Response and survival
In the nivolumab monotherapy arm, 50% of patients (n = 7) had a volumetric response, and 8% (n = 1) had a pathologic complete response.
In the nivolumab-ipilimumab arm, 53% of patients (n = 8) had a volumetric response, and 20% (n = 3) had a pathologic complete response.
“In general, we found that our response metrics were concordant; that is, patients with volumetric responses tended more frequently to have pathologic responses,” Dr. Schoenfeld said. “There were a couple notable cases where there were volumetric increases and significant pathologic responses.”
To identify factors associated with response, Dr. Schoenfeld and colleagues performed correlative multiplex immunofluorescence on 21 patient specimens prior to treatment.
“We did not identify any differences in baseline levels of PD-L1 expression in tumor cells between the two arms,” Dr. Schoenfeld noted. “We found that CD4-positive T cells in the pretreatment specimens correlated with pathologic response [P = .016]. Interestingly, this association was only significant in patients treated with nivo-ipi [P = .008] but not nivolumab alone [P = .83].”
Ten patients went on to receive radiation, and nine received chemoradiation. One patient presented to the operating room but did not undergo surgery because he was thought to require total glossectomy. This patient received chemoradiotherapy, achieved a complete response, and is still disease free after more than 3 years of follow-up.
The median follow-up for the entire cohort was 14 months. At 12 months, the progression-free survival rate was 85%, and the overall survival rate was 89%.
Dr. Schoenfeld noted that this study was not powered to assess survival or to directly compare nivolumab monotherapy and nivolumab plus ipilimumab.
‘Encouraging’ results, but what’s next?
“We were very encouraged by the toxicity data ... [and] the impressive pathologic responses in both arms, but particularly in the nivo-ipi arm,” Dr. Schoenfeld said. “I think the real question is, ‘Does this translate into a significant progression-free or overall survival advantage?’ So I think that would be something worthy of further study.”
“These results are encouraging for management of patients with oral cavity cancers who remain at high risk for recurrence with the current standard of care but will need validation in larger prospective studies,” Dr. Sehgal noted. “Multiple clinical trials are currently ongoing to evaluate the role of neoadjuvant immunotherapy for disease-specific outcomes, notable being phase 2 NCT02296684 and phase 3 KEYNOTE-689 (NCT03765918) with pembrolizumab and phase 3 IMSTAR-HN (NCT03700905) with nivolumab alone or along with ipilimumab.”
The current study was funded by Bristol-Myers Squibb. Dr. Schoenfeld disclosed relationships with Bristol-Myers Squibb and other companies. Dr. Sehgal had no relevant conflicts to disclose.
SOURCE: Schoenfeld J et al. Head and Neck Cancers Symposium 2020, Abstract 1.