Key person interview

SymBio Pharmaceuticals Limited Translational Research Department Medical Advisor Dr. Satoshi Kamiya
Tackling Broad Indications with Brincidofovir:
Achievements So Far and Expectations for the Future
Translational Research Division,
Medical Advisor MD, PhD
Tetsu Kamitani

Question 1. Could you tell us about your area of expertise and your role at SymBio Pharmaceuticals?

My area of expertise is clinical immunology, which includes fields such as tumor immunology and infectious disease immunology. This also encompasses my research on immunology against viral infections. At present, I am part of the Translational Research Division at SymBio Pharmaceuticals, where I am responsible for preclinical trials. Specifically, I am focusing on trials related to solid tumors.

Question 2. How did you come to be involved in research on solid tumors?

Brincidofovir, the drug we are currently working on, was initially developed as an antiviral medication. Accordingly, we have conducted preclinical and clinical trials targeting viral infections. I would like to explain why we have now ventured into the field of oncology.      Some of the viruses that brincidofovir is effective against are associated with cancer development. For cancers linked to such viruses, we hypothesized that suppressing the viruses with brincidofovir might inhibit tumor growth. Indeed, our preclinical trials confirmed that brincidofovir is effective against several types of cancer. Surprisingly, we also discovered that brincidofovir is effective not only against virus-related cancers but also against cancers with no proven viral association. Given my expertise in clinical immunology related to viral infections and tumors, I was assigned to handle solid tumors at SymBio Pharmaceuticals.

SymBio Pharmaceuticals Limited Translational Research Department Medical Advisor Dr. Satoshi Kamiya

Question 3. Does SymBio Pharmaceuticals have any advantages as it expands its business from hematological cancers to solid tumors?

SymBio Pharmaceuticals is currently marketing a hematological cancer treatment called "Treakisym." Building upon this successful foundation, our expansion into solid tumors benefits significantly from the expertise of our personnel with extensive knowledge and experience in the oncology domain.

Question 4. Could you share the preclinical trial results on solid tumors conducted through the end of 2024?

Nearly all of our preclinical trials on solid tumors were conducted in 2024, leading to substantial progress. Our initial step was to conduct in vitro experiments using cultured cells to determine whether brincidofovir was effective against solid tumors. Specifically, we added brincidofovir to culture media and observed the extent to which cancer cells were eradicated. We tested over 50 types of cultured solid tumor cells to evaluate its effects.                                                                                                                                              As a result, we identified over 10 types of cancer cells for which brincidofovir was particularly effective. Conversely, we also found some cancer cells where brincidofovir had minimal effect. Based on these findings, we progressed to the next step: animal testing.                  In the animal trials, we used specialized humanized mice, which are mice engrafted with human immune cells. These mice were implanted with human cancer cells, and brincidofovir was administered as a treatment. The trials yielded several intriguing findings. In addition to directly killing cancer cells, brincidofovir was also confirmed to kill cancer cells indirectly via immune cells. So far, we have verified brincidofovir’s antitumor effects in multiple types of cancer.

Question 5. What are your thoughts on combining brincidofovir with immunotherapy?

In our mouse experiments, we found that brincidofovir was highly effective even as a monotherapy. However, a certain dosage was required to achieve these effects. When combined with immunotherapy, brincidofovir demonstrated sufficient efficacy even at low doses. This combination therapy showed outcomes comparable to or even superior to current standard treatments. If future clinical developments proceed smoothly, brincidofovir may potentially replace existing standard therapies.

Question 6. Brincidofovir is currently being developed for multiple indications across three disease areas (post-transplant infections, hematologic and solid cancers, and neurological diseases). Could you elaborate on its potential?

Viral Infections:
Brincidofovir exhibits broad-spectrum efficacy against multiple viruses, rather than targeting a specific virus. This is a significant advantage over conventional antiviral drugs, which are typically effective against only one type of virus. Brincidofovir’s ability to treat multiple viral infections underscores its enormous potential in this area.

Oncology:
Initially, preclinical trials were conducted for Epstein-Barr virus (EBV)-related lymphomas, confirming brincidofovir’s antitumor effects. Subsequently, it was revealed that brincidofovir is effective not only for hematologic cancers but also cancers unrelated to viruses. This expanded scope highlights brincidofovir’s promising potential to address various types of cancer.

Neurological Diseases:
Brincidofovir is also expected to be effective against neurological diseases such as multiple sclerosis and Alzheimer’s disease. For example, evidence suggests that herpes simplex virus, against which brincidofovir has antiviral activity, may play a role in the pathogenesis of Alzheimer’s disease. Collaborative research with Tufts University demonstrated the efficacy of brincidofovir in an Alzheimer’s disease model triggered by herpes simplex virus reactivation. This example illustrates brincidofovir’s potential to offer new possibilities for treating neurological diseases that currently lack sufficient therapeutic options.

Across these three disease areas, brincidofovir exhibits remarkable potential. We anticipate further breakthroughs through continued research and development.

Question 7. You attended the J.P. Morgan Healthcare Conference in January 2025. Could you share the purpose, your role, and the outcomes of that conference?

The J.P. Morgan Healthcare Conference was held in San Francisco, USA, in January 2025. At this conference, many companies presented their activities and progress while also engaging in Q&A sessions. Our team at SymBio Pharmaceuticals participated in the conference and held meetings with investors who also attended.
My role was to explain the activity and potential of brincidofovir. I shared detailed information on its preclinical efficacy in the areas of viral infections, neurological diseases, and oncology, as well as our plans for future development. We were able to convey the potential of brincidofovir to investors and gain their understanding and support.
Moreover, through direct conversations with investors, we gained valuable insights into their areas of interest and perspectives on our initiatives. This was a highly meaningful experience that provided us with knowledge beneficial for our future activities.

SymBio Pharmaceuticals Limited Translational Research Department Medical Advisor Dr. Satoshi Kamiya

Question 8. Could you tell us about the outcomes related to partnerships at the conference?

We held discussions with several companies regarding potential partnerships. Among these, there were multiple companies that expressed strong interest in our work. Moving forward, we plan to continue discussions with these companies and prepare for concrete collaborations.

Question 9. Finally, could you share your aspirations for the future with your shareholders?

Brincidofovir holds immense potential across the three disease areas I mentioned earlier. Preclinical trial results have already demonstrated its efficacy in each of these areas, and we anticipate further breakthroughs as we proceed with clinical trials.
In particular, brincidofovir's efficacy across a wide range of diseases suggests that it could pave the way for new standard treatments that go beyond current therapies. I encourage our shareholders to remain optimistic about our ongoing research and development activities. We are fully committed to maximizing brincidofovir's potential and will continue to work tirelessly toward that goal.         Thank you for your continued support.