Drugs to Treat ROS1+ Cancer

 

” …although pemetrexed-based chemotherapy has activity in ROS1-positive NSCLC, it is almost certainly less efficacious than ROS1-targeted therapies. Taken together, the single-arm data with crizotinib, entrectinib, and now ceritinib support upfront therapy with ROS1 TKIs in patients with advanced ROS1-positive NSCLC.”
–Dagogo-Jack and Shaw, Journal of Clinical Oncology, May 2017

The drugs listed on this page are all targeted therapies, not chemotherapy. ROS1 targeted therapies go into every cell in the body and bind to the ROS1 protein (specifically, tyrosine kinase receptors), which is coded by the ROS1 gene. This protein is not active in typical adult cells, but in cells with oncogenic ROS1 fusions, the protein makes the cell act like cancer. Once the drug binds to the protein, the drug turns off the protein’s signaling in the cell, which is why these drugs are called “tyrosine kinase inhibitors,” or TKIs. Because they only inhibit cells with certain genomic alterations (instead of acting on all fast-growing cells as chemo does), TKIs tend to have fewer side effects than chemo. However, TKIs only inhibit the cancer cells, so they cannot cure it. Most all patients treated with TKIs find their cancer eventually starts to grow again because the cancer cells develop “resistance mutations.”

These drugs are in various phases of development and testing against ROS1+ cancers.  Two drugs (crizotinib and entrectinib) has received approval from some regulatory agencies for treatment of ROS1+ cancer–their effectiveness in the body is comparable, but only entrectinib can treat the brain effectively.  Some other drugs are approved for treatment of other cancers, and so may be accessible off-label even though they are not approved for ROS1+ cancers.

Due to the small population of ROS1+ cancer patients (about 1% of non-small cell lung cancers, and a similar fraction of about a dozen other cancers), it’s unlikely a phase III clinical trial comparing different treatment options will happen. The data below comes from Phase 1/2 clinical trials and other sources.

Note that many ROS1 experts believe patients on TKIs should not take “drug holidays” if the drug is effective and the patient is tolerating the drug well.

Summary of ROS1 TKIs

crizotinib (Xalkori) — Pfizer

Crizotinib has been the standard of care for metastatic ROS1+ non-small cell lung cancer (NSCLC) in the USA and other countries. In clinical trials, crizotinib was shown to be effective for 70-80% of patients. Some patients achieved no evidence of disease on the drug.  The average progression-free survival was 19.2 months, and some patients have a response lasting for years. Crizotinib is effective even in patients previously treated with chemotherapy. Pfizer offers financial assistance to help pay for crizotinib for some patients. One case study suggests patients who develop certain lorlatinib resistance mutations might be resensitized to crizotinib.

Crizotinib is approved by US FDA, Japan, Taiwan, Israel, and Australia, and has marketing authorization in the European Union and United Kingdom for treating ROS1+ NSCLC.  It is also available via clinical trial in other countries and for ROS1+ cancers other than NSCLC via Clinical Trials (and expanded access for those who cannot swallow crizotinib tablets).

entrectinib (Rozlytrek, RXDX-101) — Roche (was Ignyta)

Entrectinib may become the new standard of care for ROS1+ NSCLC due to its ability to effectively treat the brain (which crizotinib doesn’t do for most patients).  The drug was approved by the US FDA for ROS1+ NSCLC (also for NTRK+ solid tumors) on August 15, 2019.
The entrectinib STRTRK-2 trial was a basket design, which allowed  patients with any solid tumor  to enroll if their tumor tests positive for ALK, ROS1, or TRK rearrangements.  Ignyta recently published an update on the trial and showed promising results for ROS1+ non-small cell lung cancer (NSCLC) patients who have not taken other targeted therapies, especially those patients who have brain metastases. Entrectinib is not an effective treatment for ROS1+ cancers that have progressed on crizotinib. However, patients who cancer is controlled by crizotinib in the body were allowed to enroll in the trial if they developed brain mets. The clinical trial stopped enrolling ROS1+ patients in January 2018 but the trial continues for patients with other types of ROS1+ cancer.

In a pooled analysis of Phase I and Phase II trials presented at WCLC 2018, entrectinib’s objective response rate was 77.4% for the 53 patients evaluable for response, and the median duration of response was 24.6 months. Among 23 patients (43.4%) enrolled in the trial with evaluable brain metastases, the intracranial response rate was 55%. The duration of intracranial response was 12.9 months. (Data was not presented on ROS1+ cancers other than NSCLC because too few patients with those cancers participated in the trial.)

Entrectinib received US FDA Orphan Drug Designation for Treatment of Molecularly Defined Subsets of NSCLC (5-Feb-2015) and was granted breakthrough therapy designation by US FDA for NTRK fusion-positive, locally advanced or metastatic solid tumors (15-May-2017).  In a 2017 communication to shareholders, Ignyta indicated it is pursuing approval of entrectinib for ROS1+ cancers.

Roche agreed to acquired Ignyta at the end of 2017.

ceritinib (Zykadia, LDK378) — Novartis

Studies found ceritinib demonstrated potent clinical activity (including treating the brain) in ROS1+ NSCLC patients who had previously received platinum-based chemotherapy. In preclinical studies, ceritinib is unable to overcome most ROS1 resistance mutations, including ROS1 G2032R. It has more severe side effects than crizotinib for many patients.  Ceritinib is approved for first line treatment of ALK+ metastatic non-small cell lung cancer in the USA and several other countries. Some ROS1+ patients are able to have it covered by insurance as an off-label prescription.

lorlatinib (PF-06463922) — Pfizer

A Phase 2 clinical trial has shown Lorlatinib (a tyrosine kinase inhibitor) is effective in the majority of ROS1+ non-small cell lung cancer patients, and treats cancer in the brain as well as the body. It has the potential to overcome certain resistance mutations that develop during treatment with crizotinib, and is well tolerated.

Lorlatinib was granted US FDA Breakthrough Therapy Designation for ALK+ NSCLC patients previously treated with TKIs on 27-Apr-2017. Lorlatinib was approved for ALK+ NSCLC in Japan in September 2018, and the FDA approved lorlatinib for second- or third-line treatment of ALK+ NSCLC on November 2, 2018. Lorlatinib is available off label for ROS1+ NSCLC, and some US ROS1 NSCLC patients have been able to obtain insurance coverage with assistance of their oncologists.  It is available to ROS1+ NSCLC patients in other countries via expanded access and compassionate use.

The status of lorlatinib FDA filings for ROS1+ NSCLC is unknown. Despite this, the 21-Nov-2018 NCCN Guidelines for NSCLC added lorlatinib as a treatment option for ROS1+ metastatic NSCLC after progression on crizotinib or ceritinib.

repotrectinib (TPX-0005) — TP Therapeutics

The TPX-0005 Phase 1/2 clinical trial opened in March 2017 for patients with advanced solid tumors harboring ALK, ROS1, or NTRK1-3 rearrangements in the US and South Korea. This drug was designed by Dr. Jean Cui, the lead chemist for the Pfizer team that designed crizotinib and lorlatinib.  Preclinical data shows is it a potent inhibitor of ROS1+ cancer. It received FDA orphan drug designation on June 27, 2017 for “treatment of non-small cell lung adenocarcinomas harboring ALK, ROS1, or NTRK oncogenic rearrangements.” Preliminary phase 1 trial results were announced at ASCO 2018, and show the drug can treat brain mets. Phase 2 sites are enrolling in several countries.

cabozantinib (Cometriz, Cabometyx) — Exelixis

Cabozantinib is US FDA approved for metastatic medullary thyroid cancer (as Cometriq) and renal cell carcinoma (as Cabometyx). It has shown ability to overcome crizotinib resistance in ROS1+ cancer in early studies, but the required dosage makes the drug difficult to tolerate for long.  Memorial Sloan Kettering has been running a Phase 2 clinical trial since 2012 to explore the effectiveness of cabozantinib for ROS1+ non-small cell lung cancer.

AB106 — AnHeart Therapeutics (was DS-6051b by Daiichi Sankyo)

The Phase 1 DS-6051b clinical trial opened in 2014 in both the USA and Japan, but was slow to accrue in the US. Phase 1 data for the Japanese trial was published in May 2018. In December 2018 Daiichi Sankyo granted AnHeart Therapeutics worldwide exclusive rights for the development, manufacturing and commercialization of DS-6051.  The drug was renamed AB106. After the Phase I trial, AnHeart will assume responsibility for further clinical development.

Safety and pharmacokinetics of DS-6051b in Japanese patients with non-small cell lung cancer harboring ROS1 fusions: a phase I study

ensartinib (X-396) — Xcovery Holding Company

Preclinical data shows ensartinib has activity against ROS1+ cancer. It is in a clinical trial for pediatric ROS1+ patients.

DRUGS WITH NO ROS1 CLINICAL TRIALS

brigatinib (Alunbrig, AP26113) — Takeda Oncology (was Ariad Pharmaceuticals)

Preclinical data indicated brigatinib inhibits ROS1+ cancer. A small study of three patients with ROS1+ NSCLC showed 1 partial response, 1 with stable disease, and 1 with progressive disease. It’s unlikely a larger clinical trial will be run for ROS1+ cancers. Brigatinib was approved by US FDA for ALK+ NSCLC patients who have progressed on or are intolerant to crizotinib (28-Apr-2017). Some ROS1ders with cancers other than NSCLC have anecdotally reported disappointing results on brigatinib.

foretinib (GSK1363089) — GlaxoSmithKline

Preliminary research suggested foretinib is a potent inhibitor of ROS1+ cancer. However, in 2015 GlaxoSmithKline withdrew the NSCLC clinical trial of foretinib prior to enrollment because they stopped developing the drug.

alectinib (Alecensa, CH5424802, RO5424802) — Genentech

“Notably, the ALK inhibitor, alectinib, does not inhibit ROS1 at all, so should never be used in ROS1-positive NSCLC.”
Dr. Alice Shaw, interview in Cancer Therapy Advisor, June 29, 2017

IMMUNOTHERAPY for ROS1 

At present, consensus among ROS1 experts seems to be that TKIs should be used first line in ROS1 patients, rather than single agent immune checkpoint inhibitors (ICIs), even though PD-L1 tests high.  Some reasons cited by experts for this are:

  1. Several studies (such as the ImmunoTarget trial) found patients whose cancers had driving oncogenes had poorer results on first-line ICIs than on first-line TKIs. (Progression free survival was significantly worse in the ImmunoTarget trial for patients with EGFR, ALK, ROS1, and RET compared to other oncogenic drivers.)
  2. First line ICIs in some lung cancer patients has caused accelerated cancer progression (hyperprogression).
  3. First line ICIs in patients with driving oncogenes seems to be associated with reduced effectiveness of subsequent TKIs.
  4. Side effects of first-line ICIs (such as pneumonitis) can make patients ineligible to take TKIs as a second-line treatment, or cause increased toxicities on subsequent TKIs.

The jury’s still out on whether and when ICI-chemo or TKI-ICI combinations might be useful for ROS1 patients.  Potential toxicity of a combination versus a TKI must be considered when making treatment decisions– a Phase I/2 clinical trial for crizotinib plus nivolumab in ALK+ NSCLC was discontinued due to toxicity.

last update 16-Nov-2019
Please send corrections and updates (ROS1-related press releases, journal articles, and conference posters) to ros1cancer.patient@gmail.com.