Time to Progression (TTP)

Time to Progression (TTP) measures the duration from starting treatment or enrollment in a clinical trial until the cancer worsens or progresses. Unlike progression-free survival (PFS), TTP focuses solely on disease progression and does not account for deaths from other causes. 

You may see TTP in some important clinical trials in myeloma, but it is important to know that although it's an informative value, the FDA hasn't recognized it yet as a surrogate endpoint, meaning that no new treatment will be approved based on this endpoint data.

Duration of Response (DoR)

Duration of Response (DoR) in blood cancer clinical trials refers to the length of time that a patient’s cancer remains under control after achieving a complete or partial response to treatment. It measures how long the patient continues to experience the benefits of the therapy without the cancer worsening or relapsing after the initial response.

For example, if a patient responds to treatment and their myeloma cells decrease or disappear (complete response), DoR tracks how long that response lasts before the disease appears again (if it does). 

In blood cancers like multiple myeloma, DoR is an important endpoint because it provides insight into the durability of the treatment's effectiveness. 

While the overall response rate (ORR) shows how many patients respond to the therapy, DoR tells us how long those responses last, helping to evaluate the long-term benefit of the treatment.

Clinical Benefit Rate (CBR) 

This endpoint reflects the proportion of patients who achieve a significant clinical response, including stable disease, partial response, or better.

While you may see it in publications of clinical trial data, it’s not one of the more important clinical trial endpoints to be familiar with.