Improving Overall Survival and Quality of Life in Patients with Prostate Cancer and Neuroendocrine Tumors Using 177Lu-iPSMA and 177Lu-DOTATOC: Experience after 905 Treatment Doses.

177Lu-iPSMA is a novel radioligand developed at ININ-Mexico with a high affinity for the PSMA protein heavily expressed in cancer cells of approximately 95% of patients with metastatic castration-resistant prostate cancer (mCRPC). 177Lu-DOTATOC is a patent-free radioligand, molecularly recognized by somatostatin receptors (SSTR-2) overexpressed in cancer cells of about 80% of patients with metastatic gastroenteropancreatic neuroendocrine tumors (GEP-NET). This translational research aimed to determine the efficacy and safety of 177Lu-iPSMA and 177Lu-DOTATOC developed as GMP pharmaceutical formulations for treating progressive and advanced mCRPC and NET. One hundred and forty-five patients with mCRPC and one hundred and eighty-seven subjects with progressive NET (83% GEP-NET and 17% other NET), treated with 177Lu-iPSMA and 177Lu-DOTATOC, respectively, were evaluated. Patients received a mean dose of 7.4 GBq per administration of 177Lu-iPSMA (range 1-5 administrations; 394 treatment doses) or 177Lu-DOTATOC (range 2-8 administrations; 511 treatment doses) at intervals of 1.5-2.5 months. Efficacy was assessed by SPECT/CT or PET/CT. Results were stratified by primary tumor origin and number of doses administered. Patients with mCRPC showed overall survival (OS) of 21.7 months with decreased radiotracer tumor uptake (SUV) and PSA level in 80% and 73% of patients, respectively. In addition, a significant reduction in pain (numerical scale from 10-7 to 3-1) was observed in 88% of patients with bone metastases between one and two weeks after the second injection. In the GEP-NET population, the median progression-free survival was 34.7 months, with an OS of >44.2 months. The treatments were well tolerated. Only ten patients experienced grade ≥ 3 myelosuppression (3% of all patients). The observed safety profiles and favorable therapeutic responses demonstrated the potential of 177Lu-iPSMA and 177Lu-DOTATOC to improve overall survival and quality of life in patients with progressive and advanced mCRPC and NET.

Effectiveness of radiolabelled somatostatin analogues (90Y-DOTATOC and 177Lu-DOTATATE) in patients with metastatic neuroendocrine tumours: a single centre experience in Mexico. / Eficacia de los análogos de somatostatina radiomarcados (90Y-DOTATOC y 177Lu-DOTATATE) en pacientes con tumores neuroendocrinos metastásicos, experiencia de centro único en México.

OBJECTIVE: To determine the effectiveness of therapy with the radiolabelled somatostatin analogues, 90Y-DOTATOC and 177Lu-DOTATATE, in the treatment of metastatic neuroendocrine tumours with progression to first-line treatment. MATERIAL AND METHODS: A study was conducted on 30 patients diagnosed with neuroendocrine tumours (gastroenteropancreatic, bronchopulmonary, MEN2A, MEN2B, phaeochromocytoma, and paraganglioma) with metastatic disease diagnosed by the pathology department, with progression to first-line treatment, and recruited from December 2014 to February 2016. Efficacy was analysed using computed tomography (CT) according RECIST 1.1 criteria, and the molecular changes using the SUVmax of PET/CT with 68Ga-DOTATOC. Safety was carried out with a renal scan with 99mTc-MAG3. RESULTS: The 30 patients received a total of 49 cycles 90Y-DOTATOC (21 doses) and 177 Lu-DOTATATE (28 doses), with a mean of 1.5 cycles per patient. Of these, 17 (56.7%) showed a partial morphological response, 22 (73.3%) molecular and biochemical response, and 23 (76.6%) clinical response. One patient died during the median follow-up of 13 months. The median overall survival from diagnosis was 54 months (95% CI; 31.18-76.81), and median progression-free survival was 32 months (95% CI; 15.00-48.99). CONCLUSION: Therapy with 90Y-DOTATOC and 177Lu-DOTATATE is a promising therapy for patients with well and moderately differentiated neuroendocrine tumours. The efficacy is better the larger the number of cycles administered, inversely proportional to the number of metastases (<10), and is associated with the level of uptake according to the SUVmax by the metastases, regardless of metabolically active tumour volume.

Diagnostic work-up of gastroenteropancreatic neuroendocrine tumors

Neuroendocrine tumors are a heterogeneous group of malignancies that present a diagnostic challenge. The majority of patients (more than 60%) present with metastatic disease at diagnosis. The diagnosis is based on histopathology, imaging, and circulating biomarkers. The histopathology should contain specific neuroendocrine markers such as chromogranin A, synaptophysin, and neuron-specific enolase and also an estimate of the proliferation by Ki-67 (MIB1). Standard imaging procedures consist of computed tomography or magnetic resonance imaging together with somatostatin receptor scintigraphy. 68Ga-DOTA-octreotate scans will in the future replace somatostatin receptor scintigraphy because they have higher specificity and sensitivity. Other positron imaging tomographic scanning tracers that will come into clinical use are 18F-DOPA and 11C-5HTP. Neuroendocrine tumors secrete many different peptides and amines that can be used as circulating biomarkers. The most useful general marker is chromogranin A, which is both a diagnostic and prognostic marker in most neuroendocrine tumors. However, there is still a need for improved biomarkers for early detection and follow-up of patients during treatment. In addition, molecular imaging can be further developed for both detection and evaluation of treatment.

Tratamiento de tumores neuroendocrinos (TNE) con péptidos análogos de la somatostatina marcados con radionucleidos / Treatment of neuroendocrine tumors (NET) with radiolabelled somatostatin analogues

Propósito. Los TNE avanzados tienen escasa respuesta a radioterapia o quimioterapia, el tratamiento sistémico con análogos de la SST radiactivos es una herramienta promisoria en su tratamiento. Presentamos nuestra experiencia, pionera en Latinoamérica, utilizando análogos de SST marcados con 90Y ó 177Lu. Material. Evaluamos 40 pacientes (50.3 años, rango 12-74) con TNE confirmados histológicamente y sobre-expresión de receptores de SST demostrada mediante imágenes. SPECT (111In-DOTATOC) ó PET/CT (68Ga-DOTATATE). Se evaluó respuesta clínica, laboratorio, imágenes con 111In-DOTATATE, post-terapia con 90Y ó 177Lu, 68Ga-DOTATATE PET/CT o TAC. Resultados. Observamos progresión de enfermedad en 10 (25.0 por ciento), remisión parcial en 25 (62.5 por ciento), enfermedad estable en 3 (7.5 por ciento) y remisión completa en 2 (5.0 por ciento). Hubo escasa toxicidad sin deterioro renal significativo. Observamos reducción tumoral y mejoría de calidad de vida en la mayoría de los pacientes. Conclusión. La terapia con radiopéptidos es un procedimento seguro y efectivo en el tratamiento de TNE avanzados.

Purpose. Advanced NETs have little response to radiotherapy or chemotherapy, systemic treatment with radioactive SST analogous is a promissory tool in its treatment. We present our pioneering experience in Latin America using analogous of SST labeled either with 90Y or 177Lu. Materials. We evaluated 40 patients (50.3 years, range 12-74) with histological proved NET and SST receptors over-expression demonstrated by SPECT or PET/CT images with 111In-DOTATOC or 68Ga-DOTATATE. We evaluated clinical response, laboratory test, images with 111In-DOTATATE, 90Y, 177Lu, and 68Ga-DOTATATE PET/CT or CT. Results. We observed progression of disease in 10 (7,5 percent), partial remission in 25 (62,5 percent), stable disease in 3 (7,5 percent) and complete remission in 2 (5,0 percent). There was little toxicity without significant renal deterioration. We observed tumor mass reduction and improvement of quality of life in most of the patients. Conclusion. The therapy with radiopeptides is a safe and effective procedure in the treatment of advanced NET.