Activity of Lutetium-177 Prostate-specific Membrane Antigen and Determinants of Outcomes in Patients with Metastatic Castration-resistant Prostate Cancer Previously Treated with Cabazitaxel: The PACAP Study.

BACKGROUND: Both cabazitaxel and lutetium-177 prostate-specific membrane antigen (Lu-PSMA) improve survival in metastatic castration-resistant prostate cancer (mCRPC) after an androgen receptor pathway inhibitor and docetaxel, but there are limited data regarding Lu-PSMA activity after cabazitaxel. OBJECTIVE: To assess the activity of Lu-PSMA and determinants of outcomes after cabazitaxel in mCRPC. DESIGN, SETTING, AND PARTICIPANTS: A retrospective analysis was conducted of consecutive mCRPC patients from eight European centers treated with Lu-PSMA after cabazitaxel. INTERVENTION: Lu-PSMA every 6-8 wk at a dose of 6-7.6 GBq. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary endpoint was radiographic progression-free survival (rPFS). The secondary endpoints included time to prostate-specific antigen (PSA) progression (TTPSA), overall survival (OS), PSA decline, objective response rate (ORR), clinical benefit, and safety. RESULTS AND LIMITATIONS: Of 126 patients, 68% had International Society of Urological Pathology (ISUP) grade 4-5 disease, 21% had visceral metastases, and 7% had lymph node disease only. DNA damage repair (DDR) alterations were detected in 11/50 (22%) patients with available testing. Patients received a median number of 3 Lu-PSMA cycles (interquartile range 2-4). With a median follow-up of 12.0 mo, the median rPFS was 4.4 mo (95% confidence interval [CI] 3.2-5.4), TTPSA 3.5 mo (95% CI 3.0-4.6), and OS 8.9 mo (95% CI 6.5-12.7). The ORR was 35%, and 55 patients (44%) experienced a PSA decline of ≥50%. The time to castration resistance of <12 mo was associated with shorter rPFS (p = 0.01). A similar trend was observed for ISUP grade 4-5 (p = 0.08), and baseline positron-emission tomography parameters including PSMA mean standardized uptake value (SUV) and maximum SUV (respectively, p = 0.06 and 0.05). The duration of previous cabazitaxel or DDR status did not impact outcomes. Patients experiencing a PSA decline of ≥ 50% on therapy demonstrated longer rPFS, TTPSA, and OS (all p < 0.0001). Limitations include retrospective data collection and investigator-based rPFS assessment. CONCLUSIONS: Lu-PSMA demonstrated a substantial PSA decline but limited rPFS after cabazitaxel in a real-life setting. Adverse baseline characteristics, baseline positron-emission tomography parameters, and quality of PSA response may help identify patients less likely to benefit from Lu-PSMA. PATIENT SUMMARY: Lutetium-177 prostate-specific membrane antigen (Lu-PSMA) improved outcomes in patients with castration-resistant prostate cancer, but there are limited data about its activity after cabazitaxel, a chemotherapy that is also the standard of care in this setting. We conducted a study across eight European centers and showed substantial responses on Lu-PSMA after cabazitaxel, although activity was short lived in a heavily pretreated population. Our findings prompt for real-life evaluation of Lu-PSMA in earlier settings to define the best therapeutic sequence.

Development of Novel Models of Aggressive Variants of Castration-resistant Prostate Cancer.

BACKGROUND: Genomic studies have identified new subsets of aggressive prostate cancer (PCa) with poor prognosis (eg, neuroendocrine prostate cancer [NEPC], PCa with DNA damage response [DDR] alterations, or PCa resistant to androgen receptor pathway inhibitors [ARPIs]). Development of novel therapies relies on the availability of relevant preclinical models. OBJECTIVE: To develop new preclinical models (patient-derived xenograft [PDX], PDX-derived organoid [PDXO], and patient-derived organoid [PDO]) representative of the most aggressive variants of PCa and to develop a new drug evaluation strategy. DESIGN, SETTING, AND PARTICIPANTS: NEPC (n = 5), DDR (n = 7), and microsatellite instability (MSI)-high (n = 1) PDXs were established from 51 patients with metastatic PCa; PDXOs (n = 16) and PDOs (n = 6) were developed to perform drug screening. Histopathology and treatment response were characterized. Molecular profiling was performed by whole-exome sequencing (WES; n = 13), RNA sequencing (RNA-seq; n = 13), and single-cell RNA-seq (n = 14). WES and RNA-seq data from patient tumors were compared with the models. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Relationships with outcome were analyzed using the multivariable chi-square test and the tumor growth inhibition test. RESULTS AND LIMITATIONS: Our PDXs captured both common and rare molecular phenotypes and their molecular drivers, including alterations of BRCA2, CDK12, MSI-high status, and NEPC. RNA-seq profiling demonstrated broad representation of PCa subtypes. Single-cell RNA-seq indicates that PDXs reproduce cellular and molecular intratumor heterogeneity. WES of matched patient tumors showed preservation of most genetic driver alterations. PDXOs and PDOs preserve drug sensitivity of the matched tissue and can be used to determine drug sensitivity. CONCLUSIONS: Our models reproduce the phenotypic and genomic features of both common and aggressive PCa variants and capture their molecular heterogeneity. Successfully developed aggressive-variant PCa preclinical models provide an important tool for predicting tumor response to anticancer therapy and studying resistance mechanisms. PATIENT SUMMARY: In this report, we looked at the outcomes of preclinical models from patients with metastatic prostate cancer enrolled in the MATCH-R trial (NCT02517892).

A Phase I Study of Acapatamab, a Half-life Extended, PSMA-Targeting Bispecific T-cell Engager for Metastatic Castration-Resistant Prostate Cancer.

PURPOSE: Safety and efficacy of acapatamab, a prostate-specific membrane antigen (PSMA) x CD3 bispecific T-cell engager were evaluated in a first-in-human study in metastatic castration-resistant prostate cancer (mCRPC). PATIENTS AND METHODS: Patients with mCRPC refractory to androgen receptor pathway inhibitor therapy and taxane-based chemotherapy received target acapatamab doses ranging from 0.003 to 0.9 mg in dose exploration (seven dose levels) and 0.3 mg (recommended phase II dose) in dose expansion intravenously every 2 weeks. Safety (primary objective), pharmacokinetics, and antitumor activity (secondary objectives) were assessed. RESULTS: In all, 133 patients (dose exploration, n = 77; dose expansion, n = 56) received acapatamab. Cytokine release syndrome (CRS) was the most common treatment-emergent adverse event seen in 97.4% and 98.2% of patients in dose exploration and dose expansion, respectively; grade ≥ 3 was seen in 23.4% and 16.1%, respectively. Most CRS events were seen in treatment cycle 1; incidence and severity decreased at/beyond cycle 2. In dose expansion, confirmed prostate-specific antigen (PSA) responses (PSA50) were seen in 30.4% of patients and radiographic partial responses in 7.4% (Response Evaluation Criteria in Solid Tumors 1.1). Median PSA progression-free survival (PFS) was 3.3 months [95% confidence interval (CI): 3.0-4.9], radiographic PFS per Prostate Cancer Clinical Trials Working Group 3 was 3.7 months (95% CI: 2.0-5.4). Acapatamab induced T-cell activation and increased cytokine production several-fold within 24 hours of initiation. Treatment-emergent antidrug antibodies were detected in 55% and impacted serum exposures in 36% of patients in dose expansion. CONCLUSIONS: Acapatamab was safe and tolerated and had a manageable CRS profile. Preliminary signs of efficacy with limited durable antitumor activity were observed. Acapatamab demonstrated pharmacokinetic and pharmacodynamic activity.

Targeted Inhibition of CYP11A1 in Castration-Resistant Prostate Cancer.

BACKGROUND: Prostate cancer is regulated by steroid hormones, even in castration-resistant disease. ODM-208, a novel inhibitor of cytochrome P450 11A1 (which catalyzes the first step of steroid-hormone biosynthesis), was investigated in patients with heavily pretreated metastatic castration-resistant prostate cancer (mCRPC). METHODS: CYPIDES is a first-in-human phase 1 (3 + 3 design) and phase 2 study. We administered ODM-208 twice daily with glucocorticoid/mineralocorticoid replacement and ongoing androgen deprivation therapy to adults with previously treated mCRPC, regardless of androgen receptor gene (AR) ligand-binding domain mutations (phase 1) and with activating AR ligand-binding domain mutations (ARmut; phase 2). Safety, pharmacokinetics, steroid-hormone pharmacodynamics, and preliminary efficacy were the key outcomes. RESULTS: Ninety-two patients received one or more doses of ODM-208: 47 in phase 1 (20 [42.6%] with ARmut) and 45 in phase 2 (all ARmut). A dose of ODM-208 of 5 mg twice a day with dexamethasone 1 mg/fludrocortisone 0.1 mg provided a balance between decreased steroidogenesis and toxicity. Treatment-related adrenal insufficiency was the most common toxicity in phase 1 (n=17, 36.2%; necessitating ODM-208 discontinuation in one patient); this toxicity occurred in six patients (13.3%) at 5 mg twice a day in phase 2. Median circulating testosterone levels declined from 3.0 ng/dl (interquartile range, 1.3 to 6.2 ng/dl) at baseline to undetectable levels within the first week of ODM-208 5 mg twice a day treatment in 46 of 53 (87%) patients. A decrease in prostate-specific antigen levels of 50% or more occurred in 14 of 19 (73.7%) patients with ARmut and 2 of 23 (8.7%) patients with AR wild type in phase 1 and in 24 of 45 (53.3%) patients with ARmut in phase 2. CONCLUSIONS: ODM-208 potently inhibited steroid-hormone biosynthesis with the expected toxicity of adrenal insufficiency. Evidence of antitumor activity was observed in this heavily pretreated mCRPC population, especially in those with ARmut. (Funded by Orion Pharma; ClinicalTrials.gov number, NCT03436485.)

Clinical utility of plasma ctDNA sequencing in metastatic urothelial cancer.

BACKGROUND: Genomic stratification may help improve the management of patients with metastatic urothelial cancer (mUC), given the recent identification of targetable alterations. However, the collection of tissue samples remains challenging. Here, we assessed the clinical utility of plasma circulating tumour DNA (ctDNA) sequencing in these patients. METHODS: Patients with mUC were prospectively enroled in the STING trial (NCT04932525), in which ctDNA was profiled using the Foundation One Liquid CDx Assay (324 genes, blood tumour mutational burden [bTMB], microsatellite instability status). Each genomic report was reviewed by a multidisciplinary tumor board (MTB). RESULTS: Between January 2021 and June 2022, 140 mUC patients underwent molecular profiling. The median time to obtain the assay results was 20 days ((confidence interval) CI95%: [20,21]). The ctDNA analysis reproduced the somatic genomic landscape of previous tissue-based cohorts. Concordance for serial ctDNA samples was strong (r = 0.843 CI95%: [0.631-0.938], p < 0.001). At least one actionable target was detected in 63 patients (45%) with a total of 35 actionable alterations, including bTMB high (≥10 mutations/Mb) (N = 39, 21.1%), FGFR3 (N = 20, 10.8%), and Homologous recombination deficiency (HRD) alterations (N = 14, 7.6%). MTB recommended matched therapy in 63 patients (45.0%). Eight patients (5.7%) were treated, with an overall response rate of 50% (CI95%: 15.70-84.30) and a median progression-free survival (PFS) of 5.2 months (CI95%: 4.1 - NR). FGFR3 alterations were associated with a shorter PFS in patients treated with immunotherapy. CONCLUSION: Overall, we demonstrated that genomic profiling with ctDNAs in mUC is a reliable and feasible approach for the timely initiation of genotype-matched therapies.

Efficacy and safety of cabozantinib rechallenge in metastatic renal cell carcinoma: A retrospective multicentric study.

BACKGROUND: Despite metastatic renal cell carcinoma (mRCC) expanded treatment options, disease progression ultimately occurs for most patients. Rechallenge may be a compelling strategy in a refractory setting. Cabozantinib is the standard of care in first and later lines of therapy, but its activity in rechallenge is unknown. METHODS: This retrospective study assessed the efficacy and safety of cabozantinib rechallenge, as defined by a second exposure after an interval of ≥3 months without treatment or ≥1 other treatment line, in patients with mRCC. The primary endpoint was median progression-free survival (PFS) at rechallenge. Secondary endpoints included overall survival, objective response rate, and safety at rechallenge. RESULTS: We included 51 mRCC patients who received cabozantinib in a rechallenge setting between 2017 and 2022. Median age at diagnosis was 54 years, 78% were male, 90% had clear cell mRCC, and 92% had prior nephrectomy. 15 patients (29%) were rechallenged after a pause in treatment, whereas 36 (70.6%) had ≥1 other treatment lines between first cabozantinib exposure (CABO-1) and rechallenge (CABO-2). Median PFS was 15.1 months (mo, 95% Confidence interval 11.2-22.1) at CABO-1 and 14.4mo (95%CI 9.8-NR) at CABO-2. Median overall survival was 67.6mo for CABO-1 (95% CI 52.2-NR) and 27.4mo for CABO-2 (95%CI 17.2-NR); objective response rate was 70.6% for CABO-1 and 60% for CABO-2. CABO-2 PFS was higher for patients with CABO-1 PFS > 12 months, and for those who discontinued CABO-1 because of toxicity, without statistical significance. There were no unexpected adverse events. CONCLUSIONS: Cabozantinib rechallenge is a feasible treatment option with potential clinical benefit for mRCC patients.

Genomic Profiling of Metastatic Castration-Resistant Prostate Cancer Samples Resistant to Androgen Receptor Pathway Inhibitors.

PURPOSE: The androgen receptor axis inhibitors (ARPI; e.g., enzalutamide, abiraterone acetate) are administered in daily practice for men with metastatic castration-resistant prostate cancer (mCRPC). However, not all patients respond, and mechanisms of both primary and acquired resistance remain largely unknown. EXPERIMENTAL DESIGN: In the prospective trial MATCH-R (NCT02517892), 59 patients with mCRPC underwent whole-exome sequencing (WES) and/or RNA sequencing (RNA-seq) of samples collected before starting ARPI. Also, 18 patients with mCRPC underwent biopsy at time of resistance. The objectives were to identify genomic alterations associated with resistance to ARPIs as well as to describe clonal evolution. Associations of genomic and transcriptomic alterations with primary resistance were determined using Wilcoxon and Fisher exact tests. RESULTS: WES analysis indicated that no single-gene genomic alterations were strongly associated with primary resistance. RNA-seq analysis showed that androgen receptor (AR) gene alterations and expression levels were similar between responders and nonresponders. RNA-based pathway analysis found that patients with primary resistance had a higher Hedgehog pathway score, a lower AR pathway score and a lower NOTCH pathway score than patients with a response. Subclonal evolution and acquisition of new alterations in AR-related genes or neuroendocrine differentiation are associated with acquired resistance. ARPIs do not induce significant changes in the tumor transcriptome of most patients; however, programs associated with cell proliferation are enriched in resistant samples. CONCLUSIONS: Low AR activity, activation of stemness programs, and Hedgehog pathway were associated with primary ARPIs' resistance, whereas most acquired resistance was associated with subclonal evolution, AR-related events, and neuroendocrine differentiation. See related commentary by Slovin, p. 4323.

Stage II Seminoma: Why Chemotherapy Should Remain a Standard.

Chemotherapy (three cycles of bleomycin + etoposide + cisplatin or four of etoposide + cisplatin) cures the vast majority of stage II seminomas. Retroperitoneal lymph node dissection (RPLND) is safe in early-stage seminoma, but the risk of relapse is not negligible. Long-term chemotherapy side effects are a reality but may be reduced using de-escalation strategies such as in the SEMITEP trial design, motivated by growing interest in survivorship. RPLND may be an option for well-informed select patients who understand that it may be associated with a higher rate of relapse than with cisplatin-based chemotherapy. In any case, local and systemic treatment should not be performed outside high-volume centers.

Emerging and Evolving Concepts in Cancer Immunotherapy Imaging.

Criteria based on measurements of lesion diameter at CT have guided treatment with historical therapies due to the strong association between tumor size and survival. Clinical experience with immune checkpoint modulators shows that editing immune system function can be effective in various solid tumors. Equally, novel immune-related phenomena accompany this novel therapeutic paradigm. These effects of immunotherapy challenge the association of tumor size with response or progression and include risks and adverse events that present new demands for imaging to guide treatment decisions. Emerging and evolving approaches to immunotherapy highlight further key issues for imaging evaluation, such as dissociated response following local administration of immune checkpoint modulators, pseudoprogression due to immune infiltration in the tumor environment, and premature death due to hyperprogression. Research that may offer tools for radiologists to meet these challenges is reviewed. Different modalities are discussed, including immuno-PET, as well as new applications of CT, MRI, and fluorodeoxyglucose PET, such as radiomics and imaging of hematopoietic tissues or anthropometric characteristics. Multilevel integration of imaging and other biomarkers may improve clinical guidance for immunotherapies and provide theranostic opportunities.

The Role of CT in the Staging and Follow-Up of Testicular Tumors: Baseline, Recurrence and Pitfalls.

Ultrasound imaging of the testis represents the standard-of-care initial imaging for the diagnosis of TGCT, whereas computed tomography (CT) plays an integral role in the initial accurate disease staging (organ-confined, regional lymph nodes, or sites of distant metastases), in monitoring the response to therapy in patients who initially present with non-confined disease, in planning surgical approaches for residual masses, in conducting follow-up surveillance and in determining the extent of recurrence in patients who relapse after treatment completion. CT imaging has also an important place in diagnosing complications of treatments. The aims of this article are to review these different roles of CT in primary TGCT and focus on different pitfalls that radiologists need to be aware of.

PALLIA 10 score in phase I cancer studies.

OBJECTIVE: Phase I clinical trials usually include patients with advanced disease who have failed standard therapies and should benefit from early palliative care. We try to assess whether PALLIA 10, a score developed in France to help identify patients who might benefit from a palliative care referral, could be used in a phase I department trial. METHODS: We assessed PALLIA 10 score and other prognostic factors in patients enrolled in phase I trials at Gustave Roussy Cancer Center prospectively during two periods of time (cohort 1 (C1) and 2 (C2)). A double-blind assessment of the PALLIA 10 score was done in C2 by a palliative care specialist and a nurse. RESULTS: From 1 July 2018 to 1 November 2018 (C1) and from 1 December 2020 to 16 April 2021 (C2), 86 patients were assessed in C1 and 302 in C2. Median PALLIA 10 was very low in both cohorts (median 1, range 1-5 in C1 and 1-8 in C2). On C1 and C2, 12% and 5% of patients had a dedicated palliative consultation. In C2, assessment of PALLIA 10 score was significantly different between palliative care physician (median 5, range 3-8), phase I physician (median 1, range 1-6) and phase I nurse (median 3, range 1-8) (p<0.001). CONCLUSION: Median PALLIA 10 score was low when assessed by the phase I physician, which suggests the need for a better tool and appropriate clinician's education to implement early palliative care in clinical practice and trials.

FOLFIRI plus BEvacizumab or aFLIbercept after FOLFOX-bevacizumab failure for COlorectal cancer (BEFLICO): An AGEO multicenter study.

After failure of first line FOLFOX-bevacizumab for metastatic colorectal cancer (mCRC), adding either bevacizumab or aflibercept to second-line FOLFIRI increases survival compared to FOLFIRI alone. In this French retrospective multicentre cohort, we included patients with a mCRC treated with either FOLFIRI-aflibercept or FOLFIRI-bevacizumab. The primary endpoint was overall survival (OS), and secondary endpoints were progression-free survival (PFS), disease control rate (DCR: CR + PR + SD) and safety. We included 681 patients from 36 centers, 326 and 355 in the aflibercept and bevacizumab groups, respectively. Median age was 64.2 years and 45.2% of patients were men. Most patients had RAS-mutated tumors (80.8%) and synchronous metastases (85.7%). After a median follow up of 31.2 months, median OS was 13.0 months (95% CI: 11.3-14.7) and 10.4 months (95% CI: 8.8-11.4) in the bevacizumab and aflibercept groups, respectively (P < .0001). Median PFS was 6.0 months (95% CI: 5.4-6.5) and 5.1 months (95% CI: 4.3-5.6) (P < .0001). After adjustment on age, PS, PFS of first line, primary tumor resection, metastasis location and RAS/BRAF status, bevacizumab was still associated with better OS (HR: 0.71, 95% CI: 0.59-0.86, P = .0003). FOLFIRI-bevacizumab combination was associated with longer OS and PFS, and a better tolerability, as compared to FOLFIRI-aflibercept after progression on FOLFOX-bevacizumab.

PARP Inhibition, a New Therapeutic Avenue in Patients with Prostate Cancer.

Up to 25% of patients with metastatic prostate cancer present with germline or somatic DNA damage repair alterations, some of which are associated with aggressive disease and poor outcomes. New data have brought poly(ADP-ribose) polymerase (PARP) inhibitors into sharp focus in the treatment of metastatic castrate-resistant prostate cancer (mCRPC). Olaparib improved survival after at least one new hormonal therapy (NHT) in a cohort of patients harboring BRCA1, BRCA2 or ATM mutations in the PROfound trial, while rucaparib, talazoparib and niraparib demonstrated compelling activity in phase II trials. While patients with prostate cancer and BRCA1 or BRCA2 mutations may derive greatest benefit of PARP inhibition, the magnitude of benefit seems much lower in the context of most other homologous recombination gene mutations. Several PARP inhibitors are currently developed in combination with conventional therapy, including chemotherapy, NHT, and alpha-particle emitters, at different disease stages. Herein, we review the rationale for PARP inhibition in patients with prostate cancer, discuss the impact of PARP inhibitors on outcomes, and explore underlying challenges for future developments.

Radiological patterns of tumour progression in patients treated with a combination of immune checkpoint blockers and antiangiogenic drugs.

BACKGROUND: Immune checkpoint blockers (ICBs) in combination with antiangiogenic drugs showed synergistic efficacy in several tumour types. New patterns of progression have recently been defined upon treatment with ICB alone including atypical responses such as pseudoprogression (PsPD), dissociated response and hyperprogressive disease (HPD). This study aimed to describe the patterns of response observed in patients treated with combination ICB with antiangiogenic drugs. METHODS: We conducted a monocentric retrospective analysis of patients (pts) enrolled in phase I trials at Gustave Roussy assessing the combination of ICB and antiangiogenic drugs. Radiological CT scans were centrally reviewed by a senior radiologist according to iRECIST criteria including progressive disease (PD), partial response (PR) and stable disease (SD). HPD was defined as a progression at the first evaluation with a delta tumour growth rate exceeding 50%. PsPD was defined as initial progression followed by stabilisation or decrease of tumour size, DisR as a concomitant size decrease in some tumour lesions and size increase in others. Both PsPD and DisR are defined as atypical responses. Overall response rate included PR and complete response (CR) and disease control rate included PR, CR and SD. RESULTS: Between December 2016 and June 2020, 111 pts were included. The median follow up was 12.8 months (11.3-15.1). The most common tumour types were lung and pleura (20%), kidney (18%) and bladder (17%). The overall response rate and disease control rate were 21.6% (n = 24) and 59% (n = 65), respectively. Twenty-one patients (19%) experienced PD as the best response. PsPD, DisR and HPD were observed in 4 (3.6%), 11 (9.9%) and 7 (6.3%) pts, respectively. DisR and PsPD were associated with longer iProgression Free Survival (median: 6.9 and 18.9 months, respectively) and iOverall Survival (median: 28.4 and 31.1 months, respectively) than a median of SD in immune progression-free survival (median: 4.2 months) and immune overall survival (median: 12.7 months). CONCLUSION: Patients treated with ICBs and antiangiogenic agents display atypical responses. Survival might be longer in patients with DisR responses and PsPD disease than patients with HPD, PD and SD.

The Polarity and Specificity of Antiviral T Lymphocyte Responses Determine Susceptibility to SARS-CoV-2 Infection in Patients with Cancer and Healthy Individuals.

Vaccination against coronavirus disease 2019 (COVID-19) relies on the in-depth understanding of protective immune responses to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). We characterized the polarity and specificity of memory T cells directed against SARS-CoV-2 viral lysates and peptides to determine correlates with spontaneous, virus-elicited, or vaccine-induced protection against COVID-19 in disease-free and cancer-bearing individuals. A disbalance between type 1 and 2 cytokine release was associated with high susceptibility to COVID-19. Individuals susceptible to infection exhibited a specific deficit in the T helper 1/T cytotoxic 1 (Th1/Tc1) peptide repertoire affecting the receptor binding domain of the spike protein (S1-RBD), a hotspot of viral mutations. Current vaccines triggered Th1/Tc1 responses in only a fraction of all subject categories, more effectively against the original sequence of S1-RBD than that from viral variants. We speculate that the next generation of vaccines should elicit Th1/Tc1 T-cell responses against the S1-RBD domain of emerging viral variants. SIGNIFICANCE: This study prospectively analyzed virus-specific T-cell correlates of protection against COVID-19 in healthy and cancer-bearing individuals. A disbalance between Th1/Th2 recall responses conferred susceptibility to COVID-19 in both populations, coinciding with selective defects in Th1 recognition of the receptor binding domain of spike. See related commentary by McGary and Vardhana, p. 892. This article is highlighted in the In This Issue feature, p. 873.

Circulating tumor DNA as a dynamic biomarker of response to palbociclib and fulvestrant in metastatic breast cancer patients.

BACKGROUND: Following the PALOMA-3 study results, the combination of palbociclib, a CDK4/6 inhibitor, with fulvestrant, a selective estrogen receptor degrader, has become a standard therapy in women with estrogen receptor-positive (ER+) HER2-negative (HER2-) metastatic breast cancer (MBC). Palbociclib has been shown to increase the progression-free survival (PFS) overall but no predictive biomarker of palbociclib efficacy has been validated so far. We thus evaluated whether early changes of circulating tumor DNA (ctDNA) levels are associated with palbociclib plus fulvestrant efficiency. METHODS: ER+ HER2- MBC patients were included in a prospective observational cohort before treatment initiation. Tumor response was assessed by radiological evaluation (RECIST v1.1) every 3 months. Plasma samples were collected before treatment (baseline), at day 15 (D15), at day 30 (D30), and at disease progression. We searched for somatic mutations from archived tumor tissues by targeted deep sequencing. For patients with somatic mutations identified, circulating tumor DNA (ctDNA) was tracked using digital droplet PCR. Ratios of ctDNA levels ([D15/baseline] and [D30/baseline]) were then correlated with prospectively registered patient characteristics and outcomes. RESULTS: Twenty-five of the 61 patients enrolled had a somatic mutation testable in plasma (NPIK3CA = 21, NTP53 = 2, NAKT1 = 2). At baseline, 84% of patients had detectable ctDNA levels but ctDNA levels had no prognostic impact on PFS (p = 0.10). Among those patients, ctDNA was still detected in 82% at D15 and 68% at D30. ctDNA clearance observed at day 30 was associated with longer PFS (HR = 7.2, 95% CI = 1.5-32.6, p = 0.004). On the contrary, a [D30/baseline] ctDNA ratio > 1 was associated with a shorter PFS (HR = 5.1, 95% CI = 1.4-18.3, p = 0.02) and all 5 patients with increased ctDNA levels at D30 showed disease progression after 3 months under palbociclib-fulvestrant. Finally, at the time of radiological tumor progression, ctDNA was detected in all patients tested. CONCLUSION: Our study demonstrates that the efficiency of palbociclib and fulvestrant can be monitored by serial analyses of ctDNA before radiological evaluation and that early ctDNA variation is a prognostic factor of PFS.

Epstein-Barr virus-associated smooth muscle tumor in a kidney transplant recipient: A case-report and review of the literature.

INTRODUCTION: Epstein-Barr virus (EBV) is a herpesvirus linked to pre-malignant lymphoproliferative diseases and up to nine distinct human tumors. The most frequent EBV-associated malignancies are lymphomas and nasopharyngeal carcinoma. By promoting smooth muscle proliferation, EBV can induce EBV-associated smooth muscle tumors (SMT) which remain a very rare oncological entity. This study reports one case report of SMT and aims to offer the largest review of literature on post-transplantation-SMT (PT-SMT) in kidney transplant recipients, with a focus on therapeutic management and evolution of graft function. METHODS: Case reports and case series of PT-SMT in kidney transplant recipients were collected from 1996 to 2019. RESULTS: A total of 59 PT-SMT were evaluated. The median time at diagnosis was 74.6 months after kidney transplantation. The most frequent localizations were liver and lung. EBV seroconversion was notified in all six patients with previously negative status. Preferred therapeutic option was surgery (65.9%), associated with a reduction in immunosuppression (77.2%), which includes switch to mTOR inhibitors (29.5%), and discontinuation of MMF (32%). In our review, 13% of patients experienced rejection, 8.7% lost their graft and went back on hemodialysis; 8.8% of patients died of PT-SMT. CONCLUSION: PT-SMT is a rare but serious condition in kidney transplant recipients. EBV seroconversion following transplantation appears as a risk factor in developing PT-SMT in solid-organ recipients. In the absence of guidelines, therapeutic management for PT-SMT is challenging and exposes the patient to high risk of graft loss.

Patterns of progression in patients treated for immuno-oncology antibodies combination.

BACKGROUND: New patterns of progression under immune-oncology (IO) antibodies (mAb) have been described such as pseudoprogression. Except for melanoma, variations between studies reveal difficulties to establish their prevalence. METHODS: This retrospective study enrolled patients participating in IO phase I trials at Gustave Roussy cancer center for solid tumors excluding melanoma. Radiological assessment according to iRECIST was correlated with prospectively registered patient characteristics and outcomes. Pseudoprogression (PsPD) was defined as RECIST-defined progression followed by stabilization or decrease at the next imaging, and dissociated response (DisR) as concomitant decrease in some tumor lesions and increase in others at a same timepoint. RESULTS: Among 360 patients included, 74% received IO mAb combination: 45% with another IO mAb, 20% with targeted therapy and 10% with radiotherapy. The overall response rate was 19.7%. PsPD were observed in 10 (2.8%) patients and DisR in 12 (3.3%) patients. Atypical responses (AR), including PsPD and DisR, were not associated with any patient's baseline characteristics. Compare with typical responder patients, patients experiencing AR presented a shorter iPFS (HR 0.34; p < 0.001) and OS (HR 0.27; p = 0.026). Among the 203 patients who progressed in 12 weeks, 80 (39.4%) patients were treated beyond progression. PD was confirmed in 80% of cases, while 10% of patients presented a response. CONCLUSION: Pseudoprogression and dissociated response are uncommon patterns of progression. Their prevalence should be balanced with the rate of real progressing patients treated beyond progression. Prognosis or on-treatment biomarkers are needed to identify early patients who will benefit from immunotherapy.

Clinical Validity of HPV Circulating Tumor DNA in Advanced Anal Carcinoma: An Ancillary Study to the Epitopes-HPV02 Trial.

PURPOSE: Human papillomavirus (HPV) is found in 90% of squamous cell carcinomas of the anal canal (SCCA). We investigated the clinical validity of HPV circulating tumor DNA (ctDNA) detection in patients enrolled in the Epitopes-HPV02 trial that demonstrated the efficacy of docetaxel, cisplatin, and 5-FU as first-line chemotherapy in advanced SCCA. EXPERIMENTAL DESIGN: According to the protocol, serum samples were collected before chemotherapy and on completion of chemotherapy. HPV16 ctDNA was quantified by droplet digital PCR (ddPCR) and correlated with prospectively registered patient characteristics and outcomes. A landmark was set at the time of chemotherapy completion for postchemotherapy progression-free survival (PFS) analyses. RESULTS: Among 57 patients with HPV16-related advanced SCCA, HPV ctDNA was detected in 91.1% (95% confidence interval, 81.1-96.2) of baseline samples. Baseline HPV ctDNA levels were not associated with any patient characteristics; baseline ctDNA level below the cutoff obtained by AUC (area under the curve) was associated with a longer PFS (HR = 2.1; P = 0.04). Among the 36 patients who completed 5 months of chemotherapy, residual HPV ctDNA was detected after chemotherapy in 38.9% of patients. Residual HPV ctDNA detected at chemotherapy completion was associated with shorter postchemotherapy PFS (median PFS 3.4 months vs. not reached; HR = 5.5; P < 0.001) and a reduction of 1-year overall survival rate (OR = 7.0; P = 0.02). CONCLUSIONS: This prospective study in advanced SCCA demonstrated a significant prognostic impact of HPV ctDNA level before first-line chemotherapy and HPV ctDNA negativity after chemotherapy completion. With a limited cost and short turnaround, this assay is a promising tool to optimize the therapeutic management of SCCA.See related commentary by Morris, p. 2030.