Triple-negative breast cancer, so called because it lacks expression of the estrogen receptor, progesterone receptor, and HER2, is often, but not always, a basal-like breast cancer. This review focuses on its origin, molecular and clinical characteristics, and treatment.

https://www.nejm.org/doi/pdf/10.1056/NEJMra1001389

Triple-negative breast cancer.

The past 60 years have seen huge advances in many of the scientific, technological and managerial factors that should tend to raise the efficiency of commercial drug research and development (RD). Yet the number of new drugs approved per billion US dollars spent on RD has halved roughly every 9 years since 1950, falling around 80-fold in inflation-adjusted terms. There have been many proposed solutions to the problem of declining RD efficiency. However, their apparent lack of impact so far and the contrast between improving inputs and declining output in terms of the number of new drugs make it sensible to ask whether the underlying problems have been correctly diagnosed. Here, we discuss four factors that we consider to be primary causes, which we call the 'better than the Beatles' problem; the 'cautious regulator' problem; the 'throw money at it' tendency; and the 'basic research-brute force' bias. Our aim is to provoke a more systematic analysis of the causes of the decline in RD efficiency.

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Diagnosing the decline in pharmaceutical R&D efficiency.

Covalent drugs have proved to be successful therapies for various indications, but largely owing to safety concerns, they are rarely considered when initiating a target-directed drug discovery project. There is a need to reassess this important class of drugs, and to reconcile the discordance between the historic success of covalent drugs and the reluctance of most drug discovery teams to include them in their armamentarium. This review surveys the prevalence and pharmacological advantages of covalent drugs, discusses how potential risks and challenges may be addressed through innovative design, and presents the broad opportunities provided by targeted covalent inhibitors.

The resurgence of covalent drugs

Recent findings have thrust poly(ADP-ribose) polymerases (PARPs) into the limelight as potential chemotherapeutic targets. To provide a framework for understanding these recent observations, we review what is known about the structures and functions of the family of PARP enzymes, and then outline a series of questions that should be addressed to guide the rational development of PARP inhibitors as anticancer agents.

PARP inhibition: PARP1 and beyond

Summary Background Olaparib (AZD2281) is a small-molecule, potent oral poly(ADP-ribose) polymerase (PARP) inhibitor. We aimed to assess the safety and tolerability of this drug in patients without BRCA1 or BRCA2 mutations with advanced triple-negative breast cancer or high-grade serous and/or undifferentiated ovarian cancer. Methods In this phase 2, multicentre, open-label, non-randomised study, women with advanced high-grade serous and/or undifferentiated ovarian carcinoma or triple-negative breast cancer were enrolled and received olaparib 400 mg twice a day. Patients were stratified according to whether they had a BRCA1 or BRCA2 mutation or not. The primary endpoint was objective response rate by Response Evaluation Criteria In Solid Tumors (RECIST). All patients who received treatment were included in the analysis of toxic effects, and patients who had measurable lesions at baseline were included in the primary efficacy analysis. This trial is registered at ClinicalTrials.gov, number NCT00679783. Findings 91 patients were enrolled (65 with ovarian cancer and 26 breast cancer) and 90 were treated between July 8, 2008, and Sept 24, 2009. In the ovarian cancer cohorts, 64 patients received treatment. 63 patients had target lesions and therefore were evaluable for objective response as per RECIST. In these patients, confirmed objective responses were seen in seven (41%; 95% CI 22–64) of 17 patients with BRCA1 or BRCA2 mutations and 11 (24%; 14–38) of 46 without mutations. No confirmed objective responses were reported in patients with breast cancer. The most common adverse events were fatigue (45 [70%] of patients with ovarian cancer, 13 [50%] of patients with breast cancer), nausea (42 [66%] and 16 [62%]), vomiting (25 [39%] and nine [35%]), and decreased appetite (23 [36%] and seven [27%]). Interpretation Our study suggests that olaparib is a promising treatment for women with ovarian cancer and further assessment of the drug in clinical trials is needed. Funding AstraZeneca.

https://www.thelancet.com/pdfs/journals/lanonc/PIIS1470-2045(11)70214-5.pdf

Olaparib in patients with recurrent high-grade serous or poorly differentiated ovarian carcinoma or triple-negative breast cancer: a phase 2, multicentre, open-label, non-randomised study

Background Triple-negative breast cancers have inherent defects in DNA repair, making this cancer a rational target for therapy based on poly(adenosine diphosphate–ribose) polymerase (PARP) inhibition. Methods We conducted an open-label, phase 2 study to compare the efficacy and safety of gemcitabine and carboplatin with or without iniparib, a small molecule with PARP-inhibitory activity, in patients with metastatic triple-negative breast cancer. A total of 123 patients were randomly assigned to receive gemcitabine (1000 mg per square meter of body-surface area) and carboplatin (at a dose equivalent to an area under the concentration–time curve of 2) on days 1 and 8 — with or without iniparib (at a dose of 5.6 mg per kilogram of body weight) on days 1, 4, 8, and 11 — every 21 days. Primary end points were the rate of clinical benefit (i.e., the rate of objective response [complete or partial response] plus the rate of stable disease for ≥6 months) and safety. Additional end points included the rate of obj...

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Iniparib plus Chemotherapy in Metastatic Triple-Negative Breast Cancer

In one aspect, the present invention provides a method of treating breast cancer that is negative for at least one of ER, PR, or HER2, comprising administering to a subject at least one PARP inhibitor. In another aspect, the present invention provides a method of treating breast cancer comprising administering to a subject at least one PARP inhibitor in combination with at least one anti-tumor agent.

Treatment of breast cancer with a parp inhibitor alone or in combination with anti-tumor agents

Background: TNBC is an aggressive breast cancer subtype which shares molecular and pathologic features with BRCA1-related breast cancers. BRCA-deficient cells are sensitive to inhibition of PARP1, a critical enzyme of cell proliferation and DNA repair, and thus represent a rational target of PARP inhibitor-based cancer therapy. The objectives of this study were to evaluate BSI-201, a potent PARP1 inhibitor, in combination with G/C in subjects with metastatic TNBC. Methods: Eligible subjects had measurable disease and received ≤2 prior cytotoxic regimens for ER-, PR-, and HER2-negative metastatic breast cancer. Patients were randomized (1:1) to G/C alone or G/C + BSI-201. Gemcitabine (1000 mg/m2; IV) and carboplatin (AUC = 2; IV) were given on days 1 and 8, and BSI-201 (5.6 mg/kg; IV) on days 1, 4, 8, and 11 every 21 days. Endpoints were clinical benefit rate (CBR = CR + PR + SD ≥6 months), objective response rate (ORR), progression-free survival (PFS) and overall survival (OS). Results: Preliminary analyses of all 116 dosed patients showed that, based on all patient visits through March 2009, BSI-201 + G/C improved CBR, ORR, median PFS, and median OS, compared with G/C alone. The frequency and nature of adverse events did not differ between arms.Conclusions: This analysis demonstrates that BSI-201 + G/C improved patient9s outcomes, as measured by CBR, ORR, PFS and OS, compared with G/C alone. BSI-201 + gemcitabine/carboplatin was well tolerated and did not potentiate chemotherapy-related toxicities. Final data on CBR and ORR, as well as updated analyses of PFS and OS for all 116 dosed patients will be presented based on all patient visits through September 2009. Exploratory correlative analyses of PARP expression and overall clinical response will also be presented, as well as initial correlative analyses between number of metastatic therapies and clinical response. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3122.

Final Results of a Randomized Phase II Study Demonstrating Efficacy and Safety of BSI-201, a Poly (ADP-Ribose) Polymerase (PARP) Inhibitor, in Combination with Gemcitabine/Carboplatin (G/C) in Metastatic Triple Negative Breast Cancer (TNBC).

In one aspect, the present invention provides a composition and a kit comprising a combination of topoisomerase inhibitor and PARP inhibitor for treatment of cancer. In another aspect, the invention provides a method of treating cancer comprising administering to a subject a combination of topoisomerase inhibitor and PARP inhibitor. In particular, the invention provides compositions and methods for treating cancer in a subject by inhibiting a poly-ADP-ribose polymerase and a topoisomerase, as well as providing formulations and modes of administering such compositions.

Treatment of cancer with combinations of topoisomerase inhibitors and parp inhibitors

In one aspect, the present invention provides a method of treating uterine cancer, endometrial cancer, or ovarian cancer, comprising administering to a subject at least one PARP inhibitor. In another aspect, the present invention provides a method of treating uterine cancer, endometrial cancer, or ovarian cancer, comprising administering to a subject at least one PARP inhibitor in combination with at least one anti-tumor agent.

Charles Bradley

Papers

Iniparib plus Chemotherapy in Metastatic Triple-Negative Breast Cancer

Treatment of breast cancer with a parp inhibitor alone or in combination with anti-tumor agents

Final Results of a Randomized Phase II Study Demonstrating Efficacy and Safety of BSI-201, a Poly (ADP-Ribose) Polymerase (PARP) Inhibitor, in Combination with Gemcitabine/Carboplatin (G/C) in Metastatic Triple Negative Breast Cancer (TNBC).

Treatment of cancer with combinations of topoisomerase inhibitors and parp inhibitors

Treatment of uterine cancer and ovarian cancer with a parp inhibitor alone or in combination with anti-tumor agents