Safety and efficacy of repeat administration of samarium Sm-153 lexidronam to patients with metastatic bone pain.
BACKGROUND
Samarium Sm 153 lexidronam (Sm-153) is an effective and well-tolerated treatment for painful bone metastases. The purpose of the analysis was to assess the safety and efficacy of repeated doses of Sm-153 in patients with metastatic bone pain.


METHODS
Data were collected prospectively for 202 patients administered 1.0 mCi/kg of Sm-153. Particular emphasis was placed on analysis of data from 55 patients receiving > or = 2 doses. Pain scores, adverse events, and hematologic parameters were assessed after each dose.


RESULTS
Mild, transient suppression of platelets and white blood cell counts was the most common adverse event after treatment. Nadirs were approximately half of baseline at 4 weeks after dosing with recovery by Week 8 in 90% of patients. Temporary grade 3 thrombocytopenia occurred in 11%, 12%, and 17% of patients after the first, second, and third drug administration, respectively. Grade 3 leukopenia occurred in less than 7% of patients independent of the number of administrations. Significant decreases in pain scores (P < .001) were observed at Week 4 after each of the first 3 doses and maintained at Week 8 after the first 2 doses (P < .003) but not the third. Decreases in pain scores were observed in 70%, 63%, and 80% of patients, respectively, at Week 4 after the first 3 administrations.


CONCLUSIONS
Repeated dosing of 1.0 mCi/kg of Sm-153 was both safe and effective and is a reasonable treatment option in patients whose bone pain responds and then recurs after an initial dose provided that adequate hematologic function is present at the time of drug administration.
Sartor
Oliver
O
Lank Center for Genitourinary Oncology, Dana Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA. oliver_sartor@dfci.harvard.edu
Reid
Robert H
RH
Bushnell
David L
DL
Quick
Donald P
DP
Ell
Peter J
PJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018712:Analgesics, Non-Narcotic / Q000627:therapeutic use*; D001859:Bone Neoplasms / Q000188:drug therapy* / Q000556:secondary; D001943:Breast Neoplasms / Q000188:drug therapy / Q000473:pathology; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds / Q000627:therapeutic use*; D009943:Organophosphorus Compounds / Q000627:therapeutic use*; D010146:Pain / Q000188:drug therapy*; D010147:Pain Measurement; D010166:Palliative Care; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000473:pathology; D012449:Safety; D012493:Samarium / Q000627:therapeutic use
D018712:Analgesics, Non-Narcotic; D009942:Organometallic Compounds; D009943:Organophosphorus Compounds; D012493:Samarium; C061972:samarium Sm-153 lexidronam