Cancer care in 2017: the promise of more cures with the challenges of an unstable health care system

Diagnostics

The concept of personalized medicine is based on identifying biomarkers that are predictive of a patient’s response to treatment. There has been much progress toward applying NGS of tumors for use in the clinic, but we are still awaiting evidence from randomized clinical trials that such approaches prolong overall or progression-free survival.¹² Dr Julie Lange, an associate professor of clinical surgery and director of the Breast Cancer Program at the Keck School of Medicine at the University of Southern California, Los Angeles, provided me with the references to key studies in this field in which she is a leading researcher.¹³ However, she pointed out that in the absence of effective therapies, advanced biomarker testing may be less helpful, as is the case in heavily pretreated patients,¹⁴ unless a molecular test can pinpoint a potentially clinically actionable mutation. With the plethora of available assays and the high costs of molecular testing, clinicians are challenged in knowing what testing is best for which patients. Findings from a number of key ongoing national trials may eventually help us understand which tumor mutations in which tumor types can be most effectively targeted when multiple targetable mutations are found (TAPUR,¹⁵ MATCH,¹⁶ and QUILT¹⁷ and other basket trials¹⁸). The complexity of molecular testing has led to the development of institutional, trial-based, or co-operative group molecular tumor boards to provide guidance on specific targeted therapies for specific tumor mutations.

ASCO has launched a monthly series called Molecular Oncology Tumor Boards¹⁹ to expand the knowledge base in this field. It is presented as user-driven discussions designed to help providers integrate the use of the new genetic and genomic tests and their results into the day-to-day clinical care of patients with cancer.²⁰

Liquid biopsies

As busy clinicians, we need to understand the differences in liquid biopsy tests and their correlation with actionable targets, especially given the rapid progress in this field. Again, Dr Lange offered clarity on those differences. Liquid biopsy, refers to using a blood draw to isolate circulating tumor cells (CTCs) or circulating tumor DNA (ctDNA) to assess tumor biomarkers.²¹ Both CTCs and ctDNA tests have been shown to be prognostic of worse survival.^22-24 Liquid biopsies are currently supplemental to direct tumor biopsies, not replacements for them. The theoretical advantage of liquid biopsies is that they may reflect tumor heterogeneity by examining the repertoire of mutations contributed by diverse metastatic sites that shed CTCs or ctDNA into the circulation. The question is which type of testing can best inform therapy decisions.

Assays for ctDNA using droplet digital PCR [polymerase chain reaction], a digital PCR method based on water-oil emulsion droplet technology, require a priori knowledge of the specific mutation associated with response or lack of response to a specific therapy.^25,26 Technical issues related to the detection of rare alleles present within a mixed population of leukocytes, and ctDNA remains a challenge for many ctDNA assays. However, there is evidence to suggest that whole-exome sequencing of ctDNA is concordant with mutations in metastases,²⁷ however benchmarking ctDNA against tissue biopsies of metastases was not possible in all studies because tumor blocks were not available or because of the failure of tumor NGS assays. ^28,29

Newer generations of CTC assays take advantage of the circulating tumor cell as a functional assay for mutational status, gene expression, proteomics, epigenetics, and/or chemosensitivity of cultured cells. The relationship between CTCs and ctDNA remains uncertain as to whether CTCs are the cell of origin for ctDNA or if ctDNA may reflect responding or resistant tumor populations. The use of NGS on tumor specimens, ctDNA, and CTCs as a discovery tool is advancing the field by improving the understanding of disease heterogeneity and potential treatment targets. These results require correlation with patterns of response to therapy, and ultimately require validation in randomized clinical trials to provide strong evidence justifying their use outside of clinical trials. We can look forward to a time in the not distant future when specific liquid biopsy assays will reflect the array of mutations in different metastatic sites with validation that they correlate with efficacy of targeting those mutations that have targetable therapies.

From the FDA

New approvals

• Trastuzumab-dkst (Ogivri, Mylan; Dec 1) was approved as a biosimilar to trastuzumab (Herceptin, Genentech) for the treatment of patients with HER2-overexpressing breast or metastatic stomach cancer (gastric or gastroesophageal junction adenocarcinoma).
• Sunitinib malate (Sutent, Pfizer; Nov 16) was approved for the adjuvant treatment of adult patients at high risk of recurrent renal cell carcinoma after nephrectomy.
• Obinutuzumab (Gazyva, Genentech; Nov 16) received regular approval in combination with chemotherapy, followed by obinutuzumab monotherapy in patients achieving partial remission, for adult patients with previously untreated stage II bulky, III, or IV follicular lymphoma.
• Emicizumab-kxwh (Hemlibra, Genentech; Nov 16) was approved for routine prophylaxis to prevent or reduce the frequency of bleeding episodes in adult and pediatric patients with hemophilia A with factor VIII inhibitors.
• Dasatinib (Sprycel, Bristol-Myers Squibb; Nov 9) was approved for the treatment of pediatric patients with Philadelphia chromosome-positive chronic myeloid leukemia (CML) in the chronic phase.
• Brentuximab vedotin (Adcetris, Seattle Genetics; Nov 9) for the treatment of previously treated adult patients with primary cutaneous anaplastic large cell lymphoma (pcALCL) or CD30-expressing mycosis fungoides.
• Alectinib (Alecensa, Hoffmann-La Roche/Genentech; Nov 6) was approved for treatment of patients with anaplastic lymphoma kinase–positive metastatic non-small cell lung cancer (NSCLC), as detected by an FDA-approved test.
• Vemurafenib (Zelboraf, Hoffmann-La Roche; Nov 6) received approval for the treatment of Acalabrutinib (Calquence, AstraZeneca/Acerta; Oct 31) was granted accelerated approval for treatment of adult patients with mantle cell lymphoma (MCL) who have received at least one previous therapy.
• Axicabtagene ciloleucel (Yescarta, Kite; Oct 18), a CART therapy, was approved for treatment of adult patients with relapsed or refractory large B-cell lymphoma after two or more lines of systemic therapy, including diffuse large B-cell lymphoma (DLBCL) not otherwise specified, primary mediastinal large B-cell lymphoma, high-grade B-cell lymphoma, and DLBCL arising from follicular lymphoma. The complete remission rate reviewed by the FDA for trial patients was 51%.³⁰ It was the second CART therapy this year to receive approval (see tisagenlecleucel; Aug 30). The agency granted orphan drug designation and priority review to therapy for this indication.
• Abemaciclib (Verzenio, Eli Lilly; Sep 28) was approved in combination with fulvestrant for women with hormone receptor-positive, HER2-negative advanced or metastatic breast cancer with disease progression following endocrine therapy.
• Copanlisib (Aliqopa, Bayer; Sep 14) got accelerated approval for the treatment of adult patients with relapsed follicular lymphoma who have received at least two prior systemic therapies.
• Bevacizumab-awwb (Mvasi, Amgen; Sep 14) was approved as a biosimilar to bevacizumab (Avastin, Genentech) for treating multiple types of cancer. It was the first biosimilar approved in the US for the treatment of cancer.
• Gemtuzumab ozogamicin (Mylotarg, Pfizer; Sep 1) was approved for the treatment of newly diagnosed CD33-positive acute myeloid leukemia (AML) in adults and of relapsed/refractory CD33-positive AML in adults and pediatric patients aged 2 or older. It can be used in combination with daunorubicin and cytarabine for adults with newly diagnosed AML, or as a standalone treatment for certain adult and pediatric patients. The drug was originally approved in 2000 as a standalone treatment for CD33-positive AML in patients older than 60 years, but was withdrawn in 2010 because of safety concerns and postmarketing trials could not confirm benefit. The current approval is for a lower recommended dose and schedule.³¹
• Tisagenlecleucel (Kymriah, Novartis; Aug 30) was approved for the treatment of patients up to age 25 years with B-cell precursor acute lymphoblastic leukemia (ALL) that is refractory or in second or later relapse. It is the first CART immunotherapy approved by the agency.
• Inotuzumab ozogamicin (Besponsa, Wyeth; Aug 17) was approved for the treatment of adults with relapsed or refractory B-cell precursor ALL.
• A liposome-encapsulated combination of daunorubicin and cytarabine (Vyxeos, Jazz; Aug 3) was approved for the treatment of adults with newly diagnosed therapy-related AML (t-AML) or AML with myelodysplasia-related changes (AML-MRC), two types of AML having a poor prognosis.
• Enasidenib (Idhifa, Celgene; Aug 1) was approved for the treatment of adult patients with relapsed or refractory AML with an isocitrate dehydrogenase-2 mutation as detected by an FDA-approved test.
• Neratinib (Nerlynx, Puma; Jul 17) was approved as the first extended adjuvant therapy for adult patients with early stage HER2-overexpressed/amplified breast cancer, to follow adjuvant trastuzumab-based therapy.
• Blinatumomab (Blincyto, Amgen; Jul 11) was approved for the treatment of relapsed or refractory B-cell precursor acute lymphoblastic leukemia in adults and children.
• L-glutamine oral powder (Endari, Emmaus; Jul 7) was approved for oral administration to reduce the acute complications of sickle cell disease in adult and pediatric patients 5 years and older.
• Betrixaban (Bevyxxa, Portola; Jun 23) was approved for the prophylaxis of venous thromboembolism (VTE) in adult patients hospitalized for an acute medical illness who are at risk for thromboembolic complications because of moderate or severe restricted mobility and other risk factors for VTE.
• The combination of rituximab and hyaluronidase human (Rituxan Hycela, Genentech; Jun 22) was approved for adult patients with follicular lymphoma, DLBCL, and chronic lymphocytic leukemia. Hyaluronidase human is an enzyme that helps deliver the rituximab. This formulation allows subcutaneous administration of the combination, which will shorten patient visit times and potentially even allow at-home therapy delivery.
• Ceritinib (Zykadia, Novartis; May 26) was approved for patients with metastatic NSCLC whose tumors are anaplastic lymphoma kinase (ALK)-positive as detected by an FDA-approved test.
• Avelumab (Bavencio, EMD Serono; May 9) got accelerated approval for patients with locally advanced or metastatic urothelial carcinoma whose disease progressed during or following platinum-containing chemotherapy or within 12 months of neoadjuvant or adjuvant platinum-containing chemotherapy.
• Durvalumab (ImfinzI, AstraZeneca; May 1) got accelerated approval for the treatment of patients with locally advanced or metastatic urothelial carcinoma who have disease progression during or following platinum-containing chemotherapy or who have disease progression within 12 months of neoadjuvant or adjuvant treatment with platinum-containing chemotherapy.
• Brigatinib (Alunbrig tablets, Takeda through Ariad; Apr 28) got accelerated approval for the treatment of patients with metastatic anaplastic lymphoma kinase (ALK)-positive NSCLC who have progressed on or are intolerant to crizotinib.
• Midostaurin (Rydapt, Novartis; Apr 28) was approved for the treatment of adult patients with newly diagnosed AML who are FLT3 mutation-positive, as detected by an FDA-approved test, in combination with standard cytarabine and daunorubicin induction and cytarabine consolidation.
• Osimertinib (Tagrisso, AstraZeneca; Mar 30) got regular approval for the treatment of patients with metastatic epidermal growth factor receptor (EGFR) T790M mutation-positive NSCLC, as detected by an FDA-approved test, whose disease has progressed on or after EGFR tyrosine-kinase inhibitor therapy.
• Niraparib (Zejula, Tesaro; Mar 27), a poly ADP-ribose polymerase (PARP) inhibitor, was approved for the maintenance treatment of adult patients with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in complete or partial response to platinum-based chemotherapy.
• Avelumab (Mar 23), a PD-L1–blocking human IgG1 lambda monoclonal antibody, got accelerated approval for the treatment of patients 12 years and older with metastatic Merkel cell carcinoma. It is the first FDA-approved product to treat this type of cancer.
• Ribociclib (Kisqali, Novartis; Mar 13), a CDK4/6 inhibitor, was approved as a breakthrough therapy after priority review for use in combination with an aromatase inhibitor as initial endocrine-based therapy for the treatment of postmenopausal women with HR-positive, HER2-negative advanced or metastatic breast cancer.