By Grant Zeng, CFA
Advaxis Updates Phase II Results for ADXS-HPV at ASCO
On June 2, 2013 at the ASCO meeting, Advaxis (OTC BB:ADXS) reported final 12 month overall survival and additional data for ADXS-HPV (Lm-LLO-E7-15) from a randomized Phase II study evaluating the safety and efficacy of ADXS-HPV +/- cisplatin in patients with recurrent cervical cancer.
As a reminder, ADXS initiated the Phase II study in November 2010 in India in 110 Patients with recurrent or refractory cervical cancer. This study is being conducted at 22 sites in India. All patients randomized to the trial have been previously treated with chemotherapy, radiotherapy or both, and their cancer has progressed subsequent to treatment and has been confirmed by CT or radiologic scan.
Patients are randomized into 2 groups of 55 patients receiving: ADXS-HPV or ADXS-HPV + cisplatin (40 mg/m2, weekly x5). Patients got either 3 doses of ADXS-HPV at 1 x 109 CFU or 4 doses of ADXS-HPV at 1 x 109 CFU with cisplatin chemotherapy. Naprosyn and oral promethazine are given as premedications and a course of ampicillin is given 72h after infusion thereby clearing any residual vector. Patients receive CT scans at baseline and Days 84, 184, 273, 365 and 545. The primary endpoint is 12 month survival.
Enrollment was completed in May 2012 and preliminary results were presented at 2012 ASCO and GOG meeting in the summer of 2012 and at the Society for Immunotherapy of Cancer (SITC) 27th Annual Meeting in October 2012.
As of May 17, 2013, 110 patients have received 264 doses of ADXS-HPV (ADXS11-001). Final 12-month overall survival is 36% (39/110) with a (current) 18 month survival of 22% (16/73). This compares to 33% and 17%, respectively, at the last update and are the best results yet reported for this study.
These data are comparable to the results for the landmark 2004 Moore Phase III study of cisplatin alone and cisplatin plus paclitaxel in recurrent cervical cancer patients with the same initial performance (health) status (0-2). In that study, 12 month survival was presented as 35% for cisplatin alone and 32% for the combination and 18 month survival was presented as 20% for combination therapy and 12% for cisplatin, alone.
Median overall survival was approximately 8.5 months. Those patients who have completed the study will continue to be followed for survival. Survival results were not significantly different between groups who had previous therapy of radiation, alone, chemotherapy, alone, or a combination of both.
The tumor response rate was 11% with 6 complete responses and 6 partial responses/110 patients and was similar in both treatment groups per RECIST 1.1 criteria. Stable disease >3 months was observed in 33 additional patients, for a disease control rate of 41% (45/110). Average duration of response after 12 month minimum follow-up was 10.5 months for both treatment groups. In those patients treated with ADXS-HPV alone who had stable disease, the average duration of response was 6 months compared to 4.1 months in patients treated with ADXS-HPV plus cisplatin. Activity was observed against all high risk human papillomavirus (HPV) strains detected, including 16, 18, 31, 33, and 45.
Subset analyses showed that the addition of cisplatin to ADXS-HPV did not significantly improve survival or tumor response in this study; and survival and tumor response were equally strong in patients with aggressive disease (defined as recurrence ≤2 years from initial diagnosis) versus non-aggressive disease (defined as recurrence >2 years from initial diagnosis).
The tolerability of ADXS-HPV continues to compare favorably with single agent and combination chemotherapies active in this disease setting. 41% (45/110) of patients experienced 104 mild-moderate Grade 1-2 adverse events and 2% (2/110) of patients experienced a Grade 3 serious adverse event. This compares to published treatment-related serious adverse event rates of 100%-400% in studies evaluating a range of chemotherapy regimens for cervical cancer, including the Moore study and studies conducted by the Gynecologic Oncology Group (GOG) of the National Cancer Institute (NCI).
Our Takeaways From the Updated Results
The data presented at the ASCO are very encouraging.
After 110 patients and 264 doses, the safety data is encouraging. ADXS-HPV continues to demonstrate a well-tolerated and manageable safety profile with 32% of patients reporting Grade 1 or 2 transient, flu-like symptoms that self-resolve or respond to symptomatic treatment. Less than 2% of patients reported serious adverse events associated with ADXS-HPV. Published studies on chemotherapy treated patients like these show 100% of patients experiencing severe adverse events, usually multiple times. Serious adverse events result in death, are life-threatening, cause significant disability or require inpatient hospitalization.
Great efficacy has been observed which are very promising. Compared to GOG historical one year survival of 5%, ADXS-HPV has achieved 36% one year survival rate. This is a huge improvement. Other literature data showed that generally, recurrent cervical cancer has a poor 1-year survival rate of 15% and a 5-year survival rate of 3-13%. ADXS-HPV’s 36% one year survival rate is also a 100% improvement. Further investigation is warranted. 18 month survival also reached 22%.
ADXS-HPV appears to be emerging as an active agent in recurrent/refractory cervical cancer with significantly less toxicity than chemotherapy.
The positive ADXS-HPV data may trigger partnership talks for Advaxis.
ADXS-HPV for cervical cancer is the Company’s current focus. Advaxis plans to conduct new short term clinical trials to support its partnership talks as well as the planned Phase III trial of ADXS-HPV.
A copy of the latest research report can be downloaded here >> Advaxis Report
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