Clinical application of genomics- and phosphoproteomics-based selection of targeted therapy in patients with advanced solid tumors

Precision oncology has come a long way since the introduction of the first targeted drug (trastuzumab) in 1999. Broad molecular testing of tumor tissue has vastly expanded our knowledge of the biology of cancer, leading to a steep increase in the number of approved targeted drugs and an expansion of the labeled indications of these drugs. Off-label use of these new classes of targeted drugs is nowadays better documented and often performed in clinical trials to maximize the learning potential of these experimental treatments for the medical community. As long as no “cure for cancer” exists, there will be room for improvement of our knowledge and approach to treating patients with cancer. General improvements in the logistics, availability of targeted drugs and access to diagnostics and expertise will likely have the greatest impact on direct benefit for patients. In the future, standardized processing and conservation of tumor tissue/biopsies should be possible in all healthcare facilities, and collaborations and sharing of knowledge and resources with the academic institutes will be viable to delivering precision oncology to all patients. If these conditions are met, more patients may potentially benefit from the knowledge and new treatment options resulting from the precision oncology trials. Also, medical oncologists may learn more about molecular testing and interpreting test results from participation in MTBs. To maximize the impact of precision oncology, international collaborations are of utmost importance and research groups throughout the world are encouraged to share best practices and creative solutions to overcome the hurdles that still hamper new initiatives in the field today. Future clinical research may focus on prospective therapy selection using molecular information from other –omics fields, such as phosphoproteomics, especially in patients where no clear monogenetic driver mutations is identified and a comprehensive pathway analysis may give more direction for potential therapeutic strategies. More knowledge on the best method of prioritizing targets for treatments will be essential, as well as clinical trials investigating new combinations of targeted agents. With an increasing understanding of cancer biology and improved strategies for treatment selection, precision oncology will be accessible for patients with advanced cancer and more patients will benefit from the knowledge that we gain today and tomorrow. In the future, treatments based on histology alone may be considered old-fashioned, and multi-omics diagnostics may result in a comprehensible report that can be easily interpreted, and will directly guide treatment decisions for individual patients

Patients with Biallelic BRCA1/2 Inactivation respond to Olaparib treatment across Histologic tumor types

Purpose: To assess the efficacy of olaparib, a PARP inhibitor (PARPi) in patients with tumors with BRCA1/2 mutations, regardless of histologic tumor type. Patients and Methods: Patients with treatment-refractory BRCA1/2-mutated cancer were included for treatment with offlabel olaparib 300 mg twice daily until disease progression or unacceptable toxicity. In Drug Rediscovery Protocol (DRUP), patients with treatment-refractory solid malignancies receive offlabel drugs based on tumor molecular profiles while whole-genome sequencing (WGS) is performed on baseline tumor biopsies. The primary endpoint was clinical benefit (CB; defined as objective response or stable disease ≥ 16 weeks according to RECIST 1.1). Per protocol patients were enrolled using a Simon-like two-stage model. Results: Twenty-four evaluable patients with nine different tumor types harboring BRCA1/2 mutations were included, 58% had CB from treatment with olaparib. CB was observed in patients with complete loss of function (LoF) of BRCA1/2, while 73% of patients with biallelic BRCA LoF had CB. In 17 patients with and seven without current labeled indication, 10 and four patients had CB, respectively. Treatment resistance in four patients with biallelic loss might be explained by an additional oncogenic driver which was discovered by WGS, including Wnt pathway activation, FGFR amplification, and CDKN2A loss, in three tumor types. Conclusions: These data indicate that using PARPis is a promising treatment strategy for patients with non-BRCA-associated histologies harboring biallelic BRCA LoF. WGS allows to accurately detect complete LoF of BRCA and homologous repair deficiency (HRD) signature as well as oncogenic drivers that may contribute to resistance, using a single assay

Patients with Rare Cancers in the Drug Rediscovery Protocol (DRUP) Benefit from Genomics-Guided Treatment

Purpose: Patients with rare cancers (incidence less than 6 cases per 100,000 persons per year) commonly have less treatment opportunities and are understudied at the level of genomic targets. We hypothesized that patients with rare cancer benefit from approved anticancer drugs outside their label similar to common cancers. Experimental Design: In the Drug Rediscovery Protocol (DRUP), patients with therapy-refractory metastatic cancers harboring an actionable molecular profile are matched to FDA/European Medicines Agency–approved targeted therapy or immunotherapy. Patients are enrolled in parallel cohorts based on the histologic tumor type, molecular profile and study drug. Primary endpoint is clinical benefit (complete response, partial response, stable disease ≥ 16 weeks). Results: Of 1,145 submitted cases, 500 patients, including 164 patients with rare cancers, started one of the 25 available drugs and were evaluable for treatment outcome. The overall clinical benefit rate was 33% in both the rare cancer and nonrare cancer subgroup. Inactivating alterations of CDKN2A and activating BRAF aberrations were overrepresented in patients with rare cancer compared with nonrare cancers, resulting in more matches to CDK4/6 inhibitors (14% vs. 4%; P ≤ 0.001) or BRAF inhibitors (9% vs. 1%; P ≤ 0.001). Patients with rare cancer treated with small-molecule inhibitors targeting BRAF experienced higher rates of clinical benefit (75%) than the nonrare cancer subgroup. Conclusions: Comprehensive molecular testing in patients with rare cancers may identify treatment opportunities and clinical benefit similar to patients with common cancers. Our findings highlight the importance of access to broad molecular diagnostics to ensure equal treatment opportunities for all patients with cancer

Truncated ETV1, fused to novel tissue-specific genes, and full-length ETV1 in prostate cancer

In this study, we describe the properties of novel ETV1 fusion genes, encoding N-truncated ETV1 (dETV1), and of full-length ETV1, overexpressed in clinical prostate cancer. We detected overexpression of novel ETV1 fusion genes or of full-length ETV1 in 10% of prostate cancers. Novel ETV1 fusion partners included FOXP1, an EST (EST14), and an endogenous retro,viral repeat sequence (HFRVK17). Like TMPRSS2, EST14 and HERVK17 were prostate-specific and androgen-regulated expressed. This unique expression pattern of most ETV1 fusion partners seems an important determinant in prostate cancer development. In transient reporter assays, full-length ETV1 was a strong transactivator, whereas dETV1 was not. However, several of the biological properties of dETV1 and full-length ETV1 were identical. On stable overexpression, both induced migration and invasion of immortalized non-tumorigenic PNT2C2 prostate epithelial cells. In contrast to dETV1, full-length ETV1 also induced anchorage-independent growth of these cells. PNT2C2 cells stably transfected with dETV1 or full-length ETV1 expression constructs showed small differences in induced expression of target genes. Many genes involved in tumor invasion/metastasis, including uPA/uPAR and MMPs, were up-regulated in both cell types. Integrin beta 3 (ITGB3) was clearly up-regulated by full-length ETV1 but much less by dETV1. Based on the present data and on previous findings, a novel concept of the role of dETV1 and of full-length ETV1 overexpression in prostate cancer is proposed

Advancing wide implementation of precision oncology: A liquid nitrogen-free snap freezer preserves molecular profiles of biological samples

Purpose: In precision oncology, tumor molecular profiles guide selection of therapy. Standardized snap freezing of tissue biospecimens is necessary to ensure reproducible, high-quality samples that preserve tumor biology for adequate molecular profiling. Quenching in liquid nitrogen (LN2) is the golden standard method, but LN2 has several limitations. We developed a LN2-independent snap freezer with adjustable cold sink temperature. To benchmark this device against the golden standard, we compared molecular profiles of biospecimens. Methods: Cancer cell lines and core needle normal tissue biopsies from five patients' liver resection specimens were used to compare mass spectrometry (MS)-based global phosphoproteomic and RNA sequencing profiles and RNA integrity obtained by both freezing methods. Results: Unsupervised cluster analysis of phosphoproteomic and transcriptomic profiles of snap freezer versus LN2-frozen K562 samples and liver biopsies showed no separation based on freezing method (with Pearson's r 0.96 (range 0.92–0.98) and >0.99 for K562 profiles, respectively), while samples with +2 h bench-time formed a separate cluster. RNA integrity was also similar for both snap freezing methods. Molecular profiles of liver biopsies were clearly identified per individual patient regardless of the applied freezing method. Two to 25 s freezing time variations did not induce profiling differences in HCT116 samples. Conclusion: The novel snap freezer preserves high-quality biospecimen and allows identification of individual patients' molecular profiles, while overcoming important limitations of the use of LN2. This snap freezer may provide a useful tool in clinical cancer research and practice, enabling a wider implementation of (multi-)omics analyses for precision oncology

Patients with Biallelic BRCA1/2 Inactivation respond to Olaparib treatment across Histologic tumor types

Purpose: To assess the efficacy of olaparib, a PARP inhibitor (PARPi) in patients with tumors with BRCA1/2 mutations, regardless of histologic tumor type. Patients and Methods: Patients with treatment-refractory BRCA1/2-mutated cancer were included for treatment with offlabel olaparib 300 mg twice daily until disease progression or unacceptable toxicity. In Drug Rediscovery Protocol (DRUP), patients with treatment-refractory solid malignancies receive offlabel drugs based on tumor molecular profiles while whole-genome sequencing (WGS) is performed on baseline tumor biopsies. The primary endpoint was clinical benefit (CB; defined as objective response or stable disease ≥ 16 weeks according to RECIST 1.1). Per protocol patients were enrolled using a Simon-like two-stage model. Results: Twenty-four evaluable patients with nine different tumor types harboring BRCA1/2 mutations were included, 58% had CB from treatment with olaparib. CB was observed in patients with complete loss of function (LoF) of BRCA1/2, while 73% of patients with biallelic BRCA LoF had CB. In 17 patients with and seven without current labeled indication, 10 and four patients had CB, respectively. Treatment resistance in four patients with biallelic loss might be explained by an additional oncogenic driver which was discovered by WGS, including Wnt pathway activation, FGFR amplification, and CDKN2A loss, in three tumor types. Conclusions: These data indicate that using PARPis is a promising treatment strategy for patients with non-BRCA-associated histologies harboring biallelic BRCA LoF. WGS allows to accurately detect complete LoF of BRCA and homologous repair deficiency (HRD) signature as well as oncogenic drivers that may contribute to resistance, using a single assay