Results Presented at EHA Show Significant Clinical Benefit, as Measured by Overall Response Rate and Progression Free Survival, when Treated with Melflufen and Dexamethasone,

Heavily Pretreated, Relapsed and Relapsed Refractory Multiple Myeloma Patients Showed Significant Clinical Benefit, as Measured by Overall Response Rate and Progression Free Survival, when Treated with Melflufen and Dexamethasone.

Oncopeptides AB, a clinical stage company developing a peptidase targeted therapy – melflufen –
presented clinical results from an ongoing Phase I/II study in patients with relapsed and relapsed
refractory multiple myeloma in combination with dexamethasone. The results, presented at the
European Hematology Association meeting in Vienna, showed an overall response rate (partial
response or better) of 52% and clinical benefit rate (minimal response or better) of 67% in efficacy
evaluable patients. At the date of analysis, the median progression-free survival was 7.6 months in the
total population with 56% of the patients still without disease progression. 90% of the patients were
refractory patients, 67% of patients were refractory to last line of treatment and 48% of patients were
double refractory to both IMiDs and proteasome inhibitors. The response rates were similar across
the different patient refractory status groups (single, double and triple refractory patients).
Melflufen 40 mg was well tolerated and the few treatment related serious adverse events reported in
this late stage patient population, 3 out of 29 patients, suggest that the primary toxicities of
thrombocytopenia and neutropenia are clinically manageable.

The results are from a clinical trial being carried out across four centers in Europe (Sweden, Italy, the
Netherlands and Denmark) and two in the USA (Boston, MA and Chapel Hill, NC), the results support
Oncopeptides’ belief that melflufen has the potential to provide an alternative when conventional therapies
have failed in relapsed and relapsed-refractory multiple myeloma.

Melflufen is a peptidase-targeted therapy and a potent antiangiogenic compound. It triggers rapid, robust, and
irreversible DNA damage and exerts it cytotoxicity through alkylation of DNA.

CEO, Jakob Lindberg commented “The trial results on the activity and safety of melflufen in combination
with dexamethasone are most encouraging and I am looking forward to building upon these findings as we
continue with the melflufen clinical program. There is a real need for more effective therapies to treat
refractory multiple myeloma and I believe that melflufen has the potential to deliver better treatment of the
disease.”

The poster entitled ‘Encouraging Preliminary Data in Ongoing Phase I/II study of Safety and Efficacy of
Melflufen and Dexamethasone for Patients with Relapsed and Relapsed-Refractory Multiple Myeloma’ can be
downloaded here www.oncopeptides.se

Multiple myeloma is the second most common hematological cancer and worldwide more than 180,000 people
are living with the disease, with approximately 86,000 new cases diagnosed annually (ref: International Agency
for Research on Cancer).

About Oncopeptides AB

Oncopeptides is a clinical stage pharmaceutical company developing oncology therapies around peptidase targeting.
Melflufen, Oncopeptides’ lead compound in clinical development, is a peptidase targeted therapy and a potent
antiangiogenic compound. It triggers rapid, robust, and irreversible DNA damage and exerts it cytotoxicity through
alkylation of DNA.