Phase I/II clinical trial of high-dose [131I] meta-iodobenzylguanidine therapy for high-risk neuroblastoma preceding single myeloablative chemotherapy and haematopoietic stem cell transplantation

Effective Treatment of SSTR2-Positive Small Cell Lung Cancer Using 211At-Containing Targeted α-Particle Therapy Agent Which Promotes Endogenous Antitumor Immune Response

Small cell lung cancer (SCLC) is a neuroendocrine tumor with a high degree of malignancy. Due to limited treatment options, patients with SCLC have a poor prognosis. We have found, however, that intravenously administered octreotide (Oct) armed with astatine-211 ([211At]SAB-Oct) is effective against a somatostatin receptor 2 (SSTR2)-positive SCLC tumor in SCLC tumor-bearing BALB/c nude mice. In biodistribution analysis, [211At]SAB-Oct achieved the highest concentration in the SCLC tumors up to 3 h after injection as time proceeded. A single intravenous injection of [211At]SAB-Oct (370 kBq) was sufficient to suppress SSTR2-positive SCLC tumor growth in treated mice by inducing DNA double-strand breaks. Additionally, a multitreatment course (370 kBq followed by twice doses of 370 kBq for a total of 1110 kBq) inhibited the growth of the tumor compared to the untreated control group without significant off-target toxicity. Surprisingly, we found that [211At]SAB-Oct could up-regulate the expressions of calreticulin and major histocompatibility complex I (MHC-I) on the tumor cell membrane surface, suggesting that α-particle internal irradiation may activate an endogenous antitumor immune response through the regulation of immune cells in the tumor microenvironment, which could synergically enhance the efficacy of immunotherapy. We conclude that [211At]SAB-Oct is a potential new therapeutic option for SSTR2-positive SCLC.

Timing and chemotherapy association for 131-I-MIBG treatment in high-risk neuroblastoma

Prognosis of high-risk neuroblastoma is dismal, despite intensive induction chemotherapy, surgery, high-dose chemotherapy, radiotherapy, and maintenance. Patients who do not achieve a complete metastatic response, with clearance of bone marrow and skeletal NB infiltration, after induction have a significantly lowersurvival rate. Thus, it's necessary to further intensifytreatment during this phase. 131-I-metaiodobenzylguanidine (131-I-MIBG) is a radioactive compound highly effective against neuroblastoma, with32% response rate in relapsed/resistant cases, and only hematological toxicity. 131-I-MIBG wasutilized at different doses in single or multiple administrations, before autologous transplant or combinedwith high-dose chemotherapy. Subsequently, it was added to consolidationin patients with advanced NB after induction, but an independent contribution against neuroblastoma and for myelotoxicity is difficult to determine. Despiteresults of a 2008 paper demonstratedefficacy and mild hematological toxicity of 131-I-MIBG at diagnosis, no center had included it with intensive chemotherapy in first-line treatment protocols. In our institution, at diagnosis, 131-I-MIBG was included in a 5-chemotherapy drug combination and administered on day-10, at doses up to 18.3 mCi/kg. Almost 87% of objective responses were observed 50 days from start with acceptable hematological toxicity. In this paper, we review the literature data regarding 131-I-MIBG treatment for neuroblastoma, and report on doses and combinations used, tumor responses and toxicity. 131-I-MIBG is very effective against neuroblastoma, in particular if given to patients at diagnosis and in combination with chemotherapy, and it should be included in all induction regimens to improve early responses rates and consequently long-term survival.

Adrenal functional imaging - which marker for which indication?

PURPOSE OF REVIEW

In recent years, a broad spectrum of molecular image biomarkers for assessment of adrenal functional imaging have penetrated the clinical arena. Those include positron emission tomography and single photon emission computed tomography radiotracers, which either target glucose transporter, CYP11B enzymes, C-X-C motif chemokine receptor 4, norepinephrine transporter or somatostatin receptors. We will provide an overview of key radiopharmaceuticals and determine their most relevant clinical applications, thereby providing a roadmap for the right image biomarker at the right time for the right patient.

RECENT FINDINGS

Numerous radiotracers for assessment of adrenal incidentalomas ([18F]FDG; [123I]IMTO/IMAZA), ACC ([123I]IMTO/IMAZA; [18F]FDG; [68Ga]PentixaFor), pheochromocytomas and paragangliomas ([123I]mIBG; [18F]flubrobenguane; [18F]AF78; [68Ga]DOTATOC/-TATE), or primary aldosteronism ([11C]MTO, [68Ga]PentixaFor) are currently available and have been extensively investigated in recent years. In addition, the field is currently evolving from adrenal functional imaging to a patient-centered adrenal theranostics approach, as some of those radiotracers can also be labeled with ß-emitters for therapeutic purposes.

SUMMARY

The herein reviewed functional image biomarkers may not only allow to increase diagnostic accuracy for adrenal gland diseases but may also enable for achieving substantial antitumor effects in patients with adrenocortical carcinoma, pheochromocytoma or paraganglioma.