2
BioTech Stock Report, March 2003
mate that the current costs of MS total
greater than $25 billion per year. The
economic costs of MS include both
direct health care costs (for drugs,
physician services, and hospitaliza-
tion) and indirect costs (for lost worker
productivity). Patients' inability to
move freely and to perform everyday
tasks restricts their independence and
leads to increased reliance on caregiv-
ers and assistive devices. Emotional
and psychosocial well-being is also
negatively affected, further compound-
ing the gravity of the situation.
What causes MS?
Although it is widely agreed upon
that MS is an autoimmune disease, the
factors associated with the induction
of disease are still unknown. Studies
indicate that genetic factors make cer-
tain individuals more susceptible than
others, but there is no evidence that
MS is directly inherited. Medical re-
searchers are constantly exploring the
possibility that an infectious agent
may be associated with the initiation of
the disease and much research has
focused to address this question. Vi-
ruses are high on the list of agents as
some viruses can cause demyelinating
disease in animals and humans. No
virus has been linked yet, which is
good, as a viral origin would suggest
that MS is contagious, which it is not.
Interestingly, one virus, human her-
pesvirus type 6 (HHV6) is still being
considered as a cofactor, as the virus
has been found to be present in MS
lesions of most patients. However,
given the fact that greater than 90% of
the adult population in the world is
infected with HHV6, its role in MS is
suspect.
Types of MS
Approximately, 80% of MS affect-
ing the patient population is the re-
lapsing-remitting form of MS (RRMS).
The distinguishing characteristics of
RRMS that differentiates it from the
other forms are the temporary symp-
toms flare-ups, which last for one to
three months and are followed by a
complete or partial recovery that may
last for more than a year. While symp-
toms associated with MS may not
worsen between attacks, damage to
the CNS can occur, which can accumu-
latively lead to disability.
If left untreated, more than 90% of
individuals with RRMS eventually pro-
gress to a second phase, known as
secondary progressive MS (SPMS),
which can occur within 25 years. This
phase is reached when the patient ex-
periences a progressive worsening of
symptoms.
Some 20% of individuals with MS
have primary progressive MS (PPMS).
This form of MS is associated with a
gradual and steady accumulation of
neurological problems from the onset
of the disease without the relapses and
remissions observed in RRMS.
Current therapies for MS
With the understanding of MS
disease course, current MS treatments
NAME
PERCENT
OF
PATIENTS
CHARACTERISTICS
RRMS (Relapsing
Remitting MS)
80
Symptom flare-ups followed by
recovery; stable between attacks.
SPMS (Secondary-
Progressive MS)
90% of RRMS
Second phase of RRMS; progressive
worsening of symptoms with or with-
out superimposed relapses; treatments
may delay or prevent this phase.
PPMS (Primary-
Progressive MS)
<20
Gradual but steady accumulation of
neurological problems from onset.
Benign
<1
Few attacks and little or no disability
after 20 years.
PRMS
(Progressive
Relapsing MS)
<1
Progressive course from the onset,
sometimes combined with occasional
acute symptom flare up.
Malignant or
fulminant MS
<1
Rapidly progressive disease course.
TYPES OF MULTIPLE SCLEROSIS
