Genomic alterations in DNA damage repair (DDR) genes other than
may confer synthetic lethality with PARP inhibition in metastatic castration-resistant prostate cancer (mCRPC). To test this ...hypothesis, the phase II TRITON2 study of rucaparib included patients with mCRPC and deleterious non-
DDR gene alterations.
TRITON2 enrolled patients who had progressed on one or two lines of next-generation androgen receptor-directed therapy and one taxane-based chemotherapy for mCRPC. Key endpoints were investigator-assessed radiographic response per modified RECIST/PCWG3 and PSA response (≥50% decrease from baseline).
TRITON2 enrolled 78 patients with a non-
DDR gene alteration
(
= 49),
(
= 15),
(
= 12), and other DDR genes (
= 14). Among patients evaluable for each endpoint, radiographic and PSA responses were observed in a limited number of patients with an alteration in
2/19 (10.5%) and 2/49 (4.1%), respectively,
0/10 (0%) and 1/15 (6.7%), respectively, or
1/9 (11.1%) and 2/12 (16.7%), respectively, including no radiographic or PSA responses in 11 patients with confirmed biallelic
loss or 11 patients with
germline mutations. Responses were observed in patients with alterations in the DDR genes
, and
.
In this prospective, genomics-driven study of rucaparib in mCRPC, we found limited radiographic/PSA responses to PARP inhibition in men with alterations in
, or
. However, patients with alterations in other DDR-associated genes (e.g.,
) may benefit from PARP inhibition.
.
Poly (ADP-ribose) polymerase (PARP) inhibitors are approved for the treatment of breast cancer susceptibility genes 1 and 2 (BRCA1/2) mutant ovarian and breast cancers, and are now being evaluated in ...metastatic castration-resistant prostate cancer (mCRPC). Reversion mutations that restore BRCA1/2 function have been shown to be responsible for resistance to platinum-based chemotherapy and PARP inhibitors, however there is no information on the sequential use of these agents in prostate cancer.
A patient with mCRPC associated with a germline BRCA2 mutation was sequentially treated with carboplatin and the PARP inhibitor rucaparib. Genomic profiling of the available baseline tumor and progression blood samples using next-generation sequencing panel tests identified polyclonal BRCA2 reversion mutations post carboplatin treatment but prior to rucaparib treatment. A total of 12 somatic reversion mutations were detected and ranged from small indels to larger deletions of up to 387 amino acids. These alterations are all predicted to restore the BRCA2 open reading frame and potentially protein function. The patient received limited benefit while on rucaparib, likely due to these reversion mutations observed prior to treatment.
Here we report a case of a patient with prostate cancer who received a platinum agent and PARP inhibitor sequentially and in whom polyclonal BRCA2 reversion mutations were identified as the likely mechanism of acquired resistance to carboplatin and primary resistance to PARP inhibition. These findings suggest caution is warranted in sequencing these agents.
A widespread approach to modern cancer therapy is to identify a single oncogenic driver gene and target its mutant-protein product (for example, EGFR-inhibitor treatment in EGFR-mutant lung cancers). ...However, genetically driven resistance to targeted therapy limits patient survival. Through genomic analysis of 1,122 EGFR-mutant lung cancer cell-free DNA samples and whole-exome analysis of seven longitudinally collected tumor samples from a patient with EGFR-mutant lung cancer, we identified critical co-occurring oncogenic events present in most advanced-stage EGFR-mutant lung cancers. We defined new pathways limiting EGFR-inhibitor response, including WNT/β-catenin alterations and cell-cycle-gene (CDK4 and CDK6) mutations. Tumor genomic complexity increases with EGFR-inhibitor treatment, and co-occurring alterations in CTNNB1 and PIK3CA exhibit nonredundant functions that cooperatively promote tumor metastasis or limit EGFR-inhibitor response. This study calls for revisiting the prevailing single-gene driver-oncogene view and links clinical outcomes to co-occurring genetic alterations in patients with advanced-stage EGFR-mutant lung cancer.
Although targeted therapies often elicit profound initial patient responses, these effects are transient due to residual disease leading to acquired resistance. How tumors transition between drug ...responsiveness, tolerance and resistance, especially in the absence of preexisting subclones, remains unclear. In epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma cells, we demonstrate that residual disease and acquired resistance in response to EGFR inhibitors requires Aurora kinase A (AURKA) activity. Nongenetic resistance through the activation of AURKA by its coactivator TPX2 emerges in response to chronic EGFR inhibition where it mitigates drug-induced apoptosis. Aurora kinase inhibitors suppress this adaptive survival program, increasing the magnitude and duration of EGFR inhibitor response in preclinical models. Treatment-induced activation of AURKA is associated with resistance to EGFR inhibitors in vitro, in vivo and in most individuals with EGFR-mutant lung adenocarcinoma. These findings delineate a molecular path whereby drug resistance emerges from drug-tolerant cells and unveils a synthetic lethal strategy for enhancing responses to EGFR inhibitors by suppressing AURKA-driven residual disease and acquired resistance.
Purpose
Fibroblast activation protein (FAP) is a membrane-bound protease that has limited expression in normal adult tissues but is highly expressed in the tumor microenvironment of many solid ...cancers. FAP-2286 is a FAP-binding peptide coupled to a radionuclide chelator that is currently being investigated in patients as an imaging and therapeutic agent. The potency, selectivity, and efficacy of FAP-2286 were evaluated in preclinical studies.
Methods
FAP expression analysis was performed by immunohistochemistry and autoradiography on primary human cancer specimens. FAP-2286 was assessed in biochemical and cellular assays and in
in vivo
imaging and efficacy studies, and was further evaluated against FAPI-46, a small molecule–based FAP-targeting agent.
Results
Immunohistochemistry confirmed elevated levels of FAP expression in multiple tumor types including pancreatic, breast, and sarcoma, which correlated with FAP binding by FAP-2286 autoradiography. FAP-2286 and its metal complexes demonstrated high affinity to FAP recombinant protein and cell surface FAP expressed on fibroblasts. Biodistribution studies in mice showed rapid and persistent uptake of
68
Ga-FAP-2286,
111
In-FAP-2286, and
177
Lu-FAP-2286 in FAP-positive tumors, with renal clearance and minimal uptake in normal tissues.
177
Lu-FAP-2286 exhibited antitumor activity in FAP-expressing HEK293 tumors and sarcoma patient-derived xenografts, with no significant weight loss. In addition, FAP-2286 maintained longer tumor retention and suppression in comparison to FAPI-46.
Conclusion
In preclinical models, radiolabeled FAP-2286 demonstrated high tumor uptake and retention, as well as potent efficacy in FAP-positive tumors. These results support clinical development of
68
Ga-FAP-2286 for imaging and
177
Lu-FAP-2286 for therapeutic use in a broad spectrum of FAP-positive tumors.
or
(
) alterations are common in men with metastatic castration-resistant prostate cancer (mCRPC) and may confer sensitivity to poly(ADP-ribose) polymerase inhibitors. We present results from ...patients with mCRPC associated with a
alteration treated with rucaparib 600 mg twice daily in the phase II TRITON2 study.
We enrolled patients who progressed after one to two lines of next-generation androgen receptor-directed therapy and one taxane-based chemotherapy for mCRPC. Efficacy and safety populations included patients with a deleterious
alteration who received ≥ 1 dose of rucaparib. Key efficacy end points were objective response rate (ORR; per RECIST/Prostate Cancer Clinical Trials Working Group 3 in patients with measurable disease as assessed by blinded, independent radiology review and by investigators) and locally assessed prostate-specific antigen (PSA) response (≥ 50% decrease from baseline) rate.
Efficacy and safety populations included 115 patients with a
alteration with or without measurable disease. Confirmed ORRs per independent radiology review and investigator assessment were 43.5% (95% CI, 31.0% to 56.7%; 27 of 62 patients) and 50.8% (95% CI, 38.1% to 63.4%; 33 of 65 patients), respectively. The confirmed PSA response rate was 54.8% (95% CI, 45.2% to 64.1%; 63 of 115 patients). ORRs were similar for patients with a germline or somatic
alteration and for patients with a
or
alteration, while a higher PSA response rate was observed in patients with a
alteration. The most frequent grade ≥ 3 treatment-emergent adverse event was anemia (25.2%; 29 of 115 patients).
Rucaparib has antitumor activity in patients with mCRPC and a deleterious
alteration, but with a manageable safety profile consistent with that reported in other solid tumor types.
Circulating tumour DNA (ctDNA) analysis facilitates studies of tumour heterogeneity. Here we employ CAPP-Seq ctDNA analysis to study resistance mechanisms in 43 non-small cell lung cancer (NSCLC) ...patients treated with the third-generation epidermal growth factor receptor (EGFR) inhibitor rociletinib. We observe multiple resistance mechanisms in 46% of patients after treatment with first-line inhibitors, indicating frequent intra-patient heterogeneity. Rociletinib resistance recurrently involves MET, EGFR, PIK3CA, ERRB2, KRAS and RB1. We describe a novel EGFR L798I mutation and find that EGFR C797S, which arises in ∼33% of patients after osimertinib treatment, occurs in <3% after rociletinib. Increased MET copy number is the most frequent rociletinib resistance mechanism in this cohort and patients with multiple pre-existing mechanisms (T790M and MET) experience inferior responses. Similarly, rociletinib-resistant xenografts develop MET amplification that can be overcome with the MET inhibitor crizotinib. These results underscore the importance of tumour heterogeneity in NSCLC and the utility of ctDNA-based resistance mechanism assessment.
Metastasis is the leading cause of death in people with lung cancer, yet the molecular effectors underlying tumor dissemination remain poorly defined. Through the development of an in vivo ...spontaneous lung cancer metastasis model, we show that the developmentally regulated transcriptional repressor Capicua (CIC) suppresses invasion and metastasis. Inactivation of CIC relieves repression of its effector ETV4, driving ETV4-mediated upregulation of MMP24, which is necessary and sufficient for metastasis. Loss of CIC, or an increase in levels of its effectors ETV4 and MMP24, is a biomarker of tumor progression and worse outcomes in people with lung and/or gastric cancer. Our findings reveal CIC as a conserved metastasis suppressor, highlighting new anti-metastatic strategies that could potentially improve patient outcomes.
Right hemisphere dominance for visuospatial attention is characteristic of most humans, but its anatomical basis remains unknown. We report the first evidence in humans for a larger parieto-frontal ...network in the right than left hemisphere, and a significant correlation between the degree of anatomical lateralization and asymmetry of performance on visuospatial tasks. Our results suggest that hemispheric specialization is associated with an unbalanced speed of visuospatial processing.
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