On June 2, 2024 Merus N.V. (Nasdaq: MRUS) (Merus, the Company, we, or our), a clinical-stage oncology company developing innovative, full-length multispecific antibodies (Biclonics and Triclonics), reported updated interim clinical data on MCLA-145 monotherapy and in combination with pembrolizumab were presented at the 2024 American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Annual Meeting taking place in Chicago May 31-June 4, 2024 (Press release, Merus, JUN 2, 2024, View Source [SID1234643934]).

Schedule your 30 min Free 1stOncology Demo!
Discover why more than 1,500 members use 1stOncology™ to excel in:

Early/Late Stage Pipeline Development - Target Scouting - Clinical Biomarkers - Indication Selection & Expansion - BD&L Contacts - Conference Reports - Combinatorial Drug Settings - Companion Diagnostics - Drug Repositioning - First-in-class Analysis - Competitive Analysis - Deals & Licensing

                  Schedule Your 30 min Free Demo!

"MCLA-145 as monotherapy or with pembrolizumab appears to have a manageable safety profile and early clinical activity in these difficult to treat cancers. Our biomarker data suggest that both dose and less frequent administration may be important determinants of clinical activity, and we are encouraged by the progress we are making with MCLA-145," said Bill Lundberg, M.D., President, Chief Executive Officer of Merus. "As our company is now increasingly focused on our lead asset petosemtamab and plan to initiate phase 3 trials in head and neck cancer later this year, we aim to advance clinical development of MCLA-145 in the context of a potential collaboration."

MCLA-145 (CD137 x PD-L1 Biclonics): Solid Tumors
Interim data included in the presentation describe data from patients (pts) with advanced/metastatic solid tumors who received MCLA-145 Q2W in 28 day cycles or every three weeks (Q3W) in 21 day cycles. Pts treated with the combination of MCLA-145 and pembrolizumab had cancers that either relapsed after PD-(L)1 therapies or were immunotherapy (IO) naïve.

Rapid oral presentation title: Phase I study of MCLA-145, a bispecific antibody targeting CD137 and PD-L1, in solid tumors, as monotherapy or in combination with pembrolizumab
Observations in the presentation include:

As of a January 3, 2024 data cutoff date, 72 pts with multiple cancer types were treated; 25% of pts had non-small cell lung cancer (NSCLC)
All patients were heavily pre-treated with a median of 3 prior therapies; prior IO in 49% of the monotherapy pts and 100% of the combination pts
In monotherapy, 52 pts with a variety of tumor types and treated at different dose levels were evaluable for response
5 partial responses (PRs) were observed at different dose levels in glioblastoma (ongoing as of the cutoff date for >3 years), sarcoma (pretreated with pazopanib and gemcitabine/docetaxel), cervical, anal, and gastric cancer by Response Evaluation Criteria in Solid Tumors v1.1. per investigator assessment
2 of 6 pts PRs (33%) were observed for pts treated at the recommended dose for expansion (RDE), 40 mg Q3W
3 of 6 PRs (50%) were observed for pts with evaluable baseline tumor CD8 T-cell density of ≥ 250 cells/mm2 responded
In combination with pembrolizumab, 19 pts with a variety of tumor types and treated at different dose levels were evaluable for response
1 PR in Merkel cell carcinoma was observed at 25 mg Q3W
1 complete response was observed in PD-L1+ NSCLC at the RDE 40 mg Q3W
3 pts were continuing combination therapy at cutoff date
MCLA-145 monotherapy or in combination with pembrolizumab had a well-tolerated and manageable safety profile at the RDE, 40mg Q3W
Shifting from Q2W to Q3W resulted in a 50% reduction of Grade (G) ≥3 treatment-emergent adverse events in both monotherapy and combination therapy
Liver toxicity, a common CD137 related adverse event, was controlled with no G4 events observed at Q3W
The full presentation is available on the Merus website.