Safety and Efficacy of Extended Therapy with [177Lu]Lu-PSMA: A German Multicenter Study

Prospective results have demonstrated favorable safety and efficacy of [177Lu]Lu-PSMA radiopharmaceutical therapy for up to 6 cycles in men with metastatic castration-resistant prostate cancer. However, no systematic data are available outlining the feasibility of extended therapy beyond 6 cycles. We aim to evaluate the safety and efficacy of extended [177Lu]Lu-PSMA radiopharmaceutical therapy in patients who have received more than 6 cycles. Methods: In total, 111 patients were included in this multicenter retrospective analysis. Based on individual decisions, patients underwent uninterrupted continuation of therapy (continuous treatment) or reexposure after a therapy break (rechallenge treatment) between 2014 and 2023. Overall survival, 50% prostate-specific antigen (PSA) decline (measured 8-12 wk after treatment initiation or rechallenge), PSMA PET response, and grades per Common Terminology Criteria for Adverse Events were assessed. χ2 tests, multivariable Cox regression analysis, and log-rank tests were applied for statistical analyses. Results: Patients received extended treatment with [177Lu]Lu-PSMA, either as a continuous treatment (43/111, 38.7%) or as a rechallenge (68/111, 61.3%) treatment, with median cumulative doses of 57.4 or 60.8 GBq, respectively. Overall survival from the initiation of [177Lu]Lu-PSMA was 31.3, 23.2, and 40.2 mo for the entire cohort, the continuous treatment group, and the rechallenge treatment group, respectively. The initial 50% PSA decline was significantly higher in the retreated group than in the continuous group (57/63 [90.4%] vs. 26/42 [61.9%]; P = 0.006). A 50% PSA decline was observed in 23 of 62 patients (37.1%) after the first rechallenge. The rate of grades 3-4 toxicity was comparable between continuous and rechallenge treatments (anemia, 7/43 [16.3%] vs. 13/68 [19.1%)], P = 0.6; leukocytopenia, 1/43 [2.3%] vs. 2/67 [3.0%], P = 0.3; thrombocytopenia, 3/43 [7.0%] vs. 3/68 [4.4%], P = 0.3; renal, 2/43 [4.7%] vs. 5/68 [7.4%], P = 0.2). Conclusion: Extended therapy with [177Lu]Lu-PSMA is safe and has not been associated with increased grades 3-4 toxicity. Patient candidates for extended treatment experienced a favorable median survival of 31.3 mo from the first administration. Response under [177Lu]Lu-PSMA rechallenge demonstrated preserved efficacy of [177Lu]Lu-PSMA after a treatment break.

What Role Does PET/MRI Play in Musculoskeletal Disorders?

Musculoskeletal disorders of nononcological origin are one of the most frequent reasons for consultation. Patients suffering from musculoskeletal disorders also consult more than once for the same reason. This results in multiple clinical follow-ups after several radiological and serum examinations, the main ones including X-rays targeting the painful anatomical region and inflammatory serum parameters. As part of their work up, patients suffering from musculoskeletal disorders often require multisequence, multi-parameter MRI. PET/MRI is a promising imaging modality for their diagnosis, with the added advantage of being able to be performed in a single visit. PET/MRI is particularly useful for diagnosing osteomyelitis, spondylodiscitis, arthritis, many pediatric pathologies, and a wide range of other musculoskeletal pathologies. PET/MRI is already used to diagnose malignant bone tumors such as osteosarcoma. However, current knowledge of the indications for PET/MRI in nononcological musculoskeletal disorders is based on studies involving only a few patients. This review focuses on the usefulness of PET/MRI for diagnosing nononcological musculoskeletal disorders.

Highly Symptomatic Progressing Cardiac Paraganglioma With Intracardiac Extension Treated With 177Lu-DOTATATE: A Case Report

INTRODUCTION

Primary cardiac paragangliomas are rare tumors. Metastatic disease is even rarer. Surgical management is technically challenging, and sometimes even impossible. Available therapeutic modalities for metastatic disease include external beam radiation therapy as well as systemic treatments, namely ¹³¹I-MIBG and more recently, peptide receptor radionuclide therapy (PRRT) with ¹⁷⁷Lu-DOTATATE. To our knowledge, this is the first case of progressive unresectable cardiac paraganglioma with intracardiac extension treated with dosimetry based personalized PRRT to be reported. This case is of particular interest since it documents for the first time the efficacy, and especially the safety of the ¹⁷⁷Lu-DOTATATE PRRT in this precarious context for which therapeutic options are limited.

CASE PRESENTATION

A 47-year-old man with no medical history consulted for rapidly decreasing exercise tolerance. The investigation demonstrated an unresectable progressing metastatic cardiac paraganglioma with intracardiac extension. The patient was treated with personalized ¹⁷⁷Lu-DOTATATE PRRT and showed complete symptomatic and partial anatomical responses, with a progression-free survival of 13 months.

CONCLUSIONS

PRRT with ¹⁷⁷Lu-DOTATATE should be considered for inoperable cardiac paraganglioma. No major hemodynamic complications were experienced. Therapy resulted in safety and substantially improved quality of life.

On the mechanisms of immunodominance in cytotoxic T lymphocyte responses to minor histocompatibility antigens

Although there are numerous minor histocompatibility antigens (MiHA), T cell responses leading to graft-versus-host (GVH) and graft-versus-tumor effects involve only a small number of immunodominant MiHA. The goal of the present study was to analyze at the cellular and molecular levels the mechanisms responsible for MiHA immunodominance. Cytotoxic T lymphocytes (CTL) generated in eight combinations of H2b strains of mice were tested against syngeneic targets sensitized with HPLC-fractionated peptides eluted from immunizing cells. The number of dominant MiHA was found to range from as little as two up to ten depending on the strain combination used. The nature of dominant MiHA was influenced by both the antigen profile of the antigen-presenting cells (APC) and the repertoire of responding CTL. When C57BL/6 dominant MiHA (B6dom) and H-Y were presented on separate APC, they showed similar immunogenicity. In contrast, when they were presented on the same APC, B6dom MiHA totally dominated H-Y. B6dom MiHA did not suppress anti-H-Y responses by acting as T cell receptor antagonists for anti-H-Y CTL, nor were anti-B6dom CTL precursors more abundant than anti-H-Y CTL precursors. Dominance resulted from competition for the APC surface between anti-B6dom and anti-H-Y CTL; the crucial difference between the dominant and the dominated MiHA appears to depend on the differential avidity of their respective CTL for APC. The only B6dom epitope thus far identified is the nonapeptide AAPDNRETF presented by H2-D(b). We found that compared with other known D(b)-binding peptides, AAPDNRETF is expressed at very high levels on the cell surface, binds to the D(b) molecule with very high affinity, and dissociates very slowly from its presenting class I molecule. These data indicate that one cannot predict which MiHA will be dominant or dominated based simply on their respective immunogenicity when presented on separate APC. Indeed, the avidity of T cell/APC interactions appears to determine which antigen(s) will trigger T cell responses when numerous epitopes are presented by the same APC.

[University and community health center collaboration]

Nurses from a CLSC in Hull, Quebec are defining a positive role for community health nurses in a multidisciplinary environment. They base their professional day-to-day practice on Orem's conceptual nursing framework. Many of these home care nurses studied in a post-RN baccalaureate nursing program at the University of Quebec in Hull, where they learned different aspects of conceptual frameworks and the nursing process. Two nurse clinicians and a nurse administrator submitted a project based on Orem's model to the administrators of their community health centre. Once it was approved, a nursing professor from the university agreed to act as a consultant and principal researcher to implement the process. The authors describe this three-year collaborative project between home care nurses and the researcher. This includes its objectives, the participants' roles, the tools developed, the process, and the repercussions on nursing care, nurses, and the multidisciplinary team.

Sex steroid concentrations in plasma from the canine deferential vein

Sex steroid concentrations in plasma collected from the canine deferential vein were measured, after separation, by radioimmunoassay. The concentrations found were compared with those in the peripheral plasma. The mean concentrations of androstenedione, testosterone, 5 alpha-dihydrotestosterone, 5 alpha-androstane-3 alpha, 17 beta-diol, 5 alpha-androstane-3 beta, 17 beta-diol and oestradiol-17 beta were 13.2, 14.7, 8.9, 4.6, 8.0 and 7.5 fold higher respectively in plasma from the deferential vein than in peripheral plasma. A close anatomical relationship was found between the vasa deferentia, the deferential vein and the peripheral plasma as well as between the deferential vein and the prostate gland. These findings emphasize and extend earlier conclusions that high levels of sex steroids present in the deferential vein could have a local influence on the growth of the prostate.

Androgen levels in the lipid of the canine vas deferens and peripheral plasma

Radioimmunoassays were used for the measurement of several androgens in canine plasma and in the liquid of the vas deferens. Large variations in the plasma concentrations of androstenedione, testosterone and 5 alpha-dihydrotestosterone occurred during a period of 24 h, but there was no evidence of a circadian rhythm. The ratios of the androgen concentration in the liquid of the vas deferens compared with that in the peripheral plasma were: androstenedione, 4.6; testosterone, 1.9; 5 alpha-dihydrotestosterone, 13.6; 5 alpha-androstane-3 alpha, 17 beta-diol, 17.0; 5 alpha-diol, 22.4. These high levels of androgens in the liquid of the vas deferens could play a role in the development of prostatic hypertrophy.