The overall survival of individuals with follicular lymphoma has recently increased according to several recent research reports, which means that novel clinical measurements other than survival are needed for studies examining new treatments.
The improvement in survival may be a consequence of better medications such as monoclonal antibodies as well as treatments for relapsed and refractory disease.
A report from Stanford University published in the journal Blood examined overall survival of follicular lymphoma patients in four different eras between 1960-2003. The eras were labeled according to the types of chemotherapy that were available at the time. Era 1 was defined as pre-anthracycline (1960-1975); era 2, anthracycline (1976-1986); era 3, aggressive chemotherapy/purine analogs (1987-1996); and era 4, rituximab (1997-2003).
Overall survival was calculated as a middle-value (median) of 13.6 years for all of the eras studied. According to the research report the overall survival “improved from 11 years in eras 1 and 2 to 18.4 years in era 3.” Era 4 could not yet be calculated. The researchers noted that “Several factors, including better supportive care and effective therapies for relapsed disease, are likely responsible for this improvement.”
Because of the success of treatments at prolonging overall survival, this measurement may no longer be a useful endpoint for assessing the usefulness of new therapies. Researchers are therefore searching for new endpoints for clinical studies of follicular lymphoma treatment to replace overall survival.
Progression-free survival (PFS)–how long a person lives with follicular lymphoma without getting worse–has been adopted as another endpoint that may be used in clinical trials. A downside of this measurement is that a long period of time is needed for scientists to be able to assess PFS accurately. For example, R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) has a PFS rate of 5 to 8 years according to several research studies.
At the 2015 American Society of Clinical Oncology (ASCO) Annual Meeting, researchers presented the Follicular Lymphoma Analysis of Surrogacy Hypothesis (FLASH) results. In this study the investigators used the measurement of complete remission at 30 months from treatment onset (CR30 for short) instead of long-term PFS.
According to the scientists this may become a widely used new endpoint for studies of follicular lymphoma, based on its high reliability.
A separate study out of the University of Rochester, published in the Journal of Clinical Oncology, examined early disease progression (within the first two years) in people with follicular lymphoma who had received R-CHOP as their first treatment. Researchers found that people with early disease progression did have overall reduced long-term survival, suggesting that early progression may also be a good endpoint for follicular lymphoma trials.
The success of treatments for follicular lymphoma has created an enviable new problem: finding measurements other than survival for treatment success. Hopefully the trend toward improved therpies of this type of cancer will continue into the future.