Carboplatin in metastatic castration-resistant prostate cancer patients with molecular alterations of the DNA damage repair pathway: the PRO-CARBO phase II trial

Introduction

DNA damage repair genes are altered in 20-35% of metastatic castration-resistant prostate cancer (mCRPC). Poly-ADP (Adénosine Diphosphate)-ribose polymerase inhibitors (PARPi) showed significant activity for these selected tumors, especially with homologous recombination repair (HRR) deficiency. These alterations could also predict platinum sensitivity. Although carboplatin was inconclusive in unselected mCRPC, the literature suggests an anti-tumoral activity in mCRPC with HHR gene alterations. We aimed to assess the efficacy of carboplatin monotherapy in mCRPC patients with HRR deficiency.

Methods

This prospective multicenter single-arm two-stage phase II addressed mCRPC men with HRR somatic and/or germline alterations, pretreated with ⩾2 taxane chemotherapy regimens and one androgen receptor pathway inhibitor. Prior PARPi treatment was allowed. Enrolled patients received intravenous carboplatin (AUC5) every 21 days for 6-9 cycles. The primary endpoint was the best response rate according to adapted PCWG3 guidelines: radiological response (RECIST 1.1 criteria) and/or biological response [⩾50% prostate-specific antigen (PSA) decline].

Results

A total of 15 out of 16 enrolled patients started carboplatin treatment. Genomic alterations were identified for BRCA2 (n = 5), CDK12 (n = 3), ATM (n = 3) CHEK2 (n = 2), CHEK1 (n = 1), and BRCA1 (n = 1) genes. Objective response (partial biological response + stable radiological response) was achieved in one patient (6.7%), carrying a BRCA2 mutation and not pre-treated with PARPi; stable disease was observed for five patients (33.5%). Among seven patients (46.7%) with previous PARPi treatment, four patients (57.1%) had a stable disease. The median progression-free and overall survivals were 1.9 [95% confidence interval (95% CI), 1.8-9.5] and 8.6 months (95% CI, 4.3-19.5), respectively. The most common severe (grade 3-4) treatment-related toxicities were thrombocytopenia (66.7%), anemia (66.7%), and nausea (60%). Overall, 8 (53.3%) patients experienced a severe hematological event.

Conclusion

The study was prematurely stopped as pre-planned considering the limited activity of carboplatin monotherapy in heavily pre-treated, HHR-deficient mCRPC patients. Larger experience is needed in mCRPC with BRCA alterations.

Trial registration

NCT03652493, EudraCT ID number 2017-004764-35.

Pembrolizumab in patients with rare and ultra-rare sarcomas (AcSé Pembrolizumab): analysis of a subgroup from a non-randomised, open-label, phase 2, basket trial

BACKGROUND

Sarcoma is a heterogeneous group of diseases with few treatment options. Immunotherapy has shown little activity in studies including unselected sarcomas, but immune checkpoint blockers have shown activity in specific histotypes. We evaluated the activity of pembrolizumab in rare and ultra-rare sarcomas.

METHODS

AcSé Pembrolizumab is an ongoing phase 2, basket, multitumour study investigating the activity of pembrolizumab monotherapy in rare cancers. Here, we report the results obtained in patients with selected histotypes of rare sarcomas (incidence of less than one case per 1 000 000 people per year) recruited at 24 French hospitals. Key inclusion criteria were age 15 years or older, Eastern Cooperative Oncology Group performance status of 0-1, and advanced disease that was untreated and resistant to treatment. Patients were given pembrolizumab 200 mg intravenously on day 1 of every 21-day cycle for a maximum of 24 months. The primary endpoint was objective response rate at week 12 using Response Evaluation Criteria in Solid Tumours version 1.1, assessed by local investigators. The primary endpoint and safety were analysed in the intention-to-treat population. The AcSé Pembrolizumab study is registered with ClinicalTrials.gov, NCT03012620.

FINDINGS

Between Sept 4, 2017, and Dec 29, 2020, 98 patients were enrolled, of whom 97 received treatment and were included in analyses (median age 51 years [IQR 35-65]; 53 [55%] were male; 44 [45%] were female; no data were collected on race or ethnicity). 34 (35%) patients had chordomas, 14 (14%) had alveolar soft part sarcomas, 12 (12%) had SMARCA4-deficient sarcomas or malignant rhabdoid tumours, eight (8%) had desmoplastic small round cell tumours, six (6%) had epithelioid sarcomas, four (4%) had dendritic cell sarcomas, three (3%) each had clear cell sarcomas, solitary fibrous tumours, and myxoid liposarcomas, and ten (10%) had other ultra-rare histotypes. As of data cutoff (April 11, 2022), median follow-up was 13·1 months (range 0·1-52·8; IQR 4·3-19·7). At week 12, objective response rate was 6·2% (95% CI 2·3-13·0), with no complete responses and six partial responses in the 97 patients. The most common grade 3-4 adverse events were anaemia (eight [8%] of 97), alanine aminotransferase and aspartate aminotransferase increase (six [6%]), and dyspnoea (five [5%]). 86 serious adverse events were reported in 37 patients. Five deaths due to adverse events were reported, none of which were determined to be related to treatment (two due to disease progression, two due to cancer, and one due to unknown cause).

INTERPRETATION

Our data show the activity and manageable toxicity of pembrolizumab in some rare and ultra-rare sarcoma histotypes, and support the PD-1/PD-L1 pathway as a potential therapeutic target in selected histotypes. The completion of the basket study will provide further evidence regarding the activity and toxicity of pembrolizumab in identified rare types of cancer.

FUNDING

The Ligue contre le cancer, INCa, MSD.

TRANSLATION

For the French translation of the abstract see Supplementary Materials section.

Platinum-induced nausea and vomiting in patients treated for head and neck cancer

INTRODUCTION

Swallowing difficulties in patients with advanced head and neck cancer (HNC) represent an obstacle to adequate antiemetic prophylaxis before chemotherapy. We aim to assess chemotherapy-induced nausea and vomiting (CINV) risk in HNC patients in our center, with a specific focus among patients who could not receive appropriate NK1 receptor antagonist (NK1-RA) prophylaxis.

MATERIALS AND METHODS

Prospective observational monocentric study. CINV were evaluated with the MASCC Antiemesis Tool self-questionnaire (MAT) for all patients treated by platinum-based chemotherapy for advanced HNC (January-April 2019), thereafter, only for patients without NK1-RA prophylaxis due to swallowing difficulties were included (May-October 2019).

RESULTS

Sixty-one patients were included (82% male, 49.2% reccurent/metastatic disease), 18 did not received NK1-RA prophylaxis due to swallowing difficulties. Among 52 patients included from January to April 2019, 17.3% reported swallowing difficulties. The chemotherapy regimen was highly and moderately emetic for 40 (65.6%) and 21 patients (34.4%), respectively. CINV was associated with both cisplatin-based chemotherapy (OR 10.66, 95% CI [2.17-52.08]) and exclusive chemotherapy (OR 7.76, 95% CI [1.79-33.78]). Patients who did not receive anti-NK1 prophylaxis had no more CINV than patients with adequate CINV prophylaxis.

DISCUSSION

CINV remains frequent in patients treated by platinum-based chemotherapy for HNC. Oral NK1-RA prophylaxis can be unavailable because of swallowing difficulties, without an increased risk of CINV.

Outcomes of patients with metastatic castration resistant prostate cancer according to somatic sequencing of domage DNA repair genes

e17595

Background: More than 20% of mCRPC present somatic DNA damage repair gene mutation (DDR). If some data are available for germline mutations, there are few studies describing the relation between somatic alterations and response to standard therapies in mCRPC. Methods: To describe outcomes of mCRPC patients treated with standard therapies according to somatic DDR status.A retrospective somatic analysis on a 69-gene panel was conducted among mCRPC patients. Progression-free survival (PFS) of first-line treatment was analyzed according to somatic DDR mutation as primary endpoint. First exposition to taxanes chemotherapy and PFS2 (time to the second event of disease progression) depending on therapeutic sequences (new-generation hormonotherapy [NGHT]/taxanes chemotherapy) were also analyzed. Results: Among 83 patients tested, 33 (40%) had a somatic DDR mutation, including 10 ATM, 5 BRCA2, 4 CHEK2, 3 CDK12, 3 FANCG, 1 BLM, 1 CHEK1, 1 FANCF, 1 FANCI, 1 FANCM, 1 MDC1, 1 MRE11A and 1 PALB2. In first-line treatment, 20 patients received taxanes and 63 NGHT. Median PFS was 9.8 months for mutated patients and 8.4 months for non-mutated patients (p = 0.9). For mutated patients, median PFS was 12.3 months in taxanes group and 9.8 months in NGHT group, (p = 0.74). One BRCA2-mutated patient treated by docetaxel was particularly long responder (PFS = 39.2 months). PFS of first exposition to taxanes was 8.2 months among mutated patients and 5.7 months among non-mutated patients (p = 0.31). Patients with BRCA1/BRCA2/ATM mutations had longer PFS compared to the others patients (10.6 months versus 5.5 months, p = 0.04). Ten patients received the chemotherapy-NGHT sequence (CHS) and 28 the NGHT-chemotherapy sequence (HCS). PFS2 were 16.5 months for mutated patients, whatever the sequence, and 11.7 months among non-mutated patients (p = 0.07). The 3 mutated patients (1 BRCA1, 1 BRCA2, 1 ATM mutation) had long PFS2 in the CHS (49.8 months). PFS2 of mutated patients in HCS was 15.6 months. Conclusions: Mutated mCRPC patients benefit from standard therapies, with long responders to taxanes among patients with BRCA1/2 and ATM mutations.

How and when to refer patients for oncogenetic counseling in the era of PARP inhibitors

Poly(ADP-ribose)polymerase (PARP) inhibitors are targeted therapy for cancers with homologous repair deficiency (HRD). They were first approved for ovarian cancer and have changed current treatment strategies. They have also demonstrated efficacy in HER2-negative metastatic breast cancer and advanced prostate cancer with BRCA1/2 or ATM mutations. Patients with somatic and/or germline BRCA1/2 mutations benefit more from these treatments than other patients. Nowadays, the diagnosis of HRD is largely based on germline genetic testing, which is performed after an in-person genetic counseling session, even for patients without any family history of cancer. However, with the increasing number of PARP inhibitor indications across different tumor types, rapid access to oncogenetic consultations will become a challenge. To meet this demand, tumor genomic testing could be offered at initial diagnosis. Telephone counseling and other referral systems could replace in-person consultations for certain subgroups of patients deemed to have a low risk of harboring a germline mutation. This article reviews international guidelines for genetic counseling testing. We herein propose new care pathways for breast, prostate and ovarian cancers, including tumor genomic testing at initial diagnosis in order to help triage genetic counseling referrals.

[Malignant mesothelioma and constitutional BAP1 gene mutations]

Malignant mesothelioma is a rare tumour, usually the result of asbestos exposure. Several cases of familial aggregation have been reported and recently shown to be associated with constitutional mutations of the BAP1 gene. BAP1 is a deubiquitinating enzyme implicated in several different cellular mechanisms such as the repair or differentiation of DNA. About a half of malignant mesotheliomas present a somatic, bi-allelic inactivation of BAP1, demonstrated by nuclear extinction on histochemistry. Constitutional alterations of BAP1 are extremely rare. Present in the heterozygous state they are transmitted as an autosomal dominant. They are associated with a risk of developing other tumours such as uveal and cutaneous melanomas, benign melanocytic tumours (melanocytic BAP1-mutated atypical intradermal tumour or MBAITS) and clear cell renal carcinomas. The causal link between mesothelioma and germinal mutations of BAP1 has still not been clearly identified. At present there is, in France, no consensus on recommendations for the management of patients with these mutations. This article is a synthesis of the literature on the functions of the BAP1 gene, the tumour risks related to its alteration and the follow up of patients bearing a constitutional mutation.