The American Association for Cancer Research’s annual conference continued Tuesday with Marengo Therapeutics making progress against colorectal cancers resistant to PD-1 therapies and BriaCell highlighting potential response biomarkers.
The American Association for Cancer Research’s annual conference is in full swing, with Boehringer Ingelheim, Merck, GSK, Roche and more presenting new data for oncology cornerstones and investigational candidates.
Meanwhile, on Sunday, AACR CEO Margaret Foti closed the event’s opening ceremony with a rare condemnation of the Trump administration’s science and health policy moves since January, STAT News reported.
Stay tuned to BioSpace as we keep you updated on all of the biggest data and news as the conference continues this week.
Updated: April 30, 9:00 a.m. CST/10:00 a.m. EST
BriaCell’s Novel Immunotherapy Elicits Positive Survival Data In PIII Breast Cancer Trial
BriaCell Therapeutics, a Philadelphia and Vancouver-based biotech, supported its lead immunotherapy candidate, BRIA-IMT, with new data from a Phase III trial in metastatic breast cancer.
In a poster presentation at AACR 2025, the company showed that in a trial of 62 patients, BRIA-IMT gained patients a progression-free survival rate of 3.67 months. The presentation focused mostly on positive biomarkers associated with the treatment, including changes in circulating tumor cells, which were associated with better survival numbers (3.8 months versus 2.4 in patients with higher tumor cell counts), and a favorable neutrophil-to-lymphocyte ratio, a standard measure of inflammation.
BRIA-IMT is a genetically engineered human breast cancer cell line, altered to have features of an immune cell. BRIA-IMT’s mechanism of action isn’t known, according to the biotech’s website, but it’s hypothesized that the drug might stimulate the body’s immune system to destroy a growing breast cancer cell population.
Marengo Targets PD-1 Resistance With Dual T Cell Agonist
Marengo Therapeutics’ investigational bispecific T cell activator invikafusp alfa elicited a 30% objective response rate across all three major subtypes of colorectal cancer (CRC) in an early-stage trial, according to a readout presented Tuesday at AACR 2025.
Marengo’s Phase I/II STARt-001 trial tested invikafusp alfa as a single-agent therapy in certain patients with antigen-rich solid tumors, including those that are refractory to PD-1 therapies. Tuesday’s data come from 10 patients with high tumor mutational burden treated at the effective dose range of invikafusp alfa.
Disease control rate in these patients was 61%. Meanwhile, tumor regression rate hit 52% across various tumor types, such as CRC, non-small cell lung cancer, melanoma and head and neck cancer. As for safety, Marengo’s documented side effects were consistent with drugs that work via selective T cell activation. Toxicities were temporary and manageable with clinical care.
STARt-001 also validated invikafusp alfa’s mechanism of action, demonstrating strong and selective expansion of a subset of CD8-positive cells that can activate specific T cells, in turn promoting their anti-cancer activity. Treatment with invikafusp alfa in the study also led to the expansion of these particular anti-cancer T cells in tumor tissues.
Artios’ Oral ATR Blocker Elicits Response in Half of Patients With Metastatic Solid Tumors
In the Phase I/IIa STELLA study, more than a third of patients treated with Artios Pharma’s investigational ATR inhibitor ART0380 plus low-dose irinotecan, had a confirmed treatment response.
These data, presented during an oral session at AACR 2025, come from 38 patients with advanced or metastatic solid tumors who had no other satisfactory treatment options available to them. These study participants were treated with 200-mg ART0380—its recommended Phase II dose—and 60-mg/m2 irinotecan at specified intervals.
These patients were also deficient for the ataxia-telangiectasia mutated (ATM) protein, a key marker for replication stress that is present in up to a quarter of high–unmet need solid tumors, according to Artios.
Tuesday’s data showed the ART0380 regimen resulted in a 37% confirmed overall response rate (cORR) in these patients. In the subgroup of patients negative for the ATM marker, cORR was 50%, with a median response duration of 5.7 months. In those whose tumors tested positive for ATM but who showed low levels of the protein, cORR was 22%, while median duration of response had not yet been reached at the time of readout.
Artios noted that ART0380 could elicit treatment responses against eight tumor types, including pancreatic and colorectal cancer.
Roche’s TIGIT Postmortem Bares Details of High-Profile Lung Cancer Flop
When Roche announced that its anti-TIGIT therapy tiragolumab failed the SKYSCRAPER-01 trial in non-small cell lung cancer in November 2024, it didn’t provide much detail, leaving the industry guessing at how bad the miss was.
That changed on Monday, when the pharma unveiled its detailed analysis of the study, showing that tiragolumab combined with the PD-1 blocker Tecentriq lowered the risk of disease progression or death by 28% versus Tecentriq alone. This effect fell short of statistical significance, with a p-value of 0.02.
Median overall survival in the tiragolumab group was 23.1 months, versus 16.9 months in controls. This translated to a 13% drop in the risk of death from any cause, an effect that also failed to reach significance.
As for safety, Roche reported a higher occurrence of toxicities in tiragolumab-treated patients, including immune-mediated side effects such as rashes, hepatitis and hypothyroidism.
Despite the Phase III miss, the pharma nevertheless emphasized tiragolumab’s “numerical improvements” in progression-free and overall survival, which it claimed “suggest potential antitumor activity of combination PD-L1/TIGIT targeting in NSCLC.”
Agenus’ PD-1/CTLA-4 Combo Therapy Demonstrates ‘Strong’ Activity in Solid Tumors
On Monday, Agenus unveiled data from the Phase II NEOASIS trial, touting encouraging response rates for its investigational PD-1/CTLA-4 therapy BOT/BAL in early-stage solid tumors.
In an investor note on Tuesday, Willaim Blair analysts called these data “promising,” noting that pathological response data in the mismatch repair-proficient/microsatellite stable (MSS) cohort is “impressive.”
BOT/BAL is a combination therapy composed of two drugs: the anti-CTLA-4 antibody botensilimab and the PD-1 blocker balstilimab. NEOASIS is testing this investigational combo in the neoadjuvant setting for patients with non-metastatic solid tumors.
Data presented at AACR showed that in the subgroup of patients with mismatch repair-deficient/microsatellite instability-high tumors—nine had colorectal cancer and one had duodenal cancer—BOT/BAL elicited a 90% pathological response rate and a 70% pathological complete response rate (pCR).
Meanwhile, in those with MSS disease, pathological response was 80% while pCR was 20%. This subgroup included six patients with triple-negative breast cancer, two with ER-positive breast cancer, one with merkel cell carcinoma and another with sarcoma.
In July 2024, the FDA discouraged an accelerated approval pathway for BOT/BAL, noting that objective response rates in this context may not translate to survival outcomes. Accordingly, William Blair is currently awaiting word from Agenus regarding the candidate’s path forward, including a potential partnership to support its further development.
Merck Pads Case for Perioperative Keytruda in Advanced Head and Neck Cancer
Merck bolstered its case for Keytruda in head and neck cancer with data from a Phase III trial showing the blockbuster PD-1 inhibitor could elicit “significant survival benefits” in the perioperative setting.
In the Phase III KEYNOTE-689 study, Keytruda, as part of a perioperative treatment regimen also containing adjuvant standard of care (SOC) radiotherapy with or without cisplatin, improved event-free survival (EFS) by 27% in the study’s intention-to-treat population, besting a perioperative radiotherapy regimen alone.
The trial is the first “in more than two decades for patients with resected locally advanced head and neck squamous cell carcinoma,” according to Merck’s Sunday press release.
Merck filed a supplemental Biologics License Application with the FDA for Keytruda in this indication and is anticipating a decision by June 23.
For more details, please read the article.
GSK’s Jemperli Eliminates Need for Surgery in dMMR Locally Advanced Cancers
Phase II results presented Sunday showed that GSK’s PD-1 inhibitor Jemperli can trigger complete tumor clearance in patients with locally advanced, mismatch repair-deficient (dMMR) cancers, regardless of tumor type.
These data, published simultaneously in the New England Journal of Medicine, suggest that Jemperli could eliminate the need for surgery in these patients.
Sunday’s findings come from 103 patients with stage II-III resectable dMMR cancers: 49 with rectal cancer and 54 with nonrectal solid tumors such as gastroesophageal and genitourinary cancers. After treatment with Jemperli, all 49 patients with rectal cancer showed a clinical complete response and decided to forego surgical operation. Of these, 37 sustained their response levels through 12 months of follow-up.
Meanwhile, 35 patients with other cancer types reached clinical complete response, of whom 33 chose non-surgical management. Overall, 84 patients across both cohorts achieved complete response, 82 of whom decided to skip surgery.
Boehringer Ingelheim Touts Over 70% NSCLC Response Rate for Zongertinib
Boehringer Ingelheim’s investigational HER2 tyrosine kinase blocker zongertinib elicited a 71% objective response rate in certain patients with non-small cell lung cancer (NSCLC) in the Phase III Beamion LUNG-1 trial, according to a Monday readout.
The study focused on patients with advanced disease harboring HER2 mutations. Results showed that 7% of patients achieved complete treatment response, indicating no signs of disease. Partial response was 64%, while disease control rate was 96%. Median progression-free survival was 12.4 months.
Of note, zongertinib also demonstrated intracranial activity in 27 previously-treated patients with brain metastasis. In this subgroup, the candidate hit a response rate of 41% and a disease control rate of 81%.
Zongertinib was also safe overall in Beamion LUNG-1, with no drug-related instances of interstitial lung disease, cardiotoxicity or deaths. Adverse events grade 3 or higher were infrequent, and the most common side effect was diarrhea.
Boehringer Ingelheim filed its drug application for zongertinib in February, winning the FDA’s Priority Review designation. A decision is expected in the third quarter.
