The field of oncology therapy has been undergoing significant changes in recent years. The latest data from IQVIA's white paper, Global Oncology Trends 2023 - outlook to 2027, shows that the number of PD-1/PD-L1 inhibitors, a hot R&D target in the oncology industry, is gradually decreasing and scientists are turning their attention to more innovative therapeutic strategies, such as next-generation antibody-drug conjugates (ADCs), bispecific antibodies and CAR-T cell therapies, etc., opening up a broader prospect for oncology treatment that can attack cancer cells with greater precision.
In 2022, 1,236 trials started globally testing PD-1/PD-L1 inhibitors. Although this is a significant increase compared to the 804 trials in 2017, it is still an 11% decrease compared to the number of trials initiated in 2021. IQVIA pointed out in the report that 2018 was a turning point in the development of PD-1/PD-L1 immune checkpoint inhibitors from "significant growth" to "gradual weakening", indicating a crowded market and a switch to even newer targeted molecules.
Figure 1. PD-1/PD-L1 inhibitor trials, source: reference 
PD-1/PD-L1 inhibitors are most commonly used in combination therapy in global trials, with more than 80% of clinical trials investigating their use in combination with other drugs targeting nearly 300 different targets and pathways.
In 2014, the US FDA approved the first PD-1/PD-L1 checkpoint inhibitor, Keytruda (Pembrolizumab), for use in patients with melanoma. Since then, seven additional PD-1/PD-L1 inhibitors have been approved for the treatment of a range of hematologic and solid tumors.
|Approved PD-1/PD-L1 inhibitors|
Table 1. FDA Approved PD-1/PD-L1 inhibitors
Although PD-1/PD-L1 inhibitors may be starting to lose favor among R&D teams, checkpoint inhibitors on the market continue to demonstrate their value. In 2022, global revenues from PD-1/PD-L1 immune checkpoint inhibitors are $41 billion, nearly half of which are associated with lung or kidney cancer. According to the revenue comparison of Keytruda, Opdivo, Tecentriq, and Imfinzi in recent years published by FirstWord PHARMA, it can be seen that sales of PD-1/PD-L1 inhibitor drugs are on the rise.
Figure 2. PD-1/PD-L1 inhibitors key brand revenues
Looking ahead, many PD-1/PD-L1 inhibitors are being used as combination therapies with other molecules as they are becoming the backbone of therapy for certain tumor types. This trend is expected to continue, as global spending on PD-1/PD-L1 inhibitors is expected to exceed $70 billion in 2027.
Antibody-Drug Conjugates (ADC)
Antibody-drug conjugate (ADC) has been widely studied for cancer treatment and consists of a monoclonal antibody combined with a cytotoxic drug that has significant efficacy against multiple targets.
In 2000, the first ADC, gemtuzumab ozogamicin (Mylotarg), received accelerated approval from FDA, but it was withdrawn in 2010 due to the presence of an unstable n-acylhydrazone linker causing severe hepatotoxicity. Mylotarg was re-approved in 2017 after re-engineering. Until now, 15 ADCs have been approved worldwide across 12 different targets and a range of hematologic and solid tumors.
|Drugs (Company)||Trade Names||Target antigens||Approved Countries||Approved Date||Approved Indications|
|Gemtuzumab ozogamicin (Pfizer)||Mylotarg®||CD33||FDA/EMA/PMDA||2000/5/17; 2017/9/1||AML|
|Brentuximab vedotin (Seagen)||Adcetris®||CD30||FDA/EMA/PMDA/NMPA||2011/8/19||Hodgkin lymphoma (HL); anaplastic large cell lymphoma (ALCL); pcALCL|
|Inotuzumab ozogamicin (Pfizer)||Besponsa®||CD22||FDA/EMA/PMDA/NMPA||2017/6/28||R/R Acute Lymphoblastic Leukemia|
|Moxetumomab pasudotox (AstraZeneca)||Lumoxiti®||CD22||FDA/EMA||2018/9/13||Hairy Cell Leukemia|
|Polatuzumab vedotin (Roche)||Polivy®||CD79B||FDA/EMA||2019/6/10||R/R DLBCL|
|Belantamab mafodotin (GSK)||Blenrep®||BCMA||EMA||2020/8/5||R/R MM (Withdrawn by FDA in 2022)|
|Loncastuximab tesirine (ADC Therapeutics)||Zynlonta®||CD19||FDA||2021/4/23||R/R large B-cell lymphoma|
|Ado-trastuzumab emtansine (Roche)||Kadcyla®||HER2||FDA/EMA/PMDA/NMPA||2013/2/22||HER2-positive early breast cancer|
|Enfortumab vedotin (Seagen)||Padcev®||Nectin-4||FDA||2019/12/18||locally advanced or metastatic urothelial cancer|
|Fam-trastuzumab deruxtecan (Daiichi Sankyo)||Enhertu®||HER2||FDA/EMA/PMDA||2019/12/20||Breast Cancer, Gastric Cancer, Non-Small Cell Lung Cancer|
|Sacituzumab govitecan (Immunomedics)||Trodelvy®||Trop-2||FDA/NMPA||2020/4/22||Breast Cancer, Urothelial Carcinoma|
|Cetuximab sarotalocan (Rakuten Medical)||Akalux®||EGFR||PMDA||2020/9/25||unresectable locally advanced or recurrent HNSCC|
|Disitamab vedotin (RemeGen)||Aidixi®||HER2||NMPA||2021/6/8||locally advanced or metastatic gastric cancer|
|Tisotumab vedotin (Genmab/Seagen)||Tivdak®||TF||FDA||2021/9/20||recurrent or metastatic cervical cancer|
|ELAHERE™||FRα||FDA||2022/11/14||epithelial ovarian, fallopian tube, or primary peritoneal cancer|
Table 2. Approved ADC worldwide
Despite some ADC research interruptions, 76 biomarker targets are still being investigated, among which the common solid tumor targets developed include 28 targeting HER2, 14 targeting CLDN18.2 and 12 targeting Trop-2.
Figure 3. ADCs under development by target, source: reference 
Significant progress has been made in ADC development, and future research will focus on new targets, different cytotoxic agents, different molecular structures, and different indications to improve the treatment of patients with conventional chemotherapy.
Bispecific antibodies (BsAb) can bind multiple targets and exert anti-tumor effects by bringing immune cells to cancer cells or by inhibiting or activating two separate targets. The FDA has approved seven bispecific antibodies for treating tumors, four for hematologic tumors, and three for solid tumors.
|FDA Approved Bispecific Antibodies|
|Drug Name||Trade Name||Company||Targets||First Approved Date (Country)||Indications|
|Blinatumomab||Blincyto||Amgen||CD3/CD19||Dec 2014||R/R precursor B-cell acute lymphoblastic leukemia(ALL)|
|Emicizumab||Hemlibra||Roche||FIXa/FX||Nov 2017||Bleeding due to hemophilia A|
|Amivantamab-vmjw||Rybrevant||Janssen||EGFR/cMet||May 2021||Non-small cell lung cancer|
|Tebentafusp-tebn||Kimmtrak||Immunocore||GP100/CD3||Jan 2022||unresectable or metastatic uveal melanoma|
|Faricimab-svoa||Vabysmo||Genentech||Ang-2/VEGF-A||Jan 2022||Wet AMD and DME|
|Mosunetuzumab||Lunsumio||Roche||CD20/CD3||Dec 2022||relapsed or refractory (R/R) follicular lymphoma (FL)|
|Epcoritamab||Epkinly||Genmab US||CD3/CD20||May 2023||DLBCL|
More than 130 bispecific antibodies are currently in development, of which 67% are for the treatment of solid tumors, 24% are for the treatment of hematologic systemic cancers, and nearly 9% are for both treatments. More than 50% of bispecific antibodies are in early clinical development, with only 7% of bispecific antibodies currently in Phase III clinical trials for hematologic tumors and 5% of bispecific antibodies in Phase III clinical trials for solid tumors.
Figure 4. Bispecific antibody pipeline by tumor and phase, source: reference 
Bispecific antibodies are being tested in a range of cancers, such as non-small cell lung cancer (NSCLC), multiple myeloma, non-Hodgkin's lymphoma (NHL) and esophageal cancer, where significant research advances have been made and many drugs are being developed for use in solid tumors. With the development of bispecific antibodies, new multispecific antibody paradigms are sprouting, such as trispecific antibodies.
CAR-T Cell Therapy
Chimeric antigen receptor (CAR) T-cell and natural killer (NK) cell therapies account for 74% of the next-generation biotherapeutic pipeline for hematologic cancers and are increasingly being investigated for solid tumors.
In 2017, the first CAR-T cell therapy, tisagenlecleucel, was approved for the treatment of acute lymphoblastic leukemia (ALL). Until now, a total of six CAR-T cell therapies are approved by FDA, including four for patients with B cell lymphomas, two for patients with B cell acute lymphoblastic leukaemia (B-ALL) and two for those with multiple myeloma (MM).
Figure 5. Approved CAR-T Cell therapies, reference 
In 2022, 264 trials investigating the use of CAR-T in oncology were initiated, with a 30% increase in solid tumor trial initiations and an 11% decrease in hematologic tumor trial initiations compared to 2021.
Of the 852 CAR-T trials underway in 2022, 72% of them are evaluating CAR-T in the treatment of hematologic tumors, with 343 of them focused on studies for the treatment of non-Hodgkin's lymphoma (NHL). In addition, trials of CAR-T for solid tumors account for 28% of ongoing trials, and research in solid tumors is gradually expanding across a range of difficult-to-treat cancers, such as gastric, ovarian, pancreatic, colorectal, and central nervous system cancers. While 98% of ongoing trials are in Phase I or Phase II, all CAR-T currently available in the U.S. are approved based on data from Phase I or Phase II trials.
Figure 6. Oncology CAR T-cell therapy clinical trials, source: reference 
Biopharma PEG provides GMP standard PEG derivatives and bulk orders via custom synthesis, offering the opportunity to match customers' special quality requirements. ADC linkers with molecular weights, branching, and functional groups not listed in our online catalog may be available by custom synthesis.
 Global Oncology Trends 2023 OUTLOOK TO 2027, https://www.iqvia.com/insights/the-iqvia-institute/reports/global-oncology-trends-2023
 Cappell, K.M., Kochenderfer, J.N. Long-term outcomes following CAR T cell therapy: what we know so far. Nat Rev Clin Oncol 20, 359–371 (2023). https://doi.org/10.1038/s41571-023-00754-1
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