Garo Armen
Analyst · H.C. Wainwright
Thank you, Zack. Ladies and gentlemen, as we gather today for the earnings call, let's reflect on the remarkable patient outcomes from our botensilimab trials. As underscored by our leading experts and researchers, we're witnessing sustained benefits in treating some of the most challenging cancers. Based on these observations and for the sake of cancer patients, our urgent mission is to set a new benchmark in cancer care, providing patients with longer-term potentially curative benefit with some patients experiencing treatable toxicities.
Our BOT therapy is showing promise across various cancer stages and types with benefits seen in some of the most treatment-resistant so-called cold tumors. In addition, recent data presented at our corporate event in Madrid during ESMO revealed BOT potential in earlier stages of cancer where remarkable rapid responses were observed with the possibility to prevent significant treatment-related morbidities, including the potential need for colostomy.
Moving forward, we're concentrating on 3 key priorities: submitting our first biologics license application for colorectal cancer; prioritizing other clinical programs with the potential for rapid approval; and importantly, to mark reallocating resources to achieve our goals. Accordingly, we're gearing up our first BOT/BAL BLA submission in mid-2024 with a focus on late-stage colorectal cancer. Dr. Yancey will delve deeper into this topic shortly.
The cancer community's enthusiasm and rapid enrollment in our Phase II clinical trial in MSS CRC highlights an urgent unmet need. To address this, we have started a compassionate use program with the aim of broadening it into an expanded access program next year.
With very limited options to treat patients with advanced colorectal cancer, the positive trends and lasting responses in our studies strengthen our conviction in BOT/BAL's potential. Our top priority is obtaining BOT/BAL's approval in MSS CRC in order to allow patients access to this important IO treatment, offering them new hope which does not exist today.
Our second area of focus is advancing our prioritized clinical programs, which includes refractory pancreatic cancer and neoadjuvant setting in CRC. Dr. O'Day will detail the exciting data that showcases BOT potential in these cold solid tumors.
In addressing our financial capabilities to drive our objectives, we're already taking and continue to take steps to contain costs. These steps are important, particularly given the current challenging environment in the biotech sector. Our immediate prospects for additional cash infusion that does not involve stock issuance include the milestone payment from one of our partnered programs expected by the end of December 2023. That's this year.
In addition to this expected milestone, we are in the process of the sale of 2 nonstrategic assets and pursuing the partial sale of milestones and royalties due to Agenus from our partnered programs. These 3 sales are expected to close by the end of the first half of 2024. The potential proceeds from these 4 transactions are estimated at approximately $200 million in total.
With our cash balance at the end of Q3 along with these 4 planned transactions, we believe we are sufficiently funded through the end of 2024. In addition to these planned transactions, we're also in advanced discussions for a potential structured financing for BOT/BAL as well as a potential corporate collaboration with a large pharma or biotech company.
That ends my formal remarks, introductory remarks, and now I'll be handing it over to Dr. O'Day to shed light on our latest findings and data updates. Steven?
Steven O’Day: Thank you, Garo. Together with our investigators and key opinion leaders, we presented updates from the BOT/BAL development program at a corporate event hosted during the Madrid ESMO Congress in October. I'll now briefly describe these data updates, beginning with colorectal cancer.
We updated our Phase Ib cohort of 70 evaluable patients with BOT and BAL in refractory MS-stable colorectal cancer without active liver metastasis. This is the target population for our fully enrolled Phase II study and the population in which we've received Fast Track designation from the FDA.
The RECIST confirmed overall response rate was 24%. The duration of response was not reached with 59% of responses ongoing and now a median follow-up updated to 12.3 months. These patients showed a 12-month overall survival rate of 74%, approximately twice that reported for standard of care.
With longer follow-up, the median OS previously reported at 20.9 months is now no longer reached. Importantly, the OS curve plateau continues to emerge and strengthen as the data matures with the longest patient now alive at 3.5 years and 3 other patients who are alive beyond 21 months. We plan to file our initial BLA in this indication in mid-2024.
Next, we presented data from an investigator-sponsored trial at WOW Cornell, in which 12 patients with CRC were treated with 1 dose of BOT and 2 doses of BAL in the neoadjuvant therapy window of opportunity setting. Surgery was performed, on average, only 4 weeks after the initiation of immunotherapy.
All 3 MSI high colorectal patients had complete or near complete pathologic responses and, even more importantly, 6 out of 9 patients with MS-stable colorectal cancer had pathologic responses of 50% or greater, including 2 complete pathologic responses. None of the 12 patients had tumor growth during the treatment interval and no surgeries were delayed due to immune-related toxicities.
These results represent an important opportunity to move into earlier lines of therapy with curative intent and change the treatment paradigm for MS-stable colorectal cancer, potentially avoiding the morbidity of late-line therapies.
In second-line pancreatic cancer, we have treated 6 patients with the combination of botensilimab, Gemzar and Abraxane triplet. All 6 patients had progressed following first-line metastatic FOLFIRINOX therapy, and all 6 have liver metastasis. Four of the 6 patients have achieved marked and sustained tumor marker reductions.
Two of the 4 patients have already achieved partial responses at 16 weeks with target lesion reduction of minus 47%, which has been confirmed and minus 37%, which is pending confirmation scans, and both responses are ongoing. Two other patients showed stable disease at their first 8-week scans with tumor reduction of minus 20% and minus 13%, and they remain on study awaiting 16-week scan.
A randomized Phase II study is currently enrolling and a data update is anticipated in the first half of 2024. Our other Phase II trial is in refractory metastatic melanoma, including PD-1 refractory as well as PD-1 CTLA-4 refractory disease. In a Phase Ib expansion cohort of 10 patients, botensilimab alone showed a 30% objective response rate and 60% disease control rate in these refractory patients.
In the Phase II study, the botensilimab monotherapy cohort is now fully enrolled, and the botensilimab/balstilimab combination cohort is enrolled with approximately 30 patients. A data update is anticipated in the second half of 2024.
In PD-L1 refractory non-small cell lung cancer, we reported on 9 patients who were treated with the combination of BOT and BAL. Five of the 9 patients in the combination achieved RECIST-confirmed partial responses for an ORR of 56% and a disease control rate of 89%. Approximately 50 patients have now been enrolled in 2 expansion cohorts, including PD-1 refractory as well as TKI driver mutation refractory disease. A data update is anticipated in mid-2024.
Dr. Bree Wilky, Director of the Sarcoma Medical Oncology, Deputy Associate Director for Clinical Research at the University of Colorado Cancer Center presented an update of botensilimab program in sarcomas at ESMO 2023. In 41 evaluable heavily pretreated sarcoma patients, the combination of BOT and BAL demonstrated an overall response rate of 20%, a median duration of response of 19.4 months and a 6-month progression-free survival of 40%. There were differential responses observed by dose level with 29% response rate in the 2-milligram per kilo BOT cohort compared to 15% in the 1 milligram per kilo BOT cohort.
In addition, we observed promising activity and difficult-to-treat subtypes of sarcoma, such as leiomyosarcoma and visceral angiosarcoma. The results we've achieved in cold tumors in both the refractory setting and, more recently, in early disease offers hope for patients and families where current standards of care are an adequate or limited benefit.
The robustness of our data broadly across tumor types resulting in deep and durable responses showcases a potential groundbreaking advancement in oncology for botensilimab. We remain committed to improving patient outcomes and are grateful for the support of our team, trial participants and stakeholders. I am confident in the positive impact we are making, and I'm excited about the future.
Now I'll turn the call over to Todd to discuss our regulatory strategy.