Reprinted from CANCER. VoL 64. No. 8. Catch I5. I989.
`Correr 0 I989. by the America Canoe Sodety, Inc. J. B. [imam Company.
`Printed in USA.
`
`Evaluation of Antitumor Activity in a Human Breast
`
`Tumor/Nude Mouse Model With a Special
`
`Emphasis on Treatment Dose
`
`MAKOTO INABA. PHD.‘ TOMOWO KOBAYASHI. PHD.‘ TAZUKO TASHIRO. PHD.‘ YOSHIO SAKURAI. PHD.’
`KOJI MARUO. PHD.1' YASUYUKI OHNISHI. VMD.1' YOSHITO UEYAMA. MD.1' AND TATSUJI NOMURA. MD‘I’
`
`Eight lines of human breast tumors implanted in nude mice were treated with various antitumor agents
`at two different doses. maximum talented doses (MTD) and rational doses (RD) that were pharmacoki-
`netically equivalent to the clinical doses; the response rates to both doses were compared. With MTD,
`the response rates to mitomycin C and vIanastine were I00%, and those to other agents including cyclo-
`phosphamide, nimustine (a water-soluble nitrosourea), vincrisitine, Adriamycin (doxorubicin; Adria Lab-
`oratories, Columbus. OH), 5-fluorouracil (S-FU), and methotrexate were 3095—5095, indicat'mg high re-
`sponsiveness to the former two agents. In contrast, when the RD were used. the response rates to the
`Mority of these agents were 255-401;. and those to vinaistine and nimustine were I3% and 0%, re-
`spectively. These results agree with the reported clinical results compared with those with M11). suggesting
`the importance of the use of clinically equivalent doses in the evaluation of antitumor eilicacy in a human
`tumor/nude mouse system.
`
`Cancer 64:I577—IS82. I989.
`
`ANY STUDIES on the evaluation ofantitumor agents
`by a human tumor/nude mouse model have been
`reported currently. However. those evaluations were not
`necessarily satisfactory in terms of reproducibility or pre-
`dictability of clinical effects despite the use of human tu-
`mors as a target. There seem to be two reasons for this
`correlation. One is inappropriateness of the therapeutic
`dose used. To gain the maximum effect. mice are usually
`treated at maximum tolerated dose (MTD). However,
`MTD per body weight of most antitumor agents for nude
`
`From 'Cancer Chemotherapy Center, Japanme Foundation for Cum
`Resnrch. Tokyo. and tCentral Institute for Experimental Animals. Ka-
`wasaki, Japan.
`Supported in part by Grants-in-Aid for New Drug Development Re-
`search from the Ministry of Health and Welfare. Japan.
`The authors thank Ms. Reiko Emura, Michiyo Kuwabara. and Mr.
`Shim Sato for their technical assistance. S-Fluorouracil. mitomycin C.
`and Adriamycin were supplied by Kyowa Hakko Kogyo Co.. Tokyo.
`Japan. Cyclophosphamide and nimustine were provided by Shionogi 5L
`Co. and Sankyo Co., Ltd.. Tokyo. Japan. respectively. MX-l line was
`supplied by the Mammalian Genetics and Animal Production Section.
`Divion of Cancer Treatment. National Institutes of Health. Bethesda.
`MD. The MMKY line was supplied by Dr. T. Hanori. Hiroshima Uni-
`versity. Hiroshima; H-3l
`line. by Dr. T. Taguchi. (halo University,
`Osaka; and Br-lO line. by Dr. T. Kubota. Kdo University. Tokyo. Japan-
`Other lines were established by the Central Institute for Experimental
`Animals.
`Address for reprints: Makoto Inaba. PhD. Cancer Chemotherapy
`Center. Japanese Foundation for Cancer Research. Kami-Ikebukuro.
`Toshima-ku. Tokyo I70. Japan.
`Accepted for publication April 20. I989.
`
`mice are greater than clinical doses. Pharmacokinetic
`characteristics are also different between humans and
`
`mice. Therefore. the concentration of antitumor agents
`in the blood seem to be greatly different between humans
`and nude mice under the therapeutic condition. This sug-
`gested that the effects of therapy for most antitumor agents
`tend to be overestimated in the nude mouse model com-
`
`pared with clinical eflicacy. Another reason concerns the
`number of tumor strains used. Drug sensitivity varies
`among tumors of the same kind. This indicates that testing
`ofone or a few tumor strains might not provide the correct
`evaluation of antitumor eflicacy of a given drug against
`a certain type of tumor.
`Based on these considerations. to improve the clinical
`predictability of the human tumor/nude mouse model.
`we have developed a new system for its evaluation in
`which the use of clinically equivalent dose as a therapeutic
`dose and response rate as a measure of evaluation were
`introduced.” To obtain the clinically equivalent dose. we
`did comparative pharmacokinetic studies between hu-
`mans and nude mice to find the dose of a given drug that
`can reproduce in the nude mouse a plasma level similar
`to that seen in human patients treated with an effective
`dose of the drug. We have designated this dose as the
`rational dose (RD).3 In addition, to assess the response
`rate experimentally. our test used as many tumor strains
`of the same kind as possible.
`
`[577
`
`Celltrion v. Genentech
`
`IPR2017—01122
`
`Genentech Exhibit 2019
`
`

`

`l578
`
`CANCER October 15 1989
`
`Vol. 64
`
`
`
`TABLE 1. Profiles on Human Breast Tumor Xenografl Lines
`Tumor mass
`Tumor
`doubling
`Hormone
`
`line
`Histologic type
`time (d)
`receptor
`
`3.7
`Med tubular Adenoca
`MX-l
`“.4
`Med tubular Adenoca
`MC-2
`l 1.8
`Med tubular Adenoca
`MC-S
`l 1.1
`Med tubular Adenoca
`MC-8
`8.l
`Med tubular Adena:
`MC-9
`13.}
`MMKY Med tubular Adenoca
`ER (-)
`6.l
`H-3|
`Papillotubular Adenoca
`
`Br-lO ER (+). PgR (-) Common ductal Adenoca 5.5
`
`
`
`BR (—-). PgR (t)
`ER (—). PgR (—)
`ER (—), PgR (-—)
`'
`
`Med: medullary: Adenoea: adenocaminoma; ER: estrogen receptor.
`PgR: progesterone receptor.
`
`According to this model. we studied previously the re-
`sponsiveness of various antitumor agents to RD and MTD
`'in 11 strains ol‘human gastric tumors implanted in nude
`mice. The results with RD conelated well with the clinical
`
`results compared with those of MTD in respect to their
`relative therapeutic potency.2 In the current study, to ex-
`amine further the validity of our model. we studied the
`comparative responses of various antitumor agents to RD
`and MTD in a panel of human breast tumors implanted
`in nude mice serially.
`
`Materials and Methods
`
`Antilumor Agents
`
`Vinblastine (VLB) and vincristine (VCR) (Shionogi &
`Co.. Osaka, Japan). and methotrexate (MTX, Lederle
`Japan Ltd.. Tokyo. Japan) were purchased for clinical
`use. 5-fluorouracil (S-FU). mitomycin C (MMC), and
`Adriamycin (ADR) were supplied as pure crystals for
`experimental use. Cyclophosphamide (CPM) and nimus-
`tine (ACNU) were previded for experimental use.
`All drugs were dissolved in sterile 0.85% NaCl solution
`before use.
`
`Human Tumor Xenograft Lines
`
`Eight human breast tumors established as xenogral'ts
`in nude mice were used. Their characteristics, including
`histologic type. tumor doubling time, and hormone re-
`ceptor status. are shown in Table I.
`These tumors have been maintained approximately
`every month by serial subcutaneous transplantation of 2
`x 2 X 2 mm cubic fragments in the right subaxillary region
`of athymic BALB/c-nu/nu mice (Clea Japan. lnc., Tokyo,
`Japan). Mice bearing Br-lO were injected in the femoral
`region within one week afier transplantation with .l ml
`of a solution containing 50 mg hydroxyprogesterone cap-
`
`roate and 1 mg estradiol dipropionate (E.P. Hormonell
`Depot, Teikoku Hormone Mfg. Co.. Ltd.. Tokyo, Japan).
`Mice were housed in ethylene oxide-sterilized, filter-
`capped cages with 5°Co-irradiated (3—megarad) food and
`autoclaved water ad Iibimm. All cages were kept in lam-
`inar-air-flow units in our laboratory. Female mice that
`were 6 to 8 weeks of age and weighed about 25 g were
`used.
`
`Measurement of Tumor Size
`
`After the transplantation, the mice were observed and
`segregated randomly into several experimental groups,
`which consisted of six animals each, after the tumors had
`reached palpable size. The tumor volume (V) was cal-
`culated by the equation
`
`V=WXaxH
`
`in which a and b are the experimental measurements in
`mm of length and width. respectively. Each tumor volume
`was expressed subsequently as relative tumor volume
`(RV),
`
`RV = Vn/Vo
`
`in which Vn is the tumor volume at day n and V0 is the
`initial tumor volume when the treatment was started
`(day 0).
`
`Chemotherapy
`
`When the tumor volume reached 100—300 mm’. che-
`motherapy was begun. MMC, CPM. ACNU, ADR, VCR.
`VLB, 5-FU, and MTX were given intravenously at their
`RD or MTD which had been determined previously.3
`Graded doses of each drug were injected intravenously
`into nude mice and their plasma were collected at several
`timepoints. The plasma levels of each drug were assayed
`according to the following methods: M MC and S-FU. by
`microbiologic assay: ADR. ACNU. and VLB. by high-
`pressure liquid chromatography; VCR. as total radioac-
`tivity; MTX. by dihydrofolate reductase inhibition assay;
`and CPM. by fluorometry of metabolically produced ac—
`rolein. Plasma clearance curves obtained from mice were
`
`compared with those of human patients who were given
`a clinical therapeutic dose of the respective drug. taken
`from the literature. The dose that reproduced clinical
`plasma levels most precisely in nude mice was defined as
`the clinically equivalent dose (RD). The MTD of all of
`these drugs were determined to be maximal nonlethal-
`doses by intravenous injection of several doses that were
`increased at a constant ratio of 1.2.
`
`S-FU and MTX were given daily for 5 consecutive days
`
`

`

`No. 8
`
`USEFULNESS OF A HUMAN TUMOR/NUDE MOUSE MODEL
`
`-
`
`Inaba el al.
`
`1579
`
`
`
`
`
`Relativegrowthrate(%ofcontrol)
`
`10
`
`20
`
` 0
`
`0
`
`10
`
`20
`
`FIGS. M AND lB. Responsiveness to maximum tolerated dose and rational dose of mitomycin C of a panel of human breast tumor xenografls.
`The MMC was intravenously injected at its (A) MTD or (B) RD when the tumor size had reached 100 to 300 mm’. Tumor sizes were measured
`with calipers twice a week. and relative growth rates were obtained according to the procedure described in “Materials and Methods." Tumor lines
`are indicated by numbers as follows: i, MX-l: 2. H-31: 3, M02; 4, M05: 5, MC-8; 6, MC-9: 7, Br-lo; 8, MMKY.
`
`Days after treatment
`
`and all other drugs were administered once. Observation
`was continued for 3 to 4 weeks.
`
`Evaluation
`
`On any given experimental day. T/C (9B) was expressed
`as the average of RV of the treated mice with respect to
`the control. The efficacy of each drug was evaluated in
`terms of the T/C (‘5) value on day 14. Evaluation as “ef-
`fective” was based on a T/C (%) of 50% or less, with sta-
`tistical significance determined by the Mann-Whitney U-
`test (P < 0.01. one-sided).
`
`Results
`
`Six of the eight breast tumor lines examined (Table l)
`were medullary tubular adenocarcinoma, and the other
`two lines were papillotubular and common ductal ade-
`nocarcinoma. Growth rates of these tumors in nude mice
`
`were diverse. Growth of MX-l was the most rapid, dou—
`bling in mass in 3.7 days. Growth rates of 1+3] and Br-
`10 were relatively fast. in contrast, MMKY showed ex-
`
`tremely slow growth, doubling in mass in 13.3 days. The
`other four medullary tubular adenocarcinomas were slow
`in growth, and required 8 to 12 days to double in mass.
`With respect to hormone receptors, only Br-IO was estro-
`gen receptor-positive. None of the patients from whom
`the tumors were obtained originally had received che-
`motherapy before tumor excision.
`We studied the responses of these eight breast tumors
`to various antitumor agents. Their responses to MMC.
`for example, appeared as the changes in relative growth
`rate after the treatment (Fig. 1). Therapeutic doses used
`of MMC were MTD (6.7 mg/kg) and RD (1.7 mg/kg),
`which had been determined previously.L3 The MTD of
`MMC was highly effective against all these tumors. Rel-
`ative tumor growth rates on day 14 ranged from 0.1% to
`28% of the control: and complete regression was seen in
`six of six mice bearing MX-l tumor and two of six bearing
`H-3l tumor. in contrast, when the RD of MMC was given,
`only 2 lines, MX-l and MC-8, showed significant re-
`sponses. The efiicacy of RD of MMC against H-31 was
`not as marked, but it was positive according to our criteria
`of evaluation.
`
`

`

`1580
`
`CANCER October 15 1989
`
`Vol. 64
`
`———————__—_—__—_—____
`TABLE 2. Response of Human Breast Tumors Implanted in Nude Mice to Maximum Tolerated Doses of Antitumor Agents
`
`Relative tumor growth rate (T[C $)’
`D ———________________—_
`(mg/kg)
`MX-l
`MC-2
`MC-S
`MC-8
`MC-9
`MMKY
`H-31
`Br-IO
`Drug
`———_—_____—_—__——_
`
`I6?
`87
`8t
`I 7?
`141'
`28'
`291
`0.”
`6.7
`MMC
`77
`35?
`78
`88
`24?
`53
`387
`It
`260
`CPM
`9|
`441’
`62
`75
`25?
`72
`I61
`50'
`48
`ACNU
`57
`321’
`82
`481‘
`3”
`62
`7!
`56
`12
`ADR
`371'
`60
`57
`311
`441'
`75
`98
`0.31’
`1.6
`VCR
`29f
`32?
`[41'
`It?
`2 I f
`161'
`21'
`It
`II
`VLB
`5-H]
`19
`451’
`65
`9|
`47f
`92
`86
`221
`Si
`
`
` MTX 15 IO!) 44? 441’ 84 8| ND 64 ND
`
`
`
`
`
`
`
`
`
`ND: not determined; VCR: vineristine: ADR: Adriamycin (doxoru-
`bicin); VLB: vinblastine; S-FU: S-fluorouncil: CPM: cyclophosphamide;
`MTX: methotreute; MMC: mitomycin C: ACNU: nimustine.
`‘ Determined as ratio (‘5) of mean relative tumor volume ofthe treated
`group to that of the untreated one at d 14 (see “Materials and Methods"
`
`for details).
`1 Values are “effective” according to our evaluation criterim T/C value
`orsos orleswith a statistial significance by the Mann-Whitney U test
`(P < 0.01 . one-sided).
`
`The overall results with MTD of antitumor agents are
`presented in Table 2. MMC and VLB were effective
`against all these tumor lines. In MX- l-bearing and MC-
`2-bean'ng mice treated with VLB, complete regression was
`seen in five and four of six mice, respectively. CPM,
`ACNU, and VCR were significantly effective against four
`of the eight tumors, whereas ADR, S-FU, and MTX were
`effective against two or three tumors. For comparison,
`the overall results with RD of various agents are shown
`in Table 3. Therapeutic efiicacies by RD were inferior
`to those by MTD. RD of MMC and VLB were signifi»
`cantly efl‘ective against three of the eight tumor lines, and
`were equal to the results with ADR. No tumor responded
`to the RD of ACNU. although half of the tumor lines
`responded significantly to its MTD.
`Experimental response rates for all these drugs studied
`are compared with clinical response rates of breast tumors
`
`from the literature (Table 4).“ Since RD ofS-FU and MTX
`seem higher than the respective MTD, response rates for
`RD of both drugs are considered equal to or higher than
`those for their MTD. in general, breast tumors are known
`to be fairly responsive to chemotherapy. Table 4 shows
`that the clinical response rate for the antitumor agents
`examined was 20% or higher, and for CPM, ADR, and
`MTX it was over 30%. No data were available for the
`clinical effect of ACNU on breast tumor. When experi-
`mental response rates for MTD of these drugs were com-
`pared with the clinical data, there was no agreement be-
`tween the rates; experimentally. MMC and VLB showed
`outstanding therapeutic potency that was disproportionate
`to the clinical results. However, when RD of MMC and
`VLB were used, their response rates were not significantly
`high. Therefore, response rates for RD of these drugs
`agreed with the clinical rates.
`
`TABI£ 3. Response of Human Breast Tumors Implanted in Nude Mice to Rational Doses of Antitumor Agents
`
`Relative tumor growth rate (WC '5)’
`Dose
`
`(Ins/ks)
`
`
`
`
`
`
`
` Drug MX-l MC-2 MC-S MC-s MC-9 MMKY ".31 mo
`
`
`
`
`
`
`
`
`
`MMC
`cm
`ACNU
`ADR
`VCR
`vu;
`
`1.7
`65
`s+2+o.s§
`12
`0.4
`2.6
`
`151'
`25+
`33
`56
`52
`4+
`
`81
`59
`as
`7|
`—
`57
`
`68
`4
`—
`62
`—
`79
`
`22?
`49+
`81
`31+
`s4
`as
`
`58
`—
`——
`48+
`74
`35+
`
`83
`—
`—
`82
`—
`70
`
`441
`69
`102
`m
`—
`90
`
`60
`—
`—
`57
`4st
`431
`
`MMC: mitomycin C; CPM: cyclophosplumide'. ACNU: nimustine;
`ADR: Addamycin (doxorubicin): VCR: vincristine: VLB: vinblastine.
`° Determined as ratio (‘5) ofmean relative tumor volume ofthe treated
`group to that of the untreated one at d 14 (see "Materials and Methods”
`for details).
`1' Values are "efl'ective" according to our evaluation criteria: TIC value
`
`ofSOS or les with a statistic] signifimnoe by the Mann-Whitney U test
`( P < 0.01, one-aided).
`1: Judged “incfl'ective” from data on responses to MTD (Table 2).
`§Given as three intermittent injections of 8 mm (0 min). 2 mg/kg
`(25 min), and 0.8 mg/ltg (70 min) in l d.
`
`

`

`No. 8
`
`USEFULNESS or A HUMAN TUMOR/NUDE MOUSE MODEL
`
`-
`
`Inaba el al.
`
`1581
`
`Discussion
`
`Eight human breast tumor lines displayed various drug
`sensitivities as shewn in Table 2. Such divergent intrinsic
`drug sensitivities were seen in other studies that used hu-
`man breast tumor xenogral'ts."7 If we attempt to evaluate
`therapeutic efficacy ofsome new drug against breast tumor
`by using only one breast tumor line. the results of eval-
`uation may differ depending on the tumor line we select
`as a screening tool. If we choose the MX-l line, one of
`the drug-sensitive lines, many compounds may be re-
`garded as effective against breast tumor. In contrast. if we
`use the MMKY line, one of the drug-resistant lines, it
`may be difficult to find compounds active against breast
`tumor. This indicates that it is important to evaluate an-
`titumor activity by using as many tumor lines as possible.
`MMKY. MC-S. and Br-IO were relatively drug insen-
`sitive among these eight tumor lines. However, both M MC
`and VLB showed a significant growth-inhibitory activity
`against these three tumor lines, and thus were effective
`against all eight tumor lines at their MTD. Despite their
`outstanding therapeutic potency against breast tumors in
`this study. there has been no clinical report to support it.
`We assume that this discrepancy in clinical results is due
`mainly to the therapeutic dose given to nude mice. It is
`possible that serious consideration has not given to this
`aspect currently.
`[n a human tumor/nude mouse model we can treat
`human tumors in vivo. However, those tumors are growing
`in nude mice, not in humans. Therefore, the MTD as the
`most effective therapeutic dose is determined by the sen-
`sitivity of nude mice to a drug and by that drug‘s phar-
`macokinetics in the nude mouse. If as many human tu-
`mors as possible are used as a target, treatment with var-
`ious antitumor agents at their MTD for nude mice would
`be substantially different from clinical chemotherapy. To
`reproduce or predict clinical effects in this nude mouse
`model, therapeutic doses used must be standardized in
`terms of human sensitivity to each drug and pharmaco-
`kinetics. Our concept of the RD, the experimental dose
`pharmacokinetically equivalent to the clinical dose, on'g-
`inated from this consideration.3
`ln treatments with the RD. MMC and VLB were sig-
`nificantly effective against three of the eight tumor lines;
`these results are comparable with those of ADR, S-FU.
`CPM. and MTX (Table 3). In comparison with the re-
`sponses to the MTD, the results with the RD seem to
`agree with clinical data in terms of relative efficacy among
`these drugs. The RD of‘ACNU was completely ineffective,
`and we were unable to obtain clinical reports concerning
`ACNU. In relation to this, clinical response rates of breast
`tumors to BCNU and CCNU were reported as 21% and
`
`TABLE 4. Experimental and Clinical Response Rates of Breast
`Tumors to Various Antitumor Agents
`
`Experimental response
`rate (5)
`
`Clinical responsc‘
`
`Antitumor drug
`MTD
`RD
`rate (‘10
`
`20
`38 (3/8)
`100 (8/8)
`MMC
`34
`25 (2/3)
`50 (4/8)
`CPM
`—
`0 (0/8)
`50 (4/8)
`ACNU
`37
`38 (3/8)
`38 (3/8)
`ADR
`2|
`13 (US)
`50 (4/8)
`VCR
`20
`38 (3/8)
`100 (8/8)
`VLB
`26
`238 (3/8)
`38 (3/8)
`S-FU
`
`
`
`233 (2/6)33 (2/6)MTX 34
`
`MMC: mitomycin C; CPM: cyclophosphamide: ACNU: nimustinc;
`ADR: Adriamycin (doxorubicin): VCR: vincristine; VLB: vinblastinc;
`5-FU: S-fluorouracil; MTX: methotrexate; MTD: maximum tolerated
`dose; RD: rational dose.
`
`12%. respectively.‘ These data might suggest that nitro-
`sourea analogs are not as active against breast tumors.
`Two problems need to be solved regarding the RD.
`Firstly, the difficulty in determining precise values of the
`RD. We defined RD as a dose that can reproduce in the
`nude mice the plasma levels of a drug obtained with hu-
`man patients, given its effective dose. Difficulty is ascribed
`to different plasma clearance patterns of most drugs be—
`tween humans and nude mice. Thus, in the case of ACNU,
`three intermittent dosages had to be chosen as the RD.
`Recently, however, we found that the cell killing action
`of cell cycle phase-nonspecific antitumor drugs is depen-
`dent on the concentration-time product or area under
`concentration-time curve (AUC).‘ Therefore. in regard to
`this class of antitumor agents, we may be able to determine
`more accurate RD values.
`
`Another problem is our inability to determine the RD
`at the preclinical stage of new drug development. We can
`determine the RD of a new drug at the end of phase I
`clinical trial. Therefore, the following procedure for new
`drug development is practically available. For example.
`therapeutic effectiveness of a drug against various kinds
`of human tumor is tested at its MTD. V2 MTD, and V.
`MTD. If valuable results are obtained, it will enter phase
`1 clinical trial after preclinical toxicology testing. At the
`end ofthis trial, we can determine the RD, and will know
`that the RD may approximate MTD, V2 MTD, or IA MTD.
`If the RD corresponds to V2 MTD, by the reevaluation of
`its therapeutic efficacy tested previously at '/1 MTD, we
`can predict what types of tumors will be responsive to it.
`We may also predict that no clinical tumor will respond
`to it regardless of its potent activity seen with the nude
`mouse model by use of MTD. This reevaluation will pro-
`vide helpful information for the subsequent phase II trial.
`
`

`

`1582
`
`CANCER October 15 1989
`
`Vol. 64
`
`There have been significant advances in pharmacoki-
`netic studies recently. Human pharmacokinetic param-
`eters, such as distribution volume and total body clear-
`ance, can be predicted by an extrapolation of animal
`data."'° Human MTD of some drugs can be predicted by
`an animal scale-up procedure." Therefore. we may soon
`be able to predict the RD of any new drug at the preclinical
`stage. We are currently interested in fundamental study
`for the prediction of the RD.
`
`REFERENCES
`
`lnaba M, Tashiro T, Kobayashi T et al. Evaluation of response
`l.
`rates to various antitumor agents of human gastric tumors implanted in
`nude mouse. Jpn J Cancer Res (Gann) I986; 77:190—196.
`2. lnaba M. Tashiro T, Kobayashi T er al. Responsiveness of human
`gastric tumors implanted in nude mice to clinically equivalent doses of
`various antitumor agents. Jpn J Cancer Res (Gann) 1988; 79:5 l7—522.
`3.
`lnaba M. Kobayashi T, Tashiro T et al. Phannaeokinetic approach
`
`to rational therapeutic doses for human tumor-bearing nude mice. Jpn
`J Cancer Res (Gann) I988: 79:509—516.
`4. Haskell CM. Giuliano Ali. Thompson RW, Zarem HA. Breast
`Cancer. In: Haskell CM. ed. Cancer Treatment. Philadelphia: WB Saun-
`ders Co., 1985: I37—l80.
`5. Giovanella BC. Stehlin JS, Shepard RC. Experimental chemo-
`therapy of human breast carcinomas heterotransplanted in nude mice.
`In: Proceedings of the Second International Workshop on Nude Mice.
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