By BISHAL GYAWALI, MD
Keynote speech on the JAVELIN not going far enough to improve survival
The treatment landscape for metastatic renal-cell carcinoma has changed dramatically with the introduction of immunotherapies. Unfortunately though, we are promoting combinations over single agents without having much idea of added benefit of each drug. This is an important issue because when we combine two drugs, the only thing we are certain of are the added toxicities. PD-1 inhibitor nivolumab had improved OS when given in second line, however nivolumab was tested in combination with ipilimumab (not as a nivolumab monotherapy) in the first line trial. Now, pembrolizumab and avelumab have followed suit, although their combination partner was axitinib – a VEGF inhibitor. The control arm was sunitinib for both of the trials of pembrolizumab plus axitinib (KEYNOTE 426) and avelumab plus axitinib (Javelin 101). This is a little surprising because we are testing A B versus C, where both A and B haven’t been approved for the given setting – axitinib was approved for RCC in second line. Both these combinations improved PFS versus sunitinib but only the pembrolizumab combination has shown improved OS. However, I have doubts about the contribution of axitinib to these results. What would the outcome be if pembrolizumab alone is followed by sunitinib in second line? It is important to note that only one third of patients who discontinued sunitinib received PD-1 inhibitor subsequently in the KEYNOTE 426 trial. The important question for patients and clinicians would be to consider a survival difference had most of these patients received a PD-1 inhibitor subsequently. As for avelumab, the JAVELIN trial hasn’t reached as far as pembrolizumab and nivolumab have reached: The OS benchmark – so let’s reserve this combination until we see that benefit.
Have we successfully landed on the COMET?
We should remember that this combo-mania with PD-1/PD-L1 inhibitors may also backfire. Previously, the RCTs of nivolumab and pembrolizumab combos were halted in multiple myeloma for higher deaths in the combo arms. Another RCT IMblaze 370 also reports that atezolizumab, alone or in combination with cobimetinib, failed to improve survival versus regorafenib in patients with metastatic colorectal cancer. This time again A B failed versus C although C in itself is a drug with very marginal benefits in this setting. Also, I don’t understand testing A plus B combo when both A and B are unapproved for the disease.