Sept. 19, 2006 -- A custom-made, experimental vaccine made from a patient's own tumor cells appears to dramatically increase remission time in people with a common form of non-Hodgkin's lymphoma, researchers in Spain report.
Twenty of the 25 patients with follicularparticipating in the study showed an immune response after receiving the vaccination.
All of those responding patients had longer disease-free remissions than would have been expected without the experimental vaccinations. Most are still in remission.
The findings must be confirmed in larger studies. But the hope is that the targeted-vaccine approach will increase overall survival times in patients with the.
"We will see in another five years what happens to these patients, and that should certainly tell us more," Maurizio Bendandi, MD, PhD, tells WebMD.
Teaching the Immune System
The average survival for patients with the most advanced forms of the disease is seven to 10 years.
But despite its typically slow progression, the cancer is not generally curable with conventional treatments.
Chemotherapy, radiotherapy, and even other treatments that enlist the immune system have been shown to improve remission times in patients. But their impact on overall survival remains unclear.
Remission times typically become shorter and shorter with each relapse in such patients.
Researchers have been studying vaccines made from a patient's own tumor cells as a possible treatment strategy for lymphatic cancers for more than a decade.
The idea is that these custom-made vaccines can essentially teach the immune system how to recognize and kill cancerous cells.
The newly reported findings are described in the Sept. 20 issue of the Journal of the National Cancer Institute.
Most Patients Haven't Relapsed
The 25 patients in the study were in their first relapse following initial treatment with a widely used chemotherapy regimen.
All responded to a second course of chemotherapy, and all were also vaccinated periodically with the experimental vaccine over more than two years.
The average time to a second relapse among follicularpatients treated with chemotherapy alone is 13 months.
The average time to relapse in this study has not been reached yet, but is already over 33 months among the 20 patients who responded to the vaccine.
Nineteen of those responding patients had not relapsed at the time the study was published. Three have remained relapse-free for more than four years.
Also, most of the responding patients saw second remissions that were longer than their first. Conversely, second remissions were shorter than the first remissions for the five participants who did not respond to the vaccine, which would normally be the case.
Characterizing the findings from the vaccine study as "persuasive", longtime lymphoma researcher Dan Longo, MD, of the U.S. National Institutes of Health, adds that there are many unanswered questions about the treatment.
First and foremost is whether the vaccination strategy will complement or interfere with the biologic drug Rituxan (rituximab), which works in a similar way by enlisting the immune system to fight .
Rituximab along with chemotherapy is now considered a standard therapy for the treatment of aggressive lymphomas.
"If the observed remissions remain durable, the stage seems set for a head-to-head comparison between rituximab and [the targeted] vaccination as post-remission therapy in patients who achieve an initial chemotherapy-induced complete remission," Longo wrote in an editorial accompanying the study.
"If that comparison reveals a clear winner based on a disease-free survival endpoint, it may be time to consider putting in the effort to conduct a major study assessing overall survival," Longo said.