How drug repurposing is paving the way for better chordoma treatments

While new drugs may ultimately be required to cure chordoma, the fastest path to better treatment options in the near-term for patients in need is through existing drugs. To that end, our Drug Repurposing Initiative is systematically identifying these treatment options, with the goal of rapidly initiating new, well-justified clinical trials.

The centerpiece of our Drug Repurposing Initiative is our Drug Screening Program (DSP), an industrial-scale effort to predict whether existing drugs could work against this disease by testing them in the laboratory in chordoma cell lines and mouse models. The DSP is a critical piece of infrastructure shared by the entire chordoma research community, which has significantly lowered the barriers to advancing promising therapeutic concepts by enabling any scientist or company to generate preclinical data in a fraction of the time and at a fraction of the cost of running experiments themselves.

Experiments through our DSP are helping determine which approaches are most likely to benefit patients. Not every drug that shows some promise should be advanced to a clinical trial; this is particularly important for a rare cancer like chordoma where funding is constrained and the patient population is small. Our DSP enables drugs to be compared head to head, so that only the most promising candidates are taken forward.

Recently, several important milestones have been reached through our Drug Repurposing Initiative, including:

• Five clinical trials have been initiated or planned based on DSP results: trials are currently underway testing palbociclib, afatinib, and pemetrexed; enrollment for a trial testing cetuximab is about to begin; and a trial to test selinexor is being planned.
  

• This year, our grantees at the Broad Institute of Harvard and MIT completed their comprehensive effort to test nearly all existing drugs against chordoma cells: more than 6,000 drugs have been evaluated, including all FDA-approved drugs plus most drugs ever to enter clinical trials for any condition. Several drugs of interest were identified in the course of this effort which are now being evaluated further through the DSP.

• The drugs identified by the Broad researchers, as well as other promising drugs and drug combinations nominated by additional research groups and companies, have been moving through our DSP with increasing speed. Over the last 18 months, 31 promising treatment approaches have been evaluated in chordoma mouse models. Notably, this is nearly equivalent to the number of drugs that had ever previously been tested in chordoma mouse models, and is more than have ever been tested for most other cancers of similar rarity.

• Recent experiments in our DSP have identified five new treatment approaches capable of significantly slowing or stopping chordoma tumor growth in mice. We hope that one or more of these treatments become positioned to move into Phase 2 clinical trials for chordoma in the next year. In the meantime, some of these therapies are available to chordoma patients through an off-label prescription or through ongoing Phase 1 trials.

• In the spirit of rapid data sharing, in the last few months we’ve publicly deposited all non-confidential data from our in vivo Drug Screening Program in Figshare to share our observations and prompt further research.

In the next several months, testing will be completed for most of the therapies mentioned above which are showing significant preclinical efficacy. Data will be reviewed by the Foundation’s Medical and Scientific Advisory Boards this spring to determine whether clinical trials testing these drugs in chordoma patients are justified. And there are 20 drugs and drug combinations for which evaluation is ongoing in mouse models, four more in the queue for testing, and more concepts being proposed and vetted on an ongoing basis.

Looking ahead, our work in this area will increasingly focus on identifying drugs and drug combinations that not only stop or slow tumor growth but actually drive tumor regressions. We’re also working to develop a mouse model suitable for testing certain types of immunotherapies that could be relevant to chordoma, and in 2022, we’ll be able to evaluate promising immunotherapies in our DSP for the very first time.

These experiments are moving at an exciting pace, and our expanding capabilities — including increased organizational capacity — will help us evaluate well-justified drugs and drug combinations even more quickly and efficiently going forward. We’re grateful for our supporters, who are helping us drive drug repurposing faster, more efficiently, and more thoroughly than for almost any other rare cancer.