Olema Oncology Sees Early Hope As Cancer Drug Shows Tumor Shrinkage In Phase 1 Study

• Nearly two-thirds of evaluable patients experienced tumor shrinkage, with responses seen across multiple cancer types.
• OP-3136 showed a clean safety profile with no dose-limiting toxicities or treatment-related discontinuations.
• Side effects were mostly mild to moderate, with tolerability maintained even at higher dose levels across the study population.

Shares of Olema Pharmaceuticals (OLMA) rose in pre-market trading on Friday after the company reported preliminary Phase 1 clinical data for OP-3136, a potent lysine acetyltransferase 6 (KAT6) inhibitor. 

OP-3136 is a novel oral drug that selectively inhibits KAT6, an epigenetic target linked to breast and other cancers.

Promising Signals In Early Clinical Study

Olema Oncology said early Phase 1 results for OP-3136 showed the drug “demonstrated acceptable tolerability and promising anti-tumor activity as a monotherapy” across multiple dose levels in advanced solid tumors.

Sean P. Bohen, president and CEO of Olema Oncology, said shrinkage in tumor size was “observed in over two-thirds of evaluable patients,” along with evidence of target engagement. He added that these findings support continued development of OP-3136, “particularly in combination with palazestrant in metastatic breast cancer.”

The Phase 1 study is testing OP-3136 through dose escalation and expansion in patients with advanced ER+/HER2- breast cancer, metastatic prostate cancer, and non-small cell lung cancer. 

The drug is being given once daily in 28-day cycles across doses ranging from two mg to 45 mg. As of the March 2026 data cut-off, 32 heavily pretreated patients who had stopped responding to standard treatments were enrolled.

Safety, Tolerability, Efficacy

OP-3136 was generally well tolerated, with no dose-limiting toxicities observed across the evaluated daily dose range up to 45 mg per day orally. Most side effects were mild to moderate, and no treatment discontinuations were reported due to adverse events. The most common side effects included taste changes, anemia, and neutropenia.

Among evaluable patients, tumor shrinkage was seen in 13 out of 19. Many patients remain on treatment. The longest treatment duration was 62 weeks.

OP-3136 showed predictable, dose-related exposure in the body. At doses of 6 mg or higher, drug levels met or exceeded the efficacy targets.

The data will be presented on May 30 at the ASCO Annual Meeting in Chicago.

What Retail Thinks About OLMA Stock

On Stocktwits, retail sentiment turned “extremely bullish” from “bearish” a day ago. Message volume also turned “extremely high” from “normal” the previous day.

Since the start of the year, OLMA shares have dropped by around 46%, but in the past 12 months, it has surged 205%.

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