For the past 10 years, the annual 'Antibodies to watch' articles have provided updates on key events in the late-stage development of antibody therapeutics, such as first regulatory review or approval, that occurred in the year before publication or were anticipated to occur during the year of publication. To commemorate the 10th anniversary of the article series and to celebrate the 2018 Nobel Prizes in Chemistry and in Physiology or Medicine, which were given for work that is highly relevant to antibody therapeutics research and development, we expanded the scope of the data presented to include an overview of all commercial clinical development of antibody therapeutics and approval success rates for this class of molecules. Our data indicate that: 1) antibody therapeutics are entering clinical study, and being approved, in record numbers; 2) the commercial pipeline is robust, with over 570 antibody therapeutics at various clinical phases, including 62 in late-stage clinical studies; and 3) Phase 1 to approval success rates are favorable, ranging from 17-25%, depending on the therapeutic area (cancer vs. non-cancer). In 2018, a record number (12) of antibodies (erenumab (Aimovig), fremanezumab (Ajovy), galcanezumab (Emgality), burosumab (Crysvita), lanadelumab (Takhzyro), caplacizumab (Cablivi), mogamulizumab (Poteligeo), moxetumomab pasudodox (Lumoxiti), cemiplimab (Libtayo), ibalizumab (Trogarzo), tildrakizumab (Ilumetri, Ilumya), emapalumab (Gamifant)) that treat a wide variety of diseases were granted a first approval in either the European Union (EU) or United States (US). As of November 2018, 4 antibody therapeutics (sacituzumab govitecan, ravulizumab, risankizumab, romosozumab) were being considered for their first marketing approval in the EU or US, and an additional 3 antibody therapeutics developed by Chinese companies (tislelizumab, sintilimab, camrelizumab) were in regulatory review in China. In addition, our data show that 3 product candidates (leronlimab, brolucizumab, polatuzumab vedotin) may enter regulatory review by the end of 2018, and at least 12 (eptinezumab, teprotumumab, crizanlizumab, satralizumab, tanezumab, isatuximab, spartalizumab, MOR208, oportuzumab monatox, TSR-042, enfortumab vedotin, ublituximab) may enter regulatory review in 2019. Finally, we found that approximately half (18 of 33) of the late-stage pipeline of antibody therapeutics for cancer are immune checkpoint modulators or antibody-drug conjugates. Of these, 7 (tremelimumab, spartalizumab, BCD-100, omburtamab, mirvetuximab soravtansine, trastuzumab duocarmazine, and depatuxizumab mafodotin) are being evaluated in clinical studies with primary completion dates in late 2018 and in 2019, and are thus 'antibodies to watch'. We look forward to documenting progress made with these and other 'antibodies to watch' in the next installment of this article series.

This 2020 installment of the annual 'Antibodies to Watch' series documents the antibody therapeutics approved in 2019 and in regulatory review in the United States or European Union, as well as those in late-stage clinical studies, as of November 2019*. At this time, a total of 5 novel antibody therapeutics (romosozumab, risankizumab, polatuzumab vedotin, brolucizumab, and crizanlizumab) had been granted a first approval in either the US or EU, and marketing applications for 13 novel antibody therapeutics (eptinezumab, teprotumumab, enfortumab vedotin, isatuximab, [fam-]trastuzumab deruxtecan, inebilizumab, leronlimab, sacituzumab govitecan, satralizumab, narsoplimab, tafasitamab, REGNEB3 and naxituximab) were undergoing review in these regions, which represent the major markets for antibody therapeutics. Also as of November 2019, 79 novel antibodies were undergoing evaluation in late-stage clinical studies. Of the 79 antibodies, 39 were undergoing evaluation in late-stage studies for non-cancer indications, with 2 of these (ublituximab, pamrevlumab) also in late-stage studies for cancer indications. Companies developing 7 (tanezumab, aducanumab, evinacumab, etrolizumab, sutimlimab, anifrolumab, and teplizumab) of the 39 drugs have indicated that they may submit a marketing application in either the US or EU in 2020. Of the 79 antibodies in late-stage studies, 40 were undergoing evaluation as treatments for cancer, and potentially 9 of these (belantamab mafodotin, oportuzumab monatox, margetuximab, dostarlimab, spartalizumab, 131I-omburtamab, loncastuximab tesirine, balstilimab, and zalifrelimab) may enter regulatory review in late 2019 or in 2020. Overall, the biopharmaceutical industry's clinical pipeline of antibody therapeutics is robust, and should provide a continuous supply of innovative products for patients in the future. *Note on key updates through December 18, 2019: 1) the US Food and Drug Administration granted accelerated approval to enfortumab vedotin-ejfv (Padcev) on December 18, 2019, bringing the total number of novel antibody therapeutics granted a first approval in either the US or EU during 2019 to 6; 2) the European Commission approved romosozumab on December 9, 2019; 3) the European Medicines Agency issued a positive opinion for brolucizumab; 4) Sesen Bio initiated a rolling biologics license application (BLA) on December 6, 2019; 5) GlaxoSmithKline submitted a BLA for belantamab mafodotin; and 6) the status of the Phase 3 study (NCT04128696) of GSK3359609, a humanized IgG4 anti-ICOS antibody, in patients with head and neck squamous cell carcinoma was updated to recruiting from not yet recruiting. ARTICLE HISTORY

The characterization of the microenvironment of human tumors led to the description of tertiary lymphoid structures (TLS) characterized by mature dendritic cells in a T-cell zone adjacent to B-cell follicle including a germinal center. TLS represent sites of lymphoid neogenesis that develop in most solid cancers. Analysis of the current literature shows that the TLS presence is associated with a favorable clinical outcome for cancer patients, regardless of the approach used to quantify TLS and the stage of the disease. Using several approaches that combine immunohistochemistry, gene expression assays, and flow cytometry on large series of lung tumors, our work demonstrated that TLS are important sites for the initiation and/or maintenance of the local and systemic T- and B-cell responses against tumors. Surrounded by high endothelial venules, they represent a privileged area for the recruitment of lymphocytes into tumors and generation of central-memory T and B cells that circulate and limit cancer progression. TLS can be considered as a novel biomarker to stratify the overall survival risk of untreated cancer patients and as a marker of efficient immunotherapies. The induction and manipulation of cancer-associated TLS using drug agonists and/or biotherapies should open new avenues to treat cancer patients.

Tertiary lymphoid structures (TLS) are ectopic lymphoid aggregates that reflect lymphoid neogenesis occurring in tissues at sites of inflammation. They are detected in tumors where they orchestrate local and systemic anti-tumor responses. A correlation has been found between high densities of TLS and prolonged patient’s survival in more than 10 different types of cancer. TLS can be regulated by the same set of chemokines and cytokines that orchestrate lymphoid organogenesis and by regulatory T cells. Thus, TLS offer a series of putative new targets that could be used to develop therapies aiming to increase the anti-tumor immune response.

In this 12 th annual installment of the Antibodies to Watch article series, we discuss key events in antibody therapeutics development that occurred in 2020 and forecast events that might occur in 2021. The coronavirus disease 2019 (COVID-19) pandemic posed an array of challenges and opportunities to the healthcare system in 2020, and it will continue to do so in 2021. Remarkably, by late November 2020, two anti-SARS-CoV antibody products, bamlanivimab and the casirivimab and imdevimab cocktail, were authorized for emergency use by the US Food and Drug Administration (FDA) and the repurposed antibodies levilimab and itolizumab had been registered for emergency use as treatments for COVID-19 in Russia and India, respectively. Despite the pandemic, 10 antibody therapeutics had been granted the first approval in the US or EU in 2020, as of November, and 2 more (tanezumab and margetuximab) may be granted approvals in December 2020.* In addition, prolgolimab and olokizumab had been granted first approvals in Russia and cetuximab saratolacan sodium was first approved in Japan. The number of approvals in 2021 may set a record, as marketing applications for 16 investigational antibody therapeutics are already undergoing regulatory review by either the FDA or the European Medicines Agency. Of these 16 mAbs, 11 are possible treatments for non-cancer indications and 5 are potential treatments for cancer. Based on the information publicly available as of November 2020, 44 antibody therapeutics are in late-stage clinical studies for non-cancer indications, including 6 for COVID-19, and marketing applications for at least 6 (leronlimab, tezepelumab, faricimab, ligelizumab, garetosmab, and fasinumab) are planned in 2021. In addition, 44 antibody therapeutics are in late-stage clinical studies for cancer indications. Of these 44, marketing application submissions for 13 may be submitted by the end of 2021. *Note added in proof on key events announced during December 1-21, 2020: margetuximab-cmkb and ansuvimab-zykl were approved by FDA on December 16 and 21, 2020, respectively; biologics license applications were submitted for ublituximab and amivantamab.

The pace of antibody therapeutics development accelerated in 2017, and this faster pace is projected to continue through 2018. Notably, the annual number of antibody therapeutics granted a first approval in either the European Union (EU) or United States (US) reached double-digits (total of 10) for the first time in 2017. The 10 antibodies granted approvals are: brodalumab, dupilumab, sarilumab, guselkumab, benralizumab, ocrelizumab, inotuzumab ozogamicin, avelumab, duvalumab, and emicizumab. Brodalumab, however, had already been approved in Japan in 2016. As of December 1, 2017, nine antibody therapeutics (ibalizumab, burosumab, tildrakizumab, caplacizumab, erenumab, fremanezumab, galcanezumab, romosozumab, mogamulizumab) were in regulatory review in the EU or US, and regulatory actions on their marketing applications are expected by the end of 2018. Based on company announcements and estimated clinical study primary completion dates, and assuming the study results are positive, marketing applications for at least 12 antibody therapeutics that are now being evaluated in late-stage clinical studies may be submitted by the end of 2018. Of the 12 candidates, 8 are for non-cancer indications (lanadelumab, crizanlizumab, ravulizumab, eptinezumab, risankizumab, satralizumab, brolucizumab, PRO140) and 4 are for cancer (sacituzumab govitecan, moxetumomab pasudotox, cemiplimab, ublituximab). Additional antibody therapeutics to watch in 2018 include 19 mAbs undergoing evaluation in late-stage studies with primary completion dates in late 2017 or during 2018. Of these mAbs, 9 are for non-cancer indications (lampalizumab, roledumab, emapalumab, fasinumab, tanezumab, etrolizumab, NEOD001, gantenerumab, anifrolumab) and 10 are for cancer indications (tremelimumab, isatuximab, BCD-100, carotuximab, camrelizumab, IBI308, glembatumumab vedotin, mirvetuximab soravtansine, oportuzumab monatox, L19IL2/L19TNF). Positive clinical study results may enable marketing application submissions in 2018. Brief summaries of these antibody therapeutics are provided in this installment of the ‘Antibodies to watch’ article series.

In this 13th annual installment of the annual ‘Antibodies to Watch’ article series, we discuss key events in commercial antibody therapeutics development that occurred in 2021 and forecast events that might occur in 2022. Regulatory review of antibody therapeutics that target the SARS-CoV-2 coronavirus proceeded at an unprecedented pace in 2021, resulting in both emergency use authorizations and full approvals for sotrovimab, regdanvimab, REGEN-COV2, as well as others, in numerous countries. As of November 1, a total of 11 antibody therapeutics had been granted first approvals in either the United States or European Union in 2021 (evinacumab, dostarlimab loncastuximab tesirine, amivantamab, aducanumab, tralokinumab, anifrolumab, bimekizumab, tisotumab vedotin, regdanvimab, REGEN-COV2). The first global approvals of seven products, however, were granted elsewhere, including Japan (pabinafusp alfa), China (disitamab vedotin, penpulimab, zimberelimab), Australia (sotrovimab, REGEN-COV2), or the Republic of Korea (regdanvimab). Globally, at least 27 novel antibody therapeutics are undergoing review by regulatory agencies. First actions by the Food and Drug Administration on the biologics license applications for faricimab, sutimlimab, tebentafusp, relatlimab, sintilimab, ublituximab and tezepelumab are expected in the first quarter of 2022. Finally, our data show that, with antibodies for COVID-19 excluded, the late-stage commercial clinical pipeline of antibody therapeutics grew by over 30% in the past year. Of those in late-stage development, marketing applications for at least 22 may occur by the end of 2022.

Background Immune checkpoint therapies (ICTs) targeting the programmed cell death-1 (PD1)/programmed cell death ligand-1 (PD-L1) pathway have improved outcomes for patients with non-small cell lung cancer (NSCLC), particularly those with high PD-L1 expression. However, the predictive value of manual PD-L1 scoring is imperfect and alternative measures are needed. We report an automated image analysis solution to determine the predictive and prognostic values of the product of PD-L1+ cell and CD8+ tumor infiltrating lymphocyte (TIL) densities (CD8xPD-L1 signature) in baseline tumor biopsies. Methods Archival or fresh tumor biopsies were analyzed for PD-L1 and CD8 expression by immunohistochemistry. Samples were collected from 163 patients in Study 1108/NCT01693562, a Phase 1/2 trial to evaluate durvalumab across multiple tumor types, including NSCLC, and a separate cohort of 199 non-ICT- patients. Digital images were automatically scored for PD-L1+ and CD8+ cell densities using customized algorithms applied with Developer XD™ 2.7 software. Results For patients who received durvalumab, median overall survival (OS) was 21.0 months for CD8xPD-L1 signature-positive patients and 7.8 months for signature-negative patients ( p = 0.00002). The CD8xPD-L1 signature provided greater stratification of OS than high densities of CD8+ cells, high densities of PD-L1+ cells, or manually assessed tumor cell PD-L1 expression ≥25%. The CD8xPD-L1 signature did not stratify OS in non-ICT patients, although a high density of CD8+ cells was associated with higher median OS (high: 67 months; low: 39.5 months, p = 0.0009) in this group. Conclusions An automated CD8xPD-L1 signature may help to identify NSCLC patients with improved response to durvalumab therapy. Our data also support the prognostic value of CD8+ TILS in NSCLC patients who do not receive ICT. Trial registration ClinicalTrials.gov identifier: NCT01693562 . Study code: CD-ON-MEDI4736-1108. Interventional study (ongoing but not currently recruiting). Actual study start date: August 29, 2012. Primary completion date: June 23, 2017 (final data collection date for primary outcome measure). Electronic supplementary material The online version of this article (10.1186/s40425-019-0589-x) contains supplementary material, which is available to authorized users.