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Sellas Life Sciences (SLS) Is Monday’s Shining Star; Here’s Why


On a day like today, when the entire stock market is under pressure, you must have done something right to see your stock jump more than 150%. And Sellas Life Sciences Group (NASDAQ:SLS) definitely did something right.

The clinical-stage biopharmaceutical company announced positive interim data from the prospective, randomized, single-blinded, controlled Phase 2b independent investigator-sponsored clinical trial (IST) of trastuzumab (Herceptin®) +/- nelipepimut-S (NeuVax™)  in HER2 1+/2+ breast cancer patients in the adjuvant setting to prevent recurrences.

A pre-specified interim analysis, conducted by an independent Data Safety Monitoring Board (DSMB) of the efficacy and safety data for the study in an overall population of 275 patients as well as the two primary study target patient populations (node-positive and TNBC) after a median follow-up of 19 months,  demonstrated a clinically meaningful difference in median disease-free survival (DFS) in favor of the active arm (NeuVax + Herceptin), a primary endpoint of the study, with hazard ratios of 0.67 and 0.61 in the intent to treat (ITT) and modified ITT (mITT) populations (i.e., those who received at least one dose of vaccine or control) as well as a 34.9% and 39.5% reduction in relative risk of recurrence in the active versus control arms in the ITT and mITT populations, respectively.

A clinically meaningful and also statistically significant difference was found between the two arms in the cohort of patients (n= 98) with triple-negative breast cancer (TNBC), with a hazard ratio of 0.26 and a p-value of 0.023 in favor of the NeuVax + Herceptin combination with a 70.4% reduction in relative risk of recurrence in the active arm versus control.  Similarly, a clinically meaningful and statistically significant difference was found between the two arms in favor of the combination in the cohort of patients not receiving hormonal therapy (n = 110), with a hazard ratio of 0.24 and a p-value of 0.009 with a 74.1% reduction in relative risk of recurrence in the active arm versus control. This pre-specified interim analysis also showed an adverse event profile with no notable differences between treatment arms.  The addition of NeuVax to Herceptin did not result in any additional cardiotoxicity compared to Herceptin alone.

“We are indeed excited about these compelling results and believe NeuVax + Herceptin has the potential to become an important therapeutic option for TNBC patients.  The positive NeuVax phase 2b data underscores the innovative science and approach we have taken to investigate this agent’s potential to address this persistent therapeutic challenge.  We plan to immediately engage with the FDA and EMA, as per the recommendation of the DSMB, to identify the optimal path forward in this particular patient group, while advancing the drug through a partnership or other strategic collaboration,” said Angelos Stergiou, MD, ScD h.c., President and Chief Executive Officer of SELLAS. “These are indeed unique and exciting clinical data for TNBC patients, and I would like to extend my sincere gratitude to all patients who have participated in this clinical trial, as well as the study teams.”

The NeuVax + Herceptin combination was found to be generally well-tolerated. The majority of treatment-emergent adverse events (TEAE) were of mild or moderate (G1/G2) severity and the majority of G3 systemic TEAEs were unrelated to NeuVax.  Treatment-related adverse events consisted primarily of manageable local injection site reactions, skin induration, pruritus and fatigue.

Additionally, in the NeuVax + Herceptin arm, in vivo HER2-specific T-cell immune responses (IRs), assessed by delayed type hypersensitivity (DTH) skin testing, showed a time-dependent increase in IR potency compared to the earliest tested datapoint (p=0.000023), while no such increase was observed in the control arm.

Based on the results above, the DSMB has recommended to expeditiously seek regulatory guidance by the FDA for further development of the combination of NeuVax + Herceptin in TNBC, considering the statistically significant benefit of the combination therapy seen in this population with large unmet medical need.

“We are very pleased with these findings, which suggest that NeuVax + Herceptin may provide a clinically meaningful benefit to breast cancer patients with low-to-intermediate HER2-expression, especially given the recent report of the NSABP B-47 trial showing no benefit in these patients with Herceptin alone.  Furthermore, our trial has shown a significantly improved disease-free survival in women with TNBC.  The favorable findings for this cohort are particularly promising, given the limited treatment options for these patients with high risk of recurrence and death,” commented COL (ret) George E. Peoples, MD, FACS, the study director and sponsor-investigator of the IST. “We look forward to presenting these data at an upcoming major medical conference and to supporting SELLAS in the regulatory and developmental pathway for NeuVax.”

Analyst Ratings

Wall Street anchors a bullish perspective on the soaring biotech firm, as TipRanks analytics showcase SLS as a Buy. Based on 3 analysts polled in the last 12 months, all 3 rate Sellas Life stock a Buy. The 12-month average price target stands at $12, marking a nearly 36% upside from where the stock is currently trading.