By John Vandermosten, CFA
NASDAQ:BCTX
READ THE FULL BCTX RESEARCH REPORT
Bria-IMT Breast Cancer Efficacy Data
BriaCell (NASDAQ:BCTX) attended the 2022 San Antonio Breast Cancer Symposium in early December and presented several posters summarizing data from its Phase I/IIa clinical study of Bria-IMT and reviews preclinical efforts for the company’s next generation of products. In addition to details on individual patient performance in the trial and a summary of safety data, BriaCell also shared details on quality of life for patients examined indicators of clinical response including HLA matching and delayed type hypersensitivity. We provide the poster titles below and summarize salient their findings and conclusions.
BriaCell presented three posters at SABCS1 which we list below:
1. Allogeneic, Antigen-Presenting, GM-CSF-secreting, SV-BR-1-GM Whole Cell Therapeutic Vaccine in Advanced Metastatic Breast Cancer
2. Decreases in Circulating Tumor Associated Cells Predict PFS and OS in a Pooled Analysis of Phase I Clinical Trials Using SV BR 1 GM Therapy with or without Immune Check Point Inhibitors in Metastatic Breast Cancer Patients
3. Turning tumor cells into antigen presenting cells for cancer immunotherapy
The clinical trial for Bria-IMT, also designated SV-BR-1-GM, has enrolled 33 subjects in monotherapy study and 21 subjects in combination therapy with a PD-1 inhibitor, either Merck’s Keytruda (pembrolizumab) or Incyte’s retifanlimab. Patients that responded best in terms of disease control to both the monotherapy and combination therapy shared human leukocyte antigen (HLA) allele matches with the cell line used. For most subjects, the drug regimen effectively reduced tumor size.
BriaCell’s next generation of cellular immunotherapy is expected to address a broader population that should include near 99% of HLA phenotypes. Bria-OTS can be administered after HLA genotypying and does not require additional personalization. With the high degree of matching, Bria-OTS can be an off-the-shelf product that provides a dual mechanism of action with features of both cancer cells and dendritic cells that are expected to enhance the immune response in cancer patients. Bria-OTS can further be a precision therapy with improved safety relative to existing chemotherapy and hormone-based products.
CTC & CAML PD-L1 Expression
Circulating tumor cells (CTCs) and cancer associated macrophage-like (CAML) cells are indicators of cancer disease that is worsening. In a pooled analysis of 18 monotherapy patients and 21 combination therapy patients, investigators examined the predictive value of CTCs and CAMLs for progression free survival (PFS) and overall survival (OS) at 24 months. Results from the study are listed below:
➢ CTCs were found in 38% of patients and CAMLs in 95%.
➢ Baseline CTCs predicted worse OS but not PFS
➢ A decline in CTCs/CAMLs after therapy was seen in 67% of patients, correlating with better PFS
➢ A drop in CTCs/CAMLs was associated with a 4.6x increase in mPFS & a 1.7x increase in mOS
➢ Both mono and combination therapy groups saw a reduction in CTCs/CAMLs
Quality of Life
Investigators examined the quality of life for patients on the Bria-IMT combination regimen. This study, designated BRI-ROL-001, evaluated two cohorts of seven and ten as they progressed through the cycles of treatment. The study used the SF-36 quality of life questionnaire4 to determine the health of subjects in the trial. For those achieving disease control, subjects generally improved after each cycle. For others, the results were less conclusive. We include a graphic illustrating the results of BRI-ROL-001 below:
Another quality-of-life measure was also reviewed in the study which examined the change in pain relief as patients moved through cycles of treatment. Again, improvements in pain relief were noted for patients that were able to achieve disease control and patients that did not achieve disease control had less pain relief on average.
Delayed Type Hypersensitivity
Delayed Type Hypersensitivity (DTH) is greater in patients that respond to Bria-IMT in combination with PD-1 inhibitors. DTH is an inflammatory response that develops a day or two after exposure to an antigen that the immune system recognizes as foreign. This type of immune response involves mainly T cells rather than antibodies. Erythema and induration in patients treated with the combination regimen has appeared in 36% to 55% of patients that received Bria-IMT along with pembrolizumab. About 17% of patients displayed one of the two types of DTH in the Bria-IMT and retifanlimab combination. As shown in the following exhibit, patients that achieved the best outcome has larger measurable skin reactions.
SABCS Interviews
Dr. Bill Williams, BriaCell’s CEO, contributed to a series of interviews where he discusses the posters presented at SABSC and elaborates on other themes related to the company such as checkpoint inhibitors and the next generation of cellular immunotherapy.
➢ Bria-IMT Improving Patient Outcomes (1:47)
➢ Review of SABCS Posters (13:23)
➢ BriaCell and Checkpoint Inhibitors (7:09)
➢ Bria-OTS: Next Generation of Cellular Immunotherapy (8:53)
➢ Trends in Oncology: What’s Next? (10:01)
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1. Abstracts and authors can be found here.
2. Source: Screenshot from BriaCell Discusses SABCS Posters
3. Source: BriaCell Poster, SABC 2022. Allogeneic, Antigen-Presenting, GM-CSF-secreting, SV-BR-1-GM Whole Cell Therapeutic Vaccine in Advanced Metastatic Breast Cancer.
4. Link to representative questionnaire.
5. Source: BriaCell corporate presentation, December 8, 2022.
6. Source: BriaCell corporate presentation, December 8, 2022.
7. Source: BriaCell Poster, SABC 2022. Allogeneic, Antigen-Presenting, GM-CSF-secreting, SV-BR-1-GM Whole Cell Therapeutic Vaccine in Advanced Metastatic Breast Cancer.