Note: Descriptions are shown in the official language in which they were submitted.
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TREATMENT OF ACTINIC KERATOSES
_ WITH ALPHA INTERFERON
Summary of the Invention
This invention relates to a method of treating
actinic keratoses with recombinant human alpha interferon
by administering the inter~eron directly into the lesion,
i.e., intralesionally.
In particular, this invention relates to a
specific dosage regimen for administering alpha-2 inter-
feron in the treatment of actlnlc keratoses.
Background
Actinic keratoses represent areas of dysplastic
keratinocytes which develop within the epidermis in
response to chronic exposure to ultravioIet radiation.
These erythematous, scaling lesions are a cosmetic nui-
sance and may cause tenderness or pruritus in some
patients. More importantly, some actinic keratoses pro-
gress into invasive squamous cell carcinomas which not
only are locally destructive but also may rarely
metastasize. Although ther0 are several efficient
methods of removing actinic keratoses, including liquid
nitrogen cryotherapy, topical treatment with 5-
fluorouracil and surgicaI excision, each of these is
destructive. A treatment which could nontraumatically
remove actinic keratoses would be of great benefit to
patients.
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Interferons are a family of proteins which
exhibit antiviral activity against certain viruses and
anticancer activity against certain cancers. There are
three types of interferons: alpha or leukocyte inter-
feron, beta or fibroblast interferon, and gamma or immune
interferon. Human alpha interferon is a naturally
occurring mixture of at least eleven components including
those designated alpha-l interferon and alpha-2 inter-
feron. Human alpha interferon exhibiting biological
properties similar to those of naturally occurring human
leukocyte interferon can be made by recombinant methods.
The anticancer activity of alpha interferon is
based on its anti-proliferative action. It has been
suggested that because interferons possess anti-
proliferative activity, alpha interferon might be useful
in the treatment of proliferative diseases of the skin
such as psoriasis (See K.B. ~ancey and J.G. Smith, Jr.,
"Interferon: Status in treatment of skin disease", Am.
Acad. Dermatol., 3, No. 6 (1980), 585-595), but no report
of the treatment of actinic keratoses has been published.
A number of alpha interferon species or compon-
ents are known and are usually designated by a numeral
after the Greek letter alpha, and all are contempIàted
for use in this invention. Thus, the species designated
human alpha-l interferon and human alpha-2 interferon
(sometimes called human alpha-2b interferon or
abbreviated hIFN-~2; USAN: Interferon Alfa-2b) are
preferred, and human alpha-2 interferon is especially
preferred. Alpha-2 interferon can be produced in
bacteria using recombinant techniques as disclosed by
Rubenstein, ~iochem. BiophYs. Acta, 695, 5-16 (1982). In
addition, alpha-2 interferon may be prepared by
recombinant-DNA methods disclosed by Nagata et_al.,
Nature, 284, 316-320 (1980), in European Patent 32l134,
and in U.S. Patent 4,289,690. Various alpha-2 interferon
species are disclosed in U.S. Patent 4,503,035.
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Detailed Descri~tion
We have found that actinic keratoses favorably
respond to intralesional injections of alpha interferon,
especially alpha-2 interferon, and that this response is
dose-dependent and dose-schedule-dependent. One study
indicates that the concentration of alpha interferon per
dose is a significant factor in the treatment of actinic
keratoses, and a second study indicates that some minimum
dosage is required over a specified period of time.
Following are detailed descriptions of those studies
(i.e., Phase I and Phase II).
Patients and Methods
In Phase I of the study, the dose-dependency of
the therapeutic effect was investigated.
Patients
Sixteen patients each having multiple lesions
were divided into two groups, eight with predominantly
hand and arm lesions, and eight with actinic keratoses of
the face. Within each group, patients were randomly
assigned to one of four treatment groups of two subjects
each. Three typical actinic keratoses which were at
least three centimeters apart from one another were
selected on each subject. These lesions were then
measured, characterized as to degree of erythema and
scale, and photographed as a baseline evaluation before
treatment. Scaling and erythema were quantitated on a
seven-point scale ranging from absent to marked. An
additional one to four actinic keratoses were similarly
evaluated, although not treated, in order to study the
possible systemic effects of intralesional alpha inter-
feron. The patients had received no therapy for their
lesions during the six weeks prior to the study, and none
had reported a history of exposure to radiation, tars,
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arsenic, or immunosuppressive agents. Acetaminophen,
thiazide diuretics and potassium supplements were the
only concomitant medications permitted during the study.
Laboratory Tests
Laboratory monitoring consisted of a pre-
treatment complete blood count with differential and a
platelet count, blood chemistry analysis, and
urinalysis. These were repeated weekly during therapy,
and one week and one month after termination of
therapy. An additional white blood cell count was done
24 hours after the first injection of the test
medication. Serum interferon-neutralizing factor was
assayed before treatment and at one and four weeks after
completion of therapy.
Treatment
Treatments were conducted with reconstituted
solutions of lyophilized human recombinant alpha-2
interferon prepared immediately before injection by the
addition of sterile water and normal saline to the
lyophilizate to obtain the desired doses of 5 x 105
IU/O.lcc, 1 x 105 IU/O.lcc, and 1 x 104 IU/O.lcc.
Treatment consisted of injections of one of the above
doses of interferon or placebo into each of three
designated actinic keratoses three times weekly for three
weeks, for a total of nine injections. Placebo-treated
patients received the same course of~treatment~with O.lcc
injections of sterile water and normal saline. Patients
were observed in the office for thirty minutes after the
injections for symptoms and signs of systemic reactions
to the treatment.
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Response Criteria
The size of the treated and untreated lesions
was measured and compared to the baseline measurement,
and the degree of erythema and scaling was re-evaluated
on the seven-point scale discussed above. Follow-up
evaluations also included a global assessment of changes
in lesion characteristics which was expressed in a six-
point scale ranging from clear to exacerbation.
In Phase II of the study, five different dosing
schedules were evaluated.
Patients
Forty five patients meeting the same criteria
as in Phase I (except that any concommitant medication
not known to interfere with interferon was permitted)
were included. These patients were divided into five
treatment groups.
Laboratory Tests
Same as Phase I.
Treatment
Treatments were conducted with reconstituted
solutions of lyophilized human recombinant alpha-2
interferon. The alpha-2 interferon solutions were
prepared immediately before injection by the addition of
sterile water and normal saline to yield a dose of 5 x
105 IU per O.lcc.
Within each of the five treatment groups, three
patients received placebo, and from five to seven sub-
jects received alpha-2 interferon, 5 x 105 IU per injec-
tion. Each trsatment group was injected according to a
different dosing regimen. These regimens were 1) one
injection per lesion, 2) three injections per lesion in
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one!week, 3) three injections per lesion one week apart,
4) six injections per lesion over two weeks, and 5) nine
injections per lesion over three weeks. Where multiple
injections were given, they were administered every other
day (e.g., Monday, Wednesday and Friday).
Response Criteria
Evaluations of the actinic keratoses and
adverse reactions, as described for Phase I, were carried
out weekly during the treatment phase, and weekly or
bimonthly in the post-treatment phase.
The following Table 1 shows the results of the
dose-dependence study (Phase I).
TABLE 1
Effect of 9 Injections of Alpha-2 Interferon at Variable
Doses on Actinic Keratoses
marked moderate mild
Treatment (75%*) (50%*) (25%*) No
Group Cleared Improvement Improvement Improvement Change
5x105 IU/Inj 11 (92~) 1 (8%)
lx105 IU/Inj 5 (42%) 6 ~50%) 1 t8%)
lx104 IU/Inj 7 (58%) 1 (8%) 2 (17%) 2 (17~)
Placebo 2 (17~) 4 (33%) 2 (17~) 4 (33%)
*percent improvement is measured by reduction in size and scaling
As is apparent from the data in Table 1, the
therapeutic response of actinic keratoses to treatment
with alpha-2 interferon is dose-dependent, that is,
administration of higher doses has a greater therapeutic
effect. Statistically, the difference be-tween the
improvement of the actinic keratoses treated with high
dose alpha-2 interferon and that of the keratoses treated
with placebo was significant at P=0.01.
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The following Table 2 shows the results of the
dosing schedule study.
TABLE 2
Effect of Different Dosing Schedules of Intralesional
Alpha-2 Interferon (5xlO5 IU~ on Actinic Keratoses
Marked Moderate Mild
Treatment Total # (75%*) (50%*) (25%*) No
Lesions Cleared Improvement Improvement Improvement Change
lInj
IFN 18 2 (11%) 5 (28%) 4 (22%) 3 (17%) 4 (22~)
Placebo 9 1 (11%) 7 (78%) 1 (11%)
3Inj/l Wk
IFN 21 10 (48~) 6 (29%) 2 (10%) 1 (5%) 2 (10%)
Placebo 9 2 (20%) 3 (33%) 1 (11%) 3 (33%)
3Inj/3Wks
IFN 18 9 (50%) 3 (17%) 2 (11%) 4 (22%)
Placebo 9 1 (11%) 1 ~11%) 7 (78%)
6Inj/2WXs
IFN 15 14 (93%) 1 (7~)
Placebo 9 5 (56%) 1 (11%) 2 (22%) 1 (11%)
9Inj/3Wks
IFN 15` 7 (47%) 3 (20%) 3 (20%) 2 (13%)
Placebo 9 4 ~44%) 2 (22%) 3 (33%)
*percent improvement is measured by reduction in size and scaling
Inj = Injection(s)
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Table 2 indicates that for a given dosage unit,
i.e.,-5 x 105 IU per injection, different numbers of
injections (i.e., 1, 3, 6 or 9) over different lengths of
time (i.e., once, 3/week, 3/3 weeks, 6/2 weeks and 9/3
weeks) produce different rates of response. Table 2
indicates that one injection is no more effective than
placebo, and that three injections, either in one week or
over three weeks, produce poor response rates. Six
injections over two weeks produce the greatèst response
(93~ cleared), while in contrast to the results in
Table 1, only 47% of the lesions treated with nine
injections over three weeks cleared. While the
discrepancy in the last ~wo results is unexplained at
present, it is clear from the data that at least
3 x 106 IU alpha interferon (i.e., the equivalent of six
injections at 5 x 105 IU each) administered to each
actinic keratosis lesion is necessary to produce a
clinically important effect.
Interferon is able to exert its effects both
locally and systemically. Although some patients did
develop systemic side effects sometimes associated with
intralesional injection of interferon (e.g., local
inflammation, m~algias), the beneficial effects of
intralesional interferon were most likely due to the
local effect of a higher concentration of medication,
since distant actinic keratoses were not significantly
afected.
For intralesional administration, injectable
pharmaceutically acceptable compositions are used. Such
compositions--can, for example, be prepared by diluting
freeze-dried human alpha interferon, preferably alpha-2
interferon, with sterile preservative-free water to
produce an isotonic solution containing the appropriate
concentration of interferon. Other injectable carrier
compositions using saline, aqueous dextrose, glycerol,
ethanol and the like, which yield a solution or
suspension for injection, can also be used. If desired,
minor amounts of nontoxic auxiliary substances such as
wetting or emulsifying agents, preservatives, pH-
buffering agents and the like, for example, sodium
acetate or sorbitan monolaurate, can be incorporated into
the compositions. Actual methods of preparing such
dosage forms are known or will be apparent to those
skilled in this art; see for example, Remington's
Pharmaceutical Sciences, Mack Publishing Company, Easton,
PA, 16th Edition, 1980.
In viaw of the inconvenience attendant upon
treatment with multiple injections (e.g. the
inconvenience of repeated office visits, the discomfort
of the injection procedure), the use of a sustained-
release formulation comprising alpha-2 interferon which
releases the required amount of alpha-2 interferon over
the required time period is a feature of the invention.
Furthermore, the treatment period may yet be reduced when
a sustained release formulation is used since alpha-2
interferon is being constantly administered to the
lesion, as opposed to the intermittant administration of
alpha-2 interferon in the multiple-injection method.
