Vaccinex announced positive interim response data in a Phase Ib study assessing pepinemab in combination with Merck’s vaunted checkpoint inhibitor, Keytruda.
Shares of Vaccinex are soaring this morning after the company announced positive interim response data in a Phase Ib study assessing a combination of the company’s humanized IgG4 monoclonal antibody pepinemab in combination with Merck’s vaunted checkpoint inhibitor, Keytruda.
Rochester, N.Y.-based Vaccinex, Inc. said interim data from its Phase Ib study in patients with recurrent or metastatic head and neck squamous cell carcinoma is already showing significant promise. Of the three patients enrolled in the safety segment of the study, two have been observed to experience a complete response. Vaccinex pointed to a biomarker analysis that showed tumors in both patients show low levels of PD-L1.
The safety observation portion of the study, dubbed KEYNOTE-B84, was established to assess potential Dose Limiting Toxicity (DLT) for pepinemab, Vaccinex’s monoclonal antibody inhibitor of SEMA4D, which regulates chronic inflammation in the tumor microenvironment. Following the dosing of the patients, the research team closely monitored them. After five weeks, a biopsy of the target lesion was taken and additional scans of the tumor were made at week nine. It was found that two of the three patients had experienced a complete response to the treatment.
The third patient was determined to have cancer of the tongue and trial investigators observed clinical progression of his condition. However, the patient withdrew from the study at week six, prior to the first radiologic tumor response assessment at week nine. According to the company, the patient was not evaluated for tumor response. In addition, Vaccinex reported that the patient did suffer a number of serious adverse events, including dehydration and hyperglycemia. Those were attributed to a pre-existing diabetes diagnosis and were considered unrelated to the combination treatment.
Maurice Zauderer, Ph.D., president and chief executive officer of Vaccinex, said the results show a strong rationale for the continued development of pepinemab in combination with Keytruda in head and neck squamous cell carcinoma. Zauderer said these tumors are known to express high levels of SEMA4D. Earlier studies conducted by Vaccinex have shown that SEMA4D induces increased numbers and activity of myeloid suppressor cells that inhibit immune responses. Additional data from previous preclinical and clinical studies of pepinemab show the drug candidate promoted activation of dendritic cells/ CD8+ T-cells and reverses immunosuppression within the tumor.
Further results from the ongoing study will be shared at a future medical conference. Zauderer added that the ongoing study is accruing patients in the now open expansion phase, which is expected to include up to 62 additional patients.
