KAHR Reports Dose Escalation Results from Phase I Trial of DSP107 in Combination with anti-PD-L1 in Patients with Advanced Solid Tumors

DSP107, a first-in-class CD47 and 4-1BB targeting fusion protein, in combination with atezolizumab, was well tolerated and demonstrated durable responses

Dose was determined for Phase II expansion cohorts in 3rd line MSS-CRC and 2nd/3rd line NSCLC

Data to be presented at ASCO 2023

MODI'IN, Israel, May 31, 2023 /PRNewswire/ -- KAHR, a clinical-stage biotech company developing DSP107, a novel, bi-specific CD47x4-1BB targeting immunotherapy that activates innate and adaptive immunity to treat solid tumors and blood cancers, today announced positive results from the dose escalation Phase I study of DSP107 in combination with atezolizumab (anti-PD-L1) in patients with advanced solid tumors. The results will be presented as a poster in the American Society of Clinical Oncology (ASCO) 2023 Annual Meeting, to be held June 2-6, in Chicago, IL.

Yaron Pereg, Ph.D., Chief Executive Officer of KAHR said, "We are extremely encouraged by the dose escalation data, showing significant tumor shrinkage and durable responses to DSP107 in combination with atezolizumab in patients with microsatellite stable colorectal cancer (MSS-CRC), which is considered a 'cold' tumor that usually does not elicit an efficient immune response. The highest dose of DSP107 (10 mg/kg) in the dose escalation phase was selected for the Phase II expansion cohorts in 3rd line MSS-CRC patients and 2nd/3rd line non-small cell lung carcinoma (NSCLC) patients. In light of DSP107's latest and previously demonstrated favorable safety profile, and the deep and long-lasting responses seen in the combination therapy dose escalation stage of the trial, we believe that DSP107 has the potential to benefit patients who are non-responsive or refractory to existing cancer treatments."

Results of the completed dose escalation part of the study show that DSP107 in combination with atezolizumab was well tolerated (n=19) with no dose limiting toxicities (DLT's) and no hematological or hepato-toxicities up to and including the highest dose tested (10 mg/kg).

At the highest dose (10 mg/kg) of DSP107, which was selected for the expansion cohorts, the combined treatment demonstrated a disease control rate (DCR) of 57% (4/7 patients with objective response or stable disease). Deep and durable objective responses were observed in 2 of 3 patients with MSS-CRC, with target lesion shrinkage of 73% and 83% including disappearance of pulmonary and hepatic target lesions in one patient and response durability currently standing at 10 and 9 months, respectively. The third MSS-CRC patient achieved stable disease (16% target lesion shrinkage) lasting for 6.5 months until progression. Another patient with adrenal carcinoma from the highest dose cohort also remains stable on treatment after 11 months. 

The combination therapy dose escalation phase of the study was an open label, multi-center trial (NCT04440735) that enrolled 19 patients with advanced solid tumors, with a median of 3 prior lines of therapy. Patients were treated weekly with 1, 3 or 10 mg/kg DSP107 infusions and atezolizumab (1200 mg) every three weeks, until disease progression. The primary objective was to determine the safety and tolerability of DSP107 in combination with atezolizumab. The secondary objective was to assess the preliminary efficacy of DSP107 in combination with atezolizumab.

Presentation information
Date: June 3rd, 2023, 8:00 am-4:00 pm
Session: Developmental Therapeutics – Immunotherapy
Abstract #2632
Poster #474

Abstract available on the ASCO website.

About DSP107

DSP107 is a dual-targeting fusion protein that activates innate and adaptive immunity by blocking CD47 on cancer cells and utilizing 4-1BB conditional co-stimulatory activation of T-cells. By binding both cancer cells and immune cells, DSP107 combines checkpoint inhibition with tumor localized immune cell activation to bolster anti tumor immunity. DSP107 binds to and inhibits CD47, an immune checkpoint protein overexpressed in many cancers that enables the tumor to evade immune recognition and attack by macrophages. Simultaneously, when anchored to the tumor, DSP107 binds 4-1BB, a co-stimulatory receptor expressed on T-cells, recruits them to the tumor microenvironment and stimulates their activation. These activities result in targeted macrophage and T-cell mediated immune activation and tumor destruction.

DSP107's phase I monotherapy dose escalation data demonstrated an excellent safety profile (n=23), with no binding to red blood cells and no dose limiting toxicities (DLT's), hematological or hepato-toxicities in all tested doses up to and including 10 mg/kg. Paired biopsies data demonstrated biological activity including immune cell infiltration in the tumor compartment following DSP107 treatment and 50% disease control rates (11/22) in advanced solid tumor patients.

DSP107 is also being tested in combination with standard of care therapies (azacytidine and azacytidine with venetoclax) for relapsed/refractory AML and MDS patients in a Phase 1b study.

About KAHR

KAHR develops novel dual-targeting fusion protein therapeutics engineered to activate both the innate and the adaptive immune systems simultaneously and localize that response in the tumor microenvironment. KAHR's lead product candidate, DSP107, is a CD47x41BB targeting compound. DSP107 is being tested in a Phase I/II clinical trial in advanced solid tumors and a Phase Ib clinical trial in blood cancers. KAHR's preclinical pipeline includes DSP502, a PVRxPD-L1 targeting fusion protein, and DSP216, an HLA-GxCD47 targeting fusion protein. For more information, please visit https://kahrbio.com/

Media contact
Tsipi Haitovsky
Global Media Liaison
KAHR
+972-52-598-9892
[email protected]

SOURCE KAHR Medical