TCR²'s gavo-cel survives a PhI test. Now it's head-first into PhII with a half-dozen partial responses
A T cell biotech has some positive results, and now that the data are out, the biotech is moving forward on its next steps.
TCR² Therapeutics teased results from the Phase I portion of an ongoing Phase I/II study Tuesday, going on a conference call Wednesday to dive more into the details of what ended up happening. The company’s drug candidate, gavo-cel, is being investigated in solid tumors expressing mesothelin, a protein that has been examined as a biomarker in other T cell therapies.
As of Sept. 9, 32 heavily pretreated patients (at least five prior lines) with ovarian cancer, mesothelioma and bile duct cancer received one gavo-cel infusion. In short, all but two of the 30 patients that could be evaluated for efficacy — 93% of patients total — saw their target lesions reduce in size from anywhere between 4% and 80%, the company said.
Additionally, six patients achieved tumor reduction large enough to be considered partial responders. In patients with malignant pleural/peritoneal mesothelioma, the median OS was 11.2 months while the median PFS of 5.6 months.
CEO Garry Menzel tells Endpoints News that the Phase I portion of the study was a dose-escalation part of the study, and eventually was de-escalated after researchers found the highest tolerable dose. That original dose of 500 million cells per square meter was cut down by 80% to only 100 million cells, which is now being used in the Phase II part of the study. The Phase II portion began over the summer, the CEO added, noting that the T cell outfit is still following 12 patients in that Phase I study.
The biotech added an indication for NSCLC, and instead of a monotherapy with just gavo-cel, TCR² is adding immune checkpoint inhibitors to its candidate to be tested as a combination therapy. To that end, the chief executive touted a deal with Bristol Myers Squibb inked last year to use Opdivo and Yervoy alongside gavo-cel.
Menzel said that TCR² will most likely have several opportunities to provide data since it could be done collectively or by reporting data from single cohorts. Menzel also noted that it is still too early to get the FDA involved on what is needed to get to the registrational stage, as that conversation will take place after the Phase II trial reads out and the biotech gets more precise numbers on efficacy.
The new update comes a year after the FDA handed the Cambridge, MA biotech orphan drug designation for its T cell therapy.
Shares of $TCRR went up 11% in early morning trading.
TCR² is not the only company that has been — or had been — looking at mesothelin. Atara Biotherapeutics has been looking at mesothelin in a CAR-T cell therapy program, but ended up pausing the program after a patient death earlier this year. Bayer ended its partnership with Atara as part of the fallout.