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Ionising radiation (IR) is a form of energy that travels as electromagnetic waves or particles. While it is vital in medical and occupational health settings, IR can also damage DNA, leading to mutations, chromosomal aberrations, and transcriptional changes that disrupt the functions of certain cell regulators, genes, and transcription factors. These disruptions can alter functions critical for cancer development, progression, and treatment response. Additionally, IR can affect various cellular proteins and their regulators within different cell signalling pathways, resulting in physiological changes that may promote cancer development, progression, and resistance to treatment. Understanding these impacts is crucial for developing strategies to mitigate the harmful effects of IR exposure and improve cancer treatment outcomes. This review focuses on specific genes and protein biomarkers regulated in response to chronic IR exposure, and how their regulation impacts disease onset, progression, and treatment response., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 Mzizi, Mbambara, Moetlhoa, Mahapane, Mdanda, Sathekge and Kgatle.)

Background: Actinium-225 ( 225 Ac) prostate-specific membrane antigen (PSMA) radioligand therapy (RLT) is a novel therapy for metastatic castration-resistant prostate cancer (mCRPC). We aimed to report the safety and antitumour activity of 225 Ac-PSMA RLT of mCRPC in a large cohort of patients treated at multiple centres across the world., Methods: This retrospective study included patients treated at seven centres in Australia, India, Germany, and South Africa. We pooled data of consecutive patients of any age and Eastern Cooperative Oncology Group performance status with histopathologically confirmed adenocarcinoma of the prostate who were treated with one or more cycles of 8 MBq 225 Ac-PSMA RLT administered intravenously for mCRPC. Previous lines of mCRPC treatment included taxane-based chemotherapy, androgen-receptor-axis inhibitors, lutetium-177 ( 177 Lu) PSMA RLT, and radium-223 dichloride. The primary outcomes were overall survival and progression-free survival., Findings: Between Jan 1, 2016, and May 31, 2023, 488 men with mCRPC received 1174 cycles of 225 Ac-PSMA RLT (median two cycles, IQR 2-4). The mean age of the patients was 68·1 years (SD 8·8), and the median baseline prostate-specific antigen was 169·5 ng/mL (IQR 34·6-519·8). Previous lines of treatment were docetaxel in 324 (66%) patients, cabazitaxel in 103 (21%) patients, abiraterone in 191 (39%) patients, enzalutamide in 188 (39%) patients, 177 Lu-PSMA RLT in 154 (32%) patients, and radium-223 dichloride in 18 (4%) patients. The median follow-up duration was 9·0 months (IQR 5·0-17·5). The median overall survival was 15·5 months (95% CI 13·4-18·3) and median progression-free survival was 7·9 months (6·8-8·9). In 347 (71%) of 488 patients, information regarding treatment-induced xerostomia was available, and 236 (68%) of the 347 patients reported xerostomia after the first cycle of 225 Ac-PSMA RLT. All patients who received more than seven cycles of 225 Ac-PSMA RLT reported xerostomia. Grade 3 or higher anaemia occurred in 64 (13%) of 488 patients, leukopenia in 19 (4%), thrombocytopenia in 32 (7%), and renal toxicity in 22 (5%). No serious adverse events or treatment-related deaths were recorded., Interpretation: 225 Ac-PSMA RLT shows a substantial antitumour effect in mCRPC and represents a viable therapy option in patients treated with previous lines of approved agents. Xerostomia is a common side-effect. Severe bone marrow and renal toxicity are less common adverse events., Funding: None., Competing Interests: Declaration of interests MMS reports grants or contracts from Novartis; payment or honoraria from Bayer, Johnson & Johnson, NTP, and Sanofi; support for attending meetings from the International Atomic Energy Agency; and receipt of equipment or materials from POINT Biopharma. ME reports grants or contracts from Blue Earth Diagnostics; royalties from patent on radiohybrid PSMA; consulting fees from Novartis, Point Biopharma, payment from Novartis; payment for expert testimony from Novartis, Bayer, Telix, and Blue Earth Diagnostics; support for attending meetings from Blue Earth Diagnostics; and patent ownership on radiohybrid PSMA. TH reports grants or contracts from Siemens. CK reports patent ownership. NPL reports contracts from Telix, Ipsen/Ariceum, and Clarity; receipt of educational material from Telix; support for attending meetings from Telix; participation on the advisory board of Telix; and family stock ownership at Clarity. ASi reports support for attending meetings from Telix International, Australia and participation on Data Safety Monitoring Borad for Telix International. RT reports payment or honoraria from Astella, AstraZeneca, Bayer, Bristol Myers Squibb, Janssen, Merck, MSD, Novartis, Orion, Pfizer, Roche, and Sanofi; support for attending meetings from Bayer, Janssen, Orion, Pfizer, and Roche; participation on Data Safety Monitoring Board or Advisory Board of Astellas, AstraZeneca, Bayer, Bristol Myers Squibb, Eisei, EUSA, IPSEN, Janssen, Merck, MSD, Novartis, Orion, Pfizer, Philogen, Roche, and Sanofi; stock ownership at Bayer; and financial or non-financial interests at Thieme compliance and Elsevier. AM reports patents owning a patent for treatment of PSMA-expressing cancers. All other authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Hypoxia leads to changes in tumor microenvironment (upregulated CAFs) with resultant aggressiveness. A key factor in the physiological response to hypoxia is hypoxia-inducible factor-1alpha (HIF-1α). [ 68 Ga]Ga-FAPI PET imaging has been demonstrated in various cancer types. We hypothesized that [ 68 Ga]Ga-FAPI PET may be used as an indirect tracer for mapping hypoxia by correlating the image findings to pathological analysis of HIF-1α expression. The [ 68 Ga]Ga-FAPI PET/CT scans of women with cancer of the cervix were reviewed and the maximum and mean standardized uptake value (SUVmax and SUVmean) and FAPI tumor volume (FAPI-TV) were documented. Correlation analysis was performed between PET-derived parameters and immunohistochemical staining as well as between PET-derived parameters and the presence of metastasis. Ten women were included. All patients demonstrated tracer uptake in the primary site or region of the primary. All patients had lymph node metastases while only six patients had distant visceral or skeletal metastases. The mean SUVmax, SUVmean, and FAPI-TV was 18.89, 6.88, and 195.66 cm 3 , respectively. The average FAPI-TV for patients with additional sites of metastases was higher than those without. Immunohistochemistry revealed varying intensities of HIF-1α expression in all tested samples. There was a positive correlation between the presence of skeletal metastases and staining for HIF-1α (r=0.80;p=0.017). The presence of skeletal metastasis was correlated to the HIF-1⍺ staining (percentage distribution). Furthermore, the FAPI-TV was a better predictor of metastatic disease than the SUVmax.

225 Ac-PSMA-617, targeting the prostate-specific membrane antigen (PSMA), which is overexpressed on prostate cancer cells, has shown a remarkable therapeutic efficacy in heavily pretreated patients with metastatic castration-resistant prostate carcinoma (mCRPC). Here, we report on treatment outcome and survival using this novel treatment modality in a series of 53 patients with mCRPC directly after their androgen deprivation treatment (ADT). Methods: 225 Ac-PSMA-617 was administered to 53 such patients. 68 Ga-PSMA PET/CT was obtained at baseline, before every treatment cycle, and on follow-up to select patients for treatment, determine the activity to be administered, and assess their response. Serial prostate-specific antigen (PSA) measurements were obtained for response assessment. Results: The median age of the patients was 63.4 y (range, 45-83 y). In total, 167 cycles were administered (median, 3; range, 1-7). Forty-eight patients (91%) had a PSA decline of at least 50%, and 51 patients (96%) had any decline in PSA. 68 Ga-PSMA PET findings became negative in 30 patients. In the multivariate analysis, a PSA decline of at least 50% proved predictive of both progression-free survival (PFS) and overall survival (OS), and platelet count also proved predictive for PFS. The median estimated OS was 9 mo for patients with a PSA decline of less than 50% but was not yet reached at the latest follow-up (55 mo) for patients with a PSA decline of 50% or more. The estimated median PFS was 22 mo for patients with a PSA decline of at least 50% and 4 mo for patients with a PSA decline of less than 50%. No severe hematotoxicity was noted, and only 3 patients had grade III-IV nephrotoxicity. The commonest toxicity seen was grade I-II xerostomia, observed in 81% of patients. Conclusion: In 91% of 53 patients with mCRPC, treatment with 225 Ac-PSMA-617 immediately after ADT resulted in at least a 50% decrease in PSA level. Furthermore, a PSA decline of at least 50% proved the single most important factor predicting PFS and OS after 225 Ac-PSMA-617 treatment. Of interest, median OS in patients with a PSA decline of at least 50% was not yet reached at the latest follow-up (55 mo). These favorable results suggest that it would be of major clinical relevance to perform a prospective randomized study comparing 225 Ac-PSMA-617 with current standard-of-care treatment options such as enzalutamide, abiraterone acetate, and docetaxel after ADT., (© 2022 by the Society of Nuclear Medicine and Molecular Imaging.)

Purpose: Actinium-225-labeled prostate-specific membrane antigen ([ 225 Ac]Ac-PSMA-617) is safe and effective in the treatment of metastatic castration-resistant prostate cancer (mCRPC). No study has specifically assessed its safety in patients with extensive skeletal metastases of mCRPC. We aimed to investigate the hematologic toxicity and efficacy of [ 225 Ac]Ac-PSMA-617 therapy in patients with extensive skeletal metastases of mCRPC., Methods: We retrospectively reviewed the medical record of patients treated with [ 225 Ac]Ac-PSMA-617 for mCRPC. We included patients with a superscan pattern of skeletal metastases and those with 20 or more multifocal sites of skeletal metastases on baseline [ 68  Ga]Ga-PSMA-11 PET/CT. We reviewed the levels of hemoglobin, white blood cell (WBC), and platelet prior to each cycle of treatment and determined the presence of impaired bone marrow function at baseline and the grade of toxicity in the hematologic parameters induced by treatment. We evaluated the predictors of hematologic toxicity using binary logistic regression analysis. We also determined the presence of renal dysfunction before or during treatment. We assessed response to treatment using prostate-specific antigen response and the progression-free survival (PFS) and overall survival (OS)., Results: A total of 106 patients were included. Skeletal metastasis was in the superscan pattern in 34 patients (32.1%) and multifocal in 72 patients (67.9%). The median treatment cycle was 4 (range = 1-9). Ninety-eight patients (92.5%) had abnormal baseline hematologic parameters. One patient had grade 4 thrombocytopenia. Grade 3 anemia, leukopenia, and thrombocytopenia were seen in 1 (0.9%), 3 (2.8%), and 2 (1.9%) patients, respectively. Age, the number of treatment cycles, and the presence of renal dysfunction were significant predictors of hematologic toxicity. Eighty-five patients (80.2%) achieved PSA response. The median PFS and OS of the study population were 14:00 (95%CI: 8.15-19.86) months and 15.0 (95%CI: 12.8-17.2) months, respectively., Conclusions: [ 225 Ac]Ac-PSMA-617 induces a good anti-tumor effect in about 80% of patients with extensive skeletal metastases of mCRPC with a rare incidence of severe hematologic toxicity. Age, number of treatment cycles, and the presence of renal dysfunction were significant risk factors for hematologic toxicity of [ 225 Ac]Ac-PSMA-617 therapy., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: This study aimed to determine the correlation of [ 68 Ga]Ga-NODAGA ZOL uptake in atherosclerotic plaques and the cardiovascular risk profile of patients imaged with positron emission tomography (PET), wherein quantification of uptake was determined by atherosclerotic plaque maximum target-to-background ratio (TBRmax). We also correlated uptake with a history of cardiovascular events., Methods: We included patients who underwent PET/CT imaging post-injection of [ 68 Ga] Ga-NODAGA ZOL . We documented the number of atherosclerotic plaques found in the major arteries on CT and the cardiovascular risks in each patient. We quantified the intensity of tracer uptake in atherosclerotic plaque in the major arteries using the maximum standardized uptake value (SUVmax). The SUVmax of the most tracer-avid plaque was documented as representative of the individual arterial bed. We determined background vascular tracer activity using the mean standardized uptake value (SUVmean) obtained from the lumen of the superior vena cava. The maximum target-to-background ratio (TBRmax) was calculated as a ratio of the SUVmax to the SUVmean. The TBRmax was correlated to the number of atherogenic risk factors and history of cardiovascular events., Results: Thirty-four patients (M: F 31:3; mean age ± SD: 63 ± 10.01 years) with ≥ 2 cardiovascular risk factors were included. Statistically significant correlation between TBRmax and the number of cardiovascular risk factors was noted in the right carotid (r = 0.50; p < 0.05); left carotid (r = 0. 649; p < 0.05); ascending aorta (r = 0.375; p < 0.05); aortic arch (r = 0.483; p < 0.05); thoracic aorta (r = 0.644; p < 0.05); left femoral (r = 0.552; p < 0.05) and right femoral arteries (r = 0.533; p < 0.05). TBRmax also demonstrated a positive correlation to history of cardiovascular event in the right carotid (U = 26.00; p < 0.05); left carotid (U = 11.00; p < 0.05); ascending aorta (U = 49.00; p < 0.05); aortic arch (U = 37.00; p < 0.05); thoracic aorta (U = 16.00; p < 0.05); left common iliac (U = 49.500; p < 0.05), right common iliac (U = 43.00; p < 0.05), left femoral (U = 40.500; p < 0.05) and right femoral (U = 37.500; p < 0.05)., Conclusion: In this cohort of patients, a positive correlation was noted between atherosclerotic plaque uptake of [ 68 Ga]Ga-NODAGA ZOL and the number of atherogenic risk factors which translates to the risk of atherosclerosis and cardiovascular risk factors., (© 2022. The Author(s) under exclusive licence to The Japanese Society of Nuclear Medicine.)

Hypoxia in cervical cancer has been associated with a poor prognosis. Over the years 68 Ga labelled nitroimidazoles have been studied and have shown improved kinetics. We present our initial experience of hypoxia Positron Emission Tomography (PET) imaging in cervical cancer with 68 Ga-Nitroimidazole derivative and the correlation with 18 F-FDG PET/CT and immunohistochemistry. Twenty women with cervical cancer underwent both 18 F-FDG and 68 Ga-Nitroimidazole PET/CT imaging. Dual-point imaging was performed for 68 Ga-Nitroimidazole PET. Immunohistochemical analysis was performed with hypoxia inducible factor-1α (HIF-1α). We documented SUVmax, SUVmean of the primary lesions as well as tumor to muscle ratio (TMR), tumor to blood (TBR), metabolic tumor volume (MTV) and hypoxic tumor volume (HTV). There was no significant difference in the uptake of 68 Ga-Nitroimidazole between early and delayed imaging. Twelve patients had uptake on 68 Ga-Nitroimidazole PET. Ten patients demonstrated varying intensities of HIF-1α expression and six of these also had uptake on 68 Ga-Nitroimidazole PET. We found a strong negative correlation between HTV and immunohistochemical staining (r = -0.660; p = 0.019). There was no correlation between uptake on PET imaging and immunohistochemical analysis with HIF-1α. Two-thirds of the patients demonstrated hypoxia on 68 Ga-Nitroimidazole PET imaging.

Purpose: Prostate cancer (PCa) commonly metastasizes to the bones. There are several radionuclide techniques for imaging PCa skeletal metastases. We aimed to compare the lesion detection rate of [ 68 Ga]Ga-PSMA-11 PET/CT, [ 68 Ga]Ga-NODAGA-zoledronate ([ 68 Ga]Ga-NODAGA ZOL ) PET/CT, and [ 99m Tc]Tc-MDP bone scan in the assessment of bone metastases in patients with advanced PCa., Methods: We prospectively recruited two cohorts of patients (staging and re-staging cohorts) with advanced prostate cancer. The staging cohort was treatment-naïve PCa patients who showed skeletal metastases on bone scan. These patients were subsequently imaged with [ 68 Ga]Ga-PSMA-11 PET/CT and [ 68 Ga]Ga-NODAGA ZOL PET/CT. Re-staging cohort was patients who were previously treated with PSMA-based radioligand therapy and were experiencing PSA progression. The re-staging cohort was imaged with [ 68 Ga]Ga-PSMA-11 PET/CT and [ 68 Ga]Ga-NODAGA ZOL PET/CT. We performed a per-patient and per-lesion analysis of skeletal metastases in both cohorts and made a comparison between scan findings., Results: Eighteen patients were included with a median age of 68 years (range = 48-80) and a median Gleason score of 8. There were ten patients in the staging cohort with a median PSA of 119.26 ng/mL (range = 4.63-18,948.00) and eight patients in the re-staging cohort with a median PSA of 48.56 ng/mL (range = 6.51-3175.00). In the staging cohort, skeletal metastases detected by [ 68 Ga]Ga-PSMA-11 PET/CT, [ 68 Ga]Ga-NODAGA ZOL PET/CT, and bone scan were 322, 288, and 261, respectively, p = 0.578. In the re-staging cohort, [ 68 Ga]Ga-PSMA-11 PET/CT and [ 68 Ga]Ga-NODAGA ZOL PET/CT detected 152 and 191 skeletal metastases, respectively, p = 0.529. In two patients with negative [ 68 Ga]Ga-PSMA-11 PET/CT findings, [ 68 Ga]Ga-NODAGA ZOL detected one skeletal metastasis in one patient and 12 skeletal metastases in the other., Conclusion: In patients with advanced prostate cancer, [ 68 Ga]Ga-PSMA-11 PET/CT may detect more lesions than [ 68 Ga]Ga-NODAGA ZOL PET/CT and [ 99m Tc]Tc-MDP bone scan for the staging of skeletal metastases. In patients who experience PSA progression on PSMA-based radioligand therapy, [ 68 Ga]Ga-NODAGA PET/CT is a more suitable imaging modality for the detection of skeletal lesions not expressing PSMA. In the setting of re-staging, [ 68 Ga]Ga-NODAGA ZOL PET/CT may detect more lesions than [ 68 Ga]Ga-PSMA-11 PET/CT.

People living with human immunodeficiency virus (PLHIV) have excess risk of atherosclerotic cardiovascular disease (ASCVD). Arterial inflammation is the hallmark of atherogenesis and its complications. In this study we aimed to perform a head-to-head comparison of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography ([ 18 F]FDG PET/CT) and Gallium-68 pentixafor positron emission tomography/computed tomography [ 68 Ga]Ga-pentixafor PET/CT for quantification of arterial inflammation in PLHIV. We prospectively recruited human immunodeficiency virus (HIV)-infected patients to undergo [ 18 F]FDG PET/CT and [ 68 Ga]Ga-pentixafor PET/CT within two weeks of each other. We quantified the levels of arterial tracer uptake on both scans using maximum standardized uptake value (SUVmax) and target-background ratio. We used Bland and Altman plots to measure the level of agreement between tracer quantification parameters obtained on both scans. A total of 12 patients were included with a mean age of 44.67 ± 7.62 years. The mean duration of HIV infection and mean CD+ T-cell count of the study population were 71.08 ± 37 months and 522.17 ± 260.33 cells/µL, respectively. We found a high level of agreement in the quantification variables obtained using [ 18 F]FDG PET and [ 68 Ga]Ga-pentixafor PET. There is a good level of agreement in the arterial tracer quantification variables obtained using [ 18 F]FDG PET/CT and [ 68 Ga]Ga-pentixafor PET/CT in PLHIV. This suggests that [ 68 Ga]Ga-pentixafor may be applied in the place of [ 18 F]FDG PET/CT for the quantification of arterial inflammation.

Metastatic prostate carcinoma overexpresses prostate-specific membrane antigen (PSMA), making this antigen a suitable target for radioligand therapy of the disease. Here we report on our experience with a series of 73 castration-resistant prostate carcinoma patients treated with 225 Ac-PSMA-617, identifying variables predictive for overall survival (OS) and progression-free survival (PFS) after 225 Ac-PSMA-617 treatment. Methods: 225 Ac-PSMA-617 was administered to patients who had metastatic castration-resistant prostate carcinoma and who had exhausted available therapy options for their disease. Full blood count, glomerular filtration rate, and liver function test were obtained at baseline and on follow-up for evaluation of toxicity. 68 Ga-PSMA PET/CT was obtained at baseline, before every treatment cycle, and on follow-up for selection of patients for treatment, to determine the activity of the treatment agent to be administered, and for response assessment. Serial prostate-specific antigen (PSA) was obtained for PSA response assessment. Results: Seventy-three men (mean age, 69 y; range, 45-85 y) with metastatic castration-resistant prostate carcinoma were treated with 210 cycles of 225 Ac-PSMA-617. In 70% of patients, a PSA decline of greater than or equal to 50% was obtained; 82% of patients had any PSA decline. In 29% of patients, all lesions on 68 Ga-PSMA PET resolved in response to treatment. During follow-up, 23 patients experienced disease progression, whereas 13 patients died from their disease. The estimated median PFS and OS were 15.2 mo (95% CI, 13.1-17.4) and 18 mo (95% CI, 16.2-19.9), respectively. In univariate analyses, factors such as baseline PSA, any PSA decline, PSA decline of greater than or equal to 50%, prior chemotherapy, prior radiation therapy, and baseline hemoglobin level were associated with longer PFS and OS (all P s < 0.05). In multivariate analyses, there was a negative association between prior 177 Lu-PSMA therapy and PFS, and a positive association between PSA decline of greater or equal to 50% and PFS. Only a PSA decline of greater than or equal to 50% remained significantly associated with OS on multivariate analyses. Xerostomia was seen in 85% of patients but was not severe enough to warrant discontinuing treatment. Anemia was seen in 27 patients; no patients had grade IV bone marrow toxicity. Renal failure of grade III or IV was seen in 5 patients with baseline renal impairment. Conclusion: In this study, a PSA decline of greater than or equal to 50% after treatment with 225 Ac-PSMA-617 was proven by multivariate analyses to be significantly associated with OS and PFS. Furthermore, previous 177 Lu-PSMA treatment was negatively associated with PFS in both univariate and multivariate analyses., (© 2020 by the Society of Nuclear Medicine and Molecular Imaging.)

Background: A remarkable therapeutic efficacy has been demonstrated with 225 Ac-prostate-specific membrane antigen (PSMA)-617 in heavily pre-treated metastatic castration-resistant prostate cancer (mCRPC) patients. We report our experience with 225 Ac-PSMA-617 therapy in chemotherapy-naïve patients with advanced metastatic prostate carcinoma., Methods: Seventeen patients with advanced prostate cancer were selected for treatment with 225 Ac-PSMA-617 in 2-month intervals, with initial activity of 8 MBq, then de-escalation to 7 MBq, 6 MBq or 4 MBq in cases of good response. In one patient, activity was escalated to 13 MBq in the third cycle. Fourteen patients had three treatment cycles administered, while in three patients treatment was discontinued after two cycles due to good response. Six out of 17 patients received additional treatments after the third cycle. Prostate-specific antigen (PSA) was measured every 4 weeks for PSA response assessment. 68 Ga-PSMA-PET/CT was used for functional response assessment before each subsequent treatment cycle. Serial full blood count, renal function test, and liver function were obtained to determine treatment-related side effects., Results: Good antitumor activity assessed by serum PSA level and 68 Ga-PSMA-PET/CT was seen in 16/17 patients. In 14/17 patients, PSA decline ≥90% was seen after treatment, including seven patients with undetectable serum PSA following two (2/7) or three cycles (5/7) cycles of 225 Ac-PSMA-617. Fifteen of 17 patients had a > 50% decline in lesions avidity for tracer on 68 Ga-PSMA-PET/CT including 11 patients with complete resolution (PET-negative and either stable sclerosis on CT for bone or resolution of lymph node metastases) of all metastatic lesions. Grade 1/2 xerostomia was seen in all patients, and none was severe enough to lead to discontinuation of treatment. One patient had with extensive bone marrow metastases and a background anemia developed a grade 3 anemia while another patient with solitary kidney and pre-treatment grade 3 renal failure developed grade 4 renal toxicity following treatment. The group presented with significant palliation of bone pain and reduced toxicity to salivary glands due to de-escalation., Conclusions: 225 Ac-PSMA-617 RLT of chemotherapy-naïve patients with advanced metastatic prostate carcinoma led to a ≥ 90% decline in serum PSA in 82% of patients including 41% of patients with undetectable serum PSA who remained in remission 12 months after therapy. The remarkable therapeutic efficacy reported in this study could be achieved with reduced toxicity to salivary glands due to de-escalation of administered activities in subsequent treatment cycles. This necessitates further exploration for informing clinical practice and clinical trial design.