German Multicenter Study Investigating 177Lu-PSMA-617 Radioligand Therapy in Advanced Prostate Cancer Patients

¹⁷⁷Lu-labeled PSMA-617 is a promising new therapeutic agent for radioligand therapy (RLT) of patients with metastatic castration-resistant prostate cancer (mCRPC). Initiated by the German Society of Nuclear Medicine, a retrospective multicenter data analysis was started in 2015 to evaluate efficacy and safety of ¹⁷⁷Lu-PSMA-617 in a large cohort of patients.

METHODS

One hundred forty-five patients (median age, 73 y; range, 43-88 y) with mCRPC were treated with ¹⁷⁷Lu-PSMA-617 in 12 therapy centers between February 2014 and July 2015 with 1-4 therapy cycles and an activity range of 2-8 GBq per cycle. Toxicity was categorized by the common toxicity criteria for adverse events (version 4.0) on the basis of serial blood tests and the attending physician's report. The primary endpoint for efficacy was biochemical response as defined by a prostate-specific antigen decline ≥ 50% from baseline to at least 2 wk after the start of RLT.

RESULTS

A total of 248 therapy cycles were performed in 145 patients. Data for biochemical response in 99 patients as well as data for physician-reported and laboratory-based toxicity in 145 and 121 patients, respectively, were available. The median follow-up was 16 wk (range, 2-30 wk). Nineteen patients died during the observation period. Grade 3-4 hematotoxicity occurred in 18 patients: 10%, 4%, and 3% of the patients experienced anemia, thrombocytopenia, and leukopenia, respectively. Xerostomia occurred in 8%. The overall biochemical response rate was 45% after all therapy cycles, whereas 40% of patients already responded after a single cycle. Elevated alkaline phosphatase and the presence of visceral metastases were negative predictors and the total number of therapy cycles positive predictors of biochemical response.

CONCLUSION

The present retrospective multicenter study of ¹⁷⁷Lu-PSMA-617 RLT demonstrates favorable safety and high efficacy exceeding those of other third-line systemic therapies in mCRPC patients. Future phase II/III studies are warranted to elucidate the survival benefit of this new therapy in patients with mCRPC.

Survival after yttrium-90 resin microsphere radioembolization of hepatocellular carcinoma across Barcelona clinic liver cancer stages: a European evaluation

A multicenter analysis was conducted to evaluate the main prognostic factors driving survival after radioembolization using yttrium-90-labeled resin microspheres in patients with hepatocellular carcinoma at eight European centers. In total, 325 patients received a median activity of 1.6 GBq between September 2003 and December 2009, predominantly as whole-liver (45.2%) or right-lobe (38.5%) infusions. Typically, patients were Child-Pugh class A (82.5%), had underlying cirrhosis (78.5%), and had good Eastern Cooperative Oncology Group (ECOG) performance status (ECOG 0-1; 87.7%), but many had multinodular disease (75.9%) invading both lobes (53.1%) and/or portal vein occlusion (13.5% branch; 9.8% main). Over half had advanced Barcelona Clinic Liver Cancer (BCLC) staging (BCLC C, 56.3%) and one-quarter had intermediate staging (BCLC B, 26.8%). The median overall survival was 12.8 months (95% confidence interval, 10.9-15.7), which varied significantly by disease stage (BCLC A, 24.4 months [95% CI, 18.6-38.1 months]; BCLC B, 16.9 months [95% CI, 12.8-22.8 months]; BCLC C, 10.0 months [95% CI, 7.7-10.9 months]). Consistent with this finding , survival varied significantly by ECOG status, hepatic function (Child-Pugh class, ascites, and baseline total bilirubin), tumor burden (number of nodules, alpha-fetoprotein), and presence of extrahepatic disease. When considered within the framework of BCLC staging, variables reflecting tumor burden and liver function provided additional prognostic information. The most significant independent prognostic factors for survival upon multivariate analysis were ECOG status, tumor burden (nodules >5), international normalized ratio >1.2, and extrahepatic disease. Common adverse events were: fatigue, nausea/vomiting, and abdominal pain. Grade 3 or higher increases in bilirubin were reported in 5.8% of patients. All-cause mortality was 0.6% and 6.8% at 30 and 90 days, respectively.

CONCLUSION

This analysis provides robust evidence of the survival achieved with radioembolization, including those with advanced disease and few treatment options.

Early side effects and first results of radioligand therapy with (177)Lu-DKFZ-617 PSMA of castrate-resistant metastatic prostate cancer: a two-centre study

Background

Radioligand therapy (RLT) with ¹⁷⁷Lu-DKFZ-617 PSMA (Lu-PSMA) (prostate-specific membrane antigen) is a novel targeted therapy of metastatic prostate cancer. We analysed retrospectively the early side effects and the response rate in the first patients, who received a therapy with Lu-PSMA in our departments.

Methods

RLT was performed in ten hormone- and/or chemo-refractory patients with distant metastases and progressive disease (mean age 73.5 years). ⁶⁸Ga-PSMA HBED-CC PET/CT was performed in all patients prior to RLT. The median PSA level prior to the therapy was 298.5 ng/ml (range 5–853 ng/ml). All patients received CBC, renal and liver function tests the day before and 2 days after application (mean administered activity 5.6 GBq, range 4.1–6.1 GBq), followed by further tests every 2 weeks. All patients were contacted by telephone every week regarding side effects or any positive and negative changes.

Results

Eight weeks after the therapy, seven patients (70 %) experienced a PSA decline, of whom six experienced more than 30 % and five more than 50 %. Three patients showed a progressive disease according to the PSA increase. No patient experienced any side effects immediately after injection of Lu-PSMA. Relevant hematotoxicity (grade 3 or 4) occurred 7 weeks after the administration in just one patient. The same patient showed a leucopenia grade 2. Two patients showed a disturbance of only 1 hematologic cell line, whereas one patient showed a reduction of grades 1 and 2 in leucocytes and thrombocytes, respectively. Six patients did not show any hematotoxicity during the 8 weeks after therapy. There was no relevant nephrotoxicity (grade 3 or 4).

Conclusions

Our initial results indicate that RLT with Lu-PSMA is safe and seems to have low early side-effect profile. A relevant PSA decline was detected in 70 % of patients.

Therapeutic response and side effects of repeated radioligand therapy with 177Lu-PSMA-DKFZ-617 of castrate-resistant metastatic prostate cancer

Prostate-specific membrane antigen (PSMA) is highly expressed on prostate epithelial cells and strongly up-regulated in prostate cancer (PC), making it an optimal target for the treatment of metastasized PC. Radioligand therapy (RLT) with ¹⁷⁷Lu-PSMA-DKFZ-617 (Lu-PSMA) is a targeted therapy for metastatic PC. In this study, we retrospectively analyzed the side effects and the response rate of 24 hormone and/or chemorefractory PC patients with a mean age of 75.2 years (range: 64–82) with distant metastases and progressive disease according to the PSA level, who were treated with Lu-PSMA. Median PSA was 522 ng/ml (range: 17–2360). Forty-six cycles of Lu-PSMA were performed. Of the 24 patients, 22 received two cycles. Eight weeks after the first cycle of Lu-PSMA therapy 79.1% experienced a decline in PSA level. Eight weeks after the second cycle of Lu-PSMA therapy 68.2% experienced a decline in PSA relative to the baseline value. Apart from two cases of grade 3 anemia, there was no relevant hemato- or nephrotoxicity (grade 3 or 4). These results confirmed that Lu-PSMA is a safe treatment option for metastatic PC patients and has a low toxicity profile. A positive response to therapy in terms of decline in PSA occurs in about 70% of patients.

Theranostics in nuclear medicine practice

The importance of personalized medicine has been growing, mainly due to a more urgent need to avoid unnecessary and expensive treatments. In nuclear medicine, the theranostic approach is an established tool for specific molecular targeting, both for diagnostics and therapy. The visualization of potential targets can help predict if a patient will benefit from a particular treatment. Thanks to the quick development of radiopharmaceuticals and diagnostic techniques, the use of theranostic agents has been continually increasing. In this article, important milestones of nuclear therapies and diagnostics in the context of theranostics are highlighted. It begins with a well-known radioiodine therapy in patients with thyroid cancer and then progresses through various approaches for the treatment of advanced cancer with targeted therapies. The aim of this review was to provide a summary of background knowledge and current applications, and to identify the advantages of targeted therapies and imaging in nuclear medicine practices.

Radioembolization of liver tumors with yttrium-90 microspheres

Radioembolization (RE), also termed selective internal radiation therapy (SIRT), has been gradually introduced to the clinical arsenal of cytoreductive modalities in recent years. There is growing evidence for efficiency in liver tumors of various entities, with the most prominent ones being hepatocellular carcinoma, colorectal cancer, and neuroendocrine tumors. Hepatic metastases of numerous other tumor entities including breast cancer, cholangiocarcinoma, and pancreatic cancer are treatment-sensitive, even when being refractory to other treatment modalities such as bland-embolization, regional, or systemic chemotherapy. The antitumor effect of SIRT is related to radiation rather than embolization, with extraordinary high local radiation doses obtained selectively at the site of viable tumor and little affection of the surrounding normal liver tissue. Morphologic changes after RE may pose difficulties for interpretation in conventional restaging with regard to tumor viability and true response to treatment. Therefore, functional imaging, that is, metabolic imaging with (18)F fluorodeoxyglucose positron emission tomography (computed tomography) in the majority of treated tumors, is regarded the gold standard in this respect and should be included for pre- and post-SIRT assessment. To prevent serious toxicity to be associated with the potent antitumor efficacy, meticulous pretreatment evaluation is of particular importance. Improvements in predicting dosimetry will help optimize treatment and patient selection. Nuclear medicine procedures are essential for planning, performing, and monitoring of RE. However, the interdisciplinary aspect of patient management has to be emphasized for this particular treatment form. As SIRT is moving forward from the salvage setting indication to the use in earlier stages of hepatic tumor disease and with the advent of new treatment protocols and targeted therapies, embedding SIRT into a multidisciplinary approach will become even more important. This article focuses on procedural and technical aspects for selection, preparation, and performance of treatment as well as post-therapeutic monitoring and response assessment.

PSMA Theranostics: Current Status and Future Directions

Prostate-specific membrane antigen (PSMA) is a promising target for imaging diagnostics and targeted radionuclide therapy (theranostics) of prostate cancer and its metastases. There is increasing evidence of encouraging response rates and a low toxicity profile of radioligand therapy (RLT) of metastatic castration-resistant prostate cancer using ¹⁷⁷Lu-labeled PSMA ligands. In this article, we review the current status of diagnostics and therapy using radiolabeled PSMA ligands. We also suggest protocols for patient selection criteria and conduct of PSMA-based RLT. Challenges and opportunities of PSMA theranostics are discussed.

Overall survival and response pattern of castration-resistant metastatic prostate cancer to multiple cycles of radioligand therapy using [177Lu]Lu-PSMA-617

PURPOSE

Up to 30% of patients with castration-resistant prostate cancer (CRPC) do not show any response to the first cycle of radioligand therapy (RLT) with [¹⁷⁷Lu]Lu-PSMA-617 (Lu-PSMA). We evaluated patient response to the second and third cycles of RLT in patients that underwent at least three cycles. The second aim of this study was to calculate the median overall survival (OS) of responders and non-responders after the first cycle and after all three cycles of RLT.

METHODS

CRPC patients were treated with Lu-PSMA, with a median interval of 8 weeks between each cycle. The tumour marker prostate-specific antigen (PSA) was used as the marker for response evaluation.

RESULTS

Fifty-two patients underwent a total of 190 cycles of RLT (3-6 cycles per patient). Of these, 80.8% showed a decline in PSA 2 months after the first cycle, with 44.2% showing a PSA decline of ≥50%. When compared to baseline PSA, 73.1% showed a PSA decline after the third cycle. 50% of patients that did not show any response to the first cycle also did not respond to the second and third cycles. The median OS was 60 weeks in all patients. The median OS was significantly longer for patients that showed any PSA decline after the first cycle compared to patients without PSA decline (68 vs. 33 weeks). There was a significant difference in median OS between responders and non-responders for a change in PSA after the third cycle compared to baseline PSA.

CONCLUSION

Patients with a positive response to RLT, regardless of the rate of decline, had a significantly longer median OS. Of the patients that did not show any response to the first cycle, 50% responded to the second or third cycles.

Peptide receptor radionuclide therapy in gastroenteropancreatic NEN G3: a multicenter cohort study

Peptide receptor radionuclide therapy (PRRT) is an established treatment of metastatic neuroendocrine tumors grade 1-2 (G1-G2). However, its possible benefit in high-grade gastroenteropancreatic (GEP) neuroendocrine neoplasms (NEN G3) is largely unknown. We therefore aimed to assess the benefits and side effects of PRRT in patients with GEP NEN G3. We performed a retrospective cohort study at 12 centers to assess the efficacy and toxicity of PRRT in patients with GEP NEN G3. Outcomes were response rate, disease control rate, progression-free survival (PFS), overall survival (OS) and toxicity. We included 149 patients (primary tumor: pancreatic n = 89, gastrointestinal n = 34, unknown n = 26). PRRT was first-line (n = 30), second-line (n = 62) or later-line treatment (n = 57). Of 114 patients evaluated, 1% had complete response, 41% partial response, 38% stable disease and 20% progressive disease. Of 104 patients with documented progressive disease before PRRT, disease control rate was 69%. The total cohort had median PFS of 14 months and OS of 29 months. Ki-67 21-54% (n = 125) vs Ki-67 ≥55% (n = 23): PFS 16 vs 6 months (P < 0.001) and OS 31 vs 9 months (P < 0.001). Well (n = 60) vs poorly differentiated NEN (n = 62): PFS 19 vs 8 months (P < 0.001) and OS 44 vs 19 months (P < 0.001). Grade 3-4 hematological or renal toxicity occurred in 17% of patients. This large multicenter cohort of patients with GEP NEN G3 treated with PRRT demonstrates promising response rates, disease control rates, PFS and OS as well as toxicity in patients with mainly progressive disease. Based on these results, PRRT may be considered for patients with GEP NEN G3.

Predictors of Response to Radioligand Therapy of Metastatic Castrate-Resistant Prostate Cancer with 177Lu-PSMA-617

Radioligand therapy (RLT) with ¹⁷⁷Lu-PSMA-617 (PSMA is prostate-specific membrane antigen) is a novel targeted therapy for metastatic prostate cancer. In this study, we evaluated the effect of different pretherapeutic parameters on the therapeutic response measured by prostate-specific antigen (PSA) 2 mo after RLT.

METHODS

RLT was performed in 40 hormone-refractory patients with distant metastases and progressive disease (mean age, 71.4 y). ⁶⁸Ga-PSMA-11 PET/CT was performed in all patients 1-2 wk before RLT. All patients were treated with a mean of 6 GBq. The SUV_max of tumor lesions was determined using region-of-interest analysis. Complete blood counts, renal and liver function assessments, previous therapies, pain medication, and SUVs were included in the analysis. PSA was assessed 2 mo after RLT.

RESULTS

In the univariate analysis, younger age, higher levels of γ-glutamyl transferase, lower pretherapeutic hemoglobin, a higher Gleason score, a higher number of platelets, higher C-reactive protein, regular need for pain medication, and higher lactate dehydrogenase had a negative impact on the therapeutic response; however, the multivariate analysis revealed that the most significant independent factors were the number of platelets and regular need for pain medication. The response was independent of the amount of PSMA uptake as well as previous therapies and other measured factors.

CONCLUSION

A PSA decline of more than 50% was observed significantly more in patients without a regular need for analgesics.

The impact of repeated cycles of radioligand therapy using [177Lu]Lu-PSMA-617 on renal function in patients with hormone refractory metastatic prostate cancer

BACKGROUND

[¹⁷⁷Lu]Lu-PSMA-617 is a well-tolerated therapy for the treatment of metastatic prostate cancer. However, because of the mainly renal excretion of the tracer, the kidneys are one of the most limiting organs. The purpose of this study was to examine the post-therapeutic changes in renal function over time and to identify risk factors for developing renal toxicity. We also tested the reliability of markers for renal function monitoring.

METHODS

Fifty-five patients with castrate-resistant metastatic prostate cancer treated with at least three cycles of [¹⁷⁷Lu]Lu-PSMA-617 were investigated. Renal function was assessed through laboratory tests (creatinine, GFR, cystatin C) and Tc-99 m-MAG3 measurements. Adverse events were classified according to the Common Terminology Criteria for Adverse Events (CTCAE) v4.0. To identify risk factors for renal toxicity, we used Pearson's correlation coefficient and the corresponding p values.

RESULTS

None of the 55 patients experienced severe nephrotoxicity (grade 3/4). In 14 patients (25%), we observed increased creatinine levels of CTC 1° or 2°. There were 16 cases of increased GFR (grade 1/2). At the baseline, only 14 patients had elevated cystatin C. However, post-therapeutic cystatin C was elevated in 32 patients (58%). A significant effect on renal function was found for age (p = 0.049), hypertension (p = 0.001) and pre-existing kidney disease (p = 0.001). The most reliable predictive markers of nephrotoxicity were TER-MAG3 and cystatin C.

CONCLUSION

Renal toxicity in patients treated with [¹⁷⁷Lu]Lu-PSMA-617 was low. There was no (sub)acute grade 3 or 4 nephrotoxicity.

The significance of 99mTc-MAA SPECT/CT liver perfusion imaging in treatment planning for 90Y-microsphere selective internal radiation treatment

Selective internal radiation therapy (SIRT), a catheter-based liver-directed modality for treating primary and metastatic liver cancer, requires appropriate planning to maximize its therapeutic response and minimize its side effects. (99m)Tc-macroaggregated albumin (MAA) scanning should precede the therapy to detect any extrahepatic shunting to the lung or gastrointestinal tract. Our aim was to compare the ability of SPECT/CT with that of planar imaging and SPECT in the detection and localization of extrahepatic (99m)Tc-MAA accumulation and to evaluate the impact of SPECT/CT on SIRT treatment planning and its added value to angiography in this setting.

METHODS

Ninety diagnostic hepatic angiograms with (99m)Tc-MAA were obtained for 76 patients with different types of cancer. All images were reviewed retrospectively for extrahepatic MAA deposition in the following order: planar, non-attenuation-corrected SPECT, and SPECT/CT. Review of angiograms and follow-up of patients with abdominal shunting served as reference standards.

RESULTS

Extrahepatic accumulation was detected by planar imaging, SPECT, and SPECT/CT in 12%, 17%, and 42% of examinations, respectively. The sensitivity for detecting extrahepatic shunting with planar imaging, SPECT, and SPECT/CT was 32%, 41%, and 100%, respectively; specificity was 98%, 98%, and 93%, respectively. The respective positive predictive values were 92%, 93%, and 89%, and the respective negative predictive values were 71%, 73%, and 100%. The therapy plan was changed according to the results of planar imaging, SPECT, and SPECT/CT in 7.8%, 8.9%, and 29% of patients, respectively.

CONCLUSION

In pre-SIRT planning, (99m)Tc-MAA SPECT/CT is valuable for identifying extrahepatic visceral sites at risk for postradioembolization complications.

Prior therapies as prognostic factors of overall survival in metastatic castration-resistant prostate cancer patients treated with [177Lu]Lu-PSMA-617. A WARMTH multicenter study (the 617 trial)

Introduction

The impact of prior therapies, especially chemotherapy, on overall survival (OS) in patients with castration-resistant prostate cancer (CRPC) receiving [¹⁷⁷Lu]Lu-PSMA-617 therapy has been the subject of controversy. Therefore, WARMTH decided to plan a multicenter retrospective analysis (the “617 trial”) to evaluate response rate and OS as well as the impact of prior therapies on OS in more than 300 patients treated with ¹⁷⁷Lu-PSMA-617.

Materials and methods

The data of 631 metastatic CRPC (mCRPC) patients from 11 different clinics were evaluated. According to the inclusion and exclusion criteria, all patients had to have received at least abiraterone or enzalutamide prior to [¹⁷⁷Lu]Lu-PSMA-617 therapy. The patients were divided into three groups: patients who had received prior chemotherapy, patients who avoided chemotherapy, and patients for whom a chemotherapy was contraindicated.

Results

The analysis included the data of 416 patients, with a median age of 71.9 years. At the time of analysis, 87 patients (20,9%) were still alive. A total of 53.6% of patients had received both abiraterone and enzalutamide; 75.5% and 26.4% had a history of chemotherapy with docetaxel and cabazitaxel, respectively. A total of 20.4% had had Ra-223. The median OS was 11.1 months. Prior chemotherapy, the existence of bone and liver metastases, as well as Eastern Cooperative Oncology Group (ECOG) status, were significant prognosticators of worse overall survival in both univariate and multivariate analyses. Patients without any prior chemotherapy showed a significantly longer OS (14.6 months). The median OS in patients who received one or two lines of chemotherapy with docetaxel or docetaxel followed by cabazitaxel, respectively, was 10.9 months and 8.9 months. There was no difference in OS between patients who had not received chemotherapy and patients for whom chemotherapy was contraindicated. The other prior therapies did not have any significant impact on OS.

Conclusion

In the present multicenter analysis, chemotherapy-naïve mCRPC patients receiving [¹⁷⁷Lu]Lu-PSMA-617 therapy had a significantly longer OS than patients with a history of chemotherapy. This remained independent in the multivariate analysis besides presence of bone and liver metastases as negative prognosticators for survival, whereas an ECOG of 0–1 is associated with a longer OS.

Electronic supplementary material

The online version of this article (10.1007/s00259-020-04797-9) contains supplementary material, which is available to authorized users.

Feasibility and Therapeutic Potential of 177Lu-Fibroblast Activation Protein Inhibitor-46 for Patients With Relapsed or Refractory Cancers: A Preliminary Study

INTRODUCTION

Fibroblast activation protein (FAP) is a member of the serine protease family and has a high expression in the stroma of approximately 90% of epithelial malignancies. The present investigation aimed to assess the feasibility, safety, and dosimetry data of 177Lu-FAPI-46 in diverse malignancies.

PATIENTS AND METHODS

Patients with advanced cancers with nonoperable tumors, or tumors refractory to conventional therapies, were enrolled. Treatment included escalating doses of 177Lu-FAPI-46 (1.85-4.44 GBq) per cycle using a combination of clinical and statistical expertise design, and intervals of 4 to 6 weeks were considered between the cycles. Biodistribution and dosimetry were examined by whole-body scans. We applied the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.03 to measure peptide-targeted radionuclide therapy (PTRT)-associated toxicity.

RESULTS

A total of 21 patients (11 females and 10 males) with a median age of 50 years (range, 6-79 years) were investigated. Of 21 participants, 18 cases were selected for PTRT. Overall, 36 PTRT cycles were performed. The median number of PTRT cycles and the median injected amount of activity in each cycle were 2 and 3.7 GBq, respectively. The dosimetric analysis revealed median absorbed doses of 0.026, 0.136, 0.886, and 0.02 with ranges of 0.023-0.034, 0.001-0.2, 0.076-1.39, and 0.002-0.2 mGy/MBq for the whole body, liver, kidneys, and spleen, respectively. The therapy was well tolerated in almost all patients.

CONCLUSIONS

The findings of this preliminary investigation might indicate the potential feasibility and safety of PTRT using 177Lu-FAPI-46 for different aggressive tumors. Moreover, the current study could be beneficial in determining the suitable amount of activity for a phase 2 study.

Comparison of the survival and tolerability of radioembolization in elderly vs. younger patients with unresectable hepatocellular carcinoma

BACKGROUND & AIMS

The European Network on Radioembolization with Yttrium-90 resin microspheres study group (ENRY) conducted a retrospective study to evaluate the outcomes among elderly (≥ 70 years) and younger patients (<70 years) with unresectable hepatocellular carcinoma (HCC) who received radioembolization at 8 European centers.

METHODS

Patients with confirmed diagnosis of unresectable HCC who either progressed following resection or locoregional treatment and/or who were considered poor candidates for chemoembolization were evaluated by a multidisciplinary team for radioembolization with (90)Y-resin microspheres (SIR-Spheres; Sirtex Medical). The survival outcome and all adverse events were compared between the two age groups.

RESULTS

Between 2003 and 2009, 128 elderly and 197 younger patients received radioembolization. Patients in both groups had similar demographic characteristics. Many elderly and younger patients alike had multinodular, BCLC stage C disease, invading both lobes (p = 0.648). Elderly patients had a lower tumor burden, a smaller median target liver volume (p = 0.016) and appeared more likely to receive segmental treatment (p = 0.054). Radioembolization was equally well tolerated in both cohorts and common procedure-related adverse events were predominantly grade 1-2 and of short duration. No significant differences in survival between the groups were found (p = 0.942) with similar median survival in patients with early, intermediate or advanced BCLC stage disease.

CONCLUSIONS

Radioembolization appears to be as well-tolerated and effective for the elderly as it is for younger patients with unresectable HCC. Age alone should not be a discriminating factor for the management of HCC patients.

Accurate assessment of long-term nephrotoxicity after peptide receptor radionuclide therapy with (177)Lu-octreotate

PURPOSE

Renal radiation during peptide receptor radionuclide therapy (PRRT) may result in glomerular damage, a potential reduction of glomerular filtration rate (GFR) and ultimately lead to renal failure. While reported PRRT nephrotoxicity is limited to data derived from serum creatinine-allowing only approximate estimates of GFR-the aim of this study is to accurately determine PRRT-induced long-term changes of renal function and associated risk factors according to state-of-the-art GFR measurement.

METHODS

Nephrotoxicity was analysed using (99m)Tc-diethylenetriaminepentaacetic acid (DTPA) clearance data of 74 consecutive patients with gastroenteropancreatic neuroendocrine tumours (GEP NET) undergoing PRRT with (177)Lu-octreotate. The mean follow-up period was 21 months (range 12-50) with a median of five GFR measurements per patient. The change of GFR was analysed by linear curve fit. Potential risk factors including diabetes mellitus, arterial hypertension, previous chemotherapy, renal impairment at baseline and cumulative administered activity were analysed regarding potential impact on renal function loss. In addition, Common Terminology Criteria for Adverse Events (CTCAE) v3.0 were used to compare nephrotoxicity determined by (99m)Tc-DTPA clearance versus serum creatinine.

RESULTS

The alteration in GFR differed widely among the patients (mean -2.1 ± 13.1 ml/min/m(2) per year, relative yearly reduction -1.8 ± 18.9%). Fifteen patients (21%) experienced a mild (2-10 ml/min/m(2) per year) and 16 patients (22%) a significant (>10 ml/min/m(2) per year) decline of GFR following PRRT. However, 11 patients (15%) showed an increase of >10 ml/min/m(2) per year. Relevant nephrotoxicity according to CTCAE (grade ≥3) was observed in one patient (1.3%) with arterial hypertension and history of chemotherapy. Nephrotoxicity according to serum creatinine was discordant to that defined by GFR in 15% of the assessments and led to underestimation in 12% of patients. None of the investigated factors including cumulative administered activity contributed to the decline of renal function.

CONCLUSION

Serious nephrotoxicity after PRRT with (177)Lu-octreotate is rare (1.3%). However, slight renal impairment (GFR loss >2 ml/min/m(2) per year) can frequently (43%) be detected by (99m)Tc-DTPA clearance assessments. Cumulative administered activity of (177)Lu-octreotate is not a major determinant of renal impairment in our study.

Predictors of overall survival in metastatic castration-resistant prostate cancer patients receiving [177Lu]Lu-PSMA-617 radioligand therapy

Prostate-specific membrane antigen (PSMA) is a promising target for the diagnosis of and therapy for metastatic castration-resistant prostate cancer (mCRPC). The aim of this study was to measure overall-survival (OS) in mCRPC patients who received either abiraterone or enzalutamide prior to PSMA therapy. The second aim of this study was to analyse the predictors of OS according to different pre-therapeutic parameters and also the responses to the first cycle of radioligand therapy (RLT) base on PSA level. Patients with mCRPC and a history of therapy with either abiraterone or enzalutamide or both, were included in this study. Different laboratory tests and pre-therapeutic parameters have been included into the analysis. One-hundred patients received a total of 347 cycles of Lu-PSMA (median: three cycles). 69 patients showed a decline in PSA two months after the first cycle, and 38 of those patients showed a PSA decline of = > 50%. The median OS was 60 weeks. In the multivariate analysis, the level of albumin, AST and haemoglobin, existence of liver metastases and a decline of > 14% in PSA level had a significant impact on overall-survival. The median OS is significantly longer in patients without hepatic involvement, with high levels of albumin and Hb and low levels of AST. A decline in PSA levels of more than 14% was the most important response parameter with regard to overall survival.

Differential Expression of Glucose Transporters and Hexokinases in Prostate Cancer with a Neuroendocrine Gene Signature: A Mechanistic Perspective for 18F-FDG Imaging of PSMA-Suppressed Tumors

Although the incidence of de novo neuroendocrine prostate cancer (PC) is rare, recent data suggest that low expression of prostate-specific membrane antigen (PSMA) is associated with a spectrum of neuroendocrine hallmarks and androgen receptor (AR) suppression in PC. Previous clinical reports indicate that PCs with a phenotype similar to neuroendocrine tumors can be more amenable to imaging by ¹⁸F-FDG than by PSMA-targeting radioligands. In this study, we evaluated the association between neuroendocrine gene signature and ¹⁸F-FDG uptake-associated genes including glucose transporters (GLUTs) and hexokinases, with the goal of providing a genomic signature to explain the reported ¹⁸F-FDG avidity of PSMA-suppressed tumors. Methods: Data-mining approaches, cell lines, and patient-derived xenograft models were used to study the levels of 14 members of the SLC2A family (encoding GLUT proteins), 4 members of the hexokinase family (genes HK1-HK3 and GCK), and PSMA (FOLH1 gene) after AR inhibition and in correlation with neuroendocrine hallmarks. Also, we characterize a neuroendocrine-like PC (NELPC) subset among a cohort of primary and metastatic PC samples with no neuroendocrine histopathology. We measured glucose uptake in a neuroendocrine-induced in vitro model and a zebrafish model by nonradioactive imaging of glucose uptake using a fluorescent glucose bioprobe, GB2-Cy3. Results: This work demonstrated that a neuroendocrine gene signature associates with differential expression of genes encoding GLUT and hexokinase proteins. In NELPC, elevated expression of GCK (encoding glucokinase protein) and decreased expression of SLC2A12 correlated with earlier biochemical recurrence. In tumors treated with AR inhibitors, high expression of GCK and low expression of SLC2A12 correlated with neuroendocrine histopathology and PSMA gene suppression. GLUT12 suppression and upregulation of glucokinase were observed in neuroendocrine-induced PC cell lines and patient-derived xenograft models. A higher glucose uptake was confirmed in low-PSMA tumors using a GB2-Cy3 probe in a zebrafish model. Conclusion: A neuroendocrine gene signature in neuroendocrine PC and NELPC associates with a distinct transcriptional profile of GLUTs and hexokinases. PSMA suppression correlates with GLUT12 suppression and glucokinase upregulation. Alteration of ¹⁸F-FDG uptake-associated genes correlated positively with higher glucose uptake in AR- and PSMA-suppressed tumors. Zebrafish xenograft tumor models are an accurate and efficient preclinical method for monitoring nonradioactive glucose uptake.

Theranostic Approach in Breast Cancer: A Treasured Tailor for Future Oncology

ABSTRACT

Breast cancer is the most frequent invasive malignancy and the second major cause of cancer death in female subjects mostly due to the considerable diagnostic delay and failure of therapeutic strategies. Thus, early diagnosis and possibility to monitor response to the treatment are of utmost importance. Identification of valid biomarkers, in particular new molecular therapeutic targets, that would allow screening, early patient identification, prediction of disease aggressiveness, and monitoring response to the therapeutic regimen has been in the focus of breast cancer research during recent decades. One of the intensively developing fields is nuclear medicine combining molecular diagnostic imaging and subsequent (radio)therapy in the light of theranostics. This review aimed to survey the current status of preclinical and clinical research using theranostic approach in breast cancer patients with potential to translate into conventional treatment strategies alone or in combination with other common treatments, especially in aggressive and resistant types of breast cancer. In addition, we present 5 patients with breast cancer who were refractory or relapsed after conventional therapy while presumably responded to the molecular radiotherapy with 177Lu-trastuzumab (Herceptin), 177Lu-DOTATATE, and 177Lu-FAPI-46.

The Role of Adding Somatostatin Analogues to Peptide Receptor Radionuclide Therapy as a Combination and Maintenance Therapy

Purpose: Although somatostatin analogues (SSA) and peptide receptor radionuclide therapy (PRRT) are validated therapies in patients with advanced gastroenteropancreatic neuroendocrine tumors (GEP-NET), it remains unclear whether SSA combined with PRRT or as maintenance therapy can provide prolonged survival compared with patients treated with PRRT alone. In this retrospective study, we aimed to investigate whether there is a survival benefit to adding SSA to PRRT as a combination therapy and/or maintenance therapy.Patients and Methods: The investigation included 168 patients with unresectable GEP-NETs treated at the University Hospital Bonn, Bonn, Germany. The patients were divided into two main groups: PRRT monotherapy (N = 81, group 1) and PRRT plus SSA (N = 87, group 2) as combined therapy with PRRT and/or as maintenance therapy after PRRT.Results: Data for overall survival (OS) were available from 168 patients, of whom 160 had data for progression-free survival (PFS). The median PFS was 27 months in group 1 versus 48 months in group 2 (P = 0.012). The median OS rates were 47 months in group 1 and 91 months in group 2 (P < 0.001). The death-event rates were lower in group 2 (26%) than in group 1 (63%). SSA as a combination therapy with PRRT and/or as a maintenance therapy showed a clinical benefit rate (objective response or stable disease) of 95%, which was significantly higher than group 1 (79%).Conclusions: SSA as a combination therapy and/or maintenance therapy may play a significant role in tumor control in patients with GEP-NET who underwent a PRRT. Clin Cancer Res; 24(19); 4672-9. ©2018 AACR.