A B7-H4-Targeting Antibody-Drug Conjugate Shows Antitumor Activity in PARPi and Platinum-Resistant Cancers with B7-H4 Expression.

PURPOSE: Platinum and PARP inhibitors (PARPi) demonstrate activity in breast and ovarian cancers, but drug resistance ultimately emerges. Here, we examine B7-H4 expression in primary and recurrent high-grade serous ovarian carcinoma (HGSOC) and the activity of a B7-H4-directed antibody-drug conjugate (B7-H4-ADC), using a pyrrolobenzodiazepine-dimer payload, in PARPi- and platinum-resistant HGSOC patient-derived xenograft (PDX) models. EXPERIMENTAL DESIGN: B7-H4 expression was quantified by flow cytometry and IHC. B7-H4-ADC efficacy was tested against multiple cell lines in vitro and PDX in vivo. The effect of B7-H4-ADC on cell cycle, DNA damage, and apoptosis was measured using flow cytometry. RESULTS: B7-H4 is overexpressed in 92% of HGSOC tumors at diagnosis (n = 12), persisted in recurrent matched samples after platinum treatment, and was expressed at similar levels across metastatic sites after acquired multi-drug resistance (n = 4). Treatment with B7-H4-ADC resulted in target-specific growth inhibition of multiple ovarian and breast cancer cell lines. In platinum- or PARPi-resistant ovarian cancer cells, B7-H4-ADC significantly decreased viability and colony formation while increasing cell-cycle arrest and DNA damage, ultimately leading to apoptosis. Single-dose B7-H4-ADC led to tumor regression in 65.5% of breast and ovarian PDX models (n = 29), with reduced activity in B7-H4 low or negative models. In PARPi and platinum-resistant HGSOC PDX models, scheduled B7-H4-ADC dosing led to sustained tumor regression and increased survival. CONCLUSIONS: These data support B7-H4 as an attractive ADC target for treatment of drug-resistant HGSOC and provide evidence for activity of an ADC with a DNA-damaging payload in this population. See related commentary by Veneziani et al., p. 1434.

Dual blockade of BRD4 and ATR/WEE1 pathways exploits ARID1A loss in clear cell ovarian cancer.

ARID1A, an epigenetic tumor suppressor, is the most common gene mutation in clear-cell ovarian cancers (CCOCs). CCOCs are often resistant to standard chemotherapy and lack effective therapies. We hypothesized that ARID1A loss would increase CCOC cell dependency on chromatin remodeling and DNA repair pathways for survival. We demonstrate that combining BRD4 inhibitor (BRD4i) with DNA damage response inhibitors (ATR or WEE1 inhibitors; e.g. BRD4i-ATRi) was synergistic at low doses leading to decreased survival, and colony formation in CCOC in an ARID1A dependent manner. BRD4i-ATRi caused significant tumor regression and increased overall survival in ARID1AMUT but not ARID1AWT patient-derived xenografts. Combination BRD4i-ATRi significantly increased γH2AX, and decreased RAD51 foci and BRCA1 expression, suggesting decreased ability to repair DNA double-strand-breaks (DSBs) by homologous-recombination in ARID1AMUT cells, and these effects were greater than monotherapies. These studies demonstrate BRD4i-ATRi is an effective treatment strategy that capitalizes on synthetic lethality with ARID1A loss in CCOC.

Phase 1 trial of nelfinavir added to standard cisplatin chemotherapy with concurrent pelvic radiation for locally advanced cervical cancer.

BACKGROUND: Nelfinavir (NFV), an HIV-1 protease inhibitor, has been shown to sensitize cancer cells to chemoradiation (CRT). The objectives of this phase 1 trial were to evaluate safety and identify the recommended phase 2 dose of NFV added to concurrent CRT for locally advanced cervical cancer. METHODS: Two dose levels of NFV were evaluated: 875 mg orally twice daily (dose level 1 [DL1]) and 1250 mg twice daily (DL2). NFV was initiated 7 days before CRT and continued through CRT completion. Toxicity, radiographic responses, and pathologic responses were evaluated. Serial tumor biopsies (baseline, after NFV monotherapy, on NFV + CRT, and posttreatment) were evaluated by immunohistochemistry, NanoString, and reverse-phase-protein-array analyses. RESULTS: NFV sensitized cervical cancer cells to radiation, increasing apoptosis and tumor suppression in vivo. Patients (n = 13) with International Federation of Gynecology and Obstetrics stage IIA through IVA squamous cell cervical carcinoma were enrolled, including 7 patients at DL1 and 6 patients at DL2. At DL1, expansion to 6 patients was required after a patient developed a dose-limiting toxicity, whereas no dose-limiting toxicities occurred at DL2. Therefore, DL2 was established as the recommended phase 2 dose. All patients at DL2 completed CRT, and 1 of 6 experienced grade 3 or 4 anemia, nausea, and diarrhea. One recurrence was noted at DL2, with disease outside the radiation field. Ten of 11 evaluable patients remained without evidence of disease at a median follow-up of 50 months. NFV significantly decreased phosphorylated Akt levels in tumors. Cell cycle and cancer pathways also were reduced by NFV and CRT. CONCLUSIONS: NFV with CRT is well tolerated. The response rate is promising compared with historic controls in this patient population and warrants further investigation.

Ten-Year Comparison Study of Type 1 and 2 Endometrial Cancers: Risk Factors and Outcomes.

AIMS: To compare baseline risk factors for type 1 vs. 2 endometrial cancers and analyze these risk factors for association with overall survival and time to recurrence. METHODS: Retrospective review of 816 consecutive endometrial cancer cases was conducted with diagnosis from January 2005 to December 2010 and clinical course until 2016. Risk factors, treatment, recurrence, and death were compared using 2 sample t tests, χ2 test and Cox Regression models. RESULTS: There were 550 cases of type 1 and 266 cases of type 2 cancer. Patients with type 2 disease were older (p < 0.001), less obese (p = 0.03), non-white (p < 0.001), and menopausal (p = 0.02). There was no difference in use of oral contraceptives, hormone replacement therapy (HRT), smoking, or major cardiovascular disease. Cox Regression models showed that type 2 disease (p < 0.001) and advanced stage (p = 0.001) were associated with recurrence. CONCLUSIONS: Consistent with previous literature, our analysis found that type 2 cancer is more common in non-white, older, and less obese patients and associated with higher mortality and recurrence. However, inconsistent with previous literature, we found no association between type 2 cancer and diabetes mellitus or use of HRT. These factors should be considered when approaching patients with endometrial cancer.

Associated characteristics and impact on recurrence and survival of free-floating tumor fragments in the lumen of fallopian tubes in Type I and Type II endometrial cancer.

OBJECTIVE: This study sought to evaluate characteristics of cases of free-floating tumor fragments within the lumen of fallopian tubes ('floaters') on final pathology for Type I and Type II endometrial adenocarcinoma, including relationships with disease recurrence and mortality. METHODS: A single institution experience of 1022 consecutive cases of uterine cancer presenting between 2005 and 2010 was retrospectively reviewed, with data extraction from electronic medical records. Associations of floaters with baseline characteristics were studied with logistic regression, and relationships with disease recurrence and survival were assessed with Cox proportional hazards models. RESULTS: Among 816 included cases of Type I or Type II endometrial adenocarcinoma, floaters were identified on final pathology for 20 patients (2.5%). Patient characteristics of cases with floaters mirrored the overall sample. With adjustment, presence of floaters trended towards association with laparoscopic/robotic approach (OR = 3.84; 95%CI 0.98-15.1), and was significantly associated with lymphovascular invasion (OR = 9.65; 95%CI 2.35-39.6) and higher stage disease. Although floaters were associated with increased risk of recurrence in unadjusted analysis (HR = 3.22; 95%CI 1.41-7.37), after adjustment for disease type, stage, and patient comorbidities, no evidence for impact on disease recurrence or overall survival was found. CONCLUSIONS: The presence of floaters is rare. Floaters were generally associated with more extensive disease, but no evidence was found to show any independent prognostic impact on risk of recurrence or death. In agreement with prior research, this study found a trend towards association of floaters with laparoscopic/robotic approach, indicating the possibility of floaters sometimes being the result of trauma from uterine manipulator insertion.

The management of sexuality, intimacy, and menopause symptoms (SIMS) after prophylactic bilateral salpingo-oophorectomy: How to maintain sexual health in "previvors".

"Previvors", or "pre-survivors", are individuals who do not have cancer but have a genetic predisposition to cancer. One such example is women with BRCA mutations. As a result of their predisposition to cancer, many will undergo a bilateral salpingo-oophorectomy when they are premenopausal. For premenopausal women, the removal of ovaries results in the depletion of estrogen, immediate menopause, and, in many cases, resultant Sexuality, Intimacy, and Menopausal Symptoms (SIMS). Furthermore, they may undergo changes in body image. SIMS are underreported by patients and underdiagnosed by practitioners. At the time of diagnosis or at preoperative visits, women should be informed of the potential physiologic, hormonal, and psychosocial effects of their risk-reducing surgery. There are many modalities for management of these symptoms. Successful treatment requires the provider's awareness of the problem, ability to identify it, and willingness to treat it.

Management of sexuality, intimacy, and menopause symptoms in patients with ovarian cancer.

Issues of sexuality, intimacy, and early menopause significantly impact the quality of life of patients following the diagnosis and treatment of ovarian cancer. These are undertreated problems. Successful treatment requires the provider's awareness of the problem, ability to identify it, and willingness to treat it. Unfortunately many providers do not address these issues in the pretreatment or perioperative period. Furthermore, patients do not often alert their providers to their symptoms. While systemic hormone therapy may improve many of the issues, they are not appropriate for all patients given their action on estrogen receptors. However, other nonhormonal treatments exist including selective serotonin reuptake inhibitors, antiepileptics, natural remedies, and pelvic floor physical therapy. In addition psychological care and the involvement of the partner can be helpful in managing the sexual health concerns of these patients. At the time of diagnosis or at initial consultation, women should be informed of the potential physiologic, hormonal, and psychosocial effects of ovarian cancer on sexuality and that there is a multimodal approach to dealing with symptoms.

MK-2206 sensitizes BRCA-deficient epithelial ovarian adenocarcinoma to cisplatin and olaparib.

BACKGROUND: Platinum resistance is a major obstacle in the treatment of epithelial ovarian cancer (EOC). Activation of the AKT pathway promotes platinum resistance while inhibition of AKT sensitizes chemoresistant cells. Patients with BRCA mutant EOC, and thus a defect in the homologous recombination (HR) repair pathway, demonstrate greater clinical response to platinum and olaparib therapy than patients with BRCA wild-type EOC. MK-2206, an allosteric inhibitor of AKT phosphorylation, sensitizes a variety of cell types to various anticancer agents and is currently undergoing phase II trials as monotherapy for platinum-resistant ovarian, fallopian tube, and peritoneal cancer. This study examines the differential effects of AKT inhibition with cisplatin and olaparib therapy in BRCA1/2-deficient versus wild-type EOC. METHODS: PEO1, a chemosensitive BRCA2-mutant serous ovarian adenocarcinoma, and PEO4, a reverted BRCA2-proficient line from the same patient after the development of chemotherapeutic resistance, were primarily used for the study. In PEO1, MK-2206 demonstrated moderate to strong synergism with cisplatin and olaparib at all doses, while demonstrating antagonism at all doses in PEO4. RESULTS: Baseline phospho-AKT activity in untreated cells was upregulated in both BRCA1- and 2-deficient cell lines. MK-2206 prevented cisplatin- and olaparib-induced AKT activation in the BRCA2-deficient PEO1 cells. We propose that BRCA-deficient EOC cells upregulate baseline AKT activity to enhance survival in the absence of HR. Higher AKT activity is also required to withstand cytotoxic agent-induced DNA damage, leading to strong synergism between MK-2206 and cisplatin or olaparib therapy in BRCA-deficient cells. CONCLUSIONS: MK-2206 shows promise as a chemosensitization agent in BRCA-deficient EOC and merits clinical investigation in this patient population.

Triapine potentiates platinum-based combination therapy by disruption of homologous recombination repair.

BACKGROUND: Platinum resistance may be attributable to inherent or acquired proficiency in homologous recombination repair (HRR) in epithelial ovarian cancer (EOC). The objective of this study was to evaluate the efficacy of the small molecule inhibitor triapine to disrupt HRR and sensitise BRCA wild-type EOC cells to platinum-based combination therapy in vitro and in vivo. METHODS: The sensitivity of BRCA wild-type cancer cells to olaparib, cisplatin, carboplatin, doxorubicin, or etoposide in combination with triapine was evaluated by clonogenic survival assays. The effects of triapine on HRR activity in cells were measured with a DR-GFP reporter assay. The ability of triapine to enhance the effects of the carboplatin-doxil combination on EOC tumour growth delay was determined using a xenograft tumour mouse model. RESULTS: Platinum resistance is associated with wild-type BRCA status. Triapine inhibits HRR activity and enhances the sensitivity of BRCA wild-type cancer cells to cisplatin, olaparib, and doxorubicin. However, sequential combination of triapine and cisplatin is necessary to achieve synergism. Moreover, triapine potentiates platinum-based combination therapy against BRCA wild-type EOC cells and produces significant delay of EOC tumour growth. CONCLUSIONS: Triapine promises to augment the clinical efficacy of platinum-based combination regimens for treatment of platinum-resistant EOC with wild-type BRCA and proficient HRR activity.

Triapine disrupts CtIP-mediated homologous recombination repair and sensitizes ovarian cancer cells to PARP and topoisomerase inhibitors.

UNLABELLED: PARP inhibitors exploit synthetic lethality to target epithelial ovarian cancer (EOC) with hereditary BRCA mutations and defects in homologous recombination repair (HRR). However, such an approach is limited to a small subset of EOC patients and compromised by restored HRR due to secondary mutations in BRCA genes. Here, it was demonstrated that triapine, a small-molecule inhibitor of ribonucleotide reductase, enhances the sensitivity of BRCA wild-type EOC cells to the PARP inhibitor olaparib and the topoisomerase II inhibitor etoposide. Triapine abolishes olaparib-induced BRCA1 and Rad51 foci, and disrupts the BRCA1 interaction with the Mre11-Rad50-Nbs1 (MRN) complex in BRCA1 wild-type EOC cells. It has been shown that phosphorylation of CtIP (RBBP8) is required for the interaction with BRCA1 and with MRN to promote DNA double-strand break (DSB) resection during S and G(2) phases of the cell cycle. Mechanistic studies within reveal that triapine inhibits cyclin-dependent kinase (CDK) activity and blocks olaparib-induced CtIP phosphorylation through Chk1 activation. Furthermore, triapine abrogates etoposide-induced CtIP phosphorylation and DSB resection as evidenced by marked attenuation of RPA32 phosphorylation. Concurrently, triapine obliterates etoposide-induced BRCA1 foci and sensitizes BRCA1 wild-type EOC cells to etoposide. Using a GFP-based HRR assay, it was determined that triapine suppresses HRR activity induced by an I-SceI-generated DSB. These results suggest that triapine augments the sensitivity of BRCA wild-type EOC cells to drug-induced DSBs by disrupting CtIP-mediated HRR. IMPLICATIONS: These findings provide a strong rationale for combining triapine with PARP or topoisomerase inhibitors to target HRR-proficient EOC cells.

Efficacy and safety of higher dose stereotactic radiosurgery for functional pituitary adenomas: a preliminary report.

OBJECTIVE: Single fraction stereotactic radiosurgery (SRS) is a common adjuvant therapy for hormonally active pituitary adenomas when surgical resection fails to control tumor growth or normalize hypersecretory activity. Marginal doses of 20-24 Gy are used at many centers and here we report our outcome data in patients treated with a higher marginal dose of 35 Gy. METHODS: Thirty-one patients with secretory pituitary adenomas (adrenocorticotropic hormone, n = 15; growth hormone, n = 13; prolactin, n = 2; thyroid-stimulating hormone, n = 1) were treated with 35 Gy to the 50% isodose line, and had a mean follow-up time of 40.2 months (range = 12-96). All patients were evaluated post-SRS for time to hormonal normalization, time to relapse, as well as incidence and time course of radiation-induced hypopituitarism and cranial neuropathies. RESULTS: Initial normalization of hypersecretion was achieved in 22 patients (70%) with a median time to remission of 17.7 months. After initial hormonal remission, 7 patients (32%) experienced an endocrine relapse, with a mean time to relapse of 21 months. New endocrine deficiency within any of the five major hormonal axes occurred in 10 patients (32%). One patient (3%) developed new-onset unilateral optic nerve pallor within the temporal field 3 years after SRS. Three patients (10%) reported transient new or increasing frontal headaches of unclear etiology following their procedures. CONCLUSION: Time to endocrine remission was more rapid in patients treated with 35 Gy, as compared to previously reported literature using marginal doses of 20-24 Gy. Rates of endocrine remission and relapse, post-SRS hypopituitarism, and radiation-induced sequelae were not increased following higher dose treatment.