Longevity Acquisition Corporation announced that on February 3, 2021, 4D pharma plc, a pharmaceutical company leading the development of Live Biotherapeutic products ("LBPs") - a novel class of drug derived from the microbiome, and a business combination target of LOAC, has announced progress on activities in its development program for lead immuno-oncology single strain Live Biotherapeutic candidate MRx0518. MRx0518 is in an ongoing Phase I/II clinical trial in combination with immune checkpoint inhibitor (ICI) Keytruda® (pembrolizumab), MSD's anti-PD-1 therapy, in patients with advanced malignancies who have previously progressed on ICI therapy. This study is comprised of two parts - Part A, an initial safety phase assessing dose-limiting toxicities of the combination, and the Part B cohort expansion phase to assess clinical benefit in addition to safety.

In May 2020 the successful completion of Part A and initiation of Part B was announced. 24 additional patients across five active US sites have now been treated in Part B of this ongoing study. The safety review following the first Part B cohort of 10 renal cell carcinoma (RCC) patients has been completed indicating no dose limiting toxicities.

A total of 12 patients with RCC, nine patients with non-small cell lung cancer (NSCLC) and three bladder cancer patients have been enrolled in Part B to date. Recruitment will continue up to a total of 30 patients in each of these indications. Target tumor reductions in Part B patients have been observed as patients reach the first scheduled restaging timepoint (nine weeks).

These include the first signals of anti-tumor activity for the combination in bladder cancer, adding to the previously reported activity in RCC and NSCLC in patients in Part A. Three Part A patients with RCC and NSCLC that were previously reported to have experienced clinical benefit continue on the study. Two of these patients have now been treated for over 18 months and have had further target tumor reductions or extended disease control since the last update. Efficacy of the combination continues to be evaluated on an ongoing basis.

Following the positive results of Part A in RCC and NSCLC, the new tumor cohorts added to Part B of the study are now open to recruitment. Patients with advanced malignancies resistant to ICI therapy, including triple-negative breast cancer, head and neck squamous cell carcinoma and microsatellite instability-high/mismatch repair deficient cancers, are now eligible for inclusion. Enrolment for the trial is expected to complete in Fourth Quarter 2021.