Drug discovery in advanced prostate cancer: translating biology into therapy.

Castration-resistant prostate cancer (CRPC) is associated with a poor prognosis and poses considerable therapeutic challenges. Recent genetic and technological advances have provided insights into prostate cancer biology and have enabled the identification of novel drug targets and potent molecularly targeted therapeutics for this disease. In this article, we review recent advances in prostate cancer target identification for drug discovery and discuss their promise and associated challenges. We review the evolving therapeutic landscape of CRPC and discuss issues associated with precision medicine as well as challenges encountered with immunotherapy for this disease. Finally, we envision the future management of CRPC, highlighting the use of circulating biomarkers and modern clinical trial designs

Pancreatic cancer: optimizing treatment options, new, and emerging targeted therapies

Elena Gabriela Chiorean, Andrew L Coveler Department of Medicine, Division of Oncology, University of Washington, Seattle, WA, USA Abstract: Pancreatic cancer is the fourth leading cause of cancer death in the US and is expected to become the second leading cause of cancer-related deaths in the next decade. Despite 5-fluorouracil/leucovorin with irinotecan and oxaliplatin (FOLFIRINOX) and gemcitabine/nab-paclitaxel significantly improving outcomes for metastatic cancer, refractory disease still poses significant challenges. Difficulties with early detection and the inherent chemo- and radio-resistant nature of this malignancy led to attempts to define the sequential biology of pancreatic cancer in order to improve survival outcomes. Pancreatic adenocarcinoma is characterized by several germline or acquired genetic mutations, the most common being KRAS (90%), CDK2NA (90%), TP53 (75%–90%), DPC4/SMAD4 (50%). In addition, the tumor microenvironment, chemoresistant cancer stem cells, and the desmoplastic stroma have been the target of some promising clinical investigations. Among the core pathways reproducibly shown to lead the development and progression of this disease, DNA repair, apoptosis, G1/S cell cycle transition, KRAS, Wnt, Notch, Hedgehog, TGF-beta, and other cell invasion pathways, have been the target of “precision therapeutics”. No single molecularly targeted therapeutic though has been uniformly successful, probably due to the tumor heterogeneity, but biomarker research is evolving and it hopes to select more patients likely to benefit. Recent reports note activity with immunotherapies such as CD40 agonists, CCR2 inhibitors, cancer vaccines, and novel combinations against the immunosuppressive tumor milieu are ongoing. While many obstacles still exist, clearly we are making progress in deciphering the heterogeneity within pancreatic cancers. Integrating conventional and immunological targeting will be the key to effective treatment of this deadly disease. Keywords: pancreatic cancer, immunotherapies, signaling pathway inhibitors, targeted therapie

Performance status dynamics during treatment with nab-paclitaxel plus gemcitabine versus gemcitabine alone for metastatic pancreatic cancer

Objectives: This analysis examined changes in Karnofsky performance status (KPS) as a surrogate for patient’s well-being during treatment with nab-paclitaxel plus gemcitabine vs gemcitabine alone as first-line therapy for metastatic pancreatic cancer (MPC) in the Phase III MPACT trial. Participants and methods: Descriptive analyses were performed for KPS at three time points (3 and 6 months after randomization and 1 month before disease progression) and for time to any KPS deterioration. Time to definitive KPS deterioration (≥10-point KPS decrease from baseline) was calculated using the Kaplan-Meier method. A larger decrease from baseline (≥20 points) was investigated as a sensitivity analysis. A Cox proportional hazards model analyzed the effect of baseline factors (including treatment) potentially associated with time to definitive deterioration. Results: The two treatment arms had generally comparable time to any KPS deterioration, similar KPS at 3 and 6 months after randomization and at 1 month before disease progression, and no significant difference in time to definitive deterioration. Baseline KPS, neutrophil-tolymphocyte ratio, age, liver metastases, and region had a significant effect on time to definitive KPS deterioration, but treatment arm did not. Conclusion: The increased survival observed with nab-paclitaxel plus gemcitabine was not associated with adverse effects on performance status

Performance status dynamics during treatment with nab-paclitaxel plus gemcitabine versus gemcitabine alone for metastatic pancreatic cancer

E Gabriela Chiorean,1 Daniel Von Hoff,2 Yin Wan,3 Sandra Margunato-Debay,4 Marc Botteman,3 David Goldstein5 1Medical Oncology, Fred Hutchinson Cancer Research Center, University of Washington, Seattle, WA, 2Oncology, Translational Genomics Research Institute and HonorHealth, Phoenix, AZ, 3Pharmerit International, Bethesda, MD, 4Celgene Corporation, Summit, NJ, USA; 5Department of Medical Oncology, Prince of Wales Hospital, Sydney, NSW, Australia Objectives: This analysis examined changes in Karnofsky performance status (KPS) as a surrogate for patient’s well-being during treatment with nab-paclitaxel plus gemcitabine vs gemcitabine alone as first-line therapy for metastatic pancreatic cancer (MPC) in the Phase III MPACT trial.Participants and methods: Descriptive analyses were performed for KPS at three time points (3 and 6 months after randomization and 1 month before disease progression) and for time to any KPS deterioration. Time to definitive KPS deterioration (≥10-point KPS decrease from baseline) was calculated using the Kaplan–Meier method. A larger decrease from baseline (≥20 points) was investigated as a sensitivity analysis. A Cox proportional hazards model analyzed the effect of baseline factors (including treatment) potentially associated with time to definitive deterioration.Results: The two treatment arms had generally comparable time to any KPS deterioration, similar KPS at 3 and 6 months after randomization and at 1 month before disease progression, and no significant difference in time to definitive deterioration. Baseline KPS, neutrophil-to-lymphocyte ratio, age, liver metastases, and region had a significant effect on time to definitive KPS deterioration, but treatment arm did not.Conclusion: The increased survival observed with nab-paclitaxel plus gemcitabine was not associated with adverse effects on performance status. Keywords: Karnofsky performance status, metastatic pancreatic cancer, chemotherapy, nab-paclitaxel, gemcitabin

Second-line therapy after nab-paclitaxel plus gemcitabine or after gemcitabine for patients with metastatic pancreatic cancer

Background: This exploratory analysis evaluated second-line (2L) therapy for metastatic pancreatic cancer in a large phase 3 trial (MPACT). Methods: Patients who received first-line (1L) nab-paclitaxel+gemcitabine (nab-P+Gem) or Gem were assessed for survival based on 2L treatment received. Multivariate analyses tested influence of treatment effect and prognostic factors on survival. Results: The majority of 2L treatments (267 out of 347, 77%) contained a fluoropyrimidine (5-fluorouracil or capecitabine). Median total survival (1L randomisation to death) for patients who received 2L treatment after 1L nab-P+Gem vs Gem alone was 12.8 vs 9.9 months (P=0.015). Median total survival for patients with a fluoropyrimidine-containing 2L therapy after nab-P+Gem vs Gem was 13.5 vs 9.5 months (P=0.012). Median 2L survival (duration from start of 2L therapy to death) was 5.3 vs 4.5 months for nab-P+Gem vs Gem, respectively (P=0.886). Factors significantly associated with longer post-1L survival by multivariate analyses included 1L nab-P+Gem, receiving 2L treatment, longer 1L progression-free survival, and Karnofsky performance status≥70 and neutrophil-to-lymphocyte ratio≤5 at the end of 1L treatment. Conclusions: These findings support the use of 2L therapy for patients with metastatic pancreatic cancer. Fluoropyrimidine-containing treatment after 1L nab-P+Gem is an active regimen with significant clinical effect

CA19-9 decrease at 8 weeks as a predictor of overall survival in a randomized phase III trial (MPACT) of weekly nab-paclitaxel plus gemcitabine versus gemcitabine alone in patients with metastatic pancreatic cancer

Background: A phase I/II study and subsequent phase III study (MPACT) reported significant correlations between CA19-9 decreases and prolonged overall survival (OS) with nab-paclitaxel plus gemcitabine (nab-P + Gem) treatment for metastatic pancreatic cancer (MPC). CA19-9 changes at week 8 and potential associations with efficacy were investigated as part of an exploratory analysis in the MPACT trial. Patients and methods: Untreated patients with MPC (N = 861) received nab-P + Gem or Gem alone. CA19-9 was evaluated at baseline and every 8 weeks. Results: Patients with baseline and week-8 CA19-9 measurements were analyzed (nab-P + Gem: 252; Gem: 202). In an analysis pooling the treatments, patients with any CA19-9 decline (80%) versus those without (20%) had improved OS (median 11.1 versus 8.0 months; P = 0.005). In the nab-P + Gem arm, patients with (n = 206) versus without (n = 46) any CA19-9 decrease at week 8 had a confirmed overall response rate (ORR) of 40% versus 13%, and a median OS of 13.2 versus 8.3 months (P = 0.001), respectively. In the Gem-alone arm, patients with (n = 159) versus without (n = 43) CA19- 9 decrease at week 8 had a confirmed ORR of 15% versus 5%, and a median OS of 9.4 versus 7.1 months (P = 0.404), respectively. In the nab-P + Gem and Gem-alone arms, by week 8, 16% (40/252) and 6% (13/202) of patients, respectively, had an unconfirmed radiologic response (median OS 13.7 and 14.7 months, respectively), and 79% and 84% of patients, respectively, had stable disease (SD) (median OS 11.1 and 9 months, respectively). Patients with SD and any CA19-9 decrease (158/199 and 133/170) had a median OS of 13.2 and 9.4 months, respectively. Conclusion: This analysis demonstrated that, in patients with MPC, any CA19-9 decrease at week 8 can be an early marker for chemotherapy efficacy, including in those patients with SD. CA19-9 decrease identified more patients with survival benefit than radiologic response by week 8

The PI3K Pathway As Drug Target in Human Cancer

The phosphatidylinositol 3-kinase (PI3K) signaling axis impacts on cancer cell growth, survival, motility, and metabolism. This pathway is activated by several different mechanisms in cancers, including somatic mutation and amplification of genes encoding key components. In addition, PI3K signaling may serve integral functions for noncancerous cells in the tumor microenvironment. Consequently, therapeutics targeting the PI3K pathway are being developed at a rapid pace, and preclinical and early clinical studies are beginning to suggest specific strategies to effectively use them. However, the central role of PI3K signaling in a large array of diverse biologic processes raises concerns about its use in therapeutics and increases the need to develop sophisticated strategies for its use. In this review, we will discuss how PI3K signaling affects the growth and survival of tumor cells. From this vantage, we will consider how inhibitors of the PI3K signaling cascade, either alone or in combination with other therapeutics, can most effectively be used for the treatment of cancer