Severe Hypocalcemia Following Denosumab Injection in a Hemodialysis Patient

Denosumab associated with bone density increase and clinical improvement in a long-term hemodialysis patient. Case report and review of the literature

Denosumab is a human monoclonal antibody representing a novel therapy of osteoporosis. Contrary to always other antiosteoporotic drugs, it is not contraindicated in advanced chronic kidney disease, as its pharmacokinetic does not differ from patients with normal kidney function. However, published case reports in chronic kidney disease (CKD) patients stopped the therapy after single dose because of hypocalcemia. We present a case of successful treatment of osteoporosis in a young hemodialysis patient with repeated denosumab doses.

Adverse events across generations of bone-modifying agents in patients with solid tumor cancers reported in Phase III randomized trials

AIMS

The objective of this study is to compare adverse events experienced among different bone-modifying agents.

METHODS

A literature search was conducted to identify Phase III bisphosphonate and bone-modifying agent trials reporting adverse effects. Thirty-seven adverse events of interest were identified for six different treatment options. Weighted linear regression modeling was performed on the adverse event proportions with treatment groups, normalized through applying natural log transformations.

RESULTS

There were significant differences in adverse events of vomiting (p = 0.045) and osteonecrosis of the jaw (p = 0.017), and combined item events of nausea/vomiting (p = 0.048), hematological and lymphatic system toxicities (p = 0.020), and any respiratory system problem (p = 0.023) between bone-modifying agent and placebo trials. The significant toxicities were observed even after adjusting for the two confounding factors of age and primary cancer site.

CONCLUSION

While adverse effects are consistently experienced more frequently in patients receiving bone-modifying agents when compared with placebos, we find that the majority of individual side effects are not significantly more frequent in patients receiving bone-modifying agents compared with placebo.

Severe Hypocalcemia due to Denosumab in Metastatic Prostate Cancer

Denosumab is a monoclonal antibody used for prevention of skeletal-related events (SREs) in patients with bone metastases from solid tumors. Hypocalcemia is a rare and dangerous side effect of the drug Denosumab. We present a case of a patient with metastatic prostate cancer who developed severe hypocalcemia after the administration of the drug. The patient's vitamin D levels were low when checked after administration of the drug, which likely predisposed him to the development of hypocalcemia. He was placed on high doses of oral and intravenous (IV) calcium and vitamin D without any appreciable response in the serum calcium level. His ionized calcium remained below 0.71 mmol/L despite very high doses of oral and IV calcium supplements. During the hospital course, he developed hydronephrosis from the spread of a tumor and did not want to undergo percutaneous nephrostomy tube placement; therefore, it was decided to dialyse him for acute renal failure and to correct his hypocalcemia. Checking calcium and vitamin D levels prior to the administration of Denosumab is vital in preventing hypocalcemia. If hypocalcemia is severe and not responsive to high doses of vitamin D, oral and IV calcium, then hemodialysis with a high calcium bath can correct this electrolyte abnormality.

Severe hypocalcemia after denosumab in a patient with acquired Fanconi syndrome

We report the case of a 48-year-old man with acquired Fanconi syndrome due to IgG-kappa monoclonal gammopathy, who received a single dose of denosumab 60 mg for secondary prevention of skeletal fractures, in conjunction with oral calcium and vitamin D supplementation. The treatment was complicated with a severe, symptomatic hypocalcemia occurring 1 month after the injection and necessitating 4 weeks of intravenous calcium gluconate therapy. Similarly to bisphosphonates, inhibitors of the receptor activator of nuclear factor kappa-B ligand may not be appropriate for the treatment of acquired Fanconi syndrome and other forms of osteomalacia regardless of the degree of renal insufficiency and vitamin D levels. Clinicians should carefully interpret the radiographic and bone densitometry results in light of diverse mechanisms of bone demineralization and potential dependence of calcium homeostasis on high bone turnover.

Acute severe hypercalcemia after traumatic fractures and immobilization in hypophosphatasia complicated by chronic renal failure

CONTEXT

Hypophosphatasia (HPP) features deficient activity of the "tissue-nonspecific" isoenzyme of alkaline phosphatase (TNSALP) due to loss-of-function mutation(s) within the TNSALP gene. Consequently, inorganic pyrophosphate, a TNSALP substrate and inhibitor of mineralization, accumulates extracellularly. This can cause rickets or osteomalacia.

OBJECTIVE

We report a 55-year-old man with HPP and chronic renal failure (CRF) requiring hemodialysis who developed severe hypercalcemia acutely after traumatic fractures and immobilization. He manifested HPP in childhood and in middle age received hemodialysis for CRF attributed to hypertension and anti-inflammatory medication. He took 2 g of calcium carbonate orally each day to bind dietary phosphorus, but never aluminum hydroxide or any form of vitamin D. Pretrauma serum levels of calcium spanned 8.4-10.7 mg/dL (normal [Nl], 8.6-10.3), inorganic phosphate 5.8-6.4 mg/dL (Nl, 2.5-4.5), and PTH 63-75 pg/mL (Nl, 10-55).

RESULTS

Rapid succession falls fractured multiple major bones. Six hours later, he became confused. Serum calcium was 14.9 mg/dL, ionized calcium was 7.4 mg/dL (Nl, 4.5-5.1), and PTH was 16 pg/mL. Hemodialysis quickly corrected his hypercalcemia and confusion. Low serum alkaline phosphatase persisted, and follow-up skeletal histopathology showed that his osteomalacia was severe.

CONCLUSION

Hemodialysis does not heal the skeletal disease of HPP. During sudden fracture immobilization in HPP, sufficient calcium can emerge from bone, perhaps from a rapidly exchangeable calcium pool, to cause acute severe hypercalcemia if the kidneys cannot compensate for the mineral efflux. Hence, we worry that acute hypercalcemia might accompany sudden immobilization in CRF patients without HPP if they have adynamic bone disease.

Incidence and risk of denosumab-related hypocalcemia in cancer patients: a systematic review and pooled analysis of randomized controlled studies

PURPOSE

The aim of this study is to evaluate the frequency and relative risk of hypocalcemia in cancer patients receiving denosumab.

METHODS

We searched the PubMed (data from 1966 to October 2012), Embase (data from 1980 to October 2012) and Cochrane Library (up to October 2012) electronic databases for relevant randomized controlled trials (RCTs). Abstracts presented at conferences were also searched. Phase II and III trials of denosumab in patients with any type of cancer that reported occurrence of hypocalcemia were eligible. Overall incidence rates, relative risk (RR), and 95% confidence intervals (CI) were calculated employing fixed- or random-effects models depending on the heterogeneity among included trials.

RESULTS

A total of 8990 patients with a variety of solid tumors from seven RCTs were included for the meta-analysis. The overall incidences of all-grade and high-grade hypocalcemia in cancer patients were 5.2% (95% confidence interval [CI]: 2.8-9.3%) and 2.0% (95% CI: 0.7-5.5%), respectively. The use of denosumab was associated with significantly increased risk of developing all-grade (RR 1.932, 95% CI: 1.590-2.347, p < 0.001) and high-grade hypocalcemia (RR 4.027, 95% CI: 2.346-6.912, p < 0.001) in comparison with controls.

CONCLUSIONS

The use of denosumab is associated with a significantly increased risk of developing hypocalcemia (p < 0.001). Physicians should be aware of this adverse effect and should monitor cancer patients receiving denosumab.

Prolonged hypocalcemia following denosumab therapy in metastatic hormone refractory prostate cancer

Prostate cancer is a leading cause of cancer death, frequently associated with widespread bone metastases. We report two cases of hypocalcemia following the first dose of denosumab in metastatic hormone refractory prostate cancer, the first case requiring 26 days of intravenous calcium therapy. This is the first report of prolonged hypocalcemia following denosumab in a patient with normal renal function.