1513P - Risk factors for hypocalcemia in patients with cancer receiving denosumab

Date 28 September 2014
Event ESMO 2014
Session Poster Display session
Topics Complications of Treatment
Supportive Care
Presenter Jean-Jacques Body
Citation Annals of Oncology (2014) 25 (suppl_4): iv517-iv541. 10.1093/annonc/mdu356
Authors J. Body1, H.G. Bone2, C. van Poznak3, R.H. De Boer4, A. Stopeck5, R. Damião6, K. Fizazi7, D.H. Henry8, T. Ibrahim9, A. Lipton10, F. Saad11, N.D. Shore12, T. Takano13, H. Wang14, O.L. Bracco15, A. Balakumaran16, P.J. Kostenuik17
  • 1Medicine, Centre Hospitalier Universitaire BrugmannUniversit, BE-1020 - Brussels/BE
  • 2Endocrinology, Michigan Bone and Mineral Clinic, 48236 - Detroit/US
  • 3Comprehensive Cancer Center, University of Michigan, 48109 - Ann Arbor/US
  • 4Department Of Medical Oncology, Royal Melbourne Hospital, Parkville/AU
  • 5Clinical Breast Cancer Program, University of Arizona Cancer Center, Tucson/US
  • 6Urology, Hospital Universitario Pedro Ernesto, Rio de Janeiro/BR
  • 7Department Of Cancer Medicine, Institut Gustave Roussy, University of Paris Sud, Villejuif/FR
  • 8Joan Karnell Cancer Center, Pennsylvania Hospital, Philadelphia/US
  • 9Oncology, IRCCS-Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori, Meldola/IT
  • 10Division Of Hematology/oncology, Pennsylvania State University, Milton S Hershey Medical Center, US-17033 - Hershey/US
  • 11Surgery, University of Montreal Hospital Center, H2L4M1 - Montreal/CA
  • 12Urology, Carolina Urologic Research Center, Myrtle Beach/US
  • 13Dept. Of Medical Oncology, Toranomon Hospital, JP-105-8470 - Tokyo/JP
  • 14Global Biostatistical Science, Amgen, 91320 - Thousand Oaks/US
  • 15Safety, Amgen, 91320 - Thousand Oaks/US
  • 16Global Development, Amgen, 91320 - Thousand Oaks/US
  • 17Metabolic Disorders, Amgen, 91320 - Thousand Oaks/US

Abstract

Aim

The potent RANK ligand inhibitor denosumab (Dmab) can cause hypocalcemia (hypoCa). Patients (pts) with inadequate intake of Ca and vitamin D are at increased risk for hypoCa. Additional baseline risk factors for hypoCa in pts with metastatic bone disease (MBD) were evaluated to aid clinical risk assessment for this adverse event.

Methods

A post hoc analysis used data from three identically designed, randomized, blinded phase 3 trials comparing monthly dosing of 4 mg zoledronic acid (ZA) to 120 mg Dmab in pts with MBD to identify lab events of grade≥2 hypoCa (CTCAE:<8.0–7.0 mg/dL;<2.0–1.75 mmol/L). Pt characteristics evaluated included: gender, race (white vs non-white), tumor type, bone lesion type (osteolytic, osteoblastic, mixed), baseline calculated creatinine clearance (CrCl), # of bone mets, and baseline bone-specific alkaline phosphatase (BSAP) and urinary N-telopeptide (uNTx) levels.

Results

The overall incidence of lab grade≥2 hypoCa events in those treated with Dmab was equal to or greater than in those treated with ZA and occurred in 12.4% of Dmab-treated pts. Baseline pt characteristics with the greatest incidence of hypoCa include: male gender (15.4%), prostate cancer (20.5%), small cell lung cancer (18.0%), and CrCl 30 –<60 ml/min (15.5%). The risk of developing hypoCa was increased in pts with>2 bone mets and those with higher BSAP or uNTx levels (Table). Osseous lesion type did not significantly increase the risk of developing hypoCa (P ≥ 0.23).

Baseline Factor HazardRatio 95% CI P-value
> 2 bone mets 1.329 (1.044, 1.692) 0.021
BSAP>median (20.77 &mgr;g/L) 2.078 (1.579, 2.734) <.0001
BSAP>median vs≤median
> 2 bone mets 4.236 (2.117, 8.479)
≤ 2 bone mets 1.773 (1.312, 2.395)
Interaction of baseline BSAP and # of bone mets 0.021
uNTX>50 nmol/mmol 1.316 (1.031, 1.680) 0.027
Interaction of baseline uNTX and # of bone mets 0.21

Conclusions

The risk of hypoCa after Dmab for MBD is associated with the # of bone mets and elevated bone turnover markers, especially high BSAP with>2 mets. BSAP may indicate the potential for deposition of Ca in undermineralized matrix. Pts with high bone turnover may be more susceptible to hypoCa when osteoclasts are rapidly inhibited, particularly when Ca and vitamin D intake is insufficient.

Disclosure

J. Body: Consultant for and received research funding from Amgen; received honoraria from Amgen and Novartis; H.G. Bone: Consultant for and received honoraria from Amgen and Novartis; C. van Poznak: Received research funding from Amgen and Novartis; R.H. De Boer: Consultant for and received honoraria from Novartis; received research funding and other remuneration from Amgen and Novartis; A. Stopeck: Consultant for Amgen; honoraria from Amgen and GlaxoSmithKline; research funding from Amgen and Novartis; K. Fizazi: Consultant for Amgen and Novartis; honoraria from Amgen; D.H. Henry: Consultant for and received research funding and honoraria from Amgen, Ortho Biotech, and Watson; T. Ibrahim: Consultant for Amgen; A. Lipton: Honoraria and research funding from Amgen; F. Saad: Consultant for and received research funding and honoraria from Amgen and Novartis; N.D. Shore: Consultant for Amgen, Astellas, Bayer, Dendreon, Janssen, and Medivation; T. Takano: Consultant for and received honoraria from Daiichi-Sankyo; H. Wang: Employee of and owns stock or stock options in Amgen; O.L. Bracco: Employee of and owns stock or stock options in Amgen; A. Balakumaran: Employee of and owns stock or stock options in Amgen; P.J. Kostenuik: Employee of and owns stock or stock options in Amgen. All other authors have declared no conflicts of interest.