumours start to grow again, the treatment should stop. This is a
hard judgement since, if the tumour(s) are inoperable, there is no other
treatment.
1.4 An increase in the dose of
imatinib is not recommended for people receiving imatinib who develop
progressive disease after initially responding (see Section 1.5).
Translation and
Comment:
If a patient stops responding to the drug; i.e. the
tumour(s) start to grow again, increasing the dose of the drug is not
recommended. This is a recommendation which is in dispute and contrary to
the experience of some patients and some oncologists. Latest evidence from
trials of Glivec shows that, in some patients, growth can be stopped by an
increased dose. When all these data are published, this recommendation may
well be dropped.
1.5 For the purpose of this
guidance, response to imatinib treatment should be assessed on the basis
of the results of diagnostic imaging to assess size and density of the
tumour(s), patients' symptoms and other factors, in accordance with the
Southwest Oncology Group (SWOG) criteria detailed in Appendix D. For the
purpose of this guidance, response to therapy is defined as the SWOG
classifications of complete response , partial response or stable
disease.
Translation and
Comment:
"Diagnostic Imaging" means (in the UK) X-ray CT scans.
Appendix D to the report just gives a technical description of the
criteria used. "Complete response" means complete disappearance of the
tumours, "partial response" means shrinkage of the tumours and "stable
disease" means that the tumours stop growing.
The way in which the
tumours respond to Glivec is the all-important matter here. Many
patients' tumours show shrinkage well within the 12-week period, while others may
take many months to respond. Equally important, CT scans can only measure
the size and (less precisely) the density of the tumours. There is a good
deal of evidence that some tumours are "killed" from the inside by Glivec
without changing size and may well become operable if treated for long
enough. These cases would be missed if the 12-week deadline is imposed
strictly. A much better way of judging the response to Glivec is by PET
scanning which measures how active the tumours are by measuring the cell
processes. This type of scan can often show response to Glivec within days
of starting taking the drug. Unfortunately this scanning technique is not
yet widely available in the UK. However, it is to be hoped that, in
allowing "other factors" in the assessment of a patient a more flexible
diagnosis can be given based on an oncologist's experience with each
patient.
1.6 The use of imatinib should be
supervised by cancer specialists with experience in the management of
people with unresectable and/or metastatic GISTs.
Comment:
Seems an obvious
recommendation
Since the NICE Guidance was published, clinical research has moved on in various ways, and we are appealing to the Secretary of State for Health for an urgent review of this Guidance.
(Last updated August 2006)