Clinical and Endocrineeffectsof the Oral Aromataseinhibitor Vorozolein

Home , Aminoglutethimide

[CAN@@RRESEARcH54, 5875-5881, November 15, 1994) Clinical and Endocrine Effects of the Oral AromataseInhibitor Vorozolein Postmenopausal Patients with Advanced Breast Cancer StephenR.D. Johnston,Ian E. Smith,DebOrahDoody,StephenJacobs,HazelRobertshaw,andMitchell Dowsett' Breast Unit (S. R. D. I., I. E. S.. H. R.J and Academic Department of Biochemistry (S. R. D. J., D. D.. S. J.. M. D.j, Royal Marsden Hospital, FUIhWn Roo4 London@ 5W3 61J England

ABSTRACT hydrochloride is a nonsteroidal competitive inhibitor which, although it is well tolerated and clinically effective (13), at doses required for Vorozole Is an orally active, nonsteroldal aromatase Inhibitor. Twenty estrogen suppression also inhibits the production of aldosterone (14). four poitnienopausal patients with advanced breast cancer who had re lapsedaftertreatmentwithtamoxifenreceivedthreeseparatedailydoses There is still a need, therefore, to develop potent, selective, and well-tolerated aromatase inhibitors for the endocrine treatment of of vorozole (1, 2.5, and 5 mgj each for 1 month In a randomized, double @ blind, II study. There was slgnlflcant suppression (P < 0.001)of postmenopausal women with breast cancer. serum ostradlol at all three doses (median reduction, 91, 90, and 89%, Vorozole2 is a nonsteroidal oral aromatase inhibitor which has been respectively). There was a significant trend (P 0.02) for estradlol to be shown to be 1000-fold more potent than aminoglutethimide in animal suppressed below the detection limit of the assay (3 pmol/liter) more and human studies (15). Previous studies with the vorozole racemate frequently with an Increasing dose of vorozole; 13, 31, and 40%, respec (R76713) have shown that nearly all the aromatase activity resides in thely. Estrosie and estrone-sulfate levels were likewise reduced at each the dextroenantiomer (R83842) (16, 17). In vitro and in vivo animal dose by 52-55% and 64-69%, respectively. There was no significant studies have shown high potency and specificity (18). In a phase I effect at any dose on aldosterone, testosterone, androstenedione, 17ev clinical study of vorozole racemate in postmenopausal women with hydroxyprogesterone, or thyroid-Stimulating hormone levels. A small re advanced breast cancer, doses of 25â€”5mg were well tolerated and duction In cordsol was seen at the 5 mg dose, although the relevance Is unclear given that 17ev-hydroxyprogesterone levels did not aim. Eight resulted in suppression of estradiol <10 pmol/liter (19). Objective patients (33%) achIeved an objective response (2 complete remission, 6 responses in tumor size and subjective responses in performance and perti.1 rendion) with a median response duration of 13 months. Four pain status were observed after 3 months. In a recent study of 12 patients (17%) achIeved disease stabilization for more than 6 months. healthy postmenopausal women, a single p.o. dose of 1, 2.5, or 5 mg Patients who had responded previously to tamoxifen were more likely to vorozole racemate resulted in 93â€”94%inhibition of the in vivo con resp@ to vorozole. There were no significant clinical side effects and the version of androstenedione to estrone (20). In two recent reports from drug w well toIerated@These data suggest that vorozole Is a potent and phase II studies with 2.5 mg vorozole (R83842), objective response selecthe oral aromatase Inhibitor for use In postmenopausal breast rates of 30 and 11% were observed in postmenopausal women with canear. advanced breast cancer, with disease stabilization in an additional 26 and 52% of patients, respectively (21, 22). INTRODUCTION The purpose of this study was to investigate the clinical and endocrine effects of vorozole in postmenopausal patients with Estrogens are thought to promote the growth of breast carcinoma in advanced breast cancer who had progressed when treated with postmenopausal women (1). Effective strategies in the endocrine tamoxifen and to assess tolerabilityand safety. treatment of breast cancer include either antagonizing the interaction ofestrogen with its receptor by using competitive antioestrogens, such MATERIALS AND METHODS as tamoxifen, or by reducing the supply of estrogens by inhibiting aromatase, the enzyme which catalyzes the conversion of androgens Patient Selection. Twenty-four postmenopausal patients with histologi to estrogens. cally or cytologically proven locally advanced or metastatic breast cancer who In postmenopausal women the major source of circulating estro had progressedwhen treatedwith tamoxifen were entered into the study between January 1992 and March 1993. All patients attended the Breast Unit gens is the peripheral aromatization of androgens, in particular an at The Royal Marsden Hospital and had a performance status of less than 2 drostenedione, by the cytochrome P450-regulated enzyme aromatase. according to WHO criteria (23). Postmenopausal status was defined as either Aminoglutethimide was the first aromatase inhibitor to be used in (a) 5 years or more since a spontaneous menopause or (b) follicle-stimulating postmenopausal women with advanced breast cancer. It reduced cir hormone and luteinizing hormone levels >20 lU/liter if <5 years since spon culating levels of estrogen (2), and it was shown to be clinically as taneous menopause. effective as surgical adrenalectomy (3) or tamoxifen (4). However, Patients were ineligible if they had concurrent malignant disease or if they aminoglutethimide also inhibits mineralocorticoid and glucocorticoid were taking concomitant anticancer treatments or steroids. Significant renal or synthesis, and it is often poorly tolerated due to side effects including hepatic dysfunction (creatinine >1.5 X the upper limit of normal; biirubin lethargy, drowsiness, and skin rash (5). >1.5 x the upper limit ofnormal)excluded entry into the study. Patients whose More specific aromatase inhibitors, such as 4-hydroxyandrostenedi primary tumor was known to be ER negative were ineligible. For the assess mentof response,all patientshadat least one measurabletumorlesion, either one (6â€”8)andfadrozole hydrochloride(9â€”11)havebeen developed primary or secondary. and shown to be clinically effective in the treatment of metastatic All previous systemic anticancer therapy was stopped at least 4 weeks prior breast cancerS 4-Hydroxyandrostenedione is a steroidal inhibitor to entry into the study. All patientsgave writteninformedconsent, and the which provides effective aromatase inhibition, although it requires study was approved by the Royal Marsden Hospital Ethical Committee. administration i.m. once every 2 weeks because of first-pass hepatic Study Design. Vorozole was synthesized and obtained from the Clinical metabolism and relatively poor p.o. bioavailability (12). Fadrozole Trials Supplies Production Unit of the Janssen Research Foundation (Beerse,

Received 8/1/94; accepted 9/19/94. 2 The abbreviations used are: vorozole (dextroenantiomer R83842), 6[(4- The osets ofpublication of this article were defrayed in part by the payment of page ch1orophenyl@1Ii-1,2,4-triazol-1-yl)methyl)-1-methyl-1H-benzotriazole; ER, estrogen re chargea@Thisarticle must therefore be hereby marked advertisement in accordance with ceptor, CEA, carcinoembryonic antigen; CV, coefficient of variation; TSH, thyroid 18U.S.C.Section1734solelyto indicatethisfact. stimulating hormone; PR, partial response; NC, no change; CR, complete response; 1 To whom requests for reprints should be addressed. SHBG, sex hormone-binding globulin. 5875

Belgium) and supplied in 1-, 2.5-, and 5-mg tablets to be taken p.o. once daily. and 67%, and the results were corrected for loss. The sensitivity of the assay At entry into the 3-month phase of the study, patients were randomized to one was 25 pmol/liter with intraassay and interassay CV of 8.7 and 10.7%, of three treatment sequences in a double-blind fashion; all patients received the respectively. three doses of vorozole for 1 month at each dose. By giving the three doses of Tumor Markers. Serum CEA was measuredby enzyme immunoassay vorozole in a randomized order, any confounding effect on endocrine response (Roche). Serum marker CA15.3 was measured by enzyme immunoassay by having the lowest dose given first to all patients was eliminated. Similarly (Boehringer-Mannheim). For each parameter all samples on the same patient the randomization was designed to avoid the confounding variables of both were analyzed in the same assay batch. time and sequence order on estrogen suppression. Vorozole Levels. Trough vorozole plasma levels (24 h since previous On entry into the study a full clinical examination was made. Performance dose) were measured by gas chromatography at the end of each 4-week status was assessed according to the WHO scale (23), and pain was assessed treatment phase (Dr. R. Woestenborghs, Janssen Research Foundation). The according to the European Organization in Research on Treatment of Cancer sensitivity of the assay was 1.0 ng/ml. scale (24). Baseline investigations included full blood count, urea and electro Statistics. Because vorozole was effective at suppressing estrogen synthe lytes, creatinine, liver function tests, and electrocardiogram. All clinical, he sis, many of the serum samples during treatment had estradiol levels below the matological, and biochemical assessments were repeated at the end of each detection limits of the assay (3 pmol/liter). Therefore, for calculation of the treatment phase (at 4, 8, and 12 weeks), and at 3-monthly intervals during the mean estradiol levels those samples with undetectable levels have been given open phase. nominal values of 2.9 pmol/liter. The frequency of estradiol suppression below At entry and at 2-weekly intervals during the study, 20 ml of blood were the detection limit for each dose of vorozole was compared using Fisher's taken into plain tubes and centrifuged, and the serum was removed and stored exact test. Estrone and estradiol levels were measured at the second and fourth at â€”20Â°Cforsubsequent endocrine analysis. Serum estradiol and estrone were week during each treatment phase. The Wilcoxon matched-pairs signed-rank measured at the second and fourth weeks of each treatment phase as a measure test showed no evidence of time-effect between these two time points, and the of the potency vorozole. Estrone sulfate was measured at the end of each average of these two measures was calculated for each of the three doses in treatment phase. The other endocrine parameters (androstenedione, testoster each patient. For each parameter an overall comparison of the three doses was one, 17a-hydroxyprogesterone, aldosterone, cortisol, sex hormone-binding made using the Friedman test. The Wilcoxon matched-pairs signed-rank test globulin, and thyroid-stimulating hormone) were measured at the end of each was used to compare the values at each dose with those values pretreatment, 4-week treatment phase as a measure of the selectivity of vorozole. Blood (10 and the median percentage of reduction from baseline calculated for each dose. ml) in a plain tube together with 10 ml of blood in lithium-heparin tubes were The percentage of reduction in tumor size was calculated for each patient taken at entry and at the end of each treatment phase, for measurement of and used to determine whether a partial response (>50% reduction) was tumor markers (CEA and C15.3) and pharmacokinetic studies, respectively. obtained during treatment. Indicator tumor lesions which were to be used to assess response were measured at entry into the study. Skin lesions were measured by calipers, breast lesions by calipers or ultrasound, lung lesions by chest radiograph, and RESULTS deep axillary or mediastinal lesions by computed tomography scan. The product of the bidimensional measurements was used to indicate tumor size. Patient Characteristics. Twenty-four patients were entered into Repeat measurements were made by the same investigator at the end of 3 the study. Of these patients, 20 completed the 3-month treatment months when patients had received all 3 doses, and clinical response was phase of each dose of vorozole, while 4 patients were withdrawn from assessed according to established criteria of the Union Internationale Contre le the study during this period because of disease progression. Fifteen Cancer (25). Patients who showed a complete response, partial response, or no patients continued into the open phase at a dose of 5 mg vorozole change were eligible to continue in the open phase at the maximum 5-mg dose, daily. The median age of the 24 patients was 59 years (range, 45â€”80 and assessment of response was repeated at 3-monthly intervals. Treatment years). Ten patients had presented with locally advanced, metastatic was stopped at the time of documented disease progression. breast cancer at diagnosis, and 14 patients had originally presented Any adverse events were recorded during the trial, and the subjective with early breast cancer and subsequently relapsed. There were a total assessment of response by the patient, together with any changes in concom of 35 measurable sites of disease, of which 15 were chest wall or itant medication, were recorded every 2 weeks during the treatment phase. Radiolmmunoassays. Serum levels of estradiol (26) and testosterone (27) breast recurrences, 6 metastatic skin nodules (other than chest wall), were measured according to previously described methodology. Serum estrone 9 lymph nodes, 2 patients with measurable bone lesions, and 2 lung was measured using a previously described assay (28), but with an antiserum and 1 liver metastases. The ER status of the primary tumor was obtained from Endocrine Science, Calabasas Fills, California, in which the positive in 4 cases and unknown in 20 cases, including those patients sensitivity of the assay was 20 pmol/liter. Serum TSH and aldosterone were who presented with locally advanced, metastatic disease and those measured by immunoradiometricassay kits obtained from Serono Diagnostics. patients whose primary surgery had been performed at another hos @ The performance data for these assays were: TSH, sensitivity 0.04 IU/ml, pital where ER assays were not available. All patients had received intraassay CV 3.1%, and interassay CV 3.9%; aldosterone, sensitivity 23 tamoxifen as their only previous endocrine therapy, 9 as primary pmol/liter, intraassay CV 7.7%, and interassay CV 7.9%. 17a-hydroxyproges therapy where a previous response had been documented, and 15 as terone, cortisol, and androstenedione were measured by radioimmunoassay kits obtained from Biogenesis. The performance data for these assays were: adjuvant therapy (Table 1). 17a-hydroxyprogesterone, sensitivity 120 pmollliter, intraassay CV 10.8%, Endocrine Results. Data from two patients (patients 2 and 23) interassay CV 6.4%; cortisol, sensitivity 2.8 nmol/liter, intraassay CV 10.4%, were excluded from the endocrine analyses because one of the series interassay CV 9.1%;androstenedione, sensitivity 360 pmol/liter, intraassay CV of estradiol values obtained during the three phases of the study were 8.9%, and interassay CV 10.3%. SHBG was assayed using a kit obtained from considered as clinical outliers (values >3 SD from the mean). The Farmos where the detection limit was 0.5 nmol/liter with intraassay and endocrine data from the remaining 22 patients were analyzed. Com interassay CV of 3.2 and 8.3%, respectively. pliance was confirmed by trough vorozole plasma levels which Estrone sulfate was analyzed after hydrolysis, ether extraction, and column showed mean concentrations for the 1-, 2.5-, and 5-mg doses of 2.9 chromatography. One ml of serum, spiked with approximately 1000 cpm of ng/ml (range, 1.0â€”6.0), 12.0 ng/ml (range, 2.5â€”32.8), and 57.5 ng/ml [6,7-NH]estronesulfate(recoverycontrol),wasextractedwithethertoremove (range, 8.9â€”147.0),respectively. unconjugated estrone and then subjected to overnight hydrolysis with sulfatase. Serum estradiol levels were significantly suppressed (P < 0.001) at The ether extracts were dried and chromatographed on Sephadex LH-20 (dichloromethane:ethyl acetate:methanol, 95:5:1). The fractions containing all three doses of vorozole (mean Â±SEM shown in Fig. 1). The estrone were pooled, evaporated, and reconstituted in assay buffer. Two median reduction was 91, 90 and 89% for 1, 2.5, and 5 mg, respec aliquots of 200 @lwereassayed by the same method as was used for estrone, tively. There was a significant trend (P 0.02) for estradiol to be and 300 @lweretaken to estimate recovery. This was generally between 45 suppressed below the detection limit of the assay more frequently with 5876

Table 1 Breast cancer history ______TumorResponse.Attheendofthe3-monthtreatmentphase,six No of patients patients (25%) had a PR, ten patients (42%) showed NC in tumor

Stage at initial diagnosis of breast cancer measurements, and eight patients (33%) progressed during treatment Early disease 14 as defined by Union Internationale Contre Ic Cancer criteria. Of those Advanced disease 10 who progressed, four patients did not complete the 3-month treatment Previous treatments for early disease (n = 14) 14 period. A total of 15 patients (6 PR and 9 NC) continued into the open Surgery + Adjuvant phase of the trial (one patient with NC following 3 months was treated Radiotherapy 8 with chemotherapy rather than continuing in the open phase). One @ Tamoxifen patient with an initial PR subsequently achieved a CR, and 2 patients Chemotherapy with initial NC subsequently responded during the open phase (1PR Previous treatments for advanced disease (n = 24) Surgery for local recurrence 6 and 1 CR). Thus overall, 8 patients (33%) achieved an objective +Adjuvant response to vorozole (2 CR and 6 PR). Disease stabilization (NC), @ Radiotherapy which lasted for a period of at least 6 months, occurred in a total of Tamoxifen Chemotherapy 2 four patients (17%). The remaining three patients with NC after 3 Primary tamoxifen 9 months relapsed within 3 months of continued treatment in the open Chemotherapy (+adjuvant tamoxifen) @@ Radiotherapy (+adjuvant tamoxifen) phase. The objective responses in indicator tumor lesions occurred in local Median time (mo) from diagnosis (range) Presentation with early disease (n = 14) 64 (15-142) breast recurrences (n = 5), lymph nodes (n = 2), and skin nodules Presentation with advanced disease (n = 10) 24 (6-65) (n 3). Fig. 3 shows a computer tomography scan of a subclavicular lymph node prior to and following 3 months of treatment with vorozole, with a greater than 50% reduction in tumor product size.

Table 2 Number of occurrences ofestradiolofLevel levels below the lower limi ofdetection the assay (<3 pnwl/liter)t Estrone of estradiola Vorozole dose (mg)pmol/literTotal1 <3 pmol/liter 3 5 33 2.5 12 27 39 0 42Total5 17 2538 a

85119a 34

Fisher's exact test, P = 0.021.

an increasing dose of vorozole (Table 2). Estrone and estrone sulfate

levels were likewise significantly reduced (Fig. 1); median reduction Vorozols Dose for estrone was 54, 55, and 52% for 1, 2.5, and 5 mg, respectively; median reduction for estrone sulfate was 69, 64, and 67% for 1, 2.5, and 5 mg, respectively. There was no significant difference in the Estradlol 60 reduction of either of these parameters among the three doses of vorozole. @01 The mean values for the other seven endocrine parameters pretreat ment and after each dose of vorozole are outlined in Table 3. There

was no significant change in 17a-hydroxyprogesterone, androstenedi * one, testosterone, aldosterone, or TSH levels at any of the three II1I1mg2.5mg5mgI* I* vorozole doses. There was a small reduction in cortisol levels at the :@ ______5-mg dose only when compared with baseline (P = 0.02; Wilcoxon matched-pairs signed-rank test). Vorozole Dose SHBG levels were lower on treatment with vorozole compared with baseline, although there was no clear relationship with dose. SHBG levels are elevated by tamoxifen and may fall following cessation (29). Analysis by phase of treatment, irrespective of dose of vorozole, Estrone Sulfate suggested that the observed fall in SHBG was related to time. This was confirmed by analyzing SHBG with time in the seven patients T who had been off tamoxifen for more than 2 months, where no significant change in SHBG was observed, and the 17 patients who E0 stopped tamoxifen less than 2 months before starting vorozole, where * a significant fall in SHBG with time was observed [P < 0.01 (Fig. 2)]. a@ T Tumor Markers. Nineteen of the 24 patients had normal or only marginally elevated tumor marker values at entry into the trial. The 1 mg S mg median CEA value prior to treatment was 4 lU/liter (range, 1â€”183), and the median CA15.3 value was 23 lU/liter (range, 6â€”1140).There vorozole Dose was no change in either tumor marker with regard to dose of vorozole Fig. 1. Serum estradiol, estrone, and estrone sulfate values in 22 postmenopausal patients following 28 days of treatment with either 1, 2.5, or 5 mg vorozole ( P < 0.001, or phase of treatment. Likewise, there was no relationship in change comparedwithbaselineon Wilcoxonmatched-pairsigned-ranktest).Columns,mean; of tumor marker with response to vorozole. bars, SEM. 5877

Table 3 Mean serum concentrations (Â±SEM)ofendocrine parameters (excluding estradiol, estrone, and estrone sulfate) before and after 28 days of treatment with each dose of vorozole All endocrine values are expressed as nmollliter except aldosterone, which is expressed in pmollliter, and TSH, which is expressed as mIU/liter.

mgl7a-Hydroxyprogesterone Baseline1 mg2.5 mg5 Â±0.12 Â±0.18 Â±0.21 Â±0.18 Cortisol 364.42 Â±27.62 357.82 Â±26.38 338.29 Â±34.27 304.14 Â±24.910 Androstenedione 4.45 Â±0.42 4.38 Â±0.44 5.13 Â±0.69 4.30 Â±0.38 Testosterone 0.85 Â±0.10 0.82 Â±0.09 0.94 Â±0.13 0.80 Â±0.12 Aldosterone 386.29 Â±53.41 404.59 Â±65.76 447.62 Â±58.16 365.64 Â±39.50 TSH 2.39 Â±0.35 2.96 Â±0.52 3.07 Â±0.52 2.65 Â±0.42 5.48'@aSHBG1.34 82.42 Â±7.231.50 64.27 Â±4.8801.59 71.05 Â±5.61â€•1.59 59.91 Â± p<0.05,comparedwithbaseline(Wilcoxonmatched-pair signed-rank test).

Fig. 4 shows the percentage reduction in four indicator skin nodules except in one patient whose status worsened in relation to disease present in one patient, with a PR observed in three of the four lesions. progression. No objective responses were observed in metastatic deposits in bone, Tolerability. Vorozole was well tolerated by all patients. The side liver, or lung, although in this series of patients the number of effects, which potentially could have been drug related, are listed in indicator lesions for these sites of metastatic disease were low. Table 5. Three patients experienced endocrine related side effects, Of the eight patients who showed either PR or CR with vorozole, including one patient with an increase in the size of her thyroid. This the duration of response (calculated from the start of treatment) has patient had a history of previous thyrotoxicosis several years ago, but been 6, 6, 8, 12, 14, 14+, 16+, and 22+ months. Of the four patients no change in her TSH or free thyroxine was noted and an ultrasound who showed disease stabilization for more than 6 months, the duration of the thyroid was normal. The most common constitutional effects of response was 8, 9, 11, and 25 + months. were a mild headache in two patients and nausea in another two For the 9 patients who were previously treated with primary ta patients. There were no abnormalities detected in the serial electro moxifen, the response to vorozole was significantly associated with cardiograms, and no significant hematological or biochemical previous response to tamoxifen (P = 0.01; Fisher's exact test); 4 of abnormalities. the 6 patients (67%) who had responded to tamoxifen had an objective response to vorozole (1 CR, 3 PR), and 2 patients showed disease DISCUSSION stabilization (NC) for more than 6 months, while the 3 patients who failed to respond to tamoxifen all progressed on vorozole (Table 4). Previous in vitro studies have demonstrated the potency and selec Of the 15 patients who had received only adjuvant tamoxifen therapy tivity of vorozole as an aromatase inhibitor. In follicle-stimulating where the initial hormone sensitivity was unknown, 4 (27%) re hormone stimulated rat granulosa cells, vorozole inhibited aromatase sponded to vorozole (1 CR, 3 PR) and 2 patients had disease stabili with a 50% inhibitory concentration of 1.4 n@t,compared with 3900 zation for more than 6 months. nM for aminoglutethimide in the same system (18). Using a panel of Pain and Performance Status. Only four patients had pain due to different rat primary cells, which reflect different stages in steroid their advanced breast cancer at the start of the trial. Pain was signif biosynthesis, the specificity of vorozole to inhibit estrogen biosynthe icantly improved in one patient with bone metastases in whom no sis was studied. There was no inhibition of progesterone synthesis, change was observed on bone scan or X-ray. Her analgesic require and testosterone and androstenedione synthesis were affected only at ment was reduced from regular opiates prior to treatment to no concentrations 10,000 greater than that required to inhibit estrogen analgesics (4 and 0 on the European Organization for Research on production. In the in vivo model of pregnant mare serum gonadotro Treatment of Cancer scale, respectively) following 3 months of treat phin-primed female rats, vorozole lowered plasma estrogens in a ment with vorozole, and this subjective response was maintained for dose-dependent manner with a 50% effective dose of 0.003 mgfkg 11 months. In three patients, all of whom failed to respond to voro (18). More than 1000-fold higher drug doses were needed to affect zole, pain worsened during treatment. plasma levels of testicular and adrenal steroids in rats. Prior to the study, 22 patients had a WHO performance status of 0. The antitumoral activity of vorozole has been studied in the estro Overall there was no change in performance status during the trial, gen-dependent dimethylbenzanthracene-induced rat mammary tumor

< 2 months since tamoxifen stopped > 2 months since tamoxifen stopped

100 (n=17) 100 (n=7)

Fig. 2. Reduction in SHBG with duration of time(weeks)onvorozole,irrespectiveofdose. The reductionwas significantonly for patients 0 $0 $0 T (n 17) who had only recently stopped ta E 0 C E moxifen for <2 months (@, P = 0.01; *5, C P = 0.002), whereas for patients (n 7) who C., C., had stopped tamoxifen for a much longer time Nc74\\T 59) 60 (>2 months) there was no significant change. 59) points, mean; bars, SEM. I

0 4 5 I) Weeks Weeks

5878

1-mg dose is sufficient to inhibit the aromatase enzyme almost corn pletely. In a phase I study of postmenopausal women with breast cancer, patients were randomized to receive either 2.5 or 5 mg vorozole racernate, and estradiol levels were observed to fall below the detection limit (10 pmol/liter) of the assay (19). The aim of this study was to investigate the endocrine and clinical effects of vorozole at three different doses in postmenopausal women with advanced breast cancer who had progressed during tamoxifen treatment. The results have shown that vorozole caused significant suppressionof serumestradiolby 89â€”91%frombaseline levels at all three doses. There did not appear to be any significant difference in the degree of estrogen suppression among the three doses which were administered in a randomized fashion to prevent any confounding effect on endocrine response. However, there was a significant trend towardsa higherfrequencyof values below the lower detection limit of the assay, which at 3 pmol/literrepresentsa more sensitive lower limit than assays which have previously been used in association with vorozole treatment; 13, 31, and 41% of estradiol values were below this sensitive lower limit following 1-, 2.5-, and 5-mg doses of vorozole, respectively. These data may indicate that the 2.5- and 5-mg doses are more effective at suppressing estrogen biosynthesis. An 89â€”91%reduction in estradiol levels with vorozole compares with a 45â€”72%reductionobserved with fadrozole hydrochloride (14), a 50â€”70%reduction with 4-hydroxyandrostenedione (26) and a 74% reduction observed with the oral aromatase inhibitor CGS 20267 (32). It is, however, important to be cautious in interpreting these data since pretreatment estradiol levels vary greatly among patients and influ ence the percentagesuppressionachieved. Estroneandestronesulfate levels were also significantly suppressed by vorozole. Using a similar assay for estrone, a 52â€”55%suppression seen with vorozole compares r.@inapatientpriorto(a)andfollowing(b)3monthsof with a 35â€”45%suppression observed with fadrozole hydrochloride - atreatment there is a largeleft supraclavicular node (tumor (14) and 60% suppression observed with 4-hydroxyandrostenedione .@ @L@:@@ize following vorozole(tumorproduct, 468 mm@). (12). This estrone assay is less sensitive than that used in a recent report with the oral aromatase inhibitor CGS 20267 where greater U Lpoetselorsaills suppression of estrone (79%) was observed (32). This can be cx @ L antsvlor E Ltorssrm @ L tamoxifenPreviousTable4 Responsetovorozoleinelation to previous response to vorozoleCR/PRaI@5p9;fl$seato

6/12PDCR/PR4response to tamoxifenObjective NC > 20PD0 03Adjuvant tamoxifen4 29 a Responses according to Union Internationale Contre Ic Cancer criteria (25). PD, progressivedisease.

2 months 3 months 5 months robserved in a patient with four assessable skin nodules following Table5 Adverseeventswhichmayhavebeendrugrelated @ The percentageof baselinetumor volume is shownfor each No.of â€”@-- @d 5 months of therapy. patientsEndocrineHot

Flushes2Increased @ dose of 2.5 mg/kg body weight tumor regression was thyroid1ConstitutionalHeadache2Nausea2Diarrhea1Vomiting1Lethargy1Drysize of @ to that seen following ovariectomy. Tumor regres

@. .@ .@ and the occurrence of new tumors during @ was completely inhibited. @ human volunteers vorozole was well tolerated up to @ and resulted in a marked decrease in serum mouth1Loss 4L Theultimateeffectivenessofthedrug,however, ofappetite1Hypertension1Skin which it can inhibit the peripheral aromatization of the main source of estrogens in postmenopausal rash1Back pain1Abdominal Jof12healthypostmenopausalwomen,asinglep.o. pain1Discomfort ]racemate (1â€”5mg)inhibited the peripheral conver tongue1Itching1of :i@T@i@@t:jtoestrone by 93â€”94% (20). Thus, a single 5879

Downloaded from cancerres.aacrjournals.org on October 2, 2021. © 1994 American Association for Cancer Research. VOROZOLE IN ADVANCED BREAST CANCER plained largely by the difference between the assays, as manifest by relapse may help determine those who would benefit most from the higher baseline estrone values observed in this and previous second-line therapy with vorozole. studies. Previous aromatase inhibitors (aminoglutethimide, 4-hydroxyan The data on the other endocrine parameters in this study have drostenedione, and fadrozole hydrochloride) have failed to deliver confirmed the in vitro observations on the selectivity of vorozole for complete aromatase inhibition and estradiol suppression at a dose that the aromatase enzyme (18). No significant effects on the levels of is without significant clinical or endocrine side effects. Vorozole is a testosterone, androstenedione, 17a-hydroxyprogesterone, TSH, or al new, potent, selective, and well-tolerated oral aromatase inhibitor for dosterone were observed at any of the three doses. The apparent fall use in postmenopausal breast cancer. In this phase II study we have in SHBG levels can be explained by the recent cessation of tamoxifen shown that vorozole results in 89â€”91%suppression of estradiol with therapy. When the SHBG data were analyzed in terms of time since out any significant effects on other endocrine parameters. In patients tamoxifen was stopped, a significant fall could be observed only in with advanced breast cancer the drug was well tolerated with an patients who stopped taking tamoxifen for less than 2 months before objective response rate of 33% and disease stabilization in an addi entry into the trial, irrespective of the dose of vorozole. tional 17%. Its clinical efficacy as second-line endocrine therapy is There was a slight reduction in serum cortisol at the 5-mg dose now the subject of a worldwide phase III trial. only. These data could be interpreted as indicative of an effect on either the 21-hydroxylase or 11f3-hydroxylase enzymes. This is un REFERENCES likely since there was no significant rise in the levels of the precursor 1. Muhlblock,0. Roleof hormonesintheetiology of breastcancer.J. Nail. CancerInst., l7ce-hydroxyprogesterone. Previous studies with aminogluthetimide 48: 1213-1220,1972. have shown that increasing doses cause a significant rise in l7ca 2. Santen, R. J., Santner, S., Davis, B., Veldhuis, 3., Samojlik, E., and Ruby, E. hydroxyprogesterone levels before any significant fall in cortisol Aminoglutethimide inhibits extraglandular oestrogen production in postmenopausal womenwithbreastcarcinoma.J.Gin. Endocrinol.Metab.,47: 1257â€”1265,1978. levels is detected (33). in vitro data with both rat adrenal cells (16) and 3. Santen, R. J., Worgul, T. J., Samojlik, E., Interrante, A., Boucher, A. E., Upton, A., human adrenal cells (34) showed that corticosterone levels were Harvey, H. A., White, D. S., Smart, E., Cox, C., and Wells, S. A. A randomized trial comparing surgical adrenalectomy with aminoglutethimide plus hydrocortisone in unaffected by vorozole at doses up to 10 @LM.Inthe phase I study with women with advanced breast cancer. N. Engl. J. Med., 305: 545â€”551,1981. vorozole racemate (R76713) synacthen tests were performed at both 4. Smith, I. E., Harris, A L, Morgan, M., Ford, H. T., Gazet, J-C., White, H., Parsons, the 2.5- and 5-mg doses (19). In that study no effect on circulating C. A., Villardo,A.,Walsh,0., and McKinna,J.A. Tamoxifenversusaminoglute thimide in advancedbreastcarcinoma:a randomisedcross-overtrial. Br. Med. J., cortisol or aldosterone levels or any signs of orthostatic hypotension 283:1432â€”1434,1981. were observed following 4 weeks of treatment with vorozole race 5. Harris, A. L, Dowsett, M., Jeffcoate, S. L, and Smith, I. E. Aminoglutethimide dose and hormone suppression in advanced breast cancer. Eur. J. Cancer Clin. Oncol., 19: mate. In a recent open phase II study with 2.5 mg vorozole (R83842) 493â€”498,1983. adrenal function as determined by synacthen tests was normal in all 6. Coombes, R. C., Goss, P., Dowsett, M., Gazet, i-C., and Brodie, A. M. H. 4-by droxyandrostenedione in treatment of postmenopausal patients with advanced breast patients studied (21). The relevance, therefore, of the observed small cancer. Lancet, ii: 1237â€”1239,1984. reduction in cortisol at the 5-mg dose of vorozole in this study is 7. Goss, P. E., Powles, T. J., Dowsefl, M., Hutchinson, 0., Brodie, A. M. H., Gazet, i-C, unclear and of doubtful clinical significance. and Coombes, R. C. Treatment of advanced postmenopausal breast cancer with an aromatase inhibitor, 4-hydroxyandrostenedione: phase II report. Cancer Res., 46: An objective clinical response of 33% with vorozole is similar to 4823â€”4826, 1986. that observed with aminoglutethimide (4), 4-hydroxyandrostenedione 8. Stein, R. C., Dowsett, M., Hedley, A., Gazet, i-C., Ford, H. T., and Coombes, R. C. The clinical and endocrineeffects of 4-hydroxyandrostenedionealoneand in com (7), and CGS 20267 (32). In addition an additional 17% of patients bination with goserelin in premenopausal women with advanced breast cancer. Br. J. achieved stabilization of their disease for more than 6 months, a Cancer, 62: 679â€”683,1990. response which has been shown to be equivalent to CR/PR in terms of 9. Schieweck, K., Bhatnager,A. S., and Matter,A. CGS 16949A, a new nonsteroidal aromatase inhibitor: effects on hormone-dependent and -independent tumors in s'ivo. progression-free interval (35). As has been observed with other aro Cancer Rca., 48: 834-838, 1988. matase inhibitors, the best responses were seen in local recurrences or 10. Stein,R. C., Dowsett,M.,Davenport,J.,Hedley,A.,Ford,H. T., Gazet,i-C., and Coombes, R. C. Preliminary study of the treatment of advanced breast cancer in soft tissue lesions, rather than in systemic metastases. The biological postmenopausal women with the aromatase inhibitor CGS 16949A. Cancer Res., 50: basis for this difference in response between tissues is unclear. Most 1381-1384, 1990. patients had a normal performance status at entry into the trial and 11. Lipton, A., Harvey, H. A., Demers, L M., Hanagan, i. R., Mulagha, M. T., Kochak, G. M., Fitzsimons, S., Sanders, S. I., and Santen, R. i. A phase I trial ofCOS 16949A: subjective response to vorozole could not therefore be observed for a new aromatase inhibitor. Cancer (Phila.), 65: 1279â€”1285,1990. this parameter. Improvement in pain status, however, was a useful 12. DowseR, M., Cunningham, D., Powles, T. i., Hutchinson, 0., Brodie, A. M. H., Ford, H.T., Gazet,i-C.,andCoombes,R.C. Dose-relatedendocrineeffectsandpharma indicator of response in at least one patient with bone metastases. cokinetics of oral and intramuscular 4-hydroxyandostenedione in postinenopausal Tumor markers were not helpful in these patients as biochemical breastcancerpatients.CancerRes., 49: 1306â€”1312,1989. markers of response. In these patients with advanced breast cancer, 13. Ruts, I. I., Falkson, 0., and Falkson, H. C. A study of fadrozole, a new aromatase inhibitor, in postmenopausal women with advanced breast cancer. J. Clin. Oncol, 10: vorozole was well tolerated with no major clinical, hematological, or 111â€”116,1992. biochemical side effects. This is in contrast to the known systemic 14. Dowsett, M., Stein, R. C., Mehta, A., and Coombes, R. C. Potency and selectivity of thenon-steroidalaromataseinhibitorCGS16949Ainpostmenopausalbreastcancer side effects of aminoglutethimide (5) and local reactions with patients. Chin. Endocrinol., 32: 623-634, 1990. 4-hydroxyandrostenedione (36). 15. Wouters, W., DeCoster, R., Krekels, M., van Dun, i., Beerens, D., Haelterman, C., Although data on primary response to tamoxifen were available in Raeymakers, A., Freyne, E., van Odder, i., Venet, M., and ianssen, P. A. i. R76713, a newnon-steroidalaromataseinhibitor.i. SteroidBiochem.,32:781â€”788,1989. only nine patients because the others had received adjuvant therapy, 16. Wouters,W., DeCoster,R., van Dun, i., KrekeLs,M.D. W. G., Dillen, A., Racy response to vorozole in these patients was significantly associated makers, F., Freyne, E., van Odder, 1., Sanz, 0., Venet, M., and Janssen, M. with a previous response to tamoxifen. In this study the ER status of Comparative effects of the aromatase inhibitor R76713 and its enantiomers on steroid biosynthesis in rat cells in vitro and in vivo. i. Steroid Biochem. MoL Biol., 36: the original primary tumor was available in only four cases. It has 1049â€”1054, 1990. been debated whether the original ER status is of use in selecting 17. Krekels, M. D. W. G., Wouters, W., Van Ginckel, R., ianssens, B., Callens, M., and Dc Coster, R. Aromatase inhibition by R83842, the dextro-isomer of R76713, in patients for additional endocrine therapy when they relapse with 1EG-3 choriocarcinoma grown in ovariectomized nude mice. i. Steroid Biochem. metastatic disease, although recent data suggest that ER-positive Mol.Biol.,41: 761â€”764,1992. tumors which have previously responded to tamoxifen often remain 18. Wouters,W., van Ginckel, R., Krekels,M., Bowden, C., andDeCoster,R. Pharma cology of Vorozole. i. Steroid Biochem. MoI. Biol., 44: 617-621, 1993. ER-positive at relapse (37). Selection of patients at progression on 19. Borms,M., Vandebroek,J.,Rutten,J.,Tytgat,i., DeCoster,R., Langenaeken,C.,and tamoxifen on the basis of previous endocrine response or ER status at Bruynseels, i. Vorozole-racemate (R76713): a specific non-steroidal aromatase in 5880

hibitor pilot study in advanced post-menopausal breast cancer. Eur. J. Cancer, 29(A) F.,andManard,i.Theeffectsoffadrozolehydrochlorideonaldosteronesecretionin (Suppi. 6) SM, 1993. healthy male subjects. J. Clin. Endocrinol. Metab., 74: 571â€”576,1992. 20. Van der Wall, E, Donker, T. H., DeFrankrijker, E., Nortier, H. W. R., Thijssen, 29. Jordan, V. C., Fritz, N. F., and Tormey, D. C. Long-term adjuvant therapy with J.H.H.,andBlankenstein,M.A.Inhibitionoftheinvivoconversionofandrostenedi tamoxifen: effects on sex hormone binding globulin and antithrombin III. Cancer one to estrone by the aromatase inhibitor vorozole in healthy postmenopausalwomen. Res.,47:4517â€”4519,1987. Cancer Res., 53: 4563â€”4566, 1993. 30. Dc Coster, R., Van Ginckel, R. F., Callens, M. J. L, Goeminne, N. K. 0., and 21. Goes, P. B, Clark,R., Ambus,U., Wiezel, H., Crump,M., Martel,M., Wadden,N., Janssens, B. L E. Antitumoral and endocrine effects of (+)-vorozole in rats bearing Shepherd, F., Waldo, D., Tye, L, and DeCoster, R. Phase II Report of vorozole dimethylbenzanthracene-induced mammary tumors. Cancer Res., 52: 1240-1244, (R83842), a new aromatase inhibitor in postmenopausal women with breast cancer. 1992. [email protected]. Qin. Oncol. Annu. Meet., Vol. 13, A156: 88, 1994. 31. Dc Crater, R., Wouters, W., Bowden, C. R., VandenBossche, J., Bruynseels, i., n. Vinholes,J.,Paridaens,R.,Piccart,M.i., Nooij,M.,Klijn,i.M.G.,Rubens, Tuman,R. W., VanGmckel,R., Snoeck, E., Van Peer,A., andJanssen,P. A. J. New It D., Beex, L V. A., Van Vreckem, A., and Tromiak, E. An EORTC Breast nonsteroidal aromatase inhibitors: focus on R76713. i. Steroid Biochem. Mol. Biol., Group Phase II Study of vorozole (R83842), a new aromatase inhibitor in 37: 335â€”341,1990. advanced breast cancer (ABC). Proc. Am. Soc. Clin. Oncol. Annu. Meet., Vol. 13, 32. Iveson, T. 3., Smith, I. E., Ahern,J., Smithers,D., Trunet,P. E., and Dowsett, M. A223:105, 1994. Phase I study of the oral nonsteroidal aromatase inhibitor CGS 20267 in postmeno 23. Miller, A. B., Hoogstraten, B., Staquet, M., and Winkler, A. Reporting results of pausal patients with advanced breast cancer. Cancer Rca., 53: 266â€”270,1993. cancer treatment. Cancer (Phila.), 47: 207â€”214,1981. 33. Harris, A. L, Dowseft, M., Smith, I. E., and ieffcoate, S. L Endocrine effects of low 24. European Organisation for Research and Treatment of Cancer. Cancer-related pain dose aminoglutethimide alone in advanced postmenopausal breast cancer. Br. J. andanalgesicscore.In: ManualforQinicalResearchinBreastCancer,EORTC Cancer,47:621â€”627,1983. Breast Cancer Co-Operative Group, 1991. 34. Wouters, W., Dc Coster, R., Beerens, D., Doolaege, R., Gruwez, 3.A., Van Camp, IC, 25. Hayward,J. L, Carbone, P. P., Heuson, i-C., Kumoaka, S., Segaloff, A., and Rubens, Vanderpas, H., and Van Herendael, B. Potency and selectivity of the aromatase R. D. Assessmentofresponsetotherapyinadvancedbreastcancer.Eur.J. Cancer, inhibitor R76713; a study in human ovarian, adipose stromal, testicular and adrenal 13: 89â€”94,1977. cells. J. SteroidBiochem. Mol. Biol., 36: 37â€”65,1990. 26. Dowsett, M., Gaas, P. E., Powles, T. i., Hutchinson, G., Brodie, A. M. H., ieffcoate, 35. Howell, A., Mackintosh, I., and iones, M. The definition of the â€˜no-change'category S. L, and Coombes, R. C. Use of the aromatase inhibitor 4-hydroxyandrostenedione in patients treated with endocrine therapy and chemotherapy for advanced carcinoma in postmenopausal breast cancer: optimization of therapeutic dose and route. Cancer of the breast. Eur. i. Cancer am. Oncol., 24: 1567â€”1572,1988. Rca., 47: 1957â€”1961,1987. 36. Coombes, R. C., Hughes, S. W. M., and Dowsett, M. 4-Hydroxyandrostenedione: a 27. Dowsett,M@Mehta,A., Mansi,i., andSmith,I. E. A dose-comparativeendocrine new treatmentforpost-menopausalpatientswith breastcancer.Eur.i. Cancer,284: clinical study ofleuporelin in premenopausal breast cancer patients. Br. i. Cancer, 62: 1941â€”1945,1992. 834â€”837,1990. 37. Johnston, S. R. D., Smith, I. E., King, N., and Dowsett, M. Oestrogen receptor 28. Trunet, P. F., Meuller, P., Girard, F., Aupetit, B., Bhatnager, A. S., Zognbi, F., Ezzet, expression and function in tamoxifen resistant breast cancer. Breast, 2: 193, 1993.

5881

Downloaded from cancerres.aacrjournals.org on October 2, 2021. © 1994 American Association for Cancer Research. Clinical and Endocrine Effects of the Oral Aromatase Inhibitor Vorozole in Postmenopausal Patients with Advanced Breast Cancer

Stephen R. D. Johnston, Ian E. Smith, Deborah Doody, et al.

Cancer Res 1994;54:5875-5881.

Updated version Access the most recent version of this article at: http://cancerres.aacrjournals.org/content/54/22/5875

E-mail alerts Sign up to receive free email-alerts related to this article or journal.

Reprints and To order reprints of this article or to subscribe to the journal, contact the AACR Publications Subscriptions Department at [email protected].

Permissions To request permission to re-use all or part of this article, use this link http://cancerres.aacrjournals.org/content/54/22/5875. Click on "Request Permissions" which will take you to the Copyright Clearance Center's (CCC) Rightslink site.