(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (19) World Intellectual Property Organization International Bureau (10) International Publication Number (43) International Publication Date WO 2016/081450 Al 26 May 2016 (26.05.2016) W P O P C T (51) International Patent Classification: (81) Designated States (unless otherwise indicated, for every G01N33/574 (2006.01) kind of national protection available): AE, AG, AL, AM, AO, AT, AU, AZ, BA, BB, BG, BH, BN, BR, BW, BY, (21) International Application Number: BZ, CA, CH, CL, CN, CO, CR, CU, CZ, DE, DK, DM, PCT/US20 15/06 1073 DO, DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT, (22) International Filing Date: HN, HR, HU, ID, IL, IN, IR, IS, JP, KE, KG, KN, KP, KR, 17 November 2015 (17.1 1.2015) KZ, LA, LC, LK, LR, LS, LU, LY, MA, MD, ME, MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI, NO, NZ, OM, (25) Filing Language: English PA, PE, PG, PH, PL, PT, QA, RO, RS, RU, RW, SA, SC, (26) Publication Language: English SD, SE, SG, SK, SL, SM, ST, SV, SY, TH, TJ, TM, TN, TR, TT, TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, ZW. (30) Priority Data: 62/08 1,445 18 November 2014 (18. 11.2014) US (84) Designated States (unless otherwise indicated, for every kind of regional protection available): ARIPO (BW, GH, (71) Applicant: BLUEPRINT MEDICINES CORPORA¬ GM, KE, LR, LS, MW, MZ, NA, RW, SD, SL, ST, SZ, TION [US/US]; 215 First Street, Cambridge, MA 02142 TZ, UG, ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, RU, (US). TJ, TM), European (AL, AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT, LU, (72) Inventor: STRANSKY, Nicolas; 12 Lexington Street #2, LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK, Charlestown, MA 02129 (US). SM, TR), OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, GQ, (74) Agents: MCDONELL, Leslie et al; Finnegan, Hender GW, KM, ML, MR, NE, SN, TD, TG). son, Farabow, Garrett &, Dunner, L.L.P., 901 New York Avenue, NW, Washington, DC 20001-4413 (US). Published: — with international search report (Art. 21(3)) © 00 © v © (54) Title: PRKACB FUSIONS (57) Abstract: The invention provides PRKACB gene fiisions, PRKACB fusion proteins, and fragments of those genes and poly- ¾ peptides. The invention further provides methods of diagnosing and treating diseases or disorders associated wiih PRKACB fusions, such as conditions mediated by aberrant PRKACB expression or activity or overexpression of PRKACB. PRKACB FUSIONS [001] This application claims the benefit of U.S. Provisional Application No. 62/081,445, filed November 8, 2 4, which is mcorporated here by reference in its entirety to provide continuity of disclosure. [082] This invention relates to PRKACB (cAMP-dependeni protein kinase catalytic subu it beta) gene fusions and PRKACB fusion proteins. The invention further relates to methods of diagnosing and treating diseases or disorders associated with PRKACB fusions, such as conditions mediated by aberrani PRKACB expression or activiiy, or conditions associ ated with overexpression of PRKACB. [003] Many forms of cancer are caused by genetic lesions that give rise to tumor in i tiation and growth. Genetic lesions may include chromosomal aberrations, such as transloca tions, inversions, deletions, copy number changes, gene expression level changes, and somatic and germline mutations. Indeed, the presence of such genomic aberrations is a hallmark fea ture of many cancers, including, for example, B cell cancer, lung cancer, breast cancer, ovarian cancer, pancreatic cancer, and colon cancer. In some models, cancer represents the phenotypic end-point of multiple genetic lesions that endow cells with a full range of biological properties required for tumorigenesis. [0 4] Recent efforts by The Cancer Genome Atlas (TCGA), the International Cancer Genome Consortium (ICGC), and dozens of other large-scale profiling efforts have generated an enormous amount of new sequencing data for dozens of cancer types - this includes whole- genome DNA, whole-exome DNA, and fuli-transcriptome RNA sequencing. These efforts have led to the identification of new driver genes and fusion genes within multiple cancer types. Fusions, particularly fusions involving kinases, are of particul ar interest, as such fusions have been shown to be oncogenic, and have been successfully targeted by new therapeutics. For example, anaplastic lymphoma kinase (ALK), one of the receptor tyrosine kinases, is known to become oncogenic when fused with various genes. See, e.g., M. Soda et a , "Identi fication of the transforming EML4-ALK fusion gene in non-small-cell lung cancer," Nature 444:561-566 (2007). [085] A need exists for identifying novel genetic lesions associated with cancer. For example, the presence of fusions involving a kinase in samples collected from more than one source can indicate that the kinase is an oncogenic driver. The identification of such fusions can be an effective approach to diagnosis of cancers and development of compounds, composi tions, methods, and assays for evaluating and treating cancer patients. SUMMARY [ 6] In one aspect, the invention provides methods for detecting the presence of a PRKACB fusion in a biological sample; the methods include the steps of: (a) obtaining a bio logical sample from a mammal; and (b) contacting the sample with a reagent that detects a PRKACB fusion, to determine whether a PRKACB fusion is present in the biological sample. In some embodiments, the sample can be from, e.g., a cancer patient. In some embodiments, the cancer is breast cancer. In some embodiments, the cancer is head and neck squamous cell carcinoma. In some embodiments, the fusion can be, e.g., a CEP17():PRKACB fusion, or an RBM17:PRKACB fusion. In some embodiments, the CEP170:PRKACB fusion has ail or a part of the nucleotide and/or amino acid sequence (such as, e.g., the fusion junction) set forth in SEQ ID N O : 1 and SEQ ID O:2, respectively. In some embodiments, the RBM 17:PRKACB fusion has all or part of the nucleotide and/or amino acid sequence (such as, e.g., the fusion junction) set form in SEQ ID NO:3 and SEQ ID NQ:4, respectively. [007] In another aspect, the invention provides methods of diagnosing a patient hav ing a disease or disorder associated with aberrant PRKACB expression or activity, or overex- pression of PRKACB; the methods include: (a) obtaining a biological sample from the patient: and (b) contacting the sample with a reagent that detects a PRKACB fusion to determine whether a PRKACB fusion is present in the biological sample, wherein the detection of the PRKACB fusion indicates the presence of a disorder associated with aberrant PRKACB ex pression or activity, or overexpression of PRKACB. [008] The invention also includes methods of determining a therapeutic regimen for treating a cancer in a human subject; methods of identifying a patient likely to respond to treatment with a PRKACB inhibitor or a PRKACB fusion inhibitor; methods of stratifying a patient population by detecting a PRKACB fusion; methods of treating a patient; methods of inhibiting the proliferation of cells containing a PRKACB fusion; methods of reducing an ac tivity of a PRKACB fusion; methods of treating a condition mediated by aberrant PRKACB expression or activity methods of treating a condition characterized by overexpression of PRKACB; methods of identifying an agent that modulates the activity of a PRKA CB fusion; and methods of monitoring disease burden in a patient having a condition mediated by PRKACB. BRIEF DESCRIPTION OF THE FIGURES [009] FIG. 1 depict the nucleotide sequence of a CEP17():PRKACB gene fusion (SEQ ID O:l ) comprising exons 1-8 of the CEP170 gene (Accession No. M_001042404) and exons 2-10 of the PRKACB gene (Accession No. NM_1 82948). The underlined codons at nucleotides 105- 7 and 11 1- 13 encode the last a ino acid of CEP 1 0 and the first a i no acid of PRKACB, respectively. The slash after nucleotide 08 indicates the breakpoint (fusion junction) where translocation and in- rame fission has occurred. The shading at nucleo tides 08- indicates that nucleotides from both CEP 70 and PRKACB are fused in frame to form a codon and encode an amino acid. [010] FIG. 2 depicts the amino acid sequence of a CEP170:PRKACB fusion protein (SEQ D NQ:2). The shaded amino acid at position 370 corresponds to nucleotides 1 08- in SEQ ID NO: 1. This amino acid is encoded by nucleotides from both CEP 70 and PRKACB. |011 FIG, 3 depicts the nucleotide sequence of an RBM1 7:PRKACB gene fusion (SEQ ID NO:2) comprising exons 1-5 of the RBM17 gene (Accession No. NM_032905) and exons 2- 0 of the PRKACB gene (Accession No. NM 182948). The underlined codons at nu cleotides 502-504 and 508-510 encode the last amino acid of RBM17 and the first amino acid of PRKACB, respectively. The slash after nucleotide 505 indicates the breakpoint (fusion junction) where translocation and in-frame fusion has occurred. The shading at nucleotides 505-507 indicates that nucleotides from both RBM17 and PRKACB are fused in frame to form a codon and encode an amino acid. [012] FIG. 4 depicts the amino acid sequence of an RBMI7:PRKACB fusion pro tein (SEQ ID NO:4). The shaded amino acid at position 69 corresponds to nucleotides 505- 507 in SEQ ID NO:2. This amino acid is encoded by nucleotides from both RBM and PRKACB. EXEMPLARY EMBODIMENTS OF THE INVENTION [013] The invention is based, at least in part, on the discovery of novel recombina tion or translocation events in cancer patients that result in at least a fragment of a PRKACB gene linked to a non-homologous promoter via a recombination or translocation event that may- result in aberrant expression and/or constituti ve activation of PRKACB kinase activity.