Combination therapy or polytherapy is therapy that uses more than one medication or modality. Typically, the term refers to using multiple therapies to treat a single disease, and often all the therapies are pharmaceutical (although it can also involve non-medical therapy, such as the combination of medications and talk therapy to treat depression). 'Pharmaceutical' combination therapy may be achieved by prescribing/administering separate drugs, or, where available, dosage forms that contain more than one active ingredient (such as fixed-dose combinations).
Polypharmacy is a related term, referring to the use of multiple medications (without regard to whether they are for the same or separate conditions/diseases). Sometimes "polymedicine" is used to refer to pharmaceutical combination therapy. Most of these kinds of terms lack a universally consistent definition, so caution and clarification are often advisable.
Conditions treated with combination therapy include tuberculosis, leprosy, cancer, malaria, and HIV/AIDS. One major benefit of combination therapies is that they reduce development of drug resistance since a pathogen or tumor is less likely to have resistance to multiple drugs simultaneously. Artemisinin-based monotherapies for malaria are explicitly discouraged to avoid the problem of developing resistance to the newer treatment.
Combination therapy may seem costlier than monotherapy in the short term, but when it is used appropriately, it causes significant savings: lower treatment failure rate, lower case-fatality ratios, fewer side-effects than monotherapy, slower development of resistance, and thus less money needed for the development of new drugs. [1]
Combination therapy has gained momentum in oncology in recent years, with various studies demonstrating higher response rates with combinations of drugs compared to monotherapies, [2] [3] and the FDA recently approving therapeutic combination regimens that demonstrated superior safety and efficacy to monotherapies. [4] In a recent study about solid cancers, Martin Nowak, Bert Vogelstein, and colleagues showed that in most clinical cases, combination therapies are needed to avoid the evolution of resistance to targeted drugs. Furthermore, they find that the simultaneous administration of multiple targeted drugs minimizes the chance of relapse when no single mutation confers cross-resistance to both drugs. [1]
Various systems biology methods must be used to discover combination therapies to overcome drug resistance in select cancer types. [5] [6] Recent precision medicine approaches have focused on targeting multiple biomarkers found in individual tumors by using combinations of drugs. [7] [8] However, with 300 FDA-approved cancer drugs on the market, there almost 45,000 possible two-drug combinations and almost 4.5 million three-drug combinations for to choose from. [9] That level of complexity is one of the primary impediments to the growth of combination therapy in oncology. [7]
The National Cancer Institute has recently highlighted combination therapy as a top research priority in oncology. [10]
Combination therapy with two or more antibiotics are often used in an effort to treat multi-drug resistant Gram-negative bacteria. [11]
Monotherapy, or the use of a single therapy, can be applied to any therapeutic approach, but it is most commonly used to describe the use of a single medication. Normally, monotherapy is selected because a single medication is adequate to treat the medical condition. However, monotherapies may also be used because of unwanted side effects or dangerous drug interactions. [12]
In biology, chimeric antigen receptors (CARs)—also known as chimeric immunoreceptors, chimeric T cell receptors or artificial T cell receptors—are receptor proteins that have been engineered to give T cells the new ability to target a specific antigen. The receptors are chimeric in that they combine both antigen-binding and T cell activating functions into a single receptor.
Cancer immunotherapy (immuno-oncotherapy) is the stimulation of the immune system to treat cancer, improving the immune system's natural ability to fight the disease. It is an application of the fundamental research of cancer immunology and a growing subspecialty of oncology.
Dasatinib, sold under the brand name Sprycel among others, is a targeted therapy medication used to treat certain cases of chronic myelogenous leukemia (CML) and acute lymphoblastic leukemia (ALL). Specifically it is used to treat cases that are Philadelphia chromosome-positive (Ph+). It is taken by mouth.
Ipilimumab, sold under the brand name Yervoy, is a monoclonal antibody medication that works to activate the immune system by targeting CTLA-4, a protein receptor that downregulates the immune system.
Pazopanib, sold under the brand name Votrient, is an anti-cancer medication marketed worldwide by Novartis. It is a potent and selective multi-targeted receptor tyrosine kinase inhibitor that blocks tumour growth and inhibits angiogenesis. It has been approved for renal cell carcinoma and soft tissue sarcoma by numerous regulatory administrations worldwide.
PARP inhibitors are a group of pharmacological inhibitors of the enzyme poly ADP ribose polymerase (PARP).
A CDK inhibitor is any chemical that inhibits the function of CDKs. They are used to treat cancers by preventing overproliferation of cancer cells. The US FDA approved the first drug of this type, palbociclib (Ibrance), a CDK4/6 inhibitor, in February 2015, for use in postmenopausal women with breast cancer that is estrogen receptor positive and HER2 negative. While there are multiple cyclin/CDK complexes regulating the cell cycle, CDK inhibitors targeting CDK4/6 have been the most successful, with 4 CDK4/6 inhibitors haven been FDA approved. No inhibitors targeting other CDKs have been FDA approved, but several compounds are in clinical trials.
ALK inhibitors are anti-cancer drugs that act on tumours with variations of anaplastic lymphoma kinase (ALK) such as an EML4-ALK translocation. They fall under the category of tyrosine kinase inhibitors, which work by inhibiting proteins involved in the abnormal growth of tumour cells. All the current approved ALK inhibitors function by binding to the ATP pocket of the abnormal ALK protein, blocking its access to energy and deactivating it. A majority of ALK-rearranged NSCLC harbour the EML4-ALK fusion, although as of 2020, over 92 fusion partners have been discovered in ALK+ NSCLC. For each fusion partner, there can be several fusion variants depending on the position the two genes were fused at, and this may have implications on the response of the tumour and prognosis of the patient.
Temozolomide, sold under the brand name Temodar among others, is an anticancer medication used to treat brain tumors such as glioblastoma and anaplastic astrocytoma. It is taken by mouth or via intravenous infusion.
Daratumumab, sold under the brand name Darzalex, is an anti-cancer monoclonal antibody medication. It binds to CD38, which is overexpressed in multiple myeloma cells. Daratumumab was originally developed by Genmab, but it is now being jointly developed by Genmab along with the Johnson & Johnson subsidiary Janssen Biotech, which acquired worldwide commercialization rights to the drug from Genmab.
A MEK inhibitor is a chemical or drug that inhibits the mitogen-activated protein kinase kinase enzymes MEK1 and/or MEK2. They can be used to affect the MAPK/ERK pathway which is often overactive in some cancers.
Pembrolizumab, sold under the brand name Keytruda, is a humanized antibody used in cancer immunotherapy that treats melanoma, lung cancer, head and neck cancer, Hodgkin lymphoma, stomach cancer, cervical cancer, and certain types of breast cancer. It is administered by slow intravenous injection.
Palbociclib, sold under the brand name Ibrance among others, is a medication developed by Pfizer for the treatment of HR-positive and HER2-negative breast cancer. It is a selective inhibitor of the cyclin-dependent kinases CDK4 and CDK6. Palbociclib was the first CDK4/6 inhibitor to be approved as a cancer therapy.
Ceritinib is a prescription-only drug used for the treatment of non-small cell lung cancer (NSCLC). It was developed by Novartis and received FDA approval for use in April 2014..Ceritinib is also sold under the brand name Spexib in few countries by Novartis.
Isatuximab, sold under the brand name Sarclisa, is a monoclonal antibody (mAb) medication for the treatment of multiple myeloma.
Apalutamide, sold under the brand name Erleada among others, is a nonsteroidal antiandrogen (NSAA) medication which is used in the treatment of prostate cancer. It is specifically indicated for use in conjunction with castration in the treatment of non-metastatic castration-resistant prostate cancer (NM-CRPC). It is taken by mouth.
Osimertinib, sold under the brand name Tagrisso, is a medication used to treat non-small-cell lung carcinomas with specific mutations. It is a third-generation epidermal growth factor receptor tyrosine kinase inhibitor.
Crizanlizumab, sold under the brand name Adakveo among others, is a monoclonal antibody medication that binds to P-selectin. It is a medication used to reduce the frequency of vaso-occlusive crisis in people aged 16 years and older who have sickle cell anemia. It is given by injection into a vein.
Checkpoint inhibitor therapy is a form of cancer immunotherapy. The therapy targets immune checkpoints, key regulators of the immune system that when stimulated can dampen the immune response to an immunologic stimulus. Some cancers can protect themselves from attack by stimulating immune checkpoint targets. Checkpoint therapy can block inhibitory checkpoints, restoring immune system function. The first anti-cancer drug targeting an immune checkpoint was ipilimumab, a CTLA4 blocker approved in the United States in 2011.
Phenotypic response surfaces (PRS) is an artificial intelligence-guided personalized medicine platform that relies on combinatorial optimization principles to quantify drug interactions and efficacies to develop optimized combination therapies to treat a broad spectrum of illnesses.
Monotherapy: The treatment of epilepsy with a single medication rather than a combination. Monotherapy has advantages over combining medications in many patients, including absence of drug-drug interactions, fewer side effects, simpler dosing, and lower cost. However, not all patients can be controlled with monotherapy.