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- Bragina, Olga, et al.
(författare)
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Phase I clinical evaluation of 99mTc-labeled Affibody molecule for imaging HER2 expression in breast cancer
- 2023
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Ingår i: Theranostics. - : Ivyspring International Publisher. - 1838-7640. ; 13:14, s. 4858-4871
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Tidskriftsartikel (refereegranskat)abstract
- The determination of tumor human epidermal growth factor receptor type 2 (HER2) status is of increasing importance with the recent approval of more efficacious HER2-targeted treatments. There is a lack of suitable methods for clinical in vivo HER2 expression assessment. Affibody molecules are small affinity proteins ideal for imaging detection of receptors, which are engineered using a small (molecular weight 6.5 kDa) nonimmunoglobulin scaffold. Labeling of Affibody molecules with positron emitters enabled the development of sensitive and specific agents for molecular imaging. The development of probes for SPECT would permit the use of Affibody-based imaging in regions where PET is not available. In this first-in-human study, we evaluated the safety, biodistribution, and dosimetry of the Tc-99m-ZHER2:41071 Affibody molecule developed for SPECT/CT imaging of HER2 expression.Methods: Thirty-one patients with primary breast cancer were enrolled and divided into three cohorts (injected with 500, 1000, or 1500 mu g ZHER2:41071) comprising at least five patients with high (positive) HER2 tumor expression (IHC score 3+ or 2+ and ISH positive) and five patients with low (IHC score 2+ or 1+ and ISH negative) or absent HER2 tumor expression. Patients were injected with 451 +/- 71 MBq Tc-99m-ZHER2:4107. Planar scintigraphy was performed after 2, 4, 6 and 24 h, and SPECT/CT imaging followed planar imaging 2, 4 and 6 h after injection.Results: Injections of Tc-99m-ZHER2:41071 were well tolerated and not associated with adverse events. Normal organs with the highest accumulation were the kidney and liver. The effective dose was 0.019 +/- 0.004 mSv/MBq. Injection of 1000 mu g provided the best standard discrimination between HER2-positive and HER2-low or HER2-negative tumors 2 h after injection (SUVmax 16.9 +/- 7.6 vs. 3.6 +/- 1.4, p < 0.005). The Tc-99m-ZHER2:41071 uptake in HER2-positive lymph node metastases (SUVmax 6.9 +/- 2.4, n = 5) was significantly (p < 0.05) higher than that in HER2-low/negative lymph nodes (SUVmax 3.5 +/- 1.2, n = 4). Tc-99m-ZHER2:41071 visualized hepatic metastases in a patient with liver involvement.Conclusions: Injections of Tc-99m-ZHER2:41071 appear safe and exhibit favorable dosimetry. The protein dose of 1000 mu g provides the best discrimination between HER2-positive and HER2-low/negative expression of HER2 according to the definition used for current HER2-targeting drugs.
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| 2. |
- Bragina, Olga, et al.
(författare)
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Phase I Trial of 99mTc-(HE)3-G3, a DARPin-Based Probe for Imaging of HER2 Expression in Breast Cancer
- 2022
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 63:4, s. 528-535
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Tidskriftsartikel (refereegranskat)abstract
- Radionuclide molecular imaging of human epidermal growth factor receptor type 2 (HER2) expression may enable a noninvasive discrimination between HER2-positive and HER2-negative breast cancers for stratification of patients for HER2-targeted treatments. DARPin (designed ankyrin repeat proteins) G3 is a small (molecular weight, 14 kDa) scaffold protein with picomolar affinity to HER2. The aim of this first-in-humans study was to evaluate the safety, biodistribution, and dosimetry of 99mTc-(HE)3-G3.Methods: Three cohorts of patients with primary breast cancer (each including at least 4 patients with HER2-negative and 5 patients with HER2-positive tumors) were injected with 1,000, 2,000, or 3,000 μg of 99mTc-(HE)3-G3 (287 ± 170 MBq). Whole-body planar imaging followed by SPECT was performed at 2, 4, 6, and 24 h after injection. Vital signs and possible side effects were monitored during imaging and up to 7 d after injection.Results: All injections were well tolerated. No side effects were observed. The results of blood and urine analyses did not differ before and after studies. 99mTc-(HE)3-G3 cleared rapidly from the blood. The highest uptake was detected in the kidneys and liver followed by the lungs, breasts, and small intestinal content. The hepatic uptake after injection of 2,000 or 3,000 μg was significantly (P < 0.05) lower than the uptake after injection of 1,000 μg. Effective doses did not differ significantly between cohorts (average, 0.011 ± 0.004 mSv/MBq). Tumor–to–contralateral site ratios for HER-positive tumors were significantly (P < 0.05) higher than for HER2-negative at 2 and 4 h after injection.Conclusion: Imaging of HER2 expression using 99mTc-(HE)3-G3 is safe and well tolerated and provides a low absorbed dose burden on patients. This imaging enables discernment of HER2-positive and HER2-negative breast cancer. Phase I study data justify further clinical development of 99mTc-(HE)3-G3.
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