Expert Explains Role for Newly Approved TKI/mTOR Combo in RCC

Sumanta Kumar Pal, MD

Patients with advanced renal cell carcinoma (RCC) who have progressed on cabozantinib (Cabometyx) and nivolumab (Opdivo), now have a promising new treatment option, says Sumanta Kumar Pal, MD.

“Lenvatinib (Lenvima) plus everolimus (Afinitor) represents something that patients with heavily pretreated disease can potentially be approached with,” says Pal. “If a patient is fit enough to receive this regimen after having progressed on agents such as cabozantinib and nivolumab, it is a reasonable treatment option. It is always beneficial to have additional therapeutic options for these patients.”

The TKI lenvatinib was approved in combination with everolimus, an mTOR inhibitor, in May 2016 as a treatment for patients with advanced RCC following prior antiangiogenic therapy. The approval was based on a phase II trial, known as Study 205, which demonstrated that the combination reduced the risk of progression or death by 63% versus everolimus alone.1,2 Median progression-free survival (PFS) with the combination was 14.6 versus 5.5 months with everolimus (HR, 0.37; 95% CI, 0.22-0.62) and there was a 33% reduction in the risk of death with the combination compared with the monotherapy.

OncLive: How was this pivotal trial designed and what were the key findings?

Can you explain the mechanism of action of lenvatinib? What role does the VEGF pathway play in RCC tumor progression?

What synergy is there between lenvatinib and everolimus?

In terms of toxicity, what should oncologists expect with this combination?

Where does lenvatinib plus everolimus fit into the treatment paradigm, in terms of sequencing?

This combination represents the first FDA-approved TKI and mTOR inhibitor treatment regimen in RCC. To gain more insight on the 2-drug therapy, as well as other updates in RCC, OncLive spoke with Pal, an assistant clinical professor in the Department of Medical Oncology and Therapeutics Research, and co-director of the Kidney Cancer Program at City of Hope.Pal: This was a randomized phase II trial, with between 50 and 60 patients per arm. It included a total of 3 arms; 1 arm had lenvatinib alone, another had everolimus alone, and the third explored the combination. The study identified that lenvatinib with everolimus significantly delayed cancer progression as compared with everolimus alone.We think that the VEGF pathway is very critical throughout the natural history of RCC by promoting blood vessel growth and formation. Lenvatinib goes well beyond that by targeting multiple receptors at the cell surface and, by virtue of this, it possibly has greater antitumor activity than some of the other agents we have been exposed to in the past.Certainly, we see more than we would anticipate with other combinations of drugs. Other combinations of VEGF inhibitors with everolimus have been somewhat disappointing, in terms of the results that they have generated clinically. Here, we have significant efficacy and I would propose reasonable safety; however, it should be used cautiously in patients.This combination will be well known to physicians who have used both VEGF-directed drugs and mTOR inhibitors in the past. Nevertheless, there seems to be some non-overlapping toxicities between the two. Clinicians should be prepared for a greater scope of toxicity.The level of evidence is higher with cabozantinib and nivolumab, as both of those agents were approved on the basis of randomized phase III trials that included many more patients.

What are the biggest challenges that remain in advanced RCC?

In my opinion, the standard second-line treatment should be cabozantinib, because we know the agent led to improvement, not just with PFS and response rate, but also in overall survival (OS), as well. The third-line treatment of choice would be nivolumab, given that this agent has been shown to improve both response rate and OS. Beyond that, perhaps lenvatinib plus everolimus represents a reasonable option. Certainly, the combination is preferred to everolimus alone now.One thing that is critical to keep in mind is that renal cell carcinoma remains an incurable disease. It is a bit of a paradox that we have multiple targeted therapies available in RCC but we do not apply them in a targeted fashion.

A better understanding on which patients will benefit from which targeted therapies would perhaps maximize outcomes. Personally, I believe that broader use of molecular testing is essential for us to gain a better understanding of how to appropriately apply therapies in this disease.

Are there any other studies in this space on the horizon that you are interested in?

At this point in time, we don’t use any molecular testing as the standard of care for patients with metastatic disease, although I would argue that molecular testing does provide certain potential signals that have been well vetted in literature that can predict response to certain drugs.Perhaps the most interesting set of studies on the horizon are those exploring PD-1 inhibitors in the frontline setting. That may shake up the way in which we are currently applying those drugs. I am also excited to see the results of first-line treatment studies examining cabozantinib.* These may potentially shift the paradigm, as well.

*Editor’s note: Since our interview with Pal, Exelixis reported that frontline cabozantinib significantly improved PFS compared with sunitinib (Sutent) in patients with advanced RCC in the phase II CABOSUN trial.

References

1. Motzer R, Hutson T, Glen H, et al. Randomized phase 2 three-arm trial of lenvatinib (LEN), everolimus (EVE), and LNE+EVE in patients (pts) with metastatic renal cell carcinoma (mRCC). J Clin Oncol. 2015;33 (suppl; abstr 4506).
2. Motzer RJ, Hutson TE, Michaelson MD, et al. Lenvatinib, everolimus, and the combination in patients with metastatic renal cell carcinoma: a randomised, phase 2, open-label, multicentre trial. Lancet Oncol. 2015;16(15):1473—1482.