Phase I evaluation of CycloSam® (Sm-153-DOTMP) bone seeking radiopharmaceutical in dogs with spontaneous appendicular osteosarcoma.

153 Sm-DOTMP (CycloSam® ) is a newly-patented radiopharmaceutical for bone tumor treatment. DOTMP (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylene-phosphonate) is a macrocyclic chelating agent with superior binding properties to 153 Sm when compared with EDTMP (Quadramet™, used for palliative treatment of bone cancer). CycloSam® was administered at 1 mCi/kg (37 MBq/kg) in a prospective pilot study to seven dogs with bone cancer resulting in no myelosuppression. Then, 13 dogs were enrolled in a prospective clinical trial study using traditional 3+3 dose escalation and starting at 1.5 mCi/kg. Baseline evaluation included hematologic and biochemical testing, diagnosis confirmation, thoracic and limb radiographs, technetium-99 m-HDP bone scintigraphy, and 18 F-FDG PET scan (SUVmax). Toxicity (primary endpoint) was assessed through weekly blood counts and adverse events. Dogs received 1.5 mCi/kg (n = 4), 1.75 mCi/kg (n = 6), and 2 mCi/kg (n = 3) of 153 Sm-DOTMP. Dose-limiting neutropenia and thrombocytopenia were seen at 2 mCi/kg. No dose-limiting nonhematologic toxicities occurred. Efficacy (secondary endpoint) was assessed by objective lameness measurement (body-mounted inertial sensors), owner quality-of-life (QoL) questionnaire, and repeat PET scan. Objective lameness measurement improved in four dogs (53%-60% decrease) was equivocal in three dogs, and worsened in four dogs (66%-115% increase); two dogs were not evaluable. Repeat 18 F-FDG PET scan results varied and change in lameness did not consistently correlate with SUVmax changes. QoL score worsened (n = 5) or was improved/stable (n = 7). Carboplatin chemotherapy (300 mg/m2 IV every 3 weeks ×4) started 4 weeks after 153 Sm-DOTMP injection. No dog died of chemotherapy-related complications. All dogs completed study monitoring. The recommended dose for CycloSam® in dogs is 1.75 mCi/kg, which resulted in some pain control with minimal toxicity and was safely combined with chemotherapy.

Knee radiosynovectomy with 153Sm-hydroxyapatite compared to 90Y-hydroxyapatite: initial results of a prospective trial.

INTRODUCTION: Radiosynovectomy (RS) with 90Y-hydroxyapatite (90Y-HyA) aims to control knee hemarthrosis in hemophiliac patients to prevent secondary arthropathy. However, knee RS using 153Sm-hydroxyapatite (153Sm-HyA) is considered less suitable due to the lower average soft tissue range and energy of 153Sm for large joints, such as the knees. PURPOSE: The objective of this investigation was to assess the efficacy and safety of knee RS with 153Sm-HyA, compared to 90Y-HyA. METHODS: Forty patients were prospectively assigned to undergo knee RS with 153Sm-HyA (n = 19) or with 90Y-HyA (n = 21). The frequency of hemarthrosis episodes before and after treatment were compared. RESULTS: After six months of knee RS, 153Sm-HyA and 90Y-HyA promoted a similar reduction of hemarthrosis episodes (50% and 66.7%, respectively). However, after 12 months of knee RS, the reduction of hemarthrosis episodes was significantly (p = 0.037) higher using 153Sm-HyA (87.5%) compared to 90Y-HyA (50.0%). This discrepancy was more pronounced (p = 0.002) for 153Sm-HyA compared to 90Y-HyA in adults/adolescents. CONCLUSION: Knee radiosynovectomy with 153Sm-HyA is safe, reduces hemarthrosis episodes after 12 months of treatments, especially in adults/adolescents and even with grades III/IV arthropathy, similar to 90Y-HyA. 90Y-HyA seems to promote better hemarthrosis control in small children.

Samarium enriches antitumor activity of ZnO nanoparticles via downregulation of CXCR4 receptor and cytochrome P450.

Cancer is the leading cause of death and exhausts human and economic resources for treatment and protection. Zinc oxide nanoparticles play an effective role in tumor treatment but with some cautions, such as overexpression of cytochrome P450, hepatic overload, and the mammalian target of rapamycin pathway resistance. Although lanthanides have antitumor activity, their use is limited. Therefore, the current study aims to improve the effectiveness of zinc oxide nanoparticle via doping with lanthanides, such as samarium. In vitro study revealed that samarium doped with zinc oxide showed more antitumor activity than the other lanthanides, and the antitumor activity depends on the concentration of samarium in the nanocomposite. The in vivo experiment on mice bearing Ehrlich solid tumor revealed that intramuscular injection of samarium/zinc oxide downregulates the expressions of CXCR4 and PI3K/Akt/mammalian target of rapamycin pathway in respect to Ehrlich solid tumor group. Regarding the apoptotic biomarkers, samarium/zinc oxide upregulates the apoptotic biomarker; Bax accompanied with the mitotic catastrophe which was indicated by cell cycle arrest in G2 phase. Moreover, samarium:zinc oxide nanoparticles exhibited minimum toxicity which was indicated by suppressed activities of cytochrome P450 and hepatic enzymes, including alanine transaminase and aspartate transaminase. In addition, the histopathological finding, as well as immunophenotyping results, appreciated the biochemical finding. Therefore, samarium:zinc oxide might be offered a new approach to improve the effectiveness of zinc oxide nanoparticles along with lower toxic effect. Also, samarium:zinc oxide nanoparticles can be a candidate as a new antitumor compound to detect its mode of action.

Radioactive synovectomy with (90) yttrium and (153) samarium hydroxyapatite in haemophilic joints: preliminary study on radiation safety.

Most countries still do not achieve 1 IU of factor VIII/capita sufficient for survival. Although primary prophylaxis prevents synovitis, is not universally used. Chronic synovitis is treated with arthroscopy at expense of considerable amount of coagulation factors, and specialized surgeons. Radioactive synovectomy (RS) is a minimally invasive and cost effective alternative to arthroscopy, often considered first the option for persistent synovitis. Even without established causation with cancer, RS is avoided by some, due to this concern. We aim contributing to the understanding of RS safety regarding malignancy, presenting a large number of treated patients, and a single case of cancer. Three centres in Brazil applied RS with (90) Yttrium Citrate, (90) Yttrium hydroxyapatite or (153) Samarium hydroxyapatite in haemophilic joints and performed a survey addressing cancer in these patients. Four hundred and eighty eight patients (ages 3-51) received 1-3 RS (total 842) and follow-up was 6 months to 9 years. One patient aged 14 years presented Ewing sarcoma, 11 months after RS. The tumour was treated successfully with surgery and chemotherapy. Causality of cancer by RS is improbable in this case. Accordingly, latency here is far below minimum 5-10 years for radio-induction of solid tumours. Moreover, ES is not a typically radio-induced tumour, even at high doses. In agreement with others, though recognizing limitations, this study suggests RS is safe regarding cancer induction. Synovitis is a known burden for patients. The decision of making reasonable usage of RS should be outweighed with the risks of leaving synovitis untreated.

Effectiveness of radiation synovectomy with samarium-153 particulate hydroxyapatite in rheumatoid arthritis patients with knee synovitis: a controlled randomized double-blind trial.

OBJECTIVES: The aim of the present study was to investigate the effectiveness of Samarium(153)-particulate hydroxyapatite radiation synovectomy in rheumatoid arthritis patients with chronic knee synovitis. METHODS: Fifty-eight rheumatoid arthritis patients (60 knees) with chronic knee synovitis participated in a controlled double-blinded trial. Patients were randomized to receive either an intra-articular injection with 40 mg triamcinolone hexacetonide alone (TH group) or 40 mg triamcinolone hexacetonide combined with 15 mCi Samarium(153)-particulate hydroxyapatite (Sm/TH group). Blinded examination at baseline (T0) and at 1 (T1), 4 (T4), 12 (T12), 32 (T32), and 48 (T48) weeks post-intervention were performed on all patients and included a visual analog scale for joint pain and swelling as well as data on morning stiffness, flexion, extension, knee circumference, Likert scale of improvement, percentage of improvement, SF-36 generic quality of life questionnaire, Stanford Health Assessment Questionnaire (HAQ), Lequesne index, use of non-steroidal anti-inflammatory drugs or oral corticosteroids, events and adverse effects, calls to the physician, and hospital visits. RESULTS: The sample was homogeneous at baseline, and there were no withdrawals. Improvement was observed in both groups in relation to T0, but no statistically significant differences between groups were observed regarding all variables at the time points studied. The Sm/TH group exhibited more adverse effects at T1 (p<0.05), but these were mild and transitory. No severe adverse effects were reported during follow-up. CONCLUSION: Intra-articular injection of Samarium(153)-particulate hydroxyapatite (15 mCi) with 40 mg of triamcinolone hexacetonide is not superior to triamcinolone hexacetonide alone for the treatment of knee synovitis in patients with rheumatoid arthritis at 1 y of follow-up.

Radiation safety considerations for the bone seeking radiopharmaceuticals. 89SrCl2, 186Re-HEDP and 153Sm-EDTMP.

UNLABELLED: The radiation exposure to bystanders from 89SrCl2, 186Re-HEDP and 153Sm-EDTMP, is generally thought to be caused by "bremsstrahlung" and gamma-radiation, with negligible contribution from beta-radiation. The latter assumption may be erroneous. The aim of this prospective study was the investigation of radiation safety after treatment with these radiopharmaceuticals. The radiation field around treated patients was characterized and the magnitude estimated. PATIENTS, METHODS: 33 patients (30 prostate carcinoma, 3 breast carcinoma) were treated with 150 MBq 89SrCl2 (9 patients), 1295 MBq 186Re-HEDP (12 patients) or 37 MBq/kg 153Sm-EDTMP (12 patients). External exposure rates at 30 cm from the patient were measured at times 0 to 72 h post-injection. To evaluate the respective contribution of Bremsstrahlung, beta- and gamma-radiation, a calibrated survey meter was used, equipped with a shutter. For each patient, the measured exposure rate-versus-time data were fit to a curve and the curve integrated (area under the curve) to estimate the total exposure. RESULTS: For 29/33 patients the total ambient equivalent doses (mean+/-1 standard deviation [SD]) based on the integral of the fitted curve were 2.1+/-1.2 mSv for 89SrCl2, 3.3+/-0.6 mSv for 186Re-HEDP and 2.8+/-0.6 mSv for 153Sm-EDTMP. Beta-radiation contributes significantly to these doses (>99% for 89SrCl2, 87% for 186Re-HEDP and 27% for 153Sm-EDTMP). The effective doses (at 30 cm) are <0.1 mSv for 89SrCl2, 0.3 mSv for 186Re-HEDP and 1.6 mSv for 153Sm-EDTMP. CONCLUSION: Patients treated with 89SrCl2, 186Re-HEDP or 153Sm-EDTMP emit a spectrum of radiation, including non-negligible beta-radiation. With specific instructions effective doses to bystanders are acceptable.

Effectiveness of radiation synovectomy with samarium-153 particulate hydroxyapatite in rheumatoid arthritis patients with knee synovitis: a controlled randomized double-blind trial

OBJECTIVES: The aim of the present study was to investigate the effectiveness of Samarium153-particulate hydroxyapatite radiation synovectomy in rheumatoid arthritis patients with chronic knee synovitis. METHODS: Fifty-eight rheumatoid arthritis patients (60 knees) with chronic knee synovitis participated in a controlled double-blinded trial. Patients were randomized to receive either an intra-articular injection with 40 mg triamcinolone hexacetonide alone (TH group) or 40 mg triamcinolone hexacetonide combined with 15 mCi Samarium153-particulate hydroxyapatite (Sm/TH group). Blinded examination at baseline (T0) and at 1 (T1), 4 (T4), 12 (T12), 32 (T32), and 48 (T48) weeks post-intervention were performed on all patients and included a visual analog scale for joint pain and swelling as well as data on morning stiffness, flexion, extension, knee circumference, Likert scale of improvement, percentage of improvement, SF-36 generic quality of life questionnaire, Stanford Health Assessment Questionnaire (HAQ), Lequesne index, use of non-steroidal anti-inflammatory drugs or oral corticosteroids, events and adverse effects, calls to the physician, and hospital visits. RESULTS: The sample was homogeneous at baseline, and there were no withdrawals. Improvement was observed in both groups in relation to T0, but no statistically significant differences between groups were observed regarding all variables at the time points studied. The Sm/TH group exhibited more adverse effects at T1 (p<0.05), but these were mild and transitory. No severe adverse effects were reported during follow-up. CONCLUSION: Intra-articular injection of Samarium153-particulate hydroxyapatite (15 mCi) with 40 mg of triamcinolone hexacetonide is not superior to triamcinolone hexacetonide alone for the treatment of knee synovitis in patients with rheumatoid arthritis at 1 y of follow-up.

Coating failure of commercial orthodontic magnets and DNA fragmentation of oral mucosa cells.

OBJECTIVE: To investigate possible adverse effects of orthodontic magnets on the oral mucosa. METHODS: Twenty orthodontic patients, between 14 and 20 years of age, were used. All patients consented to participate in the trial, which ran for six months. Following extraction of the first premolars, samarium-cobalt (SmCo5) orthodontic magnets were used to move the upper right canines into the extraction spaces. The contralateral canines were retracted with elastomeric chain. The orthodontic appliance consisted of direct-bonded standard edgewise fibreglass brackets and molar tubes, and teflon-coated preformed archwires. At regular scheduled visits the following were recorded: the condition of the protective magnet coating; weight loss by the magnets; levels of nickel, iron and chromium ions in unstimulated saliva; viability of recovered oral mucosa cells with trypan blue. DNA fragmentation of the oral mucosa cells was analysed at the start of the trial, after one week, one month, three months and six months with the single cell gel electrophoresis assay (Comet assay). The elemental compositions of five magnets were assessed with energy dispersive X-ray microanalysis. RESULTS: By the third month the magnets had lost their protective resin coats. At six months the magnets had lost 3 per cent of their initial weights. Significant weight loss and raised saliva levels of nickel, iron and chromium ions occurred from the first week. The number of oral mucosa cells with DNA fragmentation increased steadily on both sides of the mouth from the first week. More DNA fragmented cells occurred on the Magnet side than on the Non-magnet side. The trial was discontinued when half of the subjects showed DNA damaged mucosal cells. CONCLUSIONS: Because the protective coating failed after a few weeks, orthodontic magnets are unsuitable for long-term intra-oral use. It is uncertain if the greater cell damage on the Magnet side was due to the corrosion products, proximity to the static magnetic field or both factors.

Combined use of zoledronic acid and 153Sm-EDTMP in hormone-refractory prostate cancer patients with bone metastases.

PURPOSE: (153)Sm-ethylenediaminetetramethylenephosphonic acid (EDTMP; Quadramet) is indicated for the treatment of painful bone metastases, whereas zoledronic acid (Zometa) is indicated for the prevention of skeletal complications. Because of the different therapeutic effects, combining the treatments may be beneficial. Both, however, accumulate in areas with increased osteoblastic activity. Possible drug interactions were investigated. METHODS: Patients with hormone-refractory prostate cancer were treated with 18.5 MBq/kg (153)Sm-EDTMP in weeks 1 and 3 and with 37 MBq/kg in week 15. Treatment with 4 mg zoledronic acid began in week 3 and continued every 4 weeks through week 23. In weeks 3 and 15, zoledronic acid was administered 2 days before (153)Sm-EDTMP treatment. Urine was collected 48 h after injection of (153)Sm-EDTMP, and whole-body images were obtained 6, 24 and 48 h post-injection. The effect of zoledronic acid on total bone uptake of (153)Sm-EDTMP was measured indirectly by the cumulative activity excreted in the urine in weeks 1, 3 and 15. Biodistribution, safety, tolerability and effect on prostate-specific antigen level were also studied. RESULTS: The urinary excretion in week 3 divided by the urinary excretion in week 1 (baseline) times 100% was mean 98.4 +/- 11.6% (median 96.2%). From week 1 to 15, after four zoledronic acid treatments, the mean ratio was 101.9 +/- 10.7% (median 101.8%). Bioequivalence could be concluded by using a two-sample t test for both per-protocol (n = 13) and full-analysis sets (n = 18). Toxicity was comparable to of monotherapy with (153)Sm-EDTMP. CONCLUSION: Zoledronic acid treatment does not influence (153)Sm-EDTMP skeletal uptake. Combined treatment is feasible and safe.

Vascular radiolesion as a deleterious effect of high-dose-rate intraarterial brachytherapy with samarium-153 in hypercholesterolemic rabbits.

OBJECTIVE: This study was designed to evaluate vascular morphological and morphometric changes induced by brachytherapy with samarium-153 (Sm-153) at high doses in hypercholesterolemic rabbits. METHODS: Forty-three New Zealand White hypercholesterolemic rabbits were analyzed, and the total of 86 iliac arteries underwent balloon angioplasty injury. The rabbits were divided into three different groups: two irradiation groups (IG) assigned to 15 Gy (n=14) and 60 Gy (n=36) irradiation doses, respectively, and a control group (n = 36). Histomorphometric and qualitative histological analyses were performed for tissue evaluation. RESULTS: Significant reductions were found in neointimal proliferation (NIP) (p< 0.0001), media area (MA) (p<0.0001) and percent stenosis (p<0.0001) in the 15-Gy IG, compared to the other groups. The 60-Gy IG had the higher rate of NIP, increase in media and vessel areas (VA) and percent stenosis. The 60-Gy IG also showed the greatest number of xanthomatous cells (60-Gy IG: 86.11% and 15-Gy IG: 14.29%, p<0.0001) and the highest amount of hyaline amorphous tissue (60-Gy IG:58.33% and 15-Gy IG:0%, p=0.0001) and vascular proliferation (60-Gy IG:30.56% and 15-Gy IG:0%, p=0.0221). No statistically significant differences were found among groups concerning other tissue analyses. CONCLUSION: The high-dose irradiation of 60 Gy resulted in intense cell proliferation considered vascular radiolesion, unlike the 15-Gy dose, which was associated with an excellent inhibition of neointimal proliferation.

Radiolesão vascular como efeito deletério da braquiterapia intra-arterial com dose elevada de Samário-153 em coelhos hipercolesterolêmicos / Vascular radiolesion as a deleterious effect of high-dose-rate intraarterial brachytherapy with Samarium-153 in hypercholesterolemic rabbits / Vascular radiolesion as a deleterious effect of high-dose-rate intraarterial brachytherapy with Samarium-153 in hypercholesterolemic rabbits

OBJETIVO: Este estudo tem por objetivo avaliar as alterações vasculares morfológicas e morfométricas induzidas pela braquiterapia com Samário-153 (153 Sm) em coelhos hipercolesterolêmicos, com doses elevadas. MÉTODOS: Foram analisados 43 coelhos hipercolesterolêmicos, brancos, da raça New Zealand, e o total de 86 artérias ilíacas submetidas a lesão por balão de angioplastia. Divididos em três grupos: dois (GI) irradiados com as doses de 15Gy (n=14) e 60Gy (n=36) e um grupo controle (n=36). Foram realizadas avaliação histológica morfométrica e análise histológica qualitativa para análise tecidual. RESULTADOS: Foram observadas uma redução significativa da neoproliferação intimal (NPI) no GI 15 Gy (p<0,0001), uma redução da área de camada média (ACM) (p<0,0001) e por cento estenose (p<0,0001) comparada com os demais grupos. O GI 60 Gy teve o maior índice de PNI, aumento da ACM, AV e porcentagem de estenose. No GI 60 Gy, observou-se maior número de células xantomatosas (GI 60Gy:86,11 por cento e GI 15Gy:14,29 por cento, p<0,0001), tecido amorfo hialino (GI 60Gy:58,33 por cento e GI 15 Gy:0 por cento, p=0,0001) e proliferação vascular (GI60 Gy:30,56 por cento e GI15 Gy:0 por cento, p=0,0221). Outras análises teciduais não apresentaram diferença estatística entre os grupos. CONCLUSÃO: A dose elevada de 60Gy ocasionou intensa proliferação celular considerada radiolesão vascular, ao contrário da dose de 15Gy que apresentou excelente inibição da neo-proliferação intimal.

OBJECTIVE: This study was designed to evaluate vascular morphological and morphometric changes induced by brachytherapy with samarium-153 (Sm-153) at high doses in hypercholesterolemic rabbits. METHODS: Forty-three New Zealand White hypercholesterolemic rabbits were analyzed, and the total of 86 iliac arteries underwent balloon angioplasty injury. The rabbits were divided into three different groups: two irradiation groups (IG) assigned to 15 Gy (n=14) and 60 Gy (n=36) irradiation doses, respectively, and a control group (n = 36). Histomorphometric and qualitative histological analyses were performed for tissue evaluation. RESULTS: Significant reductions were found in neointimal proliferation (NIP) (p< 0.0001), media area (MA) (p<0.0001) and percent stenosis (p<0.0001) in the 15-Gy IG, compared to the other groups. The 60-Gy IG had the higher rate of NIP, increase in media and vessel areas (VA) and percent stenosis. The 60-Gy IG also showed the greatest number of xanthomatous cells (60-Gy IG: 86.11 percent and 15-Gy IG: 14.29 percent, p<0.0001) and the highest amount of hyaline amorphous tissue (60-Gy IG:58.33 percent and 15-Gy IG:0 percent, p=0.0001) and vascular proliferation (60-Gy IG:30.56 percent and 15-Gy IG:0 percent, p=0.0221). No statistically significant differences were found among groups concerning other tissue analyses. CONCLUSION: The high-dose irradiation of 60 Gy resulted in intense cell proliferation considered vascular radiolesion, unlike the 15-Gy dose, which was associated with an excellent inhibition of neointimal proliferation.

Samarium for osteoblastic bone metastases and osteosarcoma.

Samarium-153 lexidronam (153Sm-EDTMP) is FDA approved for painful osteoblastic bone metastases that image on bone scan. 153Sm-EDTMP decay has a therapeutic beta-emission and a gamma-photon for bone scan imaging. Monitoring of osteosarcoma radiation treatment effectiveness was performed with bone, CT, MRI and PET/CT fusion imaging. Bone scan and PET/CT improved in 5 out of 9 and 16 out of 18 osteosarcoma sites, respectively. 153Sm-EDTMP targets multiple sites of disease, with a single administration. Side effects of 153Sm-EDTMP (0.5-2.5 mCi/kg) have been minimal and include transient thrombocytopenia and neutropenia. 153Sm-EDTMP can be combined with radiation therapy, bisphosphonates and/or chemotherapy to synergistically improve palliation. This article reviews the rationale, indications and monitoring of standard-dose samarium and investigational high-dose 153Sm-EDTMP treatment of cancer involving bone.

Early-onset Guillain-Barré syndrome associated with reactivation of Epstein-Barr virus infection after nonmyeloablative stem cell transplantation.

We report a case of early-onset acute Guillain-Barre syndrome associated with reactivation of Epstein-Barr virus (EBV) infection after nonmyeloablative stem cell transplantation (NST). Reactivation of EBV infection preceded disease onset, and the virus load increased concomitantly with disease progression (doubling time, 2.7 days). This case raises concern about the expanding scope of manifestations associated with reactivation of EBV infection after NST.

Samarium-153-Lexidronam complex for treatment of painful bone metastases in hormone-refractory prostate cancer.

OBJECTIVES: A Phase III randomized trial was designed to assess the effectiveness of samarium-153 (153Sm)-lexidronam for palliation of bone pain in patients with hormone-refractory prostate cancer. METHODS: A total of 152 men with hormone-refractory prostate cancer and painful bone metastases were enrolled in a prospective, randomized, double-blind trial comparing radioactive (153Sm) versus nonradioactive (152Sm) lexidronam complexes. Patients were randomized (2:1) to the radioactive (153Sm) agent. Patient diaries recording daily pain and analgesic use were completed during a planned 16-week evaluation period. Nonresponders were informed of the treatment received after 4 weeks of treatment and, if initially treated with placebo, were allowed to receive 153Sm-lexidronam in an open-label fashion. Pain was measured using validated patient-derived visual analog scales and pain descriptor scales. RESULTS: 153Sm-lexidronam had positive effects on measures of pain relief compared with placebo within 1 to 2 weeks. Reductions in opioid use were recorded at weeks 3 and 4. Because nonresponders were unblinded at week 4, statistical comparisons between the arms beyond week 4 were not possible. Mild, transient bone marrow suppression was the only adverse event associated with 153Sm-lexidronam administration. The mean nadir white blood cell and platelet count (3 to 4 weeks after treatment) was 3800/microL and 127,000/microL, respectively. Counts recovered to baseline after approximately 8 weeks. No grade 4 decreases in either platelets or white bloods cells were documented. CONCLUSIONS: These findings demonstrate that 1 mCi/kg 153Sm-lexidronam is both safe and effective for the palliation of painful bone metastases in patients with hormone-refractory prostate cancer.

[Myelotoxicity after systemic radionuclide therapy of painful bone metastases with 153Samarium-EDTMP ]. / Myelotoxicita po systémové radionuklidové terapii bolestivých kostních metastáz 153Samariem-EDTMP.

AIM: The breast cancer and the prostate cancer are considered as the most frequently occurred metastatic tumors in bones. The bone pain appears in majority of patients with metastases. One possibility how to reduce or to remove this pain is the administration of the radiotherapy to the place of metastases. The present medicine disposes of two ways how to administer radiotherapy in the place of metastases: externally irradiation (loco-regional or half-body) or intravenous administration of bone-seeking therapeutic radiopharmaceuticals. MATERIAL AND METHOD: We introduced intravenous administration of 153Samarium-EDTMP in 57 patients (30 prostate cancer, 23 breast cancer, 4 renal cell carcinoma). Mean applied activity was 40 MBq per kg of patient's body weight. RESULTS: After 153Sm-EDTMP administration we observed pain relief of various degree in 75% of patients for three months. 1 and 3 months after 153Samarium-EDTMP administration the following haematologic parameters changes were seen: a) 7% reduction in red cell count in one month after administration, 15% reduction after three months. b) 43% reduction in leukocyte count in one month after administration, 24% reduction after three months. c) 50% reduction in platelet count in one month after administration, 23% reduction after three months. In all three haematological profiles (red cells, leukocytes, platelets) we detected reduction of values after treatment with 153Samarium-EDTMP. This reduction culminates one month after administration and in three months leukocytes and platelets count was getting better. CONCLUSION: Myelosuppression was mild and temporary. No patients had grade 4 hematological toxicity and only three patients (5%) had grade 3 hematological toxicity (National Cancer Institute Common Toxicity Criteria).

[Metabolic radiotherapy: what role will it have in 2001?]. / Radiothérapie métabolique: quel rôle en 2001?

Metabolic radiotherapy is a new therapy for management of bone pain in patients with bone metastatic prostate carcinoma. Strontium-89 and Samarium-153 concentrate in bone metastases and radiate them. A pain decrease is obtained in 60-70% of cases. Side effects are a significant hematological depression without great clinical consequences if good therapeutic indications are respected. Our multidisciplinary experience of these radionuclides in 54 performed treatments shows a rate of good responders of 66% with a rate of excellent results (total decrease of pain) in 47%. The therapeutic effectiveness is correlated with pain intensity measured by Visual Analogic Scale (VAS) and equivalent dose of morphine. Radionuclide therapy should be applied to patients as early as possible after establishment of bone metastases.

Cáncer de mama y 153 Samario EDTMP / Breast cancer and Samarium 153 EDTMP

Objetivo: evaluar la toxicidad y eficacia terapéutica del Sm153 EDTMP en pacientes con cáncer de mama avanzado y dolor producido por metástasis óseas con reacción osteoblástica y su repercusión centellográfica y de laboratorio. Materiales y métodos: 54 pacientes (edad promedio: 62) con metástasis óseas y dolor con Samario en dosis de 0,5; 1 y 1,5 mCi/kg; 5 pacientes fueron retratadas. Se realizó control clínico y laboratorio al inicio, semanalmente durante el primer mes y luego mensualmente. Se correlacionaron centellografías óseas pre y post tratamiento. De las 54 pacientes, 21 (primer grupo) recibieron 0,5 mCi/kg; 29 (segundo grupo) 1 mCi/kg y 4 pacientes (tercer grupo) 1,5 mCi/kg. Resultados: la respuesta positiva al tratamiento se valoró mediante la atenuación o desaparición del dolor y la disminución del uso de analgésicos. El primer grupo tuvo una respuesta positiva del 76 por ciento, el segundo de 83 por ciento y el tercero de 75 por ciento. La duración de la respuesta varió entre 3 y 9 meses. La toxicidad más frecuente fue trombocitopenia y luego leucopenia, ambas fueron reversibles y presentaban relación directa a la dosis administrada. La correlación centellográfica muestra una disminución de la intensidad de fijación en las pacientes retratadas. Conclusiones: el uso de radiofármacos con afinidad ósea como el Sm resulta ser una alternativa, dada su eficacia y accesibilidad de costos. En nuestro grupo de pacientes tratadas con una dosis de 1 mCi/kg se alcanzó una respuesta del 83 por ciento sin mayor aaumento de la toxicidad, la cual fue reversible (AU)

High-dose samarium-153 ethylene diamine tetramethylene phosphonate: low toxicity of skeletal irradiation in patients with osteosarcoma and bone metastases.

PURPOSE: Samarium-153 ethylene diamine tetramethylene phosphonate ((153)Sm-EDTMP), a bone-seeking radiopharmaceutical, provides therapeutic irradiation to osteoblastic bone metastases. Because the dose-limiting toxicity of (153)Sm-EDTMP is thrombocytopenia, a dose-escalation trial using peripheral-blood progenitor cells (PBPCs) or marrow support was conducted to treat metastatic bone cancer. PATIENTS AND METHODS: Patients with locally recurrent or metastatic osteosarcoma or skeletal metastases avid on bone scan were treated with 1, 3, 4.5, 6, 12, 19, or 30 mCi/kg of (153)Sm-EDTMP. RESULTS: Thirty patients were treated with (153)Sm-EDTMP. Transient symptoms of hypocalcemia were seen at 30 mCi/kg. Estimates of radioisotope bound to bone surfaces and marrow radiation dose were linear with injected amount of (153)Sm-EDTMP. Cytopenias also occurred in all subjects and were dose-related. At day +13 after (153)Sm-EDTMP, residual whole-body radioactivity was 1% to 65% of whole-body radioactivity considered safe for PBPC infusion, 3.6 mCi. After PBPC or marrow infusion on day +14 after (153)Sm-EDTMP, recovery of hematopoiesis was problematic in two patients at the 30 mCi/kg dose infused with less than 2 x 10(6) CD34(+)/kg on day +14, but not in other patients. Reduction or elimination of opiates for pain was seen in all patients. Patients had no adverse changes in appetite or performance status. CONCLUSION: (153)Sm-EDTMP with PBPC support can provide bone-specific therapeutic irradiation (estimates of 39 to 241 Gy). Hematologic toxicity at 30 mCi (153)Sm-EDTMP/kg requires PBPC grafts with more than 2 x 10(6) CD34(+)/kg to overcome myeloablative effects of skeletal irradiation. Nonhematologic side effects are minimal.

Samarium Sm-153 lexidronam for the palliation of bone pain associated with metastases.

BACKGROUND: In patients with bone pain due to metastatic disease, intravenous systemic radioisotope therapy may be a useful adjunct to other methods for palliating pain. METHODS: Various studies have been performed utilizing a short-lived radioisotope conjugated to a tetraphosphonate (samarium 153 lexidronam) both as an open label and as a double blinded, placebo-controlled study. Patients with varying tumor types including those of the prostate, breast, lung, and other sites were studied. Two dose levels were used (0.5 millicuries (mCi)/kg and 1.0 mCi/kg) with patients monitored for 16 weeks for efficacy (pain scores, opiod analgesic score, and quality of life) parameters and adverse events. RESULTS: All 3 studies showed that at the 1.0 mCi/kg dose level statistically significant improvement over placebo was observed by 4 weeks with relief of pain noted in many patients by 1 week. The only significant adverse event was transient myelosuppression with a nadir at 4-6 weeks and recovery by 8 weeks. Less than 10% of patients had National Cancer Institute Common Toxicity Criteria Grade III/IV bone marrow toxicity recorded. CONCLUSIONS: Systemic metabolic radiotherapy with samarium 153 lexidronam appears to be a safe and efficacious method for treating patients with bone pain. The shorter radioisotope half-life allows for a high dose rate to be delivered over a short period, which may have certain biologic benefits.

Dose response relationship and multiple dose efficacy and toxicity of samarium-153-EDTMP in metastatic cancer to bone.

INTRODUCTION: The optimal dose of samarium-153-EDTMP (153Sm-EDTMP) for effective palliation of painful metastases to bone is under investigation. It is not known whether increased doses of 153Sm EDTMP will lead to better and longer pain and tumour control and survival. Multiple dose efficacy and toxicity is of importance as most Patients will require prolonged support for pain. METHODS: Twenty-eight (28) patients were treated with 0.75 mCi/kg, 35 patients with 1.5 mCi/kg and 19 patients with 3 mCi/kg in three sequential Phase I-II trials. Multiple doses were given to patients on the 0.75 mCi/kg and 1.5 mCi/kg dose levels. RESULTS: At all dose levels adequate pain control was achieved in 78-95% of patients. The duration of pain control was 40-56 days with the best results in the 1.5 mCi/kg group (56 days). There is no evidence that increasing dose leads to better and longer pain control, tumour response and survival, but toxicity is increased. Multiple doses can be given with acceptable toxicity and pain control, however, only 38% of patients will qualify for multiple treatments. CONCLUSION: 153Sm-EDTMP provides adequate and safe palliation but multiple doses can only be given in 38% of patients. There is not a clear dose-response relationship. The length of pain control is satisfactory but not ideal and hospitalisation for 4 days every 6-8 weeks is a disadvantage. Further research is required to combine 153Sm-EDTMP with cytostatics and to administer it on an out patient basis.