User login
Plasmodium falciparum
Photo by Mae Melvin, CDC
In a phase 2 trial, a malaria vaccine candidate was able to prevent volunteers from contracting Plasmodium falciparum malaria.
The vaccine, known as PfSPZ vaccine, is composed of live but weakened P falciparum sporozoites.
Three to 5 doses of PfSPZ vaccine protected subjects against malaria parasites similar to those in the vaccine as well as parasites different from those in the vaccine.
A majority of subjects were protected at 3 weeks after vaccination. For some subjects, this protection was sustained at 24 weeks.
PfSPZ vaccine was considered well-tolerated, as all adverse events (AEs) in this trial were grade 1 or 2.
These results were published in JCI Insight.
The study was funded by the US Department of Defense through the Joint Warfighter Program, the Military Infectious Disease Research Program, and US Navy Advanced Medical Development, with additional support from Sanaria, Inc., the company developing PfSPZ vaccine.
“Our military continues to be at risk from malaria as it deploys worldwide,” said Kenneth A. Bertram, MD, of the US Army Medical Research and Materiel Command in Ft Detrick, Maryland.
“We are excited about the results of this clinical trial and are now investing in the ongoing clinical trial to finalize the vaccination regimen for PfSPZ vaccine.”
The current trial included 67 volunteers with a median age of 29.6 (range, 19 to 45).
They were randomized to 3 treatment groups. Forty-five subjects were set to receive the PfSPZ vaccine, and 22 subjects served as controls.
The volunteers underwent controlled human malaria infection (CHMI) 3 weeks after vaccinated subjects received their final vaccine dose and then again at 24 weeks.
Efficacy at 3 weeks
Group 1
In this group, 13 subjects received 5 doses of the vaccine at 2.7 × 105. They and 6 control subjects underwent CHMI with a homologous strain of P falciparum, Pf3D7.
Twelve of the 13 fully immunized subjects, or 92.3%, did not develop parasitemia. However, all 6 control subjects did, with a median prepatent period of 11.6 days. The prepatent period in the immunized subject who developed parasitemia was 13.9 days.
Group 2
In this group, 5 subjects received 5 doses of the vaccine at 2.7 × 105. They and 4 control subjects underwent CHMI with a heterologous strain of P falciparum, Pf7G8.
Four of the 5 fully immunized subjects, or 80%, did not develop parasitemia. However, all 4 control subjects did, with a median prepatent period of 11.9 days. The prepatent period in the fully immunized subject who developed parasitemia was 11.9 days.
Group 3
In this group, 15 subjects received 3 doses of the vaccine at 4.5 × 105 and underwent homologous Pf3D7 CHMI. The control subjects for this group were the same as those in group 1.
Thirteen of the 15 immunized subjects, or 86.7%, did not develop parasitemia. The prepatent periods in the 2 immunized subjects who did develop parasitemia were 13.9 days and 16.9 days.
Efficacy at 24 weeks
Study subjects underwent a second CHMI at 24 weeks after immunized participants received their final dose of vaccine.
Group 1
Seven of the 10 fully immunized subjects who underwent a second CHMI did not develop parasitemia (70%). However, all 6 control subjects did, with a median prepatent period of 11.6 days. The median prepatent period in the 3 fully immunized subjects who developed parasitemia was 15.4 days.
Group 2
One of the 10 fully immunized subjects who underwent a second CHMI did not develop parasitemia (10%). However, all control subjects did, with a median prepatent period of 10.9 days. The median prepatent period in the 9 fully immunized subjects who developed parasitemia was 11.9 days.
Group 3
Eight of the 14 fully immunized subjects who underwent a second CHMI did not develop parasitemia (57.1%). The median prepatent period in the 6 fully immunized subjects who did develop parasitemia was 14.0 days.
Safety
There were 66 solicited AEs reported within 7 days of immunization that were considered possibly, probably, or definitely related to vaccination. Ninety-two percent of these AEs were grade 1, and 8% were grade 2. All unsolicited AEs reported within 7 days of immunization were grade 1.
The incidence of AEs was not higher in group 3 than in groups 1 or 2, and the incidence of AEs did not increase as subjects received additional doses of the vaccine.
The most common AEs (with an incidence of 10% or higher in at least 1 group) were injection site pain, headache, fatigue, malaise, myalgia, injection site hemorrhage, and cough.
“The results of this clinical trial, along with recent results from other trials of this vaccine in the US and Africa, were critical to our decision to move forward with a trial involving 400 infants in Kenya,” said Tina Oneko, MD, of the Kenya Medical Research Institute, who is the principal investigator of the Kenya trial but was not involved in the current trial.
“This represents significant progress toward the development of a regimen for PfSPZ vaccine that we anticipate will provide a high level [of] efficacy for malaria prevention in all age groups in Africa.” 
Plasmodium falciparum
Photo by Mae Melvin, CDC
In a phase 2 trial, a malaria vaccine candidate was able to prevent volunteers from contracting Plasmodium falciparum malaria.
The vaccine, known as PfSPZ vaccine, is composed of live but weakened P falciparum sporozoites.
Three to 5 doses of PfSPZ vaccine protected subjects against malaria parasites similar to those in the vaccine as well as parasites different from those in the vaccine.
A majority of subjects were protected at 3 weeks after vaccination. For some subjects, this protection was sustained at 24 weeks.
PfSPZ vaccine was considered well-tolerated, as all adverse events (AEs) in this trial were grade 1 or 2.
These results were published in JCI Insight.
The study was funded by the US Department of Defense through the Joint Warfighter Program, the Military Infectious Disease Research Program, and US Navy Advanced Medical Development, with additional support from Sanaria, Inc., the company developing PfSPZ vaccine.
“Our military continues to be at risk from malaria as it deploys worldwide,” said Kenneth A. Bertram, MD, of the US Army Medical Research and Materiel Command in Ft Detrick, Maryland.
“We are excited about the results of this clinical trial and are now investing in the ongoing clinical trial to finalize the vaccination regimen for PfSPZ vaccine.”
The current trial included 67 volunteers with a median age of 29.6 (range, 19 to 45).
They were randomized to 3 treatment groups. Forty-five subjects were set to receive the PfSPZ vaccine, and 22 subjects served as controls.
The volunteers underwent controlled human malaria infection (CHMI) 3 weeks after vaccinated subjects received their final vaccine dose and then again at 24 weeks.
Efficacy at 3 weeks
Group 1
In this group, 13 subjects received 5 doses of the vaccine at 2.7 × 105. They and 6 control subjects underwent CHMI with a homologous strain of P falciparum, Pf3D7.
Twelve of the 13 fully immunized subjects, or 92.3%, did not develop parasitemia. However, all 6 control subjects did, with a median prepatent period of 11.6 days. The prepatent period in the immunized subject who developed parasitemia was 13.9 days.
Group 2
In this group, 5 subjects received 5 doses of the vaccine at 2.7 × 105. They and 4 control subjects underwent CHMI with a heterologous strain of P falciparum, Pf7G8.
Four of the 5 fully immunized subjects, or 80%, did not develop parasitemia. However, all 4 control subjects did, with a median prepatent period of 11.9 days. The prepatent period in the fully immunized subject who developed parasitemia was 11.9 days.
Group 3
In this group, 15 subjects received 3 doses of the vaccine at 4.5 × 105 and underwent homologous Pf3D7 CHMI. The control subjects for this group were the same as those in group 1.
Thirteen of the 15 immunized subjects, or 86.7%, did not develop parasitemia. The prepatent periods in the 2 immunized subjects who did develop parasitemia were 13.9 days and 16.9 days.
Efficacy at 24 weeks
Study subjects underwent a second CHMI at 24 weeks after immunized participants received their final dose of vaccine.
Group 1
Seven of the 10 fully immunized subjects who underwent a second CHMI did not develop parasitemia (70%). However, all 6 control subjects did, with a median prepatent period of 11.6 days. The median prepatent period in the 3 fully immunized subjects who developed parasitemia was 15.4 days.
Group 2
One of the 10 fully immunized subjects who underwent a second CHMI did not develop parasitemia (10%). However, all control subjects did, with a median prepatent period of 10.9 days. The median prepatent period in the 9 fully immunized subjects who developed parasitemia was 11.9 days.
Group 3
Eight of the 14 fully immunized subjects who underwent a second CHMI did not develop parasitemia (57.1%). The median prepatent period in the 6 fully immunized subjects who did develop parasitemia was 14.0 days.
Safety
There were 66 solicited AEs reported within 7 days of immunization that were considered possibly, probably, or definitely related to vaccination. Ninety-two percent of these AEs were grade 1, and 8% were grade 2. All unsolicited AEs reported within 7 days of immunization were grade 1.
The incidence of AEs was not higher in group 3 than in groups 1 or 2, and the incidence of AEs did not increase as subjects received additional doses of the vaccine.
The most common AEs (with an incidence of 10% or higher in at least 1 group) were injection site pain, headache, fatigue, malaise, myalgia, injection site hemorrhage, and cough.
“The results of this clinical trial, along with recent results from other trials of this vaccine in the US and Africa, were critical to our decision to move forward with a trial involving 400 infants in Kenya,” said Tina Oneko, MD, of the Kenya Medical Research Institute, who is the principal investigator of the Kenya trial but was not involved in the current trial.
“This represents significant progress toward the development of a regimen for PfSPZ vaccine that we anticipate will provide a high level [of] efficacy for malaria prevention in all age groups in Africa.”
Plasmodium falciparum
Photo by Mae Melvin, CDC
In a phase 2 trial, a malaria vaccine candidate was able to prevent volunteers from contracting Plasmodium falciparum malaria.
The vaccine, known as PfSPZ vaccine, is composed of live but weakened P falciparum sporozoites.
Three to 5 doses of PfSPZ vaccine protected subjects against malaria parasites similar to those in the vaccine as well as parasites different from those in the vaccine.
A majority of subjects were protected at 3 weeks after vaccination. For some subjects, this protection was sustained at 24 weeks.
PfSPZ vaccine was considered well-tolerated, as all adverse events (AEs) in this trial were grade 1 or 2.
These results were published in JCI Insight.
The study was funded by the US Department of Defense through the Joint Warfighter Program, the Military Infectious Disease Research Program, and US Navy Advanced Medical Development, with additional support from Sanaria, Inc., the company developing PfSPZ vaccine.
“Our military continues to be at risk from malaria as it deploys worldwide,” said Kenneth A. Bertram, MD, of the US Army Medical Research and Materiel Command in Ft Detrick, Maryland.
“We are excited about the results of this clinical trial and are now investing in the ongoing clinical trial to finalize the vaccination regimen for PfSPZ vaccine.”
The current trial included 67 volunteers with a median age of 29.6 (range, 19 to 45).
They were randomized to 3 treatment groups. Forty-five subjects were set to receive the PfSPZ vaccine, and 22 subjects served as controls.
The volunteers underwent controlled human malaria infection (CHMI) 3 weeks after vaccinated subjects received their final vaccine dose and then again at 24 weeks.
Efficacy at 3 weeks
Group 1
In this group, 13 subjects received 5 doses of the vaccine at 2.7 × 105. They and 6 control subjects underwent CHMI with a homologous strain of P falciparum, Pf3D7.
Twelve of the 13 fully immunized subjects, or 92.3%, did not develop parasitemia. However, all 6 control subjects did, with a median prepatent period of 11.6 days. The prepatent period in the immunized subject who developed parasitemia was 13.9 days.
Group 2
In this group, 5 subjects received 5 doses of the vaccine at 2.7 × 105. They and 4 control subjects underwent CHMI with a heterologous strain of P falciparum, Pf7G8.
Four of the 5 fully immunized subjects, or 80%, did not develop parasitemia. However, all 4 control subjects did, with a median prepatent period of 11.9 days. The prepatent period in the fully immunized subject who developed parasitemia was 11.9 days.
Group 3
In this group, 15 subjects received 3 doses of the vaccine at 4.5 × 105 and underwent homologous Pf3D7 CHMI. The control subjects for this group were the same as those in group 1.
Thirteen of the 15 immunized subjects, or 86.7%, did not develop parasitemia. The prepatent periods in the 2 immunized subjects who did develop parasitemia were 13.9 days and 16.9 days.
Efficacy at 24 weeks
Study subjects underwent a second CHMI at 24 weeks after immunized participants received their final dose of vaccine.
Group 1
Seven of the 10 fully immunized subjects who underwent a second CHMI did not develop parasitemia (70%). However, all 6 control subjects did, with a median prepatent period of 11.6 days. The median prepatent period in the 3 fully immunized subjects who developed parasitemia was 15.4 days.
Group 2
One of the 10 fully immunized subjects who underwent a second CHMI did not develop parasitemia (10%). However, all control subjects did, with a median prepatent period of 10.9 days. The median prepatent period in the 9 fully immunized subjects who developed parasitemia was 11.9 days.
Group 3
Eight of the 14 fully immunized subjects who underwent a second CHMI did not develop parasitemia (57.1%). The median prepatent period in the 6 fully immunized subjects who did develop parasitemia was 14.0 days.
Safety
There were 66 solicited AEs reported within 7 days of immunization that were considered possibly, probably, or definitely related to vaccination. Ninety-two percent of these AEs were grade 1, and 8% were grade 2. All unsolicited AEs reported within 7 days of immunization were grade 1.
The incidence of AEs was not higher in group 3 than in groups 1 or 2, and the incidence of AEs did not increase as subjects received additional doses of the vaccine.
The most common AEs (with an incidence of 10% or higher in at least 1 group) were injection site pain, headache, fatigue, malaise, myalgia, injection site hemorrhage, and cough.
“The results of this clinical trial, along with recent results from other trials of this vaccine in the US and Africa, were critical to our decision to move forward with a trial involving 400 infants in Kenya,” said Tina Oneko, MD, of the Kenya Medical Research Institute, who is the principal investigator of the Kenya trial but was not involved in the current trial.
“This represents significant progress toward the development of a regimen for PfSPZ vaccine that we anticipate will provide a high level [of] efficacy for malaria prevention in all age groups in Africa.”