A Closer Look at EGFR Inhibitor Resistance in Non-Small Cell Lung Cancer through the Lens of Precision Medicine.

The development of EGFR small-molecule inhibitors has provided significant benefit for the affected patient population. Unfortunately, current inhibitors are no curative therapy, and their development has been driven by on-target mutations that interfere with binding and thus inhibitory activity. Genomic studies have revealed that, in addition to these on-target mutations, there are also multiple off-target mechanisms of EGFR inhibitor resistance and novel therapeutics that can overcome these challenges are sought. Resistance to competitive 1st-generation and covalent 2nd- and 3rd-generation EGFR inhibitors is overall more complex than initially thought, and novel 4th-generation allosteric inhibitors are expected to suffer from a similar fate. Additional nongenetic mechanisms of resistance are significant and can include up to 50% of the escape pathways. These potential targets have gained recent interest and are usually not part of cancer panels that look for alterations in resistant patient specimen. We discuss the duality between genetic and nongenetic EGFR inhibitor drug resistance and summarize current team medicine approaches, wherein clinical developments, hand in hand with drug development research, drive potential opportunities for combination therapy.

Frontline Management of Epithelial Ovarian Cancer-Combining Clinical Expertise with Community Practice Collaboration and Cutting-Edge Research.

Epithelial ovarian cancer (EOC) is the most common histology of ovarian cancer defined as epithelial cancer derived from the ovaries, fallopian tubes, or primary peritoneum. It is the fifth most common cause of cancer-related death in women in the United States. Because of a lack of effective screening and non-specific symptoms, EOC is typically diagnosed at an advanced stage (FIGO stage III or IV) and approximately one third of patients have malignant ascites at initial presentation. The treatment of ovarian cancer consists of a combination of cytoreductive surgery and systemic chemotherapy. Despite the advances with new cytotoxic and targeted therapies, the five-year survival rate for all-stage EOC in the United States is 48.6%. Delivery of up-to-date guideline care and multidisciplinary team efforts are important drivers of overall survival. In this paper, we review our frontline management of EOC that relies on a multi-disciplinary approach drawing on clinical expertise and collaboration combined with community practice and cutting edge clinical and translational research. By optimizing partnerships through team medicine and clinical research, we combine our cancer center clinical expertise, community practice partnership, and clinical and translational research to understand the biology of this deadly disease, advance therapy and connect our patients with the optimal treatment that offers the best possible outcomes.

Use of HER2-Directed Therapy in Metastatic Breast Cancer and How Community Physicians Collaborate to Improve Care.

The development of new HER2-directed therapies has resulted in a significant prolongation of survival for women with metastatic HER2-positive breast cancer. Discoveries in the laboratory inform clinical trials which are the basis for improving the standard of care and are also the backbone for quality improvement. Clinical trials can be completed more rapidly by expanding trial enrollment to community sites. In this article we review some of the challenges in treating metastatic breast cancer with HER2-directed therapies and our strategies for incorporating our community partners into the research network.

Managing Bladder Cancer Care during the COVID-19 Pandemic Using a Team-Based Approach.

The recent novel coronavirus, named coronavirus disease 2019 (COVID-19), has developed into an international pandemic affecting millions of individuals with hundreds of thousands of deaths worldwide. The highly infectious nature and widespread prevalence of this disease create a new set of obstacles for the bladder cancer community in both delivering and receiving care. In this manuscript, we address the unique issues regarding treatment prioritization for the patient with bladder cancer and how we at City of Hope have adjusted our clinical practices using a team-based approach that utilizes shared decision making with all stakeholders (physicians, patients, caregivers) to optimize outcomes during this difficult time. In addition to taking standard precautions for minimizing COVID-19 risk of exposure for those entering a healthcare facility (screening all personnel upon entry and donning facemasks at all times), we suggest the following three measures: (1) delay post-treatment surveillance visits until there is a decrease in local COVID-19 cases, (2) continue curative intent treatments for localized bladder cancer with COVID-19 precautions (i.e., choosing gemcitabine/cisplatin (GC) over dose-dense methotrexate, vinblastine, doxorubicin, cisplatin (ddMVAC) neoadjuvant chemotherapy), and (3) increase the off-treatment period between cycles of palliative systemic therapy in metastatic urothelial carcinoma patients.

Dosing Three-Drug Combinations That Include Targeted Anti-Cancer Agents: Analysis of 37,763 Patients.

BACKGROUND: Combining targeted and cytotoxic agents has the potential to improve efficacy and attenuate resistance for metastatic cancer. Information regarding safe starting doses for clinical trials of novel three-drug combinations is lacking. MATERIALS AND METHODS: Published phase I-III adult oncology clinical trials of three-drug combinations involving a targeted agent were identified by PubMed search (January 1, 2010 to December 31, 2013). A dose percentage was calculated to compare the dose used in combination to the single agent recommended dose: (U.S. Food and Drug Administration-approved/recommended phase II dose/maximum tolerated dose). The additive dose percentage was the sum of the dose percentages for each drug in the combination. RESULTS: A total of 37,763 subjects and 243 drug combinations were included. Only 28% of studies could give each of the three agents at 100%. For combinations involving two targeted agents and a cytotoxic agent, the lowest starting additive dose percentage was 133%, which increased to 250% if two antibodies were included. For combinations of one targeted agent and two cytotoxic agents, the lowest additive safe dose percentage was 137%. When both cytotoxic agents were held at 100%, as occurred in 56% of studies (which generally used cytotoxic doublets with known combination safety dosing), the lowest safe dose percentage was 225% (providing that a histone deacetylase inhibitor was not the targeted agent). CONCLUSION: These findings serve as a safe starting point for dosing novel three-drug combinations involving a targeted agent in clinical trials and practice. The Oncologist 2017;22:576-584 IMPLICATIONS FOR PRACTICE: Targeted and cytotoxic drug combinations can improve efficacy and overcome resistance. More knowledge of safe starting doses would facilitate use of combinations in clinical trials and practice. Analysis of 37,763 subjects (243 combinations) showed three drugs could be safely administered, but less than 30% of combinations could include all three drugs at full dose. Dose reductions to 45% of the dose of each single agent may be required. Combinations involving two antibodies required fewer dose reductions, and the use of established cytotoxic doublets made initial dose assignment easier.

Dosing targeted and cytotoxic two-drug combinations: Lessons learned from analysis of 24,326 patients reported 2010 through 2013.

Combining agents has the potential to attenuate resistance in metastatic cancer. However, knowledge of appropriate starting doses for novel drug combinations in clinical trials and practice is lacking. Analysis of 372 published studies was used to ascertain safe starting doses for doublets involving a cytotoxic and targeted agent. Phase I-III adult oncology clinical trial publications (January 1, 2010 to December 31, 2013) were identified (PubMed). The dose of drug used in each combination was compared to the single agent recommended dose [FDA-approved/recommended phase 2 dose (RP2D)/maximum tolerated dose (MTD)]. Dose percentages were calculated as: (safe dose of drug in combination/dose of drug as single agent at FDA/RP2D/MTD) × 100. Additive dose percentages were the sum of the dose percentage for each drug. A total of 24,326 patients (248 drug combinations) were analyzed. In 38% of studies, both drugs could be administered at 100% of their FDA-approved/RP2D/MTD dose. The lowest safe additive dose percentage was 41% with poly-ADP ribose polymerase (PARP) or histone deacetylase inhibitors as the targeted agents; 82%, in the absence of these agents; and 97%, with an antibody in the combination. If one drug was administered at 100% of the single agent dose, the lowest safe dose percentage for the second drug was 17% (cytotoxic at 100%) or 36% (targeted at 100%) of the FDA-approved/RP2D/MTD dose. The current findings can help inform safe starting doses for novel two-drug combinations (cytotoxic and targeted agents) in the context of clinical trials and practice.

Dosing de novo combinations of two targeted drugs: Towards a customized precision medicine approach to advanced cancers.

Metastatic cancers harbor complex genomic alterations. Thus, monotherapies are often suboptimal. Individualized combinations are needed in order to attenuate resistance. To help inform selection of safe starting doses for novel, two-agent, targeted drug combinations, we identified clinical trials in adult oncology patients who received targeted drug doublets (PubMed, January 1, 2010 through December 31, 2013). The dose percentage was calculated for each drug: (safe dose in combination divided by single agent full dose) X 100. Additive dose percentage represented the sum of the dose percentage for each drug. A total of 144 studies (N = 8568 patients; 95 combinations) were analyzed. In 51% of trials, each of the two drugs could be administered at 100% of their full dose. The lowest safe additive dose percentage was 60% if targets and/or class of drugs overlapped, or in the presence of mTor inhibitors, which sometimes compromised the combination dose. If neither class nor target overlapped and if mTor inhibitors were absent, the lowest safe additive dose percentage was 143%. The current observations contribute to the knowledge base that informs safe starting doses for new combinations of targeted drugs in the context of clinical trials or practice, hence facilitating customized combination therapies.

Understanding Toxicities of Targeted Agents: Implications for Anti-tumor Activity and Management.

Targeted treatments have distinctive side effects: dermatologic problems (rash, hand-food skin reaction, skin/hair whitening), endocrine dysfunction (hyperglycemia, hypothyroidism, dyslipidemia), as well as hypertension, diarrhea, liver problems, ocular toxicity and proteinuria. Toxicities can be classified as: (1) on-target, mechanism-driven toxicities that are either related or unrelated to response; and (2) off-target side effects. Off-target toxicities may be specific to the class of agent, eg, small molecule tyrosine kinase inhibitor versus antibody versus cytotoxic; alternatively, they may also be mediated by metabolites or immune reactions. Both on- and off-target toxicities can be amplified or attenuated by drug concentrations or end-organ sensitivity, which in turn can be attributable to genetic polymorphisms regulating metabolism or tissue responsiveness. On-target side effects are important to identify as some are associated with response and, therefore, controlling these side effects is preferable to dose reduction or treatment discontinuation. Side effects caused by relevant target impact may be recognized when different types of agents, eg, small molecule inhibitors and antibodies, with the same target have the same side effect. These on-target effects may also correlate with better outcomes. We discuss toxicity of targeted agents in the context of understanding target impact, drug-drug interactions, and implications for optimized management.

Toxicity of targeted therapy: Implications for response and impact of genetic polymorphisms.

Targeted therapies have unique toxicity profiles. Common adverse events include rash, diarrhea, hypertension, hypothyroidism, proteinuria, depigmentation, and hepatotoxicity. Some of these toxicities are caused by on-target, mechanism-associated effects, which can be stratified as to whether or not the targets are relevant to response. Other toxicities are off-target and may be caused by the class of agent, e.g. antibody vs small molecule tyrosine kinase inhibitor, or by immune reactions or toxic metabolites. Both on- and off-target toxicities may be due to higher drug concentrations or altered end-organ sensitivity, which in turn can be a consequence of genetic polymorphisms controlling metabolism or tissue responsiveness. On-target toxicities are important to identify as some correlate with response and, hence, amelioration of these side effects is preferable to dose reduction or stopping drug. Toxicities secondary to relevant target impact may be recognized when distinct types of agents, such as antibodies and small molecule kinase inhibitors, with the same target have a similar side effect. For example, both bevacizumab and vascular endothelial growth factor receptor (VEGFR) kinase inhibitors cause hypertension; both epidermal growth factor receptor (EGFR) antibodies and kinase inhibitors cause rash; and these toxicities correlate with response. Herein we review common targeted agent-related toxicities, relevant genetic polymorphisms, and implications for response and patient management.