Antitumor potentiator and antitumor composition

The invention provides; PA0 an antitumor potentiator for potentiating the antitumor activity of an antitumor composition containing tegafur in a therapeutically effective amount and uracil in an amount effective for potentiation of antitumor effect, characterized by containing a folinic acid or a pharmaceutically acceptable salt thereof in an amount effective for potentiation of antitumor effect as an active ingredient; PA0 an antitumor composition characterized by containing tegafur in a therapeutically effective amount, uracil in an amount effective for potentiation of antitumor effect and folinic acid or a pharmaceutically acceptable salt thereof in an amount effective for potentiation of antitumor effect; PA0 a method of potentiating the antitumor effect of an antitumor composition characterized by administering the above antitumor potentiator to a patient; and PA0 a method for therapy of cancer in mammalian animals characterized by administering the above antitumor composition to a patient.

TECHNICAL FIELD 
The present invention relates to an antitumor potentiator, an antitumor 
composition, and the use of them. 
BACKGROUND ART 
Much research and development work about antitumor agents have been made 
and clinically various excellent antitumor agents are in use for the 
chemotherapy of malignant tumors. The outcomes of such therapies have been 
improved year after year but the efficacies are only transitory in many 
instances and are not necessarily sufficient to arrest growth of tumors 
and assure patients of long life spans. By way of illustration, tegafur is 
a substance which is activated in the living body to release 
5-fluorouracil (hereinafter referred to as 5-FU), the substance of its 
antitumor activity, and was designed to alleviate the toxicity or adverse 
effect of 5-FU. The advent of a combination drug consisting of tegafur and 
uracil is predicated on the idea that while 5-FU is rapidly metabolized 
and loses its activity in the body, this inactivation is inhibited by 
uracil which has no antitumor activity of its own to thereby achieve a 
marked potentiation of the antitumor effect. 
However, the current status of cancer therapy points to the need for 
development of drugs having higher antitumor activity. 
DISCLOSURE OF THE INVENTION 
Under the circumstances the inventors of the present invention were 
energetically engaged in the research for enhancing the antitumor effect 
of the tegafur-uracil combination drug and found that the use of folinic 
acid which has no antitumor activity of its own in combination with a 
tegafur-uracil combination drug results in a marked potentiation of the 
antitumor effect of the combination drug without increasing its toxicity 
(particularly digestive organ toxicity). The present invention has been 
developed on the basis of the above finding. 
Thus, the present invention provides an antitumor potentiator for 
potentiating the antitumor activity of an antitumor composition containing 
tegafur in a therapeutically effective amount and uracil in an amount 
effective for potentiation of antitumor effect, the potentiator being 
characterized by containing folinic acid or a pharmaceutically acceptable 
salt thereof in an amount effective for potentiation of antitumor effect 
as an active ingredient, and 
an antitumor composition characterized by containing tegafur in a 
therapeutically effective amount, uracil in an amount effective for 
potentiation of antitumor effect and folinic acid or a pharmaceutically 
acceptable salt thereof in an amount effective for potentiation of 
antitumor effect. 
The antitumor potentiator of the present invention is capable of 
potentiating the antitumor effect of the known tegafur-uracil combination 
drug without increasing its toxicity (particularly digestive organ 
toxicity). 
Tegafur is a drug which is activated in the body to release 5-FU, the 
substance of its activity, and is a known compound. 
Tegafur is produced by the known production technology, for example by the 
process described in Japanese Examined Patent Publication No. 10510/1974. 
On the other hand, uracil has no antitumor activity of its own but 
inhibits the metabolic inactivation of 5-FU in the body to markedly 
potentiate its antitumor effect. 
Therefore, the present invention provides 
a method for therapy of cancer in mammalian animals comprising 
administering to a mammalian animal tegafur in a therapeutically effective 
amount, uracil in an amount effective for potentiation of antitumor effect 
and folinic acid or a pharmaceutically acceptable salt thereof in an 
amount effective for potentiation of antitumor effect and 
a method for further potentiating the antitumor effect resulting from 
administration of an antitumor composition for mammalian animals 
containing tegafur in a therapeutically effective amount and uracil in an 
amount effective for potentiation of antitumor effect to a patient with 
cancer responsive to 5-fluorouracil therapy, the method being 
characterized by administering folinic acid or a pharmaceutically 
acceptable salt thereof in an amount effective for potentiation of 
antitumor effect to the same patient. 
The proportions of tegafur and uracil in the antitumor combination drug to 
be used in conjunction with the antitumor potentiator of the present 
invention may be the same as that used in the known combination drug. 
Thus, based on each mole of tegafur, the proportion of uracil is generally 
0.02 to 10 moles and preferably 0.1 to 10 moles. 
Folinic acid which is used in the antitumor potentiator of the present 
invention has heretofore been used chiefly for the purpose of mitigating 
the toxicity of folic acid antagonists and no antitumor action has been 
reported in this compound as such. Folinic acid exists in d- or l- form as 
optical isomer and any of these isomers as well as mixture thereof can be 
employed in the present invention. The use of the l-isomer or a mixture of 
l- and d-isomers is particularly beneficial. The pharmaceutically 
acceptable salt of folinic acid includes, for example, the corresponding 
calcium salt. 
While the proper proportion of folinic acid or a salt thereof varies 
according to clinical requirements and is not specifically limited, it is 
generally 0.05 to 10 moles and preferably 0.1 to 5 moles per mole of 
tegafur. 
The antitumor potentiator of the present invention can be independently 
processed into various dosage forms and administered either independently 
of or simultaneously with the tegafur-uracil combination drug which may 
also have been processed into various dosage forms. Thus, the antitumor 
potentiator can be administered any time before, after or simultaneously 
with the administration of the tegafur-uracil combination drug. 
Preferably, it is administered simultaneously or within 4 hours and more 
preferably 2 hours before or after administration of the tegafur-uracil 
combination drug. 
In the present invention, an antitumor potentiator-containing antitumor 
composition can be provided by incorporating folinic acid or a salt 
thereof in a tegafur-uracil combination drug. This antitumor composition 
can be processed into various dosage forms and administered. In such 
cases, the proportions of tegafur, uracil and folinic acid or a salt 
thereof may be the same as mentioned above, i.e. 0.02 to 10 moles, 
preferably 0.1 to 10 moles, of uracil and 0.05 to 10 moles, preferably 0.1 
to 5 moles, of folinic acid or a salt thereof based on each mole of 
tegafur. 
The present invention provides, as mentioned above, a mixed pharmaceutical 
composition containing an antitumor potentiator comprising folinic acid or 
a salt thereof in combination with a tegafur-uracil combination drug or a 
pharmaceutical composition comprising said antitumor potentiator and said 
tegafur-uracil combination drug as two independent units. Either of these 
compositions can be manufactured by the conventional method using a 
suitable pharmaceutical carrier. The carrier for this purpose may include 
those widely used for common pharmaceuticals, such as excipients, binders, 
disintegrators, lubricants, colorants, corrigents, flavors, surfactants 
and so on. 
Furthermore, the above antitumor potentiator and the tegafur-uracil 
combination drug can be provided in the form of a kit comprising a 
combination of the following pharmaceutical compositions for therapy of 
cancer in mammalian animals, namely 
(a) an antitumor composition containing tegafur in a therapeutically 
effective amount and uracil in an amount effective for potentiation of 
antitumor effect, and 
(b) a composition containing folinic acid or a pharmaceutically acceptable 
salt thereof in an amount effective for potentiation of the antitumor 
effect of said antitumor composition. 
In this kit, the respective constituent compositions can be provided in 
optional known dosage forms and generally these compositions are 
accommodated in appropriate containers selected according to particular 
dosage forms. 
Moreover, this kit may be a kit for therapy of cancer in mammalian animals 
which comprises at least three components and at least two containers for 
said components, said three components comprising: 
(i) tegafur in a therapeutically effective amount, 
(ii) uracil in an amount effective for potentiation of antitumor effect, 
and 
(iii) folinic acid or a pharmaceutically acceptable salt thereof in an 
amount effective for potentiation of the antitumor effect of the above 
antitumor composition, 
said tegafur and said folinic acid or salt thereof being packaged in 
different containers. 
The respective components of the kit of the invention can be administered 
simultaneously or one before or after the other at an appropriate 
interval. Preferably, they are administered concurrently or one within 4 
hours, preferably 2 hours, before or after administration of the other. 
According to the kit of the present invention, the antitumor effect of the 
antitumor composition containing tegafur and uracil is remarkably enhanced 
by the composition containing folinic acid or a pharmaceutically 
acceptable salt thereof without increasing the level of toxicity such as 
digestive organ toxicity. 
There is no limitation on the unit dosage form which can be adopted for the 
antitumor potentiator or antitumor composition of the invention in the 
treatment of malignant tumors in mammalian animals inclusive of human 
beings. Thus, optional unit dosage forms can be selected according to the 
purpose of treatment. Thus, for example, various non-oral dosage forms 
such as injections, suppositories, ophthalmic solutions, ointments, 
aerosols, etc. and various oral dosage forms such as tablets, coated 
tablets, powders, granules, capsules, solutions, pills, suspensions, 
emulsions, etc. can be mentioned. These dosage forms can be manufactured 
by the pharmaceutical procedures well established in this field. 
As the carrier for the manufacture of solid dosage forms for oral 
administration, such as tablets, powders, granules, etc., there can be 
employed various excipients such as lactose, sucrose, sodium chloride, 
glucose, urea, starch, calcium carbonate, kaolin, crystalline cellulose, 
silicic acid, methylcellulose, glycerol, sodium alginate, gum arabic, 
etc.; binders such as simple syrup, glucose solution, starch solution, 
gelatin solution, polyvinyl alcohol, polyvinyl ether, 
polyvinylpyrrolidone, carboxymethylcellulose, shellac, methylcellulose, 
ethylcellulose, water, ethanol, potassium phosphate, etc.; disintegrators 
such as dry starch, sodium alginate, agar powder, laminaran powder, sodium 
hydrogen carbonate, calcium carbonate, polyoxyethylene-sorbitan fatty acid 
esters, sodium lauryl sulfate, stearic acid monoglyceride, starch, 
lactose, etc.; antidisintegrators such as sucrose, stearic acid, cacao 
butter, hydrogenated oil, etc.; absorption promotors such as quaternary 
ammonium bases, sodium lauryl sulfate, etc.; humectants such as glycerol, 
starch, etc.; adsorbents such as starch, lactose, kaolin, bentonite, 
colloidal silicic acid, etc.; and lubricants such as purified talc, 
stearic acid salts, boric acid powder, polyethylene glycol and so on. The 
tablets may be coated, where necessary, to provide sugar-coated tablets, 
gelatin-coated tablets, enteric-coated tablets, film-coated tablets, 
double or multi-layer tablets and so on. 
The carrier for shaping into the form of pills includes, for example, 
various excipients such as glucose, lactose, starch, cacao butter, 
hardened vegetable oil, kaolin, talc, etc.; binders such as gum arabic 
powder, gum tragacanth powder, gelatin, etc.; and disintegrators such as 
laminaran, agar and so on. 
Capsules are manufactured by mixing the antitumor potentiator, either alone 
or together with a tegafur-uracil combination drug, with any of the 
carriers mentioned above and filling the mixture in hard gelatin capsule, 
soft capsule or other capsules. 
The carrier for shaping into the form of suppositories include, for 
example, polyethylene glycol, cacao butter, lanolin, higher alcohols, 
esters of higher alcohol, gelatin, semi-synthetic glycerides, Witepsol 
(Resistered trademark for the product of Dynamit Nobel) and so on. 
The carrier for shaping into the form of injections includes, for example, 
various diluents such as water, ethyl alcohol, macrogols, propylene 
glycol, ethoxylated isostearyl alcohol, polyoxylated isostearyl alcohol, 
polyoxyethylene-sorbitan fatty acid esters, etc.; pH control agents and 
buffers such as sodium citrate, sodium acetate, sodium phosphate, etc.; 
and stabilizers such as sodium pyrosulfite, EDTA, thioglycollic acid, 
thiolactic acid and so on. In these injections, it is allowable to 
incorporate sodium chloride, glucose or glycerol in an amount sufficient 
to provide an isotonic solution or to add the conventional solubilizer, 
soothing agent local anesthetic or the like. After addition of these 
carriers, injections for subcutaneous, intramuscular or intravenous 
administration can be manufactured by the established procedures. 
The liquid dosage form includes aqueous or oily suspensions, solutions, 
syrups, elixirs, etc. and can be manufactured by the established 
pharmaceutical procedures using the usual additives. 
The diluent for the manufacture of ointments, such as pastes, creams, gels, 
etc., includes, for example, white petrolatum, paraffin, glycerol, 
cellulose derivatives, polyethylene glycol, silicon compounds, bentonite 
and so on. 
The amount of folinic acid or a pharmaceutically acceptable salt thereof, 
which is the active ingredient of the antitumor potentiator of the present 
invention, or the amounts of tegafur, uracil and folinic acid or a 
pharmaceutically acceptable salt thereof, which are the active ingredients 
of the antitumor composition of the invention, are dependent on the dosage 
form, route of administration, dosing schedule, etc. and can be 
appropriately chosen. Generally, however, the total amount of active 
substance or substances in the dosage form may range from about 1 to about 
70 percent by weight. 
The route of administration of the antitumor potentiator or antitumor 
composition of the present invention may for example be intestinal, oral, 
rectal, stomatic, percutaneous or the like and can be freely selected 
according to the dosage form, the patient's age, sex and other factors, 
the clinical condition of the patient and so on. By way of example, 
tablets, pills, solutions, suspensions, emulsions, granules and capsules 
are orally administered. Suppositories are inserted into the rectum. 
Ointments are applied to the skin, the intraoral mucosa or the like. 
In the present invention, the dosage of each active ingredient in each 
pharmaceutical composition can be selected according to the method of 
administration, the patient's age, sex and other factors, the degree of 
disease and so on. In the case of oral administration, the standard dosage 
is about 0.1 to 100 mg/kg/day, preferably about 1 to 30 mg/kg/day, for 
tegafur, about 0.1 to 100 mg/kg/day, preferably 1 to 50 mg/kg/day, for 
uracil and about 0.1 to 500 mg/kg/day, preferably 0.2 to 300 mg/kg/day, 
for folinic acid or a pharmaceutically acceptable salt thereof. The 
compositions of the invention can each be administered daily in a single 
dose or in 2 to 4 divided doses. In the case of injections, e.g. 
intravenous injections, the equivalent of, generally, about 1 to 50 mg/kg 
of tegafur per day per adult is optionally diluted with physiological 
saline or glucose injection and is administered gradually over a period of 
not less than 5 minutes. In the case of suppositories, the equivalent of 
about 1 to 100 mg/kg of tegafur per adult is administered into the rectum 
once to twice a day at an interval of 6 to 12 hours. 
The malignant tumors which can be treated with the compositions of the 
invention may be any of the tumors responsive to 5-fluorouracil which is 
the active substance. Among them are cancers of the head and neck, 
stomach, colon, rectum, liver, gallbladder-bile duct, pancreas, lung, 
breast, urinary bladder, prostate, uterine cervix and so on. Particularly 
high success rates can be expected in colon cancer, rectal cancer and 
mammary cancer.

EXAMPLES 
Some formulation examples of the antitumor potentiator of the invention and 
some formulation examples of the antitumor composition with the antitumor 
potentiator of the invention are presented below as examples of the 
invention. 
Formulation Example 1 
______________________________________ 
Folinic acid 100 mg 
Lactose 170 mg 
Crystalline cellulose 
77 mg 
Magnesium stearate 
3 mg 
350 mg per capsule 
______________________________________ 
Using the established pharmaceutical procedure, capsules were prepared 
according to the above formula. 
Formulation Example 2 
______________________________________ 
Calcium folinate 200 mg 
Lactose 340 mg 
Corn starch 450 mg 
Hydroxypropylmethylcellulose 
10 mg 
Granules 1,000 mg 
______________________________________ 
Using the established pharmaceutical procedure, granules were prepared 
according to the above formula. 
Formulation Example 3 
______________________________________ 
Folinic acid 500 mg 
Lactose 240 mg 
Corn starch 250 mg 
Hydroxypropylmethylcellulose 
10 mg 
Fine granule 1,000 mg 
______________________________________ 
Using the established pharmaceutical procedure, fine granules were prepared 
according to the above formula. 
Formulation Example 4 
______________________________________ 
Folinic acid 50 mg 
Lactose 90 mg 
Crystalline cellulose 
30 mg 
Magnesium stearate 2 mg 
Talc 3 mg 
Hydroxypropylmethylcellulose 
10 mg 
185 mg per tablet 
______________________________________ 
Using the established pharmaceutical procedure, tablets were prepared 
according to the above formula. 
Formulation Example 5 
______________________________________ 
Calcium folinate 200 mg 
Distilled water for injection 
g.s. 
5 ml per ampule 
______________________________________ 
Using the established pharmaceutical procedure, an injection was prepared 
according to the above formula. 
Formulation Example 6 
______________________________________ 
Tegafur 50 mg 
Uracil 112 mg 
Folinic acid 250 mg 
Lactose 280 mg 
Corn starch 298 mg 
Hydroxypropylmethylcellulose 
10 mg 
1,000 mg per wrapper 
______________________________________ 
Using the established pharmaceutical procedure, granules were prepared 
according to the above formula. 
Formulation Example 7 
______________________________________ 
Tegafur 50 mg 
Uracil 112 mg 
Calcium folinate 
75 mg 
Lactose 103 mg 
Crystalline cellulose 
57 mg 
Magnesium stearate 
3 mg 
400 mg per capsule 
______________________________________ 
Using the established pharmaceutical procedure, capsules were prepared 
according to the above formula. 
Formulation Example 8 
______________________________________ 
Tegafur 25 mg 
Uracil 56 mg 
Calcium folinate 25 mg 
Lactose 52 mg 
Crystalline cellulose 
15 mg 
Magnesium stearate 3 mg 
Corn starch 14 mg 
Hydroxypropylmethylcellulose 
10 mg 
200 mg per tablet 
______________________________________ 
Using the established pharmaceutical procedure, tablets were prepared 
according to the above formula. 
Formulation Example 9 
______________________________________ 
Tegafur 200 mg 
Uracil 448 mg 
Folinic acid 500 mg 
Witepsol W-35 
852 mg 
2,000 mg per suppository 
______________________________________ 
Using the established pharmaceutical procedure, suppositories were prepared 
according to the above formula. 
EXAMPLE 1 
A 2 mm-diameter fragment of mouse colon cancer line COLON 26 was 
subdermally transplanted at the back of male CDF.sub.1 mice. Beginning 24 
hours after transplantation of the tumor fragment, a solution or 
suspension of tegafur-uracil combination drug, 5-fluorouracil and calcium 
folinate, the amounts of which are indicated below in Table 1, in 0.5% 
sodium calboxymethylcellulose (CMC) solution was administered orally once 
a day for 9 consecutive days. On day 12 after transplantation of the 
tumor fragment, the tumor was enucleated and weighed. From the ratio of 
the mean tumor weight in each treatment group to that in the control 
group, the tumor growth inhibition rate was calculated. On the other hand, 
the body weight of mice on the day of tumor fragment transplantation was 
subtracted from the body weight of mice exclusive of tumors on day 12 
after transplantation and the difference was used as the index of 
drug-induced systemic toxicity. Furthermore, the stools passed by mice in 
each treatment group were examined daily and, in accordance with the 
method described in Japanese Journal of Cancer Research Vol. 81, 188-195 
(1990), the stool property was rated on the following scale: -: normal 
stool (hard pellets with little moisture), .+-.: loose stool (normal form, 
moist and soft), +: loose stool (undefinable form, very moist and soft), 
++: diarrheal stool (formless, watery). 
The results are set forth in Table 1. 
TABLE 1 
__________________________________________________________________________ 
Folinic 
Tumor Growth 
Change in 
Dosage 
acid inhibition 
body weight 
Stool 
Drug (mg/kg) 
(mg/kg) 
rate (%) 
(g) property 
__________________________________________________________________________ 
Tegafur + uracil 
20.0 + 44.8 
0 45 +1.8 .+-. 
Tegafur + uracil 
20.0 + 44.8 
100 79 +1.5 .+-. 
Tegafur + uracil 
15.0 + 33.6 
0 43 +1.9 .+-. 
Tegafur + uracil 
15.0 + 33.6 
100 65 +1.6 .+-. 
5-Fluorouracil 
20.0 0 43 +1.7 .+-. 
5-Fluorouracil 
20.0 100 56 +0.1 ++ 
__________________________________________________________________________ 
EXAMPLE 2 
A 2-3 mm-diameter fragment of mouse colon cancer line COLON 38 was 
subdermally transplanted at the back of 6-week-old male BDF.sub.1 mice and 
the mice in which the tumor volume (major diameter.times.minor 
diameter.sup.2 /2) had reached 100-200.sup.3 mm were used in groups each 
consisting of 7 in the following experiment. 
The mice were dosed orally with a solution or suspension of tegafur-uracil 
combination drug and calcium folinate, the amounts of which are indicated 
below in Tables 2 and 3, in 0.5% sodium carboxylmethylcellulose (CMC) 
solution once a day for 9 consecutive days. 
The antitumor efficacies were evaluated as follows. Using a pair of 
calipers, the tumor volume was measured serially and the tumor growth 
inhibition rate was calculated from the ratio of the mean tumor volume in 
each treatment group to that in the control group. On the other hand, the 
body weight of mice on the day of tumor fragment transplantation was 
subtracted from the body weight of mice exclusive of tumors on day 10 
after transplantation and the difference was used as the index of 
drug-induced systemic toxicity. 
The results are set forth in Tables 2 and 3. 
TABLE 2 
__________________________________________________________________________ 
Folinic 
Tumor Growth 
Change in 
Dosage acid inhibition 
body weight 
Drug (mg/kg) 
(mg/kg) 
rate (%) (g) 
__________________________________________________________________________ 
Tegafur + uracil 
20.0 + 44.8 
0 76 +0.3 
Tegafur + uracil 
20.0 + 44.8 
100 98 +0.6 
__________________________________________________________________________ 
TABLE 3 
______________________________________ 
Tumor Growth 
Dosage Folinic acid 
inhibition 
Drug (mg/kg) (mg/kg) rate (%) 
______________________________________ 
Tegafur + uracil 
20.0 + 44.8 
0 79 
Tegafur + uracil 
20.0 + 44.8 
6.7 94 
Tegafur + uracil 
20.0 + 44.8 
25 90 
Tegafur + uracil 
20.0 + 44.8 
67 91 
Tegafur + uracil 
20.0 + 44.8 
100 94 
Tegafur + uracil 
20.0 + 44.8 
167 91 
Tegafur + uracil 
20.0 + 44.8 
250 93 
______________________________________ 
EXAMPLE 3 
A 2-3 mm-diameter fragment of human colon cancer line KM20C was subdermally 
transplanted at the back of 6-week-old female BALB/c-nu/nu mice and the 
mice in which the tumor volume (major diameter.times.minor diameter.sup.2 
/2) had reached 100-200 mm.sup.3 were used in groups each consisting of 7 
in the following experiment. 
The mice were dosed orally with a solution or suspension of tegafur-uracil 
combination drug and calcium folinate, the amounts of which are indicated 
below in Table 4, in 0.5% sodium carboxymethylcellulose (CMC) solution 
once a day for 10 consecutive days. 
The antitumor efficacies were evaluated as follows. Using a pair of 
calipers, the tumor volume was measured serially and the tumor growth 
inhibition rate was calculated from the ratio of the mean tumor volume in 
each treatment group to that in the control group. On the other hand, the 
body weight of mice on the day of tumor fragment transplantation was 
subtracted from the body weight of mice exclusive of tumors on day 12 
after transplantation and the difference was used as the index of 
drug-induced systemic toxicity. 
The results are set forth in Table 4. 
TABLE 4 
__________________________________________________________________________ 
Folinic 
Tumor Growth 
Change in 
Dosage acid inhibition 
body weight 
Drug (mg/kg) 
(mg/kg) 
rate (%) (g) 
__________________________________________________________________________ 
Tegafur + uracil 
20.0 + 44.8 
0 3 -0.3 
Tegafur + uracil 
20.0 + 44.8 
100 36 -0.5 
__________________________________________________________________________