ATARI trial: ATR inhibitor in combination with olaparib in gynecological cancers with ARID1A loss or no loss (ENGOT/GYN1/NCRI).

BACKGROUND: ARID1A (AT-rich interactive domain containing protein 1A) loss-of-function mutations have been reported in gynecological cancers, including rarer subtypes such as clear cell carcinoma. Preclinical studies indicate that ARID1A mutant cancers display sensitivity to ATR inhibition while tumors without ARID1A mutations may be sensitive to Ataxia telangiectasia and Rad3 related (ATR) inhibitors in combination with poly-ADP ribose polymerase (PARP) inhibitors. PRIMARY OBJECTIVE: To determine whether the ATR inhibitor, ceralasertib, has clinical activity as a single agent and in combination with the PARP inhibitor, olaparib, in patients with ARID1A 'loss' and 'no loss' clear cell carcinomas and other relapsed gynecological cancers. STUDY HYPOTHESIS: ARID1A deficient clear cell carcinoma of the ovary or endometrium is sensitive to ATR inhibition, while the combination of ATR and PARP inhibition has activity in other gynecological tumors, irrespective of ARID1A status. TRIAL DESIGN: ATARI (ENGOT/GYN1/NCRI) is a multicenter, international, proof-of-concept, phase II, parallel cohort trial assessing ceralasertib activity as a single agent and in combination with olaparib in ARID1A stratified gynecological cancers. Patients with relapsed ovarian/endometrial clear cell carcinoma with ARID1A loss will receive ceralasertib monotherapy (cohort 1A). Relapsed ovarian/endometrial clear cell carcinoma patients with no ARID1A loss (cohort 2) or patients with other histological subtypes (endometrioid, carcinosarcoma, cervical) (cohort 3) will receive combination therapy (olaparib/ceralasertib). Treatment will continue until disease progression. MAJOR INCLUSION/EXCLUSION CRITERIA: Patients with histologically confirmed recurrent clear cell (ovarian, endometrial, or endometriosis related), endometrioid (ovarian, endometrial, or endometriosis related), cervical (adenocarcinomas or squamous), or carcinosarcomas (ovarian or endometrial) are eligible. Patients progressing after ≥1 prior platinum with evidence of measurable (RECIST v1.1) radiological disease progression since last systemic anticancer therapy and prior to trial entry are eligible. Previous ATR or PARP inhibitor treatment is not permissible. PRIMARY ENDPOINT: Best overall objective response rate (RECIST v1.1). SAMPLE SIZE: A minimum of 40 and a maximum of 116. ESTIMATED DATES FOR COMPLETING ACCRUAL AND PRESENTING RESULTS: Accrual is anticipated to be complete by the second quarter of 2022, with reporting of results by the fourth quarter of 2022. Overall accrual targets and reporting timelines are dependent on individual cohort progression to stage 2. TRIAL REGISTRATION NUMBER: NCT0405269.

Homologous recombination DNA repair deficiency and PARP inhibition activity in primary triple negative breast cancer.

Triple negative breast cancer (TNBC) encompasses molecularly different subgroups, with a subgroup harboring evidence of defective homologous recombination (HR) DNA repair. Here, within a phase 2 window clinical trial, RIO trial (EudraCT 2014-003319-12), we investigate the activity of PARP inhibitors in 43 patients with untreated TNBC. The primary end point, decreased Ki67, occured in 12% of TNBC. In secondary end point analyses, HR deficiency was identified in 69% of TNBC with the mutational-signature-based HRDetect assay. Cancers with HRDetect mutational signatures of HR deficiency had a functional defect in HR, assessed by impaired RAD51 foci formation on end of treatment biopsy. Following rucaparib treatment there was no association of Ki67 change with HR deficiency. In contrast, early circulating tumor DNA dynamics identified activity of rucaparib, with end of treatment ctDNA levels suppressed by rucaparib in mutation-signature HR-deficient cancers. In ad hoc analysis, rucaparib induced expression of interferon response genes in HR-deficient cancers. The majority of TNBCs have a defect in DNA repair, identifiable by mutational signature analysis, that may be targetable with PARP inhibitors.

Cediranib in patients with alveolar soft-part sarcoma (CASPS): a double-blind, placebo-controlled, randomised, phase 2 trial.

BACKGROUND: Alveolar soft-part sarcoma (ASPS) is a rare soft-tissue sarcoma that is unresponsive to chemotherapy. Cediranib, a tyrosine-kinase inhibitor, has shown substantial activity in ASPS in non-randomised studies. The Cediranib in Alveolar Soft Part Sarcoma (CASPS) study was designed to discriminate the effect of cediranib from the intrinsically indolent nature of ASPS. METHODS: In this double-blind, placebo-controlled, randomised, phase 2 trial, we recruited participants from 12 hospitals in the UK (n=7), Spain (n=3), and Australia (n=2). Patients were eligible if they were aged 16 years or older; metastatic ASPS that had progressed in the previous 6 months; had an ECOG performance status of 0-1; life expectancy of more than 12 weeks; and adequate bone marrow, hepatic, and renal function. Participants had to have no anti-cancer treatment within 4 weeks before trial entry, with exception of palliative radiotherapy. Participants were randomly assigned (2:1), with allocation by use of computer-generated random permuted blocks of six, to either cediranib (30 mg orally, once daily) or matching placebo tablets for 24 weeks. Treatment was supplied in number-coded bottles, masking participants and clinicians to assignment. Participants were unblinded at week 24 or sooner if they had progression defined by Response Evaluation Criteria in Solid Tumors (version 1.1); those on placebo crossed over to cediranib and all participants continued on treatment until progression or death. The primary endpoint was percentage change in sum of target marker lesion diameters between baseline and week 24 or progression if sooner, assessed in the evaluable population (all randomly assigned participants who had a scan at week 24 [or sooner if they progressed] with target marker lesions measured). Safety was assessed in all participants who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, number NCT01337401; the European Clinical Trials database, number EudraCT2010-021163-33; and the ISRCTN registry, number ISRCTN63733470 recruitment is complete and follow-up is ongoing. FINDINGS: Between July 15, 2011, and July 29, 2016, of 48 participants recruited, all were randomly assigned to cediranib (n=32) or placebo (n=16). 23 (48%) were female and the median age was 31 years (IQR 27-45). Median follow-up was 34·3 months (IQR 23·7-55·6) at the time of data cutoff for these analyses (April 11, 2018). Four participants in the cediranib group were not evaluable for the primary endpoint (one did not start treatment, and three did not have their scan at 24 weeks). Median percentage change in sum of target marker lesion diameters for the evaluable population was -8·3% (IQR -26·5 to 5·9) with cediranib versus 13·4% (IQR 1·1 to 21·3) with placebo (one-sided p=0·0010). The most common grade 3 adverse events on (blinded) cediranib were hypertension (six [19%] of 31) and diarrhoea (two [6%]). 15 serious adverse reactions in 12 patients were reported; 12 of these reactions occurred on open-label cediranib, and the most common symptoms were dehydration (n=2), vomiting (n=2), and proteinuria (n=2). One probable treatment-related death (intracranial haemorrhage) occurred 41 days after starting open-label cediranib in a patient who was assigned to placebo in the masked phase. INTERPRETATION: Given the high incidence of metastatic disease and poor long-term prognosis of ASPS, together with the lack of efficacy of conventional chemotherapy, our finding of significant clinical activity with cediranib in this disease is an important step towards the goal of long-term disease control for these young patients. Future clinical trials in ASPS are also likely to involve immune checkpoint inhibitors. FUNDING: Cancer Research UK and AstraZeneca.

Conducting non-commercial international clinical trials: the ICR-CTSU experience.

BACKGROUND: Academic clinical trials play a fundamental role in the development of new treatments, the repurposing of existing treatments and in addressing areas of unmet clinical need. With cancer treatments increasingly targeted at molecular subtypes, and with priority placed on developing new treatments for rare tumour types, the need for international trial participation to access sufficient patient numbers for successful trial conduct is growing. However, lack of harmonisation of international legal, ethical and financial systems can make this challenging and the cost and effort of conducting trials internationally can be considered prohibitive, particularly where the sample size is comparatively small. METHODS: The Institute of Cancer Research - Clinical Trials and Statistics Unit (ICR-CTSU) is a UK-based academic clinical trials unit that specialises in the design, conduct and analysis of clinical trials of cancer treatments with an expanding portfolio of trials in molecular subtypes of breast and urological cancers and in other rare cancer types. Implementing appropriate mechanisms to enable international participation has therefore been imperative. In this article, we explain how we have approached the challenges involved and describe examples of successful international trial conduct, achieved through robust collaborations with academic and industry partners. CONCLUSION: Conducting academic trials internationally is challenging but can and should be achieved through appropriate governance mechanisms and strong collaborations.

Gpr83 expression is not required for the maintenance of intestinal immune homeostasis and regulation of T-cell-dependent colitis.

Regulatory T (T(R)) cells are integral to the maintenance of intestinal homeostasis, where an intricate balance between tolerance and immunity must be maintained. Recently, studies have focused on the identification of molecules involved in the function and/or development of T(R) cells. One such molecule, the G-protein coupled receptor Gpr83, has been identified through gene expression analysis as being overexpressed within thymic and peripheral naturally arising regulatory T (nT(R)) cell populations. The aim of this study was to further define the characteristics of Gpr83 expression and to investigate the role of Gpr83 in T(R)-cell development and function through the generation and analysis of Gpr83-deficient mice. Following activation, naïve CD4(+) T cells induce Gpr83 expression in a transforming growth factor (TGF)-beta dependent manner. Rather than being a general marker of activation, Gpr83 expression could only be detected in cells also expressing forkhead/winged helix transcription factor (Foxp3), further supporting the association of Gpr83 with the regulatory cell phenotype. Mice deficient in Gpr83 expression developed normally and did not display signs of inflammatory disease. Thymic nT(R)-cell development was unaffected by a lack of Gpr83 expression and peripheral nT(R)-cell homeostasis was normal when compared with that of wild-type mice. Gpr83 expression was dispensable for the regulatory activity of nT(R) cells as Gpr83-deficient nT(R) cells could suppress the development of disease in a T-cell transfer model of colitis. These results suggest a redundant role for Gpr83 in the function of T(R) cells in this model of disease. Further studies are required to determine the role of Gpr83 in T(R)-cell biology.