The confirmed overall response rate was 42.2% (19/45) in patients who received ilixadencel plus sunitinib and 24.0% (6/25) in patients who received sunitinib monotherapy. reported these results at the ASCO-SITC Immuno-Oncology Symposium.of Uppsala (Sweden) University Hospital,
The complete response rate was 11.1% with ilixadencel plus sunitinib and 4% with sunitinib monotherapy. The confirmed complete response rates were 6.7% and 0%, respectively.
The median duration of response was 7.1 months with ilixadencel plus sunitinib and 2.9 months with sunitinib monotherapy. The median progression-free survival was 11.8 months and 11.0 months, respectively.
There was no difference in median overall survival – a coprimary endpoint – at 18 months, nor was there a difference in progression-free survival at that time. “We do find it interesting that there is a late separation of both [survival] curves like we see in many immunotherapy trials,” Dr. Lindskog said, noting that all five complete responders in the combination therapy arm were alive at 33 months, whereas the single patient with a complete response in the monotherapy group died after 41 months.
“So far, we have 54% versus 37% still alive in the ilixadencel versus sunitinib groups,” Dr. Lindskog said, adding that the observed activity of ilixadencel appears to be driven by responses in patients with intermediate risk.
The overall survival data in the intermediate-risk patients is not mature. The overall survival in poor-risk patients was 11.6 months in the combination group and 9.3 months in the monotherapy group.
participants were adults with a mean age of 62-64 years who were considered surgical candidates. They were enrolled from eight centers in Europe and the United States between April 2014 and January 2017 and randomized 2:1 to the combination and monotherapy arms. In all, 45 patients received their assigned treatment in the combination arm, and 25 patients received their assigned treatment in the monotherapy arm.
Patients in the ilixadencel arm were injected twice, 2 weeks apart, at the primary tumor site using CT guidance. Patients in the monotherapy arm were observed until nephrectomy. Both groups received sunitinib after nephrectomy, which was performed within 6 weeks, and all were followed for 18 months.
Treatment was well tolerated. Ilixadencel did not add any clinically meaningful treatment-related grade 3-4 adverse events or serious adverse events, Dr. Lindskog said. He noted that the most common ilixadencel-related adverse event was uncomplicated pyrexia.
There were no signs of induced autoimmunity, and although 57% of patients in the combination therapy group developed ilixadencel-specific alloantibodies, this had no relationship to responses, Dr. Lindskog said.
“From this phase 2 study, we have confirmed the feasibility and safety of ilixadencel and sunitinib combined in newly diagnosed synchronous metastatic renal cell carcinoma patients,” he said.
He added that longer follow-up is needed to understand the late divergence in survival curves between the groups. Survival follow-up will continue for 5 years.
This study was funded by Immunicum. Dr. Lindskog disclosed relationships with Pfizer, Bristol-Myers Squibb, and Ipsen.
SOURCE: Lindskog M et al. ASCO-SITC 2020, .