Results of a recent clinical trial of Vaxil Bio’s (TASE:VAXL) ImMucin cancer vaccine in patients with multiple myeloma has validated the company’s VaxHit technology by demonstrating safety and a strong immune response in all patients.
“This is not trivial for a first-in-man study,” CEO Lior Carmon says in an interview with BioTuesdays.com, referring to 15 patients in the Phase 1/2 study who received some 150 injections in total, without any adverse side-effects. “For me, as an immunologist, the key outcome was the validation of the technology.”
Earlier this month, Vaxil said 100% of patients in the study demonstrated a strong immune response of both CD4+ and CD8+ T-cells to ImMucin. In addition, a strong antibody response to ImMucin was observed in 65% of patients.
Dr. Carmon notes the significance of the antibody response, pointing out that, to the best of the company’s knowledge, this combination of T-cells and antibodies does not exist in other MUC1 vaccines. “Moreover, these results in patients with a wide range of different immune repertoires support the company’s hypothesis of the ability of ImMucin to be universal – that it can activate the patient’s immune system with no need for personalization or prior selection based on the patient’s immune system type.”
Patients in the VAXIL-001 study received either six or 12 ImMucin injections at a dose of 100 or 250 micrograms, along with GM-CSF (Leukine) at a dose of 250 micrograms.
Vaxil contends that ImMucin teaches the patient’s immune system to identify and destroy cells that display the cancer marker MUC1 on the cell surface. Because MUC1 appears on over 90% of all cancers, ImMucin has the potential to be used as a vaccine against a wide range of cancers.
However, the specific epitope that ImMucin targets on MUC1 is different from the target used by other MUC1 vaccines; the ImMucin epitope only appears on tumor cells and does not appear in soluble form in the patient’s blood. This is a huge advantage, according to Dr. Carmon. If it were to appear in the blood, it could significantly interfere with the specific vaccine-induced immune response and hence reduce its effectiveness.
In addition to ImMucin’s specificity to MUC1, its strong and broad immune response, and potential universal use, Dr. Carmon says the vaccine also is unique in its ability to counter cancer’s attempt to hide from the immune system and develop resistance to treatment. A reduced need for an adjuvant also increases safety and reduces the cost of the vaccine, he adds.
As a therapeutic vaccine, ImMucin is designed to be given to patients who are already suffering from cancer to help their bodies fight off the disease rather than to prevent the disease in the first place. Multiple myeloma is the second most common hematological malignancy in the U.S., after non-Hodgkin lymphoma.
Dr. Carmon suggests that ImMucin’s therapeutic value lies in treating patients in the early stage of disease relapse, providing a window of opportunity for immunity to be built-up. “In a way, we are attempting to change the paradigm of current cancer treatment, which focuses on patients already in relapse, not just in myeloma but in other cancers as well. Hence, we hope to use ImMucin to prolong the patient’s remission, so the disease will not come back or, at the very least, to delay its return.”
The company also noted that nine of the 15 patients in the latest study had a clinical response to the vaccine. Five patients ended the study with a complete response to treatment and four patients had stable disease, which required no further treatment. Of the six patients with progressive disease, one had demonstrated a significant decrease in the progression rate for a period of time while undergoing treatment.
“These are very encouraging results for a first trial but clearly it is not statistically significant, given the small sample size,” Dr. Carmon notes.
Vaxil now plans to conduct a larger study in multiple myeloma this year and is preparing submissions to the FDA. Dr. Carmon says the trial is expected to have a treatment phase and maintenance phase. “We believe the immune response to the vaccine will not last forever, and we will have to boost immunity in these patients. That will allow us to follow more patients for a longer period of time to see the clinical potential of the vaccine.”
The company also plans to conduct a small study in Israel with ImMucin this year in patients with solid tumors, possibly in breast or lung cancer.
Last September, Vaxil initiated VAXIL-002, a clinical study in Israel to evaluate the long-term safety, quality of life and long-term efficacy of those multiple myeloma patients who were treated with ImMucin in the VAXIL-001 trial and who had a clinical response and did not require further treatment.
Patients enrolled in VAXIL-002 do not receive ImMucin or any other treatment. They will be monitored until the end of 2015 or until the disease returns or progresses to a stage where further treatment is required.
Vaxil also is developing MTBuVax, a therapeutic vaccine for tuberculosis, one of the largest causes of mortality in the developing world. However, over the past few years, there has been an increase in incidence rates in the Western World due to: the low efficacy of the current TB vaccine, BCG; increased global travel; mutation of the TB bacteria to new strains that are resistant to drug treatment; and a strong link of TB with HIV infection.
Dr. Carmon notes that MTBuVax is in preclinical studies and that promising results have been achieved to date. Earlier this year, the company signed a research agreement with the University Santiago de Compostela in Spain to combine the vaccine with the university’s nanoparticle technology to promote a more exact and controlled release.
While the company plans to continue preclinical development, it is searching for a partner for future clinical development.