Understanding Monoclonal Antibodies
Monoclonal antibodies (mAbs) are laboratory-produced proteins designed to function like the natural antibodies your immune system creates [1.8.1]. Their power lies in their specificity; each mAb is engineered to recognize and bind to one particular protein, known as an antigen [1.8.2]. These antigens are often found on the surface of unhealthy cells, like cancer cells, or are molecules that drive disease processes [1.8.1]. By targeting these specific molecules, mAbs can offer a precise form of treatment, often with fewer side effects than traditional therapies like chemotherapy [1.9.1, 1.9.5].
There are several types of monoclonal antibodies used in medicine [1.8.1, 1.8.2]:
- Naked mAbs: These are the most common type and work by themselves. They can mark cancer cells for destruction by the immune system, block signals that cause cancer cells to grow, or interfere with tumor blood vessel growth [1.8.1, 1.9.5].
- Conjugated mAbs: These antibodies are joined to another molecule, such as a chemotherapy drug or a radioactive particle. They act as a delivery system, carrying the toxic agent directly to the target cells, which minimizes damage to healthy cells. These are often called Antibody-Drug Conjugates (ADCs) [1.8.1, 1.2.2].
- Bispecific mAbs: A newer innovation, these antibodies are engineered to attach to two different proteins at the same time. For instance, a bispecific mAb might bind to a cancer cell with one arm and an immune cell with the other, bringing them together to enhance the immune attack [1.8.2].
A New Wave of Approvals in 2024-2025
The field of pharmacology is seeing a surge of new monoclonal antibody approvals, offering hope for patients with a variety of conditions. Recent approvals and promising candidates in 2024 and 2025 highlight significant progress, particularly in oncology and inflammatory diseases.
Antibody-Drug Conjugates (ADCs) for Cancer
ADCs are often described as a "magic bullet" for their ability to deliver potent chemotherapy directly to cancer cells [1.2.2]. Several new ADCs have recently been approved or are nearing approval.
- Datopotamab Deruxtecan (Datroway): Jointly developed by AstraZeneca and Daiichi Sankyo, this ADC was approved by the FDA in January 2025 for adult patients with a type of non-small cell lung cancer (NSCLC) who have received prior therapy [1.2.2]. It targets a protein called TROP2, which is highly expressed on many solid tumors but not on normal tissue. In clinical trials, it showed a significant improvement in progression-free survival compared to standard chemotherapy [1.2.2].
- Telisotuzumab Vedotin (Emrelis): The FDA granted accelerated approval to this ADC from AbbVie in May 2025 for adults with advanced NSCLC whose tumors have high levels of c-Met protein overexpression [1.2.2]. It is the first c-Met directed ADC to enter Phase III trials and showed a notable response rate in patients with this specific tumor characteristic [1.2.2].
Innovations in Respiratory and Inflammatory Diseases
Monoclonal antibodies are also changing how chronic inflammatory conditions are managed.
- Depemokimab: This investigational mAb from GSK is poised to be the first ultra-long-acting biologic for severe asthma, with a proposed dosing schedule of just two injections per year [1.4.1, 1.4.2]. It targets interleukin-5 (IL-5), a key driver of type 2 inflammation which is present in over 80% of severe asthma patients [1.4.2]. The FDA has accepted its application for review for both severe asthma and chronic rhinosinusitis with nasal polyps, with a decision date set for December 16, 2025 [1.4.1, 1.4.5].
- Nirsevimab (Beyfortus): While approved in 2023, this long-acting mAb for preventing Respiratory Syncytial Virus (RSV) in infants has been a major focus through the 2024-2025 RSV season. RSV is the leading cause of hospitalization for infants in the U.S. [1.5.1]. Early real-world data from 2024 shows that nirsevimab is highly effective—around 90%—at preventing RSV-associated hospitalization in infants during their first season [1.5.2].
Advancements in Other Areas
The application of mAbs extends to rare diseases and neurodegenerative disorders.
- Crovalimab (Piasky): This novel C5 inhibitor was approved in China and Japan in 2024 for the treatment of Paroxysmal Nocturnal Hemoglobinuria (PNH), a rare, life-threatening blood disorder [1.6.3]. It works by blocking a part of the immune system called the complement system, which mistakenly destroys red blood cells in PNH patients [1.6.1]. Its key advantage is that it can be administered via a subcutaneous injection just once every four weeks, a significant improvement in convenience over older IV therapies [1.6.5]. It is currently under review in the U.S. and Europe [1.6.3].
- Lecanemab (Leqembi): Granted full FDA approval in July 2023, lecanemab is a significant, albeit controversial, new treatment for early Alzheimer's disease [1.3.1]. It is an antibody that targets and removes amyloid-beta plaques from the brain, which are a hallmark of the disease [1.3.6]. While it has shown a modest slowing of cognitive decline, it also carries risks, most notably amyloid-related imaging abnormalities (ARIA), which involve brain swelling or bleeding [1.3.1, 1.3.4].
Comparison of New Monoclonal Antibodies
| Drug Name (Brand Name) | Target | Primary Indication(s) | Administration / Dosing Schedule |
|---|---|---|---|
| Datopotamab Deruxtecan (Datroway) | TROP2 | Non-Small Cell Lung Cancer (NSCLC) [1.2.2] | Intravenous (IV) Infusion [1.2.2] |
| Depemokimab | Interleukin-5 (IL-5) | Severe Asthma, CRSwNP (Pending) [1.4.1] | Subcutaneous injection every 6 months [1.4.1] |
| Crovalimab (Piasky) | Complement C5 | Paroxysmal Nocturnal Hemoglobinuria (PNH) [1.6.3] | Subcutaneous injection every 4 weeks [1.6.5] |
The Broader Picture: Benefits and Risks
The primary benefit of monoclonal antibody therapy is its targeted nature, which allows it to attack diseased cells or pathways while largely sparing healthy tissues [1.9.1]. This often results in fewer severe side effects compared to traditional chemotherapy [1.9.5]. These drugs can be highly effective, leading to significant improvements in outcomes for cancers and other serious diseases [1.9.2].
However, these therapies are not without risks. Common side effects include infusion-related reactions, which can present as flu-like symptoms, fever, rashes, and headaches [1.8.2]. More serious side effects can occur and are often related to the antibody's specific target. For example, bevacizumab, which blocks blood vessel growth, can cause high blood pressure and bleeding [1.9.5]. Lecanemab's effect on amyloid in brain blood vessels can lead to ARIA [1.3.1]. Other limitations include the high cost of treatment and the potential for diseases to develop resistance over time [1.9.1].
Conclusion: The Future of Targeted Medicine
The rapid development and approval of new monoclonal antibodies in 2024 and 2025 underscore a major shift in medicine toward highly specific, targeted treatments. From ultra-long-acting injections for asthma to precisely delivered cancer drugs, these therapies are transforming patient care across a spectrum of diseases. As research continues, the focus will be on identifying new targets, minimizing side effects, and making these revolutionary treatments more accessible to the patients who need them.
For more information on investigational antibody therapies, see this page from the National Cancer Institute.
