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Antitumor Effects andAnticancer Applications of Bisphosphonates

Gareth Morgana and Allan Liptonb

Bisphosphonates are firmly entrenched in the treatment of metastatic bone disease secondary toseveral tumor types, including breast cancer, prostate cancer, and myeloma. More recently, anemerging body of preclinical and clinical evidence indicates that bisphosphonates might alsoexhibit antitumor activity. This expanded role for bisphosphonates in the adjuvant setting mighthave profound clinical implications in many cancer types, particularly in the context of preventionof bone metastasis. Increased understanding of the mechanistic basis of the antitumor effectsindicates that these might occur via direct mechanisms such as induction of apoptosis andinhibition of tumor cell adhesion and invasion, as well as indirect mechanisms such as inhibition ofangiogenesis. There is also considerable evidence to suggest that nitrogen-containing bisphospho-nates might exert additive or synergistic interactions with standard cytotoxic agents. However,mature clinical data with bisphosphonates are limited and, thus far, provide conflicting evidenceregarding the antitumor role of bisphosphonates, but have mostly been conducted with first-generation bisphosphonates such as clodronate that are not as effective as next-generation bisphos-phonates. Several large randomized clinical trials are ongoing with the next-generation bisphos-phonate zoledronic acid to prospectively confirm an antitumor role for bisphosphonates in varioustumor types. This review assesses the current body of preclinical and clinical evidence in favor ofan antitumor effect of bisphosphonates in different cancer types.Semin Oncol 37 (Suppl 2):S30-S40. © 2010 Published by Elsevier Inc.

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isphosphonates are potent inhibitors of oste-oclast-mediated bone resorption. The promi-nent role of bisphosphonate therapy in the man-

gement of patients with metastatic skeletal disease isell established. In addition to reducing skeletal mor-idity, it is increasingly being recognized that bisphos-honates might also exert direct or indirect antitumorffects in many cancer types. This review proposes torovide a distillation of the current preclinical andlinical evidence favoring the antitumor effects ofisphosphonates in cancers that metastasize to theone, including breast cancer, prostate cancer, andyeloma.

Royal Marsden Hospital, Sutton, Surrey, United Kingdom.Milton S. Hershey Medical Center, Penn State University, Hershey, PA.ublication of this article was supported by an educational grant fromNovartis Pharmaceuticals Corporation.

ddress correspondence to Gareth Morgan, MD, PhD, Department ofHaemato-oncology, The Royal Marsden Hospital, Downs Road, Sut-ton, Surrey SM2 5PT, UK. E-mail: gareth.morgan@rmh.nhs.uk

270-9295/ - see front matter2010 Published by Elsevier Inc.

aoi:10.1053/j.seminoncol.2010.10.005

Seminars in On30

RECLINICAL EVIDENCE IN SUPPORT OF THENTITUMOR EFFECTS OF BISPHOSPHONATES

reclinical Evidence From In Vitro Studies

Direct Antitumor Effects

The primary antitumor mechanism of bisphospho-ates is proposed to be direct induction of apoptosis insteoclasts and tumor cells.1 Bisphosphonates haveemonstrated direct anti-apoptotic effects in differentancer cell lines, including myeloma, breast cancer,rostate cancer, and lung cancer in vitro in a dose- andime-dependent manner.1 While both nitrogen-contain-ng and non–nitrogen-containing bisphosphonates areffective in inducing apoptosis of tumor cells, nitrogen-ontaining bisphosphonates appear to exhibit higherotency. It is notable that the concentration of bisphos-honates required to induce tumor cell apoptosis isigher (10–100 �mol/L) than those documented for

nduction of osteoclast apoptosis, for tumor cell inva-ion, or adhesion in vitro or the 1-�mol/L peak plasmaoncentrations reported from clinical studies, high-ighting the importance of achieving pharmacokineticevels of bisphosphonates to mediate antitumor ef-ects.2 Senaratne et al demonstrated that zoledronic

cid induced apoptosis in human breast cancer cell

cology, Vol 37, No 5, Suppl 2, October 2010, pp S30-S40

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Antitumor effects and anticancer applications of bisphosphonates S31

ines via mitochondrial release of cytochrome c andriggering the caspase-3 pathway.3 In addition to up-egulation of the proapoptotic regulatory protein bcl-2,nhibition of Ras activation by blockade of enzymesnvolved in protein prenylation may contribute to theffects of zoledronic acid on tumor cell apoptosis.3,4

here is also ample evidence to suggest that nitrogen-ontaining bisphosphonates show additive or synergis-ic anti-apoptotic effects with standard cytotoxic agentsn different experimental models.4

Bisphosphonates are also strongly implicated in thenhibition of tumor cell adhesion and invasion, whichepresent key steps in the metastatic process. Theisphosphonates pamidronate, alendronate, clodronate,

bandronate, and zoledronic acid lead to dose-depen-ent and specific inhibition of breast and prostate car-inoma cell adhesion to mineralized and non-mineral-zed bone matrices, which importantly did not extendo normal cells.5,6 Boissier et al demonstrated thatoledronic acid was the most potent bisphosphonateollowed by ibandronate, active form of risedronate,nd clodronate. Notably, the antitumor effects ofisphosphonates appeared to be concentration-depen-ent as evidenced by experimental data that correlatedoledronic acid–induced effects on tumor cell apopto-is, tumor cell motility, and tumor cell invasion atifferent concentrations.6 It was proposed that, at lowoncentrations in the submicromolar range, bisphos-honates mediated effects on tumor cell invasion via

nhibition of the mevalonate pathway that leads torenylation of small guanosine triphosphatase (GTPase);isphosphonate-mediated inhibition of tumor cell inva-ion was partially reversed by the addition of meval-nate pathway intermediates, geranylgeraniol andrans-trans-farnesol.7 However, at higher concentra-ions, bisphosphonates inhibit matrix metalloprotein-se activity that results in degradation of extracellularatrix (ECM), a critical step for migration and inva-

ion.6 Treatment of breast cancer cells witholedronic acid also inhibited stromal cell–derived fac-or-1 (SDF-1)/CXCR4-mediated chemotaxis and also de-reased CXCR4 cell surface expression.8

Indirect Antitumor Effects

The bidirectional interplay between bone-derivedrowth factors and tumors instigates the self-sustainingicious cycle of development and progression of boneetastasis. Several growth factors found in the boneilieu such as insulin-like growth factor (IGF)-I, IGF-II,

nd fibroblast growth factor (FGF)-2 have been impli-ated in promoting the proliferation of tumor cells initro.9 Treatment with bisphosphonates such as clodr-nate, ibandronate, pamidronate, and zoledronic acidas been shown to completely or partially reverse thetimulatory effects of these growth factors on breast

ancer cell proliferation.9 Clinically relevant doses of t

oledronic acid have also reduced expression of COX-2,onsequently reducing SDF-1/CXCR4-mediated effectsn tumor cell homing to the bone.8

Some preclinical evidence indicates that bisphos-honates are potent inhibitors of angiogenesis, a keyrocess in tumor growth and progression. In experi-ental models, zoledronic acid was able to inhibit

rowth factor–stimulated proliferation of endothelialells in vitro, and demonstrated dose-dependent inhi-ition of angiogenesis in vivo.10,11 Moreover, zoledroniccid specifically inhibited �v�3 integrin–mediated en-othelial cell adhesion but did not affect adhesion me-iated by �5�1 integrin.12 �v�3 integrin is a key media-or of tumor cell invasion, migration, and adhesion toineralized bone and bone matrix proteins in addition

o being a regulator of proangiogenic factors.13

Nitrogen-containing bisphosphonates also exhibitmmunomodulatory properties, particularly with re-ard to regulation of �� T-cell–mediated host immuno-urveillance for tumor cells. In addition to activatinghe cytolytic function of �� T cells, zoledronic acid alsonduced maturation of interferon-�–producing ��

cells and upregulated expression of surface recep-ors such as CD40, CD80, and CD83 on peripheral ��

cells.14,15

reclinical Evidence Fromn Vivo Animal Models of Metastasis

Experimentation in animal models is vital to under-tanding the interactions between tumor cells and theone microenvironment that precedes effective trans-

ation of emerging agents into the clinic. Multiple my-loma, breast cancer, and prostate cancer have beenhe focus of the animal studies using bisphosphonates.n these studies, bisphosphonates have been adminis-ered either in a prevention setting (at the time ofumor inoculation) or in a treatment setting (after boneetastases have been established). A vast body of ac-

umulated preclinical data suggests that the antitumorffects of bisphosphonates in bone lesions are via inhi-ition of bone resorption and decreased tumor burdenoncomitant with induction of tumor cell apoptosisnd inhibition of tumor cell adhesion and invasion.2

Croucher et al, using a multiple myeloma animalodel, demonstrated that administration of zoledronic

cid after osteolytic lesions were established, signifi-antly reduced progression of osteolytic lesions, in-reased bone mineral density, and decreased tumorurden.11 Treatment of tumor-bearing mice witholedronic acid also decreased angiogenesis and in-reased survival. These results were replicated inreast cancer metastatic models, where administrationf zoledronic acid blocked the formation of new osteo-

ytic lesions and inhibited progression of establishedone metastases and tumor expansion.16 Similarly,

reatment with ibandronate inhibited the progression

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S32 G. Morgan and A. Lipton

f established osteolytic lesions and decreased skeletalumor burden compared to controls in breast cancer–erived bone metastasis animal models.17 In an elabo-ate breast cancer mouse model of bone metastasis,isedronate was administered in three different exper-mental protocols: administration after development ofsteolytic metastatic lesions, administration along withumor injection, or prophylactic administration beforeumor injection into mice.18 In all instances, risedr-nate inhibited osteoclast-mediated bone resorption,lowed progression or inhibited development of osteo-ytic metastatic lesions, increased survival, and de-reased tumor burden compared to controls.18,19 Thentitumor activity was bone-specific, as risedronate didot affect the growth of metastatic cancer cells in theoft tissues surrounding bone.18 The authors concludedhat prophylactic administration of bisphosphonates inancers with a predilection for the bone might preventevelopment of bone metastasis that might lead torolongation of survival.

Although still controversial, there is some evidenceo suggest that zoledronic acid can also inhibit visceraletastases.20 In an orthotopic mammary tumor model,

reatment with zoledronic acid after tumor cell inocu-ation resulted in decreased tumor burden in liver andung in addition to reduction in skeletal tumor burden,

hich translated into prolongation of survival in tumor-earing mice compared to controls.20 These effectsere attributed largely to inhibition of tumor cell mi-

ration and invasion. In the same model, clodronatend pamidronate did not have the same effect on vis-eral metastasis and survival as zoledronic acid. More-ver, Daubine et al demonstrated that continuous dailyr weekly zoledronic acid dosing regimens were moreffective at decreasing skeletal burden compared toither a single-dose zoledronic acid or daily clodronateegimen.21 Additionally, frequent zoledronic acid dos-ng was proposed to promote the antitumor activity ofisphosphonates. Similarly, preventative regimens withontinuous dosage of zoledronic acid significantly re-uced the number of tumor cells in the bone marrowompared to either single-dose zoledronic acid or con-rol, implicating a beneficial role for bisphosphonatesn the adjuvant setting. Insights gained from these stud-es indicate that bisphosphonates, particularly the ni-rogen-containing bisphosphonates, have the potentialo reduce tumor burden in bone and prevent develop-ent and progression of bone metastases.

linical Evidence ofntitumor Effects of Bisphosphonates

Breast Cancer

Adjuvant trials with clodronate. Diel et al con-ucted the first trial to evaluate the effect of postoper-tive clodronate therapy in addition to standard surgi-

al therapy on the incidence and extent of new s

etastasis in 302 patients with primary breast cancernd tumor cells in the bone marrow.22 After a medianollow-up of 3 years, distant metastases were signifi-antly lower in patients that received clodronate ther-py for 2 years compared to those in the control group21/157 v 42/145; P �.001). The incidence of bothkeletal (8% v 17%; P � .003) and visceral metastases8% v 19%; P � .003) was lower in the clodronateroup compared to the control group. In this prelimi-ary analysis, clodronate therapy resulted in signifi-antly higher overall survival (OS) compared to controlP � .001).22 These results were sustained in the 55-onth follow-up with a significant decrease in boneetastases and significantly improved disease-free sur-

ival (DFS) and OS compared to the control group.23,24

t the 104-month follow-up, the differences in inci-ence of skeletal metastases and visceral metastasesnd the improvement in DFS were no longer statisticallyignificant, while the improvement in OS was of border-ine significance.23 It is conceivable that a treatment foronger duration might be necessary to maintain the im-rovements initially obtained (Table 1).22,23,25–32

Similar results were reported by Powles et al in aarge randomized placebo-controlled study of 1,069

omen with stage I–III breast cancer.25 In the initialeport, adjuvant clodronate therapy for 2 years resultedn a nonsignificant reduction in incidence of bone me-astases (63 v 80; hazards ratio [HR], 0.77; 95% confi-ence interval [CI], 0.56–1.08; P � .127), while the

ncidence of non-osseous metastasis was similar be-ween the two treatment arms. However, during theedication period of 2 years, the reduction in inci-

ence of bone metastasis was statistically significant12 v 28; HR, 0.44; 95% CI, 0.22–0.86; P � .016). Thenal analysis results showed a significant reduction inhe risk of bone metastases in the clodronate groupompared to placebo over both the 2-year medicationeriod (19 patients v 35 patients; HR � .546, P � .031)nd the 5-year follow-up period (51 patients v 73 pa-ients; HR � 0.692, P � .043).26 Importantly, a signifi-ant reduction in the risk of death was associated withlodronate therapy compared to placebo for patientsith stage II–III disease (HR � 0.592; P � .009).26

esults from the Powles and the Diel studies suggesthat clodronate therapy in an adjuvant setting mightotentially prevent bone metastases, but the protectiveffects might diminish on cessation of treatment, indi-ating that longer treatment schedules may be requiredo maintain the effect of clodronate.2 (Table 1).

In contrast to these results, a smaller study by Saartot al of 299 women with primary node-positive breastancer demonstrated a similar rate of bone metastasisetween clodronate therapy and control at a follow-upt 5 years27 (Table 1). Moreover, clodronate therapyignificantly increased the rate of nonskeletal metasta-es (43% v 25%; P � .0007), and was associated with

ignificantly lower rates of OS (70% v 83%, P � .009)

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Antitumor effects and anticancer applications of bisphosphonates S33

nd DFS (56% v 71%, P � .007) compared to control.27

t the 10-year follow-up, there was still no difference inhe frequency of bone metastases between the treat-ent arms and the frequency of nonskeletal metastasesas significantly higher in the clodronate group. How-

ver, there was no significant difference in the OSetween the two treatment groups.33 Although theseesults suggested that adjuvant clodronate therapy didot prevent the development of bone metastasis, andight even be associated with a negative effect on

urvival, these results must be cautiously interpretedince the patient characteristics were imbalanced be-ween the two arms in terms of increased representa-ion of estrogen-negative patients on the clodronateherapy arm. However, in a meta-analysis of approxi-ately 1,650 patients, adjuvant clodronate therapy didot significantly increase bone metastasis-free survivalHR � 0.68), nonskeletal metastases-free survival (HR �.89), or OS (HR � 0.75) in patients with early breastancer compared to those who did not receive anyctive treatment.34

The ongoing randomized National Surgical Adjuvantreast and Bowel Project (NSABP) B-34 trial is com-

Table 1. Clinical Evidence of Antitumor Role of B

Study

Clodronate therapyDiel et al 22–23 Media

22

MediaSim2

Powles et al25,26 2 in2 in

Saarto et al27 Simila2 OS2 DF

Pamidronate therapyKokufu et al28 2 in

1 inSimila

Jung et al29 2 inSimila

Zoledronic acid therapyZO-FAST30 2 inABCSG-1231 1 in

1 inTrend

AZURE32 2 inAbbreviations: RITS, residual invasive tumor size; OS, overall su

survival.

aring standard adjuvant treatment plus clodronate b

,600 mg daily to standard treatment plus placebo inatients with stage I–III breast cancer. The trial plans toandomize a proposed 3,350 patients to the two treat-ent groups; the primary endpoint of the study isFS35,36 (Table 2).2,35,37–45

Adjuvant trials with pamidronate. Limited clini-al evidence, mostly from relatively small, nonrandom-zed, single-center experiences, of the effect of pamidr-nate therapy in preventing or reducing the incidencef bone metastases exists (Table 3).43–46 An early studyf 124 patients with breast cancer, either locally ad-anced disease or extraskeletal metastases but no boneetastases, evaluated the effect of pamidronate ther-

py on first development of bone metastasis.47 In thistudy, bone metastasis was reported in 36% of patientsho received pamidronate compared to 27% in the

ontrol group. In contrast, a small trial of 90 patientsith breast cancer with four or more positive nodesho were assigned to receive pamidronate or control,

howed a significant reduction in incidence of boneetastases in patients treated with pamidronate com-ared to the control group (12% v 39%; P � .008) while

sphonate Therapy in Breast Cancer

Results

onth follow-up:metastasis (7.6% v 17.2%; P � .003)

hs (3.8% v 15.2%; P � .001)-month follow-up:es of bone metastasis (23.6% v 26.2%; P � .770)hs (20.4% v 40.7%; P � .049)bone metastasis (HR � 0.692; P � .043)death (HR � 0.768; P � .048)of bone metastasisv 83%; P � .009)v 71%; P � .007)

etastasis (12% v 39%; P � .008)etastasis–free survival (85% v 64%, P � .035)

nd DFSetastasis (2.3% v 8.7%; P � .008)

nd DFS

DFS events (HR � 0.59; P � .0314)R � 0.65; P � .01)R � 0.64; P � .01)d 1 in OS (HR 0.60, P � .11)RITS (15.5 mm v 27.4 mm; P � .006)FS, disease-free survival; HR, hazard ratio; RFS, recurrence-free

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S34 G. Morgan and A. Lipton

n the pamidronate treatment group (85% v 64%, P �035) at a median follow-up of 5.4 years.28 However,hese differences did not translate into an improvementn OS and DFS between the two treatment groups.28

imilarly, Jung et al reported that the incidence of boneetastasis was significantly lower in patients who re-

eived pamidronate therapy compared to the controlroup (2.3% v 8.7%) in 429 perimenopausal womenith primary operable stage I–III breast cancer over aeriod of 4 years; there was no difference in OS andFS between the two treatment cohorts.29

Clinical trials with zoledronic acid. Based on ev-dence that the next-generation bisphosphonates show

ore potent bone resorptive activity compared to first-eneration agents, zoledronic acid is being activelynvestigated in several tumor types including breastancer. Early signals of the effect of zoledronic acidn preventing bone metastasis were demonstrated in

Table 2. Ongoing Clinical Trials With Bisphosph

Study Regimen

ProposNo. o

Patien

Breast cancerNSABP B-3435 Clodronate or placebo 3,00AZURE2 Zoledronic acid or

placebo3,36

SWOG 030737 Clodronate,risedronate, orzoledronic acid

5,40

NATAN38 Zoledronic acid orcontrol

65

Prostate cancerZEUS39 Standard treatment v

standard treatmentwith zoledronic acid

1,30

RADAR40 Duration of androgensuppression: 5months v 18months with orwithout zoledronicacid

1,00

CALGB 9020241 Early versus standardzoledronic acid

68

Lung cancerStudy 241942 Zoledronic acid v

control44

Abbreviations: NSCLC, non-small cell lung cancer; PSA, prostate

small randomized pilot study of 40 patients with s

olid tumors but without bone metastases.48 At-year follow-up, zoledronic acid therapy resulted inignificant reduction in bone metastasis compared toontrol (60% v 10%; P �.0005). This difference wasustained in the 18-month follow-up, with 20% ofatients in the zoledronic acid group bone metasta-es-free compared to 5% in the control group (P �0002).48 The phase III Austrian Breast & Colorectalancer Study Group (ABCSG)-12 trial compared en-ocrine therapies goserelin plus tamoxifen or anas-razole, with or without zoledronic acid for 3 years in,800 premenopausal patients with hormone recep-or–positive breast cancer.31 At a median follow-upf 4 years, the combination of endocrine therapy andoledronic acid resulted in significant improvementn recurrence-free survival (HR � 0.65, P � .01) andFS (HR � 0.64, P � .01) compared to no zoledroniccid. Moreover, the addition of zoledronic acid

for Prevention of Bone Metastasis

Target Population Primary Endpoint

age I-III breast cancer Disease-free survivalage II or III breast cancerat high risk of relapse

Disease-free survival

age I-III breast cancer Disease-free survival

age II-III breast cancerwith chemo-insensitivedisease

Event-free survival

igh-risk prostate cancer Prevention of bonemetastases

ostate cancer PSA relapse-freesurvival

ostate cancer metastaticto bone

Prevention of skeletal-related events

ewly diagnosed, stageIIIA and stage IIIBNSCLC with no evidenceof pleural effusions

Prevention of bonemetastasis

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Antitumor effects and anticancer applications of bisphosphonates S35

each statistical significance (HR � 0.6; 95% CI,.32–1.11; P � .10)31 (Table 1).

The ongoing multicenter studies Zometa-Femara Ad-uvant Synergy Trial, Z-FAST and ZO-FAST, are twoimilarly designed trials that are evaluating the efficacynd safety of zoledronic acid in preventing bone lossssociated with adjuvant aromatase inhibitors (AIs) inostmenopausal women with breast cancer.49 In theserials, postmenopausal patients with stage I–IIIa hor-one receptor–positive breast cancer were random-

zed to receive either upfront or delayed zoledroniccid with adjuvant letrozole. Importantly, the 36-monthollow-up results of the ZO-FAST trial in 1,065 patientshowed a significant 41% relative risk reduction for DFSvents (P � .0314) in the upfront zoledronic acidroup compared to delayed therapy30 (Table 1). In the-FAST trial, disease recurrence was similar betweenhe two treatment arms (22 v 26 patients); however,onger follow-up data might be needed to discern anyifferences owing to the small patient numbers, shortollow-up of this analysis, and good prognosis of theseatients.50

The ongoing Adjuvant Zoledronic acid redUce RE-urrence (AZURE) trial is a prospective randomizedhase III trial of 3,360 patients with stage II/III breastancer that will evaluate the effect of zoledronic acidor 5 years on survival and recurrence for a prolongeduration of treatment to receive adjuvant therapy withr without zoledronic acid.2 Recent exploratory evi-ence from a subgroup analysis of the AZURE trialuggests that zoledronic acid in combination with neo-djuvant chemotherapy might confer an antitumor ef-ect in patients with early-stage breast cancer.32 In 205atients on the AZURE trial who received neoadjuvanthemotherapy with or without zoledronic acid, therimary endpoint was pathologically assessed residual

nvasive tumor size (RITS) at surgery, while the second-ry endpoints were pathologic complete response

Table 3. Clinical Evidence of Antitumor Role of B

Study Regimen

McCloskey et al43 Clodronate v placebo

Avila et al44 Zoledronic acid v control

Berenson et al45 Zoledronic acid v pamidronaMorgan et al46 Zoledronic acid v clodronate

Abbreviation: OS, overall survival; EFS, event-free survival; HR, h

pCR) rate and axillary nodal involvement. Addition of T

oledronic acid to chemotherapy significantly reduceddjusted mean RITS compared to chemotherapy alone15.5 mm v 27.4 mm; P � .006). Although the pCR rateas also higher with addition of zoledronic acid com-ared to without, it did not reach statistical significance12% v 7%; P � .146). These encouraging results alsoarrant the evaluation of zoledronic acid in combina-

ion with neoadjuvant chemotherapy in prospectiverials (Table 1).

Several ongoing trials are actively evaluating the rolef adjuvant and neoadjuvant bisphosphonate therapyo prevent bone metastasis. Anticipating that theZURE and NSABP-34 trials will show a benefit ofdjuvant bisphosphonate therapy, the Southwest On-ology Group (SWOG)-S0307 trial was designed to es-ablish the choice of the bisphosphonate to use in thedjuvant trial setting.40 This trial directly compares clo-ronate (1,600 mg/d, oral, for 35 months) versusoledronic acid (4 mg/mo for 6 months, then every 3onths for 2.5 years) versus ibandronate (50 mg/d,

ral, for 35 months) therapy in 4,500 patients withtage I–IIIA breast cancer and no evidence of metasta-is. After completion of therapy, patients will be mon-tored every 6 months until disease progression, andhen annually for up to 10 years. The objectives of therial include comparison of DFS, OS, sites of first dis-ase recurrence, and adverse events. This trial has com-leted accrual and interim analysis results are awaited.he open-label randomized phase III Postoperative Usef Zoledronic Acid in Breast Cancer Patients After Neo-djuvant Chemotherapy (NATAN) trial is comparinghe postoperative use of zoledronic acid for 5 yearsersus no treatment in 654 patients with primary breastancer who have residual tumor after preoperativeaxane-containing chemotherapy. The primary out-ome is to evaluate the effect of zoledronic acid ther-py on event-free survival (EFS); secondary outcomesnclude OS, bone metastases–free survival, and toxicity.38

sphonate Therapy in Multiple Myeloma

Results

All patients: Similar OS (P � .38)Subgroup of patients with no skeletal fractures at

diagnosis:1 in OS (46% v 35%; P � .006)1 in EFS (80 % v 52%; P �.01)1 in OS (80% v 46%; P �.01)1 in OS (76% v 63%; P � .026)2 in SRE (27.0% v 35.3%; P � .0004)2 in risk of death (HR � 0.842; P � .0118)2 in risk of progression (HR � 0.883; P � .0179)tio; SRE, skeletal-related events.

ispho

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S36 G. Morgan and A. Lipton

f Zoledronic Acid to Pre-Operative Chemotherapy inreast Cancer (ANZAC) trial is a randomized phase II

easibility study that explores the potential synergisticntitumor effects of zoledronic acid and anthracyclineytotoxic drugs in a neoadjuvant clinical setting.51 Eli-ible patients with invasive breast cancer undergoingeoadjuvant chemotherapy will either receive an infu-ion of zoledronic acid after the first cycle of 5-fluorou-acil/epirubicin/cyclophosphamide (FEC) or treatmentith FEC alone. Patients will undergo serial repeat

umor biopsies and blood samples to assess the effectsn apoptosis, proliferation, and angiogenesis. The pri-ary outcome measure is increase in apoptotic index

etween diagnostic core biopsy and repeat core biopsyaken on day 5 (Table 2).

In support of these results, emerging evidence fromarge population-based retrospective analyses suggesthat both intravenous and oral bisphosphonates mighte associated with reduced risk for breast cancer.52,53

n the first age-adjusted analysis of data from the USomen’s Health Initiative (WHI) of 151,592 postmeno-

ausal women, of whom 2,216 were on bisphospho-ate therapy at study entry, oral bisphosphonate useas associated with a breast cancer rate of 3.29 per

,000 person-years compared to 4.38 per 1,000 person-ears in women who did not receive bisphosphonateherapy.52 This translates into a 32% reduction in thencidence of invasive breast cancers in patients onisphosphonate therapy (HR � 0.68, P �.01). More-ver, bisphosphonate therapy was also associated with30% lower incidence of receptor-positive breast can-

ers (HR � 0.70, P � .02). In another population-basednalysis of 4,575 postmenopausal women, bisphospho-ate use for 5 years or more was associated with anpproximately 30% reduction in incidence of breastancer compared to women not on bisphosphonateherapy.53 Moreover, hypothesis-generating results fromhese studies indicate that breast cancers that developn bisphosphonate therapy showed a higher likeli-ood of being associated with favorable tumor ch-racteristics.

Effect on circulating tumor cells. The prognosticignificance of circulating tumor cells in the bone mar-ow at primary diagnosis and following adjuvant ther-py has been described previously.54,55 It has beenostulated that the use of bisphosphonates to eradicatehe persisting isolated tumor cells might reduce the riskf recurrence. Recently, some clinical evidence hasccumulated to suggest that zoledronic acid may dem-nstrate antitumor effects on micrometastatic cells inhe bone marrow of patients with breast cancer whoave no other evidence of metastatic disease. In a studyf 172 primary breast cancer patients, with evidence ofancer cells in the bone marrow but no evidence ofistal recurrence, 31 patients were treated with

oledronic acid postoperatively and following adjuvant m

hemotherapy; bone marrow status was assessed atbout 8 and 12 months.56 Compared to the 141 controlatients, there was a significant reduction in theumber of circulating tumor cells detected betweenhe first and second aspirations with zoledronic acidherapy (P � .02 v P � .14). Preliminary data from amall study of 44 patients with early breast cancer alsoemonstrated that 1 year of treatment with zoledroniccid following neoadjuvant or adjuvant therapy de-reased the number of occult tumor cells in 73% ofatients.57 Recently, a phase II randomized single-cen-er experience with zoledronic acid in eliminating dis-eminated tumor cells (DTCs) from the bone marrow in20 patients with stage II–III newly diagnosed breastancer was reported. DTCs were detected at baselinen 26 of 60 patients in the zoledronic acid group and 28f 58 patients in the control group. Of these patients,7 of 56 patients receiving zoledronic acid showedetectable DTCs compared to 25 of 53 patients whoid not receive zoledronic acid (P � .054).58 Takenogether, these results suggest a potential antitumorffect of zoledronic acid therapy; large prospectiverials evaluating the benefit of using circulating tumorells as surrogate markers are warranted.

Prostate Cancer

Based on the encouraging clinical evidence of clin-cal benefit with adjuvant bisphosphonate therapy inatients with breast cancer, several trials have evalu-ted or are underway to determine if these clinicalenefits will extend to other tumor types as well. Inrostate cancer, PR04 was a randomized placebo-con-rolled trial of 508 patients that was initiated to deter-ine whether clodronate therapy improved clinical

utcomes in terms of symptomatic bone metastasis-freeurvival in men with nonmetastatic prostate cancerho were at high risk of developing bone metastases.t a median follow-up of about 10 years, clodronate

herapy did not show a difference in bone metastasis–ree survival (80 events v 68 events; HR � 1.22) or OS130 deaths v 127 deaths; HR � 1.02) compared tolacebo.59 The Medical Research Council (MRC) con-ucted two randomized trials PR04 and PR05 in 508en with nonmetastatic disease and 311 men withetastatic disease, respectively, to evaluate oral clodr-

nate treatment for 5 years and 3 years, respectively, inatients with prostate cancer.59,60 In an analysis of bothR04 and PR05, clodronate therapy in patients withetastatic disease was associated with a significant

ncrease in OS compared to placebo (HR � 0.77; 95%I, 0.60–0.98; P � .032). In patients with nonmeta-tatic disease, there was no improvement in OS in thewo treatment groups (HR � 1.12; 95% CI, 0.89–1.42;

� .94).60 By way of a partial explanation for theseontradictory results, it can be speculated that the

etastatic patient population is associated with an in-

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Antitumor effects and anticancer applications of bisphosphonates S37

reased tumor burden and a greater degree of oste-clast activity, and might be more susceptible toisphosphonate therapy compared to nonmetastaticumors that might have a more osteoblastic compo-ent. These results also lend support to the argumenthat the osteoclast activity in the predominantly osteo-lastic prostate cancers might be a consequence ofetastasis rather than a precursor for their genesis.Several prospective randomized trials are underway to

valuate the role of bisphosphonate therapy in preventingone metastasis in prostate cancer. In men with hor-one-sensitive disease, the European Association of Urol-

gy’s ongoing randomized Zoledronic acid EUropeantudy (ZEUS) trial is comparing the effect of standardormonal therapy with or without zoledronic acid, 4 mg

nfusions every 3 months for a total of 4 years, on preven-ion of bone metastasis in 1,433 high-risk patients withrostate cancer39 (Table 2). The Trans-Tasman Radiationncology Group’s Randomised Androgen Deprivationnd Radiotherapy (RADAR) trial is a four-arm trial that isomparing the effects of duration of androgen suppres-ion (for 5 or 18 months) and use of zoledronic acid (notiven or given as a 4 mg dose every 3 months for 18onths) on prostate-specific antigen (PSA) relapse-free

urvival in men receiving standard radiotherapy for pros-ate cancer.40 In addition, the Cancer and Leukemiaroup B (CALGB)–9202 trial is evaluating the effect of

oledronic acid (4 mg every 3 months for 18 months)ersus placebo in prevention of skeletal-related eventsSRE) in patients with hormone therapy–naïve metastaticrostate cancer.44

linical Evidence inatients With Multiple Myeloma

Bisphosphonates have been shown to significantlyeduce the incidence of skeletal complications in mul-iple myeloma. In particular, strong preclinical evi-ence attests to the antimyeloma effects of zoledroniccid. Therefore, it was hypothesized that zoledroniccid, in addition to its established benefits in prevent-ng skeletal complications, might also increase survivaln patients with multiple myeloma. In a subgroup anal-sis of patients enrolled into the placebo-controlledRC VIth Myeloma Study, McCloskey et al demon-

trated that clodronate might prolong survival in pa-ients without overt skeletal disease at presentation43

Table 3). At a median follow-up of 8.6 years, clodr-nate therapy was able to prevent the development ofew skeletal disease, but there was no overall signifi-ant difference in survival (P � .38). However, amonghe subgroup of 153 patients with no skeletal fracturest presentation, the 73 patients who received clodr-nate therapy achieved a significant improvement in-year survival advantage (46% v 35%; P � .006), withmedian survival of 59 months compared to the 37

onths with placebo alone. Considering the limitations t

f subgroup analyses, these observations require con-rmation in prospective clinical trials.

Early clinical evidence of the antitumor effects of bisphos-honates in multiple myeloma was reported by Aviles et al in4 previously untreated patients who were treated withither zoledronic acid or not following a conventional che-otherapy regimen of cyclophosphamide/vincristine/mel-halan/prednisone (CVMP).44 At the 5-year analysis,oledronic acid therapy was associated with a significantmprovement in EFS (80% v 50%; P �.01) and OS (80% v6%; P �.01). Patients who received zoledronic acid expe-ienced a lower rate of skeletal events compared to theontrol group. Thus, zoledronic acid along with chemother-py can increase EFS and OS and decrease the occurrence ofkeletal events in patients with previously untreated multipleyeloma.In a retrospective exploratory analysis of a large,

andomized, controlled trial in patients with multipleyeloma and bone lesions, the effects of zoledronic

cid and pamidronate on survival were assessed basedn baseline bone marker levels.45 In the overall popu-

ation of patients with multiple myeloma (N � 353),urvival was comparable between groups. However,n the subset of 212 patients who had a baselineone-specific alkaline phosphatase (BALP) assessment,oledronic acid demonstrated significant improvementn the 25-month OS (76% v 63%; P � .026), and signif-cantly reduced the risk of death by about 42% com-ared with pamidronate (P � .03). In a retrospectivetratification by baseline BALP levels, zoledronic acidas particularly effective in prolonging survival in pa-

ients with high baseline BALP compared to pamidr-nate (82% v 53%; P � .041). While these exploratoryesults are hypothesis-generating, prospective trials areeeded to validate these results.

The MRC Myeloma IX Study was initiated to pro-pectively evaluate the effect of zoledronic acid orlodronate therapy on survival endpoints of PFS and OSn 1,960 newly diagnosed patients with multiple my-loma. The results of this pivotal trial were recentlyresented at the 2010 annual meeting of the Americanociety of Clinical Oncology.46 At a median follow-up of.7 years, zoledronic acid therapy was associated withsignificant reduction in the proportion of patientsith an SRE compared to clodronate therapy (27.0% v

5.3%; P � .0004).46 Moreover, zoledronic acid therapyesulted in a significant 16% reduction in relative risk ofeath (HR � 0.842; P � .0118) and a 12% reduction inelative risk of progression (HR � 0.883; P � .0179)ompared to clodronate therapy. Importantly, the OSenefit associated with zoledronic acid appeared to be

ndependent of SRE prevention, as indicated by a 15%eduction in relative risk of death (HR � 0.85;

� .0178), suggesting that zoledronic acid might beediating its effects on survival primarily through an-

icancer activities. This landmark analysis represents

he first prospective trial data to support the early

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ntegration of bisphosphonates into treatment regi-ens in patients with newly diagnosed multiple myelo-a.46

Lung Cancer

Bone is one of the most frequent sites of metastasesn patients with lung cancer, occurring in about 20% to0% of cases. Preclinical evidence indicates thatoledronic acid augmented antitumor activity of cyto-oxic agents, including platinum salts and taxanes in aynergistic manner.61,62 Moreover, in animal models ofung metastasis, zoledronic acid exerted direct antitu-

or effects by slowing tumor growth, diminishing lungetastasis and prolonging OS.62,63 These results pro-

ide a strong rationale for development of combinationone-targeted therapies in halting disease progression

n lung cancer.64 In a randomized phase II study inatients with inoperable stage IIB or stage IV non-smallell lung cancer (NSCLC), addition of zoledronic acid tohemotherapy of docetaxel/carboplatin did not appearo provide any clinical benefit in terms of proportion ofatients without disease progression (41% v 39%;�.8096) and median time to progression (TTP; 132

ays v 132 days; P � .9622). One-year OS times andverall response rates were also similar between thewo treatment arms. No difference in TTP and OSetween the zoledronic arm and control were dis-erned in the follow-up phase of the study, whereesponding patients who received zoledronic acid ther-py in the initial phase of the study were re-randomizedo receive monthly zoledronic acid therapy for a max-mum of 12 months or no zoledronic acid. Althoughhese results do not support the clinical benefit ofdding zoledronic acid to chemotherapy in patientsith advanced NSCLC, their interpretation might haveeen influenced in part by lack of sufficient statisticalower, high rate of discontinuation, and short durationf therapy.64 In contrast, results from a Greek study of44 patients with stage IV lung cancer demonstratedhat addition of zoledronic acid to combination therapyf docetaxel/carboplatin significantly improved OSP �.01) compared to chemotherapy alone. Moreover,

statistically significant positive correlation betweenhe number of cycles of zoledronic acid therapy re-eived and survival (P �.01) and TTP (P �.01) wasdentified.65 An ongoing phase III trial (2419 study) isvaluating the effect of zoledronic acid in the preven-ion of bone metastases in patients with newly diag-osed, stage IIIA and stage IIIB NSCLC excluding pa-ients with pleural effusions.42 Secondary outcomeeasures include rate of bone metastasis at different

ime points, TTP, risk of SREs at 12 and 24 months fromtudy entry, and survival at 12 and 24 months.

ONCLUSIONS

Bisphosphonates are the cornerstone of the treat-

ent of SREs in many solid cancers with bone metas-

ases and myeloma bone disease. Emerging preclinicalnd clinical evidence indicates that bisphosphonatesdditionally exert direct and/or indirect antitumor ef-ects in many cancers. Moreover, some clinical evi-ence alludes to synergistic interactions betweenisphosphonates and cytotoxics. The expanded roleor bisphosphonates in the adjuvant setting has pro-ound clinical implications, and might herald a new eran the prevention of bone metastasis. A number of largengoing clinical trials are ongoing in various tumorypes to confirm the preclinical and early clinical sig-als of antitumor activity of bisphosphonates. Resultsrom these trials, if positive, would translate into newndications for bisphosphonate use in oncology.

TATEMENT OF CONFLICT OF INTEREST

G. Morgan: has no real or apparent conflicts ofnterest to disclose. A. Lipton discloses the followingotential conflicts of interest: Consulting fees: Amgennc; Cephalon, Inc; Novartis Pharmaceuticals Corpora-ion; and Thar Pharmaceuticals. Speaker’s bureau: Am-en Inc, Genentech, and Novartis Pharmaceuticals Cor-oration. Contracted research: Monogram Biosciences,ncogene Science/Siemens HealthCare Diagnostics,ovartis Pharmaceuticals Corporation. Expert testimony:ovartis Pharmaceutical Corporation.

cknowledgmenthe authors wish to thank Nathan Kelly, PhD, andrudy Grenon Stoddert, ELS, for their assistance inreparing the manuscript for publication.

EFERENCES1. Green JR. Bisphosphonates: preclinical review. Oncolo-

gist. 2004;9 Suppl 4:3–13.2. Winter MC, Holen I, Coleman RE. Exploring the anti-

tumour activity of bisphosphonates in early breast can-cer. Cancer Treat Rev. 2008;34:453–75.

3. Senaratne SG, Mansi JL, Colston KW. The bisphosphonatezoledronic acid impairs Ras membrane [correction of impairsmembrane] localisation and induces cytochrome c release inbreast cancer cells. Br J Cancer. 2002;86:1479–86.

4. Jagdev SP, Coleman RE, Shipman CM, Rostami HA,Croucher PI. The bisphosphonate, zoledronic acid, in-duces apoptosis of breast cancer cells: evidence for syn-ergy with paclitaxel. Br J Cancer. 2001;84:1126–34.

5. Boissier S, Magnetto S, Frappart L, et al. Bisphosphonatesinhibit prostate and breast carcinoma cell adhesion tounmineralized and mineralized bone extracellular matri-ces. Cancer Res. 1997;57:3890–4.

6. Boissier S, Ferreras M, Peyruchaud O, et al. Bisphospho-nates inhibit breast and prostate carcinoma cell invasion,an early event in the formation of bone metastases.Cancer Res. 2000;60:2949–54.

7. Virtanen SS, Väänänen HK, Härkönen PL, Lakkakorpi PT.Alendronate inhibits invasion of PC-3 prostate cancercells by affecting the mevalonate pathway. Cancer Res.

2002;62:2708–14.

1

1

1

1

1

1

1

1

1

1

2

2

2

2

2

2

2

2

2

2

3

3

3

3

3

3

3

3

3

Antitumor effects and anticancer applications of bisphosphonates S39

8. Denoyelle C, Hong L, Vannier JP, Soria J, Soria C. Newinsights into the actions of bisphosphonate zoledronicacid in breast cancer cells by dual RhoA-dependent and-independent effects. Br J Cancer. 2003;88:1631–40.

9. Fromigue O, Kheddoumi N, Body JJ. Bisphosphonatesantagonise bone growth factors’ effects on human breastcancer cells survival. Br J Cancer. 2003;89:178–84.

0. Wood J, Bonjean K, Ruetz S, et al. Novel antiangiogeniceffects of the bisphosphonate compound zoledronicacid. J Pharmacol Exp Ther. 2002;302:1055–61.

1. Croucher PI, De Hendrik R, Perry MJ, et al. Zoledronicacid treatment of 5T2MM-bearing mice inhibits the de-velopment of myeloma bone disease: evidence for de-creased osteolysis, tumor burden and angiogenesis, andincreased survival. J Bone Miner Res. 2003;18:482–92.

2. Bezzi M, Hasmim M, Bieler G, Dormond O, Rüegg C.Zoledronate sensitizes endothelial cells to tumor necrosisfactor-induced programmed cell death: evidence for the sup-pression of sustained activation of focal adhesion kinase andprotein kinase B/Akt. J Biol Chem. 2003;278:43603–14.

3. Santini D, Vincenzi B, Dicuonzo G, et al. Zoledronic acidinduces significant and long-lasting modifications of cir-culating angiogenic factors in cancer patients. Clin Can-cer Res. 2003;9:2893–7.

4. Dieli F, Gebbia N, Poccia F, et al. Induction of ��T-lymphocyte effector functions by bisphosphonatezoledronic acid in cancer patients in vivo. Blood. 2003;102:2310–1.

5. Kunzmann V, Bauer E, Feurle J, Weissinger F, Tony HP,Wilhelm M. Stimulation of �� T cells by aminobisphos-phonates and induction of antiplasma cell activity inmultiple myeloma. Blood. 2000;96:384–92.

6. Peyruchaud O, Winding B, Pécheur I, Serre CM, DelmasP, Clézardin P. Early detection of bone metastases in amurine model using fluorescent human breast cancercells: application to the use of the bisphosphonatezoledronic acid in the treatment of osteolytic lesions.J Bone Miner Res. 2001;16:2027–34.

7. Hiraga T, Williams PJ, Mundy GR, Yoneda T. Thebisphosphonate ibandronate promotes apoptosis inMDA-MB-231 human breast cancer cells in bone metas-tases. Cancer Res. 2001;61:4418–24.

8. Sasaki A, Boyce BF, Story B, et al. Bisphosphonate risedr-onate reduces metastatic human breast cancer burden inbone in nude mice. Cancer Res. 1995;55:3551–7.

9. Sasaki A, Kitamura K, Alcalde RE, et al. Effect of a newlydeveloped bisphosphonate, YH529, on osteolytic bonemetastases in nude mice. Int J Cancer. 1998;77:279–85.

0. Hiraga T, Williams PJ, Ueda A, Tamura D, Yoneda T.Zoledronic acid inhibits visceral metastases in the 4T1/lucmouse breast cancer model. Clin Cancer Res. 2004;10:4559–67.

1. Daubiné F, Le Gall C, Gasser J, Green J, Clezardin P.Antitumor effects of clinical dosing regimens of bisphos-phonates in experimental breast cancer bone metastasis.J Natl Cancer Inst. 2007;99:322–30.

2. Diel IJ, Solomayer EF, Costa SD, et al. Reduction in newmetastases in breast cancer with adjuvant clodronatetreatment. N Engl J Med. 1998;339:357–63.

3. Diel IJ, Jaschke A, Solomayer EF, et al. Adjuvant oral clodronate

improves the overall survival of primary breast cancer patients 3

with micrometastases to the bone marrow: a long-termfollow-up. Ann Oncol. 2008;19:2007–11.

4. Diel IJ. Bisphosphonates in the prevention of bone me-tastases: current evidence. Semin Oncol. 2001;28:75–80.

5. Powles T, Paterson S, Kanis JA, et al. Randomized, pla-cebo-controlled trial of clodronate in patients with pri-mary operable breast cancer. J Clin Oncol. 2002;20:3219–24.

6. Powles T, Paterson A, McCloskey E, et al. Reduction inbone relapse and improved survival with oral clodron-ate for adjuvant treatment of operable breast cancer[ISRCTN83688026]. Breast Cancer Res. 2006;8:R13.

7. Saarto T, Blomqvist C, Virkkunen P, Elomaa I. Adjuvantclodronate treatment does not reduce the frequency ofskeletal metastases in node-positive breast cancer pa-tients: 5-year results of a randomized controlled trial.J Clin Oncol. 2001;19:10–7.

8. Kokufu I, Kohno N, Takao S, Yamamoto M, et al. Adju-vant pamidronate (PMT) therapy for the prevention ofbone metastasis in breast cancer (BC) patients (pts) withfour or more positive nodes [abstract 530]. J Clin Oncol.2004;22:14S.

9. Jung J, Hwang G, Lee Y, Park H, Yang Y. Pamidronate asadjuvant treatment for prevention of bone metastasis inbreast cancer [abstract]. J Clin Oncol 2005;23 suppl 16:Abstract 888.

0. Eidtmann H, de Boer R, Bundred N, et al. Efficacy ofzoledronic acid in postmenopausal women with earlybreast cancer receiving adjuvant letrozole: 36-month re-sults of the ZO-FAST Study. Ann Oncol 2010 May 5.[Epub ahead of print].

1. Gnant M, Mlineritsch B, Schippinger W, et al. ABCSG-12Trials Investigators. Endocrine therapy plus zoledronicacid in premenopausal breast cancer. N Engl J Med.2009;360:679–91.

2. Coleman RE, Winter MC, Cameron D, et al. The effects ofadding zoledronic acid to neoadjuvant chemotherapy on tu-mour response: exploratory evidence for direct anti-tumouractivity in breast cancer. Br J Cancer. 2010;102:1099–105.

3. Saarto T, Vehmanen L, Virkkunen P, Blomqvist C. Ten-year follow-up of a randomized controlled trial of adju-vant clodronate treatment in node-positive breast cancerpatients. Acta Oncol. 2004;43:650–6.

4. Ha TC, Li H. Meta-analysis of clodronate and breast can-cer survival. Br J Cancer. 2007;96:1796–801.

5. Coleman RE. Emerging strategies in bone health managementfor the adjuvant patient. Semin Oncol. 2007;34 suppl 4:S11–6.

6. ClinicalTrials.gov. Clodronate with or without chemo-therapy and/or hormonal therapy in treating womenwith stage I or II breast cancer. Available at: http://clinicaltrials.gov/ct2/show/NCT00009945. Accessed Au-gust 20, 2010.

7. ClinicalTrials.gov. Zoledronate, clodronate, or ibandr-onate in treating women who have undergone surgeryfor stage I, stage II, or stage III breast cancerr. Availableat: http://clinicaltrials.gov/ct2/show/NCT00127205. Ac-cessed July 10, 2010.

8. ClinicalTrials.gov. Postoperative use of zoledronic acidin breast cancer patients after neoadjuvant chemother-apy (NATAN). Available at: http://clinicaltrials.gov/ct2/show/NCT00512993 Accessed July 10, 2010.

9. Wirth M, Tammela T, Debruyne F, Tubaro A. Effective-

4

4

4

4

4

4

4

4

4

4

5

5

5

5

5

5

5

5

5

5

6

6

6

6

6

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S40 G. Morgan and A. Lipton

ness of zoledronic acid for the prevention of bonemetastases in high-risk prostate cancer patients. Arandomised, open label, multicenter study of theEuropean Association of Urology (EAU) in Cooperationwith the Scandinavian Prostate Cancer Group (SPCG)and the Arbeitsgemeinschaft Urologische Onkologie(AUO). A report of the ZEUS study [abstract 184]. Pre-sented at: 2008 Genitourinary Cancer Symposium; Feb-ruary 14–16, 2008; San Francisco, CA.

0. ClinicalTrials.gov RADAR Trial—Randomised androgen depri-vation and radiotherapy. Available at: http://clinicaltrials.gov/ct2/show/NCT00193856. Accessed July 10, 2010.

1. ClinicalTrials.gov. Zoledronate in preventing skeletal(bone)-related events in patients who are receiving an-drogen deprivation therapy for prostate cancer and bonemetastases. Available at: http://clinicaltrials.gov/ct2/show/NCT00079001. Accessed July 10, 2010.

2. ClinicalTrials.gov. A study to evaluate the safety andefficacy of zoledronic acid in the prevention or delayingof bone metastasis in patients with stage IIIA and IIIBnon-small cell lung cancer. Available at: http://www.clinicaltrials.gov/ct2/show/NCT00172042. AccessedJuly 10, 2010.

3. McCloskey EV, Dunn JA, Kanis JA, MacLennan IC, Dray-son MT. Long-term follow-up of a prospective, double-blind, placebo-controlled randomized trial of clodronatein multiple myeloma. Br J Haematol. 2001;113:1035–43.

4. Avilés A, Nambo MJ, Neri N, Castañeda C, Cleto S,Huerta-Guzman J. Antitumor effect of zoledronic acid inpreviously untreated patients with multiple myeloma.Med Oncol. 2007;24:227–30.

5. Berenson JR, Dimopoulous MA, Chen Y-M, et al.Zoledronic acid may improve survival compared to pam-idronate in patients with MM and high BALP levels:univariate and multivariate models of hazard ratios [ab-stract]. Blood 2006;108: Abstract 3589.

6. Morgan G, Davies F, Gregory W, et al. Evaluating theeffects of zoledronic acid (ZOL) on overall survival (OS)in patients (Pts) with multiple myeloma (MM): Results ofthe Medical Research Council (MRC) Myeloma IX study[abstract]. J Clin Oncol 2010;28 suppl 15: Abstract 8021.

7. van Holten-Verzantvoort AT, Hermans J, Beex LV, et al.Does supportive pamidronate treatment prevent or de-lay the first manifestation of bone metastases in breastcancer patients? Eur J Cancer. 1996;32A:450–4.

8. Mystakidou K, Katsouda E, Parpa E, Kelekis A, Galanos A,Vlahos L. Randomized, open label, prospective study onthe effect of zoledronic acid on the prevention of bonemetastases in patients with recurrent solid tumors thatdid not present with bone metastases at baseline. MedOncol. 2005;22:195–201.

9. Brufsky A, Bundred N, Coleman R, et al. Z-FAST andZO-FAST Study Group. Integrated analysis of zoledronicacid for prevention of aromatase inhibitor-associated boneloss in postmenopausal women with early breast cancerreceiving adjuvant letrozole. Oncologist. 2008;13:503–14.

0. Coleman R, Bundred N, De Boer R, et al. Impact ofzoledronic acid in postmenopausal women with earlybreast cancer receiving adjuvant letrozole: Z-FAST, ZO-FAST, and E-ZO-FAST [abstract]. Cancer Res 2009;69

suppl 24: Abstract 4082.

1. National Osteoporosis Foundation: Clinician’s guide toprevention and treatment of osteoporosis. Available at:http://www.nof.org/professionals/NOF_Clinicians_Guide.pdf. Accessed June 27, 2010.

2. Chlebowski RT, Chen Z, Cauley JA, Rodabough RJ. OralBisphosphonate and breast cancer: prospective resultsfrom the Women’s Health Initiative (WHI) [abstract].Cancer Res 2009;69 suppl 24: Abstract 21.

3. Rennert G, Pinchev M, Rennert H, et al. Use of bisphos-phonates and risk of postmenopausal breast cancer [ab-stract]. Cancer Res 2009;69 suppl 24: Abstract 27.

4. Braun S, Vogl FD, Naume B, et al. A pooled analysis ofbone marrow micrometastasis in breast cancer. N EnglJ Med. 2005;353:793–802.

5. Janni W, Rack B, Schindlbeck C, et al. The persistence ofisolated tumor cells in bone marrow from patients withbreast carcinoma predicts an increased risk for recur-rence. Cancer. 2005;103:884–91.

6. Rack B, Jückstock J, Genss EM, et al. Effect of zoledr-onate on persisting isolated tumour cells in patients withearly breast cancer. Anticancer Res. 2010;30:1807–13.

7. Lin A, Park J, Melisko, et al. Zoledronic acid as adjuvanttherapy for women with early stage breast cancer andoccult tumor cells in bone marrow [abstract]. BreastCancer Res Treat 2007;106 suppl 1: Abstract 510.

8. Aft R, Naughton M, Trinkaus K, et al. Effect of zoledronicacid on disseminated tumour cells in women with locallyadvanced breast cancer: an open label randomised,phase 2 trial [abstract]. J Clin Oncol 2008;26 May 20suppl: Abstract 1021.

9. Mason MD, Sydes MR, Glaholm J, et al. Medical ResearchCouncil PR04 Collaborators. Oral sodium clodronate fornonmetastatic prostate cancer—results of a randomizeddouble-blind placebo-controlled trial: Medical ResearchCouncil PR04 (ISRCTN61384873). J Natl Cancer Inst.2007;99:765–76.

0. Dearnaley DP, Mason MD, Parmar MK, Sanders K, Sydes MR.Adjuvant therapy with oral sodium clodronate in locally ad-vanced and metastatic prostate cancer: long-term overall sur-vival results from the MRC PR04 and PR05 randomised con-trolled trials. Lancet Oncol. 2009;10:872–6.

1. Ozturk OH, Bozcuk H, Burgucu D, et al. Cisplatin cyto-toxicity is enhanced with zoledronic acid in A549 lungcancer cell line: preliminary results of an in vitro study.Cell Biol Int. 2007;31:1069–71.

2. Matsumoto S, Kimura S, Segawa H, et al. Efficacy of thethird-generation bisphosphonate, zoledronic acid aloneand combined with anti-cancer agents against small celllung cancer cell lines. Lung Cancer. 2005;47:31–9.

3. Ory B, Heymann MF, Kamijo A, Gouin F, Heymann D,Redini F. Zoledronic acid suppresses lung metastasesand prolongs overall survival of osteosarcoma-bearingmice. Cancer. 2005;104:2522–9.

4. Pandya KJ, Gajra A, Warsi GM, Argonza-Aviles E, Ericson SG,Wozniak AJ. Multicenter, randomized, phase 2 study ofzoledronic acid in combination with docetaxel and carbopla-tin in patients with unresectable stage IIIB or stage IV non-small cell lung cancer. Lung Cancer. 2010;67:330–8.

5. Zarogoulidis K, Boutsikou E, Zarogoulidis P, et al. The impactof zoledronic acid therapy in survival of lung cancer patients

with bone metastasis. Int J Cancer. 2009;125:1705–9.