More than a decade after Merck’s Keytruda and BMS’ Yervoy ushered in the immuno-oncology revolution, the space is at a crossroads, with experts highlighting novel targets, combinations and pre-emptive immunization as the next wave for IO.
Last year marked 10 years since Keytruda’s seminal approval. That FDA greenlight signaled a new day in immuno-oncology and set the stage for the subsequent approvals of several more checkpoint inhibitors. Now, the field is looking for its next breakthrough—but it’s been a bumpy road.
Overall, the immuno-oncology (IO) space “continues to be quite disappointing,” Graig Suvannavejh, senior biopharmaceuticals and biotechnology equity research analyst at Mizuho Americas, told BioSpace. “Industry is in search of that next great IO target, and they just haven’t been able to identify one that works.”
In the last 15 years, the FDA has approved 11 checkpoint inhibitors—therapies targeting immune checkpoint proteins, including PD-1 and its partner protein PD-L1, plus CTLA-4 and LAG-3—to help the immune system locate and attack cancer cells.
While Keytruda, an anti-PD-1, gets the most credit for having kickstarted the IO revolution, it was preceded by a CTLA-4 inhibitor called Yervoy, which BMS picked up in its $2.4 billion acquisition of Medarex in 2009. Two years later, the FDA approved Yervoy as the first anti-CTLA-4 drug. “That, really, along with the anti-PD-1s, kind of ushered in this whole immuno-oncology revolution,” Suvannavejh said.
Jeremy Levin, now CEO of Ovid Therapeutics who was instrumental in BMS’ transformation to an immuno-oncology company in the aughts, agreed: “It became increasingly clear that there was science that said that this whole concept of immune modulation was beginning to evolve, and that CTLA-4 was breaking open the first concepts behind it.”
Lately, however, the industry appears to have hit the proverbial therapeutic wall. But it’s not for a lack of trying, according to Christiana “Chris” Bardon, co-managing partner of MPM BioImpact.
“When PD-1 was first released, we spent a lot of energy as an industry looking for the next PD-1 and we must have had tens of thousands of combinations of drugs in the clinic, testing everything with PD-1,” she told BioSpace. “Basically, we were looking for the next-generation IO checkpoint inhibitor.”
But despite the emergence of more therapeutic options targeting the immune system, IO treatment response rates have plateaued at around 30%, Caroline Loew, CEO of Mural Oncology, wrote in a November 2024 opinion piece for BioSpace, meaning that 70% of patients do not respond to these therapies.
“Despite the incredible efficacy of PD-1,” Bardon said, there is still a huge unmet need. “We still have many cancers that don’t respond to PD-1, things that are immunologically cold.”
Striking Out With TIGITs
Branching out has proven difficult, however. In the IO space, Suvannavejh said anti-TIGIT checkpoint therapies have been “probably the biggest disappointment” in the past two years.
In December 2021, Roche ignited the field with promising results from the Phase II CITYSCAPE study of its anti-TIGIT drug tiragolumabin in metastatic non-small cell lung cancer (NSCLC). When combined with the company’s anti-PD-L1 blocker Tecentriq, tiragolumabin reduced the risk of disease worsening or death by 38% compared to Tecentriq alone.
“I think the IO space was in kind of a low place about five years ago until Roche announced positive Phase II data for their TIGIT antibody,” he said. “All of a sudden, people were like, ‘oh my god, IO is back.”
But in the Phase II/III data reported last year, the tiragolumab/Tecentriq combo failed to significantly improve progression-free and overall survival versus Keytruda and chemotherapy in patients with NSCLC and Roche elected to terminate that study. The excitement fizzled after that, Suvannavejh said.
It was almost the nail in the coffin for TIGITs, or at least the buzz around the drug class. Seven months earlier, in December 2023, Merck had struck out in NSCLC with its experimental anti-TIGIT antibody vibostolimab when the candidate, in combination with Keytruda, failed to hit the endpoints in a mid-stage study.
Recent results have breathed new life into the space, however. In September 2024, iTeos and GSK sparked excitement with Phase II results from patients with NSCLC taking a combination of iTeos’ anti-TIGIT candidate belrestotug and GSK’s anti-PD-1 therapy Jemperli. The combo elicited a 30% better confirmed objective response rate versus Jemperli alone. The partners are now studying the regimen as a first-line therapy for NSCLC in a Phase III trial.
While it remains to be seen if TIGIT-targeting checkpoint inhibitors will reach the market, Bardon noted that the industry has seen some progress with drugs that hit CTLA-4 and LAG-3. In October 2022, the FDA greenlit AstraZeneca’s anti-CTLA-4 drug Imjudo, in combination with its first-generation PD-L1 inhibitor Imfinzi, for hepatocellular carcinoma, while the LAG-3 space saw its first approval in March of that year in BMS’ relatlimab (in combination with Opdivo and marketed as Opdualag) in unresectable or metastatic melanoma.
Looking ahead, Bardo said ivonescimab—a PD-1/VEGF bispecific antibody in development by Summit Therapeutics, “is really the new . . . wave of checkpoint inhibitors.”
“Ivonescimab has shown superiority to PD-1 alone, which is incredible,” she said. In September, Summit presented Phase III data at the International Association for the Study of Lung Cancer’s 2024 World Conference on Lung Cancer, showing that ivonescimab outperformed Keytruda in first-line advanced NSCLC. In the HARMONi-2 trial, Summit’s candidate cut the risk of disease progression or death by nearly 50% compared with Keytruda.
While the results sent Summit’s stock skyrocketing by as much as 140%, some analysts urged caution, particularly noting that the data were from a trial run only in China. “Results may or may not be generalizable beyond the China-focused patient population initially assessed,” BMO Capital Markets wrote in an investor note at the time. Summit is currently studying ivonescimab in a multi-regional Phase III NSCLC study in the U.S.
Bardon added that ivonescimab has the potential to work in multiple tumor types outside of lung cancer and predicted that it would be “a huge blockbuster in the future.” Pfizer appears to agree. Last week, the New York–based pharma struck a deal with Summit to combine its vedotin-based antibody-drug conjugates with ivonescimab.
Part of the reason the industry has not been successful in developing checkpoint inhibitors “is that the development path is very, very hard,” Bardon said. One key challenge, she explained, is that most checkpoint therapies do not have monotherapy efficacy and therefore need to be developed in combination with PD-1 drugs. Definitive combination therapy can only be demonstrated in a comparator trial. “It’s just a very difficult and long path to de-risk the drug.”
In this way, ivonescimab benefited from being created and developed in China, where there are faster enrollment times, limited treatment options and clinical trials are less expensive, Bardon said.
Other IO targets of particular interest, Suvannavejh said, are PRAME (preferentially expressed antigen of melanoma) and the “very complicated RAS pathway, which includes the commonly mutated KRAS.”
“This is a pathway that people have been trying to target for decades,” Suvannavejh said. “[It is] very difficult to do, trying to get that mix of efficacy and safety.”
Amgen and BMS already have KRAS drugs— Lumakras and Krazati—on the market for NSCLC. The developmental “darling” of this space, Suvannavejh said, is Revolution Medicines, whose daraxonrasib is currently in a registrational trial to treat cancers with a wide range of common RAS mutations. Other players include Eli Lilly, Immuneering Corporation and Erasca.
IO Developments On the Horizon
Levin indicated that the IO space is at a crossroads. “The first wave of immuno-oncology has passed us by,” he said. “We know what we know about it.”
Biopharma’s appetite for IO is certainly understandable. For Merck, Keytruda brought in a cool $29.5 billion in global sales in 2024 and ranks among the best selling drugs of all time. With that drug going off patent in just a few years’ time, many companies are eager to grab more of a market that is projected to be worth more than $17 billion by 2032.
So, how does biopharma catch the next wave?
For Suvannavejh, the answer lies in identifying novel targets—potentially through artificial intelligence and machine learning. As an example, he offered Compugen, a Tel Aviv–based biotech that uncovered a previously unidentified checkpoint called PVRIG using its proprietary computational discovery platform. Compugen is currently studying the resulting asset, COM701, in trials of ovarian, gastric and other cancers.
“That’s what companies can do if they want to go down this path of like, hey, maybe there’s another checkpoint inhibitor that we just haven’t identified yet,” Suvannavejh said.
Meanwhile, Levin said the current focus is on combination therapies. “The world teaches you this repeatedly for complex diseases,” he continued, citing childhood leukemia, hypertension and congestive heart failure as examples of where combinations have ultimately been the answer.
However it’s done, Levin continued, the holy grail for IO is pre-emptively engaging the human body to defeat a cancer cell before it has even proliferated. “Immuno-oncology is the clue that you can do this,” he told BioSpace. “It says that you can absolutely galvanize the human tissue to reawaken attack on a cancer cell. The big question is, can you actually pre-emptively immunize us such that we can be ready for this?”
