Considerations for intensity modulated total body or total marrow and lymphoid irradiation

We compiled a sampling of the treatment techniques of intensity-modulated total body irradiation, total marrow irradiation and total marrow and lymphoid irradiation utilized by several centers across North America and Europe. This manuscript does not serve as a consensus guideline, but rather is meant to serve as a convenient reference for centers that are considering starting an intensity-modulated program.

Total marrow irradiation (TMI): Addressing an unmet need in hematopoietic cell transplantation - a single institution experience review

Purpose

TMI utilizes IMRT to deliver organ sparing targeted radiotherapy in patients undergoing hematopoietic cell transplantation (HCT). TMI addresses an unmet need, specifically patients with refractory or relapsed (R/R) hematologic malignancies who have poor outcomes with standard HCT regimens and where attempts to improve outcomes by adding or dose escalating TBI are not possible due to increased toxicities. Over 500 patients have received TMI at this center. This review summarizes this experience including planning and delivery, clinical results, and future directions.

Methods

Patients were treated on prospective allogeneic HCT trials using helical tomographic or VMAT IMRT delivery. Target structures included the bone/marrow only (TMI), or the addition of lymph nodes, and spleen (total marrow and lymphoid irradiation, TMLI). Total dose ranged from 12 to 20 Gy at 1.5-2.0 Gy fractions twice daily.

Results

Trials demonstrate engraftment in all patients and a low incidence of radiation related toxicities and extramedullary relapses. In R/R acute leukemia TMLI 20 Gy, etoposide, and cyclophosphamide (Cy) results in a 1-year non-relapse mortality (NRM) rate of 6% and 2-year overall survival (OS) of 48%; TMLI 12 Gy added to fludarabine (flu) and melphalan (mel) in older patients (≥ 60 years old) results in a NRM rate of 33% comparable to flu/mel alone, and 5-year OS of 42%; and TMLI 20 Gy/flu/Cy and post-transplant Cy (PTCy) in haplo-identical HCT results in a 2-year NRM rate of 13% and 1-year OS of 83%. In AML in complete remission, TMLI 20 Gy and PTCy results in 2-year NRM, OS, and GVHD free/relapse-free survival (GRFS) rates of 0%, 86·7%, and 59.3%, respectively.

Conclusion

TMI/TMLI shows significant promise, low NRM rates, the ability to offer myeloablative radiation containing regimens to older patients, the ability to dose escalate, and response and survival rates that compare favorably to published results. Collaboration between radiation oncology and hematology is key to successful implementation. TMI/TMLI represents a paradigm shift from TBI towards novel strategies to integrate a safer and more effective target-specific radiation therapy into HCT conditioning beyond what is possible with TBI and will help expand and redefine the role of radiotherapy in HCT.

Target Coverage and Normal Organ Sparing in Dose-Escalated Total Marrow and Lymphatic Irradiation: A Single-Institution Experience

Purpose/Objectives

The aim of this study is to report historical treatment planning experience at our institution for patients receiving total marrow and lymphatic irradiation (TMLI) as part of the conditioning regimen prior to hematopoietic stem cell transplant.

Materials/Methods

Based on a review of all historical clinical TMLI treatments plans, we retrieved a 12-Gy cohort of 108 patients with a prescription dose of 12 Gy to the skeletal bones, lymph nodes, spleen, and spinal canal, and retrieved a 20-Gy cohort of 120 patients with an escalated prescription dose of 20 Gy to the skeletal bones, lymph nodes, spleen, and spinal cord, and 12 Gy to the brain and liver. Representative dosimetric parameters including mean and median dose, D80, and D10 (dose covering 80% and 10% of the structure volume, respectively) for targets and normal organs were extracted and compared between the two groups of patients.

Results

For the 12-Gy cohort, the average mean dose for normal organs ranged from 18.3% to 78.3% of 12 Gy, and the average median dose ranged from 18.3% to 77.5% of 12 Gy. For the 20-Gy cohort, the average mean dose for normal organs ranged from 13.0% to 76.0% of 20 Gy, and the average median dose ranged from 12.5% to 75.0% of 20 Gy. Compared to the mean dose to normal organs in the 12-Gy cohort, the average mean dose to normal organs increased from 0.0% to 73.1%, with only four normal organs showing a >50% increase. Normal organ dose in TMLI plans using volumetric modulated arc therapy fields fell within the dose range in historical TMLI plans.

Conclusion

Dosimetric data in historical TMLI plans at our institution are summarized at prescription dose levels of 12 Gy and 20 Gy, respectively. Compared to the normal organ dose with a prescription dose of 12 Gy, the mean and median dose to most normal organs at an escalated prescription dose of 20 Gy had an increase less than prescription dose scaling. Dosimetric results from this study can be used as reference data to facilitate clinical implementation of TMLI at other institutions.

Abstract 2732: A mathematical model for optimization of combination therapy involving targeted radionuclide and CAR-T cell therapy

Background: Immunotherapy with chimeric antigen receptor - T (CAR-T) cells and targeted radionuclide therapy (TRT) are two highly promising therapies in cancer treatment. Often, these therapies show limited efficacy in complete eradication of cancer cells making the combination of these two therapies an attractive cancer treatment option. The complications involved in dosing and scheduling of these therapies make mathematical modeling an appropriate method for analyzing and predicting disease response to these therapies. Here we propose a mathematical model evaluating disease response to the combination of these two therapies and explore the optimization of their dosing and scheduling.

Methods: An ordinary differential equation-based formalism is proposed for simulation of tumor response to CAR-T cell therapy as well as TRT. CAR-T cell dose and injected radioactivity was input to the model. Among others, key model parameters included tumor proliferation rate, tumor cell and CAR-T cell radiosensitivity, CAR-T cell killing rate, CAR-T cell decay rate indicating persistence. Preclinical experiments involving CS1- CAR-T cell therapy and 225Ac-DOTA-Daratumumab TRT in a multiple myeloma mice model were used to parameterize the model. Sensitivity study of the model parameters using overall survival (OS) and progression-free survival (PFS) as evaluation metrics, was performed to elucidate the parameters with highest impact.

Results: OS and PFS were 97 and 55 days when CAR-T cell therapy was given prior to TRT as compared to OS of 43 days for untreated control mice. Sensitivity study of model parameters showed that tumor proliferation has the highest impact on survival metrics. For a ±50% change in tumor proliferation rate, OS changed by -41%/+111% and PFS changed by -62%/+147%. Similar changes in TRT injected activity and CAR-T cell dose changed OS by ± 15% and ±21% respectively. Accordingly, PFS changed by roughly ±32% and ±45% respectively. A variation of the interval between the therapies showed that faster growing tumors required a shorter interval between the two therapies. The sequence of therapies was also changed and TRT prior to CAR-T cell therapy demonstrated shorter PFS (43 days) due to the adverse effects of radiation on CAR-T cells.

Conclusion: For a fixed dose of TRT and CAR-T cells, tumor proliferation rate was found to be the prime factor impacting therapy interval. The presented work shows the key parameters required for planning and optimizing preclinical experiments and clinical trials. Using disease, CAR-T cell and radionuclide-specific parameters as shown in this work as well as incorporating immune stimulating effects of radiation would make it an extremely potent tool for optimizing combination therapies.

Citation Format: Vikram Adhikarla, Dennis Awuah, Alexander B. Brummer, Enrico Caserta, Amrita Krishnan, Flavia Pichiorri, Megan M. Minnix, John E. Shively, Jeffrey Y.C. Wong, Xiuli Wang, Russell C. Rockne. A mathematical model for optimization of combination therapy involving targeted radionuclide and CAR-T cell therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2732.

Phase 1 study of JNJ-69086420, an actinium-225-labeled antibody targeting human kallikrein-2, for advanced prostate cancer

TPS5104

Background: Radioligand therapy for metastatic castration resistant prostate cancer (mCRPC) has been shown to prolong survival, delay disease progression, and improve quality of life, raising hopes that these gains will be amplified with even more cancer-specific targets and more powerful radioligands. Human kallikrein-related peptidase 2 (hK2) is a tumor-associated member of the kallikrein family that shares significant homology to prostate-specific antigen and is minimally expressed in normal non-prostate tissues. JNJ-69086420 (JNJ-420; 225Ac-DOTA-h11B6 [1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid]), is a first-in-class radioimmunotherapy targeted to hK2 antigen. In a phase 0 study of [111In]-DOTA-h11B6, patients with mCRPC (progressed on standard therapies), treatment with a single dose of [111In]-DOTA-h11B6 (2 mg) with/without 8 mg h11B6, demonstrated safety, good tumor localization, nominal normal-organ uptake, and no difference in pharmacokinetics (PK) between 2 and 10 mg antibody mass (Morris et al. J Clin Oncol. 2021 39:6 suppl, 122). We have initiated the first-in-human study to assess the safety, PK, pharmacodynamic (PD), and clinical activity of Ac-225 radiolabeled JNJ-420, to determine its recommended phase 2 dose (RP2D) in adults with advanced PC. Methods: This open-label, multicenter, phase 1 study will recruit approximately 50 men (aged ≥18 years) with advanced PC across dose escalation (Part 1) and expansion (Part 2) parts. Key eligibility criteria: mCRPC with histologic confirmation of adenocarcinoma, Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, adequate organ function based on hematology and serum chemistry, and 1 or more prior novel androgen receptor-targeted therapies (prior chemotherapy acceptable). Key exclusion criteria: prior treatment with radium/strontium/samarium/radioconjugate therapy, superscan findings as protocol defined, active central nervous system metastases. In Part 1, men will receive intravenous (IV) injection of 50 μCi/ 2 mg JNJ-420 (once every 8 weeks) with one or multiple doses; escalation of dose levels to be based on dose limiting toxicities (DLTs) evaluation, until RP2D identification. In Part 2, JNJ-420 is to be given at one of the RP2D(s) determined in Part 1. Primary endpoint is safety (incidence and severity [grading per NCI-CTCAE V5.0] of AEs including DLTs). Secondary endpoints include prostate specific antigen response rate, overall response rate (PCWG3 modified RECIST 1.1 criteria), PK, PD, immunogenicity, and biomarker analyses. Enrollment began in Dec 2020; as of 10 Feb 2022, 4 sites have been initiated and 23 patients enrolled; currently, dose escalation is ongoing. Clinical trial information: NCT04644770.

Phase 1 study of JNJ-69086420, an actinium-225-labeled antibody targeting human kallikrein-2, for advanced prostate cancer

TPS206

Background: Radioligand therapy for metastatic castration resistant prostate cancer (mCRPC) has been shown to prolong survival, delay disease progression, and improve quality of life, raising hopes that these gains will be amplified with even more cancer-specific targets and more powerful radioligands. Human kallikrein-related peptidase 2 (hK2) is a tumor-associated member of the kallikrein family that shares significant homology to prostate-specific antigen and is minimally expressed in normal non-prostate tissues. JNJ-69086420 (JNJ-420; 225Ac-DOTA-h11B6 [1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid]), is a first-in-class radioimmunotherapy targeted to hK2 antigen. In a phase 0 study of [111In]-DOTA-h11B6, patients (pts) with mCRPC (progressed on standard therapies), treatment with a single dose of [111In]-DOTA-h11B6 (2 mg) with/without 8 mg h11B6, demonstrated safety, good tumor localization, nominal normal-organ uptake, and no difference in PK between 2 and 10 mg antibody mass (Morris et al. J Clin Oncol. 2021 39:6 suppl, 122). We have initiated the first-in-human study to assess the safety, pharmacokinetics (PK), pharmacodynamic (PD), and clinical activity of Ac-225 radiolabeled JNJ-420, to determine its recommended phase 2 dose (RP2D) in adults with advanced PC. Methods: This open-label, multicenter, phase 1 study will recruit approximately 50 men (aged ≥18 years) with advanced PC across dose escalation (Part 1) and expansion (Part 2) parts. Key eligibility criteria: mCRPC with histologic confirmation of adenocarcinoma, Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, adequate organ function based on hematology and serum chemistry, and 1 or more prior novel androgen receptor-targeted therapies (prior chemotherapy acceptable). Key exclusion criteria: prior treatment with radium/strontium/samarium/radioconjugate therapy, superscan findings as protocol defined, active central nervous system metastases. In Part 1, men will receive intravenous (IV) injection of 50 μCi/ 2 mg JNJ-420 (once every 8 weeks) with one or multiple doses; escalation of dose levels to be based on dose limiting toxicities (DLTs) evaluation, until RP2D identification. In Part 2, JNJ-420 is to be given at one of the RP2D(s) determined in Part 1. Primary endpoint is safety (incidence and severity [grading per NCI-CTCAE V5.0] of AEs including DLTs). Secondary endpoints include prostate specific antigen response rate, overall response rate (PCWG3 modified RECIST 1.1 criteria), PK, PD, immunogenicity, and biomarker analyses. Enrollment began in Dec 2020; as of Sep 2021, 4 sites have been initiated and 14 pts enrolled; currently, dose escalation is ongoing. Clinical trial information: NCT04644770.

PSMA-targeted imaging with 18F-DCFPyL-PET/CT in patients (pts) withbiochemically recurrent prostate cancer (PCa): A phase 3 study (CONDOR)—A subanalysis of correct localization rate (CLR) and positive predictive value (PPV) by standard of truth

5023

Background: PSMA-targeted PET/CT is superior to conventional imaging modalities to localize biochemically recurrent (BCR) PCa after local therapy, particularly in pts with low PSA ( < 2 ng/mL). However, few studies have reported PSMA-targeted PET/CT accuracy compared to a pre-specified rigorous standard of truth (SOT) including histopathology, correlative imaging or treatment response in this population. Here, we report the CLR and PPV of PSMA-targeted 18F-DCFPyLPET/ CT, for each of the pre-defined SOT criteria for the CONDOR prospective phase 3 study. Methods: The study enrolled men with rising PSA after definitive therapy and negative or equivocal standard of care imaging (e.g., CT/MRI, bone scintigraphy, F-18 fluciclovine). A single 9 mCi (333 MBq) ± 20% dose of 18F-DCFPyL was injected, followed by PET/CT 1-2 hours later. Pts with positive 18F-DCFPyL-PET/CT scans based on local interpretation were scheduled for follow up within 60 days to verify suspected lesion(s) using a composite SOT. The primary endpoint was CLR defined as PPV with the requirement of anatomic lesion co-localization between 18F-DCFPyL-PET/CT and the SOT. The SOT consisted of, in descending priority: 1) histopathology, 2) subsequent correlative imaging findings determined by twocentral readers, or 3) post-radiation PSA response. The trial was successful if the lower bound of the 95% confidence interval for CLR exceeded 20% for at least two of three independent, blinded central 18F-DCFPyL-PET/CT reviewers. Results: 208 men (median PSA 0.8 ng/mL) underwent 18F-DCFPyL-PET/CT and the study achieved its primary endpoint: CLR was between 84.8% to 87.0% (lower bound of 95% CI: 77.8%-80.4%) among the three 18F-DCFPyL-PET/CT readers, against the composite SOT. The performance of 18F-DCFPyL-PET/CT by CLR (≥1 lesion co-localized) and PPV (≥1 lesion confirmed) was maintained through all 3 SOT categories. Histopathology (N = 31): 78.6-82.8% and 92.9-93.3% for CLR and PPV, respectively; correlative imaging (N = 100): 86.1-88.6% and 87.0-89.5% for CLR and PPV, respectively; and PSA response (N = 1): 100% for both CLR and PPV. Further analyses of the correlative imaging results showed CLR remained high across the different modalities used a) 18F-fluciclovine-PET/CT (N = 71): (86.8-90.9%); b) MRI (N = 23): (80.0-86.7%); and c) CT (n = 6): (80.0-100%). Conclusions: PSMA-targeted 18F-DCFPyL-PET/CT detected and localized metastatic lesions with high CLR and PPV regardless of which criterion defined CLR that was used, in men with BCR who had negative or equivocal baseline imaging. Clinicaltrials.gov: NCT03739684 Clinical trial information: NCT03739684.

Radiation and androgen deprivation therapy with or without docetaxel in the management of non-metastatic unfavorable-risk prostate cancer: A prospective randomized trial

5011

Background: For men with unfavorable-risk non-metastatic (M0) prostate cancer (PC) the addition of docetaxel to radical prostatectomy (RP) or radiation therapy (RT) and androgen deprivation therapy (ADT) has been studied in 6 randomized controlled trials with negative or inconclusive results. Specifically, an overall survival (OS) benefit with a non-significant reduction in PC-specific mortality (PCSM) has been observed in two of the 6 studieswhere > 80% of the patients had high-grade PC. A plausible hypothesis for the OS benefit and a non-significant reduction in PCSM is that docetaxel reduces PCSM in the small subset of men with low prostate-specific antigen (PSA)-producing, high-grade PC that may be resistant to conventional ADT while also reducing non-PCSM by reducing death from RT-induced cancers. Given that docetaxel even at low doses (i.e. 20 mg/m2) is a potent radiosensitizer,it is plausible that it can sterilize cells that survive RT-induced damage and later develop into RT-induced cancers. Therefore, while docetaxel is not recommended when managing men with unfavorable-risk prostate cancer given inconclusive results from prior randomized trials, unstudied benefits may exist. Methods: This multicenter international randomized phase 3 trial (National Clinical Trial # 00116142) assigned 350 men with T1c-4N0M0 unfavorable-risk PC to receive ADT+RT and Docetaxel (60 mg/m2 q3 weeks for 3 cycles before RT and 20 mg/m2 weekly during RT) versus ADT+RT (1:1 ratio). Collection of data at each follow-up visit on second cancer incidence and survival status was recorded. We evaluated the treatment effect of adding docetaxel to ADT+RT on the primary endpoint of OS and the incidence of RT-induced cancers and explored whether the treatment effect impacted OS differed differently within PSA subgroups ( < 4, > 20 versus 4-20 ng/mL) using the interaction test for heterogeneity adjusted for age and known PC prognostic factors. Results: After a median follow-up of 10.2 years, 89 men died (25.43%); of these 42 from PC (47.19%). While OS was not significantly increased on the docetaxel arm [restricted mean survival time over 10-years was 9.11 versus 8.82 years with a difference of 0.29 (95% CI: -0.19, 0.76) years (p = 0.22)], significantly fewer RT-induced cancers were observed [10-year estimates: 0.61% versus 4.90%: age-adjusted HR of 0.13: 95% CI: 0.02, 0.97; p = 0.046]. For men with a PSA < 4 ng/mL versus 4-20 ng/mL the treatment effect of adding docetaxel to ADT+RT on OS differed significantly [Adjusted HR: 0.27, 1.51; pinteraction = 0.047] due to less PCSM on the docetaxel arm [0/13 (0.00%) versus 4/14 (28.57%)] among men with PSA < 4 ng/mL. Conclusions: Adding docetaxel to ADT+RT did not prolong OS in men with unfavorable-risk PC, but decreased RT-induced cancer incidence, and may prolong OS in the subgroup of men with a PSA < 4 ng/mL by reducing PCSM. Clinical trial information: NCT00116142.

A tail's tale: Biomechanical roles of dorsal thoracic spine of barnacle nauplii

Many marine invertebrates have complex life histories that begin with a planktonic larval stage. Similar to other plankton, these larval invertebrates often possess protruding body extensions, but their function beyond predator deterrence is not well-documented. For example, the planktonic nauplii of crustaceans have spines. Using the epibiotic pedunculate barnacle Octolasmis spp., we investigated how the dorsal thoracic spine affects swimming and fluid disturbance by comparing nauplii with their spines partially removed against those with intact spines. Our motion analysis showed that amputated Octolasmis spp. swam slower, in jerkier trajectories, and were less efficient per stroke cycle than those with intact spines. Amputees showed alterations in limb beat pattern: larger beat amplitude, increased phase lag, and reduced contralateral symmetry. These changes might partially help increase propulsive force generation and streamline the flow, but were insufficient to restore full function. Particle image velocimetry further showed that amputees had a larger relative area of influence, implying elevated risk by rheotactic predator. Body extensions and their interactions with limb motion play important biomechanical roles in shaping larval performance, which likely influences the evolution of form.

PSMA-targeted imaging with 18F-DCFPyL-PET/CT in patients (pts) with biochemically recurrent prostate cancer (PCa): A phase III study (CONDOR)—A subanalysis of correct localization rate (CLR) and positive predictive value (PPV) by standard of truth

33

Background: PSMA-targeted PET/CT is superior to conventional imaging modalities to localize biochemically recurrent (BCR) PCa after local therapy, particularly in pts with low PSA (<2 ng/mL). However, few studies have reported PSMA-targeted PET/CT accuracy compared to a pre-specified rigorous standard of truth (SOT) including histopathology, correlative imaging or treatment response in this population. Here, we report the CLR and PPV of PSMA-targeted 18F-DCFPyL-PET/CT, for each of the pre-defined SOT criteria for the CONDOR prospective phase 3 study. Methods: The study enrolled men with rising PSA after definitive therapy and negative or equivocal standard of care imaging (e.g., CT/MRI, bone scintigraphy, F-18 fluciclovine). A single 9 mCi (333 MBq) ± 20% dose of 18F-DCFPyL was injected, followed by PET/CT 1-2 hours later. Pts with positive 18F-DCFPyL-PET/CT scans based on local interpretation were scheduled for follow up within 60 days to verify suspected lesion(s) using a composite SOT. The primary endpoint was CLR defined as PPV with the requirement of anatomic lesion co-localization between 18F-DCFPyL-PET/CT and the SOT. The SOT consisted of, in descending priority: 1) histopathology, 2) subsequent correlative imaging findings determined by two central readers, or 3) post-radiation PSA response. The trial was successful if the lower bound of the 95% confidence interval for CLR exceeded 20% for at least two of three independent, blinded central 18F-DCFPyL-PET/CT reviewers. Results: 208 men (median PSA 0.8 ng/mL) underwent 18F-DCFPyL-PET/CT and the study achieved its primary endpoint: CLR was between 84.8% to 87.0% (lower bound of 95% CI: 77.8%-80.4%) among the three 18F-DCFPyL-PET/CT readers, against the composite SOT. The performance of 18F-DCFPyL-PET/CT by CLR (≥1 lesion co-localized) and PPV (≥1 lesion confirmed) was maintained through all 3 SOT categories. Histopathology (N=31): 78.6-82.8% and 92.9-93.3% for CLR and PPV, respectively; correlative imaging (N=100): 86.1-88.6% and 87.0-89.5% for CLR and PPV, respectively; and PSA response (N=1): 100% for both CLR and PPV. Further analyses of the correlative imaging results showed CLR remained high across the different modalities used a) 18F-fluciclovine-PET/CT (N=71): (86.8-90.9%); b) MRI (N=23): (80.0-86.7%); and c) CT (n=6): (80.0-100%). Conclusions: PSMA-targeted 18F-DCFPyL-PET/CT detected and localized metastatic lesions with high CLR and PPV regardless of which criterion defined CLR that was used, in men with BCR who had negative or equivocal baseline imaging. Clinical trial information: NCT03739684.

Impact of PSMA-targeted imaging with 18F-DCFPyL-PET/CT on clinical management of patients (pts) with biochemically recurrent (BCR) prostate cancer (PCa): Results from a phase III, prospective, multicenter study (CONDOR)

5501

Background: Current imaging modalities are inadequate for localizing and characterizing occult disease in men with BCR PCa, particularly in pts with low PSAs (<2 ng/mL). There is a need for improved diagnostic imaging to better inform treatment planning. 18F-DCFPyL (PyL) is a novel PET imaging agent that binds selectively with high affinity to PSMA, which is overexpressed in PCa cells. Methods: Men ≥18 years- with rising PSA after definitive therapy and negative or equivocal standard of care imaging (e.g., CT/MRI, bone scintigraphy) were enrolled. A single 9 mCi (333 MBq) ± 20% dose of PyL was injected, followed by PET/CT 1-2 hours later. Primary endpoint was correct localization rate (CLR), defined as percentage of pts with a 1:1 correspondence between at least one lesion identified by PyL-PET/CT and the composite standard of truth: pathology, correlative imaging, or PSA response. The trial was successful if the lower bound of the 95% confidence interval (LLCI) for CLR exceeded 20% for two of three independent, blinded central PyL-PET/CT reviewers. The secondary endpoint, impact of PyL-PET/CT on clinical management of pts was based on the treating physician’s documented clinical plans before and after PyL-PET/CT. Results: 208 men (median PSA 0.8 [0.2 - 98.4] ng/mL) underwent PyL PET/CT. The study achieved its primary endpoint: CLR of 84.8% to 87.0% among the three PyL-PET/CT readers; the LLCI for CLR by all three reviewers was >77%. Here we report the clinical impact. Based on local radiology assessment, PSMA-avid lesion(s) were identified in 69.3% (142/208) of pts. 63.9% (131/205) had a change in intended management after PyL-PET/CT, of which 78.6% (103/131) were attributable to positive PyL finding(s) and 21.4% (28/131) to negative PyL scans. Changes included: salvage local therapy to systemic therapy (n=58); observation before initiating therapy (n=49); noncurative systemic therapy to salvage local therapy (n=43); and planned treatment to observation (n=9). PyL was well tolerated with one drug-related SAE (hypersensitivity) and the most common AE being headache (n=4; 1.9%). Conclusions: PSMA-targeted PyL-PET/CT detected and localized occult disease in most men with BCR presenting with negative or equivocal conventional imaging. PyL-PET/CT led to changed management plans in the majority of pts, thus providing evidence that clinicians find PSMA PET imaging useful in men with recurrent or suspected metastatic PCa. Clinical trial information: NCT03739684 .

Evolution of Feeding Shapes Swimming Kinematics of Barnacle Naupliar Larvae: A Comparison between Trophic Modes

A central goal in evolutionary biology is connecting morphological features with ecological functions. For marine invertebrate larvae, appendage movement determines locomotion, feeding, and predator avoidance ability. Barnacle larvae are morphologically diverse, and the morphology of non-feeding lecithotrophic nauplii are distinct from those that are planktotrophic. Lecithotrophic larvae have a more globular body shape and simplified appendages when compared with planktotrophs. However, little is known about whether and how such morphological changes affect kinematics, hydrodynamics, and ecological functions. Here, we compared the nauplii kinematics and hydrodynamics of a lecithotrophic Rhizocephalan species, Polyascus planus, against that of the planktotrophic nauplii of an intertidal barnacle, Tetraclita japonica. High-speed, micro-particle image velocimetry analysis showed that the Polyascus nauplii swam faster and had higher amplitude and more synchronous appendage beating than the Tetraclita nauplii. This fast swimming was accompanied by a faster attenuation of induced flow with distance, suggesting reduced predation risk. Tetraclita nauplii had more efficient per beat cycles with less backward displacement during the recovery stroke. This "anchoring effect" resulted from the anti-phase beating of appendages. This movement, together with a high-drag body form, likely helps direct the suction flow toward the ventral food capturing area. In sum, the tradeoff between swimming speed and predation risks may have been an important factor in the evolution of the observed larval forms.

Phase I Study of Yttrium-90 Radiolabeled M5A Anti-Carcinoembryonic Antigen Humanized Antibody in Patients with Advanced Carcinoembryonic Antigen Producing Malignancies

Background: M5A is a humanized monoclonal antibody (mAb) directed against carcinoembryonic antigen (CEA) The purpose of this first in human phase I dose-escalation trial was to characterize the toxicities and determine the maximum tolerated dose (MTD) of yttrium-90 (90Y)-DOTA-M5A as a single agent and in combination with gemcitabine (gem). Methods: Patients with advanced metastatic CEA-producing malignancies who had progressed on standard therapies were first administered indium-111 (111In)-DOTA-M5A. If tumor targeting was observed, the patient then received the therapy dose of 90Y-DOTA-M5A. Serial scans, blood sampling, and 24 h urine collections were then performed to estimate radiation doses to organs and total body. Assays for human antihuman antibody (HAHA) responses were performed out to 6 months. Results: Of the 18 patients who received 111In-DOTA-M5A, 16 received 90Y-DOTA-M5A therapy; 1 patient at 14 mCi/m2 with gem (150 mg/m2 days 1and 3), 3 patients at 12 mCi/m2 with gem, 6 patients at 12 mCi/m2 without gem, and 6 at 10 mCi/m2 without gem. Prolonged cytopenias resulted in discontinuation of dose escalation with gemcitabine. A single agent MTD of 10 mCi/m2 was established based on dose-limiting hematopoietic toxicities. HAHA immune response was identified in 2 of 16 patients (12.5%). Stable disease at 3 months was seen in 10 patients and 2 patients demonstrated an 88% and 64% decrease in CEA back to normal levels. In 2 patients 111In-DOTA-M5A imaging revealed previously unknown brain metastases. Conclusion: This study demonstrates the potential utility of the 90Y-DOTA-M5A anti-CEA mAb as a therapeutic antibody. There is decreased immunogenicity compared with murine and chimeric mAbs, allowing for the potential of multiple administrations. Combined modality therapy approaches incorporating this agent should continue to be evaluated.

A phase III, multicenter study to assess the diagnostic performance and clinical impact of 18F-DCFPyL PET/CT in men with suspected recurrence of prostate cancer (CONDOR)

TPS5093

Background: Early and accurate detection of recurrent or metastatic prostate cancer remains an unmet diagnostic need for patient management. While agents for positron emission tomography (PET), such as 11C-choline and 18F-fluciclovine, have emerged as options for imaging recurrent prostate cancer, these agents are not specific for the disease. 18F-DCFPyL is a novel, low-molecular weight, PET radiopharmaceutical that binds selectively to prostate-specific membrane antigen with high affinity. In prior studies, 18F-DCFPyL PET/CT has shown reliable diagnostic performance in detecting metastatic or recurrent prostate cancer (Rowe Mol Imaging Biol 2016 18:411-19; Gorin J Urol 2018 1999:126-32). Methods: CONDOR is a phase 3, multicenter, open-label study designed to assess the diagnostic performance and clinical impact of 18F-DCFPyL PET/CT in men with suspected recurrent or metastatic prostate cancer. Approximately 200 patients are planned to be enrolled across 15 centers in the United States and Canada. Eligible patients ≥18 years of age must have histologically confirmed prostate adenocarcinoma, have rising PSA after definitive therapy, and negative or equivocal conventional imaging. A single 9 mCi (333 MBq) dose of 18F-DCFPyL is administered, followed by whole body PET/CT scan 1 hour later. The primary objective is to assess the correct localization rate (percentage of patients with a one-to-one correspondence between localization of at least one lesion identified on 18F-DCFPyL PET/CT and the composite truth standard, defined as either evaluable histopathology, informative correlative imaging, or PSA response after radiation therapy). Additional study objectives include safety and tolerability of 18F-DCFPyL, impact on intended treatment plans, detection rates and PPV of 18F-DCFPyL by region, and detection rates by baseline PSA. 18F-DCFPyL PET/CT results are centrally reviewed by independent readers blinded to all clinical and other imaging information. As of February 9, 2019, a total of 36 patients have been dosed in the study. Clinical trial information: NCT03739684.

Seroprevalence of Leptospirosis in Working Dogs

Working dogs are canine animals that have been trained to assist human beings in carrying out various tasks. They help in guarding property, performing rescues, assisting the visually impaired or physically handicapped, searching for drugs, explosives, and others. Leptospirosis is one of the most widespread zoonotic diseases in the world and a commonly occurring disease of the tropics and subtropics. In Malaysia, all working dogs are normally vaccinated with serovars, Pomona, Icterohaemorrhagiae, Canicola, and Grippotyphosa based on protocols recommended from other countries. The duration of immunity in vaccinated dogs for Leptospira can last up to 13 months; however, there is no full crossprotection between the different serovars. Five representative canine units from different government agencies in Malaysia (n = 96 dogs) were recruited in this study. For detection, the microscopic agglutination test was performed by incubating the serum from dogs with various serovars of leptospires, namely, Icterohaemorrhagiae, Canicola, Pomona, Grippotyphosa, Australis, Bataviae, Javanica, Tarassovi, Hebdomadis, Lai, and Pyrogenes. The plasma obtained was used for polymerase chain reaction (PCR) analysis, for the detection of 16S rRNA, and lipL 32 genes of Leptospira. Out of the 96 dogs sampled, only 3 dogs were positive toward serovars, Australis, Bataviae, and Javanica, based on the cutoff point at 1:80. The seroprevalence of canine leptospirosis in this population was 3.1% (n = 3/96). However, all 96 blood samples of working dogs tested negative for both pathogenic and nonpathogenic Leptospira genes. The results revealed that, by vaccination alone, working dogs were not fully protected against leptospirosis and could pose a risk to dog handlers. A preventative and control protocol for leptospirosis is warranted, and its implementation should be monitored and improved accordingly from time to time, in order to maintain a healthy condition in both working dogs and their handlers.

Randomized phase II trial of sipuleucel-T immunotherapy preceded by sensitizing radiation therapy and sipuleucel-t alone in patients with metastatic castrate resistant prostate cancer

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Background: Sipuleucel-T (sip-T) is an autologous cellular vaccine indicated for patients (pts) with asymptomatic or minimally symptomatic metastatic castration resistant prostate cancer (mCRPC). Since radiation therapy (RT) can suppress the bone marrow function and immune response, previous studies evaluating sip-T excluded pts who received RT less than or equal to 28 days prior to sip-T therapy. Recent evidence suggests that RT may act synergistically with immunotherapy to enhance and broaden antitumor immune response. Methods: Pts who met standard criteria for sip-T were randomized to receive sip-T alone (Arm A) or sip-T initiated 1 week after completing sensitizing RT to single metastatic site (Arm B). RT was delivered at 300cGy/day to 3000 cGy total. The primary endpoint was the ability to safely combine sip-T preceded by RT and generate sip-T product with adequate immune activation parameters. Secondary endpoints included the measurement of immune responses to prostatic acid phosphatase (PAP) and PA20204 (recombinant fusion protein utilized in the generation of sip-T). Results: 51 pts were enrolled, 2 did not receive any sip-T because of vascular access problems and were excluded. 24 were treated on Arm A, 25 on Arm B. 47/49 pts received all 3 sip-T infusions. Median age was 66 yrs (range 45-90). Sip-T product parameters including: total nucleated cell (TNC) count, antigen presenting cell (APC) count and APC activation were similar in both groups. 2 pts on Arm A demonstrated PSA response. Median progression free survival (PFS) was 3.0 months on Arm A and 4.6 months on Arm B (p = 0.19). Both arms showed similar increases in humoral responses to PA2024 and PAP. IFN-ƴ ELISPOT T-cell activation responses to PA20204 were observed in both arms, but were more robust in the Arm A (p = 0.04). Both arms were well-tolerated, with fatigue as the most common grade 2 adverse event (1 pt in Arm A and 3 pts in Arm B). Conclusions: Sensitizing RT completed 1 week before generation of sip-T did not affect product parameters and the ability to deliver sip-T therapy. RT did not enhance the humoral and cellular responses associated with sip-T therapy. Clinical trial information: NCT01807065.

Effect of increasing radiation dose on pathologic complete response in rectal cancer patients treated with neoadjuvant chemoradiation therapy

BACKGROUND

Neoadjuvant chemoradiation therapy (CRT) increases pathological complete response (pCR) rates compared to radiotherapy alone in patients with stage II-III rectal cancer. Limited evidence addresses whether radiotherapy dose escalation further improves pCR rates. Our purpose is to measure the effects of radiotherapy dose and other factors on post-therapy pathologic tumor (ypT) and nodal stage in rectal cancer patients treated with neoadjuvant CRT followed by mesorectal excision.

MATERIAL AND METHODS

A non-randomized comparative effectiveness analysis was performed of rectal cancer patients treated in 2000-2013 from the National Oncology Data Alliance™ (NODA), a pooled database of cancer registries from >150 US hospitals. The NODA contains the same data submitted to state cancer registries and SEER combined with validated radiotherapy and chemotherapy records. Eligible patients were treated with neoadjuvant CRT followed by proctectomy and had complete data on treatment start dates, radiotherapy dose, clinical tumor (cT) and ypT stage, and number of positive nodes at surgery (n = 3298 patients). Multivariable logistic regression was used to assess the predictive value of independent variables on achieving a pCR.

RESULTS

On multivariable regression, radiotherapy dose, cT stage, and time interval between CRT and surgery were significant predictors of achieving a pCR. After adjusting for the effect of other variates, patients treated with higher radiotherapy doses were also more likely to have negative nodes at surgery and be downstaged from cT3-T4 and/or node positive disease to ypT0-T2N0 after neoadjuvant CRT.

CONCLUSION

Our study suggests that increasing dose significantly improved pCR rates and downstaging in rectal cancer patients treated with neoadjuvant CRT followed by surgery.

Automated otolith image classification with multiple views: an evaluation on Sciaenidae

Combined multiple 2D views (proximal, anterior and ventral aspects) of the sagittal otolith are proposed here as a method to capture shape information for fish classification. Classification performance of single view compared with combined 2D views show improved classification accuracy of the latter, for nine species of Sciaenidae. The effects of shape description methods (shape indices, Procrustes analysis and elliptical Fourier analysis) on classification performance were evaluated. Procrustes analysis and elliptical Fourier analysis perform better than shape indices when single view is considered, but all perform equally well with combined views. A generic content-based image retrieval (CBIR) system that ranks dissimilarity (Procrustes distance) of otolith images was built to search query images without the need for detailed information of side (left or right), aspect (proximal or distal) and direction (positive or negative) of the otolith. Methods for the development of this automated classification system are discussed.

Analysis of Surveillance, Epidemiology, and End Results Program (SEER) PSA coding error using primary data

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Background: SEER did not report PSA values for the 2014 submission because of inaccurate coding. This inaccuracy was a result of a confusing data entry guideline where PSA is coded in a 3-digit field with an implied decimal between digits 2 and 3. Our study uses original registry data to assess the magnitude and implications of these coding errors. Methods: The National Oncology Data Alliance is a database of more than 150 Commission-on-Cancer compliant tumor registries that use proprietary cancer registry software sold by Elekta AB (Stockholm, Sweden) and contains the same data sent to state tumor registries and SEER. De-identified data from all newly diagnosed prostate cancer cases from 2005-2013 were extracted (n = 89,379). PSA data were acquired from both the Collaborative Staging (CS) Site Specific Factor 1 (SSF1) for prostate cancer and from de-identified text fields. SSF1 contained the error prone datum that was transferred to SEER. The PSA data contained in the text fields, which are used to record lab results, etc. verbatim, were taken to be definitive. PSA values from both SSF1 and text fields were complete in 63,051 patients. AJCC Stage was determined using the clinical T stage field and the SSF fields that code for Gleason score. We calculated the error rates and their directions for PSA stratification into three levels (0 to < 10, 10 to < 20, and ≥ 20) and for the AJCC stage. Results: The measured error rate in PSA values in SSF1 caused by erroneous decimal placement was 9.0%. The resulting error rate in PSA stratification was 7.5%, with the SSF1 PSA value giving a higher PSA category in 4.8% of cases and lower in 2.7%. The consequent error rate in AJCC staging was 2.8% overall, with the PSA error resulting in a higher stage group in 1.9% and lower in 0.9%. Conclusions: Many factors can contribute to the overall error rate in PSA values in SEER data, but we are addressing only the errors associated with the implied decimal. The consequences of this error are modest despite a 9% error rate. However, SSF1 for prostate cancer is not the only confusing SSF introduced by the CS system. The current cancer registry database design is derived from outdated technology and needs restructuring to be a more effective surveillance and research tool.

Surface modification of uniaxial cyclic strain cell culture platform with temperature-responsive polymer for cell sheet detachment

Current cell sheet-based blood vessels lack biomimetic structure and require excessively long culture times that may compromise smooth muscle cell phenotype. We modified a commercially available product for uniaxial cell sheet conditioning with thermoresponsive copolymers. Thus, culture of detachable conditioned cell sheets is shortened while retaining structural integrity and contractility.

Increase in higher risk prostate cancer cases following new screening recommendation by the US Preventive Services Task Force (USPSTF)

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Background: In 2011, the USPSTF issued a draft recommendation that PSA not be used for prostate cancer screening in men irrespective of age. Here we present early measures of the potential consequences of this recommendation. Methods: Data on men diagnosed with prostate cancer from January, 2005 through June, 2013 were extracted from the National Oncology Data Alliance (Elekta/IMPAC Medical Systems, Inc., Sunnyvale, CA). This proprietary database of merged tumor registries captures newly diagnosed cancer cases at more than 150 hospitals in the United States. Data were available through 2013 compared to 2011 in Surveillance, Epidemiology, and End Results (SEER). The data in the NODA are identical to the data sent to state tumor registries and SEER in regions that participate in SEER. Date of diagnosis, age, race, T stage, Gleason score, and PSA were collected. Patients were classified into their respective National Comprehensive Cancer Network (NCCN) risk group. Data were available and analyzed for 87,562 men. Frequencies were examined by date of diagnosis, grouped in six-month intervals. Trends were assessed using linear regression. Results: From 2005 to 2011, the percentage of men with PSA>10 decreased gradually. From 2011 to 2013, the percentage increased by 3.0% per year (p<0.0004). The fraction of men with age ≥75 years to present with PSA>10 increased by nearly double the rate for men of all ages from 2011 to 2013. No significant trends in Gleason score were observed; the frequency of men with higher T stages generally decreased over the entire period without a notable change after 2011. The percentage of men with intermediate or higher risk cancer was stable at 70-73% prior to 2011, but rose by 2.9 % per year after 2011 (p<0.003) without evidence of a plateau. Conclusions: The proportion of men diagnosed with intermediate or higher risk cancer increased by nearly 6% from 2011 to 2013. Given an estimated 233,000 new prostate cancers in 2014, approximately 14,000 men per year will shift from low risk into a higher risk disease group. Our findings suggest an increase in the fraction of men diagnosed with higher risk prostate cancer after 2011.

Impact of total lymph node count on staging and survival after neoadjuvant chemoradiation therapy for rectal cancer

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Background: Neoadjuvant chemoradiation therapy (CRT) results in fewer retrieved lymph nodes at the time of surgery for rectal cancer. The extent of optimal regional nodal dissection is based on guidelines developed before neoadjuvant CRT was commonly used. The purpose of this study is to assess the impact of the number of dissected and positive lymph nodes on overall survival (OS) for rectal cancer patients treated with neoadjuvant CRT. Methods: Treatment data were obtained by structured query on all patients with rectal adenocarcinoma (2000-2013) in the National Oncology Data Alliance, a proprietary database of merged tumor registries. Eligible patients were treated with neoadjuvant CRT followed by surgery and had complete data on the number of positive and dissected lymph nodes and dates of treatment. The relationships between number of lymph nodes examined and OS were separately analyzed in patients with 0, exactly 1, or any number of positive nodes. Results: The median number of lymph nodes examined was 11 (interquartile range 6-16). In 4,581 evaluable patients, there was a significant improvement in OS with the examination of more lymph nodes. Number of positive lymph nodes, number of lymph nodes dissected, age, gender, grade, marital status, and race were significant predictors of OS on multivariate analysis. On subset analysis, patients with 0, exactly 1, and any number of positive nodes were found to have better OS with increasing number of lymph nodes dissected up to eight. Increasing overall mortality was observed in patients with 0, 1, 2-4, 5-7, and ≥8 positive lymph nodes. The Kaplan-Meier curves showed a clear statistically significant difference in OS in patients divided into these five nodal groupings (p<0.0001). Conclusions: Patients with eight or more lymph nodes examined had the greatest improvement in OS in rectal cancer patients treated with neoadjuvant CRT. This should be considered the threshold for an adequate lymph node sampling in this population. A five-tier nodal grouping was found to best forecast prognosis based on the number of positive lymph nodes identified.

Successful lung transplant in a child with cystic fibrosis and persistent Blastobotrys rhaffinosifermentans infection

Fungal respiratory infections in patients with CF are a significant concern both pre- and post-lung transplantation (LTx). Fungal infection is associated with increased mortality post-LTx, and in the past decade, the prevalence of fungal colonization in Canadian pediatric patients with CF has increased. The emergence of novel fungal pathogens is particularly challenging to the transplant community, as little is known regarding their virulence and optimal management. We present a case of a successful double-lung transplant in a pediatric patient with CF who was infected pretransplantation with a novel yeast, Blastobotrys rhaffinosifermentans. This patient was treated successfully with aggressive antifungal therapy post-transplantation, followed by extended fungal prophylaxis. The significance of fungal colonization and infection in children with CF pre- and post-LTx is reviewed.

Preliminary inferences on the age-specific seriousness of human disease caused by avian influenza A(H7N9) infections in China, March to April 2013

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Preliminary inferences on the age-specific seriousness of human disease caused by avian influenza A(H7N9) infections in China, March to April 2013

Between 31 March and 21 April 2013, 102 laboratory-confirmed influenza A(H7N9) infections have been reported in six provinces of China. Using survey data on age-specific rates of exposure to live poultry in China, we estimated that risk of serious illness after infection is 5.1 times higher in persons 65 years and older versus younger ages. Our results suggest that many unidentified mild influenza A(H7N9) infections may have occurred, with a lower bound of 210–550 infections to date.

Mice lacking the alpha4 nicotinic receptor subunit fail to modulate dopaminergic neuronal arbors and possess impaired dopamine transporter function

Neuronal nicotinic acetylcholine receptors (nAChRs) at presynaptic sites can modulate dopaminergic synaptic transmission by regulating dopamine (DA) release and uptake. Dopaminergic transmission in nigrostriatal and mesolimbic pathways is vital for the coordination of movement and is associated with learning and behavioral reinforcement. We reported recently that the D2 DA receptor plays a central role in regulating the arbor size of substantia nigra dopaminergic neurons. Given the known effects of nAChRs on dopaminergic neurotransmission, we assessed the ability of the alpha4 nAChR subunit to regulate arbor size of dopaminergic neurons by comparing responses of wild-type and alpha4 nAChR subunit knockout [alpha4(-/-)] mice to long-term exposure to cocaine, amphetamine, nicotine, and haloperidol, and after substantia nigra neurotoxic lesioning. We found that dopaminergic neurons in adult drug-naive alpha4(-/-) mice had significantly larger terminal arbors, and despite normal short-term behavioral responses to drugs acting on pre- and postsynaptic D2 DA receptors, they were unable to modulate their terminal arbor in response to pharmacological manipulation or after lesioning. In addition, although synaptosome DA uptake studies showed that the interaction of the D2 DA receptor and the dopamine transporter (DAT) was preserved in alpha4(-/-) mice, DAT function was found to be impaired. These findings suggest that the alpha4 subunit of the nAChR is an independent regulator of terminal arbor size of nigrostriatal dopaminergic neurons and that reduced functionality of presynaptic DAT may contribute to this effect by impairing DA uptake.

Granulomatous infectious diseases associated with tumor necrosis factor antagonists

The relationship between the use of tumor necrosis factor antagonists and onset of granulomatous infection was examined using data collected through the Adverse Event Reporting System of the US Food and Drug Administration for January 1998-September 2002. Granulomatous infections were reported at rates of approximately 239 per 100,000 patients who received infliximab and approximately 74 per 100,000 patients who received etanercept (P<.001). Tuberculosis was the most frequently reported disease, occurring in approximately 144 and approximately 35 per 100,000 infliximab-treated and etanercept-treated patients, respectively (P<.001). Candidiasis, coccidioidomycosis, histoplasmosis, listeriosis, nocardiosis, and infections due to nontuberculous mycobacteria were reported with significantly greater frequency among infliximab-treated patients. Seventy-two percent of these infection occurred < or =90 days after starting infliximab treatment, and 28% occurred after starting etanercept treatment (P<.001). These data indicate a risk of granulomatous infection that was 3.25-fold greater among patients who received infliximab than among those who received etanercept. The clustering of reports shortly after initiation of treatment with infliximab is consistent with reactivation of latent infection.

Recombinant paramyosin (rec-Sj-97) tested for immunogenicity and vaccine efficacy against Schistosoma japonicum in mice and water buffaloes

A primary vaccine candidate antigen against schistosomiasis is paramyosin (pmy), a myofibrillar protein found exclusively in invertebrates. Here we report the results of vaccine trials against the Asian schistosome undertaken on inbred and outbred mice and water buffaloes using a bacterially expressed and purified form of Schistosoma japonicum pmy (rec-Sj-97). Vaccination of the mice resulted in high levels of specific anti-pmy IgG antibodies when compared with adjuvant controls and significant reduction in worm burdens and in liver eggs. Furthermore, a significant reduction in liver eggs was recorded in two of the three water buffalo vaccine trials undertaken and, in all three trials, high levels of specific anti-pmy IgG antibodies were generated. There was no evidence of any toxic effects and the vaccine preparations and Quil A adjuvant were clearly well tolerated. The development of a vaccine intended for livestock animals such as bovines would be beneficial in two ways; directly by blocking transmission of schistosomiasis to humans and economically by contributing to healthier livestock. We are encouraged by the consistent efficacy in the mouse and the buffalo vaccine trials that resulted in a significant decrease in liver eggs. Indeed, predictions from mathematical models indicate that an egg reduction effect of 42-45% in buffaloes would be sufficient when combined with human treatment to control schistosomiasis japonica in the marshes and lakes along the middle and upper reaches of the Yangtze River, the most highly endemic areas for the disease in China.

Impact of polymer tether length on multiple ligand-receptor bond formation

The promoters of cell adhesion are ligands, which are often attached to flexible tethers that bind to surface receptors on adjacent cells. Using a combination of Monte Carlo simulations, diffusion reaction theory, and direct experiments (surface force measurements) of the biotin-streptavidin system, we have quantified polymer chain dynamics and the kinetics and spatial range of tethered ligand-receptor binding. The results show that the efficiency of strong binding does not depend solely on the molecular architecture or binding energy of the receptor-ligand pair, nor on the equilibrium configuration of the polymer tether, but rather on its "rare" extended conformations.

Effector genes altered in MCF-7 human breast cancer cells after exposure to fractionated ionizing radiation

Understanding the molecular mechanisms involved in the response of tumors to fractionated exposures to ionizing radiation is important for improving radiotherapy and/or radiochemotherapy. In the present study, we examined the expression of stress-related genes in an MCF-7 cell population (MCF-IR20) that has been derived through treatment with fractionated irradiation (2 Gy per fraction with a total dose of 40 Gy). MCF-IR20 cells showed a 1.6-fold increase in sensitization with dose at 10% isosurvival in a clonogenic assay, and a reduced growth delay ( approximately 15 h compared to approximately 27 h), compared to the parental MCF-7 cells treated with a single dose of 5 Gy. To determine which effector genes were altered in the MCF-IR20 cells, the expression of stress-related effector genes was measured using a filter with 588 genes (Clontech) that included major elements involved in cell cycle control, DNA repair, and apoptosis. Compared to MCF-7 cells that were not exposed to fractionated radiation, 19 genes were up- regulated (2.2-5.1-fold) and 4 were down-regulated (2.7-3.4- fold) in the MCF-IR20 cells. In agreement with the array results, 6 up-regulated genes tested by RT-PCR showed elevated expression. Also, activities of the stress-related transcription factors NFKB, TP53 and AP1 showed a 1.2-4.5-fold increase after a single dose of 5 Gy in MCF-IR20 cells compared with parental MCF-7 cells. However, when the radioresistant MCF-IR20 cell were cultured for more than 12 passages after fractionated irradiation (MCF-RV), radioresistance was lost, with the radiosensitivity being the same as the parental MCF- 7 cells. Interestingly, expression levels of CCNB1, CD9 and CDKN1A in MCF-RV cells returned to levels expressed by the parental cells, whereas the expression levels of three other genes, MSH2, MSH6 and RPA remained elevated. To determine if any of the changes in gene expression could be responsible for the induced radioresistance, CCNB1 and CDKN1A, both of which were up-regulated in MCF-IR20 cells and down-regulated in MCF-RV cells, were studied further by transfection with antisense oligonucleotides. Antisense of CCNB1 significantly reduced the clonogenic survival of MCF- IR20 cells at doses of 5 and 10 Gy, from 42% to 26% and from 5.7% to 1.0%, respectively. Antisense of CDKN1A, however, had no effect on radiation survival of MCF-IR20 cells. In summary, these results suggest that stress-related effector genes are altered in cells after treatment with fractionated irradiation, and that up-regulation of CCNB1 is responsible, at least in part, for radioresistance after fractionated irradiation.

Tumor targeting of radiometal labeled anti-CEA recombinant T84.66 diabody and t84.66 minibody: comparison to radioiodinated fragments

Recombinant antibody fragments offer potential advantages over intact monoclonal antibodies in the radioimmunoscintigraphy (RIS) of solid tumors. Due to their smaller molecular size, antibody fragments have shown rapid tumor targeting and blood clearance, a more uniform tumor distribution and a lower potential to elicit a human immune response. Previously, we have expressed two genetically engineered antibody fragments, the T84.66 diabody (scFv dimer) and the T84.66 minibody (scFv-CH3 dimer), specific to carcinoembryonic antigen (CEA). When radioiodinated, both antibody fragments exhibited rapid tumor targeting and rapid blood clearance in xenografted mice. To extend and optimize their future clinical RIS utility with radiometals, these antibody fragments were conjugated with the macrocycle 1,4,7,10-tetraazacyclododecane N,N',N' ',N' "-tetraacetic acid (DOTA) and labeled with 111In. Tumor targeting and biodistribution studies were carried out in athymic mice xenografted with a human colorectal tumor cell line, LS174T. The [111In]T84.66 diabody (55 kDa) exhibited very rapid tumor targeting with 12.5 +/- 0.4% injected dose per gram (% ID g(-1) +/- standard error) at 2 h and reached a maximum of 13.3 +/- 0.9% ID g(-1) at 6 h. However, kidney uptake was observed to reached a peak of 183.5 +/- 21.0% ID g(-1) at 6 h, a result similar to that reported by others for other low molecular weight fragments labeled with radiometals. Preadministration of an oral dose of D-lysine resulted in a 59% lowering of the renal accumulation at 6 h, but was accompanied by a 31% reduction of tumor uptake to 9.2 +/- 1.2% ID g(-1). The second recombinant antibody fragment, the [111In]T84.66 minibody (80 kDa), displayed rapid tumor targeting of 14.2 +/- 6.1% ID g(-1) at 2 h, and reached a maximum activity of 24.5 +/- 6.1% ID g(-1) by 12 h. Renal uptake achieved a plateau of 12-13% ID g(-1) which cleared to 7.2% ID g(-1) at 72 h. However, hepatic uptake was elevated and reached a maximum of 26.0 +/- 1.0% ID g(-1) at 12 h in these xenograft-bearing mice. Experiments in nontumor bearing mice showed a reduction of hepatic activity at 12 h to 16.6 +/- 1.5% ID g(-1), indicative of an intrinsic hepatic accumulation of the [111In]DOTA-T84.66 minibody or metabolites. While the anti-CEA [111In]DOTA-T84.66 diabody and T84.66 minibody retain the rapid tumor targeting properties of the radioiodinated form, the normal organ accumulation (kidneys and liver, respectively) of the [111In]DOTA forms appeared problematic for RIS and RIT applications. Development of alternative blocking strategies or new metabolizable chelates are under investigation to enhance the utility of the radiometal form of these and other promising recombinant antibody fragments.

Numerical selection of optimal tumor imaging agents with application to engineered antibodies

Three analytic indicators were used to compare five members of a monoclonal antibody (Mab) family. The cognates consisted of the genetically engineered intact chimeric IgGI (cT84.66) and related engineered fragments [scFv, diabody, minibody, F(ab')2] reactive against the same epitope of carcinoembryonic antigen (CEA). All analyses were based on radioiodinated Mabs targeting to colorectal xenografts of LS174T tumors in nude mice. Affinity constants were evaluated initially. A second indicator was the imaging figure of merit (IFOM) which determines how rapidly a statistically significant tumor image can be acquired. Finally, deconvolution was used to determine tumor temporal response to an arterial bolus. This last analysis gave the possible tumor accumulation in the absence of normal tissue sequestration. Affinities were all in excess of 10(8) M-1 and were highest for the divalent Mabs. Using the IFOM criterion, an 131I label was best suited as a radiolabel for the intact (IgG) T84.66, while an 123I label indicated optimal imaging with either minibody or F(ab')2. Deconvolution analyses showed that divalent members behaved similarly while the univalent member (scFv) had a tumor residence time smaller by an order of magnitude. The diabody had the largest impulse response function, but renal uptake may limit its present usefulness.

Genes regulated in human breast cancer cells overexpressing manganese-containing superoxide dismutase

The mitochondrial antioxidant enzyme manganese-containing superoxide dismutase (MnSOD) functions as a tumor suppressor gene. Reconstitution of MnSOD expression in several human cancer cell lines leads to reversion of malignancy and induces a resistant phenotype to the cytotoxic effects of TNF and hyperthermia. The signaling pathways that underlie these phenotypic changes in MnSOD-overexpressing cells are unknown, although alterations in the activity of several redox-sensitive transcription factors, including AP-1 and NF-kappaB, have been observed. To determine the downstream signaling molecules involved in MnSOD-induced cell resistant phenotype, in the present study we analyzed the expression profile of several groups of genes related to stress response, DNA repair, and apoptosis, in a human breast cancer MCF-7 cell line overexpressing MnSOD (MCF+SOD). Of 588 genes examined, 5 (0.85%) were up-regulated (2-42-fold), and 11 (1.9%) were down-regulated (2-33-fold) in the MCF+SOD cells compared to the parental MCF-7 cells. The five up-regulated genes were MET, GADD153, CD9, alpha-catenin and plakoglobin. The genes with the most significant down-regulation included: vascular endothelial growth factor receptor 1, TNF-alpha converting enzyme, and interleukin-1beta. GADD153 (involved in the repair of DNA double strand breaks) showed a 33-fold increase in microarray analysis and these results were confirmed by RT-PCR. To further determine the specificity in MnSOD-induced gene regulation, MCF+SOD cells were stably transfected with an antisense MnSOD sequence whose expression was controlled by a tetracycline-inducible regulator. Expression of three up-regulated genes was measured after induction of antisense MnSOD expression. Interestingly, expression level of GADD153 but not MET or CD9 was reduced 24 h after antisense MnSOD induction. Together, these results suggest that reconstitution of MnSOD in tumor cells can specifically modulate the expression of down-stream effector genes. GADD153 and other elements observed in the MCF+SOD cells may play a key role in signaling the MnSOD-induced cell phenotypic change.

Proteolysis of human hemoglobin by schistosome cathepsin D

Schistosomes feed on human blood. They employ proteases to degrade hemoglobin from ingested erythrocytes, using the residues released for amino acid metabolism. However, the identity and the role of the participating protease(s) are unclear and controversial. Confocal microscopy localized schistosomal cathepsin D to the parasite gastrodermis, and revealed elevated protease expression in females. At sub-cellular level, cathepsin D was localized to superficial digestive vacuoles of the gut and to cisternae of the gastrodermal rough endoplasmic reticulum. Schistosome cathepsin D, expressed in insect cells, autoactivated at pH 3.6 to a approximately 40 kDa form that cleaved the substrates o-aminobenzoyl-Ile-Glu-Phe-nitroPhe-Arg-leu-NH(2) and hemoglobin. The NH(2)-terminal residues of mature cathepsin D of Schistosoma japonicum and Schistosoma mansoni were Asn1 and Gly1, respectively, revealing that the proregion peptide was comprised of 35 residues. The proteases cleaved hemoglobin at pH 2.5--4.6, releasing numerous fragments. S. Japonicum cathepsin D cleaved at 13 sites, S. mansoni cathepsin D at 15 sites. Early cleavage sites were alpha Phe33-Leu34 and beta Phe41-Phe42, while others included alpha Leu109-Ala-110 and beta Leu14-Trp15, demonstrating a preference for bulky hydrophobic residues at P1 and P1'. Most of the schistosomal cathepsin D cleavage sites were discrete from those of human cathepsin D. The gastrodermal location, elevated expression in females, acidic pH optima, similar substrate preferences in two species, and the discrete substrate preferences compared with human cathepsin D together provide compelling support for the hypothesis that schistosomal cathepsin D plays an integral role in hemoglobin proteolysis, and might be selectively targeted by drugs based on protease inhibition.

Differential diagnosis of malignant lymphomas and related disorders by specific pattern of expression of immunophenotypic markers revealed by multiparameter flow cytometry (Review)

The introduction of monoclonal antibodies (mAbs) for cell immunophenotyping and use of flow cytometry with the progressively improving software for multivariate analyses have revolutionized the diagnosis and influenced the classification of hematologic neoplasms. In this review we focus on the practical application of flow cytometry in the diagnosis and classification of malignant lymphomas and related lymphoproliferative disorders with special emphasis on differential diagnosis. A general approach to the utilization of flow cytometry (FC) in hematopathology with an algorithm to diagnose the most common neoplasms is presented. We discuss precursor B-cell neoplasms, mature B-cell neoplasms (SLL/CLL, mantle cell lymphoma, marginal zone lymphoma, hairy cell leukemia, diffuse large B-cell lymphoma, plasma cell dyscrasias and lymphomas with plasmacytic differentiation), precursor T-lymphoblastic leukemia and mature (peripheral) T-cell neoplasms, including T-SLL/PLL, anaplastic cell lymphomas and large granular cell leukemia/lymphoma. The text is accompanied by characteristic FC scatterplots of the discussed entities.

Reduced BDNF mRNA expression in the Parkinson's disease substantia nigra

Brain-derived neurotrophic factor (BDNF) has potent effects on survival and morphology of dopaminergic neurons and thus its loss could contribute to death of these cells in Parkinson's disease (PD). In situ hybridization revealed that BDNF mRNA is strongly expressed by dopaminergic neurons in control substantia nigra pars compacta (SNpc). In clinically and neuropathologically typical PD, SNpc BDNF mRNA expression is reduced by 70% (P = 0.001). This reduction is due, in part, to loss of dopaminergic neurons which express BDNF. However, surviving dopaminergic neurons in the PD SNpc also expressed less BDNF mRNA (20%, P = 0.02) than their normal counterparts. Moreover, while 15% of control neurons had BDNF mRNA expression >1 SD below the control mean, twice as many (28%) of the surviving PD SNpc dopaminergic neurons had BDNF mRNA expression below this value. This 13% difference in proportions (95% CI 8-17%, P < or = 0.000001) indicates the presence of a subset of neurons in PD with particularly low BDNF mRNA expression. Moreover, both control and PD neurons displayed a direct relationship between the density of BDNF mRNA expression per square micrometer of cell surface and neuronal size (r(2) = 0.93, P </= 0.00001) which was lost only in PD neurons expressing the lowest levels of BDNF mRNA. If BDNF is an autocrine/paracrine factor for SNpc dopaminergic neurons, loss of BDNF-expressing neurons may compromise the well-being of their surviving neighbors. Moreover, neurons expressing particularly low levels of BDNF mRNA may be those at greatest risk of injury in PD and possibly the trigger for the degeneration itself.

Phenotypic characterization of an alpha 4 neuronal nicotinic acetylcholine receptor subunit knock-out mouse

Neuronal nicotinic acetylcholine receptors (nAChR) are present in high abundance in the nervous system (Decker et al., 1995). There are a large number of subunits expressed in the brain that combine to form multimeric functional receptors. We have generated an alpha(4) nAChR subunit knock-out line and focus on defining the behavioral role of this receptor subunit. Homozygous mutant mice (Mt) are normal in size, fertility, and home-cage behavior. Spontaneous unconditioned motor behavior revealed an ethogram characterized by significant increases in several topographies of exploratory behavior in Mt relative to wild-type mice (Wt) over the course of habituation to a novel environment. Furthermore, the behavior of Mt in the elevated plus-maze assay was consistent with increased basal levels of anxiety. In response to nicotine, Wt exhibited early reductions in a number of behavioral topographies, under both unhabituated and habituated conditions; conversely, heightened levels of behavioral topographies in Mt were reduced by nicotine in the late phase of the unhabituated condition. Ligand autoradiography confirmed the lack of high-affinity binding to radiolabeled nicotine, cytisine, and epibatidine in the thalamus, cortex, and caudate putamen, although binding to a number of discrete nuclei remained. The study confirms the pivotal role played by the alpha(4) nAChR subunit in the modulation of a number of constituents of the normal mouse ethogram and in anxiety as assessed using the plus-maze. Furthermore, the response of Mt to nicotine administration suggests that persistent nicotine binding sites in the habenulo-interpeduncular system are sufficient to modulate motor activity in actively exploring mice.

Pharmacogenetics: role in modifying drug dosage regimens

With the advent of new molecular biology and scientific techniques, there is better understanding of genetic polymorphisms in oxidative drug metabolism systems today. These systems are important in pharmacogenetic studies which genotype polymorphic alleles encoding drug metabolising enzymes to enable the individual's drug metabolising phenotype to be found. Once found, the knowledge can be used to tailor drug dosage regimens to an individual to maximise therapeutic efficacy and minimise adverse drug reactions (ADRs). The knowledge could also be used to optimise drug development programmes so that all the subgroups within a target population are adequately represented in clinical trails.

X-ray and neutron surface scattering for studying lipid/polymer assemblies at the air-liquid and solid-liquid interfaces

Simple mono- and bilayers, built of amphiphilic molecules and prepared at air-liquid or solid-liquid interfaces, can be used as models to study such effects as water penetration, hydrocarbon chain packing, and structural changes due to head group modification. In the paper, we will discuss neutron and X-ray reflectometry and grazing incidence X-ray diffraction techniques used to explore structures of such ultra-thin organic films in different environments. We will illustrate the use of these methods to characterize the morphologies of the following systems: (i) polyethylene glycol-modified distearoylphosphatidylethanolamine monolayers at air-liquid and solid-liquid interfaces; and (ii) assemblies of branched polyethyleneimine polymer and dimyristoylphophatidylcholine lipid at solid-liquid interfaces.

High-resolution microPET imaging of carcinoembryonic antigen-positive xenografts by using a copper-64-labeled engineered antibody fragment

Rapid imaging by antitumor antibodies has been limited by the prolonged targeting kinetics and clearance of labeled whole antibodies. Genetically engineered fragments with rapid access and high retention in tumor tissue combined with rapid blood clearance are suitable for labeling with short-lived radionuclides, including positron-emitting isotopes for positron-emission tomography (PET). An engineered fragment was developed from the high-affinity anticarcinoembryonic antigen (CEA) monoclonal antibody T84.66. This single-chain variable fragment (Fv)-C(H)3, or minibody, was produced as a bivalent 80 kDa dimer. The macrocyclic chelating agent 1,4,7, 10-tetraazacyclododecane-N,N',N", N"'-tetraacetic acid (DOTA) was conjugated to the anti-CEA minibody for labeling with copper-64, a positron-emitting radionuclide (t(1/2) = 12.7 h). In vivo distribution was evaluated in athymic mice bearing paired LS174T human colon carcinoma (CEA positive) and C6 rat glioma (CEA negative) xenografts. Five hours after injection with (64)Cu-DOTA-minibody, microPET imaging showed high uptake in CEA-positive tumor (17.9% injected dose per gram +/- 3.79) compared with control tumor (6.0% injected dose per gram +/- 1.0). In addition, significant uptake was seen in liver, with low uptake in other tissues. Average target/background ratios relative to neighboring tissue were 3-4:1. Engineered antibody fragments labeled with positron-emitting isotopes such as copper-64 provide a new class of agents for PET imaging of tumors.

Truncation of blood curves to enhance imaging and therapy with monoclonal antibodies

Targeting of monoclonal antibody (Mab) to solid tumor sites is a function of the blood curve of activity versus time. It has been suggested that the blood curve be artificially reduced to approach zero so that the contrast between tumor and blood uptake is maximized. We analyzed tumor uptake as a function of the time tc of blood curve truncation. By using a convolution approach, we were able to find the optimal times for setting the blood curve to zero in either diagnostic or therapeutic animal examples. Two iodinated cT84.66 anti-CEA engineered fragments, diabody and minibody, were considered using previous data from nude mouse studies involving the LS174T colorectal tumor model. Figures of merit (FOMs) were used to compare ordinary and truncated blood curves and their associated tumor accumulations. Using a 1231 label, it was seen that the appropriate time for diagnostic truncation occurred when tumor uptake, as measured, was a maximum. The corresponding point for therapy (with 1311 as a label) was at infinite time. We also demonstrated that the use of traditional indices led to ambiguities in the choice of truncation times. The traditional therapy index, the ratio of the integral of the tumor uptake to the integral of the blood uptake, was found to be a numerical constant independent of tc. This ratio was proved to be the integral of the tumor impulse response function. Use of such convolution techniques to assess truncation of the perfused material is probably also applicable to multistep processes as well as to lesion targeting with other tumor-specific pharmaceuticals.

Pharmacogenetics: the molecular genetics of CYP2D6 dependent drug metabolism

INTRODUCTION

Genetic variation of drug metabolising enzymes has been recognised as one of the major causes of the inter-individual variability to drug response. The vast majority of drugs are degraded via a small number of metabolic pathways, mainly by microsomal P-450 enzymes localised in the liver and, to a minor extent, in the small intestine. Of these, CYP3A4 is the isozyme involved in the metabolism of most of the clinically useful drugs (50%). This is followed by CYP2D6 (20%), CYP2C9 and CYP2C19 (15%). In addition, minor pathways are catalysed by CYP2E1, CYP1A2, CYP2A6 and unidentified P-450s. Almost 40% of human P-450 dependent drug metabolism is carried out by genetically polymorphic enzymes. Polymorphisms generated by mutations in the genes for these enzymes cause quantitatively or qualitatively altered enzyme expression or activity through multiple molecular mechanisms. While CYP3A4 genetic polymorphisms are just beginning to be unraveled, extensive studies on the CYP2D6 gene over the last decade have identified at least 53 alleles. Of these, more than 20 of them are known to significantly alter the metabolism of CYP2D6 substrates.

METHODS

This article reviews the information derived from various studies over the past decade and explains the molecular basis of functional differences in CYP2D6 variants, especially with respect to inter-ethnic differences and their clinical implications.

RESULTS

CYP2D6 activity ranges from complete absence to ultra-rapid metabolism. Large inter-individual and inter-ethnic variability exists in the activity of the enzyme, and consequently in the disposition of drugs undergoing oxidative metabolism.

CONCLUSIONS

Pharmacokinetic differences resulting from these polymorphisms show potentially important clinical consequences.