Aridis nabs pharma veteran as ex-CMO leaves for 'personal reasons' after drug flop

S. aureus infection
Micro cap anti-infective biotech Aridis Pharmaceuticals has gained a new chief medical officer. (CDC/Matthew Arduino/Janice Haney Carr)

Micro cap anti-infective biotech Aridis Pharmaceuticals has gained a new chief medical officer in the form of former Takeda Vaccines exec Paul Mendelman, M.D.

Mendelman, who for now is CMO on an interim basis, takes over from Wolfgang Dummer, who has hit the exit for “personal reasons,” the biotech said, but gave no extra information nor a departing quote (which typically would be given out in these sort of press releases).

Drummer became Aridis' CMO just 18 months ago, coming off a stint as VP of clinical development at rare disease specialist BioMarin; before this, he spent 11 years over at Genentech.

This comes a month or so after the company announced the failure of a key midstage drug: AR-105, which had been fast-tracked by the FDA, flopped in a phase 2 last month when it failed to hit the primary endpoint of demonstrating superiority in clinical cure rates after three weeks compared to placebo.

The test was in ventilator-associated pneumonia caused by gram-negative Pseudomonas aeruginosa.

It also said in a Securities and Exchange Commission form Sept. 3 there was a “statistically significant imbalance in all-cause mortality, as well as serious adverse event, or SAE, rates between the treatment groups that favored placebo” and that it would no longer “allocate further resources” for the drug.

Aridis' lead candidate, AR-301, now in phase 3 is a brighter light and is being developed as an add-on to standard-of-care antibiotic treatments for hospital-acquired or ventilator-associated pneumonia infections, or HAP/VAP, caused by the Staphylococcus aureus bacteria, including MRSA strains.

AR-301 works by targeting the toxins secreted by S. aureus—binding to them and preventing them from breaking down immune cells and lung tissue—to complement the bacteria-killing properties of conventional antibiotics.

It has received a fast-track designation from the FDA as well as orphan status in the EU.

The company is also aiming for the Chinese market through a joint venture with Shenzhen Hepalink Pharmaceutical Group set up last February. The jointly owned subsidiary will conduct clinical trials in the country, with submissions planned for the China Food and Drug Administration.

The unique mechanism of action in its platform may slow the progression of a pneumonia infection and may be useful against S. aureus infections at surgical sites, in the bloodstream, in diabetic ulcers or in skin or other soft tissues. The monoclonal antibody was discovered by screening B-cell lymphocytes from a patient with an S. aureus infection.

While a completed phase 2a trial last year showed decreases in the time treated patients remained intubated, when it came to assessing whether a patient’s infection was cured, based on the sole judgment of the investigator, there was no statistically significant difference between the addition of AR-301 and standard of care alone, with a high overall cure rate.

However, the company said the results “suggest AR-301 may help cure more infections faster” while reducing the patient’s time under mechanical ventilation and overall duration of hospital stay.

The Californian company, which has a market cap of just $53 million and has seen its shares halved in the past month, was founded all the way back in 2003. A decade later, Aridis acquired six anti-infective immunotherapies and its discovery platform from Switzerland-based Kenta Biotech. Then, in 2018, it got off a small IPO worth $26 million.

“It is a pleasure to welcome Dr. Mendelman, a recognized leader in the development of new treatments for infectious diseases to the Aridis team. His expertise comes at a critical juncture for the company given we are advancing multiple clinical programs, including our lead Phase 3 antibody program, AR-301, which can benefit from additional infectious disease expertise particularly in critical care (ICU) settings,” said Vu Truong, Ph.D., the biotech’s CEO.