Leveraging Programmatic Collaboration for a Radiopharmaceutical Clinic

Radiation oncologists, radiopharmacists, nuclear medicine physicians, and medical oncologists have seen a renewed clinical interest in radiopharmaceuticals for the curative or the palliative treatment of cancer. To allow for the discovery and the clinical advancement of targeted radiopharmaceuticals, these stakeholders have reformed their trial efforts and remodeled their facilities to accommodate the obligations of a program centered upon radioactive investigational drug products. Now considered informally as drugs and not beam radiotherapy, radiopharmaceuticals can be more easily studied in the traditional clinical trial enterprise ranging from phase 0-I to phase III studies. Resources and physical facilities allocated to radiopharmaceuticals have brought forth new logistics and patient experience for safe and satisfactory drug delivery. The clinical use of theranostic agents-that is, diagnostic and therapeutic radionuclide pairs-has accelerated radiopharmaceutical development.

Cesium-131 Low-Dose Rate Interstitial Brachytherapy as a Salvage Re-Irradiation Technique in Treating Cervical and Uterine Cancer Pelvic Recurrence with Prior History of Pelvic Radiation

PURPOSE/OBJECTIVE(S)

Pelvic recurrence among cervical and uterine cancer patients with prior history of pelvic radiation is a poor prognostic factor and remains challenging. The standard of care is pelvic exenteration, which is a highly morbid surgical procedure. The purpose of this study is to report local control rate and toxicity profile of Cesium-131 low-dose rate interstitial brachytherapy (LDR) as a salvage re-irradiation technique in managing pelvic relapse.

MATERIALS/METHODS

We reviewed procedures and outcomes from patients with previously irradiated uterine corpus or cervix neoplasms, who subsequently relapsed and then underwent cesium-131 LDR implants between January 2016 and December 2022. Patient demographics, treatment planning variables, and disease response were reviewed. Acute toxicities, late toxicities, and local control rate were compiled for this study.

RESULTS

A total of 12 eligible patients (6 cervical and 6 uterine cancer) with 16 cesium-131 LDR implants were included in this study. The majority (75%) of pelvic relapses occurred at the exocervix (cervix-intact) or vaginal cuff (post-hysterectomy). Median time from disease relapse to cesium implant was 32 days. The average area of implementation was 9 cm2 and average number of seeds implanted was 16. The mean prescription dose was 50 Gy. Six patients also received high-dose rate vaginal intracavitary brachytherapy in addition to cesium-131 LDR. Median follow up was 12 months. 81% of cesium implants achieved complete response at first post-treatment follow-up, while the remaining 19% demonstrated partial response. The 6-months local control rate was 79%. After cesium implant, 25% patients had local recurrence and 33% with distal metastasis. The most reported acute toxicities included vaginal mucositis (63%), dysuria (50%) and pain (19%). All patients had various degrees of vaginal stenosis and strictures long-term. Only 1 (8%) out of 12 patients, with 4 repeated cesium-131 LDR implants, developed a rectovaginal fistula and chronic pain.

CONCLUSION

Cesium-131 LDR interstitial brachytherapy is a safe and feasible salvage re-irradiation technique in treating pelvic relapse among uterine corpus or cervix cancer patients with prior history of pelvic radiation. Local control rate at 6-months was acceptable with minimum toxicity. Long-term follow up is warranted to validate the efficacy of cesium-131 LDR. We conclude that cesium-131 LDR interstitial brachytherapy is a promising alternative to pelvic exenteration in selective patient population. Future prospective study is warranted.

Leveraging Radiopharmaceutical Programmatic Collaboration for Management of Pretherapy and On-treatment Urinary Incontinence

ABSTRACT

Many parenteral radiopharmaceuticals available as anticancer therapy are filtered by the kidneys and excreted in the urine. Here, physician leaders of radiation medicine, nuclear medicine/molecular imaging, and the radiotheranostics programs as well as radiation safety officers, collaborated to develop a decision-making guideline for the administration of therapeutic radiopharmaceuticals in patients with pretherapy or day-of-treatment incontinence. We discussed challenges and opportunities in the screening of patients in urine collection strategies according to grade of urinary incontinence and in subsequent coordination of care. Lutetium-177 ( 177 Lu)-based radiopharmaceutical therapies provided clinical examples of how our procedures were operationalized. Our key management issues of urinary incontinence were cutaneous radiation injury and redness, infection, or pain. In response, we developed clinical practice guidelines for the recognition and management of incontinence-related adverse events. Common adverse events of urinary incontinence were noted in this study. Our how-to guideline for the safe administration of therapeutic radiopharmaceuticals for patients with urinary incontinence warrants further investigation and should continue to be evaluated across all radiopharmaceutical therapy agents.

A phase I study of the Wee1 kinase inhibitor adavosertib (AZD1775) in combination with chemoradiation in cervical, upper vaginal, and uterine cancers

OBJECTIVE

Wee1 kinase is a crucial regulator of the G2/M checkpoint which prevents entry of damaged DNA into mitosis. Adavosertib (AZD1775), a selective inhibitor of Wee1, induces G2 escape and increases cytotoxicity when combined with DNA damaging agents. We aimed to evaluate the safety and efficacy of adavosertib in combination with definitive pelvic radiotherapy and concurrent cisplatin in patients with gynecological cancers.

METHODS

A multi-institutional, open-label phase I trial was designed to assess dose escalation (3+3 design) of adavosertib in combination with standard chemoradiation. Eligible patients with locally advanced cervical, endometrial or vaginal tumors were treated with a 5-week course of pelvic external beam radiation 45-50 Gy in 1.8-2 Gy daily fractions plus concurrent weekly cisplatin 40 mg/m2 and adavosertib 100 mg/m2 on days 1, 3 and 5 of each week during chemoradiation. The primary endpoint was to determine the recommended phase II dose of adavosertib. Secondary endpoints included toxicity profile and preliminary efficacy.

RESULTS

Ten patients were enrolled (nine locally advanced cervical and one endometrial cancer). Two patients experienced a dose-limiting toxicity at dose level 1 (adavosertib 100 mg by mouth daily on days 1, 3 and 5), including one patient with grade 4 thrombocytopenia, and one with treatment hold >1 week due to grade 1 creatinine elevation and grade 1 thrombocytopenia. At dose level -1 (adavosertib 100 mg by mouth daily on days 3 and 5), one out of five patients enrolled had a dose-limiting toxicity in the form of persistent grade 3 diarrhea. The overall response rate at 4 months was 71.4%, including four complete responses. At 2 years follow-up, 86% of patients were alive and progression-free.

CONCLUSION

The recommended phase II dose could not be determined due to clinical toxicity and early trial closure. Preliminary efficacy appears promising, yet selecting the adequate dose/schedule in combination chemoradiation warrants further investigation to limit overlapping toxicities.

Hemoglobin level associates with survival in women from Appalachian Kentucky with uterine cervix cancer

Introduction

The purpose of this retrospective study was to determine the relationship between pretherapy hemoglobin levels and progression-free survival among women with uterine cervix cancer undergoing concurrent weekly cisplatin and radiotherapy followed by brachytherapy.

Methods

Patients with advanced-stage II-IVA uterine cervix cancer were grouped by hemoglobin level (Hgb ≥ 12.0, 11.9-10.0, or < 10.0 g/dL). Endpoints were progression-free survival, overall survival, and local control.

Results

Between 01/2001 and 07/2022, 168 patients contributed demographic, tumor, pretherapy hemoglobin, and outcome data with a median follow-up of 31 months. Progression-free survival at three years was 73% (95% confidence interval: 58%-84%), 71% (95% confidence interval: 56%-82%), and 62% (95% confidence interval: 44%-75%) for the Hgb ≥ 12.0, 11.9-10.0, or < 10.0 g/dL groups, respectfully (P < 0.001). In addition, pretherapy hemoglobin levels were significant with treatment outcome when included in a multivariate analysis of prognostic variables.

Discussion

In conclusion, the difference in pretherapy hemoglobin level was prognostic of progression-free survival.

A case report of typhlitis during novel use of ropidoxuridine-capecitabine-radiotherapy for treatment-naïve rectal cancer

BACKGROUND

Rectal carcinomas are tumors that arise from the last 12 cm of the large intestine closest to the anus. They generally have a modest prognosis exacerbated by a high local recurrence rate if radiosensitizing chemotherapy is not given during radiotherapy. This case report discusses the clinical trial treatment of a patient with rectal adenocarcinoma by a new ropidoxuridine-capecitabine-radiotherapy combination. This case report is novel due to the patient's participation in an accelerated titration phase I clinical trial and the resultant rare adverse event of treatment-related sigmoid typhlitis.

CASE PRESENTATION

The patient was an 82-year-old female who noticed hematochezia and change in stool caliber over a period of 3 months. A rectal mass was identified by biopsy as a microsatellite stable adenocarcinoma. A planned total neoadjuvant treatment involved eight cycles of leucovorin calcium (folinic acid)-fluorouracil-oxaliplatin (mFOLFOX6) chemotherapy, followed by a clinical trial combination of ropidoxuridine-capecitabine-radiotherapy, prior to definitive surgery. The patient began daily intensity modulated pelvic radiotherapy with concurrent twice-daily oral ropidoxuridine and twice-daily oral capecitabine to be given over 6 weeks. After 14 days of ropidoxuridine-capecitabine-radiotherapy, the patient developed sigmoid typhlitis requiring a 10-day hospitalization and 14-day disruption of treatment. The patient died 27 days after the start of ropidoxuridine-capecitabine-radiotherapy. This adverse event was listed as a definite attribution to the ropidoxuridine-capecitabine treatment; pharmacokinetic and pharmacodynamic data showed low ropidoxuridine metabolite DNA incorporation and high capecitabine metabolite concentration. The accelerated titration phase I clinical trial has been subsequently closed to accrual (NCT04406857).

CONCLUSIONS

We believe this case report demonstrates the decision-making process for terminating a phase I accelerated titration designed clinical trial. The report also presents the rare complication of sigmoid typhlitis as a treatment-attributed adverse event. In this case, a ropidoxuridine-capecitabine combination was used as an investigational radiosensitizing treatment now with a narrower future clinical development pathway.

Human gastrin- releasing peptide receptor expression in women with uterine cervix cancer

Introduction

²¹²Pb-DOTAM-GRPR1 is a pharmaceutical radioimmunoconjugate consisiting of an α-particle-emitting radionuclide lead-212 (²¹²Pb), a metal chelator DOTAM (1,4,7,10-tetrakis(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane), and a gastrin-releasing peptide receptor (GRPR)-targeted antagonist currently being evaluated as therapy in uterine cervix and other cancer types. Previous studies have revealed that a variable proportion of uterine cervix cancer tumors overexpress the radiopharmaceutical target GRPR when assessed by cell proportion and staining intensity immunoreactive scores (IRS). Tumor response to ²¹²Pb-DOTAM-GRPR1 strongly associates with GRPR overexpression, and therefore, it seems reasonable to assess uterine cervix cancer GRPR immunoreactivity for greater insight into the feasibility of using ²¹²Pb-DOTAM-GRPR1 as a radiopharmaceutical treatment.

Methods

We examined a series of 33 uterine cervix cancer paraffin-embedded tumors in order to establish whether this tumor type overexpresses GRPR at an IRS score of 6 or higher, as ²¹²Pb-DOTAM-GRPR1 is currently being evaluated in clinical trials against tumors showing such a level of expression.

Results

The results show that five of five (100%) primary adenocarcinomas and 10 of 16 (63%) primary squamous cell tumors overexpress GRPR at an IRS score of 6 or higher.

Discussion

The frequency of overexpression in this study suggests that ²¹²Pb-DOTAM-GRPR1 radiopharmaceutical treatment may be useful in the management of persistent, recurrent, or metastatic uterine cervix cancer patients. A phase I clinical trial involving patients with metastatic uterine cervix cancer is currently underway (NCT05283330).

Human epidermal growth factor receptor 2 expression in women with uterine cervix adenocarcinoma from Appalachian Kentucky

Introduction

High-risk human epidermal growth factor receptor 2 (HER2)-positive adenocarcinomas associate with early recurrence and death, prompting consideration of novel radiotherapeutic options like a trastuzumab-linked thorium-227 alpha-particle emitting radionuclide.

Methods

We conducted a retrospective pilot biomarker study of uterine cervix cancers among patients in Appalachian Kentucky, to characterize an exploitable triage biomarker like HER2 expression before starting a prospective phase 0 trial.

Results

Most (60%) adenocarcinomas showed HER2 cell-surface overexpression, whereas squamous cell carcinomas (4%) did not do so.

Discussion

Further validation tests of HER2 expression as a triage biomarker for radiopharmaceutical selection are warranted.

Current gaps and opportunities in screening, prevention, and treatment of cervical cancer

In their fiscal year 2021 reports, the US House and Senate Appropriations Committees requested that the National Institutes of Health (NIH) evaluate current research related to women's health and topics that include stagnant cervical cancer survival. In response, the NIH Office of Research on Women's Health, with input from women's health experts; members of the public; representatives from NIH institutes, centers, and offices; and members of the NIH Advisory Committee on Research on Women's Health, reviewed the public health needs and current NIH activities on cervical cancer. The Advancing NIH Research on the Health of Women: A 2021 Conference held in October 2021 reviewed these findings and allowed the identification of opportunities to strengthen research. In this review, the authors summarize public health needs related to cervical cancer and NIH activities in this realm. Cervical cancer has become a rare disease in the United States, yet significant portions of the US population remain under screened or unscreened for cervical cancer, human papillomavirus vaccination rates remain low, access to high-quality treatment remains a challenge for many, and large inequities by race and ethnicity persist. Novel, inclusive, and intentional research is needed to produce improvements in cervical cancer survival within the United States.

A single arm phase II study of bone-targeted Sn-117 m-DTPA in symptomatic castration-resistant prostate cancer with skeletal metastases

BACKGROUND

Several bone-seeking radionuclides have been developed for palliation of metastatic bone pain since 1956, however, so far radium-223 dichloride is the first and only Food and Drug Administration (FDA) approved targeted alpha therapy for metastatic castration-resistant prostate cancer (mCRPC) based on ALSYMPCA phase 3 study. While radium-223 does improve pain and overall survival outcomes, the improvement can come at the expense of side effects such as bone marrow toxicity. The development of new and better treatment with long-standing pain relief is clearly an unmet medical need.

METHODS

The study is a non-randomized phase II study. The study population consists of 25 patients with CRPC who had progressed on any lines of prior therapies and whose serum testosterone level is less than 50 ng/dl and have metastatic lesions to at least two bone sites, with at least one site that has clinically meaningful pain at baseline (≥ 4 on an 11-point intensity scale). Eligible patients will be given two cycles of Sn-117 m-DTPA every 8 weeks or 56 days. Treatment will be administered by slow IV injection over 5-10 min. Retreatment after two cycles is allowed if patients meet the following retreatment criteria. The primary objective is to evaluate the efficacy of Sn-117 m-DTPA on sustained pain response in patients with CRPC metastatic to at least two bone sites and at least one with clinically meaningful pain at baseline (≥ 4 on an 11-point pain intensity scale). Sustained pain response is defined as: 1) achieving pain index ≤ 3 within a 12-week period and 2) maintaining pain index ≤ 3 over a 16-week period. The secondary objectives are: safety and tolerability, measurement of Sn-117 m-DTPA activity by gamma-camera dosimetry scans, therapeutic efficacy, time to the first symptomatic skeletal event, duration of pain response, changes in PSA and ALP levels, patient-reported outcomes and progression free survival and overall survival.

DISCUSSION

Sn-117 m-DTPA is a unique bone-targeting theranostic radiopharmaceutical agent that selectively binds most heavily to bone metastases sites. This study will be the first prospective phase II trial to assess the pain efficacy and anti-tumor activity of Sn-117 m-DTPA in mCRPC with at least one clinically meaningful pain at baseline.

TRIAL REGISTRATION

ClincialTrials.gov Identifier: NCT04616547.

Adding Base-Excision Repair Inhibitor TRC102 to Standard Pemetrexed-Platinum-Radiation in Patients with Advanced Nonsquamous Non-Small Cell Lung Cancer: Results of a Phase I Trial

PURPOSE

TRC102, a small-molecule base-excision repair inhibitor, potentiates the cytotoxicity of pemetrexed and reverses resistance by binding to chemotherapy-induced abasic sites in DNA. We conducted a phase I clinical trial combining pemetrexed and TRC102 with cisplatin-radiation in stage III nonsquamous non-small cell lung cancer (NS-NSCLC).

PATIENTS AND METHODS

Fifteen patients were enrolled from 2015 to 2019. The primary objective was to determine the dose-limiting toxicity and maximum tolerated dose of TRC102 in combination with pemetrexed, cisplatin, and radiotherapy. Secondary objectives were to assess toxicity, tumor response, and progression-free survival at 6 months. Based on our preclinical experiments, pemetrexed-TRC102 was given on day 1, and cisplatin/radiotherapy was initiated on day 3. This schedule was duplicated in the second cycle. After completion, two additional cycles of pemetrexed-cisplatin were given. Toxicities were assessed using NCI CTACAE versions 4/5.

RESULTS

The median age was 69 years (45-79) with the median follow-up of 25.7 months (range, 7.9-47.4). No dose-limiting toxicities and no grade 5 toxicity were seen. Hematologic and gastrointestinal toxicities were the most common side effects. No clinical radiation pneumonitis was seen. Of 15 evaluable patients, three had complete response (20%), and 12 had partial response (80%). The 6-month progression-free survival was 80%, and the 2-year overall survival was 83%.

CONCLUSIONS

Pemetrexed-TRC102 combined with cisplatin/radiotherapy in NS-NSCLC is safe and well tolerated. The recommended phase II dose is 200 mg TRC102 along with cisplatin-pemetrexed. No additional safety signal was seen beyond the expected CRT risks. A phase II trial, integrating post-CRT immunotherapy with this aggressive DNA-damaging regimen, is warranted.

Characterization of Uterine Cervix Cancers in Women from Appalachian Kentucky

Uterine cervix cancer (UCCx) is clinically and socioeconomically diverse among women in the United States (US), which obscures the discovery of effective radiochemotherapy approaches for this disease. UCCx afflicts 7.5 per 100,000 American women nationally but 11.7 per 100,000 women in Appalachian Kentucky (AppKY), when age-adjusted to the 2000 US standard population. Epidemiological chart review was performed on 212 women with UCCx treated at the University of Kentucky (UKY) between January 2001 and July 2021. Demographics, tumor characteristics, and relative radiochemotherapy dose and schedule intensity were compared among AppKY and non-AppKY cohorts as well as Surveillance, Epidemiology, and End Results (SEER) data. One hundred thirty-eight (65%) of 212 women seeking radiochemotherapy treatment for UCCx resided in AppKY. Most (80%) sought external-beam radiochemotherapy close to their AppKY residence. Brachytherapy was then most frequently (96%) conducted at UKY. Cancer stage at diagnosis was significantly more advanced in AppKY residents. Women residing in AppKY had a median 10-week radiochemotherapy course, longer than an 8-week guideline. Estimated survival in women residing in AppKY was 8% lower than US national averages. In summary, this study identified an increased percentage of advanced-stage UCCx cancer at diagnosis arising in AppKY residents, with a confounding population-specific delay in radiochemotherapy schedule intensity lowering survival.

Abstract IACC0601: Radiopharmaceuticals and their future in cancer care

Radiopharmaceutical agents have been an appealing treatment approach since the use of 131I to treat thyroid malignancies. Advances in cancer radiobiology and radiochemistry have brought radiopharmaceuticals forward to the cutting edge of oncology clinical research. The National Cancer Institute (NCI) and its partnering academic and clinical research networks monitor radiopharmaceutical discoveries that might be incorporated into cancer treatment strategies for patients with unmet therapeutic needs. Such endeavors happen through leveraged partnerships between NCI's Cancer Therapy Evaluation Program (CTEP), its Radiation Research Program (RRP), and academic institutions in the Experimental Therapeutics Clinical Trials Network (ETCTN). If innovative discoveries are made, NCI supports clinician scientists to plan new and original radiopharmaceutical phase I and II monotherapy or combination trials. The clinical trial infrastructure needs, such as radiopharmaceutical dosimetry and treatment planning, are now available in government workflow and regulatory oversight. This presentation introduces a modern approach to the clinical development of radiopharmaceutical agents in an era of molecular targets and personalized cancer therapeutics.

Citation Format: Charles A. Kunos. Radiopharmaceuticals and their future in cancer care [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr IACC0601.

Radiopharmaceutical Validation for Clinical Use

Radiopharmaceuticals are reemerging as attractive anticancer agents, but there are no universally adopted guidelines or standardized procedures for evaluating agent validity before early-phase trial implementation. To validate a radiopharmaceutical, it is desirous for the radiopharmaceutical to be specific, selective, and deliverable against tumors of a given, molecularly defined cancer for which it is intended to treat. In this article, we discuss four levels of evidence—target antigen immunohistochemistry, in vitro and in vivo preclinical experiments, animal biodistribution and dosimetry studies, and first-in-human microdose biodistribution studies—that might be used to justify oncology therapeutic radiopharmaceuticals in a drug-development sequence involving early-phase trials. We discuss common practices for validating radiopharmaceuticals for clinical use, everyday pitfalls, and commonplace operationalizing steps for radiopharmaceutical early-phase trials. We anticipate in the near-term that radiopharmaceutical trials will become a larger proportion of the National Cancer Institute Cancer Therapy Evaluation Program (CTEP) portfolio.

Adavosertib plus gemcitabine for platinum-resistant or platinum-refractory recurrent ovarian cancer: a double-blind, randomised, placebo-controlled, phase 2 trial

BACKGROUND

The Wee1 (WEE1hu) inhibitor adavosertib and gemcitabine have shown preclinical synergy and promising activity in early phase clinical trials. We aimed to determine the efficacy of this combination in patients with ovarian cancer.

METHODS

In this double-blind, randomised, placebo-controlled, phase 2 trial, women with measurable recurrent platinum-resistant or platinum-refractory high-grade serous ovarian cancer were recruited from 11 academic centres in the USA and Canada. Women were eligible if they were aged 18 years or older, had an Eastern Cooperative Oncology Group performance status of 0-2, a life expectancy of more than 3 months, and normal organ and marrow function. Women with ovarian cancer of non-high-grade serous histology were eligible for enrolment in a non-randomised exploratory cohort. Eligible participants with high-grade serous ovarian cancer were randomly assigned (2:1), using block randomisation (block size of three and six) and no stratification, to receive intravenous gemcitabine (1000 mg/m2 on days 1, 8, and 15) with either oral adavosertib (175 mg) or identical placebo once daily on days 1, 2, 8, 9, 15, and 16, in 28-day cycles until disease progression or unacceptable toxicity. Patients and the team caring for each patient were masked to treatment assignment. The primary endpoint was progression-free survival. The safety and efficacy analysis population comprised all patients who received at least one dose of treatment. The trial is registered with ClinicalTrials.gov, NCT02151292, and is closed to accrual.

FINDINGS

Between Sept 22, 2014, and May 30, 2018, 124 women were enrolled, of whom 99 had high-grade serous ovarian cancer and were randomly assigned to adavosertib plus gemcitabine (65 [66%]) or placebo plus gemcitabine (34 [34%]). 25 women with non-high-grade serous ovarian cancer were enrolled in the exploratory cohort. After randomisation, five patients with high-grade serous ovarian cancer were found to be ineligible (four in the experimental group and one in the control group) and did not receive treatment. Median age for all treated patients (n=119) was 62 years (IQR 54-67). Progression-free survival was longer with adavosertib plus gemcitabine (median 4·6 months [95% CI 3·6-6·4] with adavosertib plus gemcitabine vs 3·0 months [1·8-3·8] with placebo plus gemcitabine; hazard ratio 0·55 [95% CI 0·35-0·90]; log-rank p=0·015). The most frequent grade 3 or worse adverse events were haematological (neutropenia in 38 [62%] of 61 participants in the adavosertib plus gemcitabine group vs ten [30%] of 33 in the placebo plus gemcitabine group; thrombocytopenia in 19 [31%] of 61 in the adavosertib plus gemcitabine group vs two [6%] of 33 in the placebo plus gemcitabine group). There were no treatment-related deaths; two patients (one in each group in the high-grade serous ovarian cancer cohort) died while on study medication (from sepsis in the experimental group and from disease progression in the control group).

INTERPRETATION

The observed clinical efficacy of a Wee1 inhibitor combined with gemcitabine supports ongoing assessment of DNA damage response drugs in high-grade serous ovarian cancer, a TP53-mutated tumour type with high replication stress. This therapeutic approach might be applicable to other tumour types with high replication stress; larger confirmatory studies are required.

FUNDING

US National Cancer Institute Cancer Therapy Evaluation Program, Ontario Institute for Cancer Research, US Department of Defense, Princess Margaret Cancer Foundation, and AstraZeneca.

A New Generation of "Magic Bullets" for Molecular Targeting of Cancer

A two-step molecular targeting approach involving a self-assembling and disassembling (SADA) bispecific antibody platform and DOTA-radioconjugates allows tumor-specific delivery of diagnostic and therapeutic payloads. Low immunogenicity and the modular nature of SADA allow its optimization to safely and repeatedly deliver a variety of payloads to tumors expressing diverse tumor-specific antigens.See related article by Santich et al., p. 532.

Radiopharmaceutical Chemistry and Drug Development-What's Changed?

Radiation oncologists and nuclear medicine physicians have seen a resurgence in the clinical use of radiopharmaceuticals for the curative or palliative treatment of cancer. To enable the discovery and the development of new targeted radiopharmaceutical treatments, the United States National Cancer Institute has adapted its clinical trial enterprise to accommodate the requirements of a development program with investigational agents that have a radioactive isotope as part of the studied drug product. One change in perspective has been the consideration of investigational radiopharmaceuticals as drugs, with maximum tolerable doses determined by normal organ toxicity frequency like in drug clinical trials. Other changes include new clinical trial enterprise elements for biospecimen handling, adverse event reporting, regulatory conduct, writing services, drug master files, and reporting of patient outcomes. Arising from this enterprise, the study and clinical use of alpha-particle and beta-particle emitters have emerged as an important approach to cancer treatment. Resources allocated to this enterprise have brought forward biomarkers of molecular pathophysiology now used to select treatment or to evaluate clinical performance of radiopharmaceuticals. The clinical use of diagnostic and therapeutic radionuclide pairs is anticipated to accelerate radiopharmaceutical clinical development.

NRG Oncology/RTOG Consensus Guidelines for Delineation of Clinical Target Volume for Intensity Modulated Pelvic Radiation Therapy in Postoperative Treatment of Endometrial and Cervical Cancer: An Update

PURPOSE

Accurate target definition is critical for the appropriate application of radiation therapy. In 2008, the Radiation Therapy Oncology Group (RTOG) published an international collaborative atlas to define the clinical target volume (CTV) for intensity modulated pelvic radiation therapy in the postoperative treatment of endometrial and cervical cancer. The current project is an updated consensus of CTV definitions, with removal of all references to bony landmarks and inclusion of the para-aortic and inferior obturator nodal regions.

METHODS AND MATERIALS

An international consensus guideline working group discussed modifications of the current atlas and areas of controversy. A document was prepared to assist in contouring definitions. A sample case abdominopelvic computed tomographic image was made available, on which experts contoured targets. Targets were analyzed for consistency of delineation using an expectation-maximization algorithm for simultaneous truth and performance level estimation with kappa statistics as a measure of agreement between observers.

RESULTS

Sixteen participants provided 13 sets of contours. Participants were asked to provide separate contours of the following areas: vaginal cuff, obturator, internal iliac, external iliac, presacral, common iliac, and para-aortic regions. There was substantial agreement for the common iliac region (sensitivity 0.71, specificity 0.981, kappa 0.64), moderate agreement in the external iliac, para-aortic, internal iliac and vaginal cuff regions (sensitivity 0.66, 0.74, 0.62, 0.59; specificity 0.989, 0.966, 0.986, 0.976; kappa 0.60, 0.58, 0.52, 0.47, respectively), and fair agreement in the presacral and obturator regions (sensitivity 0.55, 0.35; specificity 0.986, 0.988; kappa 0.36, 0.21, respectively). A 95% agreement contour was smoothed and a final contour atlas was produced according to consensus.

CONCLUSIONS

Agreement among the participants was most consistent in the common iliac region and least in the presacral and obturator nodal regions. The consensus volumes formed the basis of the updated NRG/RTOG Oncology postoperative atlas. Continued patterns of recurrence research are encouraged to refine these volumes.

Phase 0 Radiopharmaceutical-Agent Clinical Development

The evaluation of antibody-targeted or peptide-targeted radiopharmaceuticals as monotherapy or in oncological drug combinations requires programmatic collaboration within the National Cancer Institute (NCI) clinical trial enterprise. Phase 0 trials provide a flexible research platform for the study of radiopharmaceutical–drug pharmacokinetics, radiation dosimetry, biomarkers of DNA damage response modulation, and pharmacodynamic benchmarks predictive of therapeutic success. In this article, we discuss a phase 0 clinical development approach for human antibody-targeted or peptide-targeted radiopharmaceutical–agent combinations. We expect that early-phase radiopharmaceutical–agent combination trials will become a more tactical and more prevalent part of radiopharmaceutical clinical development in the near-term future for the NCI Cancer Therapy Evaluation Program.

Bone Fracture Incidence After Androgen Deprivation Therapy-Investigational Agents: Results From Cancer Therapy Evaluation Program-Sponsored Early Phase Clinical Trials 2006-2013

Introduction: Androgen deprivation therapy (ADT) is a primary treatment option for patients diagnosed with locally advanced-stage or metastatic prostate cancer. Androgen deprivation can be achieved either by radical orchiectomy or by medical castration using a gonadotropin-releasing hormone agonist. ADT has been linked to an initial 12-month loss of bone mineral density, a risk factor for weight-bearing bone fracture, and therefore, a confounding hazard for adverse event when patients are enrolled on early phase trials. To better understand the frequency of ADT-investigational agent-related bone fracture, we conducted a retrospective study of National Cancer Institute Cancer Therapy Evaluation Program (CTEP)-sponsored early phase trials to determine the number of fractures observed among enrolled prostate cancer patients. Patients and Methods: 464 locally advanced-stage or metastatic prostate cancer patients were identified among seven ADT-investigational agent trials conducted between 2006 and 2013. Demographic, co-morbidity, treatment, and adverse event variables were abstracted from CTEP databases and descriptive statistics were used. Results: 464 men had a median age of 64 years, were mostly white (90%), and had a performance status of 0 or 1 (98%). The number of new bone fractures occurring on or after ADT-investigational agent treatment was very low (4.6 per 1000 person-years). The median pretrial prostate specific antigen level was 29 ng/mL and most men (71%) had prostate cancer histopathology Gleason 7 score or higher. In these trials, 43 percent of men had bone only and 35 percent had bone and visceral metastatic disease. The most frequent grade 1 or 2 adverse events were fatigue (36%), hot flashes (27%), and anemia (17%). Grade 3 or higher adverse events were rare, with hypertension (3%) and hyperglycemia (3%) observed. Conclusions: Identifying bone health factors may still be relevant in selected early phase ADT-investigational agent trial patients, emphasizing the need for improved methods for capturing baseline bone health and studying ADT-investigational agent and concurrent medication interactions on bone health.

Prognostic and predictive factors associated with ipilimumab-related adverse events: a retrospective analysis of 11 NCI-sponsored phase I clinical trials

BACKGROUND

We review factors impacting ipilimumab-associated adverse events through the experience from National Cancer Institute (NCI)-sponsored phase I immunotherapy clinical trials.

MATERIALS AND METHODS

Attributable ipilimumab-related adverse events from NCI-sponsored phase I immunotherapy clinical trials were queried retrospectively by anonymized patient experience reports for observed adverse events like decreased hematological cell counts, blood electrolytes or proteins, or reduced patient performance status. The prevalence of ipilimumab-related toxicity was associated by patient to the duration of ipilimumab exposure, radiographic responses, progression-free survival, and overall survival.

RESULTS

373 patients from 11 phase 1 ipilimumab clinical trials were analyzed. Patients experiencing at least one grade 3 or 4 adverse event associated with observed radiographic response were included. The average number of grade 3/4 adverse events in responders was 1.167 versus 0.645 in non-responders (p = 0.001). Patient performance status did not significantly impact observed toxicity grade. Pretherapy lymphocyte count or chemistries were not associated with ipilimumab-associated toxicity. The number of agents combined with ipilimumab on trial was associated with average number of grade 3/4 toxicities-ipilimumab monotherapy (0.631) versus ipilimumab + 1 agent (0.877) versus ipilimumab + 2 agents (1.408) (p = 0.014). Number of low grade (grade 1/2) toxicities was associated with duration of treatment, Pearson correlation coefficient r = 0.456 (p < 0.0001); whereas the number of high grade (grade 3/4) toxicities was not, r = 0.032 (p = 0.546).

CONCLUSIONS

Ipilimumab-attributed grade 3/4 toxicity was associated with therapeutic response. The number of co-administered agents added to ipilimumab significantly raised the likelihood of toxicity. Extended duration of treatment increased the incidence of low but not high-grade toxicity.

Immunotherapy for Medulloblastoma: Current Perspectives

Background

Immune-mediated therapies have transformed the treatment of metastatic melanoma and renal, bladder, and both small and non-small cell lung carcinomas. However, immunotherapy is yet to demonstrate dramatic results in brain tumors like medulloblastoma for a variety of reasons. Recent pre-clinical and early phase human trials provide encouraging results that may overcome the challenges of central nervous system (CNS) tumors, which include the intrinsic immunosuppressive properties of these cancers, a lack of antigen targets, antigenic variability, and the immune-restrictive site of the CNS. These studies highlight the growing potential of immunotherapy to treat patients with medulloblastoma, a disease that is a frequent cause of morbidity and mortality to children and young adults.

Methods

We conducted an inclusive review of the PubMed-indexed literature and studies listed in clinicaltrials.gov using combinations of the keywords medulloblastoma, immunotherapy, CNS tumors, brain tumors, vaccines, oncolytic virus, natural killer, and CAR T to identify trials evaluating immunotherapy in preclinical experiments or in patients with medulloblastoma. Given a limited number of investigations using immunotherapy to treat patients with medulloblastoma, 24 studies were selected for final analysis and manuscript citation.

Results

This review presents results from pre-clinical studies in medulloblastoma cell lines, animal models, and the limited trials involving human patients.

Conclusion

From our review, we suggest that cancer vaccines, oncolytic viral therapy, natural killer cells, and CAR T therapy hold promise against the innate immunosuppressive properties of medulloblastoma in order to prolong survival. There is an unmet need for immunotherapy regimens that target overexpressed antigens in medulloblastoma tumors. We advocate for more combination treatment clinical trials using conventional surgical and radiochemotherapy approaches in the near-term clinical development.

Single-Arm Phase II Trials of Combination Therapies: A Review of the CTEP Experience 2008-2017

Designing and interpreting single-arm phase II trials of combinations of agents is challenging because it can be difficult, based on historical data, to identify levels of activity for which the combination would be worth pursuing. We identified Cancer Therapy Evaluation Program single-arm combination trials that were activated in 2008-2017 and tabulated their design characteristics and results. Positive trials were evaluated as to whether they provided credible evidence that the combination was better than its constituents. A total of 125 trials were identified, and 120 trials had results available. Twelve had designs where eligible patients were required to be resistant or refractory to all but one element of the combination. Only 17.8% of the 45 positive trials were deemed to provide credible evidence that the combination was better than its constituents. Of the 10 positive trials with observed rates 10 percentage points higher than their upper (alternative hypothesis) targets, only five were deemed to provide such credible evidence. Many trials were definitively negative, with observed clinical activity at or below their lower (null hypothesis) targets. Ideally, use of single-arm combination trials should be restricted to settings where each agent is known to have minimal monotherapy activity (and a randomized trial is infeasible). In these settings, an observed signal is attributable to synergy and thus could be used to decide whether the combination is worth pursuing. In other settings, credible evidence can still be obtained if the observed activity is much higher than expected, but experience suggests that this is a rare occurrence.

Survey of current practices from an international task force for gynecological stereotactic ablative radiotherapy

Background

Stereotactic Ablative Radiotherapy (SABR) is an effective treatment that improves local control for many tumours. However, the role of SABR in gynecological cancers (GYN) has not been well-established. We hypothesize that there exists considerable variation in GYN-SABR practice and technique. The goal of this study is to describe clinical and technical factors in utilization of GYN-SABR among 11 experienced radiation oncologists.

Materials and methods

A 63 question survey on GYN-SABR was sent to 11 radiation oncologists (5 countries) who have published original research, conducted trials or have an established program at their institutions. Responses were combined and analyzed at a central institution.

Results

Most respondents indicated that salvage therapy (non-irradiated or re-irradiated field) for nodal (81%) and primary recurrent disease (91%) could be considered standard options for SABR in the setting of inability to administer brachytherapy. All other indications should be considered on clinical trials. Most would not offer SABR as a boost in primary treatment off-trial without absolute contraindications to brachytherapy. Multi-modality imaging is often (91%) used for planning including PET, CT contrast and MRI. There is a wide variation for OAR tolerances however small bowel is considered the dose-limiting structure for most experts (91%). Fractionation schedules range from 3 to 6 fractions for nodal/primary definitive and boost SABR.

Conclusions

Although SABR has become increasingly standard in other oncology disease sites, there remains a wide variation in both clinical and technical factors when treating GYN cancers. Nodal and recurrent disease is considered a potential indication for SABR whereas other indications should be offered on clinical trials. This study summarizes SABR practices among GYN radiation oncologists while further studies are needed to establish consensus guidelines for GYN-SABR treatment.

Randomized Phase II Trial of Triapine-Cisplatin-Radiotherapy for Locally Advanced Stage Uterine Cervix or Vaginal Cancers

Uterine cervix or vaginal cancers have inherent overactivity of ribonucleotide reductase (RNR), making these cancers rational targets for therapy based on interruption of cisplatin-radiotherapy-induced DNA damage repair. We conducted a pilot, open-label randomized phase II trial to evaluate the efficacy and safety of cisplatin-radiotherapy with or without triapine, a small molecule with RNR-inhibitory activity, in patients with advanced-stage uterine cervix or vaginal cancers (NCT01835171), as a lead in to a randomized phase III study (NCT02466971). A total of 26 women were randomly assigned to receive 6 weeks of daily radiotherapy followed by brachytherapy (80 Gy) and once-weekly cisplatin (40 mg m⁻²)—with or without three-times weekly intravenous triapine (25 mg m⁻²)—in one 56-days cycle. Primary end points were metabolic complete response by positron emission tomography and safety. Additional end points included the rate of clinical response, rate of methemoglobinemia, and progression-free survival. The addition of triapine to cisplatin-radiotherapy improved the rate of metabolic complete response from 69 to 92% (P = 0.32) and raised the 3-year progression-free survival estimate from 77 to 92% (hazard ratio for progression, 0.30; P = 0.27). The most frequent grade 3 or 4 adverse events in either treatment group included reversible leukopenia, neutropenia, fatigue, or electrolyte abnormalities. No significant differences were seen between the two groups in the rate of adverse events. Symptomatic methemoglobinemia was not encountered after triapine infusion. In conclusion, the addition of triapine to cisplatin-radiotherapy improved the rate of metabolic complete response in patients with advanced-stage uterine cervix or vaginal cancers without significant toxicity. A phase III trial adequately powered to evaluate progression-free and overall survival is underway (NCT02466971).

Clinical Outcome Assessments Toolbox for Radiopharmaceuticals

For nearly 40 years, the U.S. National Cancer Institute (NCI) has funded health-related quality-of-life (HRQOL) and symptom management in oncology clinical trials as a method for including a cancer patient's experience during and after treatment. The NCI's planned scope for HRQOL, symptom and patient-reported outcomes management research is explained as it pertains to radiopharmaceutical clinical development. An effort already underway to support protocol authoring via an NCI Cancer Therapy Evaluation Program (CTEP) Centralized Protocol Writing Service (CPWS) is described as this service aids incorporation of HRQOL, symptom and patient-reported outcomes management research into sponsored protocols.

Defining and targeting wild-type BRCA high-grade serous ovarian cancer: DNA repair and cell cycle checkpoints

Introduction: Molecular analyzes including molecular descriptor/phenotype interactions have led to better characterization of epithelial ovarian cancer patients, including a definition of a BRCA wild-type (BRCAwt) phenotype. Understanding how and when to use agents targeted against dependent BRCAwt pathways or other molecular events at disease progression is an important translational and therapeutic direction in ovarian cancer research. Areas covered: In this overview, we provide definitions and descriptions of a BRCAwt genotype and phenotype. We discuss novel investigational drugs that hold promise for the treatment of BRCAwt ovarian cancer, including inhibitors of poly(ADP-ribose) polymerase, ribonucleotide reductase, DNA protein kinase-catalytic subunit, ataxia-telangiectasia-mutated kinase (ATM), ataxia-telangiectasia mutated and Rad3-related kinase (ATR), CHK 1/2, cyclin kinases, glutaminase-1, WEE1 kinase, as well as tumor microenvironment and angiogenesis inhibitors. This article explores the known and the emerging areas of clinical research on patients with BRCAwt ovarian cancer. Expert opinion: Discovery of molecular changes tied to annotated disease information, along with an expanding array of pathway targets and targeted therapeutic agents, creates optimism and opportunity for women with ovarian cancer. Using precision oncology approaches, clinical researchers are, and will be, poised to select more effective treatments for ovarian cancer patients.

Abstract 3870: The addition of CB-839 to temozolomide significantly reduces glioma aspartate and glutamate in an IDH mutated patient derived glioma xenograft model

Background: IDH mutated gliomas are critically dependent on glutaminase for glutamate biosynthesis. CB-839 is a novel glutaminase-1 inhibitor which has demonstrated efficacy in both genetically engineered and patient derived IDH mutated glioma cells, especially in combination with radiation. These preclinical studies evaluate the pharmacodynamic and pharmacokinetic impact of combining CB-839 with TMZ in patient derived xenograft (PDX) glioma models.

Methods: GBM164 is a PDX model derived from an IDH1 mutant, 1p/19q non-codeleted glioma. D- and L-2HG levels in untreated GBM164 tumors were compared to GBM6 tumors (IDH wildtype glioma PDX) by GC/MS. Athymic nude mice bearing GBM164 flank tumors were treated with CB-839 (200 mg/kg PO BID x 9 doses) and/or temozolomide (50 mg/kg PO daily x 5 doses) and sacrificed four hours after the last dose to harvest plasma, normal brain and flank tumor. Tumor metabolomics were assessed by GC/MS. DNA damage signaling in tumors was assessed by Western blotting for KAP1 / Chk1 / Chk2 phosphorylation and H2AX / Rad51. Tumor, plasma and brain pharmacokinetics were assessed by LC/MS/MS.

Results: Total 2HG levels in GBM164 were 18-fold higher than GBM6. CB-839 monotherapy reduced tumor glutamate (18% reduction, p = 0.15) and aspartate (30% reduction, p = 0.06) when compared to vehicle, however these changes did not reach statistical significance. The combination of CB-839 and TMZ more significantly reduced both tumor glutamate (30% reduction, p = 0.03) and aspartate (34% reduction, p &lt; 0.001) when compared to TMZ monotherapy. CB-839 did not significantly increase DNA damage compared to vehicle, and the combination of CB-839 and TMZ did not significantly increase DNA damage compared to TMZ monotherapy. The mean tumor: plasma ratios of CB-839 concentrations were 0.68 and 0.58 in mice treated with CB-839 monotherapy and CB-839/TMZ, respectively. The mean brain: plasma ratios of CB-839 concentrations were 0.07 and 0.12 in mice treated with CB-839 monotherapy and CB-839/TMZ, respectively.

Conclusion: The addition of CB-839 to TMZ significantly reduces glioma aspartate and glutamate in an IDH1 mutant PDX glioma model, without any impact on DNA damage. Survival studies are in progress to assess the efficacy of CB-839 when used in combination with RT and/or TMZ.

Citation Format: Sani Haider Kizilbash, Danielle M. Burgenske, Samuel McBrayer, Sandhya Devarajan, Shiv K. Gupta, Taro Hitosugi, Lihong He, Mark A. Schroeder, Brett L. Carlson, Marina Gelman, Charles A. Kunos, Joel M. Reid, Alex A. Adjei, Jann N. Sarkaria. The addition of CB-839 to temozolomide significantly reduces glioma aspartate and glutamate in an IDH mutated patient derived glioma xenograft model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3870.

Leveraging National Cancer Institute Programmatic Collaboration for Single Radiopharmaceutical Drug Master Files

Targeted radiopharmaceutical conjugates intended for therapeutic use often are made of three key components, a decaying radionuclide, a chemical chelator/linker, and a targeted molecular entity. The National Cancer Institute (NCI) Experimental Therapeutics Program has accepted four radiopharmaceutical drug products so far that fit the targeted radiopharmaceutical conjugate class. As the NCI sharpens its thinking about its role as an investigational new drug sponsor for radiopharmaceuticals in clinical development, it has considered the relative merits of modular radiopharmaceutical drug master files. Here, the NCI provides its perspective on modular radiopharmaceutical drug master files as it initiates a clinical development program for such agents and further organizes its radiopharmaceutical Small Business Innovation Research portfolio.

Radiopharmaceuticals for Persistent or Recurrent Uterine Cervix Cancer

Uterine cervix cancers pose therapeutic challenges because of an overactive ribonucleotide reductase, which provides on-demand deoxyribonucleotides for DNA replication or for a DNA damage repair response. Ribonucleotide reductase overactivity bestows cancer cell resistance to the effects of radiotherapy and chemotherapy used to treat disease; but nevertheless, this same biologic overexpression provides opportune vulnerabilities relatively specific to uterine cervix cancers for new therapeutic strategies to take advantage. The discovery of human epidermal growth factor receptor 2 (ErbB2 or HER2) overexpression on metastatic uterine cervix cancer cells provides an opportunity for clinical trials of targeted radiopharmaceuticals in combination with DNA damage response modifying drugs. The National Cancer Institute's clinical trial infrastructure and its experimental therapeutics portfolio can now offer clinical trial evaluation of molecularly-targeted and tolerated radiopharmaceutical-drug combinations for women with persistent or recurrent metastatic uterine cervix cancer. This article discusses the current thinking of the National Cancer Institute in regard to attractive radiopharmaceutical strategies for this disease and others.

Leveraging National Cancer Institute Programmatic Collaboration for Uterine Cervix Cancer Brachytherapy in Puerto Rico After Hurricane Maria

Evaluating the impact of natural disasters on cancer patients is vital to the recovery of cancer treatment services and infrastructure. In September 2017, Hurricane Maria demolished the gynecologic cancer service in the United States territory of Puerto Rico and its outreach to the territory of the Virgin Islands of the United States. Patient access to brachytherapy for uterine cervix cancer patients can be difficult to measure in the aftermath of a hurricane. The United States National Cancer Institute (NCI) surveyed gynecologic radiation medicine providers on the island to generate an independent perspective on gynecologic brachytherapy service recovery after the hurricane. Providers were asked about patient displacement, infrastructure loss, and reestablishment of cancer treatment. Here, the NCI provides its perspective on recovery of these services as it relates to its pre-hurricane investment for staff in the NCI Community Oncology Research Program.

Radiopharmaceuticals for Relapsed or Refractory Ovarian Cancers

Targeted radiopharmaceuticals for therapeutic use deliver radionuclides directly to tumor anywhere in the body, and therefore, have renewed interest for clinical development in women with disseminated chemorefractory ovarian cancers. About two in every five women with advanced stage ovarian cancer outlive their disease after the first treatment phase, with the rest rendered incurable due to the chemorefractory nature of their disease. The National Cancer Institute (NCI) Cancer Therapy Evaluation Program conducted 67 phase I or phase Ib trials among women with relapsed or refractory ovarian cancer between 1989 and 2017 in an effort to uncover tolerable and effective drug combinations intended to increase survival rates. None of these early clinical development phase trials involved radiopharmaceuticals. Here, the NCI provides its perspective on targeted radiopharmaceutical conjugates alone or in combination with its experimental therapeutics portfolio for women with relapsed or refractory ovarian cancer. An infrastructure build for Federal radiopharmaceutical medical monitoring and adverse event reporting has begun.

Radiopharmaceuticals for Relapsed or Refractory Leukemias

Radiopharmaceuticals, meaning drugs that hold a radionuclide intended for use in cancer patients for treatment of their disease or for palliation of their disease-related symptoms, have gained new interest for clinical development in adult patients with relapsed or refractory leukemia. About one-third of adult patients outlive their leukemia, with the remainder unable to attain complete remission status following the first phase of treatment due to refractory bone marrow or blood residual microscopic disease. The National Cancer Institute (NCI) Cancer Therapy Evaluation Program conducted 49 phase 1-1b trials in adult patients with leukemia between 1986 and 2017 in an effort to discover tolerated and effective therapeutic drug combinations intended to improve remission and mortality rates. None of these trials involved radiopharmaceuticals. In this article, the NCI perspective on the challenges encountered in and on the future potential of radiopharmaceuticals alone or in combination for adult patients with relapsed or refractory leukemia is discussed. An effort is underway already to build-up the NCI's clinical trial enterprise infrastructure for radiopharmaceutical clinical development.

A Phase I Evaluation of Extended Field Radiation Therapy With Concomitant Cisplatin Chemotherapy Followed by Paclitaxel and Carboplatin Chemotherapy in Women With Cervical Carcinoma Metastatic to the Para-aortic Lymph Nodes: An NRG Oncology/Gynecologic Oncology Group Study

BACKGROUND

Chemo-radiation (chemoRT) has improved the overall survival for locally advanced cervical cancer (LACC) though women whose disease involves the para-aortic nodes (PAN) experience recurrence rates and worse survival outcomes compared to those without PAN involvement. This Phase I study determined if additional cycles of systemic chemotherapy could be safely added to extended field chemoRT in this population of patients.

METHODS

Women with LACC and documented positive PAN were eligible for treatment. All women were treated with extended field radiation and brachytherapy and concurrent cisplatin 40 mg/m² weekly for six weeks. Four to six weeks after completion of chemoRT, patients were treated with four cycles of paclitaxel 135 mg/m² and escalating doses of carboplatin (Dose Level (DL) 1 = AUC 4, DL2 = AUC 5).

RESULTS

Eleven women were entered on study and 9 were evaluable for dose limiting toxicities (DLT). Two women (1 in each of 2 DLs) did not complete chemoRT and so were not evaluable for DLT. Three women completed all 10 cycles at DL 1 with no DLTs. Six women were then treated at DL 2. For the 10 patients evaluable for response, the ORR was 60% (CR + PR). PFS and OS at 12 months were 60% and 90%, respectively. The predominant grade 3 or 4 acute toxicities were hematologic. There were no grade 5 events.

CONCLUSION

Extended field chemoRT followed by paclitaxel 135 mg/m² and carboplatin AUC 5 is feasible in women with LACC and positive PAN.

National Cancer Institute Programmatic Collaboration for Investigational Radiopharmaceuticals

Radiopharmaceutical therapies have provided an attractive therapeutic approach since the introduction of ¹³¹I to treat thyroid cancer. New insights in cancer biology and radiochemistry have brought radiopharmaceuticals to the leading edge of oncology clinical research. National Cancer Institute (NCI) programs watch for new radiopharmaceutical breakthroughs that should be used to treat patients with unmet therapeutic needs. Such efforts occur through leveraged partnerships between NCI's Cancer Therapy Evaluation Program and its Radiation Research Program. If groundbreaking discoveries are made, NCI pulls together clinician scientists to design novel radiopharmaceutical phase I and II monotherapy or combination trials. The specific infrastructure needs, such as radiopharmaceutical dosimetry and treatment planning, demand new programmatic workflow and regulatory oversight. This article discusses a modern approach to the development of radiopharmaceutical therapies in the era of personalized medicine.

Triapine Radiochemotherapy in Advanced Stage Cervical Cancer

Clinical ribonucleotide reductase (RNR) inhibitors have reinvigorated enthusiasm for radiochemotherapy treatment of patients with regionally advanced stage cervical cancers. About two-thirds of patients outlive their cervical cancer (1), even though up to half of their tumors retain residual microscopic disease (2). The National Cancer Institute Cancer Therapy Evaluation Program conducted two prospective trials of triapine–cisplatin–radiation to improve upon this finding by precisely targeting cervical cancer’s overactive RNR. Triapine’s potent inactivation of RNR arrests cells at the G1/S cell cycle restriction checkpoint and enhances cisplatin–radiation cytotoxicity. In this article, we provide perspective on challenges encountered in and future potential of clinical development of a triapine–cisplatin–radiation combination for patients with regionally advanced cervical cancer. New trial results and review presented here suggest that a triapine–cisplatin–radiation combination may offer molecular cell cycle target control to maximize damage in cancers and to minimize injury to normal cells. A randomized trial now accrues patients with regionally advanced stage cervical cancer to evaluate triapine’s contribution to clinical benefit after cisplatin–radiation (clinicaltrials.gov, NCT02466971).

Leveraging National Cancer Institute Programmatic Collaboration for Uterine Cervix Cancer Patient Accrual in Puerto Rico

Women in the U.S. Commonwealth of Puerto Rico (PR) have a higher age-adjusted incidence rate for uterine cervix cancer than the U.S. mainland as well as substantial access and economic barriers to cancer care. The National Cancer Institute (NCI) funds a Minority/Underserved NCI Community Oncology Research Program in PR (PRNCORP) as part of a national network of community-based health-care systems to conduct multisite cancer clinical trials in diverse populations. Participation by the PRNCORP in NCI’s uterine cervix cancer clinical trials, however, has remained limited. This study reports on the findings of an NCI site visit in PR to assess barriers impeding site activation and accrual to its sponsored gynecologic cancer clinical trials. Qualitative, semi-structured individual, and group interviews were conducted at six PRNCORP-affiliated locations to ascertain: long-term trial accrual objectives; key stakeholders in PR that address uterine cervix cancer care; key challenges or barriers to activating and to enrolling patients in NCI uterine cervix cancer treatment trials; and resources, policies, or procedures in place or needed on the island to support NCI-sponsored clinical trials. An NCI-sponsored uterine cervix cancer radiation–chemotherapy intervention clinical trial (NCT02466971), already activated on the island, served as a test case to identify relevant patient accrual and site barriers. The site visit identified five key barriers to accrual: (1) lack of central personnel to coordinate referrals for treatment plans, medical tests, and medical imaging across the island’s clinical trial access points; (2) patient insurance coverage; (3) lack of a coordinated brachytherapy schedule at San Juan-centric service providers; (4) limited credentialed radiotherapy machines island-wide; and (5) too few radiology medical physicists tasked to credential trial-specified positron emission tomography scanners island-wide. PR offers a unique opportunity to study overarching and tactical strategies for improving accrual to NCI-sponsored gynecologic cancer clinical trials. Interview findings support adding and re-tasking personnel for coordinated trial-eligible patient referral, accrual, and treatment.

Incorporating Radiation Oncology into Immunotherapy: proceedings from the ASTRO-SITC-NCI immunotherapy workshop

Radiotherapy (RT) has been a fundamental component of the anti-cancer armamentarium for over a century. Approximately half of all cancer patients are treated with radiotherapy during their disease course. Over the two past decades, there has been a growing body of preclinical evidence supporting the immunomodulatory effects of radiotherapy, particularly when combined with immunotherapy, but only anecdotal clinical examples existed until recently. The renaissance of immunotherapy and the recent U.S. Food and Drug Administration (FDA) approval of several immune checkpoint inhibitors (ICIs) and other immuno-oncology (IO) agents in multiple cancers provides the opportunity to investigate how localized radiotherapy can induce systemic immune responses. Early clinical experiences have demonstrated feasibility of this approach but additional preclinical and clinical investigation is needed to understand how RT and immunotherapy can be optimally combined.

To address questions that are critical to successful incorporation of radiation oncology into immunotherapy, the American Society for Radiation Oncology (ASTRO), the Society for Immunotherapy of Cancer (SITC) and the National Cancer Institute (NCI) organized a collaborative scientific workshop, Incorporating Radiation Oncology into Immunotherapy, that convened on June 15 and 16 of 2017 at the Natcher Building, NIH Campus in Bethesda, Maryland. This report summarizes key data and highlights from each session.

Phase I Trial of Triapine-Cisplatin-Paclitaxel Chemotherapy for Advanced Stage or Metastatic Solid Tumor Cancers

Ribonucleotide reductase (RNR) is an enzyme involved in the de novo synthesis of deoxyribonucleotides, which are critical for DNA replication and DNA repair. Triapine is a small-molecule RNR inhibitor. A phase I trial studied the safety of triapine in combination with cisplatin–paclitaxel in patients with advanced stage or metastatic solid tumor cancers in an effort to capitalize on disrupted DNA damage repair. A total of 13 patients with various previously treated cancers were given a 96-h continuous intravenous (i.v.) infusion of triapine (40–120 mg/m²) on day 1, and then 3-h i.v. paclitaxel (80 mg/m²) followed by 1-h i.v. cisplatin (50–75 mg/m²) on day 3. This combination regimen was repeated every 21 days. The maximum tolerated dose (MTD) for each agent was identified to be triapine (80 mg/m²), cisplatin (50 mg/m²), and paclitaxel (80 mg/m²). Common grade 3 or 4 toxicities included reversible anemia, leukopenia, thrombocytopenia, or electrolyte abnormalities. The combination regimen of triapine–cisplatin–paclitaxel resulted in no objective responses; however, five (83%) of six patients treated at the MTD had stable disease between 1 and 8 months duration. This phase I study showed that the combination regimen of triapine–cisplatin–paclitaxel was safe and provides a rational basis for a follow-up phase II trial to evaluate efficacy and progression-free survival in women with metastatic or recurrent uterine cervix cancer.

Phase I trial of daily triapine in combination with cisplatin chemotherapy for advanced-stage malignancies

PURPOSE

Advanced-stage malignancies have increased deoxyribonucleotide demands in DNA replication and repair, making deoxyribonucleotide supply a potential exploitable target for therapy based on ribonucleotide reductase (RNR) inhibition.

METHODS

A dose-finding phase I trial was conducted of intravenous (i.v.) triapine, a small-molecule RNR inhibitor, and cisplatin chemotherapy in patients with advanced-stage solid tumor malignancies. Patients received dose-finding levels of i.v. triapine (48-96 mg/m²) and i.v. cisplatin (20-75 mg/m²) on 1 of 3 different schedules. The primary endpoint was to identify the maximum tolerated dose of a triapine-cisplatin combination. Secondary endpoints included the rate of triapine-cisplatin objective response and the pharmacokinetics and bioavailability of a single oral triapine dose. (Clinicaltrials.gov number, NCT00024323).

RESULTS

The MTD was 96 mg/m² triapine daily days 1-4 and 75 mg/m² cisplatin split over day 2 and day 3. Frequent grade 3 or 4 adverse events included fatigue, dyspnea, leukopenia, thrombocytopenia, and electrolyte abnormalities. No objective responses were observed; 5 (50%) of 10 patients treated at the MTD had stable disease. Pharmacokinetics indicated an oral triapine bioavailability of 88%.

CONCLUSIONS

The triapine-cisplatin combination may be given safely in patients with advanced-stage solid tumor malignancies. On the basis of these results, a phase I trial adequately powered to evaluate oral triapine bioavailability in women with advanced-stage uterine cervix or vulvar cancers is underway.

Impact of nurse navigation on timeliness of diagnostic medical services in patients with newly diagnosed lung cancer

BACKGROUND

The Summa Cancer Institute in Akron, Ohio, sought to improve access to and the timeliness of lung cancer care by hiring an oncology-certified nurse navigator. The nurse navigator was charged with coordinating diagnostic procedures and specialty oncology consultations, and with facilitating a multidisciplinary thoracic oncology tumor board.

OBJECTIVE

To test the hypothesis that nurse navigation would improve the timeliness of and access to diagnostic medical services among men and women with newly diagnosed lung cancer.

METHODS

A conducted a retrospective review of 460 patients with lung cancer to evaluate access to care and the timeliness of the care received in the non-navigated and nurse-navigated cohorts.

RESULTS

During December 2009-September 2013, the time between the suspicion of cancer on chest X-ray to treatment was 64 days. During October 2013-March 2014, the nurse navigator helped reduce that timespan to 45 days (𝑃 < .001).

LIMITATIONS

Long-term follow-up on clinical outcomes remains premature.

CONCLUSION

This finding attests to the successful implementation of nurse navigation to improve access and timeliness of lung cancer care in a community oncology practice.

Radiation-Therapeutic Agent Clinical Trials: Leveraging Advantages of a National Cancer Institute Programmatic Collaboration

A number of oncology phase II radiochemotherapy trials with promising results have been conducted late in the overall experimental therapeutic agent development process. Accelerated development and approval of experimental therapeutic agents have stimulated further interest in much earlier radiation-agent studies to increase the likelihood of success in phase III trials. To sustain this interest, more forward-thinking preclinical radiobiology experimental designs are needed to improve discovery of promising radiochemotherapy plus agent combinations for clinical trial testing. These experimental designs should better inform next-step radiation-agent clinical trial dose, schedule, exposure, and therapeutic effect. Recognizing the need for a better strategy to develop preclinical data supporting radiation-agent phase I or II trials, the National Cancer Institute (NCI)-Cancer Therapy Evaluation Program (CTEP) and the NCI-Molecular Radiation Therapeutics Branch of the Radiation Research Program have partnered to promote earlier radiobiology studies of CTEP portfolio agents. In this Seminars in Radiation Oncology article, four key components of this effort are discussed. First, we outline steps for accessing CTEP agents for preclinical testing. Second, we propose radiobiology studies that facilitate transition from preclinical testing to early phase trial activation. Third, we navigate steps that walk through CTEP agent strategic development paths available for radiation-agent testing. Fourth, we highlight a new NCI-sponsored cooperative agreement grant supporting in vitro and in vivo radiation-CTEP agent testing that informs early phase trial designs. Throughout the article, we include contemporary examples of successful radiation-agent development initiatives.

Dynamic Lung Tumor Tracking for Stereotactic Ablative Body Radiation Therapy

Physicians considering stereotactic ablative body radiation therapy (SBRT) for the treatment of extracranial cancer targets must be aware of the sizeable risks for normal tissue injury and the hazards of physical tumor miss. A first-of-its-kind SBRT platform achieves high-precision ablative radiation treatment through a combination of versatile real-time imaging solutions and sophisticated tumor tracking capabilities. It uses dual-diagnostic kV x-ray units for stereoscopic open-loop feedback of cancer target intrafraction movement occurring as a consequence of respiratory motions and heartbeat. Image-guided feedback drives a gimbaled radiation accelerator (maximum 15 x 15 cm field size) capable of real-time ±4 cm pan-and-tilt action. Robot-driven ±60° pivots of an integrated ±185° rotational gantry allow for coplanar and non-coplanar accelerator beam set-up angles, ultimately permitting unique treatment degrees of freedom. State-of-the-art software aids real-time six dimensional positioning, ensuring irradiation of cancer targets with sub-millimeter accuracy (0.4 mm at isocenter). Use of these features enables treating physicians to steer radiation dose to cancer tumor targets while simultaneously reducing radiation dose to normal tissues. By adding respiration correlated computed tomography (CT) and 2-[(18)F] fluoro-2-deoxy-ᴅ-glucose ((18)F-FDG) positron emission tomography (PET) images into the planning system for enhanced tumor target contouring, the likelihood of physical tumor miss becomes substantially less. In this article, we describe new radiation plans for the treatment of moving lung tumors.

Phase I Trial of Carboplatin and Gemcitabine Chemotherapy and Stereotactic Ablative Radiosurgery for the Palliative Treatment of Persistent or Recurrent Gynecologic Cancer

Background

We conducted a phase I trial to determine the safety of systemic chemotherapy prior to abdominopelvic robotic stereotactic ablative radiotherapy (SABR) in women with persistent or recurrent gynecologic cancers.

Methods

Patients were assigned to dose-finding cohorts of day 1 carboplatin (AUC 2 or 4) and gemcitabine (600 or 800 mg/m²) followed by day 2 to day 4 Cyberknife SABR (8 Gy × three consecutive daily doses). Toxicities were graded prospectively by common terminology criteria for adverse events, version 4.0. SABR target and best overall treatment responses were recorded according to response evaluation criteria in solid tumors, version 1.1.

Findings

The maximum tolerated dose of chemotherapy preceding SABR was carboplatin AUC 4 and gemcitabine 600 mg/m². One patient experienced manageable, dose-limiting grade 4 neutropenia, grade 4 hypokalemia, and grade 3 nausea attributed to study treatment. One patient had a late grade 3 rectovaginal fistula 16 months after trial therapy. Among 28 SABR targets, 22 (79%) showed a partial response and 6 (21%) remained stable.

Interpretation

Systemic chemotherapy may be given safely prior to abdominopelvic robotic SABR with further investigation warranted.

Comparison and consensus guidelines for delineation of clinical target volume for CT- and MR-based brachytherapy in locally advanced cervical cancer

OBJECTIVE

To create and compare consensus clinical target volume (CTV) contours for computed tomography (CT) and 3-Tesla (3-T) magnetic resonance (MR) image-based cervical-cancer brachytherapy.

METHODS AND MATERIALS

Twenty-three experts in gynecologic radiation oncology contoured the same 3 cervical cancer brachytherapy cases: 1 stage IIB near-complete response (CR) case with a tandem and ovoid, 1 stage IIB partial response (PR) case with tandem and ovoid with needles, and 1 stage IB2 CR case with a tandem and ring applicator. The CT contours were completed before the MRI contours. These were analyzed for consistency and clarity of target delineation using an expectation maximization algorithm for simultaneous truth and performance level estimation (STAPLE), with κ statistics as a measure of agreement between participants. The conformity index was calculated for each of the 6 data sets. Dice coefficients were generated to compare the CT and MR contours of the same case.

RESULTS

For all 3 cases, the mean tumor volume was smaller on MR than on CT (P<.001). The κ and conformity index estimates were slightly higher for CT, indicating a higher level of agreement on CT. The Dice coefficients were 89% for the stage IB2 case with a CR, 74% for the stage IIB case with a PR, and 57% for the stage IIB case with a CR.

CONCLUSION

In a comparison of MR-contoured with CT-contoured CTV volumes, the higher level of agreement on CT may be due to the more distinct contrast medium visible on the images at the time of brachytherapy. MR at the time of brachytherapy may be of greatest benefit in patients with large tumors with parametrial extension that have a partial or complete response to external beam. On the basis of these results, a 95% consensus volume was generated for CT and for MR. Online contouring atlases are available for instruction at http://www.nrgoncology.org/Resources/ContouringAtlases/GYNCervicalBrachytherapy.aspx.