Imaging Androgen Receptors in Breast Cancer with (18)F-fluoro-5α-dihydrotestosterone-PET: A Pilot Study

Most breast cancers express androgen receptors (AR). This prospective imaging sub-study explored imaging AR with (18)F-fluoro-5α-dihydrotestosterone (FDHT)-PET in patients with metastatic breast cancer (MBC) receiving selective AR modulation (SARM) therapy (GTx-024, GTx, Inc). Methods: 11 post-menopausal women with estrogen receptor positive MBC underwent FDHT-PET/CT at baseline, 6, and 12 weeks after starting SARM therapy. Abnormal tumor FDHT uptake was quantified using maximum SUV (SUVmax). AR status was determined from tumor biopsy specimens. FDHT-SUVmax percent change between scans was calculated. Best overall response was categorized as clinical benefit (CB: non-progressive disease [PD]), or PD using RECIST 1.1. Results: Median baseline FDHT-SUVmax was 4.1 (range 1.4-5.9) for AR+ tumors versus 2.3 (range 1.5-3.2) for AR- tumors (p=0.22). Quantitative AR expression and baseline FDHT uptake were weakly correlated (Pearson rho=0.39, p=0.30). Seven participants with CB at 12 weeks tended to have larger declines in FDHT uptake compared to those with PD at both 6 (median decline, range: -26.8%, -42.9 to -14.1% vs. -3.7%, -31% to +29%, respectively, p=0.11) and 12 weeks (median decline, range: -35.7%, -69.5 to -7.7% vs. -20.1%, -26.6% to +56.5%, respectively, p=0.17) after starting GTx-024. Conclusion: This hypothesis-generating data suggests that FDHT-PET/CT is worth further study as an imaging biomarker for evaluating response of MBC to SARM therapy and reiterates the feasibility of including molecular imaging in multidisciplinary therapeutic trials

Prospective SPECT-CT organ dosimetry-driven radiation-absorbed dose escalation using the In-111 (111In)/yttrium 90 (90Y) ibritumomab tiuxetan (Zevalin ®) theranostic pair in patients with lymphoma at myeloablative dose levels

PURPOSE: We prospectively evaluated the feasibility of SPECT-CT/planar organ dosimetry-based radiation dose escalation radioimmunotherapy in patients with recurrent non-Hodgkin\u27s lymphoma using the theranostic pair of METHODS: 24 patients with CD20-positive relapsed or refractory rituximab-sensitive, low-grade, mantle cell, or diffuse large-cell NHL, with normal organ function, platelet counts \u3e 75,000/mm RESULTS: Patient-specific hybrid SPECT/CT + planar organ dosimetry was feasible in all 18 cases and used to determine the patient-specific therapeutic dose and guide dose escalation (26.8 ± 7.3 MBq/kg (mean), 26.3 MBq/kg (median) of CONCLUSIONS: Patient-specific outpatien

Interim FDG-PET/CT for Response Assessment of Lymphoma

The clinical use and prognostic value of interim FDG-PET/CT (iPET/CT), which is performed after treatment initiation but prior to its completion, varies by lymphoma subtype. Evidence supporting the prognostic value of iPET/CT is more robust for classical Hodgkin lymphoma (cHL), and in this lymphoma subtype, response-adapted treatment approaches guided by iPET/CT are a widely used standard of care for first-line therapy. The data supporting use of iPET/CT among patients with non-Hodgkin lymphoma (NHL) is less well-established, but failure to achieve complete metabolic response on iPET/CT is generally considered a poor prognostic factor with likely consequences for progression free survival. This review will present the available evidence supporting use of iPET/CT in lymphoma patients, particularly as it relates to prognostication and the ability to inform response-adapted treatment strategies. The latter will be addressed through a discussion on the major iPET-response adapted clinical trials with mention of ongoing trials. Special attention will be given to cHL and a few subtypes of NHL, including diffuse large B cell lymphoma (DLBCL), follicular lymphoma (FL), and peripheral T cell lymphoma (PTCL)

Refinement of the Lugano classification response criteria for lymphoma in the era of immunomodulatory therapy

Abstract Uniformly adopted response criteria are essential for assessment of therapies incorporating conventional chemotherapy and chemoimmunotherapy regimens. Recently, immunomodulatory agents, such as immune checkpoint inhibitors, have demonstrated impressive activity in a broad range of lymphoma histologies. However, these agents may be associated with clinical and imaging findings during treatment suggestive of progressive disease (PD) despite evidence of clinical benefit (eg, tumor flare or pseudo-progression). Considering this finding as PD could lead to patients being prematurely removed from a treatment from which they actually stand to benefit. This phenomenon has been well described with checkpoint blockade therapy in solid tumors and anecdotally seen in lymphoma as well. To address this issue in the context of lymphoma immunomodulatory therapy, a workshop was convened to provide provisional recommendations to modify current response criteria in patients receiving these and future agents in clinical trials. The term “indeterminate response” was introduced to identify such lesions until confirmed as flare/pseudo-progression or true PD by either biopsy or subsequent imaging.</jats:p

Refractory myeloid sarcoma with a FIP1L1-PDGFRA rearrangement detected by clinical high throughput somatic sequencing

Next generation sequencing (NGS) is increasingly being used clinically to characterize the molecular alterations found in patients’ tumors. These testing results have the potential to affect clinical care by guiding therapeutic approaches based upon genotype. NGS based testing approaches have a distinct advantage over provider-ordered single gene testing in that they can detect unexpected, yet clinically important genetic changes. Here, we illustrate this principle with the case of a 33-year-old man with myeloid sarcoma that was refractory to six different chemotherapeutic regimens. Our clinical NGS assay detected an unanticipated FIP1L1-PDGFRA rearrangement in his tumor. The patient was immediately placed on Imatinib therapy to which he responded, and remains in remission 10 months after the rearrangement was initially detected

Prediction of the Need for Surgical Intervention in Obstructive Crohn's Disease by F-18-FDG PET/CT

We preoperatively determined the accuracy of F-18-FDG PET/CT for differentiating fixed muscle hypertrophy and fibrotic stenoses from acute transmural inflammatory stenoses in patients with Crohn's disease (CD) scheduled to undergo surgical resection for obstructive symptoms. Methods: Seventeen patients with known CD prospectively underwent F-18-FDG PET/CT before already-planned surgery for obstructive symptoms. Image interpretation was by consensus of 2 readers with knowledge of patient participation in the study but not of other clinical history. Lesions were qualitatively graded on a 5-point scale for the presence of increased F-18-FDG uptake consistent with active inflammation. Maximum lean standardized uptake value (SULmax) was determined for lesions scored 1 or more. Imaging results were compared with the pathologic grading of inflammation and predominant histopathologic subtype for each patient's surgical specimen, whether mainly inflammation, fibrosis, or muscle hypertrophy. Results: Thirteen of the 17 patients underwent surgery (median, 28 d after PET/CT; range, 2-148 d), and 12 of these 13 had histopathologic correlation. Despite the predominant histopathologic subtype (inflammation, 5; fibrosis, 4; and muscle hypertrophy, 3), acute and chronic inflammation, fibrosis (median, 50%; range, 40%-90%), and muscle hypertrophy (median, 20-fold thickening; range, 9- to 40-fold thickening) were found in all patients. SULmax was significantly higher in severe than in mild-to-moderate chronic inflammation (8.2 +/- 2.8 vs. 4.7 +/- 2.5, P = 0.04). No patient with predominantly fibrosis or muscle hypertrophy (n = 7) had an SULmax greater than 8. Visually, 10 of 12 patients on PET/CT were considered to have active inflammation of the bowel. Conclusion: Patients with CD who undergo surgery for obstructive symptoms have histopathologically mixed findings of inflammation, fibrosis, and muscle hypertrophy. Qualitative PET interpretations were quite sensitive, but additional semiquantitative analyses using SULmax helped identify patients with active inflammation. This information may be beneficial for referring gastroenterologists considering medical therapy versus surgery for patients with CD who present with obstructive symptoms

Prospective SPECT-CT Organ Dosimetry-Driven Radiation-Absorbed Dose Escalation Using the In-111 (111In)/Yttrium 90 (90Y) Ibritumomab Tiuxetan (Zevalin®) Theranostic Pair in Patients with Lymphoma at Myeloablative Dose Levels

Purpose: We prospectively evaluated the feasibility of SPECT-CT/planar organ dosimetry-based radiation dose escalation radioimmunotherapy in patients with recurrent non-Hodgkin’s lymphoma using the theranostic pair of 111In and 90Y anti-CD20 ibritumomab tiuxetan (Zevalin®) at myeloablative radiation-absorbed doses with autologous stem cell support. We also assessed acute non-hematopoietic toxicity and early tumor response in this two-center outpatient study. Methods: 24 patients with CD20-positive relapsed or refractory rituximab-sensitive, low-grade, mantle cell, or diffuse large-cell NHL, with normal organ function, platelet counts &gt; 75,000/mm3, and &lt;35% tumor involvement in the marrow were treated with Rituximab (375 mg/m2) weekly for 4 consecutive weeks, then one dose of cyclophosphamide 2.5 g/m2 with filgrastim 10 mcg/kg/day until stem cell collection. Of these, 18 patients with successful stem cell collection (at least 2 × 106 CD34 cells/kg) proceeded to RIT. A dosimetric administration of 111In ibritumomab tiuxetan (185 MBq) followed by five sequential quantitative planar and one SPECT/CT scan was used to determine predicted organ radiation-absorbed dose. Two weeks later, 90Y ibritumomab tiuxetan was administered in an outpatient setting at a cohort- and patient-specific predicted organ radiation-absorbed dose guided by a Continuous Response Assessment (CRM) methodology with the following cohorts for dose escalation: 14.8 MBq/kg, and targeted 18, 24, 28, and 30.5 Gy to the liver. Autologous stem cell infusion occurred when the estimated marrow radiation-absorbed dose rate was predicted to be &lt;1 cGy/h. Feasibility, short-term toxicities, and tumor response were assessed. Results: Patient-specific hybrid SPECT/CT + planar organ dosimetry was feasible in all 18 cases and used to determine the patient-specific therapeutic dose and guide dose escalation (26.8 ± 7.3 MBq/kg (mean), 26.3 MBq/kg (median) of 90Y (range: 12.1–41.4 MBq/kg)) of ibritumomab tiuxetan that was required to deliver 10 Gy to the liver. Infused stem cells engrafted rapidly. The most common treatment-related toxicities were hematological and were reversible following stem cell infusion. No significant hepatotoxicity was seen. One patient died from probable treatment-related causes—pneumonia at day 27 post-transplant. One patient at dose level 18 Gy developed myelodysplastic syndrome (MDS), 4 patients required admission post-90Y RIT for febrile neutropenia, 16/18 patients receiving 90Y ibritumomab tiuxetan (89%) responded to the therapy, with 13 CR (72%) and 3/18 PR (17%), at 60 days post-treatment. Two patients had progressive disease at sixty days. One patient was lost to follow-up. Median time to progression was estimated to be at least 13 months. MTD to the liver is greater than 28 Gy, but the MTD was not reached as the study was terminated due to unexpected discontinuation of availability of the therapeutic agent. Conclusions: Patient-specific outpatient 90Y ibritumomab tiuxetan RIT with myeloablative doses of RIT up to a targeted 30.5 Gy to the liver is feasible, guided by prospective SPECT/CT + planar imaging with the theranostic pair of 111In and 90Y anti-CD20, with outpatient autologous stem cell transplant support. Administered activity over 5 times the standard FDA-approved activity was well-tolerated. The non-hematopoietic MTD in this study exceeds 28 Gy to the liver. Initial tumor responses were common at all dose levels. This study supports the feasibility of organ dosimetry-driven patient-specific dose escalation in the treatment of NHL with stem cell transplant and provides additional information on the radiation tolerance of the normal liver to radiopharmaceutical therapy