There was no difference in PFS and OS between SBRT and conventionally treated patients despite an imbalance of prognostic factors. We observed a tendency of an improved disease control rate in the SBRT group and they experienced better HRQL and less toxicity. SBRT is convenient for patients and should be considered standard treatment for patients with inoperable stage I NSCLC.
Eliminating microscopic residual disease with α-particle radiation is theoretically appealing. After extensive preclinical work with αparticle-emitting 211 At, we performed a phase I trial with intraperitoneal α-particle therapy in epithelial ovarian cancer using 211 At conjugated to MX35, the antigen-binding fragments-F(ab′) 2-of a mouse monoclonal antibody. We now present clinical outcome data and toxicity in a long-term follow-up with individual absorbed dose estimations. Methods: Twelve patients with relapsed epithelial ovarian cancer, achieving a second complete or nearly complete response with chemotherapy, received intraperitoneal treatment with escalating (20-215 MBq/L) activity concentrations of 211 At-MX35 F(ab′) 2. Results: The activity concentration was escalated to 215 MBq/L without any dose-limiting toxicities. Most toxicities were low-grade and likely related to the treatment procedure, not clearly linked to the α-particle irradiation, with no observed hematologic toxicity. One grade 3 fatigue and 1 grade 4 intestinal perforation during catheter implantation were observed. Four patients had a survival of more than 6 y, one of whom did not relapse. At progression, chemotherapy was given without signs of reduced tolerability. Overall median survival was 35 mo, with a 1-, 2-, 5-, and 10-y survival of 100%, 83%, 50%, and 25%, respectively. Calculations of the absorbed doses showed that a lower specific activity is associated with a lower single-cell dose, whereas a high specific activity may result in a lower central dose in microtumors. Individual differences in absorbed dose to possible microtumors were due to variations in administered activity and the specific activity. Conclusion: No apparent signs of radiation-induced toxicity or decreased tolerance to relapse therapy were observed. The dosimetric calculations show that further optimization is advisable to increase the efficacy and reduce possible long-term toxicity.
Purpose
Radionuclide therapy with 177Lu-DOTATATE is well established for patients with advanced somatostatin receptor–positive neuroendocrine tumors with a standard schedule of 7.4 GBq at four occasions. However, this approach does not consider individual variability affecting the tumor radiation dose or dose to organs at risk. Therefore, it is important to assess more personalized strategies. The aim of this phase II trial was to evaluate individualized 177Lu-DOTATATE for which the number of cycles varied based on renal dosimetry.
Methods
Patients were eligible if they had a progressive, somatostatin receptor–positive neuroendocrine tumor with a Ki 67 labeling index < 20%. They received cycles of 7.4 GBq of 177Lu-DOTATATE at 10 ± 2-week intervals until a predefined radiation dose to the kidneys was reached. The primary endpoint was objective tumor response (RECIST v 1.1). Secondary endpoints included progression-free survival (PFS), overall survival (OS), and toxicity (CTCAE v. 4.0).
Results
Ninety-six patients who had received a median of 5 cycles (range 1–9) were evaluable for efficacy. The objective tumor response was 16% partial response, 66% stable disease, and 19% progressive disease. The median PFS and OS were 29 months and 47 months, respectively, and were significantly associated with kidney dose, performance status, and Ki 67 levels but not with tumor origin. The overall toxicity was mild, and the most common events were grade 1–2 anemia, thrombocytopenia, fatigue, nausea, and diarrhea. Grade 3–4 toxicity occurred in < 10% of patients and was mostly hematological, with no grade 3–4 renal toxicity.
Conclusion
Individualized treatment with 177Lu-DOTATATE based on renal dosimetry is clearly feasible with low toxicity and promising efficacy, showing the potential to further improve outcome beyond the standard approach, and should be further assessed in randomized trials.
Trial registration
EudraCT 2011–000,240-16. NCT01456078. https://clinicaltrials.gov/ct2/show/NCT01456078
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